From: Rahul T R <r-raviku...@ti.com>

In J721S2 EVMs DP0 hpd is not connected to correct
hpd pin on SOC, to handle such cases, Add support for
"no-hpd" property in the device tree node to disable
hpd

Also change the log level for dpcd read failuers to
debug, since framework retries 32 times for each read

Signed-off-by: Rahul T R <r-raviku...@ti.com>
Signed-off-by: Jayesh Choudhary <j-choudh...@ti.com>
---
 .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 37 ++++++++++++++++---
 .../drm/bridge/cadence/cdns-mhdp8546-core.h   |  1 +
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c 
b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index f6822dfa3805..e177794b069d 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -54,6 +54,8 @@
 #include "cdns-mhdp8546-hdcp.h"
 #include "cdns-mhdp8546-j721e.h"
 
+static int cdns_mhdp_update_link_status(struct cdns_mhdp_device *mhdp);
+
 static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp)
 {
        int ret, empty;
@@ -749,7 +751,7 @@ static int cdns_mhdp_fw_activate(const struct firmware *fw,
         * MHDP_HW_STOPPED happens only due to driver removal when
         * bridge should already be detached.
         */
-       if (mhdp->bridge_attached)
+       if (mhdp->bridge_attached && !mhdp->no_hpd)
                writel(~(u32)CDNS_APB_INT_MASK_SW_EVENT_INT,
                       mhdp->regs + CDNS_APB_INT_MASK);
 
@@ -845,7 +847,7 @@ static ssize_t cdns_mhdp_transfer(struct drm_dp_aux *aux,
                ret = cdns_mhdp_dpcd_read(mhdp, msg->address,
                                          msg->buffer, msg->size);
                if (ret) {
-                       dev_err(mhdp->dev,
+                       dev_dbg(mhdp->dev,
                                "Failed to read DPCD addr %u\n",
                                msg->address);
 
@@ -1738,6 +1740,19 @@ static int cdns_mhdp_attach(struct drm_bridge *bridge,
 
        spin_unlock(&mhdp->start_lock);
 
+       if (mhdp->no_hpd) {
+               ret = wait_event_timeout(mhdp->fw_load_wq,
+                                        mhdp->hw_state == MHDP_HW_READY,
+                                        msecs_to_jiffies(100));
+               if (ret == 0) {
+                       dev_err(mhdp->dev, "%s: Timeout waiting for fw 
loading\n",
+                               __func__);
+                       return -ETIMEDOUT;
+               }
+
+               cdns_mhdp_update_link_status(mhdp);
+               return 0;
+       }
        /* Enable SW event interrupts */
        if (hw_ready)
                writel(~(u32)CDNS_APB_INT_MASK_SW_EVENT_INT,
@@ -2256,7 +2271,16 @@ static int cdns_mhdp_update_link_status(struct 
cdns_mhdp_device *mhdp)
 
        mutex_lock(&mhdp->link_mutex);
 
-       mhdp->plugged = cdns_mhdp_detect_hpd(mhdp, &hpd_pulse);
+       if (mhdp->no_hpd) {
+               ret = drm_dp_dpcd_read_link_status(&mhdp->aux, status);
+               hpd_pulse = false;
+               if (ret < 0)
+                       mhdp->plugged = false;
+               else
+                       mhdp->plugged = true;
+       } else {
+               mhdp->plugged = cdns_mhdp_detect_hpd(mhdp, &hpd_pulse);
+       }
 
        if (!mhdp->plugged) {
                cdns_mhdp_link_down(mhdp);
@@ -2451,6 +2475,8 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
        mhdp->aux.dev = dev;
        mhdp->aux.transfer = cdns_mhdp_transfer;
 
+       mhdp->no_hpd = of_property_read_bool(dev->of_node, "cdns,no-hpd");
+
        mhdp->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(mhdp->regs)) {
                dev_err(dev, "Failed to get memory resource\n");
@@ -2526,8 +2552,9 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 
        mhdp->bridge.of_node = pdev->dev.of_node;
        mhdp->bridge.funcs = &cdns_mhdp_bridge_funcs;
-       mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
-                          DRM_BRIDGE_OP_HPD;
+       mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
+       if (!mhdp->no_hpd)
+               mhdp->bridge.ops |= DRM_BRIDGE_OP_HPD;
        mhdp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
        if (mhdp->info)
                mhdp->bridge.timings = mhdp->info->timings;
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h 
b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
index bedddd510d17..6786ccb51387 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
@@ -388,6 +388,7 @@ struct cdns_mhdp_device {
 
        bool link_up;
        bool plugged;
+       bool no_hpd;
 
        /*
         * "start_lock" protects the access to bridge_attached and
-- 
2.25.1

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