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-rw-r--r--drivers/gpio/gpiolib.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 51a8d4103be..aef6b3d8e2c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -505,6 +505,51 @@ static int match_export(struct device *dev, void *data)
}
/**
+ * gpio_export_link - create a sysfs link to an exported GPIO node
+ * @dev: device under which to create symlink
+ * @name: name of the symlink
+ * @gpio: gpio to create symlink to, already exported
+ *
+ * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
+ * node. Caller is responsible for unlinking.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
+{
+ struct gpio_desc *desc;
+ int status = -EINVAL;
+
+ if (!gpio_is_valid(gpio))
+ goto done;
+
+ mutex_lock(&sysfs_lock);
+
+ desc = &gpio_desc[gpio];
+
+ if (test_bit(FLAG_EXPORT, &desc->flags)) {
+ struct device *tdev;
+
+ tdev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (tdev != NULL) {
+ status = sysfs_create_link(&dev->kobj, &tdev->kobj,
+ name);
+ } else {
+ status = -ENODEV;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_export_link);
+
+/**
* gpio_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable
*