gpio: sim: simplify code with cleanup helpers

Use macros defined in linux/cleanup.h to automate resource lifetime
control in gpio-sim.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-sim.c

@@ -8,6 +8,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/bitmap.h>
+#include <linux/cleanup.h>
 #include <linux/completion.h>
 #include <linux/configfs.h>
 #include <linux/device.h>
@@ -68,7 +69,7 @@ static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
 	gc = &chip->gc;
 	desc = &gc->gpiodev->descs[offset];
 
-	mutex_lock(&chip->lock);
+	guard(mutex)(&chip->lock);
 
 	if (test_bit(FLAG_REQUESTED, &desc->flags) &&
 	    !test_bit(FLAG_IS_OUT, &desc->flags)) {
@@ -104,29 +105,24 @@ static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
 
 set_pull:
 	__assign_bit(offset, chip->pull_map, value);
-	mutex_unlock(&chip->lock);
 	return 0;
 }
 
 static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
-	int ret;
 
-	mutex_lock(&chip->lock);
-	ret = !!test_bit(offset, chip->value_map);
-	mutex_unlock(&chip->lock);
+	guard(mutex)(&chip->lock);
 
-	return ret;
+	return !!test_bit(offset, chip->value_map);
 }
 
 static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__assign_bit(offset, chip->value_map, value);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__assign_bit(offset, chip->value_map, value);
 }
 
 static int gpio_sim_get_multiple(struct gpio_chip *gc,
@@ -134,9 +130,8 @@ static int gpio_sim_get_multiple(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
 
 	return 0;
 }
@@ -146,9 +141,9 @@ static void gpio_sim_set_multiple(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		bitmap_replace(chip->value_map, chip->value_map, bits, mask,
+			       gc->ngpio);
 }
 
 static int gpio_sim_direction_output(struct gpio_chip *gc,
@@ -156,10 +151,10 @@ static int gpio_sim_direction_output(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__clear_bit(offset, chip->direction_map);
-	__assign_bit(offset, chip->value_map, value);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock) {
+		__clear_bit(offset, chip->direction_map);
+		__assign_bit(offset, chip->value_map, value);
+	}
 
 	return 0;
 }
@@ -168,9 +163,8 @@ static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__set_bit(offset, chip->direction_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__set_bit(offset, chip->direction_map);
 
 	return 0;
 }
@@ -180,9 +174,8 @@ static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 	int direction;
 
-	mutex_lock(&chip->lock);
-	direction = !!test_bit(offset, chip->direction_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		direction = !!test_bit(offset, chip->direction_map);
 
 	return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
 }
@@ -215,9 +208,9 @@ static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__assign_bit(offset, chip->value_map,
+			     !!test_bit(offset, chip->pull_map));
 }
 
 static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
@@ -227,9 +220,8 @@ static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
 	struct gpio_sim_chip *chip = dev_get_drvdata(dev);
 	int val;
 
-	mutex_lock(&chip->lock);
-	val = !!test_bit(line_attr->offset, chip->value_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		val = !!test_bit(line_attr->offset, chip->value_map);
 
 	return sysfs_emit(buf, "%d\n", val);
 }
@@ -258,9 +250,8 @@ static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
 	struct gpio_sim_chip *chip = dev_get_drvdata(dev);
 	int pull;
 
-	mutex_lock(&chip->lock);
-	pull = !!test_bit(line_attr->offset, chip->pull_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		pull = !!test_bit(line_attr->offset, chip->pull_map);
 
 	return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
 }
@@ -656,17 +647,14 @@ static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
 {
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 	struct platform_device *pdev;
-	int ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
+
 	pdev = dev->pdev;
 	if (pdev)
-		ret = sprintf(page, "%s\n", dev_name(&pdev->dev));
-	else
-		ret = sprintf(page, "gpio-sim.%d\n", dev->id);
-	mutex_unlock(&dev->lock);
+		return sprintf(page, "%s\n", dev_name(&pdev->dev));
 
-	return ret;
+	return sprintf(page, "gpio-sim.%d\n", dev->id);
 }
 
 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
@@ -677,9 +665,8 @@ gpio_sim_device_config_live_show(struct config_item *item, char *page)
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 	bool live;
 
-	mutex_lock(&dev->lock);
-	live = gpio_sim_device_is_live_unlocked(dev);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		live = gpio_sim_device_is_live_unlocked(dev);
 
 	return sprintf(page, "%c\n", live ? '1' : '0');
 }
@@ -834,8 +821,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 {
 	struct property_entry properties[GPIO_SIM_PROP_MAX];
 	unsigned int prop_idx = 0, line_names_size = 0;
-	struct fwnode_handle *swnode;
-	char **line_names;
+	char **line_names __free(kfree) = NULL;
 
 	memset(properties, 0, sizeof(properties));
 
@@ -854,9 +840,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 						"gpio-line-names",
 						line_names, line_names_size);
 
-	swnode = fwnode_create_software_node(properties, parent);
-	kfree(line_names);
-	return swnode;
+	return fwnode_create_software_node(properties, parent);
 }
 
 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
@@ -981,7 +965,7 @@ gpio_sim_device_config_live_store(struct config_item *item,
 	if (ret)
 		return ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
 	if (live == gpio_sim_device_is_live_unlocked(dev))
 		ret = -EPERM;
@@ -990,8 +974,6 @@ gpio_sim_device_config_live_store(struct config_item *item,
 	else
 		gpio_sim_device_deactivate_unlocked(dev);
 
-	mutex_unlock(&dev->lock);
-
 	return ret ?: count;
 }
 
@@ -1028,17 +1010,14 @@ static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 	struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
-	int ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
+
 	if (gpio_sim_device_is_live_unlocked(dev))
-		ret = device_for_each_child(&dev->pdev->dev, &ctx,
-					    gpio_sim_emit_chip_name);
-	else
-		ret = sprintf(page, "none\n");
-	mutex_unlock(&dev->lock);
+		return device_for_each_child(&dev->pdev->dev, &ctx,
+					     gpio_sim_emit_chip_name);
 
-	return ret;
+	return sprintf(page, "none\n");
 }
 
 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
@@ -1048,13 +1027,10 @@ gpio_sim_bank_config_label_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", bank->label ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", bank->label ?: "");
 }
 
 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
@@ -1064,23 +1040,18 @@ static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(bank->label);
 	bank->label = trimmed;
 
-	mutex_unlock(&dev->lock);
 	return count;
 }
 
@@ -1091,13 +1062,10 @@ gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%u\n", bank->num_lines);
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%u\n", bank->num_lines);
 }
 
 static ssize_t
@@ -1116,16 +1084,13 @@ gpio_sim_bank_config_num_lines_store(struct config_item *item,
 	if (num_lines == 0)
 		return -EINVAL;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	bank->num_lines = num_lines;
 
-	mutex_unlock(&dev->lock);
 	return count;
 }
 
@@ -1143,13 +1108,10 @@ gpio_sim_line_config_name_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_line *line = to_gpio_sim_line(item);
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", line->name ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", line->name ?: "");
 }
 
 static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
@@ -1159,24 +1121,18 @@ static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(line->name);
 	line->name = trimmed;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1192,13 +1148,10 @@ static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
 {
 	struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", hog->name ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", hog->name ?: "");
 }
 
 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
@@ -1208,24 +1161,18 @@ static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(hog->name);
 	hog->name = trimmed;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1239,9 +1186,8 @@ static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
 	char *repr;
 	int dir;
 
-	mutex_lock(&dev->lock);
-	dir = hog->dir;
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		dir = hog->dir;
 
 	switch (dir) {
 	case GPIOD_IN:
@@ -1270,12 +1216,10 @@ gpio_sim_hog_config_direction_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 	int dir;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	if (sysfs_streq(page, "input"))
 		dir = GPIOD_IN;
@@ -1284,17 +1228,10 @@ gpio_sim_hog_config_direction_store(struct config_item *item,
 	else if (sysfs_streq(page, "output-low"))
 		dir = GPIOD_OUT_LOW;
 	else
-		dir = -EINVAL;
-
-	if (dir < 0) {
-		mutex_unlock(&dev->lock);
-		return dir;
-	}
+		return -EINVAL;
 
 	hog->dir = dir;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1312,9 +1249,8 @@ static void gpio_sim_hog_config_item_release(struct config_item *item)
 	struct gpio_sim_line *line = hog->parent;
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 
-	mutex_lock(&dev->lock);
-	line->hog = NULL;
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		line->hog = NULL;
 
 	kfree(hog->name);
 	kfree(hog);
@@ -1340,13 +1276,11 @@ gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
 	if (strcmp(name, "hog") != 0)
 		return ERR_PTR(-EINVAL);
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
 	hog = kzalloc(sizeof(*hog), GFP_KERNEL);
-	if (!hog) {
-		mutex_unlock(&dev->lock);
+	if (!hog)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_item_init_type_name(&hog->item, name,
 				   &gpio_sim_hog_config_type);
@@ -1356,8 +1290,6 @@ gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
 	hog->parent = line;
 	line->hog = hog;
 
-	mutex_unlock(&dev->lock);
-
 	return &hog->item;
 }
 
@@ -1366,9 +1298,8 @@ static void gpio_sim_line_config_group_release(struct config_item *item)
 	struct gpio_sim_line *line = to_gpio_sim_line(item);
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
 
-	mutex_lock(&dev->lock);
-	list_del(&line->siblings);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		list_del(&line->siblings);
 
 	kfree(line->name);
 	kfree(line);
@@ -1403,18 +1334,14 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
 	if (ret != 1 || nchar != strlen(name))
 		return ERR_PTR(-EINVAL);
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return ERR_PTR(-EBUSY);
-	}
 
 	line = kzalloc(sizeof(*line), GFP_KERNEL);
-	if (!line) {
-		mutex_unlock(&dev->lock);
+	if (!line)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_group_init_type_name(&line->group, name,
 				    &gpio_sim_line_config_type);
@@ -1423,8 +1350,6 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
 	line->offset = offset;
 	list_add_tail(&line->siblings, &bank->line_list);
 
-	mutex_unlock(&dev->lock);
-
 	return &line->group;
 }
 
@@ -1433,9 +1358,8 @@ static void gpio_sim_bank_config_group_release(struct config_item *item)
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 
-	mutex_lock(&dev->lock);
-	list_del(&bank->siblings);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		list_del(&bank->siblings);
 
 	kfree(bank->label);
 	kfree(bank);
@@ -1463,18 +1387,14 @@ gpio_sim_device_config_make_bank_group(struct config_group *group,
 	struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
 	struct gpio_sim_bank *bank;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return ERR_PTR(-EBUSY);
-	}
 
 	bank = kzalloc(sizeof(*bank), GFP_KERNEL);
-	if (!bank) {
-		mutex_unlock(&dev->lock);
+	if (!bank)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_group_init_type_name(&bank->group, name,
 				    &gpio_sim_bank_config_group_type);
@@ -1483,8 +1403,6 @@ gpio_sim_device_config_make_bank_group(struct config_group *group,
 	INIT_LIST_HEAD(&bank->line_list);
 	list_add_tail(&bank->siblings, &dev->bank_list);
 
-	mutex_unlock(&dev->lock);
-
 	return &bank->group;
 }
 
@@ -1492,10 +1410,10 @@ static void gpio_sim_device_config_group_release(struct config_item *item)
 {
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 
-	mutex_lock(&dev->lock);
-	if (gpio_sim_device_is_live_unlocked(dev))
-		gpio_sim_device_deactivate_unlocked(dev);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock) {
+		if (gpio_sim_device_is_live_unlocked(dev))
+			gpio_sim_device_deactivate_unlocked(dev);
+	}
 
 	mutex_destroy(&dev->lock);
 	ida_free(&gpio_sim_ida, dev->id);
@@ -1520,7 +1438,7 @@ static const struct config_item_type gpio_sim_device_config_group_type = {
 static struct config_group *
 gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 {
-	struct gpio_sim_device *dev;
+	struct gpio_sim_device *dev __free(kfree) = NULL;
 	int id;
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
@@ -1528,10 +1446,8 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 		return ERR_PTR(-ENOMEM);
 
 	id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
-	if (id < 0) {
-		kfree(dev);
+	if (id < 0)
 		return ERR_PTR(id);
-	}
 
 	config_group_init_type_name(&dev->group, name,
 				    &gpio_sim_device_config_group_type);
@@ -1542,7 +1458,7 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 	dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
 	init_completion(&dev->probe_completion);
 
-	return &dev->group;
+	return &no_free_ptr(dev)->group;
 }
 
 static struct configfs_group_operations gpio_sim_config_group_ops = {