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

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 <redacted>
---
 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