linux-kernel - [PATCH] drm/msm/dp: keep aux channel up when power of dp phy

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Date:   Wed, 26 May 2021 16:49:49 -0700
From:   Kuogee Hsieh <khsieh@...eaurora.org>
To:     robdclark@...il.com, sean@...rly.run, swboyd@...omium.org,
        vkoul@...nel.org, agross@...nel.org, bjorn.andersson@...aro.org
Cc:     abhinavk@...eaurora.org, aravindh@...eaurora.org,
        khsieh@...eaurora.org, freedreno@...ts.freedesktop.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm/msm/dp: keep aux channel up when power of dp phy

Aux channel is used to perform management function and should be
running in parallel with main link. Therefore should only power
down main link and keep aux channel running when power down phy.

Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c    |  4 ----
 drivers/phy/qualcomm/phy-qcom-qmp.c | 11 +++++++++--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 5115c05..5f93c64 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1844,10 +1844,6 @@ int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl)
 
 	phy_power_off(phy);
 
-	/* aux channel down, reinit phy */
-	phy_exit(phy);
-	phy_init(phy);
-
 	DRM_DEBUG_DP("DP off link/stream done\n");
 	return ret;
 }
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
index b122e63..567e32e 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -3214,12 +3214,19 @@ static int qcom_qmp_phy_power_off(struct phy *phy)
 {
 	struct qmp_phy *qphy = phy_get_drvdata(phy);
 	const struct qmp_phy_cfg *cfg = qphy->cfg;
+	u32 val;
 
 	clk_disable_unprepare(qphy->pipe_clk);
 
 	if (cfg->type == PHY_TYPE_DP) {
-		/* Assert DP PHY power down */
-		writel(DP_PHY_PD_CTL_PSR_PWRDN, qphy->pcs + QSERDES_V3_DP_PHY_PD_CTL);
+		/*
+		 * Assert DP PHY LANE_0_1, LANE_2_3, PSR power down
+		 * keep aux channel up
+		 */
+		val = DP_PHY_PD_CTL_PWRDN | DP_PHY_PD_CTL_AUX_PWRDN |
+			DP_PHY_PD_CTL_PLL_PWRDN | DP_PHY_PD_CTL_DP_CLAMP_EN |
+			DP_PHY_PD_CTL_PSR_PWRDN;
+		writel(val, qphy->pcs + QSERDES_V3_DP_PHY_PD_CTL);
 	} else {
 		/* PHY reset */
 		if (!cfg->no_pcs_sw_reset)
-- 
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