Re: [PATCH 5/6] video: add generic panel-lvds driver

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello,

On 6/2/26 6:09 AM, Johannes Schneider wrote:
> From: Thomas Haemmerle <thomas.haemmerle@leica-geosystems.com>
> 
> Barebox has no driver for "panel-lvds" compatible DT nodes, which are used by
> all i.MX8M board display pipelines to describe LVDS panels with a panel-timing
> subnode. Without this driver the VPL chain in fsl-ldb terminates before it can
> query video modes, and the LCDIF2 framebuffer driver cannot determine the active
> display resolution, so no framebuffer is allocated and no splash is shown.
> 
> The driver reads one video mode from the panel-timing subnode, enables
> an optional power-supply regulator and enable GPIO on VPL_ENABLE, and
> controls an optional backlight device.  Closely follows the Linux
> drivers/gpu/drm/panel/panel-lvds.c behavior.

We have a driver though for simple-panel. I lean towards extending the
simple-panel driver with the panel-lvds compatible and adding any
feature it might miss there.

AFAICS, there is nothing really lvds specific here. I know Linux has
separate simple-panel drivers, but the barebox simple panel driver is
different: It has no hardcoded panel types, but only parses the DT,
exactly like what you do here.

> +static int panel_lvds_enable(struct panel_lvds *panel)
> +{
> +	int ret;
> +
> +	if (panel->power) {
> +		ret = regulator_enable(panel->power);

regulator_enable(NULL) returns 0, so no need to check here.

> +	panel->enable_gpio = of_get_named_gpio_flags(dev->of_node, "enable-gpios",
> +						     0, &panel->enable_gpio_flags);

Please use the gpiod_ family of functions for new code.


Cheers,
Ahmad

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