[PATCH v3 1/3] phy: qcom-snps-femto-v2: properly enable ref clock

[Adrien Thierry]

The driver is not enabling the ref clock, which thus gets disabled by
the clk_disable_unused initcall. This leads to the dwc3 controller
failing to initialize if probed after clk_disable_unused is called, for
instance when the driver is built as a module.

To fix this, switch to the clk_bulk API to handle both cfg_ahb and ref
clocks at the proper places.

Note that the cfg_ahb clock is currently not used by any device tree
instantiation of the PHY. Work needs to be done separately to fix this.

Link: https://lore.kernel.org/linux-arm-msm/ZEqvy+khHeTkC2hf@fedora/
Fixes: 51e8114f80d0 ("phy: qcom-snps: Add SNPS USB PHY driver for QCOM based SOCs")
Reviewed-by: Andrew Halaney <ahalaney at redhat.com>
Signed-off-by: Adrien Thierry <athierry at redhat.com>
---
 drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 67 ++++++++++++++-----
 1 file changed, 49 insertions(+), 18 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
index 6c237f3cc66d..ce1d2f8b568a 100644
--- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
+++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
@@ -110,11 +110,13 @@ struct phy_override_seq {
 /**
  * struct qcom_snps_hsphy - snps hs phy attributes
  *
+ * @dev: device structure
+ *
  * @phy: generic phy
  * @base: iomapped memory space for snps hs phy
  *
- * @cfg_ahb_clk: AHB2PHY interface clock
- * @ref_clk: phy reference clock
+ * @num_clks: number of clocks
+ * @clks: array of clocks
  * @phy_reset: phy reset control
  * @vregs: regulator supplies bulk data
  * @phy_initialized: if PHY has been initialized correctly
@@ -122,11 +124,13 @@ struct phy_override_seq {
  * @update_seq_cfg: tuning parameters for phy init
  */
 struct qcom_snps_hsphy {
+	struct device *dev;
+
 	struct phy *phy;
 	void __iomem *base;
 
-	struct clk *cfg_ahb_clk;
-	struct clk *ref_clk;
+	int num_clks;
+	struct clk_bulk_data *clks;
 	struct reset_control *phy_reset;
 	struct regulator_bulk_data vregs[SNPS_HS_NUM_VREGS];
 
@@ -135,6 +139,32 @@ struct qcom_snps_hsphy {
 	struct phy_override_seq update_seq_cfg[NUM_HSPHY_TUNING_PARAMS];
 };
 
+static int qcom_snps_hsphy_clk_init(struct qcom_snps_hsphy *hsphy)
+{
+	struct device *dev = hsphy->dev;
+
+	hsphy->num_clks = 2;
+	hsphy->clks = devm_kcalloc(dev, hsphy->num_clks, sizeof(*hsphy->clks), GFP_KERNEL);
+	if (!hsphy->clks)
+		return -ENOMEM;
+
+	/*
+	 * HACK: For cfg_ahb clock, use devm_clk_get_optional() because currently no device
+	 * tree instantiation of the PHY is using the clock. This needs to be fixed in order
+	 * for this code to be able to use devm_clk_bulk_get().
+	 */
+	hsphy->clks[0].id = "cfg_ahb";
+	hsphy->clks[0].clk = devm_clk_get_optional(dev, "cfg_ahb");
+
+	hsphy->clks[1].id = "ref";
+	hsphy->clks[1].clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(hsphy->clks[1].clk))
+		return dev_err_probe(dev, PTR_ERR(hsphy->clks[1].clk),
+				     "failed to get ref clk\n");
+
+	return 0;
+}
+
 static inline void qcom_snps_hsphy_write_mask(void __iomem *base, u32 offset,
 						u32 mask, u32 val)
 {
@@ -165,7 +195,7 @@ static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy)
 					   0, USB2_AUTO_RESUME);
 	}
 
-	clk_disable_unprepare(hsphy->cfg_ahb_clk);
+	clk_bulk_disable_unprepare(hsphy->num_clks, hsphy->clks);
 	return 0;
 }
 
@@ -175,9 +205,9 @@ static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy)
 
 	dev_dbg(&hsphy->phy->dev, "Resume QCOM SNPS PHY, mode\n");
 
-	ret = clk_prepare_enable(hsphy->cfg_ahb_clk);
+	ret = clk_bulk_prepare_enable(hsphy->num_clks, hsphy->clks);
 	if (ret) {
-		dev_err(&hsphy->phy->dev, "failed to enable cfg ahb clock\n");
+		dev_err(&hsphy->phy->dev, "failed to enable clocks\n");
 		return ret;
 	}
 
@@ -374,16 +404,16 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 	if (ret)
 		return ret;
 
-	ret = clk_prepare_enable(hsphy->cfg_ahb_clk);
+	ret = clk_bulk_prepare_enable(hsphy->num_clks, hsphy->clks);
 	if (ret) {
-		dev_err(&phy->dev, "failed to enable cfg ahb clock, %d\n", ret);
+		dev_err(&phy->dev, "failed to enable clocks, %d\n", ret);
 		goto poweroff_phy;
 	}
 
 	ret = reset_control_assert(hsphy->phy_reset);
 	if (ret) {
 		dev_err(&phy->dev, "failed to assert phy_reset, %d\n", ret);
-		goto disable_ahb_clk;
+		goto disable_clks;
 	}
 
 	usleep_range(100, 150);
@@ -391,7 +421,7 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 	ret = reset_control_deassert(hsphy->phy_reset);
 	if (ret) {
 		dev_err(&phy->dev, "failed to de-assert phy_reset, %d\n", ret);
-		goto disable_ahb_clk;
+		goto disable_clks;
 	}
 
 	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_CFG0,
@@ -448,8 +478,8 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 
 	return 0;
 
-disable_ahb_clk:
-	clk_disable_unprepare(hsphy->cfg_ahb_clk);
+disable_clks:
+	clk_bulk_disable_unprepare(hsphy->num_clks, hsphy->clks);
 poweroff_phy:
 	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
 
@@ -461,7 +491,7 @@ static int qcom_snps_hsphy_exit(struct phy *phy)
 	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
 
 	reset_control_assert(hsphy->phy_reset);
-	clk_disable_unprepare(hsphy->cfg_ahb_clk);
+	clk_bulk_disable_unprepare(hsphy->num_clks, hsphy->clks);
 	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
 	hsphy->phy_initialized = false;
 
@@ -554,14 +584,15 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 	if (!hsphy)
 		return -ENOMEM;
 
+	hsphy->dev = dev;
+
 	hsphy->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(hsphy->base))
 		return PTR_ERR(hsphy->base);
 
-	hsphy->ref_clk = devm_clk_get(dev, "ref");
-	if (IS_ERR(hsphy->ref_clk))
-		return dev_err_probe(dev, PTR_ERR(hsphy->ref_clk),
-				     "failed to get ref clk\n");
+	ret = qcom_snps_hsphy_clk_init(hsphy);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to initialize clocks\n");
 
 	hsphy->phy_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 	if (IS_ERR(hsphy->phy_reset)) {
-- 
2.40.1