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520 lines
12 KiB
520 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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// |
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// GPIO Aggregator |
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// |
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// Copyright (C) 2019-2020 Glider bv |
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#define DRV_NAME "gpio-aggregator" |
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#define pr_fmt(fmt) DRV_NAME ": " fmt |
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#include <linux/bitmap.h> |
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#include <linux/bitops.h> |
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#include <linux/ctype.h> |
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#include <linux/gpio.h> |
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#include <linux/gpio/consumer.h> |
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#include <linux/gpio/driver.h> |
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#include <linux/gpio/machine.h> |
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#include <linux/idr.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/overflow.h> |
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#include <linux/platform_device.h> |
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#include <linux/spinlock.h> |
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#include <linux/string.h> |
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/* |
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* GPIO Aggregator sysfs interface |
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*/ |
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struct gpio_aggregator { |
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struct gpiod_lookup_table *lookups; |
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struct platform_device *pdev; |
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char args[]; |
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}; |
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static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */ |
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static DEFINE_IDR(gpio_aggregator_idr); |
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static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key, |
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int hwnum, unsigned int *n) |
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{ |
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struct gpiod_lookup_table *lookups; |
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lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2), |
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GFP_KERNEL); |
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if (!lookups) |
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return -ENOMEM; |
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lookups->table[*n] = GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0); |
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(*n)++; |
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memset(&lookups->table[*n], 0, sizeof(lookups->table[*n])); |
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aggr->lookups = lookups; |
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return 0; |
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} |
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static int aggr_parse(struct gpio_aggregator *aggr) |
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{ |
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char *args = skip_spaces(aggr->args); |
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char *name, *offsets, *p; |
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unsigned long *bitmap; |
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unsigned int i, n = 0; |
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int error = 0; |
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bitmap = bitmap_alloc(ARCH_NR_GPIOS, GFP_KERNEL); |
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if (!bitmap) |
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return -ENOMEM; |
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args = next_arg(args, &name, &p); |
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while (*args) { |
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args = next_arg(args, &offsets, &p); |
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p = get_options(offsets, 0, &error); |
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if (error == 0 || *p) { |
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/* Named GPIO line */ |
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error = aggr_add_gpio(aggr, name, U16_MAX, &n); |
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if (error) |
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goto free_bitmap; |
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name = offsets; |
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continue; |
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} |
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/* GPIO chip + offset(s) */ |
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error = bitmap_parselist(offsets, bitmap, ARCH_NR_GPIOS); |
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if (error) { |
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pr_err("Cannot parse %s: %d\n", offsets, error); |
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goto free_bitmap; |
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} |
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for_each_set_bit(i, bitmap, ARCH_NR_GPIOS) { |
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error = aggr_add_gpio(aggr, name, i, &n); |
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if (error) |
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goto free_bitmap; |
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} |
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args = next_arg(args, &name, &p); |
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} |
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if (!n) { |
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pr_err("No GPIOs specified\n"); |
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error = -EINVAL; |
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} |
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free_bitmap: |
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bitmap_free(bitmap); |
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return error; |
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} |
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static ssize_t new_device_store(struct device_driver *driver, const char *buf, |
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size_t count) |
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{ |
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struct gpio_aggregator *aggr; |
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struct platform_device *pdev; |
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int res, id; |
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/* kernfs guarantees string termination, so count + 1 is safe */ |
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aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL); |
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if (!aggr) |
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return -ENOMEM; |
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memcpy(aggr->args, buf, count + 1); |
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aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1), |
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GFP_KERNEL); |
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if (!aggr->lookups) { |
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res = -ENOMEM; |
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goto free_ga; |
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} |
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mutex_lock(&gpio_aggregator_lock); |
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id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL); |
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mutex_unlock(&gpio_aggregator_lock); |
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if (id < 0) { |
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res = id; |
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goto free_table; |
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} |
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aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id); |
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if (!aggr->lookups->dev_id) { |
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res = -ENOMEM; |
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goto remove_idr; |
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} |
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res = aggr_parse(aggr); |
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if (res) |
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goto free_dev_id; |
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gpiod_add_lookup_table(aggr->lookups); |
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pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0); |
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if (IS_ERR(pdev)) { |
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res = PTR_ERR(pdev); |
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goto remove_table; |
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} |
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aggr->pdev = pdev; |
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return count; |
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remove_table: |
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gpiod_remove_lookup_table(aggr->lookups); |
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free_dev_id: |
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kfree(aggr->lookups->dev_id); |
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remove_idr: |
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mutex_lock(&gpio_aggregator_lock); |
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idr_remove(&gpio_aggregator_idr, id); |
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mutex_unlock(&gpio_aggregator_lock); |
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free_table: |
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kfree(aggr->lookups); |
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free_ga: |
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kfree(aggr); |
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return res; |
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} |
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static DRIVER_ATTR_WO(new_device); |
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static void gpio_aggregator_free(struct gpio_aggregator *aggr) |
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{ |
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platform_device_unregister(aggr->pdev); |
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gpiod_remove_lookup_table(aggr->lookups); |
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kfree(aggr->lookups->dev_id); |
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kfree(aggr->lookups); |
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kfree(aggr); |
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} |
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static ssize_t delete_device_store(struct device_driver *driver, |
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const char *buf, size_t count) |
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{ |
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struct gpio_aggregator *aggr; |
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unsigned int id; |
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int error; |
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if (!str_has_prefix(buf, DRV_NAME ".")) |
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return -EINVAL; |
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error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id); |
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if (error) |
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return error; |
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mutex_lock(&gpio_aggregator_lock); |
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aggr = idr_remove(&gpio_aggregator_idr, id); |
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mutex_unlock(&gpio_aggregator_lock); |
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if (!aggr) |
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return -ENOENT; |
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gpio_aggregator_free(aggr); |
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return count; |
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} |
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static DRIVER_ATTR_WO(delete_device); |
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static struct attribute *gpio_aggregator_attrs[] = { |
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&driver_attr_new_device.attr, |
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&driver_attr_delete_device.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(gpio_aggregator); |
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static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data) |
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{ |
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gpio_aggregator_free(p); |
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return 0; |
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} |
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static void __exit gpio_aggregator_remove_all(void) |
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{ |
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mutex_lock(&gpio_aggregator_lock); |
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idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL); |
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idr_destroy(&gpio_aggregator_idr); |
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mutex_unlock(&gpio_aggregator_lock); |
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} |
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/* |
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* GPIO Forwarder |
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*/ |
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struct gpiochip_fwd { |
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struct gpio_chip chip; |
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struct gpio_desc **descs; |
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union { |
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struct mutex mlock; /* protects tmp[] if can_sleep */ |
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spinlock_t slock; /* protects tmp[] if !can_sleep */ |
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}; |
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unsigned long tmp[]; /* values and descs for multiple ops */ |
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}; |
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static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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return gpiod_get_direction(fwd->descs[offset]); |
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} |
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static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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return gpiod_direction_input(fwd->descs[offset]); |
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} |
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static int gpio_fwd_direction_output(struct gpio_chip *chip, |
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unsigned int offset, int value) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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return gpiod_direction_output(fwd->descs[offset], value); |
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} |
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static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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return gpiod_get_value(fwd->descs[offset]); |
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} |
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static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask, |
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unsigned long *bits) |
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{ |
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struct gpio_desc **descs; |
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unsigned long *values; |
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unsigned int i, j = 0; |
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int error; |
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/* Both values bitmap and desc pointers are stored in tmp[] */ |
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values = &fwd->tmp[0]; |
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descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)]; |
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bitmap_clear(values, 0, fwd->chip.ngpio); |
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for_each_set_bit(i, mask, fwd->chip.ngpio) |
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descs[j++] = fwd->descs[i]; |
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error = gpiod_get_array_value(j, descs, NULL, values); |
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if (error) |
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return error; |
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j = 0; |
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for_each_set_bit(i, mask, fwd->chip.ngpio) |
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__assign_bit(i, bits, test_bit(j++, values)); |
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return 0; |
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} |
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static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip, |
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unsigned long *mask, unsigned long *bits) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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unsigned long flags; |
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int error; |
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if (chip->can_sleep) { |
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mutex_lock(&fwd->mlock); |
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error = gpio_fwd_get_multiple(fwd, mask, bits); |
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mutex_unlock(&fwd->mlock); |
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} else { |
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spin_lock_irqsave(&fwd->slock, flags); |
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error = gpio_fwd_get_multiple(fwd, mask, bits); |
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spin_unlock_irqrestore(&fwd->slock, flags); |
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} |
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return error; |
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} |
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static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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gpiod_set_value(fwd->descs[offset], value); |
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} |
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static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask, |
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unsigned long *bits) |
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{ |
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struct gpio_desc **descs; |
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unsigned long *values; |
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unsigned int i, j = 0; |
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/* Both values bitmap and desc pointers are stored in tmp[] */ |
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values = &fwd->tmp[0]; |
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descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)]; |
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for_each_set_bit(i, mask, fwd->chip.ngpio) { |
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__assign_bit(j, values, test_bit(i, bits)); |
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descs[j++] = fwd->descs[i]; |
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} |
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gpiod_set_array_value(j, descs, NULL, values); |
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} |
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static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip, |
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unsigned long *mask, unsigned long *bits) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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unsigned long flags; |
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if (chip->can_sleep) { |
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mutex_lock(&fwd->mlock); |
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gpio_fwd_set_multiple(fwd, mask, bits); |
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mutex_unlock(&fwd->mlock); |
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} else { |
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spin_lock_irqsave(&fwd->slock, flags); |
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gpio_fwd_set_multiple(fwd, mask, bits); |
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spin_unlock_irqrestore(&fwd->slock, flags); |
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} |
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} |
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static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset, |
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unsigned long config) |
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{ |
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struct gpiochip_fwd *fwd = gpiochip_get_data(chip); |
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return gpiod_set_config(fwd->descs[offset], config); |
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} |
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/** |
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* gpiochip_fwd_create() - Create a new GPIO forwarder |
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* @dev: Parent device pointer |
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* @ngpios: Number of GPIOs in the forwarder. |
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* @descs: Array containing the GPIO descriptors to forward to. |
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* This array must contain @ngpios entries, and must not be deallocated |
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* before the forwarder has been destroyed again. |
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* |
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* This function creates a new gpiochip, which forwards all GPIO operations to |
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* the passed GPIO descriptors. |
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* |
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* Return: An opaque object pointer, or an ERR_PTR()-encoded negative error |
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* code on failure. |
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*/ |
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static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev, |
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unsigned int ngpios, |
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struct gpio_desc *descs[]) |
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{ |
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const char *label = dev_name(dev); |
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struct gpiochip_fwd *fwd; |
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struct gpio_chip *chip; |
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unsigned int i; |
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int error; |
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fwd = devm_kzalloc(dev, struct_size(fwd, tmp, |
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BITS_TO_LONGS(ngpios) + ngpios), GFP_KERNEL); |
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if (!fwd) |
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return ERR_PTR(-ENOMEM); |
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chip = &fwd->chip; |
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/* |
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* If any of the GPIO lines are sleeping, then the entire forwarder |
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* will be sleeping. |
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* If any of the chips support .set_config(), then the forwarder will |
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* support setting configs. |
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*/ |
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for (i = 0; i < ngpios; i++) { |
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struct gpio_chip *parent = gpiod_to_chip(descs[i]); |
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dev_dbg(dev, "%u => gpio-%d\n", i, desc_to_gpio(descs[i])); |
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if (gpiod_cansleep(descs[i])) |
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chip->can_sleep = true; |
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if (parent && parent->set_config) |
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chip->set_config = gpio_fwd_set_config; |
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} |
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chip->label = label; |
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chip->parent = dev; |
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chip->owner = THIS_MODULE; |
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chip->get_direction = gpio_fwd_get_direction; |
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chip->direction_input = gpio_fwd_direction_input; |
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chip->direction_output = gpio_fwd_direction_output; |
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chip->get = gpio_fwd_get; |
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chip->get_multiple = gpio_fwd_get_multiple_locked; |
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chip->set = gpio_fwd_set; |
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chip->set_multiple = gpio_fwd_set_multiple_locked; |
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chip->base = -1; |
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chip->ngpio = ngpios; |
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fwd->descs = descs; |
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if (chip->can_sleep) |
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mutex_init(&fwd->mlock); |
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else |
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spin_lock_init(&fwd->slock); |
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error = devm_gpiochip_add_data(dev, chip, fwd); |
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if (error) |
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return ERR_PTR(error); |
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return fwd; |
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} |
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/* |
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* GPIO Aggregator platform device |
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*/ |
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static int gpio_aggregator_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct gpio_desc **descs; |
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struct gpiochip_fwd *fwd; |
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int i, n; |
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n = gpiod_count(dev, NULL); |
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if (n < 0) |
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return n; |
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descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL); |
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if (!descs) |
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return -ENOMEM; |
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for (i = 0; i < n; i++) { |
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descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); |
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if (IS_ERR(descs[i])) |
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return PTR_ERR(descs[i]); |
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} |
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fwd = gpiochip_fwd_create(dev, n, descs); |
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if (IS_ERR(fwd)) |
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return PTR_ERR(fwd); |
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platform_set_drvdata(pdev, fwd); |
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return 0; |
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} |
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#ifdef CONFIG_OF |
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static const struct of_device_id gpio_aggregator_dt_ids[] = { |
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/* |
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* Add GPIO-operated devices controlled from userspace below, |
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* or use "driver_override" in sysfs |
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*/ |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids); |
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#endif |
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static struct platform_driver gpio_aggregator_driver = { |
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.probe = gpio_aggregator_probe, |
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.driver = { |
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.name = DRV_NAME, |
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.groups = gpio_aggregator_groups, |
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.of_match_table = of_match_ptr(gpio_aggregator_dt_ids), |
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}, |
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}; |
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static int __init gpio_aggregator_init(void) |
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{ |
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return platform_driver_register(&gpio_aggregator_driver); |
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} |
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module_init(gpio_aggregator_init); |
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static void __exit gpio_aggregator_exit(void) |
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{ |
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gpio_aggregator_remove_all(); |
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platform_driver_unregister(&gpio_aggregator_driver); |
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} |
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module_exit(gpio_aggregator_exit); |
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MODULE_AUTHOR("Geert Uytterhoeven <[email protected]>"); |
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MODULE_DESCRIPTION("GPIO Aggregator"); |
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MODULE_LICENSE("GPL v2");
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