new file mode 100644
@@ -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:$index/value_atomic``
+
+Both attributes allow to read and set values of individual requested GPIO lines.
+They accept the following values: ``1`` and ``0``.
@@ -10,6 +10,7 @@ GPIO
Character Device Userspace API <../../userspace-api/gpio/chardev>
gpio-aggregator
gpio-sim
+ gpio-virtuser
Obsolete APIs <obsolete>
.. only:: subproject and html
@@ -1891,4 +1891,20 @@ config GPIO_SIM
endmenu
+menu "GPIO Debugging utilities"
+
+config GPIO_VIRTUSER
+ tristate "GPIO Virtual User Testing Module"
+ select DEBUG_FS
+ select CONFIGFS_FS
+ select IRQ_WORK
+ help
+ Say Y here to enable the configurable, configfs-based virtual GPIO
+ consumer testing driver.
+
+ This driver is aimed as a helper in spotting any regressions in
+ hot-unplug handling in GPIOLIB.
+
+endmenu
+
endif
@@ -181,6 +181,7 @@ obj-$(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
new file mode 100644
@@ -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(buf));
+
+ 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 *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, "pull-up")) {
+ entry->flags &= ~(GPIO_PULL_DOWN | GPIO_PULL_DISABLE);
+ entry->flags |= GPIO_PULL_UP;
+ } else if (sysfs_streq(page, "pull-down")) {
+ entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DISABLE);
+ entry->flags |= GPIO_PULL_DOWN;
+ } else if (sysfs_streq(page, "pull-disabled")) {
+ entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN);
+ entry->flags |= GPIO_PULL_DISABLE;
+ } else if (sysfs_streq(page, "as-is")) {
+ entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN |
+ GPIO_PULL_DISABLE);
+ } else {
+ count = -EINVAL;
+ }
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, pull);
+
+static ssize_t
+gpio_virtuser_lookup_entry_config_active_low_show(struct config_item *item,
+ char *page)
+{
+ enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
+
+ return sprintf(page, "%c\n", flags & GPIO_ACTIVE_LOW ? '1' : '0');
+}
+
+static ssize_t
+gpio_virtuser_lookup_entry_config_active_low_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;
+ bool active_low;
+ int ret;
+
+ ret = kstrtobool(page, &active_low);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_virtuser_device_is_live(dev))
+ return -EBUSY;
+
+ if (active_low)
+ entry->flags |= GPIO_ACTIVE_LOW;
+ else
+ entry->flags &= ~GPIO_ACTIVE_LOW;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, active_low);
+
+static ssize_t
+gpio_virtuser_lookup_entry_config_transitory_show(struct config_item *item,
+ char *page)
+{
+ enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
+
+ return sprintf(page, "%c\n", flags & GPIO_TRANSITORY ? '1' : '0');
+}
+
+static ssize_t
+gpio_virtuser_lookup_entry_config_transitory_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;
+ bool transitory;
+ int ret;
+
+ ret = kstrtobool(page, &transitory);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_virtuser_device_is_live(dev))
+ return -EBUSY;
+
+ if (transitory)
+ entry->flags |= GPIO_TRANSITORY;
+ else
+ entry->flags &= ~GPIO_TRANSITORY;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, transitory);
+
+static struct configfs_attribute *gpio_virtuser_lookup_entry_config_attrs[] = {
+ &gpio_virtuser_lookup_entry_config_attr_key,
+ &gpio_virtuser_lookup_entry_config_attr_offset,
+ &gpio_virtuser_lookup_entry_config_attr_drive,
+ &gpio_virtuser_lookup_entry_config_attr_pull,
+ &gpio_virtuser_lookup_entry_config_attr_active_low,
+ &gpio_virtuser_lookup_entry_config_attr_transitory,
+ NULL
+};
+
+static ssize_t
+gpio_virtuser_device_config_dev_name_show(struct config_item *item,
+ char *page)
+{
+ struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
+ struct platform_device *pdev;
+
+ guard(mutex)(&dev->lock);
+
+ pdev = dev->pdev;
+ if (pdev)
+ return sprintf(page, "%s\n", dev_name(&pdev->dev));
+
+ return sprintf(page, "gpio-sim.%d\n", dev->id);
+}
+
+CONFIGFS_ATTR_RO(gpio_virtuser_device_config_, dev_name);
+
+static ssize_t gpio_virtuser_device_config_live_show(struct config_item *item,
+ char *page)
+{
+ struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
+ bool live;
+
+ scoped_guard(mutex, &dev->lock)
+ live = gpio_virtuser_device_is_live(dev);
+
+ return sprintf(page, "%c\n", live ? '1' : '0');
+}
+
+static size_t
+gpio_virtuser_get_lookup_count(struct gpio_virtuser_device *dev)
+{
+ struct gpio_virtuser_lookup *lookup;
+ size_t count = 0;
+
+ lockdep_assert_held(&dev->lock);
+
+ list_for_each_entry(lookup, &dev->lookup_list, siblings)
+ count += list_count_nodes(&lookup->entry_list);
+
+ return count;
+}
+
+static int
+gpio_virtuser_make_lookup_table(struct gpio_virtuser_device *dev)
+{
+ size_t num_entries = gpio_virtuser_get_lookup_count(dev);
+ struct gpio_virtuser_lookup_entry *entry;
+ struct gpio_virtuser_lookup *lookup;
+ struct gpiod_lookup *curr;
+ unsigned int i = 0;
+
+ lockdep_assert_held(&dev->lock);
+
+ struct gpiod_lookup_table *table __free(kfree) =
+ kzalloc(struct_size(table, table, num_entries + 1), GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ table->dev_id = kasprintf(GFP_KERNEL, "gpio-virtuser.%d", dev->id);
+ if (!table->dev_id)
+ return -ENOMEM;
+
+ list_for_each_entry(lookup, &dev->lookup_list, siblings) {
+ list_for_each_entry(entry, &lookup->entry_list, siblings) {
+ curr = &table->table[i];
+
+ curr->con_id = lookup->con_id;
+ curr->idx = i;
+ curr->key = entry->key;
+ curr->chip_hwnum = entry->offset < 0 ?
+ U16_MAX : entry->offset;
+ curr->flags = entry->flags;
+ i++;
+ }
+ }
+
+ gpiod_add_lookup_table(table);
+ dev->lookup_table = no_free_ptr(table);
+
+ return 0;
+}
+
+static struct fwnode_handle *
+gpio_virtuser_make_device_swnode(struct gpio_virtuser_device *dev)
+{
+ struct property_entry properties[2];
+ struct gpio_virtuser_lookup *lookup;
+ unsigned int i = 0;
+ size_t num_ids;
+
+ memset(properties, 0, sizeof(properties));
+
+ num_ids = list_count_nodes(&dev->lookup_list);
+ char **ids __free(kfree) = kcalloc(num_ids + 1, sizeof(*ids),
+ GFP_KERNEL);
+ if (!ids)
+ return ERR_PTR(-ENOMEM);
+
+ list_for_each_entry(lookup, &dev->lookup_list, siblings)
+ ids[i++] = lookup->con_id;
+
+ properties[0] = PROPERTY_ENTRY_STRING_ARRAY_LEN("gpio-virtuser,ids",
+ ids, num_ids);
+
+ return fwnode_create_software_node(properties, NULL);
+}
+
+static int
+gpio_virtuser_device_activate(struct gpio_virtuser_device *dev)
+{
+ struct platform_device_info pdevinfo;
+ struct fwnode_handle *swnode;
+ struct platform_device *pdev;
+ int ret;
+
+ lockdep_assert_held(&dev->lock);
+
+ if (list_empty(&dev->lookup_list))
+ return -ENODATA;
+
+ swnode = gpio_virtuser_make_device_swnode(dev);
+ if (IS_ERR(swnode))
+ return PTR_ERR(swnode);
+
+ memset(&pdevinfo, 0, sizeof(pdevinfo));
+ pdevinfo.name = "gpio-virtuser";
+ pdevinfo.id = dev->id;
+ pdevinfo.fwnode = swnode;
+
+ ret = gpio_virtuser_make_lookup_table(dev);
+ if (ret) {
+ fwnode_remove_software_node(swnode);
+ return ret;
+ }
+
+ reinit_completion(&dev->probe_completion);
+ dev->driver_bound = false;
+ bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
+
+ pdev = platform_device_register_full(&pdevinfo);
+ if (IS_ERR(pdev)) {
+ bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
+ fwnode_remove_software_node(swnode);
+ return PTR_ERR(pdev);
+ }
+
+ wait_for_completion(&dev->probe_completion);
+ bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
+
+ if (!dev->driver_bound) {
+ platform_device_unregister(pdev);
+ fwnode_remove_software_node(swnode);
+ return -ENXIO;
+ }
+
+ dev->pdev = pdev;
+
+ return 0;
+}
+
+static void
+gpio_virtuser_device_deactivate(struct gpio_virtuser_device *dev)
+{
+ struct fwnode_handle *swnode;
+
+ lockdep_assert_held(&dev->lock);
+
+ swnode = dev_fwnode(&dev->pdev->dev);
+ platform_device_unregister(dev->pdev);
+ fwnode_remove_software_node(swnode);
+ dev->pdev = NULL;
+ gpiod_remove_lookup_table(dev->lookup_table);
+ kfree(dev->lookup_table);
+}
+
+static ssize_t
+gpio_virtuser_device_config_live_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
+ int ret = 0;
+ bool live;
+
+ ret = kstrtobool(page, &live);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (live == gpio_virtuser_device_is_live(dev))
+ return -EPERM;
+
+ if (live)
+ ret = gpio_virtuser_device_activate(dev);
+ else
+ gpio_virtuser_device_deactivate(dev);
+
+ return ret ?: count;
+}
+
+CONFIGFS_ATTR(gpio_virtuser_device_config_, live);
+
+static struct configfs_attribute *gpio_virtuser_device_config_attrs[] = {
+ &gpio_virtuser_device_config_attr_dev_name,
+ &gpio_virtuser_device_config_attr_live,
+ NULL
+};
+
+static void
+gpio_virtuser_lookup_entry_config_group_release(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);
+
+ list_del(&entry->siblings);
+
+ kfree(entry->key);
+ kfree(entry);
+}
+
+static struct
+configfs_item_operations gpio_virtuser_lookup_entry_config_item_ops = {
+ .release = gpio_virtuser_lookup_entry_config_group_release,
+};
+
+static const struct
+config_item_type gpio_virtuser_lookup_entry_config_group_type = {
+ .ct_item_ops = &gpio_virtuser_lookup_entry_config_item_ops,
+ .ct_attrs = gpio_virtuser_lookup_entry_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_group *
+gpio_virtuser_make_lookup_entry_group(struct config_group *group,
+ const char *name)
+{
+ struct gpio_virtuser_lookup *lookup =
+ to_gpio_virtuser_lookup(&group->cg_item);
+ struct gpio_virtuser_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_virtuser_device_is_live(dev))
+ return ERR_PTR(-EBUSY);
+
+ struct gpio_virtuser_lookup_entry *entry __free(kfree) =
+ kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return ERR_PTR(-ENOMEM);
+
+ config_group_init_type_name(&entry->group, name,
+ &gpio_virtuser_lookup_entry_config_group_type);
+ entry->flags = GPIO_LOOKUP_FLAGS_DEFAULT;
+ entry->parent = lookup;
+ list_add_tail(&entry->siblings, &lookup->entry_list);
+
+ return &no_free_ptr(entry)->group;
+}
+
+static void gpio_virtuser_lookup_config_group_release(struct config_item *item)
+{
+ struct gpio_virtuser_lookup *lookup = to_gpio_virtuser_lookup(item);
+ struct gpio_virtuser_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ list_del(&lookup->siblings);
+
+ kfree(lookup->con_id);
+ kfree(lookup);
+}
+
+static struct configfs_item_operations gpio_virtuser_lookup_config_item_ops = {
+ .release = gpio_virtuser_lookup_config_group_release,
+};
+
+static struct
+configfs_group_operations gpio_virtuser_lookup_config_group_ops = {
+ .make_group = gpio_virtuser_make_lookup_entry_group,
+};
+
+static const struct config_item_type gpio_virtuser_lookup_config_group_type = {
+ .ct_group_ops = &gpio_virtuser_lookup_config_group_ops,
+ .ct_item_ops = &gpio_virtuser_lookup_config_item_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_group *
+gpio_virtuser_make_lookup_group(struct config_group *group, const char *name)
+{
+ struct gpio_virtuser_device *dev =
+ to_gpio_virtuser_device(&group->cg_item);
+
+ if (strlen(name) > (GPIO_VIRTUSER_NAME_BUF_LEN - 1))
+ return ERR_PTR(-E2BIG);
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_virtuser_device_is_live(dev))
+ return ERR_PTR(-EBUSY);
+
+ struct gpio_virtuser_lookup *lookup __free(kfree) =
+ kzalloc(sizeof(*lookup), GFP_KERNEL);
+ if (!lookup)
+ return ERR_PTR(-ENOMEM);
+
+ lookup->con_id = kstrdup(name, GFP_KERNEL);
+ if (!lookup->con_id)
+ return ERR_PTR(-ENOMEM);
+
+ config_group_init_type_name(&lookup->group, name,
+ &gpio_virtuser_lookup_config_group_type);
+ INIT_LIST_HEAD(&lookup->entry_list);
+ lookup->parent = dev;
+ list_add_tail(&lookup->siblings, &dev->lookup_list);
+
+ return &no_free_ptr(lookup)->group;
+}
+
+static void gpio_virtuser_device_config_group_release(struct config_item *item)
+{
+ struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_virtuser_device_is_live(dev))
+ gpio_virtuser_device_deactivate(dev);
+
+ mutex_destroy(&dev->lock);
+ ida_free(&gpio_virtuser_ida, dev->id);
+ kfree(dev);
+}
+
+static struct configfs_item_operations gpio_virtuser_device_config_item_ops = {
+ .release = gpio_virtuser_device_config_group_release,
+};
+
+static struct configfs_group_operations gpio_virtuser_device_config_group_ops = {
+ .make_group = gpio_virtuser_make_lookup_group,
+};
+
+static const struct config_item_type gpio_virtuser_device_config_group_type = {
+ .ct_group_ops = &gpio_virtuser_device_config_group_ops,
+ .ct_item_ops = &gpio_virtuser_device_config_item_ops,
+ .ct_attrs = gpio_virtuser_device_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_group *
+gpio_virtuser_config_make_device_group(struct config_group *group,
+ const char *name)
+{
+ struct gpio_virtuser_device *dev __free(kfree) = kzalloc(sizeof(*dev),
+ GFP_KERNEL);
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ dev->id = ida_alloc(&gpio_virtuser_ida, GFP_KERNEL);
+ if (dev->id < 0)
+ return ERR_PTR(dev->id);
+
+ config_group_init_type_name(&dev->group, name,
+ &gpio_virtuser_device_config_group_type);
+ mutex_init(&dev->lock);
+ INIT_LIST_HEAD(&dev->lookup_list);
+ dev->bus_notifier.notifier_call = gpio_virtuser_bus_notifier_call;
+ init_completion(&dev->probe_completion);
+
+ return &no_free_ptr(dev)->group;
+}
+
+static struct configfs_group_operations gpio_virtuser_config_group_ops = {
+ .make_group = gpio_virtuser_config_make_device_group,
+};
+
+static const struct config_item_type gpio_virtuser_config_type = {
+ .ct_group_ops = &gpio_virtuser_config_group_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem gpio_virtuser_config_subsys = {
+ .su_group = {
+ .cg_item = {
+ .ci_namebuf = "gpio-virtuser",
+ .ci_type = &gpio_virtuser_config_type,
+ },
+ },
+};
+
+static int __init gpio_virtuser_init(void)
+{
+ int ret;
+
+ ret = platform_driver_register(&gpio_virtuser_driver);
+ if (ret) {
+ pr_err("Failed to register the platform driver: %d\n", ret);
+ return ret;
+ }
+
+ config_group_init(&gpio_virtuser_config_subsys.su_group);
+ mutex_init(&gpio_virtuser_config_subsys.su_mutex);
+ ret = configfs_register_subsystem(&gpio_virtuser_config_subsys);
+ if (ret) {
+ pr_err("Failed to register the '%s' configfs subsystem: %d\n",
+ gpio_virtuser_config_subsys.su_group.cg_item.ci_namebuf,
+ ret);
+ goto err_plat_drv_unreg;
+ }
+
+ gpio_virtuser_dbg_root = debugfs_create_dir("gpio-virtuser", NULL);
+ if (IS_ERR(gpio_virtuser_dbg_root)) {
+ ret = PTR_ERR(gpio_virtuser_dbg_root);
+ pr_err("Failed to create the debugfs tree: %d\n", ret);
+ goto err_configfs_unreg;
+ }
+
+ return 0;
+
+err_configfs_unreg:
+ configfs_unregister_subsystem(&gpio_virtuser_config_subsys);
+err_plat_drv_unreg:
+ mutex_destroy(&gpio_virtuser_config_subsys.su_mutex);
+ platform_driver_unregister(&gpio_virtuser_driver);
+
+ return ret;
+}
+module_init(gpio_virtuser_init);
+
+static void __exit gpio_virtuser_exit(void)
+{
+ configfs_unregister_subsystem(&gpio_virtuser_config_subsys);
+ mutex_destroy(&gpio_virtuser_config_subsys.su_mutex);
+ platform_driver_unregister(&gpio_virtuser_driver);
+ debugfs_remove_recursive(gpio_virtuser_dbg_root);
+}
+module_exit(gpio_virtuser_exit);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_DESCRIPTION("Virtual GPIO consumer module");
+MODULE_LICENSE("GPL");