diff options
| -rw-r--r-- | Documentation/admin-guide/gpio/gpio-virtuser.rst | 177 | ||||
| -rw-r--r-- | Documentation/admin-guide/gpio/index.rst | 1 | ||||
| -rw-r--r-- | drivers/gpio/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/gpio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/gpio/gpio-virtuser.c | 1807 |
5 files changed, 1998 insertions, 0 deletions
diff --git a/Documentation/admin-guide/gpio/gpio-virtuser.rst b/Documentation/admin-guide/gpio/gpio-virtuser.rst new file mode 100644 index 000000000000..2aca70db9f3b --- /dev/null +++ b/Documentation/admin-guide/gpio/gpio-virtuser.rst @@ -0,0 +1,177 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +Virtual GPIO Consumer +===================== + +The virtual GPIO Consumer module allows users to instantiate virtual devices +that request GPIOs and then control their behavior over debugfs. Virtual +consumer devices can be instantiated from device-tree or over configfs. + +A virtual consumer uses the driver-facing GPIO APIs and allows to cover it with +automated tests driven by user-space. The GPIOs are requested using +``gpiod_get_array()`` and so we support multiple GPIOs per connector ID. + +Creating GPIO consumers +----------------------- + +The gpio-consumer module registers a configfs subsystem called +``'gpio-virtuser'``. For details of the configfs filesystem, please refer to +the configfs documentation. + +The user can create a hierarchy of configfs groups and items as well as modify +values of exposed attributes. Once the consumer is instantiated, this hierarchy +will be translated to appropriate device properties. The general structure is: + +**Group:** ``/config/gpio-virtuser`` + +This is the top directory of the gpio-consumer configfs tree. + +**Group:** ``/config/gpio-consumer/example-name`` + +**Attribute:** ``/config/gpio-consumer/example-name/live`` + +**Attribute:** ``/config/gpio-consumer/example-name/dev_name`` + +This is a directory representing a GPIO consumer device. + +The read-only ``dev_name`` attribute exposes the name of the device as it will +appear in the system on the platform bus. This is useful for locating the +associated debugfs directory under +``/sys/kernel/debug/gpio-virtuser/$dev_name``. + +The ``'live'`` attribute allows to trigger the actual creation of the device +once it's fully configured. The accepted values are: ``'1'`` to enable the +virtual device and ``'0'`` to disable and tear it down. + +Creating GPIO lookup tables +--------------------------- + +Users can create a number of configfs groups under the device group: + +**Group:** ``/config/gpio-consumer/example-name/con_id`` + +The ``'con_id'`` directory represents a single GPIO lookup and its value maps +to the ``'con_id'`` argument of the ``gpiod_get()`` function. For example: +``con_id`` == ``'reset'`` maps to the ``reset-gpios`` device property. + +Users can assign a number of GPIOs to each lookup. Each GPIO is a sub-directory +with a user-defined name under the ``'con_id'`` group. + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/key`` + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/offset`` + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/drive`` + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/pull`` + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/active_low`` + +**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/transitory`` + +This is a group describing a single GPIO in the ``con_id-gpios`` property. + +For virtual consumers created using configfs we use machine lookup tables so +this group can be considered as a mapping between the filesystem and the fields +of a single entry in ``'struct gpiod_lookup'``. + +The ``'key'`` attribute represents either the name of the chip this GPIO +belongs to or the GPIO line name. This depends on the value of the ``'offset'`` +attribute: if its value is >= 0, then ``'key'`` represents the label of the +chip to lookup while ``'offset'`` represents the offset of the line in that +chip. If ``'offset'`` is < 0, then ``'key'`` represents the name of the line. + +The remaining attributes map to the ``'flags'`` field of the GPIO lookup +struct. The first two take string values as arguments: + +**``'drive'``:** ``'push-pull'``, ``'open-drain'``, ``'open-source'`` +**``'pull'``:** ``'pull-up'``, ``'pull-down'``, ``'pull-disabled'``, ``'as-is'`` + +``'active_low'`` and ``'transitory'`` are boolean attributes. + +Activating GPIO consumers +------------------------- + +Once the confiuration is complete, the ``'live'`` attribute must be set to 1 in +order to instantiate the consumer. It can be set back to 0 to destroy the +virtual device. The module will synchronously wait for the new simulated device +to be successfully probed and if this doesn't happen, writing to ``'live'`` will +result in an error. + +Device-tree +----------- + +Virtual GPIO consumers can also be defined in device-tree. The compatible string +must be: ``"gpio-virtuser"`` with at least one property following the +standardized GPIO pattern. + +An example device-tree code defining a virtual GPIO consumer: + +.. code-block :: none + + gpio-virt-consumer { + compatible = "gpio-virtuser"; + + foo-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>, <&gpio1 2 0>; + bar-gpios = <&gpio0 6 0>; + }; + +Controlling virtual GPIO consumers +---------------------------------- + +Once active, the device will export debugfs attributes for controlling GPIO +arrays as well as each requested GPIO line separately. Let's consider the +following device property: ``foo-gpios = <&gpio0 0 0>, <&gpio0 4 0>;``. + +The following debugfs attribute groups will be created: + +**Group:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/`` + +This is the group that will contain the attributes for the entire GPIO array. + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/values`` + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/values_atomic`` + +Both attributes allow to read and set arrays of GPIO values. User must pass +exactly the number of values that the array contains in the form of a string +containing zeroes and ones representing inactive and active GPIO states +respectively. In this example: ``echo 11 > values``. + +The ``values_atomic`` attribute works the same as ``values`` but the kernel +will execute the GPIO driver callbacks in interrupt context. + +**Group:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/`` + +This is a group that represents a single GPIO with ``$index`` being its offset +in the array. + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/consumer`` + +Allows to set and read the consumer label of the GPIO line. + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/debounce`` + +Allows to set and read the debounce period of the GPIO line. + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/direction`` + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/direction_atomic`` + +These two attributes allow to set the direction of the GPIO line. They accept +"input" and "output" as values. The atomic variant executes the driver callback +in interrupt context. + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/interrupts`` + +If the line is requested in input mode, writing ``1`` to this attribute will +make the module listen for edge interrupts on the GPIO. Writing ``0`` disables +the monitoring. Reading this attribute returns the current number of registered +interrupts (both edges). + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/value`` + +**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/value_atomic`` + +Both attributes allow to read and set values of individual requested GPIO lines. +They accept the following values: ``1`` and ``0``. diff --git a/Documentation/admin-guide/gpio/index.rst b/Documentation/admin-guide/gpio/index.rst index 460afd29617e..712f379731cb 100644 --- a/Documentation/admin-guide/gpio/index.rst +++ b/Documentation/admin-guide/gpio/index.rst @@ -10,6 +10,7 @@ GPIO Character Device Userspace API <../../userspace-api/gpio/chardev> gpio-aggregator gpio-sim + gpio-virtuser Obsolete APIs <obsolete> .. only:: subproject and html diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 2b9bd1893863..ba93e640a8ab 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1908,6 +1908,18 @@ config GPIO_SLOPPY_LOGIC_ANALYZER If this driver is built as a module it will be called 'gpio-sloppy-logic-analyzer'. +config GPIO_VIRTUSER + tristate "GPIO Virtual User Testing Module" + select DEBUG_FS + select CONFIGFS_FS + select IRQ_WORK + help + Say Y here to enable the configurable, configfs-based virtual GPIO + consumer testing driver. + + This driver is aimed as a helper in spotting any regressions in + hot-unplug handling in GPIOLIB. + endmenu endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 9889f5b962bf..64dd6d9d730d 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -182,6 +182,7 @@ obj-$(CONFIG_GPIO_TWL6040) += gpio-twl6040.o obj-$(CONFIG_GPIO_UNIPHIER) += gpio-uniphier.o obj-$(CONFIG_GPIO_VF610) += gpio-vf610.o obj-$(CONFIG_GPIO_VIPERBOARD) += gpio-viperboard.o +obj-$(CONFIG_GPIO_VIRTUSER) += gpio-virtuser.o obj-$(CONFIG_GPIO_VIRTIO) += gpio-virtio.o obj-$(CONFIG_GPIO_VISCONTI) += gpio-visconti.o obj-$(CONFIG_GPIO_VX855) += gpio-vx855.o diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c new file mode 100644 index 000000000000..2ac09c6a3763 --- /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(buf, "input") == 0) { + dir = 1; + } else if (strcmp(buf, "output-high") == 0) { + dir = 0; + val = 1; + } else if (strcmp(buf, "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); |