Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2765 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
new file mode 100644
index 000000000..e40c93f09
--- /dev/null
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -0,0 +1,2765 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/anon_inodes.h>
+#include <linux/atomic.h>
+#include <linux/bitmap.h>
+#include <linux/build_bug.h>
+#include <linux/cdev.h>
+#include <linux/compat.h>
+#include <linux/compiler.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/file.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/poll.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <linux/hte.h>
+#include <uapi/linux/gpio.h>
+
+#include "gpiolib.h"
+#include "gpiolib-cdev.h"
+
+/*
+ * Array sizes must ensure 64-bit alignment and not create holes in the
+ * struct packing.
+ */
+static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
+static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
+
+/*
+ * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
+ */
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
+
+/* Character device interface to GPIO.
+ *
+ * The GPIO character device, /dev/gpiochipN, provides userspace an
+ * interface to gpiolib GPIOs via ioctl()s.
+ */
+
+typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
+typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
+typedef ssize_t (*read_fn)(struct file *, char __user *,
+			   size_t count, loff_t *);
+
+static __poll_t call_poll_locked(struct file *file,
+				 struct poll_table_struct *wait,
+				 struct gpio_device *gdev, poll_fn func)
+{
+	__poll_t ret;
+
+	down_read(&gdev->sem);
+	ret = func(file, wait);
+	up_read(&gdev->sem);
+
+	return ret;
+}
+
+static long call_ioctl_locked(struct file *file, unsigned int cmd,
+			      unsigned long arg, struct gpio_device *gdev,
+			      ioctl_fn func)
+{
+	long ret;
+
+	down_read(&gdev->sem);
+	ret = func(file, cmd, arg);
+	up_read(&gdev->sem);
+
+	return ret;
+}
+
+static ssize_t call_read_locked(struct file *file, char __user *buf,
+				size_t count, loff_t *f_ps,
+				struct gpio_device *gdev, read_fn func)
+{
+	ssize_t ret;
+
+	down_read(&gdev->sem);
+	ret = func(file, buf, count, f_ps);
+	up_read(&gdev->sem);
+
+	return ret;
+}
+
+/*
+ * GPIO line handle management
+ */
+
+#ifdef CONFIG_GPIO_CDEV_V1
+/**
+ * struct linehandle_state - contains the state of a userspace handle
+ * @gdev: the GPIO device the handle pertains to
+ * @label: consumer label used to tag descriptors
+ * @descs: the GPIO descriptors held by this handle
+ * @num_descs: the number of descriptors held in the descs array
+ */
+struct linehandle_state {
+	struct gpio_device *gdev;
+	const char *label;
+	struct gpio_desc *descs[GPIOHANDLES_MAX];
+	u32 num_descs;
+};
+
+#define GPIOHANDLE_REQUEST_VALID_FLAGS \
+	(GPIOHANDLE_REQUEST_INPUT | \
+	GPIOHANDLE_REQUEST_OUTPUT | \
+	GPIOHANDLE_REQUEST_ACTIVE_LOW | \
+	GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
+	GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
+	GPIOHANDLE_REQUEST_BIAS_DISABLE | \
+	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
+	GPIOHANDLE_REQUEST_OPEN_SOURCE)
+
+static int linehandle_validate_flags(u32 flags)
+{
+	/* Return an error if an unknown flag is set */
+	if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
+		return -EINVAL;
+
+	/*
+	 * Do not allow both INPUT & OUTPUT flags to be set as they are
+	 * contradictory.
+	 */
+	if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
+	    (flags & GPIOHANDLE_REQUEST_OUTPUT))
+		return -EINVAL;
+
+	/*
+	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
+	 * the hardware actually supports enabling both at the same time the
+	 * electrical result would be disastrous.
+	 */
+	if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
+	    (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
+	if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
+	    ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+	     (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
+		return -EINVAL;
+
+	/* Bias flags only allowed for input or output mode. */
+	if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
+	      (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
+	    ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
+		return -EINVAL;
+
+	/* Only one bias flag can be set. */
+	if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+	     (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+		       GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+	    ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
+{
+	assign_bit(FLAG_ACTIVE_LOW, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
+	assign_bit(FLAG_OPEN_DRAIN, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
+	assign_bit(FLAG_OPEN_SOURCE, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
+	assign_bit(FLAG_PULL_UP, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
+	assign_bit(FLAG_PULL_DOWN, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
+	assign_bit(FLAG_BIAS_DISABLE, flagsp,
+		   lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
+}
+
+static long linehandle_set_config(struct linehandle_state *lh,
+				  void __user *ip)
+{
+	struct gpiohandle_config gcnf;
+	struct gpio_desc *desc;
+	int i, ret;
+	u32 lflags;
+
+	if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
+		return -EFAULT;
+
+	lflags = gcnf.flags;
+	ret = linehandle_validate_flags(lflags);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < lh->num_descs; i++) {
+		desc = lh->descs[i];
+		linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
+
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+			int val = !!gcnf.default_values[i];
+
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				return ret;
+		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				return ret;
+		}
+
+		blocking_notifier_call_chain(&desc->gdev->notifier,
+					     GPIO_V2_LINE_CHANGED_CONFIG,
+					     desc);
+	}
+	return 0;
+}
+
+static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd,
+				      unsigned long arg)
+{
+	struct linehandle_state *lh = file->private_data;
+	void __user *ip = (void __user *)arg;
+	struct gpiohandle_data ghd;
+	DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
+	unsigned int i;
+	int ret;
+
+	if (!lh->gdev->chip)
+		return -ENODEV;
+
+	switch (cmd) {
+	case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
+		/* NOTE: It's okay to read values of output lines */
+		ret = gpiod_get_array_value_complex(false, true,
+						    lh->num_descs, lh->descs,
+						    NULL, vals);
+		if (ret)
+			return ret;
+
+		memset(&ghd, 0, sizeof(ghd));
+		for (i = 0; i < lh->num_descs; i++)
+			ghd.values[i] = test_bit(i, vals);
+
+		if (copy_to_user(ip, &ghd, sizeof(ghd)))
+			return -EFAULT;
+
+		return 0;
+	case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
+		/*
+		 * All line descriptors were created at once with the same
+		 * flags so just check if the first one is really output.
+		 */
+		if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
+			return -EPERM;
+
+		if (copy_from_user(&ghd, ip, sizeof(ghd)))
+			return -EFAULT;
+
+		/* Clamp all values to [0,1] */
+		for (i = 0; i < lh->num_descs; i++)
+			__assign_bit(i, vals, ghd.values[i]);
+
+		/* Reuse the array setting function */
+		return gpiod_set_array_value_complex(false,
+						     true,
+						     lh->num_descs,
+						     lh->descs,
+						     NULL,
+						     vals);
+	case GPIOHANDLE_SET_CONFIG_IOCTL:
+		return linehandle_set_config(lh, ip);
+	default:
+		return -EINVAL;
+	}
+}
+
+static long linehandle_ioctl(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct linehandle_state *lh = file->private_data;
+
+	return call_ioctl_locked(file, cmd, arg, lh->gdev,
+				 linehandle_ioctl_unlocked);
+}
+
+#ifdef CONFIG_COMPAT
+static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
+				    unsigned long arg)
+{
+	return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static void linehandle_free(struct linehandle_state *lh)
+{
+	int i;
+
+	for (i = 0; i < lh->num_descs; i++)
+		if (lh->descs[i])
+			gpiod_free(lh->descs[i]);
+	kfree(lh->label);
+	put_device(&lh->gdev->dev);
+	kfree(lh);
+}
+
+static int linehandle_release(struct inode *inode, struct file *file)
+{
+	linehandle_free(file->private_data);
+	return 0;
+}
+
+static const struct file_operations linehandle_fileops = {
+	.release = linehandle_release,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = linehandle_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = linehandle_ioctl_compat,
+#endif
+};
+
+static int linehandle_create(struct gpio_device *gdev, void __user *ip)
+{
+	struct gpiohandle_request handlereq;
+	struct linehandle_state *lh;
+	struct file *file;
+	int fd, i, ret;
+	u32 lflags;
+
+	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
+		return -EFAULT;
+	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
+		return -EINVAL;
+
+	lflags = handlereq.flags;
+
+	ret = linehandle_validate_flags(lflags);
+	if (ret)
+		return ret;
+
+	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
+	if (!lh)
+		return -ENOMEM;
+	lh->gdev = gdev;
+	get_device(&gdev->dev);
+
+	if (handlereq.consumer_label[0] != '\0') {
+		/* label is only initialized if consumer_label is set */
+		lh->label = kstrndup(handlereq.consumer_label,
+				     sizeof(handlereq.consumer_label) - 1,
+				     GFP_KERNEL);
+		if (!lh->label) {
+			ret = -ENOMEM;
+			goto out_free_lh;
+		}
+	}
+
+	lh->num_descs = handlereq.lines;
+
+	/* Request each GPIO */
+	for (i = 0; i < handlereq.lines; i++) {
+		u32 offset = handlereq.lineoffsets[i];
+		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+
+		if (IS_ERR(desc)) {
+			ret = PTR_ERR(desc);
+			goto out_free_lh;
+		}
+
+		ret = gpiod_request_user(desc, lh->label);
+		if (ret)
+			goto out_free_lh;
+		lh->descs[i] = desc;
+		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
+
+		ret = gpiod_set_transitory(desc, false);
+		if (ret < 0)
+			goto out_free_lh;
+
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+			int val = !!handlereq.default_values[i];
+
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				goto out_free_lh;
+		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				goto out_free_lh;
+		}
+
+		blocking_notifier_call_chain(&desc->gdev->notifier,
+					     GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
+			offset);
+	}
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto out_free_lh;
+	}
+
+	file = anon_inode_getfile("gpio-linehandle",
+				  &linehandle_fileops,
+				  lh,
+				  O_RDONLY | O_CLOEXEC);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_put_unused_fd;
+	}
+
+	handlereq.fd = fd;
+	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
+		/*
+		 * fput() will trigger the release() callback, so do not go onto
+		 * the regular error cleanup path here.
+		 */
+		fput(file);
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	fd_install(fd, file);
+
+	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
+		lh->num_descs);
+
+	return 0;
+
+out_put_unused_fd:
+	put_unused_fd(fd);
+out_free_lh:
+	linehandle_free(lh);
+	return ret;
+}
+#endif /* CONFIG_GPIO_CDEV_V1 */
+
+/**
+ * struct line - contains the state of a requested line
+ * @desc: the GPIO descriptor for this line.
+ * @req: the corresponding line request
+ * @irq: the interrupt triggered in response to events on this GPIO
+ * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
+ * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
+ * @timestamp_ns: cache for the timestamp storing it between hardirq and
+ * IRQ thread, used to bring the timestamp close to the actual event
+ * @req_seqno: the seqno for the current edge event in the sequence of
+ * events for the corresponding line request. This is drawn from the @req.
+ * @line_seqno: the seqno for the current edge event in the sequence of
+ * events for this line.
+ * @work: the worker that implements software debouncing
+ * @sw_debounced: flag indicating if the software debouncer is active
+ * @level: the current debounced physical level of the line
+ * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
+ * @raw_level: the line level at the time of event
+ * @total_discard_seq: the running counter of the discarded events
+ * @last_seqno: the last sequence number before debounce period expires
+ */
+struct line {
+	struct gpio_desc *desc;
+	/*
+	 * -- edge detector specific fields --
+	 */
+	struct linereq *req;
+	unsigned int irq;
+	/*
+	 * The flags for the active edge detector configuration.
+	 *
+	 * edflags is set by linereq_create(), linereq_free(), and
+	 * linereq_set_config_unlocked(), which are themselves mutually
+	 * exclusive, and is accessed by edge_irq_thread(),
+	 * process_hw_ts_thread() and debounce_work_func(),
+	 * which can all live with a slightly stale value.
+	 */
+	u64 edflags;
+	/*
+	 * timestamp_ns and req_seqno are accessed only by
+	 * edge_irq_handler() and edge_irq_thread(), which are themselves
+	 * mutually exclusive, so no additional protection is necessary.
+	 */
+	u64 timestamp_ns;
+	u32 req_seqno;
+	/*
+	 * line_seqno is accessed by either edge_irq_thread() or
+	 * debounce_work_func(), which are themselves mutually exclusive,
+	 * so no additional protection is necessary.
+	 */
+	u32 line_seqno;
+	/*
+	 * -- debouncer specific fields --
+	 */
+	struct delayed_work work;
+	/*
+	 * sw_debounce is accessed by linereq_set_config(), which is the
+	 * only setter, and linereq_get_values(), which can live with a
+	 * slightly stale value.
+	 */
+	unsigned int sw_debounced;
+	/*
+	 * level is accessed by debounce_work_func(), which is the only
+	 * setter, and linereq_get_values() which can live with a slightly
+	 * stale value.
+	 */
+	unsigned int level;
+#ifdef CONFIG_HTE
+	struct hte_ts_desc hdesc;
+	/*
+	 * HTE provider sets line level at the time of event. The valid
+	 * value is 0 or 1 and negative value for an error.
+	 */
+	int raw_level;
+	/*
+	 * when sw_debounce is set on HTE enabled line, this is running
+	 * counter of the discarded events.
+	 */
+	u32 total_discard_seq;
+	/*
+	 * when sw_debounce is set on HTE enabled line, this variable records
+	 * last sequence number before debounce period expires.
+	 */
+	u32 last_seqno;
+#endif /* CONFIG_HTE */
+};
+
+/**
+ * struct linereq - contains the state of a userspace line request
+ * @gdev: the GPIO device the line request pertains to
+ * @label: consumer label used to tag GPIO descriptors
+ * @num_lines: the number of lines in the lines array
+ * @wait: wait queue that handles blocking reads of events
+ * @event_buffer_size: the number of elements allocated in @events
+ * @events: KFIFO for the GPIO events
+ * @seqno: the sequence number for edge events generated on all lines in
+ * this line request.  Note that this is not used when @num_lines is 1, as
+ * the line_seqno is then the same and is cheaper to calculate.
+ * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
+ * of configuration, particularly multi-step accesses to desc flags.
+ * @lines: the lines held by this line request, with @num_lines elements.
+ */
+struct linereq {
+	struct gpio_device *gdev;
+	const char *label;
+	u32 num_lines;
+	wait_queue_head_t wait;
+	u32 event_buffer_size;
+	DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
+	atomic_t seqno;
+	struct mutex config_mutex;
+	struct line lines[];
+};
+
+#define GPIO_V2_LINE_BIAS_FLAGS \
+	(GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
+	 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
+	 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
+
+#define GPIO_V2_LINE_DIRECTION_FLAGS \
+	(GPIO_V2_LINE_FLAG_INPUT | \
+	 GPIO_V2_LINE_FLAG_OUTPUT)
+
+#define GPIO_V2_LINE_DRIVE_FLAGS \
+	(GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
+	 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
+
+#define GPIO_V2_LINE_EDGE_FLAGS \
+	(GPIO_V2_LINE_FLAG_EDGE_RISING | \
+	 GPIO_V2_LINE_FLAG_EDGE_FALLING)
+
+#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
+
+#define GPIO_V2_LINE_VALID_FLAGS \
+	(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
+	 GPIO_V2_LINE_DIRECTION_FLAGS | \
+	 GPIO_V2_LINE_DRIVE_FLAGS | \
+	 GPIO_V2_LINE_EDGE_FLAGS | \
+	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
+	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
+	 GPIO_V2_LINE_BIAS_FLAGS)
+
+/* subset of flags relevant for edge detector configuration */
+#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
+	(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
+	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
+	 GPIO_V2_LINE_EDGE_FLAGS)
+
+static void linereq_put_event(struct linereq *lr,
+			      struct gpio_v2_line_event *le)
+{
+	bool overflow = false;
+
+	spin_lock(&lr->wait.lock);
+	if (kfifo_is_full(&lr->events)) {
+		overflow = true;
+		kfifo_skip(&lr->events);
+	}
+	kfifo_in(&lr->events, le, 1);
+	spin_unlock(&lr->wait.lock);
+	if (!overflow)
+		wake_up_poll(&lr->wait, EPOLLIN);
+	else
+		pr_debug_ratelimited("event FIFO is full - event dropped\n");
+}
+
+static u64 line_event_timestamp(struct line *line)
+{
+	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
+		return ktime_get_real_ns();
+	else if (IS_ENABLED(CONFIG_HTE) &&
+		 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
+		return line->timestamp_ns;
+
+	return ktime_get_ns();
+}
+
+static u32 line_event_id(int level)
+{
+	return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
+		       GPIO_V2_LINE_EVENT_FALLING_EDGE;
+}
+
+#ifdef CONFIG_HTE
+
+static enum hte_return process_hw_ts_thread(void *p)
+{
+	struct line *line;
+	struct linereq *lr;
+	struct gpio_v2_line_event le;
+	u64 edflags;
+	int level;
+
+	if (!p)
+		return HTE_CB_HANDLED;
+
+	line = p;
+	lr = line->req;
+
+	memset(&le, 0, sizeof(le));
+
+	le.timestamp_ns = line->timestamp_ns;
+	edflags = READ_ONCE(line->edflags);
+
+	switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
+	case GPIO_V2_LINE_FLAG_EDGE_BOTH:
+		level = (line->raw_level >= 0) ?
+				line->raw_level :
+				gpiod_get_raw_value_cansleep(line->desc);
+
+		if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
+			level = !level;
+
+		le.id = line_event_id(level);
+		break;
+	case GPIO_V2_LINE_FLAG_EDGE_RISING:
+		le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
+		break;
+	case GPIO_V2_LINE_FLAG_EDGE_FALLING:
+		le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
+		break;
+	default:
+		return HTE_CB_HANDLED;
+	}
+	le.line_seqno = line->line_seqno;
+	le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
+	le.offset = gpio_chip_hwgpio(line->desc);
+
+	linereq_put_event(lr, &le);
+
+	return HTE_CB_HANDLED;
+}
+
+static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
+{
+	struct line *line;
+	struct linereq *lr;
+	int diff_seqno = 0;
+
+	if (!ts || !p)
+		return HTE_CB_HANDLED;
+
+	line = p;
+	line->timestamp_ns = ts->tsc;
+	line->raw_level = ts->raw_level;
+	lr = line->req;
+
+	if (READ_ONCE(line->sw_debounced)) {
+		line->total_discard_seq++;
+		line->last_seqno = ts->seq;
+		mod_delayed_work(system_wq, &line->work,
+		  usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
+	} else {
+		if (unlikely(ts->seq < line->line_seqno))
+			return HTE_CB_HANDLED;
+
+		diff_seqno = ts->seq - line->line_seqno;
+		line->line_seqno = ts->seq;
+		if (lr->num_lines != 1)
+			line->req_seqno = atomic_add_return(diff_seqno,
+							    &lr->seqno);
+
+		return HTE_RUN_SECOND_CB;
+	}
+
+	return HTE_CB_HANDLED;
+}
+
+static int hte_edge_setup(struct line *line, u64 eflags)
+{
+	int ret;
+	unsigned long flags = 0;
+	struct hte_ts_desc *hdesc = &line->hdesc;
+
+	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
+		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+				 HTE_FALLING_EDGE_TS :
+				 HTE_RISING_EDGE_TS;
+	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
+		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+				 HTE_RISING_EDGE_TS :
+				 HTE_FALLING_EDGE_TS;
+
+	line->total_discard_seq = 0;
+
+	hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
+			   line->desc);
+
+	ret = hte_ts_get(NULL, hdesc, 0);
+	if (ret)
+		return ret;
+
+	return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
+				 line);
+}
+
+#else
+
+static int hte_edge_setup(struct line *line, u64 eflags)
+{
+	return 0;
+}
+#endif /* CONFIG_HTE */
+
+static irqreturn_t edge_irq_thread(int irq, void *p)
+{
+	struct line *line = p;
+	struct linereq *lr = line->req;
+	struct gpio_v2_line_event le;
+
+	/* Do not leak kernel stack to userspace */
+	memset(&le, 0, sizeof(le));
+
+	if (line->timestamp_ns) {
+		le.timestamp_ns = line->timestamp_ns;
+	} else {
+		/*
+		 * We may be running from a nested threaded interrupt in
+		 * which case we didn't get the timestamp from
+		 * edge_irq_handler().
+		 */
+		le.timestamp_ns = line_event_timestamp(line);
+		if (lr->num_lines != 1)
+			line->req_seqno = atomic_inc_return(&lr->seqno);
+	}
+	line->timestamp_ns = 0;
+
+	switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
+	case GPIO_V2_LINE_FLAG_EDGE_BOTH:
+		le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
+		break;
+	case GPIO_V2_LINE_FLAG_EDGE_RISING:
+		le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
+		break;
+	case GPIO_V2_LINE_FLAG_EDGE_FALLING:
+		le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
+		break;
+	default:
+		return IRQ_NONE;
+	}
+	line->line_seqno++;
+	le.line_seqno = line->line_seqno;
+	le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
+	le.offset = gpio_chip_hwgpio(line->desc);
+
+	linereq_put_event(lr, &le);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t edge_irq_handler(int irq, void *p)
+{
+	struct line *line = p;
+	struct linereq *lr = line->req;
+
+	/*
+	 * Just store the timestamp in hardirq context so we get it as
+	 * close in time as possible to the actual event.
+	 */
+	line->timestamp_ns = line_event_timestamp(line);
+
+	if (lr->num_lines != 1)
+		line->req_seqno = atomic_inc_return(&lr->seqno);
+
+	return IRQ_WAKE_THREAD;
+}
+
+/*
+ * returns the current debounced logical value.
+ */
+static bool debounced_value(struct line *line)
+{
+	bool value;
+
+	/*
+	 * minor race - debouncer may be stopped here, so edge_detector_stop()
+	 * must leave the value unchanged so the following will read the level
+	 * from when the debouncer was last running.
+	 */
+	value = READ_ONCE(line->level);
+
+	if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
+		value = !value;
+
+	return value;
+}
+
+static irqreturn_t debounce_irq_handler(int irq, void *p)
+{
+	struct line *line = p;
+
+	mod_delayed_work(system_wq, &line->work,
+		usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
+
+	return IRQ_HANDLED;
+}
+
+static void debounce_work_func(struct work_struct *work)
+{
+	struct gpio_v2_line_event le;
+	struct line *line = container_of(work, struct line, work.work);
+	struct linereq *lr;
+	u64 eflags, edflags = READ_ONCE(line->edflags);
+	int level = -1;
+#ifdef CONFIG_HTE
+	int diff_seqno;
+
+	if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
+		level = line->raw_level;
+#endif
+	if (level < 0)
+		level = gpiod_get_raw_value_cansleep(line->desc);
+	if (level < 0) {
+		pr_debug_ratelimited("debouncer failed to read line value\n");
+		return;
+	}
+
+	if (READ_ONCE(line->level) == level)
+		return;
+
+	WRITE_ONCE(line->level, level);
+
+	/* -- edge detection -- */
+	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
+	if (!eflags)
+		return;
+
+	/* switch from physical level to logical - if they differ */
+	if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
+		level = !level;
+
+	/* ignore edges that are not being monitored */
+	if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
+	    ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
+		return;
+
+	/* Do not leak kernel stack to userspace */
+	memset(&le, 0, sizeof(le));
+
+	lr = line->req;
+	le.timestamp_ns = line_event_timestamp(line);
+	le.offset = gpio_chip_hwgpio(line->desc);
+#ifdef CONFIG_HTE
+	if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
+		/* discard events except the last one */
+		line->total_discard_seq -= 1;
+		diff_seqno = line->last_seqno - line->total_discard_seq -
+				line->line_seqno;
+		line->line_seqno = line->last_seqno - line->total_discard_seq;
+		le.line_seqno = line->line_seqno;
+		le.seqno = (lr->num_lines == 1) ?
+			le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
+	} else
+#endif /* CONFIG_HTE */
+	{
+		line->line_seqno++;
+		le.line_seqno = line->line_seqno;
+		le.seqno = (lr->num_lines == 1) ?
+			le.line_seqno : atomic_inc_return(&lr->seqno);
+	}
+
+	le.id = line_event_id(level);
+
+	linereq_put_event(lr, &le);
+}
+
+static int debounce_setup(struct line *line, unsigned int debounce_period_us)
+{
+	unsigned long irqflags;
+	int ret, level, irq;
+
+	/* try hardware */
+	ret = gpiod_set_debounce(line->desc, debounce_period_us);
+	if (!ret) {
+		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+		return ret;
+	}
+	if (ret != -ENOTSUPP)
+		return ret;
+
+	if (debounce_period_us) {
+		/* setup software debounce */
+		level = gpiod_get_raw_value_cansleep(line->desc);
+		if (level < 0)
+			return level;
+
+		if (!(IS_ENABLED(CONFIG_HTE) &&
+		      test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
+			irq = gpiod_to_irq(line->desc);
+			if (irq < 0)
+				return -ENXIO;
+
+			irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
+			ret = request_irq(irq, debounce_irq_handler, irqflags,
+					  line->req->label, line);
+			if (ret)
+				return ret;
+			line->irq = irq;
+		} else {
+			ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
+			if (ret)
+				return ret;
+		}
+
+		WRITE_ONCE(line->level, level);
+		WRITE_ONCE(line->sw_debounced, 1);
+	}
+	return 0;
+}
+
+static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
+					  unsigned int line_idx)
+{
+	unsigned int i;
+	u64 mask = BIT_ULL(line_idx);
+
+	for (i = 0; i < lc->num_attrs; i++) {
+		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
+		    (lc->attrs[i].mask & mask))
+			return true;
+	}
+	return false;
+}
+
+static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
+					       unsigned int line_idx)
+{
+	unsigned int i;
+	u64 mask = BIT_ULL(line_idx);
+
+	for (i = 0; i < lc->num_attrs; i++) {
+		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
+		    (lc->attrs[i].mask & mask))
+			return lc->attrs[i].attr.debounce_period_us;
+	}
+	return 0;
+}
+
+static void edge_detector_stop(struct line *line)
+{
+	if (line->irq) {
+		free_irq(line->irq, line);
+		line->irq = 0;
+	}
+
+#ifdef CONFIG_HTE
+	if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
+		hte_ts_put(&line->hdesc);
+#endif
+
+	cancel_delayed_work_sync(&line->work);
+	WRITE_ONCE(line->sw_debounced, 0);
+	WRITE_ONCE(line->edflags, 0);
+	if (line->desc)
+		WRITE_ONCE(line->desc->debounce_period_us, 0);
+	/* do not change line->level - see comment in debounced_value() */
+}
+
+static int edge_detector_setup(struct line *line,
+			       struct gpio_v2_line_config *lc,
+			       unsigned int line_idx, u64 edflags)
+{
+	u32 debounce_period_us;
+	unsigned long irqflags = 0;
+	u64 eflags;
+	int irq, ret;
+
+	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
+	if (eflags && !kfifo_initialized(&line->req->events)) {
+		ret = kfifo_alloc(&line->req->events,
+				  line->req->event_buffer_size, GFP_KERNEL);
+		if (ret)
+			return ret;
+	}
+	if (gpio_v2_line_config_debounced(lc, line_idx)) {
+		debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
+		ret = debounce_setup(line, debounce_period_us);
+		if (ret)
+			return ret;
+		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+	}
+
+	/* detection disabled or sw debouncer will provide edge detection */
+	if (!eflags || READ_ONCE(line->sw_debounced))
+		return 0;
+
+	if (IS_ENABLED(CONFIG_HTE) &&
+	    (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
+		return hte_edge_setup(line, edflags);
+
+	irq = gpiod_to_irq(line->desc);
+	if (irq < 0)
+		return -ENXIO;
+
+	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+	irqflags |= IRQF_ONESHOT;
+
+	/* Request a thread to read the events */
+	ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
+				   irqflags, line->req->label, line);
+	if (ret)
+		return ret;
+
+	line->irq = irq;
+	return 0;
+}
+
+static int edge_detector_update(struct line *line,
+				struct gpio_v2_line_config *lc,
+				unsigned int line_idx, u64 edflags)
+{
+	u64 active_edflags = READ_ONCE(line->edflags);
+	unsigned int debounce_period_us =
+			gpio_v2_line_config_debounce_period(lc, line_idx);
+
+	if ((active_edflags == edflags) &&
+	    (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
+		return 0;
+
+	/* sw debounced and still will be...*/
+	if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
+		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+		return 0;
+	}
+
+	/* reconfiguring edge detection or sw debounce being disabled */
+	if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
+	    (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
+	    (!debounce_period_us && READ_ONCE(line->sw_debounced)))
+		edge_detector_stop(line);
+
+	return edge_detector_setup(line, lc, line_idx, edflags);
+}
+
+static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
+				     unsigned int line_idx)
+{
+	unsigned int i;
+	u64 mask = BIT_ULL(line_idx);
+
+	for (i = 0; i < lc->num_attrs; i++) {
+		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
+		    (lc->attrs[i].mask & mask))
+			return lc->attrs[i].attr.flags;
+	}
+	return lc->flags;
+}
+
+static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
+					    unsigned int line_idx)
+{
+	unsigned int i;
+	u64 mask = BIT_ULL(line_idx);
+
+	for (i = 0; i < lc->num_attrs; i++) {
+		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
+		    (lc->attrs[i].mask & mask))
+			return !!(lc->attrs[i].attr.values & mask);
+	}
+	return 0;
+}
+
+static int gpio_v2_line_flags_validate(u64 flags)
+{
+	/* Return an error if an unknown flag is set */
+	if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
+		return -EINVAL;
+
+	if (!IS_ENABLED(CONFIG_HTE) &&
+	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
+		return -EOPNOTSUPP;
+
+	/*
+	 * Do not allow both INPUT and OUTPUT flags to be set as they are
+	 * contradictory.
+	 */
+	if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
+	    (flags & GPIO_V2_LINE_FLAG_OUTPUT))
+		return -EINVAL;
+
+	/* Only allow one event clock source */
+	if (IS_ENABLED(CONFIG_HTE) &&
+	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
+	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
+		return -EINVAL;
+
+	/* Edge detection requires explicit input. */
+	if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
+	    !(flags & GPIO_V2_LINE_FLAG_INPUT))
+		return -EINVAL;
+
+	/*
+	 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
+	 * request. If the hardware actually supports enabling both at the
+	 * same time the electrical result would be disastrous.
+	 */
+	if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
+	    (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* Drive requires explicit output direction. */
+	if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
+	    !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
+		return -EINVAL;
+
+	/* Bias requires explicit direction. */
+	if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
+	    !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
+		return -EINVAL;
+
+	/* Only one bias flag can be set. */
+	if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
+	     (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
+		       GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
+	    ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
+	     (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
+					unsigned int num_lines)
+{
+	unsigned int i;
+	u64 flags;
+	int ret;
+
+	if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
+		return -EINVAL;
+
+	if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
+		return -EINVAL;
+
+	for (i = 0; i < num_lines; i++) {
+		flags = gpio_v2_line_config_flags(lc, i);
+		ret = gpio_v2_line_flags_validate(flags);
+		if (ret)
+			return ret;
+
+		/* debounce requires explicit input */
+		if (gpio_v2_line_config_debounced(lc, i) &&
+		    !(flags & GPIO_V2_LINE_FLAG_INPUT))
+			return -EINVAL;
+	}
+	return 0;
+}
+
+static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
+						    unsigned long *flagsp)
+{
+	assign_bit(FLAG_ACTIVE_LOW, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
+
+	if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
+		set_bit(FLAG_IS_OUT, flagsp);
+	else if (flags & GPIO_V2_LINE_FLAG_INPUT)
+		clear_bit(FLAG_IS_OUT, flagsp);
+
+	assign_bit(FLAG_EDGE_RISING, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
+	assign_bit(FLAG_EDGE_FALLING, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
+
+	assign_bit(FLAG_OPEN_DRAIN, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
+	assign_bit(FLAG_OPEN_SOURCE, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
+
+	assign_bit(FLAG_PULL_UP, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
+	assign_bit(FLAG_PULL_DOWN, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
+	assign_bit(FLAG_BIAS_DISABLE, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
+
+	assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
+	assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
+		   flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
+}
+
+static long linereq_get_values(struct linereq *lr, void __user *ip)
+{
+	struct gpio_v2_line_values lv;
+	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+	struct gpio_desc **descs;
+	unsigned int i, didx, num_get;
+	bool val;
+	int ret;
+
+	/* NOTE: It's ok to read values of output lines. */
+	if (copy_from_user(&lv, ip, sizeof(lv)))
+		return -EFAULT;
+
+	for (num_get = 0, i = 0; i < lr->num_lines; i++) {
+		if (lv.mask & BIT_ULL(i)) {
+			num_get++;
+			descs = &lr->lines[i].desc;
+		}
+	}
+
+	if (num_get == 0)
+		return -EINVAL;
+
+	if (num_get != 1) {
+		descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
+		if (!descs)
+			return -ENOMEM;
+		for (didx = 0, i = 0; i < lr->num_lines; i++) {
+			if (lv.mask & BIT_ULL(i)) {
+				descs[didx] = lr->lines[i].desc;
+				didx++;
+			}
+		}
+	}
+	ret = gpiod_get_array_value_complex(false, true, num_get,
+					    descs, NULL, vals);
+
+	if (num_get != 1)
+		kfree(descs);
+	if (ret)
+		return ret;
+
+	lv.bits = 0;
+	for (didx = 0, i = 0; i < lr->num_lines; i++) {
+		if (lv.mask & BIT_ULL(i)) {
+			if (lr->lines[i].sw_debounced)
+				val = debounced_value(&lr->lines[i]);
+			else
+				val = test_bit(didx, vals);
+			if (val)
+				lv.bits |= BIT_ULL(i);
+			didx++;
+		}
+	}
+
+	if (copy_to_user(ip, &lv, sizeof(lv)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long linereq_set_values_unlocked(struct linereq *lr,
+					struct gpio_v2_line_values *lv)
+{
+	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+	struct gpio_desc **descs;
+	unsigned int i, didx, num_set;
+	int ret;
+
+	bitmap_zero(vals, GPIO_V2_LINES_MAX);
+	for (num_set = 0, i = 0; i < lr->num_lines; i++) {
+		if (lv->mask & BIT_ULL(i)) {
+			if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
+				return -EPERM;
+			if (lv->bits & BIT_ULL(i))
+				__set_bit(num_set, vals);
+			num_set++;
+			descs = &lr->lines[i].desc;
+		}
+	}
+	if (num_set == 0)
+		return -EINVAL;
+
+	if (num_set != 1) {
+		/* build compacted desc array and values */
+		descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
+		if (!descs)
+			return -ENOMEM;
+		for (didx = 0, i = 0; i < lr->num_lines; i++) {
+			if (lv->mask & BIT_ULL(i)) {
+				descs[didx] = lr->lines[i].desc;
+				didx++;
+			}
+		}
+	}
+	ret = gpiod_set_array_value_complex(false, true, num_set,
+					    descs, NULL, vals);
+
+	if (num_set != 1)
+		kfree(descs);
+	return ret;
+}
+
+static long linereq_set_values(struct linereq *lr, void __user *ip)
+{
+	struct gpio_v2_line_values lv;
+	int ret;
+
+	if (copy_from_user(&lv, ip, sizeof(lv)))
+		return -EFAULT;
+
+	mutex_lock(&lr->config_mutex);
+
+	ret = linereq_set_values_unlocked(lr, &lv);
+
+	mutex_unlock(&lr->config_mutex);
+
+	return ret;
+}
+
+static long linereq_set_config_unlocked(struct linereq *lr,
+					struct gpio_v2_line_config *lc)
+{
+	struct gpio_desc *desc;
+	struct line *line;
+	unsigned int i;
+	u64 flags, edflags;
+	int ret;
+
+	for (i = 0; i < lr->num_lines; i++) {
+		line = &lr->lines[i];
+		desc = lr->lines[i].desc;
+		flags = gpio_v2_line_config_flags(lc, i);
+		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+			int val = gpio_v2_line_config_output_value(lc, i);
+
+			edge_detector_stop(line);
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				return ret;
+		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				return ret;
+
+			ret = edge_detector_update(line, lc, i, edflags);
+			if (ret)
+				return ret;
+		}
+
+		WRITE_ONCE(line->edflags, edflags);
+
+		blocking_notifier_call_chain(&desc->gdev->notifier,
+					     GPIO_V2_LINE_CHANGED_CONFIG,
+					     desc);
+	}
+	return 0;
+}
+
+static long linereq_set_config(struct linereq *lr, void __user *ip)
+{
+	struct gpio_v2_line_config lc;
+	int ret;
+
+	if (copy_from_user(&lc, ip, sizeof(lc)))
+		return -EFAULT;
+
+	ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
+	if (ret)
+		return ret;
+
+	mutex_lock(&lr->config_mutex);
+
+	ret = linereq_set_config_unlocked(lr, &lc);
+
+	mutex_unlock(&lr->config_mutex);
+
+	return ret;
+}
+
+static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	struct linereq *lr = file->private_data;
+	void __user *ip = (void __user *)arg;
+
+	if (!lr->gdev->chip)
+		return -ENODEV;
+
+	switch (cmd) {
+	case GPIO_V2_LINE_GET_VALUES_IOCTL:
+		return linereq_get_values(lr, ip);
+	case GPIO_V2_LINE_SET_VALUES_IOCTL:
+		return linereq_set_values(lr, ip);
+	case GPIO_V2_LINE_SET_CONFIG_IOCTL:
+		return linereq_set_config(lr, ip);
+	default:
+		return -EINVAL;
+	}
+}
+
+static long linereq_ioctl(struct file *file, unsigned int cmd,
+			  unsigned long arg)
+{
+	struct linereq *lr = file->private_data;
+
+	return call_ioctl_locked(file, cmd, arg, lr->gdev,
+				 linereq_ioctl_unlocked);
+}
+
+#ifdef CONFIG_COMPAT
+static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static __poll_t linereq_poll_unlocked(struct file *file,
+				      struct poll_table_struct *wait)
+{
+	struct linereq *lr = file->private_data;
+	__poll_t events = 0;
+
+	if (!lr->gdev->chip)
+		return EPOLLHUP | EPOLLERR;
+
+	poll_wait(file, &lr->wait, wait);
+
+	if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
+						 &lr->wait.lock))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static __poll_t linereq_poll(struct file *file,
+			     struct poll_table_struct *wait)
+{
+	struct linereq *lr = file->private_data;
+
+	return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked);
+}
+
+static ssize_t linereq_read_unlocked(struct file *file, char __user *buf,
+				     size_t count, loff_t *f_ps)
+{
+	struct linereq *lr = file->private_data;
+	struct gpio_v2_line_event le;
+	ssize_t bytes_read = 0;
+	int ret;
+
+	if (!lr->gdev->chip)
+		return -ENODEV;
+
+	if (count < sizeof(le))
+		return -EINVAL;
+
+	do {
+		spin_lock(&lr->wait.lock);
+		if (kfifo_is_empty(&lr->events)) {
+			if (bytes_read) {
+				spin_unlock(&lr->wait.lock);
+				return bytes_read;
+			}
+
+			if (file->f_flags & O_NONBLOCK) {
+				spin_unlock(&lr->wait.lock);
+				return -EAGAIN;
+			}
+
+			ret = wait_event_interruptible_locked(lr->wait,
+					!kfifo_is_empty(&lr->events));
+			if (ret) {
+				spin_unlock(&lr->wait.lock);
+				return ret;
+			}
+		}
+
+		ret = kfifo_out(&lr->events, &le, 1);
+		spin_unlock(&lr->wait.lock);
+		if (ret != 1) {
+			/*
+			 * This should never happen - we were holding the
+			 * lock from the moment we learned the fifo is no
+			 * longer empty until now.
+			 */
+			ret = -EIO;
+			break;
+		}
+
+		if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
+			return -EFAULT;
+		bytes_read += sizeof(le);
+	} while (count >= bytes_read + sizeof(le));
+
+	return bytes_read;
+}
+
+static ssize_t linereq_read(struct file *file, char __user *buf,
+			    size_t count, loff_t *f_ps)
+{
+	struct linereq *lr = file->private_data;
+
+	return call_read_locked(file, buf, count, f_ps, lr->gdev,
+				linereq_read_unlocked);
+}
+
+static void linereq_free(struct linereq *lr)
+{
+	unsigned int i;
+
+	for (i = 0; i < lr->num_lines; i++) {
+		if (lr->lines[i].desc) {
+			edge_detector_stop(&lr->lines[i]);
+			gpiod_free(lr->lines[i].desc);
+		}
+	}
+	kfifo_free(&lr->events);
+	kfree(lr->label);
+	put_device(&lr->gdev->dev);
+	kfree(lr);
+}
+
+static int linereq_release(struct inode *inode, struct file *file)
+{
+	struct linereq *lr = file->private_data;
+
+	linereq_free(lr);
+	return 0;
+}
+
+#ifdef CONFIG_PROC_FS
+static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
+{
+	struct linereq *lr = file->private_data;
+	struct device *dev = &lr->gdev->dev;
+	u16 i;
+
+	seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
+
+	for (i = 0; i < lr->num_lines; i++)
+		seq_printf(out, "gpio-line:\t%d\n",
+			   gpio_chip_hwgpio(lr->lines[i].desc));
+}
+#endif
+
+static const struct file_operations line_fileops = {
+	.release = linereq_release,
+	.read = linereq_read,
+	.poll = linereq_poll,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = linereq_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = linereq_ioctl_compat,
+#endif
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo = linereq_show_fdinfo,
+#endif
+};
+
+static int linereq_create(struct gpio_device *gdev, void __user *ip)
+{
+	struct gpio_v2_line_request ulr;
+	struct gpio_v2_line_config *lc;
+	struct linereq *lr;
+	struct file *file;
+	u64 flags, edflags;
+	unsigned int i;
+	int fd, ret;
+
+	if (copy_from_user(&ulr, ip, sizeof(ulr)))
+		return -EFAULT;
+
+	if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
+		return -EINVAL;
+
+	if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
+		return -EINVAL;
+
+	lc = &ulr.config;
+	ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
+	if (ret)
+		return ret;
+
+	lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
+	if (!lr)
+		return -ENOMEM;
+
+	lr->gdev = gdev;
+	get_device(&gdev->dev);
+
+	for (i = 0; i < ulr.num_lines; i++) {
+		lr->lines[i].req = lr;
+		WRITE_ONCE(lr->lines[i].sw_debounced, 0);
+		INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
+	}
+
+	if (ulr.consumer[0] != '\0') {
+		/* label is only initialized if consumer is set */
+		lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
+				     GFP_KERNEL);
+		if (!lr->label) {
+			ret = -ENOMEM;
+			goto out_free_linereq;
+		}
+	}
+
+	mutex_init(&lr->config_mutex);
+	init_waitqueue_head(&lr->wait);
+	lr->event_buffer_size = ulr.event_buffer_size;
+	if (lr->event_buffer_size == 0)
+		lr->event_buffer_size = ulr.num_lines * 16;
+	else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
+		lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
+
+	atomic_set(&lr->seqno, 0);
+	lr->num_lines = ulr.num_lines;
+
+	/* Request each GPIO */
+	for (i = 0; i < ulr.num_lines; i++) {
+		u32 offset = ulr.offsets[i];
+		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+
+		if (IS_ERR(desc)) {
+			ret = PTR_ERR(desc);
+			goto out_free_linereq;
+		}
+
+		ret = gpiod_request_user(desc, lr->label);
+		if (ret)
+			goto out_free_linereq;
+
+		lr->lines[i].desc = desc;
+		flags = gpio_v2_line_config_flags(lc, i);
+		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+
+		ret = gpiod_set_transitory(desc, false);
+		if (ret < 0)
+			goto out_free_linereq;
+
+		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+			int val = gpio_v2_line_config_output_value(lc, i);
+
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				goto out_free_linereq;
+		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				goto out_free_linereq;
+
+			ret = edge_detector_setup(&lr->lines[i], lc, i,
+						  edflags);
+			if (ret)
+				goto out_free_linereq;
+		}
+
+		lr->lines[i].edflags = edflags;
+
+		blocking_notifier_call_chain(&desc->gdev->notifier,
+					     GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
+			offset);
+	}
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto out_free_linereq;
+	}
+
+	file = anon_inode_getfile("gpio-line", &line_fileops, lr,
+				  O_RDONLY | O_CLOEXEC);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_put_unused_fd;
+	}
+
+	ulr.fd = fd;
+	if (copy_to_user(ip, &ulr, sizeof(ulr))) {
+		/*
+		 * fput() will trigger the release() callback, so do not go onto
+		 * the regular error cleanup path here.
+		 */
+		fput(file);
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	fd_install(fd, file);
+
+	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
+		lr->num_lines);
+
+	return 0;
+
+out_put_unused_fd:
+	put_unused_fd(fd);
+out_free_linereq:
+	linereq_free(lr);
+	return ret;
+}
+
+#ifdef CONFIG_GPIO_CDEV_V1
+
+/*
+ * GPIO line event management
+ */
+
+/**
+ * struct lineevent_state - contains the state of a userspace event
+ * @gdev: the GPIO device the event pertains to
+ * @label: consumer label used to tag descriptors
+ * @desc: the GPIO descriptor held by this event
+ * @eflags: the event flags this line was requested with
+ * @irq: the interrupt that trigger in response to events on this GPIO
+ * @wait: wait queue that handles blocking reads of events
+ * @events: KFIFO for the GPIO events
+ * @timestamp: cache for the timestamp storing it between hardirq
+ * and IRQ thread, used to bring the timestamp close to the actual
+ * event
+ */
+struct lineevent_state {
+	struct gpio_device *gdev;
+	const char *label;
+	struct gpio_desc *desc;
+	u32 eflags;
+	int irq;
+	wait_queue_head_t wait;
+	DECLARE_KFIFO(events, struct gpioevent_data, 16);
+	u64 timestamp;
+};
+
+#define GPIOEVENT_REQUEST_VALID_FLAGS \
+	(GPIOEVENT_REQUEST_RISING_EDGE | \
+	GPIOEVENT_REQUEST_FALLING_EDGE)
+
+static __poll_t lineevent_poll_unlocked(struct file *file,
+					struct poll_table_struct *wait)
+{
+	struct lineevent_state *le = file->private_data;
+	__poll_t events = 0;
+
+	if (!le->gdev->chip)
+		return EPOLLHUP | EPOLLERR;
+
+	poll_wait(file, &le->wait, wait);
+
+	if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static __poll_t lineevent_poll(struct file *file,
+			       struct poll_table_struct *wait)
+{
+	struct lineevent_state *le = file->private_data;
+
+	return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked);
+}
+
+struct compat_gpioeevent_data {
+	compat_u64	timestamp;
+	u32		id;
+};
+
+static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf,
+				       size_t count, loff_t *f_ps)
+{
+	struct lineevent_state *le = file->private_data;
+	struct gpioevent_data ge;
+	ssize_t bytes_read = 0;
+	ssize_t ge_size;
+	int ret;
+
+	if (!le->gdev->chip)
+		return -ENODEV;
+
+	/*
+	 * When compatible system call is being used the struct gpioevent_data,
+	 * in case of at least ia32, has different size due to the alignment
+	 * differences. Because we have first member 64 bits followed by one of
+	 * 32 bits there is no gap between them. The only difference is the
+	 * padding at the end of the data structure. Hence, we calculate the
+	 * actual sizeof() and pass this as an argument to copy_to_user() to
+	 * drop unneeded bytes from the output.
+	 */
+	if (compat_need_64bit_alignment_fixup())
+		ge_size = sizeof(struct compat_gpioeevent_data);
+	else
+		ge_size = sizeof(struct gpioevent_data);
+	if (count < ge_size)
+		return -EINVAL;
+
+	do {
+		spin_lock(&le->wait.lock);
+		if (kfifo_is_empty(&le->events)) {
+			if (bytes_read) {
+				spin_unlock(&le->wait.lock);
+				return bytes_read;
+			}
+
+			if (file->f_flags & O_NONBLOCK) {
+				spin_unlock(&le->wait.lock);
+				return -EAGAIN;
+			}
+
+			ret = wait_event_interruptible_locked(le->wait,
+					!kfifo_is_empty(&le->events));
+			if (ret) {
+				spin_unlock(&le->wait.lock);
+				return ret;
+			}
+		}
+
+		ret = kfifo_out(&le->events, &ge, 1);
+		spin_unlock(&le->wait.lock);
+		if (ret != 1) {
+			/*
+			 * This should never happen - we were holding the lock
+			 * from the moment we learned the fifo is no longer
+			 * empty until now.
+			 */
+			ret = -EIO;
+			break;
+		}
+
+		if (copy_to_user(buf + bytes_read, &ge, ge_size))
+			return -EFAULT;
+		bytes_read += ge_size;
+	} while (count >= bytes_read + ge_size);
+
+	return bytes_read;
+}
+
+static ssize_t lineevent_read(struct file *file, char __user *buf,
+			      size_t count, loff_t *f_ps)
+{
+	struct lineevent_state *le = file->private_data;
+
+	return call_read_locked(file, buf, count, f_ps, le->gdev,
+				lineevent_read_unlocked);
+}
+
+static void lineevent_free(struct lineevent_state *le)
+{
+	if (le->irq)
+		free_irq(le->irq, le);
+	if (le->desc)
+		gpiod_free(le->desc);
+	kfree(le->label);
+	put_device(&le->gdev->dev);
+	kfree(le);
+}
+
+static int lineevent_release(struct inode *inode, struct file *file)
+{
+	lineevent_free(file->private_data);
+	return 0;
+}
+
+static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd,
+				     unsigned long arg)
+{
+	struct lineevent_state *le = file->private_data;
+	void __user *ip = (void __user *)arg;
+	struct gpiohandle_data ghd;
+
+	if (!le->gdev->chip)
+		return -ENODEV;
+
+	/*
+	 * We can get the value for an event line but not set it,
+	 * because it is input by definition.
+	 */
+	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
+		int val;
+
+		memset(&ghd, 0, sizeof(ghd));
+
+		val = gpiod_get_value_cansleep(le->desc);
+		if (val < 0)
+			return val;
+		ghd.values[0] = val;
+
+		if (copy_to_user(ip, &ghd, sizeof(ghd)))
+			return -EFAULT;
+
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static long lineevent_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct lineevent_state *le = file->private_data;
+
+	return call_ioctl_locked(file, cmd, arg, le->gdev,
+				 lineevent_ioctl_unlocked);
+}
+
+#ifdef CONFIG_COMPAT
+static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations lineevent_fileops = {
+	.release = lineevent_release,
+	.read = lineevent_read,
+	.poll = lineevent_poll,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = lineevent_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = lineevent_ioctl_compat,
+#endif
+};
+
+static irqreturn_t lineevent_irq_thread(int irq, void *p)
+{
+	struct lineevent_state *le = p;
+	struct gpioevent_data ge;
+	int ret;
+
+	/* Do not leak kernel stack to userspace */
+	memset(&ge, 0, sizeof(ge));
+
+	/*
+	 * We may be running from a nested threaded interrupt in which case
+	 * we didn't get the timestamp from lineevent_irq_handler().
+	 */
+	if (!le->timestamp)
+		ge.timestamp = ktime_get_ns();
+	else
+		ge.timestamp = le->timestamp;
+
+	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
+	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+		int level = gpiod_get_value_cansleep(le->desc);
+
+		if (level)
+			/* Emit low-to-high event */
+			ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+		else
+			/* Emit high-to-low event */
+			ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+	} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
+		/* Emit low-to-high event */
+		ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+	} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+		/* Emit high-to-low event */
+		ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+	} else {
+		return IRQ_NONE;
+	}
+
+	ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
+					    1, &le->wait.lock);
+	if (ret)
+		wake_up_poll(&le->wait, EPOLLIN);
+	else
+		pr_debug_ratelimited("event FIFO is full - event dropped\n");
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t lineevent_irq_handler(int irq, void *p)
+{
+	struct lineevent_state *le = p;
+
+	/*
+	 * Just store the timestamp in hardirq context so we get it as
+	 * close in time as possible to the actual event.
+	 */
+	le->timestamp = ktime_get_ns();
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int lineevent_create(struct gpio_device *gdev, void __user *ip)
+{
+	struct gpioevent_request eventreq;
+	struct lineevent_state *le;
+	struct gpio_desc *desc;
+	struct file *file;
+	u32 offset;
+	u32 lflags;
+	u32 eflags;
+	int fd;
+	int ret;
+	int irq, irqflags = 0;
+
+	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
+		return -EFAULT;
+
+	offset = eventreq.lineoffset;
+	lflags = eventreq.handleflags;
+	eflags = eventreq.eventflags;
+
+	desc = gpiochip_get_desc(gdev->chip, offset);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	/* Return an error if a unknown flag is set */
+	if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
+	    (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
+		return -EINVAL;
+
+	/* This is just wrong: we don't look for events on output lines */
+	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* Only one bias flag can be set. */
+	if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+	     (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+	    ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+	     (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+		return -EINVAL;
+
+	le = kzalloc(sizeof(*le), GFP_KERNEL);
+	if (!le)
+		return -ENOMEM;
+	le->gdev = gdev;
+	get_device(&gdev->dev);
+
+	if (eventreq.consumer_label[0] != '\0') {
+		/* label is only initialized if consumer_label is set */
+		le->label = kstrndup(eventreq.consumer_label,
+				     sizeof(eventreq.consumer_label) - 1,
+				     GFP_KERNEL);
+		if (!le->label) {
+			ret = -ENOMEM;
+			goto out_free_le;
+		}
+	}
+
+	ret = gpiod_request_user(desc, le->label);
+	if (ret)
+		goto out_free_le;
+	le->desc = desc;
+	le->eflags = eflags;
+
+	linehandle_flags_to_desc_flags(lflags, &desc->flags);
+
+	ret = gpiod_direction_input(desc);
+	if (ret)
+		goto out_free_le;
+
+	blocking_notifier_call_chain(&desc->gdev->notifier,
+				     GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+	irq = gpiod_to_irq(desc);
+	if (irq <= 0) {
+		ret = -ENODEV;
+		goto out_free_le;
+	}
+
+	if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+	if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+	irqflags |= IRQF_ONESHOT;
+
+	INIT_KFIFO(le->events);
+	init_waitqueue_head(&le->wait);
+
+	/* Request a thread to read the events */
+	ret = request_threaded_irq(irq,
+				   lineevent_irq_handler,
+				   lineevent_irq_thread,
+				   irqflags,
+				   le->label,
+				   le);
+	if (ret)
+		goto out_free_le;
+
+	le->irq = irq;
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto out_free_le;
+	}
+
+	file = anon_inode_getfile("gpio-event",
+				  &lineevent_fileops,
+				  le,
+				  O_RDONLY | O_CLOEXEC);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_put_unused_fd;
+	}
+
+	eventreq.fd = fd;
+	if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
+		/*
+		 * fput() will trigger the release() callback, so do not go onto
+		 * the regular error cleanup path here.
+		 */
+		fput(file);
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	fd_install(fd, file);
+
+	return 0;
+
+out_put_unused_fd:
+	put_unused_fd(fd);
+out_free_le:
+	lineevent_free(le);
+	return ret;
+}
+
+static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
+				    struct gpioline_info *info_v1)
+{
+	u64 flagsv2 = info_v2->flags;
+
+	memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
+	memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
+	info_v1->line_offset = info_v2->offset;
+	info_v1->flags = 0;
+
+	if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
+		info_v1->flags |= GPIOLINE_FLAG_KERNEL;
+
+	if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
+		info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
+
+	if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
+		info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+
+	if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
+		info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
+	if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
+		info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
+
+	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
+		info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
+	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
+		info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
+	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
+		info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
+}
+
+static void gpio_v2_line_info_changed_to_v1(
+		struct gpio_v2_line_info_changed *lic_v2,
+		struct gpioline_info_changed *lic_v1)
+{
+	memset(lic_v1, 0, sizeof(*lic_v1));
+	gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
+	lic_v1->timestamp = lic_v2->timestamp_ns;
+	lic_v1->event_type = lic_v2->event_type;
+}
+
+#endif /* CONFIG_GPIO_CDEV_V1 */
+
+static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
+				  struct gpio_v2_line_info *info)
+{
+	struct gpio_chip *gc = desc->gdev->chip;
+	bool ok_for_pinctrl;
+	unsigned long flags;
+	u32 debounce_period_us;
+	unsigned int num_attrs = 0;
+
+	memset(info, 0, sizeof(*info));
+	info->offset = gpio_chip_hwgpio(desc);
+
+	/*
+	 * This function takes a mutex so we must check this before taking
+	 * the spinlock.
+	 *
+	 * FIXME: find a non-racy way to retrieve this information. Maybe a
+	 * lock common to both frameworks?
+	 */
+	ok_for_pinctrl =
+		pinctrl_gpio_can_use_line(gc->base + info->offset);
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	if (desc->name)
+		strscpy(info->name, desc->name, sizeof(info->name));
+
+	if (desc->label)
+		strscpy(info->consumer, desc->label, sizeof(info->consumer));
+
+	/*
+	 * Userspace only need to know that the kernel is using this GPIO so
+	 * it can't use it.
+	 */
+	info->flags = 0;
+	if (test_bit(FLAG_REQUESTED, &desc->flags) ||
+	    test_bit(FLAG_IS_HOGGED, &desc->flags) ||
+	    test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
+	    test_bit(FLAG_EXPORT, &desc->flags) ||
+	    test_bit(FLAG_SYSFS, &desc->flags) ||
+	    !gpiochip_line_is_valid(gc, info->offset) ||
+	    !ok_for_pinctrl)
+		info->flags |= GPIO_V2_LINE_FLAG_USED;
+
+	if (test_bit(FLAG_IS_OUT, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
+	else
+		info->flags |= GPIO_V2_LINE_FLAG_INPUT;
+
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
+
+	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
+	if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
+
+	if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
+	if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
+	if (test_bit(FLAG_PULL_UP, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
+
+	if (test_bit(FLAG_EDGE_RISING, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
+	if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
+
+	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
+	else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags))
+		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
+
+	debounce_period_us = READ_ONCE(desc->debounce_period_us);
+	if (debounce_period_us) {
+		info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
+		info->attrs[num_attrs].debounce_period_us = debounce_period_us;
+		num_attrs++;
+	}
+	info->num_attrs = num_attrs;
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+}
+
+struct gpio_chardev_data {
+	struct gpio_device *gdev;
+	wait_queue_head_t wait;
+	DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
+	struct notifier_block lineinfo_changed_nb;
+	unsigned long *watched_lines;
+#ifdef CONFIG_GPIO_CDEV_V1
+	atomic_t watch_abi_version;
+#endif
+};
+
+static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
+{
+	struct gpio_device *gdev = cdev->gdev;
+	struct gpiochip_info chipinfo;
+
+	memset(&chipinfo, 0, sizeof(chipinfo));
+
+	strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
+	strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
+	chipinfo.lines = gdev->ngpio;
+	if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
+		return -EFAULT;
+	return 0;
+}
+
+#ifdef CONFIG_GPIO_CDEV_V1
+/*
+ * returns 0 if the versions match, else the previously selected ABI version
+ */
+static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
+				       unsigned int version)
+{
+	int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
+
+	if (abiv == version)
+		return 0;
+
+	return abiv;
+}
+
+static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
+			   bool watch)
+{
+	struct gpio_desc *desc;
+	struct gpioline_info lineinfo;
+	struct gpio_v2_line_info lineinfo_v2;
+
+	if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+		return -EFAULT;
+
+	/* this doubles as a range check on line_offset */
+	desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	if (watch) {
+		if (lineinfo_ensure_abi_version(cdev, 1))
+			return -EPERM;
+
+		if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
+			return -EBUSY;
+	}
+
+	gpio_desc_to_lineinfo(desc, &lineinfo_v2);
+	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
+
+	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
+		if (watch)
+			clear_bit(lineinfo.line_offset, cdev->watched_lines);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+#endif
+
+static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
+			bool watch)
+{
+	struct gpio_desc *desc;
+	struct gpio_v2_line_info lineinfo;
+
+	if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+		return -EFAULT;
+
+	if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
+		return -EINVAL;
+
+	desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	if (watch) {
+#ifdef CONFIG_GPIO_CDEV_V1
+		if (lineinfo_ensure_abi_version(cdev, 2))
+			return -EPERM;
+#endif
+		if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
+			return -EBUSY;
+	}
+	gpio_desc_to_lineinfo(desc, &lineinfo);
+
+	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
+		if (watch)
+			clear_bit(lineinfo.offset, cdev->watched_lines);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
+{
+	__u32 offset;
+
+	if (copy_from_user(&offset, ip, sizeof(offset)))
+		return -EFAULT;
+
+	if (offset >= cdev->gdev->ngpio)
+		return -EINVAL;
+
+	if (!test_and_clear_bit(offset, cdev->watched_lines))
+		return -EBUSY;
+
+	return 0;
+}
+
+static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+	struct gpio_device *gdev = cdev->gdev;
+	void __user *ip = (void __user *)arg;
+
+	/* We fail any subsequent ioctl():s when the chip is gone */
+	if (!gdev->chip)
+		return -ENODEV;
+
+	/* Fill in the struct and pass to userspace */
+	switch (cmd) {
+	case GPIO_GET_CHIPINFO_IOCTL:
+		return chipinfo_get(cdev, ip);
+#ifdef CONFIG_GPIO_CDEV_V1
+	case GPIO_GET_LINEHANDLE_IOCTL:
+		return linehandle_create(gdev, ip);
+	case GPIO_GET_LINEEVENT_IOCTL:
+		return lineevent_create(gdev, ip);
+	case GPIO_GET_LINEINFO_IOCTL:
+		return lineinfo_get_v1(cdev, ip, false);
+	case GPIO_GET_LINEINFO_WATCH_IOCTL:
+		return lineinfo_get_v1(cdev, ip, true);
+#endif /* CONFIG_GPIO_CDEV_V1 */
+	case GPIO_V2_GET_LINEINFO_IOCTL:
+		return lineinfo_get(cdev, ip, false);
+	case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
+		return lineinfo_get(cdev, ip, true);
+	case GPIO_V2_GET_LINE_IOCTL:
+		return linereq_create(gdev, ip);
+	case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
+		return lineinfo_unwatch(cdev, ip);
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * gpio_ioctl() - ioctl handler for the GPIO chardev
+ */
+static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+
+	return call_ioctl_locked(file, cmd, arg, cdev->gdev,
+				 gpio_ioctl_unlocked);
+}
+
+#ifdef CONFIG_COMPAT
+static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static struct gpio_chardev_data *
+to_gpio_chardev_data(struct notifier_block *nb)
+{
+	return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
+}
+
+static int lineinfo_changed_notify(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
+	struct gpio_v2_line_info_changed chg;
+	struct gpio_desc *desc = data;
+	int ret;
+
+	if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
+		return NOTIFY_DONE;
+
+	memset(&chg, 0, sizeof(chg));
+	chg.event_type = action;
+	chg.timestamp_ns = ktime_get_ns();
+	gpio_desc_to_lineinfo(desc, &chg.info);
+
+	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
+	if (ret)
+		wake_up_poll(&cdev->wait, EPOLLIN);
+	else
+		pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
+
+	return NOTIFY_OK;
+}
+
+static __poll_t lineinfo_watch_poll_unlocked(struct file *file,
+					     struct poll_table_struct *pollt)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+	__poll_t events = 0;
+
+	if (!cdev->gdev->chip)
+		return EPOLLHUP | EPOLLERR;
+
+	poll_wait(file, &cdev->wait, pollt);
+
+	if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
+						 &cdev->wait.lock))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static __poll_t lineinfo_watch_poll(struct file *file,
+				    struct poll_table_struct *pollt)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+
+	return call_poll_locked(file, pollt, cdev->gdev,
+				lineinfo_watch_poll_unlocked);
+}
+
+static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf,
+					    size_t count, loff_t *off)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+	struct gpio_v2_line_info_changed event;
+	ssize_t bytes_read = 0;
+	int ret;
+	size_t event_size;
+
+	if (!cdev->gdev->chip)
+		return -ENODEV;
+
+#ifndef CONFIG_GPIO_CDEV_V1
+	event_size = sizeof(struct gpio_v2_line_info_changed);
+	if (count < event_size)
+		return -EINVAL;
+#endif
+
+	do {
+		spin_lock(&cdev->wait.lock);
+		if (kfifo_is_empty(&cdev->events)) {
+			if (bytes_read) {
+				spin_unlock(&cdev->wait.lock);
+				return bytes_read;
+			}
+
+			if (file->f_flags & O_NONBLOCK) {
+				spin_unlock(&cdev->wait.lock);
+				return -EAGAIN;
+			}
+
+			ret = wait_event_interruptible_locked(cdev->wait,
+					!kfifo_is_empty(&cdev->events));
+			if (ret) {
+				spin_unlock(&cdev->wait.lock);
+				return ret;
+			}
+		}
+#ifdef CONFIG_GPIO_CDEV_V1
+		/* must be after kfifo check so watch_abi_version is set */
+		if (atomic_read(&cdev->watch_abi_version) == 2)
+			event_size = sizeof(struct gpio_v2_line_info_changed);
+		else
+			event_size = sizeof(struct gpioline_info_changed);
+		if (count < event_size) {
+			spin_unlock(&cdev->wait.lock);
+			return -EINVAL;
+		}
+#endif
+		ret = kfifo_out(&cdev->events, &event, 1);
+		spin_unlock(&cdev->wait.lock);
+		if (ret != 1) {
+			ret = -EIO;
+			break;
+			/* We should never get here. See lineevent_read(). */
+		}
+
+#ifdef CONFIG_GPIO_CDEV_V1
+		if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
+			if (copy_to_user(buf + bytes_read, &event, event_size))
+				return -EFAULT;
+		} else {
+			struct gpioline_info_changed event_v1;
+
+			gpio_v2_line_info_changed_to_v1(&event, &event_v1);
+			if (copy_to_user(buf + bytes_read, &event_v1,
+					 event_size))
+				return -EFAULT;
+		}
+#else
+		if (copy_to_user(buf + bytes_read, &event, event_size))
+			return -EFAULT;
+#endif
+		bytes_read += event_size;
+	} while (count >= bytes_read + sizeof(event));
+
+	return bytes_read;
+}
+
+static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
+				   size_t count, loff_t *off)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+
+	return call_read_locked(file, buf, count, off, cdev->gdev,
+				lineinfo_watch_read_unlocked);
+}
+
+/**
+ * gpio_chrdev_open() - open the chardev for ioctl operations
+ * @inode: inode for this chardev
+ * @file: file struct for storing private data
+ * Returns 0 on success
+ */
+static int gpio_chrdev_open(struct inode *inode, struct file *file)
+{
+	struct gpio_device *gdev = container_of(inode->i_cdev,
+						struct gpio_device, chrdev);
+	struct gpio_chardev_data *cdev;
+	int ret = -ENOMEM;
+
+	down_read(&gdev->sem);
+
+	/* Fail on open if the backing gpiochip is gone */
+	if (!gdev->chip) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
+	if (!cdev)
+		goto out_unlock;
+
+	cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
+	if (!cdev->watched_lines)
+		goto out_free_cdev;
+
+	init_waitqueue_head(&cdev->wait);
+	INIT_KFIFO(cdev->events);
+	cdev->gdev = gdev;
+
+	cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
+	ret = blocking_notifier_chain_register(&gdev->notifier,
+					       &cdev->lineinfo_changed_nb);
+	if (ret)
+		goto out_free_bitmap;
+
+	get_device(&gdev->dev);
+	file->private_data = cdev;
+
+	ret = nonseekable_open(inode, file);
+	if (ret)
+		goto out_unregister_notifier;
+
+	up_read(&gdev->sem);
+
+	return ret;
+
+out_unregister_notifier:
+	blocking_notifier_chain_unregister(&gdev->notifier,
+					   &cdev->lineinfo_changed_nb);
+out_free_bitmap:
+	bitmap_free(cdev->watched_lines);
+out_free_cdev:
+	kfree(cdev);
+out_unlock:
+	up_read(&gdev->sem);
+	return ret;
+}
+
+/**
+ * gpio_chrdev_release() - close chardev after ioctl operations
+ * @inode: inode for this chardev
+ * @file: file struct for storing private data
+ * Returns 0 on success
+ */
+static int gpio_chrdev_release(struct inode *inode, struct file *file)
+{
+	struct gpio_chardev_data *cdev = file->private_data;
+	struct gpio_device *gdev = cdev->gdev;
+
+	bitmap_free(cdev->watched_lines);
+	blocking_notifier_chain_unregister(&gdev->notifier,
+					   &cdev->lineinfo_changed_nb);
+	put_device(&gdev->dev);
+	kfree(cdev);
+
+	return 0;
+}
+
+static const struct file_operations gpio_fileops = {
+	.release = gpio_chrdev_release,
+	.open = gpio_chrdev_open,
+	.poll = lineinfo_watch_poll,
+	.read = lineinfo_watch_read,
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.unlocked_ioctl = gpio_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = gpio_ioctl_compat,
+#endif
+};
+
+int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+{
+	int ret;
+
+	cdev_init(&gdev->chrdev, &gpio_fileops);
+	gdev->chrdev.owner = THIS_MODULE;
+	gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
+
+	ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
+	if (ret)
+		return ret;
+
+	chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
+		 MAJOR(devt), gdev->id);
+
+	return 0;
+}
+
+void gpiolib_cdev_unregister(struct gpio_device *gdev)
+{
+	cdev_device_del(&gdev->chrdev, &gdev->dev);
+}