zephyr: shim: implement a generic led_get_brightness_range

Implement a generic led_get_brightness_range function using static
values from the device tree. This is currently ignoring led_id, but no
pwm_led based device is using it right now anyway, so this could cover
all existing use cases.

BRANCH=none
BUG=b:177452529
TEST=called the function, verified the values in runtime

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
Change-Id: I67dc7564eb6724e401961261ff5cc5892899ad5f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3170401
Reviewed-by: Yuval Peress <peress@google.com>
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>

5 files changed, 27 insertions, 4 deletions

diff --git a/board/volteer/led.c b/board/volteer/led.c
index 2fb9c8482c..6b09d5b4a0 100644
--- a/board/volteer/led.c
+++ b/board/volteer/led.c
@@ -42,7 +42,6 @@ struct pwm_led pwm_leds[] = {
 		.set_duty = &pwm_set_duty,
 	},
 };
-#endif
 
 void led_get_brightness_range(enum ec_led_id led_id, uint8_t *brightness_range)
 {
@@ -50,6 +49,7 @@ void led_get_brightness_range(enum ec_led_id led_id, uint8_t *brightness_range)
 	brightness_range[EC_LED_COLOR_GREEN] = 255;
 	brightness_range[EC_LED_COLOR_BLUE] = 255;
 }
+#endif
 
 int led_set_brightness(enum ec_led_id led_id, const uint8_t *brightness)
 {
diff --git a/zephyr/Kconfig.led b/zephyr/Kconfig.led
index 2274e46769..8955675d92 100644
--- a/zephyr/Kconfig.led
+++ b/zephyr/Kconfig.led
@@ -23,9 +23,9 @@ config PLATFORM_EC_LED_PWM
 	  Enable PWM (Pulse Width Modulation) controlled LEDs that conform to
 	  the Chromium OS LED behavior specification.
 
-	  Your board files must implement the led_get_brightness_range() and
-	  led_set_brightness() which are used by the LED PWM module to set the
-	  board LEDs in response to power and charging events.
+	  Your board files must implement led_set_brightness() function, which
+	  is used by the LED PWM module to set the board LEDs in response to
+	  power and charging events.
 
 if PLATFORM_EC_LED_PWM
 
diff --git a/zephyr/dts/bindings/led/cros-ec,pwm-leds.yaml b/zephyr/dts/bindings/led/cros-ec,pwm-leds.yaml
index ed0659aaac..fd99e3202a 100644
--- a/zephyr/dts/bindings/led/cros-ec,pwm-leds.yaml
+++ b/zephyr/dts/bindings/led/cros-ec,pwm-leds.yaml
@@ -66,3 +66,10 @@ properties:
   color-map-amber:
     type: array
     required: true
+
+  brightness-range:
+    type: array
+    required: true
+    description: |
+      A list of brigthness range value for all supported channels in order,
+      Red, Green, Blue, Yellow, White, Amber (0 to 255).
diff --git a/zephyr/projects/volteer/volteer/pwm_leds.dts b/zephyr/projects/volteer/volteer/pwm_leds.dts
index aa2e5bafab..659cdecbf2 100644
--- a/zephyr/projects/volteer/volteer/pwm_leds.dts
+++ b/zephyr/projects/volteer/volteer/pwm_leds.dts
@@ -26,5 +26,7 @@
 		color-map-yellow = <100  70   0>;
 		color-map-white  = <100  70 100>;
 		color-map-amber  = <100  20   0>;
+
+		brightness-range = <255 255 255 0 0 0>;
 	};
 };
diff --git a/zephyr/shim/src/pwm_led.c b/zephyr/shim/src/pwm_led.c
index 879f339b24..48565d2e56 100644
--- a/zephyr/shim/src/pwm_led.c
+++ b/zephyr/shim/src/pwm_led.c
@@ -5,6 +5,7 @@
 
 #define DT_DRV_COMPAT cros_ec_pwm_leds
 
+#include <string.h>
 #include <devicetree.h>
 
 #if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
@@ -43,4 +44,17 @@ struct pwm_led_color_map led_color_map[EC_LED_COLOR_COUNT] = {
 	[EC_LED_COLOR_AMBER]  = DT_INST_PROP(0, color_map_amber),
 };
 
+BUILD_ASSERT(DT_INST_PROP_LEN(0, brightness_range) == EC_LED_COLOR_COUNT,
+	     "brightness_range must have exactly EC_LED_COLOR_COUNT values");
+
+static const uint8_t dt_brigthness_range[EC_LED_COLOR_COUNT] = DT_INST_PROP(
+		0, brightness_range);
+
+void led_get_brightness_range(enum ec_led_id led_id, uint8_t *brightness_range)
+{
+	/* led_id is ignored, same ranges for all LEDs */
+	memcpy(brightness_range, dt_brigthness_range,
+	       sizeof(dt_brigthness_range));
+}
+
 #endif /* DT_HAS_COMPAT_STATUS_OKAY */