leds: trigger: netdev: add support for LED hw control

Add support for LED hw control for the netdev trigger.

The trigger on calling set_baseline_state to configure a new mode, will
do various check to verify if hw control can be used for the requested
mode in can_hw_control() function.

It will first check if the LED driver supports hw control for the netdev
trigger, then will use hw_control_is_supported() and finally will call
hw_control_set() to apply the requested mode.

To use such mode, interval MUST be set to the default value and net_dev
MUST be set. If one of these 2 value are not valid, hw control will
never be used and normal software fallback is used.

The default interval value is moved to a define to make sure they are
always synced.

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

diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
index cb2ec33abc4e670a7ac6608dda73c88c69da2c4a..8f592a77cbefbd965707d0f35eec659477fefcc8 100644 (file)
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -24,6 +24,8 @@
 #include <linux/timer.h>
 #include "../leds.h"
 
+#define NETDEV_LED_DEFAULT_INTERVAL    50
+
 /*
  * Configurable sysfs attributes:
  *
@@ -68,6 +70,13 @@ static void set_baseline_state(struct led_netdev_data *trigger_data)
        int current_brightness;
        struct led_classdev *led_cdev = trigger_data->led_cdev;
 
+       /* Already validated, hw control is possible with the requested mode */
+       if (trigger_data->hw_control) {
+               led_cdev->hw_control_set(led_cdev, trigger_data->mode);
+
+               return;
+       }
+
        current_brightness = led_cdev->brightness;
        if (current_brightness)
                led_cdev->blink_brightness = current_brightness;
@@ -103,12 +112,42 @@ static bool supports_hw_control(struct led_classdev *led_cdev)
 
 static bool can_hw_control(struct led_netdev_data *trigger_data)
 {
+       unsigned long default_interval = msecs_to_jiffies(NETDEV_LED_DEFAULT_INTERVAL);
+       unsigned int interval = atomic_read(&trigger_data->interval);
        struct led_classdev *led_cdev = trigger_data->led_cdev;
+       int ret;
 
        if (!supports_hw_control(led_cdev))
                return false;
 
-       return false;
+       /*
+        * Interval must be set to the default
+        * value. Any different value is rejected if in hw
+        * control.
+        */
+       if (interval != default_interval)
+               return false;
+
+       /*
+        * net_dev must be set with hw control, otherwise no
+        * blinking can be happening and there is nothing to
+        * offloaded.
+        */
+       if (!trigger_data->net_dev)
+               return false;
+
+       /* Check if the requested mode is supported */
+       ret = led_cdev->hw_control_is_supported(led_cdev, trigger_data->mode);
+       /* Fall back to software blinking if not supported */
+       if (ret == -EOPNOTSUPP)
+               return false;
+       if (ret) {
+               dev_warn(led_cdev->dev,
+                        "Current mode check failed with error %d\n", ret);
+               return false;
+       }
+
+       return true;
 }
 
 static ssize_t device_name_show(struct device *dev,
@@ -413,7 +452,7 @@ static int netdev_trig_activate(struct led_classdev *led_cdev)
        trigger_data->device_name[0] = 0;
 
        trigger_data->mode = 0;
-       atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
+       atomic_set(&trigger_data->interval, msecs_to_jiffies(NETDEV_LED_DEFAULT_INTERVAL));
        trigger_data->last_activity = 0;
 
        led_set_trigger_data(led_cdev, trigger_data);