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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/gpio/gpio-aggregator.c | |
parent | Initial commit. (diff) | |
download | linux-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.c | 636 |
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"); |