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SubjectRe: RGB support prototype
Hi!

> > > We could even export (read-only) hue/saturation for single-color LEDs...
> >
> > Related patches from Heiner Kallweit are still sitting on devel branch
> > of linux-leds.git:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds.git/log/?h=devel
> >
> > Possibly it can serve as a basis for further development.
>
> > I liked that approach because it was compatible with monochrome
> > LEDs and triggers.
>
> Yeah, I like that. I don't like the implementation and the sysfs
> interface.
>
> Let me try and see if I can turn them into something better...
>
> I'm using full 32-bits for parameters; that should give us enough
> precision. In particular, 32-bits is important for "brightness"; I
> already have light that goes from .1lm to 1000lm -- which is more than
> 8-bits can handle.
>
> lp5523 conversion... is a very quick hack.

And here's a better version. I'll still need to adjust white to be
white... but I guess that would need to be done with any solution.

I've checked, and triggers seem to work as expected (and I can select
a color for them).

Signed-off-by: Pavel Machek <pavel@ucw.cz>

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 594b24d..bad8a6e 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -19,6 +19,14 @@ config LEDS_CLASS
This option enables the led sysfs class in /sys/class/leds. You'll
need this to do anything useful with LEDs. If unsure, say N.

+config LEDS_CLASS_RGB
+ bool "LED RGB Class Support"
+ depends on LEDS_CLASS
+ help
+ This option enables support for RGB LED devices.
+ Sysfs attribute brightness is interpreted as a HSV color value.
+ For details see Documentation/leds/leds-class.txt.
+
config LEDS_CLASS_FLASH
tristate "LED Flash Class Support"
depends on LEDS_CLASS
@@ -38,6 +46,10 @@ config LEDS_BRIGHTNESS_HW_CHANGED

See Documentation/ABI/testing/sysfs-class-led for details.

+if LEDS_CLASS_RGB
+comment "RGB LED drivers"
+endif # LEDS_CLASS_RGB
+
comment "LED drivers"

config LEDS_88PM860X
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 909dae6..d5b5e76 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -1,6 +1,8 @@

# LED Core
-obj-$(CONFIG_NEW_LEDS) += led-core.o
+obj-$(CONFIG_NEW_LEDS) += led-core-objs.o
+led-core-objs-y := led-core.o
+led-core-objs-$(CONFIG_LEDS_CLASS_RGB) += led-rgb-core.o
obj-$(CONFIG_LEDS_CLASS) += led-class.o
obj-$(CONFIG_LEDS_CLASS_FLASH) += led-class-flash.o
obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index b0e2d55..0bd68a4 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -65,6 +65,83 @@ static ssize_t brightness_store(struct device *dev,
}
static DEVICE_ATTR_RW(brightness);

+static ssize_t saturation_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+ /* no lock needed for this */
+ led_update_brightness(led_cdev);
+
+ return sprintf(buf, "%u\n", led_cdev->saturation);
+}
+
+static ssize_t saturation_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ unsigned long state;
+ ssize_t ret;
+
+ mutex_lock(&led_cdev->led_access);
+
+ if (led_sysfs_is_disabled(led_cdev)) {
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ ret = kstrtoul(buf, 10, &state);
+ if (ret)
+ goto unlock;
+
+ led_cdev->saturation = state;
+
+ ret = size;
+unlock:
+ mutex_unlock(&led_cdev->led_access);
+ return ret;
+}
+static DEVICE_ATTR_RW(saturation);
+
+static ssize_t hue_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+ /* no lock needed for this */
+ led_update_brightness(led_cdev);
+
+ return sprintf(buf, "%u\n", led_cdev->hue);
+}
+
+static ssize_t hue_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ unsigned long state;
+ ssize_t ret;
+
+ mutex_lock(&led_cdev->led_access);
+
+ if (led_sysfs_is_disabled(led_cdev)) {
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ ret = kstrtoul(buf, 10, &state);
+ if (ret)
+ goto unlock;
+
+ led_cdev->hue = state;
+
+ ret = size;
+unlock:
+ mutex_unlock(&led_cdev->led_access);
+ return ret;
+}
+static DEVICE_ATTR_RW(hue);
+
+
static ssize_t max_brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -88,6 +165,8 @@ static const struct attribute_group led_trigger_group = {
static struct attribute *led_class_attrs[] = {
&dev_attr_brightness.attr,
&dev_attr_max_brightness.attr,
+ &dev_attr_hue.attr,
+ &dev_attr_saturation.attr,
NULL,
};

diff --git a/drivers/leds/led-rgb-core.c b/drivers/leds/led-rgb-core.c
new file mode 100644
index 0000000..3733032
--- /dev/null
+++ b/drivers/leds/led-rgb-core.c
@@ -0,0 +1,64 @@
+/*
+ * LED RGB Class Support
+ *
+ * Author: Heiner Kallweit <hkallweit1@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/leds.h>
+#include "leds.h"
+
+struct led_rgb led_hsv_to_rgb(struct led_hsv hsv)
+{
+ unsigned int h = hsv.hue >> 24;
+ unsigned int s = hsv.saturation >> 24;
+ unsigned int v = hsv.value >> 24;
+ unsigned int f, p, q, t, r, g, b;
+ struct led_rgb res;
+
+ if (!v) {
+ res.red = 0;
+ res.green = 0;
+ res.blue = 0;
+ return res;
+ }
+ if (!s) {
+ res.red = v << 24;
+ res.green = v << 24;
+ res.blue = v << 24;
+ return res;
+ }
+
+ 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;
+ }
+
+ printk("hsv_to: h %5d, s %5d, v %5d -> %5d, %5d, %5d\n",
+ h*390, s*390, v*390, r*390, g*390, b*390);
+
+ res.red = r << 24;
+ res.green = g << 24;
+ res.blue = b << 24;
+ return res;
+}
+EXPORT_SYMBOL_GPL(led_hsv_to_rgb);
diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
index 924e50a..3244c24 100644
--- a/drivers/leds/leds-lp5523.c
+++ b/drivers/leds/leds-lp5523.c
@@ -802,6 +802,26 @@ static ssize_t store_master_fader_leds(struct device *dev,
return ret;
}

+int lp5523_rgb_brightness(struct lp55xx_led *led, struct led_rgb r)
+{
+ struct lp55xx_chip *chip = led->chip;
+ int ret;
+
+ mutex_lock(&chip->lock);
+ r.red >>= 24;
+ r.green >>= 24;
+ r.blue >>= 24;
+ printk("RGB brightness %d %d %d\n", r.red, r.green, r.blue);
+ ret = lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr, r.red);
+ if (!ret)
+ lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr - 1, r.green);
+ if (!ret)
+ lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr - 2, r.blue);
+ mutex_unlock(&chip->lock);
+ return ret;
+
+}
+
static int lp5523_led_brightness(struct lp55xx_led *led)
{
struct lp55xx_chip *chip = led->chip;
diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
index 5377f22..16e65dc 100644
--- a/drivers/leds/leds-lp55xx-common.c
+++ b/drivers/leds/leds-lp55xx-common.c
@@ -134,6 +134,8 @@ static struct attribute *lp55xx_led_attrs[] = {
};
ATTRIBUTE_GROUPS(lp55xx_led);

+extern int lp5523_rgb_brightness(struct lp55xx_led *led, struct led_rgb r);
+
static int lp55xx_set_brightness(struct led_classdev *cdev,
enum led_brightness brightness)
{
@@ -141,6 +143,18 @@ static int lp55xx_set_brightness(struct led_classdev *cdev,
struct lp55xx_device_config *cfg = led->chip->cfg;

led->brightness = (u8)brightness;
+
+ if (led->chan_nr == 6) {
+ struct led_rgb r;
+ struct led_hsv hsv;
+
+ printk("RGB set request: %d %d %d\n", cdev->brightness, cdev->hue >> 24, cdev->saturation >> 24);
+ hsv.value = brightness << 24;
+ hsv.hue = cdev->hue;
+ hsv.saturation = cdev->saturation;
+ r = led_hsv_to_rgb(hsv);
+ return lp5523_rgb_brightness(led, r);
+ }
return cfg->brightness_fn(led);
}

@@ -176,6 +190,8 @@ static int lp55xx_init_led(struct lp55xx_led *led,
led->cdev.brightness_set_blocking = lp55xx_set_brightness;
led->cdev.groups = lp55xx_led_groups;

+ printk("Led %d name %s\n", chan, pdata->led_config[chan].name);
+
if (pdata->led_config[chan].name) {
led->cdev.name = pdata->led_config[chan].name;
} else {
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 64c56d4..bd0ae46 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -37,6 +37,8 @@ struct led_classdev {
const char *name;
enum led_brightness brightness;
enum led_brightness max_brightness;
+ int hue;
+ int saturation;
int flags;

/* Lower 16 bits reflect status */
@@ -49,6 +51,7 @@ struct led_classdev {
#define LED_HW_PLUGGABLE (1 << 19)
#define LED_PANIC_INDICATOR (1 << 20)
#define LED_BRIGHT_HW_CHANGED (1 << 21)
+#define LED_DEV_CAP_RGB (1 << 24)

/* set_brightness_work / blink_timer flags, atomic, private. */
unsigned long work_flags;
@@ -238,6 +241,26 @@ static inline bool led_sysfs_is_disabled(struct led_classdev *led_cdev)
return led_cdev->flags & LED_SYSFS_DISABLE;
}

+struct led_hsv {
+ u32 hue;
+ u32 saturation;
+ u32 value;
+};
+
+struct led_rgb {
+ u32 red;
+ u32 green;
+ u32 blue;
+};
+
+/**
+ * led_hsv_to_rgb - convert a hsv color value to rgb color model
+ * @hsv: the hsv value to convert
+ *
+ * Returns: the resulting rgb value
+ */
+struct led_rgb led_hsv_to_rgb(struct led_hsv hsv);
+
/*
* LED Triggers
*/

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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