[PATCH 04/10] phy: qcom-ipq806x-usb: add MSM8974 HS PHY support

[Dmitry Baryshkov]

The MSM8974 DWC3 wrapper embeds the same generation of QSCRATCH
controlled Synopsys 28nm HS PHY as IPQ806x, but the driver only knows
the IPQ806x variants, so on MSM8974 the controller runs on whatever
PHY state the bootloader left behind.

Add the qcom,msm8974-usb-phy-hs compatible with its own init
sequence: unlike the IPQ806x one, it must not overwrite the whole
PHY_CTRL register, as the power-on values of the reference frequency
selection straps have to be preserved. Only enable the UTMI clock and
the DP/DM MPM clamps, signal VBUS valid towards the link, and disable
retention.

Assisted-by: Claude:claude-fable-5
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
 drivers/phy/qualcomm/phy-qcom-ipq806x-usb.c | 35 +++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-ipq806x-usb.c b/drivers/phy/qualcomm/phy-qcom-ipq806x-usb.c
index f22c0000479f..21b59d4ca8d2 100644
--- a/drivers/phy/qualcomm/phy-qcom-ipq806x-usb.c
+++ b/drivers/phy/qualcomm/phy-qcom-ipq806x-usb.c
@@ -17,6 +17,7 @@
 #define HSUSB_PHY_CTRL_REG		(0x10)
 
 /* PHY_CTRL_REG */
+#define HSUSB_CLAMP_MPM_DPSE_DMSE_EN_N	BIT(26)
 #define HSUSB_CTRL_DMSEHV_CLAMP		BIT(24)
 #define HSUSB_CTRL_USB2_SUSPEND		BIT(23)
 #define HSUSB_CTRL_UTMI_CLK_EN		BIT(21)
@@ -27,9 +28,13 @@
 #define HSUSB_CTRL_ID_HV_CLAMP		BIT(9)
 #define HSUSB_CTRL_OTGSESSVLD_CLAMP	BIT(8)
 #define HSUSB_CTRL_CLAMP_EN		BIT(7)
+#define HSUSB_CTRL_CLAMP_MPM_DPSE_DMSE	BIT(26)
 #define HSUSB_CTRL_RETENABLEN		BIT(1)
 #define HSUSB_CTRL_POR			BIT(0)
 
+/* PHY parameter override register (eye diagram tuning) */
+#define HSUSB_PARAMETER_OVERRIDE_X_REG	(0x14)
+
 /* QSCRATCH_GENERAL_CFG */
 #define HSUSB_GCFG_XHCI_REV		BIT(2)
 
@@ -115,6 +120,8 @@
 #define LATCH_SLEEP				40
 #define LATCH_TIMEOUT				100
 
+struct phy_drvdata;
+
 struct usb_phy {
 	void __iomem		*base;
 	struct device		*dev;
@@ -123,11 +130,14 @@ struct usb_phy {
 	u32			rx_eq;
 	u32			tx_deamp_3_5db;
 	u32			mpll;
+	const struct phy_drvdata *drvdata;
 };
 
 struct phy_drvdata {
 	struct phy_ops	ops;
 	u32		clk_rate;
+	u32		hs_tune_val;
+	u32		fsel;
 };
 
 /**
@@ -273,7 +283,8 @@ static int qcom_ipq806x_usb_hs_phy_init(struct phy *phy)
 		HSUSB_CTRL_RETENABLEN  | HSUSB_CTRL_COMMONONN |
 		HSUSB_CTRL_OTGSESSVLD_CLAMP | HSUSB_CTRL_ID_HV_CLAMP |
 		HSUSB_CTRL_UTMI_OTG_VBUS_VALID | HSUSB_CTRL_UTMI_CLK_EN |
-		HSUSB_CTRL_CLAMP_EN | 0x70;
+		HSUSB_CTRL_CLAMP_EN | HSUSB_CLAMP_MPM_DPSE_DMSE_EN_N |
+		phy_dwc3->drvdata->fsel;
 
 	/* use core clock if external reference is not present */
 	if (!phy_dwc3->xo_clk)
@@ -282,9 +293,14 @@ static int qcom_ipq806x_usb_hs_phy_init(struct phy *phy)
 	writel(val, phy_dwc3->base + HSUSB_PHY_CTRL_REG);
 	usleep_range(2000, 2200);
 
-	/* Disable (bypass) VBUS and ID filters */
+	/* Set XHCI_REV bit (2) to 1 - XHCI version 1.0 */
 	writel(HSUSB_GCFG_XHCI_REV, phy_dwc3->base + QSCRATCH_GENERAL_CFG);
 
+	if (phy_dwc3->drvdata->hs_tune_val)
+		usb_phy_write_readback(phy_dwc3, HSUSB_PARAMETER_OVERRIDE_X_REG,
+				       0x03ffffff,
+				       phy_dwc3->drvdata->hs_tune_val);
+
 	return 0;
 }
 
@@ -458,6 +474,18 @@ static const struct phy_drvdata qcom_ipq806x_usb_hs_drvdata = {
 		.owner		= THIS_MODULE,
 	},
 	.clk_rate = 60000000,
+	.fsel = 0x70,
+};
+
+static const struct phy_drvdata qcom_msm8974_usb_hs_drvdata = {
+	.ops = {
+		.init		= qcom_ipq806x_usb_hs_phy_init,
+		.exit		= qcom_ipq806x_usb_hs_phy_exit,
+		.owner		= THIS_MODULE,
+	},
+	.clk_rate = 60000000,
+	.hs_tune_val = 0x00d191a4,
+	.fsel = 0x30,
 };
 
 static const struct phy_drvdata qcom_ipq806x_usb_ss_drvdata = {
@@ -474,6 +502,8 @@ static const struct of_device_id qcom_ipq806x_usb_phy_table[] = {
 	  .data = &qcom_ipq806x_usb_hs_drvdata },
 	{ .compatible = "qcom,ipq806x-usb-phy-ss",
 	  .data = &qcom_ipq806x_usb_ss_drvdata },
+	{ .compatible = "qcom,msm8974-usb-phy-hs",
+	  .data = &qcom_msm8974_usb_hs_drvdata },
 	{ /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, qcom_ipq806x_usb_phy_table);
@@ -492,6 +522,7 @@ static int qcom_ipq806x_usb_phy_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	data = of_device_get_match_data(&pdev->dev);
+	phy_dwc3->drvdata = data;
 
 	phy_dwc3->dev = &pdev->dev;
 

-- 
2.47.3