[PATCH 1/2] leds: core: add generic support for color LED's

[Heiner Kallweit <hkallweit1@gmail.com>]

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 <hkallweit1@gmail.com>
---
 drivers/leds/led-class.c |  7 +++++--
 drivers/leds/led-core.c  | 41 ++++++++++++++++++++++++++++++++++-------
 include/linux/leds.h     |  4 ++++
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index aa84e5b..18a4558 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -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,
@@ -49,7 +52,7 @@ static ssize_t brightness_store(struct device *dev,
 		goto unlock;
 	}
 
-	ret = kstrtoul(buf, 10, &state);
+	ret = kstrtoul(buf, 0, &state);
 	if (ret)
 		goto unlock;
 
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index c29e4c9..798e31e 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -19,12 +19,32 @@
 #include <linux/rwsem.h>
 #include "leds.h"
 
+#define LED_HUE_SAT_MASK	0x00ffff00
+#define LED_BRIGHTNESS_MASK	0x000000ff
+
 DECLARE_RWSEM(leds_list_lock);
 EXPORT_SYMBOL_GPL(leds_list_lock);
 
 LIST_HEAD(leds_list);
 EXPORT_SYMBOL_GPL(leds_list);
 
+static inline enum led_brightness to_hsv(struct led_classdev *cdev,
+					 enum led_brightness value)
+{
+	enum led_brightness ret;
+
+	/*
+	 * if LED_BRIGHTNESS_SET_COLOR is set set hue and
+	 * saturation even if both are zero
+	 */
+	if (value & LED_BRIGHTNESS_SET_COLOR || value > LED_FULL)
+		ret = value & LED_HUE_SAT_MASK;
+	else
+		ret = cdev->brightness & ~LED_BRIGHTNESS_MASK;
+
+	return ret | min(value & LED_BRIGHTNESS_MASK, cdev->max_brightness);
+}
+
 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 =
+					to_hsv(led_cdev, brightness);
 			schedule_work(&led_cdev->set_brightness_work);
 		} else {
 			led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE;
-			led_cdev->blink_brightness = brightness;
+			led_cdev->blink_brightness =
+					to_hsv(led_cdev, brightness);
 		}
 		return;
 	}
@@ -265,7 +289,7 @@ EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 				enum led_brightness value)
 {
-	led_cdev->brightness = min(value, led_cdev->max_brightness);
+	led_cdev->brightness = to_hsv(led_cdev, value);
 
 	if (led_cdev->flags & LED_SUSPENDED)
 		return;
@@ -280,7 +304,10 @@ int led_set_brightness_sync(struct led_classdev *led_cdev,
 	if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 		return -EBUSY;
 
-	led_cdev->brightness = min(value, led_cdev->max_brightness);
+	if (!(led_cdev->flags & LED_DEV_CAP_COLOR))
+		value &= LED_BRIGHTNESS_MASK;
+
+	led_cdev->brightness = to_hsv(led_cdev, value);
 
 	if (led_cdev->flags & LED_SUSPENDED)
 		return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index f203a8f..8e7db72 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -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
@@ -153,6 +154,9 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
 				  unsigned long *delay_on,
 				  unsigned long *delay_off,
 				  int invert);
+
+#define LED_BRIGHTNESS_SET_COLOR	BIT(24)
+
 /**
  * led_set_brightness - set LED brightness
  * @led_cdev: the LED to set
-- 
2.7.0