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authorBartosz Golaszewski <bartosz.golaszewski@linaro.org>2024-07-08 16:29:12 +0200
committerBartosz Golaszewski <bartosz.golaszewski@linaro.org>2024-07-09 09:39:54 +0200
commit91581c4b3f29e2e22aeb1a62e842d529ca638b2d (patch)
treea68c8967902a73905f15bd0ad330c27540431f07 /drivers/gpio
parent8060be2489f9bfa0c603373fa71cc2f93e46e462 (diff)
gpio: virtuser: new virtual testing driver for the GPIO API
The GPIO subsystem used to have a serious problem with undefined behavior and use-after-free bugs on hot-unplug of GPIO chips. This can be considered a corner-case by some as most GPIO controllers are enabled early in the boot process and live until the system goes down but most GPIO drivers do allow unbind over sysfs, many are loadable modules that can be (force) unloaded and there are also GPIO devices that can be dynamically detached, for instance CP2112 which is a USB GPIO expender. Bugs can be triggered both from user-space as well as by in-kernel users. We have the means of testing it from user-space via the character device but the issues manifest themselves differently in the kernel. This is a proposition of adding a new virtual driver - a configurable GPIO consumer that can be configured over configfs (similarly to gpio-sim) or described on the device-tree. This driver is aimed as a helper in spotting any regressions in hot-unplug handling in GPIOLIB. Link: https://lore.kernel.org/r/20240708142912.120570-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/Kconfig12
-rw-r--r--drivers/gpio/Makefile1
-rw-r--r--drivers/gpio/gpio-virtuser.c1807
3 files changed, 1820 insertions, 0 deletions
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);
+ 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");