Re: [PATCH v5 13/13] video: backlight: mt6370: Add MediaTek MT6370 support

From: AngeloGioacchino Del Regno
Date: Fri Jul 15 2022 - 08:39:00 EST

Il 15/07/22 13:26, ChiaEn Wu ha scritto:
From: ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>

MediaTek MT6370 is a SubPMIC consisting of a single cell battery charger
with ADC monitoring, RGB LEDs, dual channel flashlight, WLED backlight
driver, display bias voltage supply, one general purpose LDO, and the
USB Type-C & PD controller complies with the latest USB Type-C and PD

This adds support for MediaTek MT6370 Backlight driver. It's commonly used
to drive the display WLED. There are 4 channels inside, and each channel
supports up to 30mA of current capability with 2048 current steps in
exponential or linear mapping curves.

Signed-off-by: ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>

Hello ChiaEn,

I propose to move this one to drivers/leds (or drivers/pwm) and, instead of
registering a backlight device, register a PWM device.

This way you will be able to reuse the generic backlight-pwm driver, as you'd
be feeding the PWM device exposed by this driver to the generic one: this will
most importantly make it easy to chain it with MTK_DISP_PWM (mtk-pwm-disp)
with a devicetree that looks like...

pwmleds-disp {

compatible = "pwm-leds";

disp_led: disp-pwm {

label = "backlight-pwm";

pwms = <&pwm0 0 500000>;

max-brightness = <1024>;



backlight_lcd0: backlight {

compatible = "led-backlight";

leds = <&disp_led>, <&pmic_bl_led>;

default-brightness-level = <300>;