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gpio: sysfs: allow disabling the legacy parts of the GPIO sysfs interface
Add a Kconfig switch allowing to disable the legacy parts of the GPIO sysfs interface. This means that even though we keep the /sys/class/gpio/ directory, it no longer contains the global export/unexport attribute pair (instead, the user should use the per-chip export/unpexport) nor the gpiochip$BASE entries. This option default to y if GPIO sysfs is enabled but we'll default it to n at some point in the future. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20250704-gpio-sysfs-chip-export-v4-9-9289d8758243@linaro.org Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski
parent
4fa93223e0
commit
e69c6db4cd
2 changed files with 50 additions and 0 deletions
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@ -69,6 +69,14 @@ config GPIO_SYSFS
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use the character device /dev/gpiochipN with the appropriate
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ioctl() operations instead.
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config GPIO_SYSFS_LEGACY
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bool "Enable legacy functionalities of the sysfs interface"
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depends on GPIO_SYSFS
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default y if GPIO_SYSFS
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help
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Say Y here if you want to enable the legacy, global GPIO
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numberspace-based functionalities of the sysfs interface.
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config GPIO_CDEV
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bool "Character device (/dev/gpiochipN) support" if EXPERT
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default y
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@ -24,6 +24,8 @@
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#include "gpiolib.h"
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#include "gpiolib-sysfs.h"
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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struct kernfs_node;
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#define GPIO_IRQF_TRIGGER_NONE 0
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@ -41,6 +43,8 @@ enum {
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GPIO_SYSFS_LINE_CLASS_ATTR_SIZE,
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};
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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enum {
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GPIO_SYSFS_LINE_CHIP_ATTR_DIRECTION = 0,
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GPIO_SYSFS_LINE_CHIP_ATTR_VALUE,
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@ -55,21 +59,26 @@ struct gpiod_data {
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struct device *dev;
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struct mutex mutex;
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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struct kernfs_node *value_kn;
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int irq;
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unsigned char irq_flags;
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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bool direction_can_change;
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struct kobject *parent;
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struct device_attribute dir_attr;
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struct device_attribute val_attr;
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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struct device_attribute edge_attr;
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struct device_attribute active_low_attr;
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struct attribute *class_attrs[GPIO_SYSFS_LINE_CLASS_ATTR_SIZE];
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struct attribute_group class_attr_group;
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const struct attribute_group *class_attr_groups[2];
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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struct attribute *chip_attrs[GPIO_SYSFS_LINE_CHIP_ATTR_SIZE];
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struct attribute_group chip_attr_group;
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@ -80,7 +89,9 @@ struct gpiodev_data {
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struct list_head exported_lines;
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struct gpio_device *gdev;
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struct device *cdev_id; /* Class device by GPIO device ID */
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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struct device *cdev_base; /* Class device by GPIO base */
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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};
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/*
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@ -188,6 +199,7 @@ static ssize_t value_store(struct device *dev, struct device_attribute *attr,
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return size;
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}
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
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{
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struct gpiod_data *data = priv;
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@ -383,6 +395,7 @@ static ssize_t active_low_store(struct device *dev,
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return gpio_sysfs_set_active_low(data, value) ?: size;
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}
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
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int n)
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@ -397,6 +410,7 @@ static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
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if (!data->direction_can_change)
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mode = 0;
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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} else if (strcmp(attr->name, "edge") == 0) {
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data = container_of(dev_attr, struct gpiod_data, edge_attr);
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@ -406,6 +420,7 @@ static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
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if (!data->direction_can_change &&
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test_bit(FLAG_IS_OUT, &data->desc->flags))
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mode = 0;
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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}
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return mode;
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@ -426,6 +441,7 @@ static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
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* /ngpio ... matching gpio_chip.ngpio
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*/
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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static ssize_t base_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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@ -434,6 +450,7 @@ static ssize_t base_show(struct device *dev, struct device_attribute *attr,
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return sysfs_emit(buf, "%u\n", data->gdev->base);
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}
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static DEVICE_ATTR_RO(base);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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static ssize_t label_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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@ -558,6 +575,7 @@ static struct device_attribute dev_attr_unexport = __ATTR(unexport, 0200,
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NULL,
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chip_unexport_store);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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static struct attribute *gpiochip_attrs[] = {
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&dev_attr_base.attr,
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&dev_attr_label.attr,
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@ -565,6 +583,7 @@ static struct attribute *gpiochip_attrs[] = {
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NULL,
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};
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ATTRIBUTE_GROUPS(gpiochip);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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static struct attribute *gpiochip_ext_attrs[] = {
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&dev_attr_label.attr,
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@ -575,6 +594,7 @@ static struct attribute *gpiochip_ext_attrs[] = {
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};
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ATTRIBUTE_GROUPS(gpiochip_ext);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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/*
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* /sys/class/gpio/export ... write-only
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* integer N ... number of GPIO to export (full access)
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@ -639,10 +659,13 @@ static struct attribute *gpio_class_attrs[] = {
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NULL,
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};
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ATTRIBUTE_GROUPS(gpio_class);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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static const struct class gpio_class = {
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.name = "gpio",
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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.class_groups = gpio_class_groups,
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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};
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static int match_gdev(struct device *dev, const void *desc)
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@ -754,6 +777,8 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
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gpiod_attr_init(&desc_data->dir_attr, "direction",
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direction_show, direction_store);
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gpiod_attr_init(&desc_data->val_attr, "value", value_show, value_store);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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gpiod_attr_init(&desc_data->edge_attr, "edge", edge_show, edge_store);
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gpiod_attr_init(&desc_data->active_low_attr, "active_low",
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active_low_show, active_low_store);
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@ -789,6 +814,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
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status = -ENODEV;
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goto err_unregister_device;
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}
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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gdev_data = gdev_get_data(gdev);
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if (!gdev_data) {
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@ -832,10 +858,12 @@ err_remove_groups:
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err_free_name:
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kfree(desc_data->chip_attr_group.name);
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err_put_dirent:
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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sysfs_put(desc_data->value_kn);
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err_unregister_device:
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device_unregister(desc_data->dev);
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err_free_data:
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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kfree(desc_data);
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err_clear_bit:
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clear_bit(FLAG_EXPORT, &desc->flags);
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@ -844,12 +872,14 @@ err_clear_bit:
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}
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EXPORT_SYMBOL_GPL(gpiod_export);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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static int match_export(struct device *dev, const void *desc)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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return gpiod_is_equal(data->desc, desc);
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}
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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/**
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* gpiod_export_link - create a sysfs link to an exported GPIO node
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@ -866,6 +896,7 @@ static int match_export(struct device *dev, const void *desc)
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int gpiod_export_link(struct device *dev, const char *name,
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struct gpio_desc *desc)
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{
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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struct device *cdev;
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int ret;
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@ -882,6 +913,9 @@ int gpiod_export_link(struct device *dev, const char *name,
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put_device(cdev);
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return ret;
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#else
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return -EOPNOTSUPP;
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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}
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EXPORT_SYMBOL_GPL(gpiod_export_link);
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@ -920,6 +954,7 @@ void gpiod_unexport(struct gpio_desc *desc)
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list_del(&desc_data->list);
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clear_bit(FLAG_EXPORT, &desc->flags);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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sysfs_put(desc_data->value_kn);
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device_unregister(desc_data->dev);
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@ -929,6 +964,7 @@ void gpiod_unexport(struct gpio_desc *desc)
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*/
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if (desc_data->irq_flags)
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gpio_sysfs_free_irq(desc_data);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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sysfs_remove_groups(desc_data->parent,
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desc_data->chip_attr_groups);
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@ -979,6 +1015,7 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
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guard(mutex)(&sysfs_lock);
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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/* use chip->base for the ID; it's already known to be unique */
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data->cdev_base = device_create_with_groups(&gpio_class, parent,
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MKDEV(0, 0), data,
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@ -990,13 +1027,16 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
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kfree(data);
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return err;
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}
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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data->cdev_id = device_create_with_groups(&gpio_class, parent,
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MKDEV(0, 0), data,
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gpiochip_ext_groups,
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"chip%d", gdev->id);
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if (IS_ERR(data->cdev_id)) {
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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device_unregister(data->cdev_base);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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err = PTR_ERR(data->cdev_id);
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kfree(data);
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return err;
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@ -1016,7 +1056,9 @@ void gpiochip_sysfs_unregister(struct gpio_device *gdev)
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if (!data)
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return;
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#if IS_ENABLED(CONFIG_GPIO_SYSFS_LEGACY)
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device_unregister(data->cdev_base);
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#endif /* CONFIG_GPIO_SYSFS_LEGACY */
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device_unregister(data->cdev_id);
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kfree(data);
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}
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