summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-aggregator.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/gpio/gpio-aggregator.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/gpio/gpio-aggregator.c')
-rw-r--r--drivers/gpio/gpio-aggregator.c636
1 files changed, 636 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c
new file mode 100644
index 0000000000..38e0fff9af
--- /dev/null
+++ b/drivers/gpio/gpio-aggregator.c
@@ -0,0 +1,636 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// GPIO Aggregator
+//
+// Copyright (C) 2019-2020 Glider bv
+
+#define DRV_NAME "gpio-aggregator"
+#define pr_fmt(fmt) DRV_NAME ": " fmt
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/overflow.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+
+#define AGGREGATOR_MAX_GPIOS 512
+
+/*
+ * GPIO Aggregator sysfs interface
+ */
+
+struct gpio_aggregator {
+ struct gpiod_lookup_table *lookups;
+ struct platform_device *pdev;
+ char args[];
+};
+
+static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */
+static DEFINE_IDR(gpio_aggregator_idr);
+
+static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key,
+ int hwnum, unsigned int *n)
+{
+ struct gpiod_lookup_table *lookups;
+
+ lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2),
+ GFP_KERNEL);
+ if (!lookups)
+ return -ENOMEM;
+
+ lookups->table[*n] = GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0);
+
+ (*n)++;
+ memset(&lookups->table[*n], 0, sizeof(lookups->table[*n]));
+
+ aggr->lookups = lookups;
+ return 0;
+}
+
+static int aggr_parse(struct gpio_aggregator *aggr)
+{
+ char *args = skip_spaces(aggr->args);
+ char *name, *offsets, *p;
+ unsigned long *bitmap;
+ unsigned int i, n = 0;
+ int error = 0;
+
+ bitmap = bitmap_alloc(AGGREGATOR_MAX_GPIOS, GFP_KERNEL);
+ if (!bitmap)
+ return -ENOMEM;
+
+ args = next_arg(args, &name, &p);
+ while (*args) {
+ args = next_arg(args, &offsets, &p);
+
+ p = get_options(offsets, 0, &error);
+ if (error == 0 || *p) {
+ /* Named GPIO line */
+ error = aggr_add_gpio(aggr, name, U16_MAX, &n);
+ if (error)
+ goto free_bitmap;
+
+ name = offsets;
+ continue;
+ }
+
+ /* GPIO chip + offset(s) */
+ error = bitmap_parselist(offsets, bitmap, AGGREGATOR_MAX_GPIOS);
+ if (error) {
+ pr_err("Cannot parse %s: %d\n", offsets, error);
+ goto free_bitmap;
+ }
+
+ for_each_set_bit(i, bitmap, AGGREGATOR_MAX_GPIOS) {
+ error = aggr_add_gpio(aggr, name, i, &n);
+ if (error)
+ goto free_bitmap;
+ }
+
+ args = next_arg(args, &name, &p);
+ }
+
+ if (!n) {
+ pr_err("No GPIOs specified\n");
+ error = -EINVAL;
+ }
+
+free_bitmap:
+ bitmap_free(bitmap);
+ return error;
+}
+
+static ssize_t new_device_store(struct device_driver *driver, const char *buf,
+ size_t count)
+{
+ struct gpio_aggregator *aggr;
+ struct platform_device *pdev;
+ int res, id;
+
+ /* kernfs guarantees string termination, so count + 1 is safe */
+ aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL);
+ if (!aggr)
+ return -ENOMEM;
+
+ memcpy(aggr->args, buf, count + 1);
+
+ aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1),
+ GFP_KERNEL);
+ if (!aggr->lookups) {
+ res = -ENOMEM;
+ goto free_ga;
+ }
+
+ mutex_lock(&gpio_aggregator_lock);
+ id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL);
+ mutex_unlock(&gpio_aggregator_lock);
+
+ if (id < 0) {
+ res = id;
+ goto free_table;
+ }
+
+ aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id);
+ if (!aggr->lookups->dev_id) {
+ res = -ENOMEM;
+ goto remove_idr;
+ }
+
+ res = aggr_parse(aggr);
+ if (res)
+ goto free_dev_id;
+
+ gpiod_add_lookup_table(aggr->lookups);
+
+ pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0);
+ if (IS_ERR(pdev)) {
+ res = PTR_ERR(pdev);
+ goto remove_table;
+ }
+
+ aggr->pdev = pdev;
+ return count;
+
+remove_table:
+ gpiod_remove_lookup_table(aggr->lookups);
+free_dev_id:
+ kfree(aggr->lookups->dev_id);
+remove_idr:
+ mutex_lock(&gpio_aggregator_lock);
+ idr_remove(&gpio_aggregator_idr, id);
+ mutex_unlock(&gpio_aggregator_lock);
+free_table:
+ kfree(aggr->lookups);
+free_ga:
+ kfree(aggr);
+ return res;
+}
+
+static DRIVER_ATTR_WO(new_device);
+
+static void gpio_aggregator_free(struct gpio_aggregator *aggr)
+{
+ platform_device_unregister(aggr->pdev);
+ gpiod_remove_lookup_table(aggr->lookups);
+ kfree(aggr->lookups->dev_id);
+ kfree(aggr->lookups);
+ kfree(aggr);
+}
+
+static ssize_t delete_device_store(struct device_driver *driver,
+ const char *buf, size_t count)
+{
+ struct gpio_aggregator *aggr;
+ unsigned int id;
+ int error;
+
+ if (!str_has_prefix(buf, DRV_NAME "."))
+ return -EINVAL;
+
+ error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id);
+ if (error)
+ return error;
+
+ mutex_lock(&gpio_aggregator_lock);
+ aggr = idr_remove(&gpio_aggregator_idr, id);
+ mutex_unlock(&gpio_aggregator_lock);
+ if (!aggr)
+ return -ENOENT;
+
+ gpio_aggregator_free(aggr);
+ return count;
+}
+static DRIVER_ATTR_WO(delete_device);
+
+static struct attribute *gpio_aggregator_attrs[] = {
+ &driver_attr_new_device.attr,
+ &driver_attr_delete_device.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(gpio_aggregator);
+
+static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data)
+{
+ gpio_aggregator_free(p);
+ return 0;
+}
+
+static void __exit gpio_aggregator_remove_all(void)
+{
+ mutex_lock(&gpio_aggregator_lock);
+ idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL);
+ idr_destroy(&gpio_aggregator_idr);
+ mutex_unlock(&gpio_aggregator_lock);
+}
+
+
+/*
+ * GPIO Forwarder
+ */
+
+struct gpiochip_fwd_timing {
+ u32 ramp_up_us;
+ u32 ramp_down_us;
+};
+
+struct gpiochip_fwd {
+ struct gpio_chip chip;
+ struct gpio_desc **descs;
+ union {
+ struct mutex mlock; /* protects tmp[] if can_sleep */
+ spinlock_t slock; /* protects tmp[] if !can_sleep */
+ };
+ struct gpiochip_fwd_timing *delay_timings;
+ unsigned long tmp[]; /* values and descs for multiple ops */
+};
+
+#define fwd_tmp_values(fwd) &(fwd)->tmp[0]
+#define fwd_tmp_descs(fwd) (void *)&(fwd)->tmp[BITS_TO_LONGS((fwd)->chip.ngpio)]
+
+#define fwd_tmp_size(ngpios) (BITS_TO_LONGS((ngpios)) + (ngpios))
+
+static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return gpiod_get_direction(fwd->descs[offset]);
+}
+
+static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return gpiod_direction_input(fwd->descs[offset]);
+}
+
+static int gpio_fwd_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return gpiod_direction_output(fwd->descs[offset], value);
+}
+
+static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return chip->can_sleep ? gpiod_get_value_cansleep(fwd->descs[offset])
+ : gpiod_get_value(fwd->descs[offset]);
+}
+
+static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct gpio_desc **descs = fwd_tmp_descs(fwd);
+ unsigned long *values = fwd_tmp_values(fwd);
+ unsigned int i, j = 0;
+ int error;
+
+ bitmap_clear(values, 0, fwd->chip.ngpio);
+ for_each_set_bit(i, mask, fwd->chip.ngpio)
+ descs[j++] = fwd->descs[i];
+
+ if (fwd->chip.can_sleep)
+ error = gpiod_get_array_value_cansleep(j, descs, NULL, values);
+ else
+ error = gpiod_get_array_value(j, descs, NULL, values);
+ if (error)
+ return error;
+
+ j = 0;
+ for_each_set_bit(i, mask, fwd->chip.ngpio)
+ __assign_bit(i, bits, test_bit(j++, values));
+
+ return 0;
+}
+
+static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+ unsigned long flags;
+ int error;
+
+ if (chip->can_sleep) {
+ mutex_lock(&fwd->mlock);
+ error = gpio_fwd_get_multiple(fwd, mask, bits);
+ mutex_unlock(&fwd->mlock);
+ } else {
+ spin_lock_irqsave(&fwd->slock, flags);
+ error = gpio_fwd_get_multiple(fwd, mask, bits);
+ spin_unlock_irqrestore(&fwd->slock, flags);
+ }
+
+ return error;
+}
+
+static void gpio_fwd_delay(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+ const struct gpiochip_fwd_timing *delay_timings;
+ bool is_active_low = gpiod_is_active_low(fwd->descs[offset]);
+ u32 delay_us;
+
+ delay_timings = &fwd->delay_timings[offset];
+ if ((!is_active_low && value) || (is_active_low && !value))
+ delay_us = delay_timings->ramp_up_us;
+ else
+ delay_us = delay_timings->ramp_down_us;
+ if (!delay_us)
+ return;
+
+ if (chip->can_sleep)
+ fsleep(delay_us);
+ else
+ udelay(delay_us);
+}
+
+static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ if (chip->can_sleep)
+ gpiod_set_value_cansleep(fwd->descs[offset], value);
+ else
+ gpiod_set_value(fwd->descs[offset], value);
+
+ if (fwd->delay_timings)
+ gpio_fwd_delay(chip, offset, value);
+}
+
+static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct gpio_desc **descs = fwd_tmp_descs(fwd);
+ unsigned long *values = fwd_tmp_values(fwd);
+ unsigned int i, j = 0;
+
+ for_each_set_bit(i, mask, fwd->chip.ngpio) {
+ __assign_bit(j, values, test_bit(i, bits));
+ descs[j++] = fwd->descs[i];
+ }
+
+ if (fwd->chip.can_sleep)
+ gpiod_set_array_value_cansleep(j, descs, NULL, values);
+ else
+ gpiod_set_array_value(j, descs, NULL, values);
+}
+
+static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+ unsigned long flags;
+
+ if (chip->can_sleep) {
+ mutex_lock(&fwd->mlock);
+ gpio_fwd_set_multiple(fwd, mask, bits);
+ mutex_unlock(&fwd->mlock);
+ } else {
+ spin_lock_irqsave(&fwd->slock, flags);
+ gpio_fwd_set_multiple(fwd, mask, bits);
+ spin_unlock_irqrestore(&fwd->slock, flags);
+ }
+}
+
+static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
+ unsigned long config)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return gpiod_set_config(fwd->descs[offset], config);
+}
+
+static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+
+ return gpiod_to_irq(fwd->descs[offset]);
+}
+
+/*
+ * The GPIO delay provides a way to configure platform specific delays
+ * for the GPIO ramp-up or ramp-down delays. This can serve the following
+ * purposes:
+ * - Open-drain output using an RC filter
+ */
+#define FWD_FEATURE_DELAY BIT(0)
+
+#ifdef CONFIG_OF_GPIO
+static int gpiochip_fwd_delay_of_xlate(struct gpio_chip *chip,
+ const struct of_phandle_args *gpiospec,
+ u32 *flags)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+ struct gpiochip_fwd_timing *timings;
+ u32 line;
+
+ if (gpiospec->args_count != chip->of_gpio_n_cells)
+ return -EINVAL;
+
+ line = gpiospec->args[0];
+ if (line >= chip->ngpio)
+ return -EINVAL;
+
+ timings = &fwd->delay_timings[line];
+ timings->ramp_up_us = gpiospec->args[1];
+ timings->ramp_down_us = gpiospec->args[2];
+
+ return line;
+}
+
+static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
+ struct gpiochip_fwd *fwd)
+{
+ fwd->delay_timings = devm_kcalloc(dev, chip->ngpio,
+ sizeof(*fwd->delay_timings),
+ GFP_KERNEL);
+ if (!fwd->delay_timings)
+ return -ENOMEM;
+
+ chip->of_xlate = gpiochip_fwd_delay_of_xlate;
+ chip->of_gpio_n_cells = 3;
+
+ return 0;
+}
+#else
+static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
+ struct gpiochip_fwd *fwd)
+{
+ return 0;
+}
+#endif /* !CONFIG_OF_GPIO */
+
+/**
+ * gpiochip_fwd_create() - Create a new GPIO forwarder
+ * @dev: Parent device pointer
+ * @ngpios: Number of GPIOs in the forwarder.
+ * @descs: Array containing the GPIO descriptors to forward to.
+ * This array must contain @ngpios entries, and must not be deallocated
+ * before the forwarder has been destroyed again.
+ * @features: Bitwise ORed features as defined with FWD_FEATURE_*.
+ *
+ * This function creates a new gpiochip, which forwards all GPIO operations to
+ * the passed GPIO descriptors.
+ *
+ * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
+ * code on failure.
+ */
+static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
+ unsigned int ngpios,
+ struct gpio_desc *descs[],
+ unsigned long features)
+{
+ const char *label = dev_name(dev);
+ struct gpiochip_fwd *fwd;
+ struct gpio_chip *chip;
+ unsigned int i;
+ int error;
+
+ fwd = devm_kzalloc(dev, struct_size(fwd, tmp, fwd_tmp_size(ngpios)),
+ GFP_KERNEL);
+ if (!fwd)
+ return ERR_PTR(-ENOMEM);
+
+ chip = &fwd->chip;
+
+ /*
+ * If any of the GPIO lines are sleeping, then the entire forwarder
+ * will be sleeping.
+ * If any of the chips support .set_config(), then the forwarder will
+ * support setting configs.
+ */
+ for (i = 0; i < ngpios; i++) {
+ struct gpio_chip *parent = gpiod_to_chip(descs[i]);
+
+ dev_dbg(dev, "%u => gpio %d irq %d\n", i,
+ desc_to_gpio(descs[i]), gpiod_to_irq(descs[i]));
+
+ if (gpiod_cansleep(descs[i]))
+ chip->can_sleep = true;
+ if (parent && parent->set_config)
+ chip->set_config = gpio_fwd_set_config;
+ }
+
+ chip->label = label;
+ chip->parent = dev;
+ chip->owner = THIS_MODULE;
+ chip->get_direction = gpio_fwd_get_direction;
+ chip->direction_input = gpio_fwd_direction_input;
+ chip->direction_output = gpio_fwd_direction_output;
+ chip->get = gpio_fwd_get;
+ chip->get_multiple = gpio_fwd_get_multiple_locked;
+ chip->set = gpio_fwd_set;
+ chip->set_multiple = gpio_fwd_set_multiple_locked;
+ chip->to_irq = gpio_fwd_to_irq;
+ chip->base = -1;
+ chip->ngpio = ngpios;
+ fwd->descs = descs;
+
+ if (chip->can_sleep)
+ mutex_init(&fwd->mlock);
+ else
+ spin_lock_init(&fwd->slock);
+
+ if (features & FWD_FEATURE_DELAY) {
+ error = gpiochip_fwd_setup_delay_line(dev, chip, fwd);
+ if (error)
+ return ERR_PTR(error);
+ }
+
+ error = devm_gpiochip_add_data(dev, chip, fwd);
+ if (error)
+ return ERR_PTR(error);
+
+ return fwd;
+}
+
+
+/*
+ * GPIO Aggregator platform device
+ */
+
+static int gpio_aggregator_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct gpio_desc **descs;
+ struct gpiochip_fwd *fwd;
+ unsigned long features;
+ int i, n;
+
+ n = gpiod_count(dev, NULL);
+ if (n < 0)
+ return n;
+
+ descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
+ if (!descs)
+ return -ENOMEM;
+
+ for (i = 0; i < n; i++) {
+ descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
+ if (IS_ERR(descs[i]))
+ return PTR_ERR(descs[i]);
+ }
+
+ features = (uintptr_t)device_get_match_data(dev);
+ fwd = gpiochip_fwd_create(dev, n, descs, features);
+ if (IS_ERR(fwd))
+ return PTR_ERR(fwd);
+
+ platform_set_drvdata(pdev, fwd);
+ return 0;
+}
+
+static const struct of_device_id gpio_aggregator_dt_ids[] = {
+ {
+ .compatible = "gpio-delay",
+ .data = (void *)FWD_FEATURE_DELAY,
+ },
+ /*
+ * Add GPIO-operated devices controlled from userspace below,
+ * or use "driver_override" in sysfs.
+ */
+ {}
+};
+MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids);
+
+static struct platform_driver gpio_aggregator_driver = {
+ .probe = gpio_aggregator_probe,
+ .driver = {
+ .name = DRV_NAME,
+ .groups = gpio_aggregator_groups,
+ .of_match_table = gpio_aggregator_dt_ids,
+ },
+};
+
+static int __init gpio_aggregator_init(void)
+{
+ return platform_driver_register(&gpio_aggregator_driver);
+}
+module_init(gpio_aggregator_init);
+
+static void __exit gpio_aggregator_exit(void)
+{
+ gpio_aggregator_remove_all();
+ platform_driver_unregister(&gpio_aggregator_driver);
+}
+module_exit(gpio_aggregator_exit);
+
+MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
+MODULE_DESCRIPTION("GPIO Aggregator");
+MODULE_LICENSE("GPL v2");