linux-kernel - [PATCH] phy: qcom: edp: Postpone clk_set

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Message-Id: <20220805154432.546740-1-bjorn.andersson@linaro.org>
Date:   Fri,  5 Aug 2022 08:44:32 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
        linux-kernel@...r.kernel.org, johan+linaro@...nel.org
Subject: [PATCH] phy: qcom: edp: Postpone clk_set_rate until the PLL is up

When the platform was booted with the involved clocks enabled the
clk_set_rate() of the link and pixel clocks will perculate to the
children, which will fail to update because the PHY driver has just shut
down the PLL.

Postpone the clock rate updates until the PLL is back online to avoid
reconfiguring the clocks while the PLL is not ticking.

Fixes: f199223cb490 ("phy: qcom: Introduce new eDP PHY driver")
Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---
 drivers/phy/qualcomm/phy-qcom-edp.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-edp.c b/drivers/phy/qualcomm/phy-qcom-edp.c
index 7e3570789845..b66b83c388ed 100644
--- a/drivers/phy/qualcomm/phy-qcom-edp.c
+++ b/drivers/phy/qualcomm/phy-qcom-edp.c
@@ -272,31 +272,30 @@ static int qcom_edp_configure_pll(const struct qcom_edp *edp)
 	return 0;
 }
 
-static int qcom_edp_set_vco_div(const struct qcom_edp *edp)
+static int qcom_edp_set_vco_div(const struct qcom_edp *edp, unsigned long *pixel_freq)
 {
 	const struct phy_configure_opts_dp *dp_opts = &edp->dp_opts;
-	unsigned long pixel_freq;
 	u32 vco_div;
 
 	switch (dp_opts->link_rate) {
 	case 1620:
 		vco_div = 0x1;
-		pixel_freq = 1620000000UL / 2;
+		*pixel_freq = 1620000000UL / 2;
 		break;
 
 	case 2700:
 		vco_div = 0x1;
-		pixel_freq = 2700000000UL / 2;
+		*pixel_freq = 2700000000UL / 2;
 		break;
 
 	case 5400:
 		vco_div = 0x2;
-		pixel_freq = 5400000000UL / 4;
+		*pixel_freq = 5400000000UL / 4;
 		break;
 
 	case 8100:
 		vco_div = 0x0;
-		pixel_freq = 8100000000UL / 6;
+		*pixel_freq = 8100000000UL / 6;
 		break;
 
 	default:
@@ -306,15 +305,13 @@ static int qcom_edp_set_vco_div(const struct qcom_edp *edp)
 
 	writel(vco_div, edp->edp + DP_PHY_VCO_DIV);
 
-	clk_set_rate(edp->dp_link_hw.clk, dp_opts->link_rate * 100000);
-	clk_set_rate(edp->dp_pixel_hw.clk, pixel_freq);
-
 	return 0;
 }
 
 static int qcom_edp_phy_power_on(struct phy *phy)
 {
 	const struct qcom_edp *edp = phy_get_drvdata(phy);
+	unsigned long pixel_freq;
 	int timeout;
 	int ret;
 	u32 val;
@@ -363,7 +360,7 @@ static int qcom_edp_phy_power_on(struct phy *phy)
 	writel(0x01, edp->tx1 + TXn_TRAN_DRVR_EMP_EN);
 	writel(0x04, edp->tx1 + TXn_TX_BAND);
 
-	ret = qcom_edp_set_vco_div(edp);
+	ret = qcom_edp_set_vco_div(edp, &pixel_freq);
 	if (ret)
 		return ret;
 
@@ -409,8 +406,15 @@ static int qcom_edp_phy_power_on(struct phy *phy)
 
 	writel(0x19, edp->edp + DP_PHY_CFG);
 
-	return readl_poll_timeout(edp->edp + DP_PHY_STATUS,
-				  val, val & BIT(1), 500, 10000);
+	ret = readl_poll_timeout(edp->edp + DP_PHY_STATUS,
+				 val, val & BIT(1), 500, 10000);
+	if (ret)
+		return ret;
+
+	clk_set_rate(edp->dp_link_hw.clk, edp->dp_opts.link_rate * 100000);
+	clk_set_rate(edp->dp_pixel_hw.clk, pixel_freq);
+
+	return 0;
 }
 
 static int qcom_edp_phy_power_off(struct phy *phy)
-- 
2.35.1