new file mode 100644
@@ -0,0 +1,111 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Virtual GPIO Consumer
+=====================
+
+The virtual GPIO Consumer module allows users to create dynamic GPIO lookup
+tables using the exposed configfs interface and instantiate virtual GPIO
+consumer devices that retrieve and use GPIOs using these tables.
+
+Creating GPIO consumers
+-----------------------
+
+The gpio-consumer module registers a configfs subsystem called
+``'gpio-consumer'``. 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-consumer``
+
+This is the top directory of the gpio-consumer configfs tree.
+
+**Group:** ``/config/gpio-consumer/consumer-device``
+
+**Attribute:** ``/config/gpio-consumer/gpio-device/function``
+
+**Attribute:** ``/config/gpio-consumer/gpio-device/live``
+
+This is a directory representing a GPIO consumer device. The ``'function'``
+attribute defines how the device will use requested GPIOs. It takes the
+following values: ``'active'`` - GPIOs will be requested as output-high and
+kept in this state until the device is unbound, ``'toggle'`` - GPIOs will
+be requested in output mode and then toggled periodically (every second)
+between 1 and 0, ``'monitor'`` - GPIOs will be requested in input mode, then
+requested as interrupts and their firing reported in the kernel log.
+
+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
+---------------------------
+
+User can create a number of configfs groups under the device group with the
+following properties:
+
+**Group:** ``/config/gpio-consumer/consumer-device/lookupX``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/key``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/offset``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/drive``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/pull``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/active_low``
+
+**Attribute:** ``/config/gpio-consumer/consumer-device/lookupX/transitory``
+
+This group represents a single entry in the GPIO lookup table. The name of the
+sub-directory maps to the ``'con_id'`` field of ``'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 devices. 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-virtual-consumer"``. Supported properties are:
+
+ ``"gpio-virtual-consumer,function"`` - function of the virtual device
+ ``"gpio-virtual-consumer,lines"`` - list of lookup keys
+
+An example device-tree code defining a virtual GPIO consumer:
+
+.. code-block :: none
+
+ gpio-virt-consumer {
+ compatible = "gpio-virtual-consumer";
+
+ foo-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
+ bar-gpios = <&gpio0 6 0>;
+
+ gpio-virtual-consumer,function = "toggle";
+ gpio-virtual-consumer,lines = "foo", "bar";
+ };
+
+.. SPDX-License-Identifier: GPL-2.0-or-later
@@ -8,6 +8,7 @@ gpio
:maxdepth: 1
gpio-aggregator
+ gpio-consumer
sysfs
gpio-mockup
gpio-sim
@@ -1762,6 +1762,13 @@ config GPIO_AGGREGATOR
industrial control context, to be operated from userspace using
the GPIO chardev interface.
+config GPIO_CONSUMER
+ tristate "GPIO Consumer Testing Module"
+ select CONFIGFS_FS
+ help
+ This enables the configurable, configfs-based virtual GPIO consumer
+ testing driver.
+
config GPIO_LATCH
tristate "GPIO latch driver"
help
@@ -46,6 +46,7 @@ obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
obj-$(CONFIG_GPIO_CADENCE) += gpio-cadence.o
obj-$(CONFIG_GPIO_CLPS711X) += gpio-clps711x.o
obj-$(CONFIG_GPIO_SNPS_CREG) += gpio-creg-snps.o
+obj-$(CONFIG_GPIO_CONSUMER) += gpio-consumer.o
obj-$(CONFIG_GPIO_CRYSTAL_COVE) += gpio-crystalcove.o
obj-$(CONFIG_GPIO_CS5535) += gpio-cs5535.o
obj-$(CONFIG_GPIO_DA9052) += gpio-da9052.o
new file mode 100644
@@ -0,0 +1,946 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Configurable virtual GPIO consumer module.
+ *
+ * Copyright (C) 2023 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cleanup.h>
+#include <linux/completion.h>
+#include <linux/configfs.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/machine.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/list.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.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.h>
+#include <linux/timer.h>
+
+#include "gpiolib.h"
+
+#define GPIO_CONSUMER_MAX_PROPS 3
+
+enum gpio_consumer_function {
+ GPIO_CONSUMER_FUNCTION_ACTIVE = 0,
+ GPIO_CONSUMER_FUNCTION_TOGGLE,
+ GPIO_CONSUMER_FUNCTION_MONITOR,
+ __GPIO_CONSUMER_FUNCTION_LAST
+};
+
+static const char *const gpio_consumer_function_strings[] = {
+ [GPIO_CONSUMER_FUNCTION_ACTIVE] = "active",
+ [GPIO_CONSUMER_FUNCTION_TOGGLE] = "toggle",
+ [GPIO_CONSUMER_FUNCTION_MONITOR] = "monitor",
+ NULL
+};
+
+struct gpio_consumer_irq_data {
+ struct device *dev;
+ struct gpio_desc *desc;
+};
+
+struct gpio_consumer_timer_data {
+ struct timer_list timer;
+ struct gpio_desc *desc;
+ int val;
+};
+
+static struct gpio_consumer_timer_data *to_timer_data(struct timer_list *timer)
+{
+ return container_of(timer, struct gpio_consumer_timer_data, timer);
+}
+
+static DEFINE_IDA(gpio_consumer_ida);
+
+static irqreturn_t gpio_consumer_on_irq(int irq, void *data)
+{
+ struct gpio_consumer_irq_data *irq_data = data;
+ struct gpio_desc *desc = irq_data->desc;
+ struct gpio_device *gdev = desc->gdev;
+ struct device *dev = irq_data->dev;
+ int val;
+
+ val = gpiod_get_value_cansleep(desc);
+ if (val < 0) {
+ dev_err(dev, "failed to read GPIO value: %d\n", val);
+ return IRQ_HANDLED;
+ }
+
+ dev_info(dev, "interrupt triggered on line %u of %s, new value: %d\n",
+ gpio_chip_hwgpio(desc), dev_name(&gdev->dev), val);
+
+ return IRQ_HANDLED;
+}
+
+static void gpio_consumer_on_timer(struct timer_list *timer)
+{
+ struct gpio_consumer_timer_data *timer_data = to_timer_data(timer);
+
+ timer_data->val = timer_data->val ? 0 : 1;
+ gpiod_set_value_cansleep(timer_data->desc, timer_data->val);
+ mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(1000));
+}
+
+static void gpio_consumer_del_timer(void *data)
+{
+ struct timer_list *timer = data;
+
+ del_timer(timer);
+}
+
+static int gpio_consumer_probe(struct platform_device *pdev)
+{
+ struct gpio_consumer_timer_data *timer_data;
+ struct gpio_consumer_irq_data *irq_data;
+ enum gpio_consumer_function function;
+ const char *function_prop, **lines;
+ struct device *dev = &pdev->dev;
+ struct gpio_desc *desc;
+ enum gpiod_flags flags;
+ int ret, num_lines, i;
+
+ ret = device_property_read_string(dev, "gpio-virtual-consumer,function",
+ &function_prop);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to read the consumer GPIO function\n");
+
+ ret = match_string(gpio_consumer_function_strings, -1, function_prop);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Invalid consumer function: '%s'\n",
+ function_prop);
+
+ function = ret;
+ num_lines = device_property_string_array_count(dev,
+ "gpio-virtual-consumer,lines");
+ if (num_lines < 0)
+ return dev_err_probe(dev, num_lines,
+ "List of GPIO lines to request not found\n");
+
+ lines = devm_kcalloc(dev, num_lines, sizeof(*lines), GFP_KERNEL);
+ if (!lines)
+ return -ENOMEM;
+
+ ret = device_property_read_string_array(dev,
+ "gpio-virtual-consumer,lines",
+ lines, num_lines);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Failed to read GPIO line names\n");
+
+ flags = function == GPIO_CONSUMER_FUNCTION_MONITOR ?
+ GPIOD_IN : GPIOD_OUT_HIGH;
+ for (i = 0; i < num_lines; i++) {
+ desc = devm_gpiod_get(dev, lines[i], flags);
+ if (IS_ERR(desc))
+ return dev_err_probe(dev, PTR_ERR(desc),
+ "Failed to get GPIO '%s'\n",
+ lines[i]);
+
+ if (function == GPIO_CONSUMER_FUNCTION_MONITOR) {
+ irq_data = devm_kzalloc(dev, sizeof(*irq_data),
+ GFP_KERNEL);
+ if (!irq_data)
+ return -ENOMEM;
+
+ irq_data->dev = dev;
+ irq_data->desc = desc;
+
+ ret = devm_request_threaded_irq(dev, gpiod_to_irq(desc),
+ NULL,
+ gpio_consumer_on_irq,
+ IRQF_TRIGGER_FALLING |
+ IRQF_TRIGGER_RISING |
+ IRQF_ONESHOT,
+ lines[i], irq_data);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to request GPIO line interrupt\n");
+ } else if (function == GPIO_CONSUMER_FUNCTION_TOGGLE) {
+ timer_data = devm_kzalloc(dev, sizeof(*timer_data),
+ GFP_KERNEL);
+ if (!timer_data)
+ return -ENOMEM;
+
+ timer_data->desc = desc;
+ timer_data->val = 1;
+
+ timer_setup(&timer_data->timer,
+ gpio_consumer_on_timer, 0);
+ mod_timer(&timer_data->timer,
+ jiffies + msecs_to_jiffies(1000));
+
+ ret = devm_add_action_or_reset(dev,
+ gpio_consumer_del_timer,
+ &timer_data->timer);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static const struct of_device_id gpio_consumer_of_match[] = {
+ { .compatible = "gpio-virtual-consumer" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, gpio_consumer_of_match);
+
+static struct platform_driver gpio_consumer_driver = {
+ .driver = {
+ .name = "gpio-virtual-consumer",
+ .of_match_table = gpio_consumer_of_match,
+ },
+ .probe = gpio_consumer_probe,
+};
+
+struct gpio_consumer_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;
+ enum gpio_consumer_function function;
+
+ struct list_head lookup_list;
+};
+
+static int gpio_consumer_bus_notifier_call(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct gpio_consumer_device *consumer;
+ struct device *dev = data;
+ char devname[32];
+
+ consumer = container_of(nb, struct gpio_consumer_device, bus_notifier);
+ snprintf(devname, sizeof(devname), "gpio-virtual-consumer.%d",
+ consumer->id);
+
+ if (strcmp(dev_name(dev), devname))
+ return NOTIFY_DONE;
+
+ switch (action) {
+ case BUS_NOTIFY_BOUND_DRIVER:
+ consumer->driver_bound = true;
+ break;
+ case BUS_NOTIFY_DRIVER_NOT_BOUND:
+ consumer->driver_bound = false;
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ complete(&consumer->probe_completion);
+ return NOTIFY_OK;
+}
+
+static struct gpio_consumer_device *
+to_gpio_consumer_device(struct config_item *item)
+{
+ struct config_group *group = to_config_group(item);
+
+ return container_of(group, struct gpio_consumer_device, group);
+}
+
+static bool
+gpio_consumer_device_is_live_unlocked(struct gpio_consumer_device *dev)
+{
+ return !!dev->pdev;
+}
+
+struct gpio_consumer_lookup {
+ struct config_group group;
+
+ struct gpio_consumer_device *parent;
+ struct list_head siblings;
+
+ char *con_id;
+ char *key;
+ /* Can be negative to indicate lookup by name. */
+ int offset;
+
+ enum gpio_lookup_flags flags;
+};
+
+static struct gpio_consumer_lookup *
+to_gpio_consumer_lookup(struct config_item *item)
+{
+ struct config_group *group = to_config_group(item);
+
+ return container_of(group, struct gpio_consumer_lookup, group);
+}
+
+static ssize_t
+gpio_consumer_lookup_config_key_show(struct config_item *item, char *page)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ return sprintf(page, "%s\n", lookup->key);
+}
+
+static ssize_t
+gpio_consumer_lookup_config_key_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+ char *key __free(kfree) = NULL;
+
+ key = kstrndup(skip_spaces(page), count, GFP_KERNEL);
+ if (!key)
+ return -ENOMEM;
+
+ strim(key);
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ kfree(lookup->key);
+ lookup->key = no_free_ptr(key);
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, key);
+
+static ssize_t
+gpio_consumer_lookup_config_offset_show(struct config_item *item, char *page)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+ unsigned int offset;
+
+ scoped_guard(mutex, &dev->lock)
+ offset = lookup->offset;
+
+ return sprintf(page, "%d\n", offset);
+}
+
+static ssize_t
+gpio_consumer_lookup_config_offset_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->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_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ lookup->offset = offset;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, offset);
+
+static enum gpio_lookup_flags
+gpio_consumer_lookup_get_flags(struct config_item *item)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ return lookup->flags;
+}
+
+static ssize_t
+gpio_consumer_lookup_config_drive_show(struct config_item *item, char *page)
+{
+ enum gpio_lookup_flags flags = gpio_consumer_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_consumer_lookup_config_drive_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ if (sysfs_streq(page, "push-pull")) {
+ lookup->flags &= ~(GPIO_OPEN_DRAIN | GPIO_OPEN_SOURCE);
+ } else if (sysfs_streq(page, "open-drain")) {
+ lookup->flags &= ~GPIO_OPEN_SOURCE;
+ lookup->flags |= GPIO_OPEN_DRAIN;
+ } else if (sysfs_streq(page, "open-source")) {
+ lookup->flags &= ~GPIO_OPEN_DRAIN;
+ lookup->flags |= GPIO_OPEN_SOURCE;
+ } else {
+ count = -EINVAL;
+ }
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, drive);
+
+static ssize_t
+gpio_consumer_lookup_config_pull_show(struct config_item *item, char *page)
+{
+ enum gpio_lookup_flags flags = gpio_consumer_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_consumer_lookup_config_pull_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ if (sysfs_streq(page, "pull-up")) {
+ lookup->flags &= ~(GPIO_PULL_DOWN | GPIO_PULL_DISABLE);
+ lookup->flags |= GPIO_PULL_UP;
+ } else if (sysfs_streq(page, "pull-down")) {
+ lookup->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DISABLE);
+ lookup->flags |= GPIO_PULL_DOWN;
+ } else if (sysfs_streq(page, "pull-disabled")) {
+ lookup->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN);
+ lookup->flags |= GPIO_PULL_DISABLE;
+ } else if (sysfs_streq(page, "as-is")) {
+ lookup->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN |
+ GPIO_PULL_DISABLE);
+ } else {
+ count = -EINVAL;
+ }
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, pull);
+
+static ssize_t
+gpio_consumer_lookup_config_active_low_show(struct config_item *item,
+ char *page)
+{
+ enum gpio_lookup_flags flags = gpio_consumer_lookup_get_flags(item);
+
+ return sprintf(page, "%s\n", flags & GPIO_ACTIVE_LOW ? "1" : "0");
+}
+
+static ssize_t
+gpio_consumer_lookup_config_active_low_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+ bool active_low;
+ int ret;
+
+ ret = kstrtobool(page, &active_low);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ if (active_low)
+ lookup->flags |= GPIO_ACTIVE_LOW;
+ else
+ lookup->flags &= ~GPIO_ACTIVE_LOW;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, active_low);
+
+static ssize_t
+gpio_consumer_lookup_config_transitory_show(struct config_item *item,
+ char *page)
+{
+ enum gpio_lookup_flags flags = gpio_consumer_lookup_get_flags(item);
+
+ return sprintf(page, "%s\n", flags & GPIO_TRANSITORY ? "1" : "0");
+}
+
+static ssize_t
+gpio_consumer_lookup_config_transitory_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+ bool transitory;
+ int ret;
+
+ ret = kstrtobool(page, &transitory);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ if (transitory)
+ lookup->flags |= GPIO_TRANSITORY;
+ else
+ lookup->flags &= ~GPIO_TRANSITORY;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_lookup_config_, transitory);
+
+static struct configfs_attribute *gpio_consumer_lookup_config_attrs[] = {
+ &gpio_consumer_lookup_config_attr_key,
+ &gpio_consumer_lookup_config_attr_offset,
+ &gpio_consumer_lookup_config_attr_drive,
+ &gpio_consumer_lookup_config_attr_pull,
+ &gpio_consumer_lookup_config_attr_active_low,
+ &gpio_consumer_lookup_config_attr_transitory,
+ NULL
+};
+
+static ssize_t gpio_consumer_device_config_live_show(struct config_item *item,
+ char *page)
+{
+ struct gpio_consumer_device *dev = to_gpio_consumer_device(item);
+ bool live;
+
+ scoped_guard(mutex, &dev->lock)
+ live = gpio_consumer_device_is_live_unlocked(dev);
+
+ return sprintf(page, "%c\n", live ? '1' : '0');
+}
+
+static int
+gpio_consumer_make_lookup_table_unlocked(struct gpio_consumer_device *dev)
+{
+ struct gpiod_lookup_table *table __free(kfree) = NULL;
+ struct gpio_consumer_lookup *lookup;
+ struct gpiod_lookup *curr;
+ size_t num_entries;
+ unsigned int i = 0;
+
+ num_entries = list_count_nodes(&dev->lookup_list);
+ table = kzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ table->dev_id = kasprintf(GFP_KERNEL, "gpio-virtual-consumer.%d",
+ dev->id);
+ if (!table->dev_id)
+ return -ENOMEM;
+
+ list_for_each_entry(lookup, &dev->lookup_list, siblings) {
+ curr = &table->table[i];
+
+ curr->key = lookup->key;
+ curr->chip_hwnum = lookup->offset < 0 ?
+ U16_MAX : lookup->offset;
+ curr->con_id = lookup->con_id;
+ curr->flags = lookup->flags;
+ }
+
+ gpiod_add_lookup_table(table);
+ dev->lookup_table = no_free_ptr(table);
+
+ return 0;
+}
+
+static struct fwnode_handle *
+gpio_consumer_make_device_swnode(struct gpio_consumer_device *dev)
+{
+ struct property_entry properties[GPIO_CONSUMER_MAX_PROPS];
+ struct gpio_consumer_lookup *lookup;
+ char **lines __free(kfree) = NULL;
+ int prop_idx = 0, i = 0;
+ size_t num_lookups;
+
+ memset(properties, 0, sizeof(properties));
+
+ properties[prop_idx++] = PROPERTY_ENTRY_STRING(
+ "gpio-virtual-consumer,function",
+ gpio_consumer_function_strings[dev->function]);
+
+ num_lookups = list_count_nodes(&dev->lookup_list);
+ lines = kcalloc(num_lookups + 1, sizeof(*lines), GFP_KERNEL);
+ if (!lines)
+ return ERR_PTR(-ENOMEM);
+
+ list_for_each_entry(lookup, &dev->lookup_list, siblings)
+ lines[i++] = lookup->con_id;
+
+ properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
+ "gpio-virtual-consumer,lines", lines, num_lookups);
+
+ return fwnode_create_software_node(properties, NULL);
+}
+
+static int
+gpio_consumer_device_activate_unlocked(struct gpio_consumer_device *dev)
+{
+ struct platform_device_info pdevinfo;
+ struct fwnode_handle *swnode;
+ struct platform_device *pdev;
+ int ret;
+
+ if (list_empty(&dev->lookup_list))
+ return -ENODATA;
+
+ swnode = gpio_consumer_make_device_swnode(dev);
+ if (IS_ERR(swnode))
+ return PTR_ERR(swnode);
+
+ memset(&pdevinfo, 0, sizeof(pdevinfo));
+ pdevinfo.name = "gpio-virtual-consumer";
+ pdevinfo.id = dev->id;
+ pdevinfo.fwnode = swnode;
+
+ ret = gpio_consumer_make_lookup_table_unlocked(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_consumer_device_deactivate_unlocked(struct gpio_consumer_device *dev)
+{
+ struct fwnode_handle *swnode;
+
+ 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_consumer_device_config_live_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_device *dev = to_gpio_consumer_device(item);
+ bool live;
+ int ret;
+
+ ret = kstrtobool(page, &live);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ if (live == gpio_consumer_device_is_live_unlocked(dev))
+ ret = -EPERM;
+ else if (live)
+ ret = gpio_consumer_device_activate_unlocked(dev);
+ else
+ gpio_consumer_device_deactivate_unlocked(dev);
+
+ return ret ?: count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_device_config_, live);
+
+static ssize_t
+gpio_consumer_device_config_function_show(struct config_item *item, char *page)
+{
+ struct gpio_consumer_device *dev = to_gpio_consumer_device(item);
+ enum gpio_consumer_function function;
+ const char *repr;
+
+ scoped_guard(mutex, &dev->lock)
+ function = dev->function;
+
+ repr = gpio_consumer_function_strings[function];
+
+ return sprintf(page, "%s\n", repr);
+}
+
+static ssize_t
+gpio_consumer_device_config_function_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_consumer_device *dev = to_gpio_consumer_device(item);
+ int ret;
+
+ ret = sysfs_match_string(gpio_consumer_function_strings, page);
+ if (ret < 0)
+ return -EINVAL;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return -EBUSY;
+
+ dev->function = ret;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_consumer_device_config_, function);
+
+static struct configfs_attribute *gpio_consumer_device_config_attrs[] = {
+ &gpio_consumer_device_config_attr_live,
+ &gpio_consumer_device_config_attr_function,
+ NULL
+};
+
+static void gpio_consumer_lookup_config_group_release(struct config_item *item)
+{
+ struct gpio_consumer_lookup *lookup = to_gpio_consumer_lookup(item);
+ struct gpio_consumer_device *dev = lookup->parent;
+
+ guard(mutex)(&dev->lock);
+
+ list_del(&lookup->siblings);
+
+ kfree(lookup->con_id);
+ kfree(lookup->key);
+ kfree(lookup);
+}
+
+static struct configfs_item_operations gpio_consumer_lookup_config_item_ops = {
+ .release = gpio_consumer_lookup_config_group_release,
+};
+
+static const struct config_item_type gpio_consumer_lookup_config_group_type = {
+ .ct_item_ops = &gpio_consumer_lookup_config_item_ops,
+ .ct_attrs = gpio_consumer_lookup_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_group *
+gpio_consumer_device_make_lookup_group(struct config_group *group,
+ const char *name)
+{
+ struct gpio_consumer_device *dev =
+ to_gpio_consumer_device(&group->cg_item);
+ struct gpio_consumer_lookup *lookup __free(kfree) = NULL;
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ return ERR_PTR(-EBUSY);
+
+ lookup = 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_consumer_lookup_config_group_type);
+ lookup->flags = GPIO_LOOKUP_FLAGS_DEFAULT;
+ lookup->parent = dev;
+ list_add_tail(&lookup->siblings, &dev->lookup_list);
+
+ return &no_free_ptr(lookup)->group;
+}
+
+static void gpio_consumer_device_config_group_release(struct config_item *item)
+{
+ struct gpio_consumer_device *dev = to_gpio_consumer_device(item);
+
+ guard(mutex)(&dev->lock);
+
+ if (gpio_consumer_device_is_live_unlocked(dev))
+ gpio_consumer_device_deactivate_unlocked(dev);
+
+ mutex_destroy(&dev->lock);
+ ida_free(&gpio_consumer_ida, dev->id);
+ kfree(dev);
+}
+
+static struct configfs_item_operations gpio_consumer_device_config_item_ops = {
+ .release = gpio_consumer_device_config_group_release,
+};
+
+static struct configfs_group_operations gpio_consumer_device_config_group_ops = {
+ .make_group = gpio_consumer_device_make_lookup_group,
+};
+
+static const struct config_item_type gpio_consumer_device_config_group_type = {
+ .ct_group_ops = &gpio_consumer_device_config_group_ops,
+ .ct_item_ops = &gpio_consumer_device_config_item_ops,
+ .ct_attrs = gpio_consumer_device_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_group *
+gpio_consumer_config_make_device_group(struct config_group *group,
+ const char *name)
+{
+ struct gpio_consumer_device *dev __free(kfree) = NULL;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ dev->id = ida_alloc(&gpio_consumer_ida, GFP_KERNEL);
+ if (dev->id < 0)
+ return ERR_PTR(dev->id);
+
+ config_group_init_type_name(&dev->group, name,
+ &gpio_consumer_device_config_group_type);
+ mutex_init(&dev->lock);
+ INIT_LIST_HEAD(&dev->lookup_list);
+ dev->bus_notifier.notifier_call = gpio_consumer_bus_notifier_call;
+ dev->function = GPIO_CONSUMER_FUNCTION_ACTIVE;
+ init_completion(&dev->probe_completion);
+
+ return &no_free_ptr(dev)->group;
+}
+
+static struct configfs_group_operations gpio_consumer_config_group_ops = {
+ .make_group = gpio_consumer_config_make_device_group,
+};
+
+static const struct config_item_type gpio_consumer_config_type = {
+ .ct_group_ops = &gpio_consumer_config_group_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem gpio_consumer_config_subsys = {
+ .su_group = {
+ .cg_item = {
+ .ci_namebuf = "gpio-consumer",
+ .ci_type = &gpio_consumer_config_type,
+ },
+ },
+};
+
+static int __init gpio_consumer_init(void)
+{
+ int ret;
+
+ ret = platform_driver_register(&gpio_consumer_driver);
+ if (ret) {
+ pr_err("Failed to register the platform driver: %d\n",
+ ret);
+ return ret;
+ }
+
+ config_group_init(&gpio_consumer_config_subsys.su_group);
+ mutex_init(&gpio_consumer_config_subsys.su_mutex);
+ ret = configfs_register_subsystem(&gpio_consumer_config_subsys);
+ if (ret) {
+ pr_err("Failed to register the '%s' configfs subsystem: %d\n",
+ gpio_consumer_config_subsys.su_group.cg_item.ci_namebuf,
+ ret);
+ mutex_destroy(&gpio_consumer_config_subsys.su_mutex);
+ platform_driver_unregister(&gpio_consumer_driver);
+ return ret;
+ }
+
+ return 0;
+}
+module_init(gpio_consumer_init);
+
+static void __exit gpio_consumer_exit(void)
+{
+ configfs_unregister_subsystem(&gpio_consumer_config_subsys);
+ mutex_destroy(&gpio_consumer_config_subsys.su_mutex);
+ platform_driver_unregister(&gpio_consumer_driver);
+}
+module_exit(gpio_consumer_exit);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_DESCRIPTION("Virtual GPIO consumer module");
+MODULE_LICENSE("GPL");