leds: add API to get attached device for LED hw control

Some specific LED triggers blink the LED based on events from a device
or subsystem.
For example, an LED could be blinked to indicate a network device is
receiving packets, or a disk is reading blocks. To correctly enable and
request the hw control of the LED, the trigger has to check if the
network interface or block device configured via a /sys/class/led file
match the one the LED driver provide for hw control for.

Provide an API call to get the device which the LED blinks for.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/leds.h b/include/linux/leds.h
index 4caf559b1922cca2ea88826d30f8901cbebbb7f4..3268b4e789d627793034dfbdf80e9406562b31aa 100644 (file)
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -220,6 +220,12 @@ struct led_classdev {
         */
        int                     (*hw_control_get)(struct led_classdev *led_cdev,
                                                  unsigned long *flags);
+       /*
+        * Get the device this LED blinks in response to.
+        * e.g. for a PHY LED, it is the network device. If the LED is
+        * not yet associated to a device, return NULL.
+        */
+       struct device           *(*hw_control_get_device)(struct led_classdev *led_cdev);
 #endif
 
 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED