[PATCH] drm/bridge: imx93-mipi-dsi: Fix mode validation

[Liu Ying]

Instead of checking the last bridge's operation bit masks against
DRM_BRIDGE_OP_DETECT and DRM_BRIDGE_OP_EDID to determine if allowing
+/-0.5% pixel clock rate deviation, check any bridge after this bridge,
because the last bridge is usually a display connector bridge without
any operation bit mask when the clock rate deviation is allowed.

Fixes: ce62f8ea7e3f ("drm/bridge: imx: Add i.MX93 MIPI DSI support")
Fixes: 5849eff7f067 ("drm/bridge: imx93-mipi-dsi: use drm_bridge_chain_get_last_bridge()")
Signed-off-by: Liu Ying <victor.liu at nxp.com>
---
 drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c | 33 ++++++++++++++++-------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
index 8f312f9edf97..6d65df9ed970 100644
--- a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
@@ -493,21 +493,24 @@ static enum drm_mode_status
 imx93_dsi_validate_mode(struct imx93_dsi *dsi, const struct drm_display_mode *mode)
 {
 	struct drm_bridge *dmd_bridge = dw_mipi_dsi_get_bridge(dsi->dmd);
-	struct drm_bridge *last_bridge __free(drm_bridge_put) =
-		drm_bridge_chain_get_last_bridge(dmd_bridge->encoder);
-
-	if ((last_bridge->ops & DRM_BRIDGE_OP_DETECT) &&
-	    (last_bridge->ops & DRM_BRIDGE_OP_EDID)) {
-		unsigned long pixel_clock_rate = mode->clock * 1000;
-		unsigned long rounded_rate;
-
-		/* Allow +/-0.5% pixel clock rate deviation */
-		rounded_rate = clk_round_rate(dsi->clk_pixel, pixel_clock_rate);
-		if (rounded_rate < pixel_clock_rate * 995 / 1000 ||
-		    rounded_rate > pixel_clock_rate * 1005 / 1000) {
-			dev_dbg(dsi->dev, "failed to round clock for mode " DRM_MODE_FMT "\n",
-				DRM_MODE_ARG(mode));
-			return MODE_NOCLOCK;
+
+	drm_for_each_bridge_in_chain_from(dmd_bridge, bridge) {
+		if ((bridge->ops & DRM_BRIDGE_OP_DETECT) &&
+		    (bridge->ops & DRM_BRIDGE_OP_EDID)) {
+			unsigned long pixel_clock_rate = mode->clock * 1000;
+			unsigned long rounded_rate;
+
+			/* Allow +/-0.5% pixel clock rate deviation */
+			rounded_rate = clk_round_rate(dsi->clk_pixel, pixel_clock_rate);
+			if (rounded_rate < pixel_clock_rate * 995 / 1000 ||
+			    rounded_rate > pixel_clock_rate * 1005 / 1000) {
+				dev_dbg(dsi->dev,
+					"failed to round clock for mode " DRM_MODE_FMT "\n",
+					DRM_MODE_ARG(mode));
+				return MODE_NOCLOCK;
+			}
+
+			break;
 		}
 	}
 

---
base-commit: 877552aa875839314afad7154b5a561889e87ea9
change-id: 20260227-imx93-mipi-dsi-fix-mode-validation-425c872a2493

Best regards,
-- 
Liu Ying <victor.liu at nxp.com>