diff options
Diffstat (limited to 'drivers/gpio/gpio-virtuser.c')
| -rw-r--r-- | drivers/gpio/gpio-virtuser.c | 1807 |
1 files changed, 1807 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c new file mode 100644 index 000000000000..0e0d55da4f01 --- /dev/null +++ b/drivers/gpio/gpio-virtuser.c @@ -0,0 +1,1807 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Configurable virtual GPIO consumer module. + * + * Copyright (C) 2023-2024 Bartosz Golaszewski <bartosz.golaszewski@linaro.org> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/array_size.h> +#include <linux/atomic.h> +#include <linux/bitmap.h> +#include <linux/cleanup.h> +#include <linux/completion.h> +#include <linux/configfs.h> +#include <linux/debugfs.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/gpio/machine.h> +#include <linux/idr.h> +#include <linux/interrupt.h> +#include <linux/irq_work.h> +#include <linux/limits.h> +#include <linux/list.h> +#include <linux/lockdep.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/notifier.h> +#include <linux/of.h> +#include <linux/overflow.h> +#include <linux/platform_device.h> +#include <linux/printk.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/string_helpers.h> +#include <linux/types.h> + +#define GPIO_VIRTUSER_NAME_BUF_LEN 32 + +static DEFINE_IDA(gpio_virtuser_ida); +static struct dentry *gpio_virtuser_dbg_root; + +struct gpio_virtuser_attr_data { + union { + struct gpio_desc *desc; + struct gpio_descs *descs; + }; + struct dentry *dbgfs_dir; +}; + +struct gpio_virtuser_line_array_data { + struct gpio_virtuser_attr_data ad; +}; + +struct gpio_virtuser_line_data { + struct gpio_virtuser_attr_data ad; + char consumer[GPIO_VIRTUSER_NAME_BUF_LEN]; + struct mutex consumer_lock; + unsigned int debounce; + atomic_t irq; + atomic_t irq_count; +}; + +struct gpio_virtuser_dbgfs_attr_descr { + const char *name; + const struct file_operations *fops; +}; + +struct gpio_virtuser_irq_work_context { + struct irq_work work; + struct completion work_completion; + union { + struct { + struct gpio_desc *desc; + int dir; + int val; + int ret; + }; + struct { + struct gpio_descs *descs; + unsigned long *values; + }; + }; +}; + +static struct gpio_virtuser_irq_work_context * +to_gpio_virtuser_irq_work_context(struct irq_work *work) +{ + return container_of(work, struct gpio_virtuser_irq_work_context, work); +} + +static void +gpio_virtuser_init_irq_work_context(struct gpio_virtuser_irq_work_context *ctx) +{ + memset(ctx, 0, sizeof(*ctx)); + init_completion(&ctx->work_completion); +} + +static void +gpio_virtuser_irq_work_queue_sync(struct gpio_virtuser_irq_work_context *ctx) +{ + irq_work_queue(&ctx->work); + wait_for_completion(&ctx->work_completion); +} + +static void gpio_virtuser_dbgfs_emit_value_array(char *buf, + unsigned long *values, + size_t num_values) +{ + size_t i; + + for (i = 0; i < num_values; i++) + buf[i] = test_bit(i, values) ? '1' : '0'; + + buf[i++] = '\n'; +} + +static void gpio_virtuser_get_value_array_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + struct gpio_descs *descs = ctx->descs; + + ctx->ret = gpiod_get_array_value(descs->ndescs, descs->desc, + descs->info, ctx->values); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_get_array_value(struct gpio_descs *descs, + unsigned long *values, bool atomic) +{ + struct gpio_virtuser_irq_work_context ctx; + + if (!atomic) + return gpiod_get_array_value_cansleep(descs->ndescs, + descs->desc, + descs->info, values); + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_get_value_array_atomic); + ctx.descs = descs; + ctx.values = values; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + return ctx.ret; +} + +static ssize_t gpio_virtuser_value_array_do_read(struct file *file, + char __user *user_buf, + size_t size, loff_t *ppos, + bool atomic) +{ + struct gpio_virtuser_line_data *data = file->private_data; + struct gpio_descs *descs = data->ad.descs; + size_t bufsize; + int ret; + + unsigned long *values __free(bitmap) = bitmap_zalloc(descs->ndescs, + GFP_KERNEL); + if (!values) + return -ENOMEM; + + ret = gpio_virtuser_get_array_value(descs, values, atomic); + if (ret) + return ret; + + bufsize = descs->ndescs + 2; + + char *buf __free(kfree) = kzalloc(bufsize, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + gpio_virtuser_dbgfs_emit_value_array(buf, values, descs->ndescs); + + return simple_read_from_buffer(user_buf, size, ppos, buf, + descs->ndescs + 1); +} + +static int gpio_virtuser_dbgfs_parse_value_array(const char *buf, + size_t len, + unsigned long *values) +{ + size_t i; + + for (i = 0; i < len; i++) { + if (buf[i] == '0') + clear_bit(i, values); + else if (buf[i] == '1') + set_bit(i, values); + else + return -EINVAL; + } + + return 0; +} + +static void gpio_virtuser_set_value_array_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + struct gpio_descs *descs = ctx->descs; + + ctx->ret = gpiod_set_array_value(descs->ndescs, descs->desc, + descs->info, ctx->values); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_set_array_value(struct gpio_descs *descs, + unsigned long *values, bool atomic) +{ + struct gpio_virtuser_irq_work_context ctx; + + if (!atomic) + return gpiod_set_array_value_cansleep(descs->ndescs, + descs->desc, + descs->info, values); + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_set_value_array_atomic); + ctx.descs = descs; + ctx.values = values; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + return ctx.ret; +} + +static ssize_t gpio_virtuser_value_array_do_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos, + bool atomic) +{ + struct gpio_virtuser_line_data *data = file->private_data; + struct gpio_descs *descs = data->ad.descs; + int ret; + + if (count - 1 != descs->ndescs) + return -EINVAL; + + char *buf __free(kfree) = kzalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = simple_write_to_buffer(buf, count, ppos, user_buf, count); + if (ret < 0) + return ret; + + unsigned long *values __free(bitmap) = bitmap_zalloc(descs->ndescs, + GFP_KERNEL); + if (!values) + return -ENOMEM; + + ret = gpio_virtuser_dbgfs_parse_value_array(buf, count - 1, values); + if (ret) + return ret; + + ret = gpio_virtuser_set_array_value(descs, values, atomic); + if (ret) + return ret; + + return count; +} + +static ssize_t gpio_virtuser_value_array_read(struct file *file, + char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_value_array_do_read(file, user_buf, count, ppos, + false); +} + +static ssize_t gpio_virtuser_value_array_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_value_array_do_write(file, user_buf, count, ppos, + false); +} + +static const struct file_operations gpio_virtuser_value_array_fops = { + .read = gpio_virtuser_value_array_read, + .write = gpio_virtuser_value_array_write, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static ssize_t +gpio_virtuser_value_array_atomic_read(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_value_array_do_read(file, user_buf, count, ppos, + true); +} + +static ssize_t +gpio_virtuser_value_array_atomic_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_value_array_do_write(file, user_buf, count, ppos, + true); +} + +static const struct file_operations gpio_virtuser_value_array_atomic_fops = { + .read = gpio_virtuser_value_array_atomic_read, + .write = gpio_virtuser_value_array_atomic_write, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static void gpio_virtuser_do_get_direction_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + + ctx->ret = gpiod_get_direction(ctx->desc); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_get_direction_atomic(struct gpio_desc *desc) +{ + struct gpio_virtuser_irq_work_context ctx; + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_do_get_direction_atomic); + ctx.desc = desc; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + return ctx.ret; +} + +static ssize_t gpio_virtuser_direction_do_read(struct file *file, + char __user *user_buf, + size_t size, loff_t *ppos, + bool atomic) +{ + struct gpio_virtuser_line_data *data = file->private_data; + struct gpio_desc *desc = data->ad.desc; + char buf[32]; + int dir; + + if (!atomic) + dir = gpiod_get_direction(desc); + else + dir = gpio_virtuser_get_direction_atomic(desc); + if (dir < 0) + return dir; + + snprintf(buf, sizeof(buf), "%s\n", dir ? "input" : "output"); + + return simple_read_from_buffer(user_buf, size, ppos, buf, strlen(buf)); +} + +static int gpio_virtuser_set_direction(struct gpio_desc *desc, int dir, int val) +{ + if (dir) + return gpiod_direction_input(desc); + + return gpiod_direction_output(desc, val); +} + +static void gpio_virtuser_do_set_direction_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + + ctx->ret = gpio_virtuser_set_direction(ctx->desc, ctx->dir, ctx->val); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_set_direction_atomic(struct gpio_desc *desc, + int dir, int val) +{ + struct gpio_virtuser_irq_work_context ctx; + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_do_set_direction_atomic); + ctx.desc = desc; + ctx.dir = dir; + ctx.val = val; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + return ctx.ret; +} + +static ssize_t gpio_virtuser_direction_do_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos, + bool atomic) +{ + struct gpio_virtuser_line_data *data = file->private_data; + struct gpio_desc *desc = data->ad.desc; + char buf[32], *trimmed; + int ret, dir, val = 0; + + ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count); + if (ret < 0) + return ret; + + trimmed = strim(buf); + + if (strcmp(trimmed, "input") == 0) { + dir = 1; + } else if (strcmp(trimmed, "output-high") == 0) { + dir = 0; + val = 1; + } else if (strcmp(trimmed, "output-low") == 0) { + dir = val = 0; + } else { + return -EINVAL; + } + + if (!atomic) + ret = gpio_virtuser_set_direction(desc, dir, val); + else + ret = gpio_virtuser_set_direction_atomic(desc, dir, val); + if (ret) + return ret; + + return count; +} + +static ssize_t gpio_virtuser_direction_read(struct file *file, + char __user *user_buf, + size_t size, loff_t *ppos) +{ + return gpio_virtuser_direction_do_read(file, user_buf, size, ppos, + false); +} + +static ssize_t gpio_virtuser_direction_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_direction_do_write(file, user_buf, count, ppos, + false); +} + +static const struct file_operations gpio_virtuser_direction_fops = { + .read = gpio_virtuser_direction_read, + .write = gpio_virtuser_direction_write, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static ssize_t gpio_virtuser_direction_atomic_read(struct file *file, + char __user *user_buf, + size_t size, loff_t *ppos) +{ + return gpio_virtuser_direction_do_read(file, user_buf, size, ppos, + true); +} + +static ssize_t gpio_virtuser_direction_atomic_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + return gpio_virtuser_direction_do_write(file, user_buf, count, ppos, + true); +} + +static const struct file_operations gpio_virtuser_direction_atomic_fops = { + .read = gpio_virtuser_direction_atomic_read, + .write = gpio_virtuser_direction_atomic_write, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static int gpio_virtuser_value_get(void *data, u64 *val) +{ + struct gpio_virtuser_line_data *ld = data; + int ret; + + ret = gpiod_get_value_cansleep(ld->ad.desc); + if (ret < 0) + return ret; + + *val = ret; + + return 0; +} + +static int gpio_virtuser_value_set(void *data, u64 val) +{ + struct gpio_virtuser_line_data *ld = data; + + if (val > 1) + return -EINVAL; + + gpiod_set_value_cansleep(ld->ad.desc, (int)val); + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_fops, + gpio_virtuser_value_get, + gpio_virtuser_value_set, + "%llu\n"); + +static void gpio_virtuser_get_value_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + + ctx->val = gpiod_get_value(ctx->desc); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_value_atomic_get(void *data, u64 *val) +{ + struct gpio_virtuser_line_data *ld = data; + struct gpio_virtuser_irq_work_context ctx; + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_get_value_atomic); + ctx.desc = ld->ad.desc; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + if (ctx.val < 0) + return ctx.val; + + *val = ctx.val; + + return 0; +} + +static void gpio_virtuser_set_value_atomic(struct irq_work *work) +{ + struct gpio_virtuser_irq_work_context *ctx = + to_gpio_virtuser_irq_work_context(work); + + gpiod_set_value(ctx->desc, ctx->val); + complete(&ctx->work_completion); +} + +static int gpio_virtuser_value_atomic_set(void *data, u64 val) +{ + struct gpio_virtuser_line_data *ld = data; + struct gpio_virtuser_irq_work_context ctx; + + if (val > 1) + return -EINVAL; + + gpio_virtuser_init_irq_work_context(&ctx); + ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_set_value_atomic); + ctx.desc = ld->ad.desc; + ctx.val = (int)val; + + gpio_virtuser_irq_work_queue_sync(&ctx); + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_atomic_fops, + gpio_virtuser_value_atomic_get, + gpio_virtuser_value_atomic_set, + "%llu\n"); + +static int gpio_virtuser_debounce_get(void *data, u64 *val) +{ + struct gpio_virtuser_line_data *ld = data; + + *val = READ_ONCE(ld->debounce); + + return 0; +} + +static int gpio_virtuser_debounce_set(void *data, u64 val) +{ + struct gpio_virtuser_line_data *ld = data; + int ret; + + if (val > UINT_MAX) + return -E2BIG; + + ret = gpiod_set_debounce(ld->ad.desc, (unsigned int)val); + if (ret) + /* Don't propagate errno unknown to user-space. */ + return ret == -ENOTSUPP ? -EOPNOTSUPP : ret; + + WRITE_ONCE(ld->debounce, (unsigned int)val); + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_debounce_fops, + gpio_virtuser_debounce_get, + gpio_virtuser_debounce_set, + "%llu\n"); + +static ssize_t gpio_virtuser_consumer_read(struct file *file, + char __user *user_buf, + size_t size, loff_t *ppos) +{ + struct gpio_virtuser_line_data *data = file->private_data; + char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 1]; + ssize_t ret; + + memset(buf, 0x0, sizeof(buf)); + + scoped_guard(mutex, &data->consumer_lock) + ret = snprintf(buf, sizeof(buf), "%s\n", data->consumer); + + return simple_read_from_buffer(user_buf, size, ppos, buf, ret); +} + +static ssize_t gpio_virtuser_consumer_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct gpio_virtuser_line_data *data = file->private_data; + char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 2]; + int ret; + + ret = simple_write_to_buffer(buf, GPIO_VIRTUSER_NAME_BUF_LEN, ppos, + user_buf, count); + if (ret < 0) + return ret; + + buf[strlen(buf) - 1] = '\0'; + + ret = gpiod_set_consumer_name(data->ad.desc, buf); + if (ret) + return ret; + + scoped_guard(mutex, &data->consumer_lock) + strscpy(data->consumer, buf, sizeof(data->consumer)); + + return count; +} + +static const struct file_operations gpio_virtuser_consumer_fops = { + .read = gpio_virtuser_consumer_read, + .write = gpio_virtuser_consumer_write, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static int gpio_virtuser_interrupts_get(void *data, u64 *val) +{ + struct gpio_virtuser_line_data *ld = data; + + *val = atomic_read(&ld->irq_count); + + return 0; +} + +static irqreturn_t gpio_virtuser_irq_handler(int irq, void *data) +{ + struct gpio_virtuser_line_data *ld = data; + + atomic_inc(&ld->irq_count); + + return IRQ_HANDLED; +} + +static int gpio_virtuser_interrupts_set(void *data, u64 val) +{ + struct gpio_virtuser_line_data *ld = data; + int irq, ret; + + if (val > 1) + return -EINVAL; + + if (val) { + irq = gpiod_to_irq(ld->ad.desc); + if (irq < 0) + return irq; + + ret = request_threaded_irq(irq, NULL, + gpio_virtuser_irq_handler, + IRQF_TRIGGER_RISING | + IRQF_TRIGGER_FALLING | + IRQF_ONESHOT, + ld->consumer, data); + if (ret) + return ret; + + atomic_set(&ld->irq, irq); + } else { + irq = atomic_xchg(&ld->irq, 0); + free_irq(irq, ld); + } + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_interrupts_fops, + gpio_virtuser_interrupts_get, + gpio_virtuser_interrupts_set, + "%llu\n"); + +static const struct gpio_virtuser_dbgfs_attr_descr +gpio_virtuser_line_array_dbgfs_attrs[] = { + { + .name = "values", + .fops = &gpio_virtuser_value_array_fops, + }, + { + .name = "values_atomic", + .fops = &gpio_virtuser_value_array_atomic_fops, + }, +}; + +static const struct gpio_virtuser_dbgfs_attr_descr +gpio_virtuser_line_dbgfs_attrs[] = { + { + .name = "direction", + .fops = &gpio_virtuser_direction_fops, + }, + { + .name = "direction_atomic", + .fops = &gpio_virtuser_direction_atomic_fops, + }, + { + .name = "value", + .fops = &gpio_virtuser_value_fops, + }, + { + .name = "value_atomic", + .fops = &gpio_virtuser_value_atomic_fops, + }, + { + .name = "debounce", + .fops = &gpio_virtuser_debounce_fops, + }, + { + .name = "consumer", + .fops = &gpio_virtuser_consumer_fops, + }, + { + .name = "interrupts", + .fops = &gpio_virtuser_interrupts_fops, + }, +}; + +static int gpio_virtuser_create_debugfs_attrs( + const struct gpio_virtuser_dbgfs_attr_descr *attr, + size_t num_attrs, struct dentry *parent, void *data) +{ + struct dentry *ret; + size_t i; + + for (i = 0; i < num_attrs; i++, attr++) { + ret = debugfs_create_file(attr->name, 0644, parent, data, + attr->fops); + if (IS_ERR(ret)) + return PTR_ERR(ret); + } + + return 0; +} + +static int gpio_virtuser_dbgfs_init_line_array_attrs(struct device *dev, + struct gpio_descs *descs, + const char *id, + struct dentry *dbgfs_entry) +{ + struct gpio_virtuser_line_array_data *data; + char *name; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->ad.descs = descs; + + name = devm_kasprintf(dev, GFP_KERNEL, "gpiod:%s", id); + if (!name) + return -ENOMEM; + + data->ad.dbgfs_dir = debugfs_create_dir(name, dbgfs_entry); + if (IS_ERR(data->ad.dbgfs_dir)) + return PTR_ERR(data->ad.dbgfs_dir); + + return gpio_virtuser_create_debugfs_attrs( + gpio_virtuser_line_array_dbgfs_attrs, + ARRAY_SIZE(gpio_virtuser_line_array_dbgfs_attrs), + data->ad.dbgfs_dir, data); +} + +static int gpio_virtuser_dbgfs_init_line_attrs(struct device *dev, + struct gpio_desc *desc, + const char *id, + unsigned int index, + struct dentry *dbgfs_entry) +{ + struct gpio_virtuser_line_data *data; + char *name; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->ad.desc = desc; + sprintf(data->consumer, id); + atomic_set(&data->irq, 0); + atomic_set(&data->irq_count, 0); + + name = devm_kasprintf(dev, GFP_KERNEL, "gpiod:%s:%u", id, index); + if (!name) + return -ENOMEM; + + ret = devm_mutex_init(dev, &data->consumer_lock); + if (ret) + return ret; + + data->ad.dbgfs_dir = debugfs_create_dir(name, dbgfs_entry); + if (IS_ERR(data->ad.dbgfs_dir)) + return PTR_ERR(data->ad.dbgfs_dir); + + return gpio_virtuser_create_debugfs_attrs( + gpio_virtuser_line_dbgfs_attrs, + ARRAY_SIZE(gpio_virtuser_line_dbgfs_attrs), + data->ad.dbgfs_dir, data); +} + +static void gpio_virtuser_debugfs_remove(void *data) +{ + struct dentry *dbgfs_entry = data; + + debugfs_remove_recursive(dbgfs_entry); +} + +static int gpio_virtuser_prop_is_gpio(struct property *prop) +{ + char *dash = strrchr(prop->name, '-'); + + return dash && strcmp(dash, "-gpios") == 0; +} + +/* + * If this is an OF-based system, then we iterate over properties and consider + * all whose names end in "-gpios". For configfs we expect an additional string + * array property - "gpio-virtuser,ids" - containing the list of all GPIO IDs + * to request. + */ +static int gpio_virtuser_count_ids(struct device *dev) +{ + struct device_node *of_node = dev_of_node(dev); + struct property *prop; + int ret = 0; + + if (!of_node) + return device_property_string_array_count(dev, + "gpio-virtuser,ids"); + + for_each_property_of_node(of_node, prop) { + if (gpio_virtuser_prop_is_gpio(prop)) + ++ret; + } + + return ret; +} + +static int gpio_virtuser_get_ids(struct device *dev, const char **ids, + int num_ids) +{ + struct device_node *of_node = dev_of_node(dev); + struct property *prop; + size_t pos = 0, diff; + char *dash, *tmp; + + if (!of_node) + return device_property_read_string_array(dev, + "gpio-virtuser,ids", + ids, num_ids); + + for_each_property_of_node(of_node, prop) { + if (!gpio_virtuser_prop_is_gpio(prop)) + continue; + + dash = strrchr(prop->name, '-'); + diff = dash - prop->name; + + tmp = devm_kmemdup(dev, prop->name, diff + 1, + GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + tmp[diff] = '\0'; + ids[pos++] = tmp; + } + + return 0; +} + +static int gpio_virtuser_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dentry *dbgfs_entry; + struct gpio_descs *descs; + int ret, num_ids = 0, i; + const char **ids; + unsigned int j; + + num_ids = gpio_virtuser_count_ids(dev); + if (num_ids < 0) + return dev_err_probe(dev, num_ids, + "Failed to get the number of GPIOs to request\n"); + + if (num_ids == 0) + return dev_err_probe(dev, -EINVAL, "No GPIO IDs specified\n"); + + ids = devm_kcalloc(dev, num_ids, sizeof(*ids), GFP_KERNEL); + if (!ids) + return -ENOMEM; + + ret = gpio_virtuser_get_ids(dev, ids, num_ids); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to get the IDs of GPIOs to request\n"); + + dbgfs_entry = debugfs_create_dir(dev_name(dev), gpio_virtuser_dbg_root); + ret = devm_add_action_or_reset(dev, gpio_virtuser_debugfs_remove, + dbgfs_entry); + if (ret) + return ret; + + for (i = 0; i < num_ids; i++) { + descs = devm_gpiod_get_array(dev, ids[i], GPIOD_ASIS); + if (IS_ERR(descs)) + return dev_err_probe(dev, PTR_ERR(descs), + "Failed to request the '%s' GPIOs\n", + ids[i]); + + ret = gpio_virtuser_dbgfs_init_line_array_attrs(dev, descs, + ids[i], + dbgfs_entry); + if (ret) + return dev_err_probe(dev, ret, + "Failed to setup the debugfs array interface for the '%s' GPIOs\n", + ids[i]); + + for (j = 0; j < descs->ndescs; j++) { + ret = gpio_virtuser_dbgfs_init_line_attrs(dev, + descs->desc[j], ids[i], + j, dbgfs_entry); + if (ret) + return dev_err_probe(dev, ret, + "Failed to setup the debugfs line interface for the '%s' GPIOs\n", + ids[i]); + } + } + + return 0; +} + +static const struct of_device_id gpio_virtuser_of_match[] = { + { .compatible = "gpio-virtuser" }, + { } +}; +MODULE_DEVICE_TABLE(of, gpio_virtuser_of_match); + +static struct platform_driver gpio_virtuser_driver = { + .driver = { + .name = "gpio-virtuser", + .of_match_table = gpio_virtuser_of_match, + }, + .probe = gpio_virtuser_probe, +}; + +struct gpio_virtuser_device { + struct config_group group; + + struct platform_device *pdev; + int id; + struct mutex lock; + + struct notifier_block bus_notifier; + struct completion probe_completion; + bool driver_bound; + + struct gpiod_lookup_table *lookup_table; + + struct list_head lookup_list; +}; + +static int gpio_virtuser_bus_notifier_call(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct gpio_virtuser_device *vdev; + struct device *dev = data; + char devname[32]; + + vdev = container_of(nb, struct gpio_virtuser_device, bus_notifier); + snprintf(devname, sizeof(devname), "gpio-virtuser.%d", vdev->id); + + if (!device_match_name(dev, devname)) + return NOTIFY_DONE; + + switch (action) { + case BUS_NOTIFY_BOUND_DRIVER: + vdev->driver_bound = true; + break; + case BUS_NOTIFY_DRIVER_NOT_BOUND: + vdev->driver_bound = false; + break; + default: + return NOTIFY_DONE; + } + + complete(&vdev->probe_completion); + return NOTIFY_OK; +} + +static struct gpio_virtuser_device * +to_gpio_virtuser_device(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_virtuser_device, group); +} + +static bool +gpio_virtuser_device_is_live(struct gpio_virtuser_device *dev) +{ + lockdep_assert_held(&dev->lock); + + return !!dev->pdev; +} + +struct gpio_virtuser_lookup { + struct config_group group; + + struct gpio_virtuser_device *parent; + struct list_head siblings; + + char *con_id; + + struct list_head entry_list; +}; + +static struct gpio_virtuser_lookup * +to_gpio_virtuser_lookup(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_virtuser_lookup, group); +} + +struct gpio_virtuser_lookup_entry { + struct config_group group; + + struct gpio_virtuser_lookup *parent; + struct list_head siblings; + + char *key; + /* Can be negative to indicate lookup by name. */ + int offset; + enum gpio_lookup_flags flags; +}; + +static struct gpio_virtuser_lookup_entry * +to_gpio_virtuser_lookup_entry(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_virtuser_lookup_entry, group); +} + +static ssize_t +gpio_virtuser_lookup_entry_config_key_show(struct config_item *item, char *page) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + + guard(mutex)(&dev->lock); + + return sprintf(page, "%s\n", entry->key ?: ""); +} + +static ssize_t +gpio_virtuser_lookup_entry_config_key_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + + char *key __free(kfree) = kstrndup(skip_spaces(page), count, + GFP_KERNEL); + if (!key) + return -ENOMEM; + + strim(key); + + guard(mutex)(&dev->lock); + + if (gpio_virtuser_device_is_live(dev)) + return -EBUSY; + + kfree(entry->key); + entry->key = no_free_ptr(key); + + return count; +} + +CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, key); + +static ssize_t +gpio_virtuser_lookup_entry_config_offset_show(struct config_item *item, + char *page) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + unsigned int offset; + + scoped_guard(mutex, &dev->lock) + offset = entry->offset; + + return sprintf(page, "%d\n", offset); +} + +static ssize_t +gpio_virtuser_lookup_entry_config_offset_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + int offset, ret; + + ret = kstrtoint(page, 0, &offset); + if (ret) + return ret; + + /* + * Negative number here means: 'key' represents a line name to lookup. + * Non-negative means: 'key' represents the label of the chip with + * the 'offset' value representing the line within that chip. + * + * GPIOLIB uses the U16_MAX value to indicate lookup by line name so + * the greatest offset we can accept is (U16_MAX - 1). + */ + if (offset > (U16_MAX - 1)) + return -EINVAL; + + guard(mutex)(&dev->lock); + + if (gpio_virtuser_device_is_live(dev)) + return -EBUSY; + + entry->offset = offset; + + return count; +} + +CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, offset); + +static enum gpio_lookup_flags +gpio_virtuser_lookup_get_flags(struct config_item *item) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + + guard(mutex)(&dev->lock); + + return entry->flags; +} + +static ssize_t +gpio_virtuser_lookup_entry_config_drive_show(struct config_item *item, char *page) +{ + enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item); + const char *repr; + + if (flags & GPIO_OPEN_DRAIN) + repr = "open-drain"; + else if (flags & GPIO_OPEN_SOURCE) + repr = "open-source"; + else + repr = "push-pull"; + + return sprintf(page, "%s\n", repr); +} + +static ssize_t +gpio_virtuser_lookup_entry_config_drive_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_virtuser_lookup_entry *entry = + to_gpio_virtuser_lookup_entry(item); + struct gpio_virtuser_device *dev = entry->parent->parent; + + guard(mutex)(&dev->lock); + + if (gpio_virtuser_device_is_live(dev)) + return -EBUSY; + + if (sysfs_streq(page, "push-pull")) { + entry->flags &= ~(GPIO_OPEN_DRAIN | GPIO_OPEN_SOURCE); + } else if (sysfs_streq(page, "open-drain")) { + entry->flags &= ~GPIO_OPEN_SOURCE; + entry->flags |= GPIO_OPEN_DRAIN; + } else if (sysfs_streq(page, "open-source")) { + entry->flags &= ~GPIO_OPEN_DRAIN; + entry->flags |= GPIO_OPEN_SOURCE; + } else { + count = -EINVAL; + } + + return count; +} + +CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, drive); + +static ssize_t +gpio_virtuser_lookup_entry_config_pull_show(struct config_item *item, char *page) +{ + enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item); + const char *repr; + + if (flags & GPIO_PULL_UP) + repr = "pull-up"; + else if (flags & GPIO_PULL_DOWN) + repr = "pull-down"; + else if (flags & GPIO_PULL_DISABLE) + repr = "pull-disabled"; + else + repr = "as-is"; + + return sprintf(page, "%s\n", repr); +} + +static ssize_t +gpio_virtuser_lookup_entry_config_pull_store(struct config_item *item, + const char |