drivers: led: lp5569: add charge pump configuration

The lp5569 controller contains an internal charge pump which can be useful
for driving LEDs with a forward voltage greater than the lp5569 supply.
Taking advantage of the charge pump can alleviate the need for an external
boost converter.

Add a dts property, charge-pump-mode, to the ti,lp5569 binding with which
the cp_mode bits of the MISC register will be configured.

Following the datasheet, the possible configurations are:
    0x00 -> disabled (default)
    0x01 -> 1x mode
    0x10 -> 1.5x mode
    0x11 -> auto mode

Signed-off-by: Emil Juhl <emdj@bang-olufsen.dk>

doc/releases/release-notes-4.0.rst

@@ -137,6 +137,8 @@ Drivers and Sensors
 
 * LED
 
+  * lp5569: added ``charge-pump-mode`` property to configure the charge pump of the lp5569.
+
 * LED Strip
 
 * LoRa

drivers/led/lp5569.c

@@ -30,12 +30,14 @@ LOG_MODULE_REGISTER(lp5569, CONFIG_LED_LOG_LEVEL);
 
 #define LP5569_MISC			0x2F
 #define LP5569_POWERSAVE_EN		BIT(5)
+#define LP5569_CP_MODE_SHIFT		3
 
 /* PWM base Register for controlling the duty-cycle */
 #define LP5569_LED0_PWM			0x16
 
 struct lp5569_config {
 	struct i2c_dt_spec bus;
+	const uint8_t cp_mode;
 };
 
 static int lp5569_led_set_brightness(const struct device *dev, uint32_t led,
@@ -91,7 +93,8 @@ static int lp5569_enable(const struct device *dev)
 	}
 
 	ret = i2c_reg_write_byte_dt(&config->bus, LP5569_MISC,
-				    LP5569_POWERSAVE_EN);
+				    LP5569_POWERSAVE_EN |
+				    (config->cp_mode << LP5569_CP_MODE_SHIFT));
 	if (ret < 0) {
 		LOG_ERR("LED reg update failed");
 		return ret;
@@ -156,6 +159,7 @@ static const struct led_driver_api lp5569_led_api = {
 #define LP5569_DEFINE(id)						\
 	static const struct lp5569_config lp5569_config_##id = {	\
 		.bus = I2C_DT_SPEC_INST_GET(id),			\
+		.cp_mode = DT_ENUM_IDX(DT_DRV_INST(id), charge_pump_mode),	\
 	};								\
 									\
 	PM_DEVICE_DT_INST_DEFINE(id, lp5569_pm_action);			\

dts/bindings/led/ti,lp5569.yaml

@@ -3,3 +3,18 @@ description: TI LP5569 LED
 compatible: "ti,lp5569"
 
 include: i2c-device.yaml
+
+properties:
+  charge-pump-mode:
+    type: string
+    default: "disabled"
+    enum:
+      - "disabled"
+      - "1x"
+      - "1x5"
+      - "auto"
+    description: |
+      If provided, configures the internal charge-pump mode in the MISC
+      register. This can be useful to supply a higher voltage to the LEDs, than
+      what the lp5569 is being supplied.
+      The default corresponds to the reset value of the register.