leds: lp5562: Add multicolor brightness control

The framework for multicolor brightness control is already in place
in the lp55xx-common code but the function to control the multicolor
brightness for this particular chip is still missing.

Implement the multicolor_brightness_fn function to allow multicolor
brightness control of LEDs connected to the LP5562 LED driver.

Signed-off-by: Michal Vokáč <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/leds/leds-lp5562.c

···
 	return 0;
 }
 
+static int lp5562_multicolor_brightness(struct lp55xx_led *led)
+{
+	struct lp55xx_chip *chip = led->chip;
+	static const u8 addr[] = {
+		LP5562_REG_R_PWM,
+		LP5562_REG_G_PWM,
+		LP5562_REG_B_PWM,
+		LP5562_REG_W_PWM,
+	};
+	int ret;
+	int i;
+
+	guard(mutex)(&chip->lock);
+	for (i = 0; i < led->mc_cdev.num_colors; i++) {
+		ret = lp55xx_write(chip,
+				   addr[led->mc_cdev.subled_info[i].channel],
+				   led->mc_cdev.subled_info[i].brightness);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
 static int lp5562_led_brightness(struct lp55xx_led *led)
 {
 	struct lp55xx_chip *chip = led->chip;
···
 	.post_init_device   = lp5562_post_init_device,
 	.set_led_current    = lp5562_set_led_current,
 	.brightness_fn      = lp5562_led_brightness,
+	.multicolor_brightness_fn = lp5562_multicolor_brightness,
 	.run_engine         = lp5562_run_engine,
 	.firmware_cb        = lp55xx_firmware_loaded_cb,
 	.dev_attr_group     = &lp5562_group,