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From:   Manu Gautam <mgautam@codeaurora.org>
To:     Kishon Vijay Abraham I <kishon@ti.com>
Cc:     linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org,
        Vivek Gautam <vivek.gautam@codeaurora.org>,
        Manu Gautam <mgautam@codeaurora.org>,
        Varadarajan Narayanan <varada@codeaurora.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Fengguang Wu <fengguang.wu@intel.com>,
        Wei Yongjun <weiyongjun1@huawei.com>,
        linux-kernel@vger.kernel.org (open list:GENERIC PHY FRAMEWORK)
Subject: [PATCH v3 01/16] phy: qcom-qmp: Fix phy pipe clock gating
Date:   Tue, 21 Nov 2017 14:53:11 +0530
Message-Id: <1511256206-1587-2-git-send-email-mgautam@codeaurora.org>
In-Reply-To: <1511256206-1587-1-git-send-email-mgautam@codeaurora.org>
References: <1511256206-1587-1-git-send-email-mgautam@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Vivek Gautam <vivek.gautam@codeaurora.org>

Pipe clock comes out of the phy and is available as long as
the phy is turned on. Clock controller fails to gate this
clock after the phy is turned off and generates a warning.

/ # [   33.048561] gcc_usb3_phy_pipe_clk status stuck at 'on'
[   33.048585] ------------[ cut here ]------------
[   33.052621] WARNING: CPU: 1 PID: 18 at ../drivers/clk/qcom/clk-branch.c:97 clk_branch_wait+0xf0/0x108
[   33.057384] Modules linked in:
[   33.066497] CPU: 1 PID: 18 Comm: kworker/1:0 Tainted: G        W       4.12.0-rc7-00024-gfe926e34c36d-dirty #96
[   33.069451] Hardware name: Qualcomm Technologies, Inc. DB820c (DT)
...
[   33.278565] [<ffff00000849b27c>] clk_branch_wait+0xf0/0x108
[   33.286375] [<ffff00000849b2f4>] clk_branch2_disable+0x28/0x34
[   33.291761] [<ffff0000084868dc>] clk_core_disable+0x5c/0x88
[   33.297660] [<ffff000008487d68>] clk_core_disable_lock+0x20/0x34
[   33.303129] [<ffff000008487d98>] clk_disable+0x1c/0x24
[   33.309384] [<ffff0000083ccd78>] qcom_qmp_phy_poweroff+0x20/0x48
[   33.314328] [<ffff0000083c53f4>] phy_power_off+0x80/0xdc
[   33.320492] [<ffff00000875c950>] dwc3_core_exit+0x94/0xa0
[   33.325784] [<ffff00000875c9ac>] dwc3_suspend_common+0x50/0x60
[   33.331080] [<ffff00000875ca04>] dwc3_runtime_suspend+0x48/0x6c
[   33.336810] [<ffff0000085b82f4>] pm_generic_runtime_suspend+0x28/0x38
[   33.342627] [<ffff0000085bace0>] __rpm_callback+0x150/0x254
[   33.349222] [<ffff0000085bae08>] rpm_callback+0x24/0x78
[   33.354604] [<ffff0000085b9fd8>] rpm_suspend+0xe0/0x4e4
[   33.359813] [<ffff0000085bb784>] pm_runtime_work+0xdc/0xf0
[   33.365028] [<ffff0000080d7b30>] process_one_work+0x12c/0x28c
[   33.370576] [<ffff0000080d7ce8>] worker_thread+0x58/0x3b8
[   33.376393] [<ffff0000080dd4a8>] kthread+0x100/0x12c
[   33.381776] [<ffff0000080836c0>] ret_from_fork+0x10/0x50

Fix this by enabling pipe clock at the end of phy_init(), and disabling
it as the first thing in phy_exit().

Fixes: e78f3d15e115 ("phy: qcom-qmp: new qmp phy driver for qcom-chipsets")
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
---
 drivers/phy/qualcomm/phy-qcom-qmp.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
index e17f035..76acaec 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -731,19 +731,10 @@ static int qcom_qmp_phy_poweron(struct phy *phy)
 
 	/* turn on regulator supplies */
 	ret = regulator_bulk_enable(num, qmp->vregs);
-	if (ret) {
+	if (ret)
 		dev_err(qmp->dev, "failed to enable regulators, err=%d\n", ret);
-		return ret;
-	}
-
-	ret = clk_prepare_enable(qphy->pipe_clk);
-	if (ret) {
-		dev_err(qmp->dev, "pipe_clk enable failed, err=%d\n", ret);
-		regulator_bulk_disable(num, qmp->vregs);
-		return ret;
-	}
 
-	return 0;
+	return ret;
 }
 
 static int qcom_qmp_phy_poweroff(struct phy *phy)
@@ -751,8 +742,6 @@ static int qcom_qmp_phy_poweroff(struct phy *phy)
 	struct qmp_phy *qphy = phy_get_drvdata(phy);
 	struct qcom_qmp *qmp = qphy->qmp;
 
-	clk_disable_unprepare(qphy->pipe_clk);
-
 	regulator_bulk_disable(qmp->cfg->num_vregs, qmp->vregs);
 
 	return 0;
@@ -915,7 +904,14 @@ static int qcom_qmp_phy_init(struct phy *phy)
 		goto err_pcs_ready;
 	}
 
-	return ret;
+	/* phy is initialized; we can turn on the pipe clock now */
+	ret = clk_prepare_enable(qphy->pipe_clk);
+	if (ret) {
+		dev_err(qmp->dev, "pipe_clk enable failed, err=%d\n", ret);
+		goto err_pcs_ready;
+	}
+
+	return 0;
 
 err_pcs_ready:
 	if (cfg->has_lane_rst)
@@ -936,6 +932,8 @@ static int qcom_qmp_phy_exit(struct phy *phy)
 	const struct qmp_phy_cfg *cfg = qmp->cfg;
 	int i = cfg->num_clks;
 
+	clk_disable_unprepare(qphy->pipe_clk);
+
 	/* PHY reset */
 	qphy_setbits(qphy->pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


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