Re: [PATCH 3/3] drm/panel: himax-hx83121a: add backlight regulator support

[Pengyu Luo]

On Tue, 09 Jun 2026 00:26:22 +0800, Icenowy Zheng <zhengxingda@xxxxxxxxxxx> wrote:
> diff --git a/drivers/gpu/drm/panel/panel-himax-hx83121a.c b/drivers/gpu/drm/panel/panel-himax-hx83121a.c
> index 1a7e0125bced..e31e2fba0a78 100644
> --- a/drivers/gpu/drm/panel/panel-himax-hx83121a.c
> +++ b/drivers/gpu/drm/panel/panel-himax-hx83121a.c
> @@ -195,7 +197,27 @@ static int himax_bl_update_status(struct backlight_device *bl)
> [ ... skip 18 lines ... ]
> +		ret = regulator_enable(ctx->bl_supply);
> +	if (ret)
> +		return ret;
> +
> +	ctx->backlight_enabled = true;
> +

If you use a pin, (it is indeed a hwen pin as we know) you can
simplify it like this,

bool bl_enable_now = !!brightness;

if (ctx->bl_enable != bl_enable_now) {
	gpiod_set_value(ctx->hwen_gpio, bl_enable_now);
	ctx->bl_enable = bl_enable_now;
}

BTW, iirc, panel bias can be turned off too, although I don't think
this will save too much power.

Best wishes,
Pengyu

-- 
Best wishes,
Pengyu