linux-kernel - [PATCH v3 05/16] phy: qcom-qmp: Fix PHY block reset sequence

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Date:   Tue, 21 Nov 2017 14:53:15 +0530
From:   Manu Gautam <mgautam@...eaurora.org>
To:     Kishon Vijay Abraham I <kishon@...com>
Cc:     linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        Manu Gautam <mgautam@...eaurora.org>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Varadarajan Narayanan <varada@...eaurora.org>,
        Heiko Stuebner <heiko@...ech.de>,
        Fengguang Wu <fengguang.wu@...el.com>,
        Wei Yongjun <weiyongjun1@...wei.com>,
        linux-kernel@...r.kernel.org (open list:GENERIC PHY FRAMEWORK)
Subject: [PATCH v3 05/16] phy: qcom-qmp: Fix PHY block reset sequence

PHY block or asynchronous reset requires signal
to be asserted before de-asserting. Driver is only
de-asserting signal which is already low, hence
reset operation is a no-op. Fix this by asserting
signal first. Also, resetting requires PHY clocks
to be turned ON only after reset is finished. Fix
that as well.

Signed-off-by: Manu Gautam <mgautam@...eaurora.org>
---
 drivers/phy/qualcomm/phy-qcom-qmp.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
index 2f427e3..aa27757 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -739,13 +739,16 @@ static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
 		return ret;
 	}
 
-	ret = clk_bulk_prepare_enable(cfg->num_clks, qmp->clks);
-	if (ret) {
-		dev_err(qmp->dev, "failed to enable clks, err=%d\n", ret);
-		goto err_clk_enable;
+	for (i = 0; i < cfg->num_resets; i++) {
+		ret = reset_control_assert(qmp->resets[i]);
+		if (ret) {
+			dev_err(qmp->dev, "%s reset assert failed\n",
+				cfg->reset_list[i]);
+			goto err_rst_assert;
+		}
 	}
 
-	for (i = 0; i < cfg->num_resets; i++) {
+	for (i = cfg->num_resets - 1; i >= 0; i--) {
 		ret = reset_control_deassert(qmp->resets[i]);
 		if (ret) {
 			dev_err(qmp->dev, "%s reset deassert failed\n",
@@ -754,6 +757,12 @@ static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
 		}
 	}
 
+	ret = clk_bulk_prepare_enable(cfg->num_clks, qmp->clks);
+	if (ret) {
+		dev_err(qmp->dev, "failed to enable clks, err=%d\n", ret);
+		goto err_rst;
+	}
+
 	if (cfg->has_phy_com_ctrl)
 		qphy_setbits(serdes, cfg->regs[QPHY_COM_POWER_DOWN_CONTROL],
 			     SW_PWRDN);
@@ -778,7 +787,7 @@ static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
 		if (ret) {
 			dev_err(qmp->dev,
 				"phy common block init timed-out\n");
-			goto err_rst;
+			goto err_com_init;
 		}
 	}
 
@@ -786,11 +795,12 @@ static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
 
 	return 0;
 
+err_com_init:
+	clk_bulk_disable_unprepare(cfg->num_clks, qmp->clks);
 err_rst:
-	while (--i >= 0)
+	while (++i < cfg->num_resets)
 		reset_control_assert(qmp->resets[i]);
-	clk_bulk_disable_unprepare(cfg->num_clks, qmp->clks);
-err_clk_enable:
+err_rst_assert:
 	regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
 	mutex_unlock(&qmp->phy_mutex);
 
-- 
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