537 lines
13 KiB
C
537 lines
13 KiB
C
// 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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#define fwd_tmp_values(fwd) &(fwd)->tmp[0]
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#define fwd_tmp_descs(fwd) (void *)&(fwd)->tmp[BITS_TO_LONGS((fwd)->chip.ngpio)]
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#define fwd_tmp_size(ngpios) (BITS_TO_LONGS((ngpios)) + (ngpios))
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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 chip->can_sleep ? gpiod_get_value_cansleep(fwd->descs[offset])
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: 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 = fwd_tmp_descs(fwd);
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unsigned long *values = fwd_tmp_values(fwd);
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unsigned int i, j = 0;
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int error;
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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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if (fwd->chip.can_sleep)
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error = gpiod_get_array_value_cansleep(j, descs, NULL, values);
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else
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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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if (chip->can_sleep)
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gpiod_set_value_cansleep(fwd->descs[offset], value);
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else
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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 = fwd_tmp_descs(fwd);
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unsigned long *values = fwd_tmp_values(fwd);
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unsigned int i, j = 0;
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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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if (fwd->chip.can_sleep)
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gpiod_set_array_value_cansleep(j, descs, NULL, values);
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else
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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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static int gpio_fwd_to_irq(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_to_irq(fwd->descs[offset]);
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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, fwd_tmp_size(ngpios)),
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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 irq %d\n", i,
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desc_to_gpio(descs[i]), gpiod_to_irq(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->to_irq = gpio_fwd_to_irq;
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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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{
|
|
return platform_driver_register(&gpio_aggregator_driver);
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|
}
|
|
module_init(gpio_aggregator_init);
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|
|
|
static void __exit gpio_aggregator_exit(void)
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|
{
|
|
gpio_aggregator_remove_all();
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|
platform_driver_unregister(&gpio_aggregator_driver);
|
|
}
|
|
module_exit(gpio_aggregator_exit);
|
|
|
|
MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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|
MODULE_DESCRIPTION("GPIO Aggregator");
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|
MODULE_LICENSE("GPL v2");
|