Add led_trigger_range_event() and supporting struct led_trigger_range
allowing to map a value within a value range to a color within a
color range.
Simple example would be to map a temperature with in a range to a
color between green and red.
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
drivers/leds/led-triggers.c | 42 ++++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 14 ++++++++++++++
2 files changed, 56 insertions(+)
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 3ccf88b..5cab10b 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -195,6 +195,9 @@ int led_trigger_register(struct led_trigger *trig)
struct led_classdev *led_cdev;
struct led_trigger *_trig;
+ if (trig->range && trig->range->start >= trig->range->end)
+ return -EINVAL;
+
rwlock_init(&trig->leddev_list_lock);
INIT_LIST_HEAD(&trig->led_cdevs);
@@ -294,6 +297,45 @@ void led_trigger_event(struct led_trigger *trig,
}
EXPORT_SYMBOL_GPL(led_trigger_event);
+static inline int led_trigger_interpolate(int value,
+ const struct led_trigger_range *range,
+ int x_start, int x_end)
+{
+ return x_start + DIV_ROUND_CLOSEST((value - range->start) *
+ (x_end - x_start), range->end - range->start);
+}
+
+void led_trigger_range_event(struct led_trigger *trig, int value)
+{
+ int h, s, v, hs, he, ss, se, vs, ve, hdiff;
+
+ if (!trig->range)
+ return;
+
+ hs = trig->range->color_start >> 16 & 0xff;
+ he = trig->range->color_end >> 16 & 0xff;
+ ss = trig->range->color_start >> 8 & 0xff;
+ se = trig->range->color_end >> 8 & 0xff;
+ vs = trig->range->color_start & 0xff;
+ ve = trig->range->color_end & 0xff;
+ hdiff = (252 + he - hs) % 252;
+
+ /* on color circle, choose shortest way from start to end */
+ if (hdiff <= 126 && he < hs)
+ he += 252;
+ else if (hdiff > 126 && he > hs)
+ hs += 252;
+
+ value = clamp(value, trig->range->start, trig->range->end);
+
+ h = led_trigger_interpolate(value, trig->range, hs, he) % 252;
+ s = led_trigger_interpolate(value, trig->range, ss, se);
+ v = led_trigger_interpolate(value, trig->range, vs, ve);
+
+ led_trigger_event(trig, LED_SET_HUE_SAT | h << 16 | s << 8 | v);
+}
+EXPORT_SYMBOL_GPL(led_trigger_range_event);
+
static void led_trigger_blink_setup(struct led_trigger *trig,
unsigned long *delay_on,
unsigned long *delay_off,
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 07eb074..263640e 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -241,6 +241,14 @@ enum led_brightness led_hsv_to_rgb(enum led_brightness hsv);
#define DEFINE_LED_TRIGGER(x) static struct led_trigger *x;
#define DEFINE_LED_TRIGGER_GLOBAL(x) struct led_trigger *x;
+struct led_trigger_range {
+ int start;
+ int end;
+ /* HSV color model */
+ u32 color_start;
+ u32 color_end;
+};
+
#ifdef CONFIG_LEDS_TRIGGERS
#define TRIG_NAME_MAX 50
@@ -251,6 +259,9 @@ struct led_trigger {
u8 flags;
#define LED_TRIG_CAP_RGB BIT(0)
+ /* optional element for usage with led_trigger_range_event */
+ const struct led_trigger_range *range;
+
void (*activate)(struct led_classdev *led_cdev);
void (*deactivate)(struct led_classdev *led_cdev);
@@ -278,6 +289,7 @@ extern void led_trigger_register_simple(const char *name,
extern void led_trigger_unregister_simple(struct led_trigger *trigger);
extern void led_trigger_event(struct led_trigger *trigger,
enum led_brightness event);
+extern void led_trigger_range_event(struct led_trigger *trigger, int value);
extern void led_trigger_blink(struct led_trigger *trigger,
unsigned long *delay_on,
unsigned long *delay_off);
@@ -324,6 +336,8 @@ static inline void led_trigger_register_simple(const char *name,
static inline void led_trigger_unregister_simple(struct led_trigger *trigger) {}
static inline void led_trigger_event(struct led_trigger *trigger,
enum led_brightness event) {}
+static inline void led_trigger_range_event(struct led_trigger *trigger,
+ int value) {}
static inline void led_trigger_blink(struct led_trigger *trigger,
unsigned long *delay_on,
unsigned long *delay_off) {}
--
2.7.2
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