diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 2391 |
1 files changed, 2391 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c new file mode 100644 index 000000000..40d0196d8 --- /dev/null +++ b/drivers/gpio/gpiolib-cdev.c @@ -0,0 +1,2391 @@ +// 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 <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. + */ + +/* + * 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(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; + } +} + +#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(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 + */ +struct line { + struct gpio_desc *desc; + /* + * -- edge detector specific fields -- + */ + struct linereq *req; + unsigned int irq; + u64 eflags; + /* + * 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; +}; + +/** + * 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_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_BIAS_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 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 = ktime_get_ns(); + if (lr->num_lines != 1) + line->req_seqno = atomic_inc_return(&lr->seqno); + } + line->timestamp_ns = 0; + + if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING | + GPIO_V2_LINE_FLAG_EDGE_FALLING)) { + int level = gpiod_get_value_cansleep(line->desc); + + if (level) + /* Emit low-to-high event */ + le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; + else + /* Emit high-to-low event */ + le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; + } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) { + /* Emit low-to-high event */ + le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; + } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) { + /* Emit high-to-low event */ + le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; + } else { + 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 = ktime_get_ns(); + + 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; + int level; + + 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 -- */ + if (!line->eflags) + return; + + /* switch from physical level to logical - if they differ */ + if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) + level = !level; + + /* ignore edges that are not being monitored */ + if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || + ((line->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 = ktime_get_ns(); + le.offset = gpio_chip_hwgpio(line->desc); + line->line_seqno++; + le.line_seqno = line->line_seqno; + le.seqno = (lr->num_lines == 1) ? + le.line_seqno : atomic_inc_return(&lr->seqno); + + if (level) + /* Emit low-to-high event */ + le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; + else + /* Emit high-to-low event */ + le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; + + 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; + + irq = gpiod_to_irq(line->desc); + if (irq < 0) + return -ENXIO; + + WRITE_ONCE(line->level, level); + irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; + ret = request_irq(irq, debounce_irq_handler, irqflags, + line->req->label, line); + if (ret) + return ret; + + WRITE_ONCE(line->sw_debounced, 1); + line->irq = irq; + } + 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; + } + + cancel_delayed_work_sync(&line->work); + WRITE_ONCE(line->sw_debounced, 0); + line->eflags = 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 eflags) +{ + u32 debounce_period_us; + unsigned long irqflags = 0; + int irq, ret; + + if (eflags && !kfifo_initialized(&line->req->events)) { + ret = kfifo_alloc(&line->req->events, + line->req->event_buffer_size, GFP_KERNEL); + if (ret) + return ret; + } + line->eflags = eflags; + 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; + + 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 eflags, bool polarity_change) +{ + unsigned int debounce_period_us = + gpio_v2_line_config_debounce_period(lc, line_idx); + + if ((line->eflags == eflags) && !polarity_change && + (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)) { + line->eflags = eflags; + 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)) || + (!debounce_period_us && READ_ONCE(line->sw_debounced))) + edge_detector_stop(line); + + return edge_detector_setup(line, lc, line_idx, eflags); +} + +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; + + /* + * 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; + + /* 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); +} + +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; + unsigned int i; + u64 flags; + bool polarity_change; + int ret; + + for (i = 0; i < lr->num_lines; i++) { + desc = lr->lines[i].desc; + flags = gpio_v2_line_config_flags(lc, i); + polarity_change = + (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != + ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); + + gpio_v2_line_config_flags_to_desc_flags(flags, &desc->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(&lr->lines[i]); + 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(&lr->lines[i], lc, i, + flags & GPIO_V2_LINE_EDGE_FLAGS, + polarity_change); + if (ret) + return ret; + } + + 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(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; + } +} + +#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(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 ssize_t linereq_read(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 void linereq_free(struct linereq *lr) +{ + unsigned int i; + + for (i = 0; i < lr->num_lines; i++) { + edge_detector_stop(&lr->lines[i]); + if (lr->lines[i].desc) + 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; +} + +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 +}; + +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; + 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(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; + + /* + * 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, + flags & GPIO_V2_LINE_EDGE_FLAGS); + if (ret) + goto out_free_linereq; + } + + 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(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 ssize_t lineevent_get_size(void) +{ +#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) + /* i386 has no padding after 'id' */ + if (in_ia32_syscall()) { + struct compat_gpioeevent_data { + compat_u64 timestamp; + u32 id; + }; + + return sizeof(struct compat_gpioeevent_data); + } +#endif + return sizeof(struct gpioevent_data); +} + +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; + 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. + */ + ge_size = lineevent_get_size(); + 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 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(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; +} + +#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(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) || + !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; + + 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; +} + +/* + * 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; + 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; + } +} + +#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(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 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; + 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; +} + +/** + * 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; + + /* Fail on open if the backing gpiochip is gone */ + if (!gdev->chip) + return -ENODEV; + + cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); + if (!cdev) + return -ENOMEM; + + 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; + + 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); + 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); +} |