Re: [PATCH v10 2/3] drm/bridge: imx: Add i.MX93 parallel display format configuration support

[Liu Ying <victor.liu@nxp.com>]

On Mon, Mar 02, 2026 at 05:10:41PM +0100, Marco Felsch wrote:
> From: Liu Ying <victor.liu@nxp.com>
> 
> NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
> configures parallel display format by using the "PARALLEL_DISP_FORMAT"
> field. Add a DRM bridge driver to support the display format configuration.
> 
> Signed-off-by: Liu Ying <victor.liu@nxp.com>
> [m.felsch@pengutronix.de: port to v7.0-rc1]
> [m.felsch@pengutronix.de: add review feedback (Alexander)]
> [m.felsch@pengutronix.de: fix to short Kconfig description (checkpath)]
> [m.felsch@pengutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
> [m.felsch@pengutronix.de: add bus-width support]
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
>  drivers/gpu/drm/bridge/imx/Kconfig      |  11 ++
>  drivers/gpu/drm/bridge/imx/Makefile     |   1 +
>  drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 225 ++++++++++++++++++++++++++++++++
>  3 files changed, 237 insertions(+)
> 

[...]

> +static bool imx93_pdfc_bus_output_fmt_supported(const  u32 fmt)

As I mentioned in v9, can you drop const?
I don't think const is needed.

> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(imx93_pdfc_bus_output_fmts); i++) {
> +		if (imx93_pdfc_bus_output_fmts[i] == fmt)
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
> +static u32 *
> +imx93_pdfc_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> +					    struct drm_bridge_state *bridge_state,
> +					    struct drm_crtc_state *crtc_state,
> +					    struct drm_connector_state *conn_state,
> +					    u32 output_fmt,
> +					    unsigned int *num_input_fmts)
> +{
> +	struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
> +	u32 *input_fmts;
> +
> +	*num_input_fmts = 0;
> +
> +	input_fmts = kmalloc_obj(*input_fmts, GFP_KERNEL);

With the below two commits in v7.0-rc1, I believe that GFP_KERNEL can be
dropped.

bf4afc53b77a Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
e19e1b480ac7 add default_gfp() helper macro and use it in the new *alloc_obj() helpers


> +	if (!input_fmts)
> +		return NULL;
> +
> +	*num_input_fmts = 1;
> +
> +	if (!imx93_pdfc_bus_output_fmt_supported(output_fmt)) {
> +		dev_dbg(pdfc->dev, "No valid output bus-fmt detected, fallback to MEDIA_BUS_FMT_RGB888_1X24\n");
> +		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +		return input_fmts;
> +	}
> +
> +	switch (output_fmt) {
> +	case MEDIA_BUS_FMT_RGB888_1X24:
> +	case MEDIA_BUS_FMT_RGB565_1X16:
> +		input_fmts[0] = output_fmt;
> +		break;
> +	case MEDIA_BUS_FMT_RGB666_1X18:
> +	case MEDIA_BUS_FMT_FIXED:
> +		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +		break;
> +	}
> +
> +	return input_fmts;
> +}
> +
> +static int imx93_pdfc_bridge_atomic_check(struct drm_bridge *bridge,
> +					  struct drm_bridge_state *bridge_state,
> +					  struct drm_crtc_state *crtc_state,
> +					  struct drm_connector_state *conn_state)
> +{
> +	struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
> +	const u32 format = bridge_state->output_bus_cfg.format;

Can you drop const?

-- 
Regards,
Liu Ying