[PATCH v1 1/6] phy: qcom-qmp: Fix phy pipe clock gating

[Manu Gautam]

From: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
index 78ca628..a230c7b 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -610,19 +610,10 @@ 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)
@@ -630,8 +621,6 @@ 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;
@@ -797,7 +786,14 @@ 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)
@@ -818,6 +814,8 @@ 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);
 
-- 
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