Add support for RGB LED's. Flag LED_DEV_CAP_RGB is used to instruct
the core to convert HSV to RGB on output.
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
v2:
- move hsv -> rgb conversion to separate file
- remove flag LED_DEV_CAP_RGB
---
drivers/leds/led-core.c | 15 ++++++++++++++-
drivers/leds/led-hsv-core.c | 35 +++++++++++++++++++++++++++++++++++
drivers/leds/leds.h | 1 +
3 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 64b627a..13a9d1e 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -31,6 +31,10 @@ static int __led_set_brightness(struct led_classdev *led_cdev,
if (!led_cdev->brightness_set)
return -ENOTSUPP;
+#if IS_ENABLED(CONFIG_LEDS_HSV)
+ value = led_hsv_to_rgb(value);
+#endif
+
led_cdev->brightness_set(led_cdev, value);
return 0;
@@ -42,6 +46,10 @@ static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
if (!led_cdev->brightness_set_blocking)
return -ENOTSUPP;
+#if IS_ENABLED(CONFIG_LEDS_HSV)
+ value = led_hsv_to_rgb(value);
+#endif
+
return led_cdev->brightness_set_blocking(led_cdev, value);
}
@@ -296,7 +304,12 @@ int led_update_brightness(struct led_classdev *led_cdev)
{
int ret = 0;
- if (led_cdev->brightness_get) {
+ /*
+ * for now reading back the color is not supported as multiple
+ * HSV -> RGB -> HSV conversions may distort the color due to
+ * rounding issues in the conversion algorithm
+ */
+ if (led_cdev->brightness_get && !(led_cdev->flags & LED_DEV_CAP_HSV)) {
ret = led_cdev->brightness_get(led_cdev);
if (ret >= 0) {
led_cdev->brightness = ret;
diff --git a/drivers/leds/led-hsv-core.c b/drivers/leds/led-hsv-core.c
index 3c31139..7d43f73 100644
--- a/drivers/leds/led-hsv-core.c
+++ b/drivers/leds/led-hsv-core.c
@@ -28,3 +28,38 @@ enum led_brightness led_validate_brightness(struct led_classdev *led_cdev,
return ret | min(value & LED_BRIGHTNESS_MASK, led_cdev->max_brightness);
}
+
+enum led_brightness led_hsv_to_rgb(enum led_brightness hsv)
+{
+ int h = min_t(int, (hsv >> 16) & 0xff, 251);
+ int s = (hsv >> 8) & 0xff;
+ int v = hsv & 0xff;
+ int f, p, q, t, r, g, b;
+
+ if (!v)
+ return 0;
+ if (!s)
+ return (v << 16) + (v << 8) + v;
+
+ f = DIV_ROUND_CLOSEST((h % 42) * 255, 42);
+ p = v - DIV_ROUND_CLOSEST(s * v, 255);
+ q = v - DIV_ROUND_CLOSEST(f * s * v, 255 * 255);
+ t = v - DIV_ROUND_CLOSEST((255 - f) * s * v, 255 * 255);
+
+ switch (h / 42) {
+ case 0:
+ r = v; g = t; b = p; break;
+ case 1:
+ r = q; g = v; b = p; break;
+ case 2:
+ r = p; g = v; b = t; break;
+ case 3:
+ r = p; g = q; b = v; break;
+ case 4:
+ r = t; g = p; b = v; break;
+ case 5:
+ r = v; g = p; b = q; break;
+ }
+
+ return (r << 16) + (g << 8) + b;
+}
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index ac3f1be..3f35675 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -37,6 +37,7 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,
#if IS_ENABLED(CONFIG_LEDS_HSV)
enum led_brightness led_validate_brightness(struct led_classdev *led_cdev,
enum led_brightness value);
+enum led_brightness led_hsv_to_rgb(enum led_brightness hsv);
#else
static inline enum led_brightness led_validate_brightness(
struct led_classdev *led_cdev, enum led_brightness value)
--
2.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-leds" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
