linux-kernel - [PATCH v6 7/8] drm/msm/dp: Support edp/dp without hpd

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Date:   Wed, 30 Mar 2022 21:32:58 +0530
From:   Sankeerth Billakanti <quic_sbillaka@...cinc.com>
To:     <dri-devel@...ts.freedesktop.org>, <linux-arm-msm@...r.kernel.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>
CC:     Sankeerth Billakanti <quic_sbillaka@...cinc.com>,
        <robdclark@...il.com>, <seanpaul@...omium.org>,
        <swboyd@...omium.org>, <quic_kalyant@...cinc.com>,
        <quic_abhinavk@...cinc.com>, <dianders@...omium.org>,
        <quic_khsieh@...cinc.com>, <bjorn.andersson@...aro.org>,
        <sean@...rly.run>, <airlied@...ux.ie>, <daniel@...ll.ch>,
        <dmitry.baryshkov@...aro.org>, <quic_vproddut@...cinc.com>,
        <quic_aravindh@...cinc.com>
Subject: [PATCH v6 7/8] drm/msm/dp: Support edp/dp without hpd

Some eDP sinks or platform boards will not support hpd.
This patch adds support for those cases.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@...cinc.com>
---
 drivers/gpu/drm/msm/dp/dp_catalog.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
index 1809ce2..8f1fc71 100644
--- a/drivers/gpu/drm/msm/dp/dp_catalog.c
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
@@ -244,10 +244,17 @@ void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog)
 
 int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog)
 {
-	u32 state;
+	u32 state, hpd_en;
 	struct dp_catalog_private *catalog = container_of(dp_catalog,
 				struct dp_catalog_private, dp_catalog);
 
+	hpd_en = dp_read_aux(catalog, REG_DP_DP_HPD_CTRL);
+	hpd_en &= DP_DP_HPD_CTRL_HPD_EN;
+
+	/* no-hpd case */
+	if (!hpd_en)
+		return 0;
+
 	/* poll for hpd connected status every 2ms and timeout after 500ms */
 	return readl_poll_timeout(catalog->io->dp_controller.aux.base +
 				REG_DP_DP_HPD_INT_STATUS,
@@ -586,8 +593,10 @@ void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog)
 	reftimer |= DP_DP_HPD_REFTIMER_ENABLE;
 	dp_write_aux(catalog, REG_DP_DP_HPD_REFTIMER, reftimer);
 
-	/* Enable HPD */
-	dp_write_aux(catalog, REG_DP_DP_HPD_CTRL, DP_DP_HPD_CTRL_HPD_EN);
+	/* Enable HPD if supported*/
+	if (!of_property_read_bool(catalog->dev->of_node, "no-hpd"))
+		dp_write_aux(catalog, REG_DP_DP_HPD_CTRL,
+				DP_DP_HPD_CTRL_HPD_EN);
 }
 
 u32 dp_catalog_link_is_connected(struct dp_catalog *dp_catalog)
-- 
2.7.4