[PATCH v8 1/5] leds: core: add generic support for RGB LED's
From: Heiner Kallweit
Date: Mon Mar 21 2016 - 13:34:36 EST
Add generic support for RGB 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.
Select LEDS_CLASS_RGB to enable building drivers using the RGB extension.
Flag LED_SET_HUE_SAT 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)
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
v2:
- move extension-specific code into a separate source file and
introduce config symbol LEDS_HSV for it
- create separate patch for the extension to sysfs
- use variable name led_cdev as in the rest if the core
- rename to_hsv to led_validate_brightness
- rename LED_BRIGHTNESS_SET_COLOR to LED_SET_HSV
- introduce helper is_off for checking whether V part
of a HSV value is zero
v3:
- change Kconfig to use depend instead of select, add help message,
and change config symbol to LEDS_COLOR
- change LED core object file name in Makefile
- rename flag LED_SET_HSV to LED_SET_COLOR
- rename is_off to led_is_off
- rename led_validate-brightness to led_confine_brightness
- rename variable in led_confine_brightness
- add dummy enum led_brightness value to enforce 32bit enum
- rename led-hsv-core.c to led-color-core.c
- move check of provided brightness value to led_confine_brightness
v4:
- change config symbol name to LEDS_RGB
- change name of new file to led-rgb-core.c
- factor out part of led_confine_brightness
- change led_is_off to __is_set_brightness
- in led_set_software_blink pass led_cdev->max_brightness instead of LED_FULL
- rename LED_SET_COLOR to LED_SET_HUE_SAT
v5:
- change "RGB Color LED" to "RGB LED" in Kconfig
- move definition of LED_HUE_SAT_MASK to drivers/leds/leds.h
- rename LED_DEV_CAP_HSV to LED_DEV_CAP_RGB
v6:
- no change
v7:
- removed "Color" from RGB Color LED in commit message and title
- don't include linux/kernel.h in led-rgb-core.c
- keep definition of LED_DEV_CAP_[] flags together
v8:
- rename LEDS_RGB to LEDS_CLASS_RGB
---
drivers/leds/Kconfig | 12 ++++++++++++
drivers/leds/Makefile | 4 +++-
drivers/leds/led-class.c | 2 +-
drivers/leds/led-core.c | 16 +++++++++-------
drivers/leds/led-rgb-core.c | 39 +++++++++++++++++++++++++++++++++++++++
drivers/leds/leds.h | 18 ++++++++++++++++++
include/linux/leds.h | 11 ++++++++++-
7 files changed, 92 insertions(+), 10 deletions(-)
create mode 100644 drivers/leds/led-rgb-core.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7f940c2..20697a2 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 "RGB LED 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
@@ -29,6 +37,10 @@ config LEDS_CLASS_FLASH
for the flash related features of a LED device. It can be built
as a module.
+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 e9d5309..7f1b2be 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 aa84e5b..007a5b3 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -53,7 +53,7 @@ static ssize_t brightness_store(struct device *dev,
if (ret)
goto unlock;
- if (state == LED_OFF)
+ if (!__is_brightness_set(state))
led_trigger_remove(led_cdev);
led_set_brightness(led_cdev, state);
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 3495d5d..e75b0c8 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -62,7 +62,7 @@ static void led_timer_function(unsigned long data)
}
brightness = led_get_brightness(led_cdev);
- if (!brightness) {
+ if (!__is_brightness_set(brightness)) {
/* Time to switch the LED on. */
brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
@@ -133,8 +133,9 @@ 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 =
+ led_confine_brightness(led_cdev,
+ led_cdev->max_brightness);
led_cdev->blink_delay_on = delay_on;
led_cdev->blink_delay_off = delay_off;
@@ -235,12 +236,13 @@ 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 (!__is_brightness_set(brightness)) {
led_cdev->flags |= LED_BLINK_DISABLE;
schedule_work(&led_cdev->set_brightness_work);
} else {
led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE;
- led_cdev->blink_brightness = brightness;
+ led_cdev->blink_brightness =
+ led_confine_brightness(led_cdev, brightness);
}
return;
}
@@ -265,7 +267,7 @@ 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 = led_confine_brightness(led_cdev, value);
if (led_cdev->flags & LED_SUSPENDED)
return;
@@ -280,7 +282,7 @@ 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);
+ led_cdev->brightness = led_confine_brightness(led_cdev, value);
if (led_cdev->flags & LED_SUSPENDED)
return 0;
diff --git a/drivers/leds/led-rgb-core.c b/drivers/leds/led-rgb-core.c
new file mode 100644
index 0000000..cbd8b35
--- /dev/null
+++ b/drivers/leds/led-rgb-core.c
@@ -0,0 +1,39 @@
+/*
+ * RGB LED Class Support
+ *
+ * Author: Heiner Kallweit <hkallweit1@xxxxxxxxx>
+ *
+ * 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"
+
+/*
+ * The color extension handles RGB LEDs but uses a HSV color model internally.
+ * led_rgb_adjust_hue_sat sets hue and saturation part of the HSV color value.
+ */
+static enum led_brightness led_rgb_adjust_hue_sat(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ /* LED_SET_HUE_SAT sets hue and saturation even if both are zero */
+ if (value & LED_SET_HUE_SAT || value > LED_FULL)
+ return value & LED_HUE_SAT_MASK;
+ else
+ return led_cdev->brightness & ~LED_BRIGHTNESS_MASK;
+}
+
+enum led_brightness led_confine_brightness(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ enum led_brightness brightness = 0;
+
+ if (led_cdev->flags & LED_DEV_CAP_RGB)
+ brightness = led_rgb_adjust_hue_sat(led_cdev, value);
+
+ return brightness |
+ min(value & LED_BRIGHTNESS_MASK, led_cdev->max_brightness);
+}
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20d..9c5f3fe 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -16,17 +16,35 @@
#include <linux/rwsem.h>
#include <linux/leds.h>
+#define LED_BRIGHTNESS_MASK 0x000000ff
+#define LED_HUE_SAT_MASK 0x00ffff00
+
static inline int led_get_brightness(struct led_classdev *led_cdev)
{
return led_cdev->brightness;
}
+static inline bool __is_brightness_set(enum led_brightness brightness)
+{
+ return (brightness & LED_BRIGHTNESS_MASK) != LED_OFF;
+}
+
void led_init_core(struct led_classdev *led_cdev);
void led_stop_software_blink(struct led_classdev *led_cdev);
void led_set_brightness_nopm(struct led_classdev *led_cdev,
enum led_brightness value);
void led_set_brightness_nosleep(struct led_classdev *led_cdev,
enum led_brightness value);
+#if IS_ENABLED(CONFIG_LEDS_CLASS_RGB)
+enum led_brightness led_confine_brightness(struct led_classdev *led_cdev,
+ enum led_brightness value);
+#else
+static inline enum led_brightness led_confine_brightness(
+ struct led_classdev *led_cdev, enum led_brightness value)
+{
+ return min(value, led_cdev->max_brightness);
+}
+#endif
extern struct rw_semaphore leds_list_lock;
extern struct list_head leds_list;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index f203a8f..58e8299 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -29,8 +29,16 @@ enum led_brightness {
LED_OFF = 0,
LED_HALF = 127,
LED_FULL = 255,
+ /*
+ * dummy enum value to make gcc use a 32 bit type for the enum
+ * even if compiled with -fshort-enums. This is needed for
+ * the enum to store hsv values.
+ */
+ LED_LEVEL_DUMMY = 0xffffffff,
};
+#define LED_SET_HUE_SAT BIT(24)
+
struct led_classdev {
const char *name;
enum led_brightness brightness;
@@ -49,7 +57,8 @@ struct led_classdev {
#define LED_BLINK_DISABLE (1 << 21)
#define LED_SYSFS_DISABLE (1 << 22)
#define LED_DEV_CAP_FLASH (1 << 23)
-#define LED_HW_PLUGGABLE (1 << 24)
+#define LED_DEV_CAP_RGB (1 << 24)
+#define LED_HW_PLUGGABLE (1 << 25)
/* Set LED brightness level
* Must not sleep. Use brightness_set_blocking for drivers
--
2.7.3