linux-kernel - [PATCH 1/6] phy: qcom-qmp: Enable pipe_clk before checking USB3 PHY

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Date:   Fri, 16 Mar 2018 15:14:54 +0530
From:   Manu Gautam <mgautam@...eaurora.org>
To:     Kishon Vijay Abraham I <kishon@...com>
Cc:     linux-arm-msm@...r.kernel.org,
        Manu Gautam <mgautam@...eaurora.org>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Varadarajan Narayanan <varada@...eaurora.org>,
        Fengguang Wu <fengguang.wu@...el.com>,
        Wei Yongjun <weiyongjun1@...wei.com>,
        linux-kernel@...r.kernel.org (open list:GENERIC PHY FRAMEWORK)
Subject: [PATCH 1/6] phy: qcom-qmp: Enable pipe_clk before checking USB3 PHY_STATUS

QMP PHY for USB mode requires pipe_clk for calibration and PLL lock
to take place. This lock is output from PHY to GCC clock_ctl and then
fed back to QMP PHY and is output from PHY only after PHY is reset
and initialized, hence it can't be enabled too early in initialization
sequence.

Signed-off-by: Manu Gautam <mgautam@...eaurora.org>
---
 drivers/phy/qualcomm/phy-qcom-qmp.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
index 6470c5d..73aa282 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -797,8 +797,13 @@ static int qcom_qmp_phy_poweron(struct phy *phy)
 {
 	struct qmp_phy *qphy = phy_get_drvdata(phy);
 	struct qcom_qmp *qmp = qphy->qmp;
+	const struct qmp_phy_cfg *cfg = qmp->cfg;
 	int ret;
 
+	/* Not needed for USB3 PHY as pipe_clk is enabled from phy_init */
+	if (cfg->type == PHY_TYPE_USB3)
+		return 0;
+
 	ret = clk_prepare_enable(qphy->pipe_clk);
 	if (ret)
 		dev_err(qmp->dev, "pipe_clk enable failed, err=%d\n", ret);
@@ -1008,6 +1013,19 @@ static int qcom_qmp_phy_init(struct phy *phy)
 	status = pcs + cfg->regs[QPHY_PCS_READY_STATUS];
 	mask = cfg->mask_pcs_ready;
 
+	/* USB3 PHY requires pipe_clk for PLL lock and calibration */
+	if (cfg->type == PHY_TYPE_USB3) {
+		ret = clk_prepare_enable(qphy->pipe_clk);
+		if (ret)
+			dev_err(qmp->dev, "pipe_clk enable err=%d\n", ret);
+		/*
+		 * Ignore this error as pipe_clk might take some time to get
+		 * enabled. In any case following check for PHY PLL lock would
+		 * timeout below if there is a fatal error and clock is not fed
+		 * to PHY
+		 */
+	}
+
 	ret = readl_poll_timeout(status, val, !(val & mask), 1,
 				 PHY_INIT_COMPLETE_TIMEOUT);
 	if (ret) {
-- 
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