linux-kernel - [PATCH v8 2/6] drm/bridge: cadence: cdns-mhdp8546-core: Add mode_valid hook to drm_bridge

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Message-ID: <20251014094527.3916421-3-h-shenoy@ti.com>
Date: Tue, 14 Oct 2025 15:15:23 +0530
From: Harikrishna Shenoy <h-shenoy@...com>
To: <Laurent.pinchart@...asonboard.com>, <airlied@...il.com>,
        <andrzej.hajda@...el.com>, <andy.yan@...k-chips.com>,
        <aradhya.bhatia@...ux.dev>, <devarsht@...com>, <dianders@...omium.org>,
        <dri-devel@...ts.freedesktop.org>, <javierm@...hat.com>,
        <jernej.skrabec@...il.com>, <jonas@...boo.se>,
        <linux-kernel@...r.kernel.org>, <linux@...blig.org>,
        <luca.ceresoli@...tlin.com>, <lumag@...nel.org>, <lyude@...hat.com>,
        <maarten.lankhorst@...ux.intel.com>, <mordan@...ras.ru>,
        <mripard@...nel.org>, <neil.armstrong@...aro.org>, <rfoss@...nel.org>,
        <s-jain1@...com>, <simona@...ll.ch>, <tomi.valkeinen@...asonboard.com>,
        <tzimmermann@...e.de>, <u-kumar1@...com>
Subject: [PATCH v8 2/6] drm/bridge: cadence: cdns-mhdp8546-core: Add mode_valid hook to drm_bridge_funcs

From: Jayesh Choudhary <j-choudhary@...com>

Add cdns_mhdp_bridge_mode_valid() to check if specific mode is valid for
this bridge or not. In the legacy !(DBANC) usecase, we were using the hook
from drm_connector_helper_funcs but with DBANC we need to have mode_valid()
in drm_bridge_funcs.

Fixes: c932ced6b585 ("drm/tidss: Update encoder/bridge chain connect model")
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Signed-off-by: Jayesh Choudhary <j-choudhary@...com>
Signed-off-by: Harikrishna Shenoy <h-shenoy@...com>
---
 .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index f3076e9cdabb..7178a01e4d4d 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2162,6 +2162,25 @@ static const struct drm_edid *cdns_mhdp_bridge_edid_read(struct drm_bridge *brid
 	return cdns_mhdp_edid_read(mhdp, connector);
 }
 
+static enum drm_mode_status
+cdns_mhdp_bridge_mode_valid(struct drm_bridge *bridge,
+			    const struct drm_display_info *info,
+			    const struct drm_display_mode *mode)
+{
+	struct cdns_mhdp_device *mhdp = bridge_to_mhdp(bridge);
+
+	mutex_lock(&mhdp->link_mutex);
+
+	if (!cdns_mhdp_bandwidth_ok(mhdp, mode, mhdp->link.num_lanes,
+				    mhdp->link.rate)) {
+		mutex_unlock(&mhdp->link_mutex);
+		return MODE_CLOCK_HIGH;
+	}
+
+	mutex_unlock(&mhdp->link_mutex);
+	return MODE_OK;
+}
+
 static const struct drm_bridge_funcs cdns_mhdp_bridge_funcs = {
 	.atomic_enable = cdns_mhdp_atomic_enable,
 	.atomic_disable = cdns_mhdp_atomic_disable,
@@ -2176,6 +2195,7 @@ static const struct drm_bridge_funcs cdns_mhdp_bridge_funcs = {
 	.edid_read = cdns_mhdp_bridge_edid_read,
 	.hpd_enable = cdns_mhdp_bridge_hpd_enable,
 	.hpd_disable = cdns_mhdp_bridge_hpd_disable,
+	.mode_valid = cdns_mhdp_bridge_mode_valid,
 };
 
 static bool cdns_mhdp_detect_hpd(struct cdns_mhdp_device *mhdp, bool *hpd_pulse)
-- 
2.34.1