leds: core: add generic support for color LED's

Add generic support for color LED's.

Basic idea is to use enum led_brightness also for the hue and saturation color components.This allows to implement the color extension w/o changes to struct led_classdev.

Flag LED_BRIGHTNESS_SET_COLOR BIT(24) allows to specify that hue / saturation should be overridden even if the provided values are zero.

Some examples for writing values to /sys/class/leds/<xx>/brightness:
(now also hex notation can be used)

255 -> set full brightness and keep existing color if set
0 -> switch LED off but keep existing color so that it can be restored
if the LED is switched on again later
0x1000000 -> switch LED off and set also hue and saturation to 0

0x00ffff -> set full brightness, full saturation and set hue to 0 (red)

Setting delayed_set_value in case of LED_BLINK_DISABLE was moved to allow using the color information if provided by the caller of led_set_brightness.

Signed-off-by Heiner Kallweit <[email protected]>

---
  drivers/leds/led-class.c |  7 +++++--
  drivers/leds/led-core.c  | 41 ++++++++++++++++++++++++++++++++++-------
  include/linux/leds.h     |  4 ++++
  3 files changed, 43 insertions(+), 9 deletions(-)

drivers/leds/led-class.c +4 -1

index aa84e5b..18a4558 100644
@@ -32,7 +32,10 @@ static ssize_t brightness_show(struct device *dev,
  	/* no lock needed for this */
  	led_update_brightness(led_cdev);
 
-	return sprintf(buf, "%u\n", led_cdev->brightness);
+	if (led_cdev->brightness > LED_FULL)
+		return sprintf(buf, "%#06x\n", led_cdev->brightness);
+	else
+		return sprintf(buf, "%u\n", led_cdev->brightness);
  }
 
  static ssize_t brightness_store(struct device *dev,

drivers/leds/led-class.c +0 -0

  	if (ret)
  		goto unlock;
 

drivers/leds/led-core.c +0 -0

index c29e4c9..798e31e 100644
@@ -19,12 +19,32 @@
  #include <linux/rwsem.h>
  #include "leds.h"
 

drivers/leds/led-core.c +6 -0

+					 enum led_brightness value)
+{
+	enum led_brightness ret;
+
+	/*
+	 * if LED_BRIGHTNESS_SET_COLOR is set set hue and

drivers/leds/led-core.c +6 -4

  static int led_set_output(struct led_classdev *cdev,
  			  enum led_brightness value)
  {

@@ -62,7 +82,7 @@ static void led_timer_function(unsigned long data)
  	}
 
  	brightness = led_get_brightness(led_cdev);
-	if (!brightness) {
+	if (!(brightness & LED_BRIGHTNESS_MASK)) {
  		/* Time to switch the LED on. */
  		brightness = led_cdev->blink_brightness;
  		delay = led_cdev->blink_delay_on;

@@ -106,7 +126,6 @@ static void set_brightness_delayed(struct work_struct *ws)
  	int ret = 0;
 
  	if (led_cdev->flags & LED_BLINK_DISABLE) {
-		led_cdev->delayed_set_value = LED_OFF;
  		led_stop_software_blink(led_cdev);
  		led_cdev->flags &= ~LED_BLINK_DISABLE;
  	}

@@ -133,7 +152,7 @@ static void led_set_software_blink(struct led_classdev *led_cdev,
  	if (current_brightness)
  		led_cdev->blink_brightness = current_brightness;
  	if (!led_cdev->blink_brightness)
-		led_cdev->blink_brightness = led_cdev->max_brightness;
+		led_cdev->blink_brightness = to_hsv(led_cdev, LED_FULL);
 
  	led_cdev->blink_delay_on = delay_on;
  	led_cdev->blink_delay_off = delay_off;

@@ -225,6 +244,8 @@ EXPORT_SYMBOL_GPL(led_stop_software_blink);
  void led_set_brightness(struct led_classdev *led_cdev,
  			enum led_brightness brightness)
  {
+	if (!(led_cdev->flags & LED_DEV_CAP_COLOR))
+		brightness &= LED_BRIGHTNESS_MASK;
  	/*
  	 * In case blinking is on delay brightness setting
  	 * until the next timer tick.

@@ -235,12 +256,15 @@ void led_set_brightness(struct led_classdev *led_cdev,
  		 * work queue task to avoid problems in case we are called
  		 * from hard irq context.
  		 */
-		if (brightness == LED_OFF) {
+		if ((brightness & LED_BRIGHTNESS_MASK) == LED_OFF) {
  			led_cdev->flags |= LED_BLINK_DISABLE;
+			led_cdev->delayed_set_value =

drivers/leds/led-core.c +0 -0

  	if (led_cdev->flags & LED_SUSPENDED)
  		return 0;

include/linux/leds.h +1 -0

index f203a8f..8e7db72 100644
@@ -50,6 +50,7 @@ struct led_classdev {
  #define LED_SYSFS_DISABLE	(1 << 22)
  #define LED_DEV_CAP_FLASH	(1 << 23)
  #define LED_HW_PLUGGABLE	(1 << 24)
+#define LED_DEV_CAP_COLOR	(1 << 25)
 
  	/* Set LED brightness level
  	 * Must not sleep. Use brightness_set_blocking for drivers

include/linux/leds.h +0 -0

  /**
   * led_set_brightness - set LED brightness
   * @led_cdev: the LED to set