drm: renesas: rz-du: mipi_dsi: Add feature flag for 16BPP support

Introduce the `RZ_MIPI_DSI_FEATURE_16BPP` flag in `rzg2l_mipi_dsi_hw_info`
to indicate support for 16BPP pixel formats. The RZ/V2H(P) SoC supports
16BPP, whereas this feature is missing on the RZ/G2L SoC.

Update the `mipi_dsi_host_attach()` function to check this flag before
allowing 16BPP formats. If the SoC does not support 16BPP, return an error
to prevent incorrect format selection.

This change enables finer-grained format support control for different
SoC variants.

Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20250609225630.502888-8-prabhakar.mahadev-lad.rj@bp.renesas.com

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
index 004911240cefd25af33bf50d7630596657f2a22a..afb427e678bd7106f87757093995972d455e341e 100644 (file)
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -34,6 +34,8 @@
 
 #define RZG2L_DCS_BUF_SIZE     128 /* Maximum DCS buffer size in external memory. */
 
+#define RZ_MIPI_DSI_FEATURE_16BPP      BIT(0)
+
 struct rzg2l_mipi_dsi;
 
 struct rzg2l_mipi_dsi_hw_info {
@@ -43,6 +45,7 @@ struct rzg2l_mipi_dsi_hw_info {
        u32 link_reg_offset;
        unsigned long min_dclk;
        unsigned long max_dclk;
+       u8 features;
 };
 
 struct rzg2l_mipi_dsi {
@@ -672,8 +675,16 @@ static int rzg2l_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 
        switch (mipi_dsi_pixel_format_to_bpp(device->format)) {
        case 24:
+               break;
        case 18:
                break;
+       case 16:
+               if (!(dsi->info->features & RZ_MIPI_DSI_FEATURE_16BPP)) {
+                       dev_err(dsi->dev, "Unsupported format 0x%04x\n",
+                               device->format);
+                       return -EINVAL;
+               }
+               break;
        default:
                dev_err(dsi->dev, "Unsupported format 0x%04x\n", device->format);
                return -EINVAL;