Re: [PATCH v3 2/2] drm/panel: Add driver for Raydium RM69220 DDIC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The panel reset GPIO is initialized to a de-asserted state during probe, violating power sequencing and potentially back-powering the display controller.
- [Medium] The backlight update status function permanently clears the `MIPI_DSI_MODE_LPM` flag on error.
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commit ff679a020d6cdcdc5214b83056b055c35077760d
Author: Alexander Koskovich <akoskovich@pm.me>

drm/panel: Add driver for Raydium RM69220 DDIC

This patch adds a new DRM panel driver for the Raydium RM69220 display driver
IC, primarily supporting the BOE BF068MWM-TD0 panel.

> diff --git a/drivers/gpu/drm/panel/panel-raydium-rm69220.c b/drivers/gpu/drm/panel/panel-raydium-rm69220.c
> new file mode 100644
> index 0000000000000..4fa3036c4b5fb
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-raydium-rm69220.c
[ ... ]
> +static int raydium_rm69220_bl_update_status(struct backlight_device *bl)
> +{
> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
> +	if (ret < 0)
> +		return ret;

[Severity: Medium]
If mipi_dsi_dcs_set_display_brightness_large() fails here, does this return
path leave MIPI_DSI_MODE_LPM permanently cleared? It seems this might cause
all subsequent DSI commands to be sent in High Speed mode.

> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	return 0;
> +}
[ ... ]
> +static int raydium_rm69220_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct raydium_rm69220 *ctx;
> +	int ret;
[ ... ]
> +	ret = devm_regulator_bulk_get_const(dev,
> +					    ARRAY_SIZE(raydium_rm69220_supplies),
> +					    raydium_rm69220_supplies,
> +					    &ctx->supplies);
> +	if (ret < 0)
> +		return ret;
> +
> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);

[Severity: High]
Does initializing the reset GPIO to GPIOD_OUT_LOW (logically de-asserted)
during probe risk back-powering the display controller? Since the panel's
power regulators are not enabled yet, could this drive current through the
internal ESD diodes into the unpowered rails?

> +	if (IS_ERR(ctx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +				     "Failed to get reset-gpios\n");
> +
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260704-asteroids-panel-support-v3-0-38dc92570579@pm.me?part=2