[PATCH v2 2/3] phy: qcom-snps: Add support for overriding phy tuning parameters

[Sandeep Maheswaram]

Added support for overriding x0,x1,x2,x3 params for SNPS PHY by reading
values from device tree.

Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
---
 drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 192 ++++++++++++++++++++++++++
 1 file changed, 192 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
index 7e61202..b5aa06d 100644
--- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
+++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
@@ -51,6 +51,48 @@
 #define USB2_SUSPEND_N				BIT(2)
 #define USB2_SUSPEND_N_SEL			BIT(3)
 
+#define USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X0	(0x6c)
+
+/*USB_PHY_HS_PHY_OVERRIDE_X0 register bits*/
+#define HS_DISCONNECT_MASK			GENMASK(2, 0)
+#define HS_DISCONNECT_SHIFT			0x0
+
+#define SQUELCH_DETECTOR_MASK			GENMASK(7, 5)
+#define SQUELCH_DETECTOR_SHIFT			0x5
+
+
+#define USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X1	(0x70)
+
+/*USB_PHY_HS_PHY_OVERRIDE_X1 register bits*/
+#define HS_AMPLITUDE_MASK			GENMASK(3, 0)
+#define HS_AMPLITUDE_SHIFT			0x0
+
+#define PREEMPHASIS_DURATION_MASK		BIT(5)
+#define PREEMPHASIS_DURATION_SHIFT		0x5
+
+#define PREEMPHASIS_AMPLITUDE_MASK		GENMASK(7, 6)
+#define PREEMPHASIS_AMPLITUDE_SHIFT		0x6
+
+
+#define USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X2	(0x74)
+
+/*USB_PHY_HS_PHY_OVERRIDE_X2 register bits*/
+#define HS_RISE_FALL_MASK			GENMASK(1, 0)
+#define HS_RISE_FALL_SHIFT			0x0
+
+#define HS_CROSSOVER_VOLTAGE_MASK		GENMASK(3, 2)
+#define HS_CROSSOVER_VOLTAGE_SHIFT		0x2
+
+#define HS_OUTPUT_IMPEDANCE_MASK		GENMASK(5, 4)
+#define HS_OUTPUT_IMPEDANCE_SHIFT		0x4
+
+
+#define USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X3	(0x78)
+
+/*USB_PHY_HS_PHY_OVERRIDE_X3 register bits*/
+#define LS_FS_OUTPUT_IMPEDANCE_MASK		GENMASK(3, 0)
+#define LS_FS_OUTPUT_IMPEDANCE_SHIFT		0x0
+
 #define USB2_PHY_USB_PHY_CFG0			(0x94)
 #define UTMI_PHY_DATAPATH_CTRL_OVERRIDE_EN	BIT(0)
 #define UTMI_PHY_CMN_CTRL_OVERRIDE_EN		BIT(1)
@@ -65,6 +107,43 @@ static const char * const qcom_snps_hsphy_vreg_names[] = {
 
 #define SNPS_HS_NUM_VREGS		ARRAY_SIZE(qcom_snps_hsphy_vreg_names)
 
+/* struct override_param - structure holding snps phy overriding param
+ * set override true if the  device tree property exists and read and assign
+ * to value
+ */
+struct override_param {
+	bool override;
+	u8 value;
+};
+
+/*struct override_params - structure holding snps phy overriding params
+ * @hs_disconnect: disconnect threshold
+ * @squelch_detector: threshold to detect valid high-speed data
+ * @hs_amplitude: high-speed DC level voltage
+ * @preemphasis_duration: duration for which the HS pre-emphasis current
+ *  is sourced onto DP<#> or DM<#>
+ * @preemphasis_amplitude: current sourced to DP<#> and DM<#> after
+ *  a J-to-K or K-to-J transition.
+ * @hs_rise_fall_time: rise/fall times of the high-speed waveform
+ * @hs_crossover_voltage: voltage at which the DP<#> and DM<#>
+ *  signals cross while transmitting in HS mode
+ * @hs_output_impedance: driver source impedance to compensate for added series
+ *  resistance on the USB
+ * @ls_fs_output_impedance: low and full-speed single-ended source
+ *  impedance while driving high
+ */
+struct override_params {
+	struct override_param hs_disconnect;
+	struct override_param squelch_detector;
+	struct override_param hs_amplitude;
+	struct override_param preemphasis_duration;
+	struct override_param preemphasis_amplitude;
+	struct override_param hs_rise_fall_time;
+	struct override_param hs_crossover_voltage;
+	struct override_param hs_output_impedance;
+	struct override_param ls_fs_output_impedance;
+};
+
 /**
  * struct qcom_snps_hsphy - snps hs phy attributes
  *
@@ -87,6 +166,7 @@ struct qcom_snps_hsphy {
 	struct clk *ref_clk;
 	struct reset_control *phy_reset;
 	struct regulator_bulk_data vregs[SNPS_HS_NUM_VREGS];
+	struct override_params overrides;
 
 	bool phy_initialized;
 	enum phy_mode mode;
@@ -175,6 +255,7 @@ static int qcom_snps_hsphy_set_mode(struct phy *phy, enum phy_mode mode,
 static int qcom_snps_hsphy_init(struct phy *phy)
 {
 	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
+	struct override_params *or = &hsphy->overrides;
 	int ret;
 
 	dev_vdbg(&phy->dev, "%s(): Initializing SNPS HS phy\n", __func__);
@@ -222,6 +303,60 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL1,
 					VBUSVLDEXT0, VBUSVLDEXT0);
 
+	if (or->hs_disconnect.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X0,
+			HS_DISCONNECT_MASK,
+			or->hs_disconnect.value << HS_DISCONNECT_SHIFT);
+
+	if (or->squelch_detector.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X0,
+			SQUELCH_DETECTOR_MASK,
+			or->squelch_detector.value << SQUELCH_DETECTOR_SHIFT);
+
+	if (or->hs_amplitude.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X1,
+			HS_AMPLITUDE_MASK,
+			or->hs_amplitude.value << HS_AMPLITUDE_SHIFT);
+
+	if (or->preemphasis_duration.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X1,
+			PREEMPHASIS_DURATION_MASK,
+			or->preemphasis_duration.value << PREEMPHASIS_DURATION_SHIFT);
+
+	if (or->preemphasis_amplitude.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X1,
+			PREEMPHASIS_AMPLITUDE_MASK,
+			or->preemphasis_amplitude.value << PREEMPHASIS_AMPLITUDE_SHIFT);
+
+	if (or->hs_rise_fall_time.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X2,
+			HS_RISE_FALL_MASK,
+			or->hs_rise_fall_time.value << HS_RISE_FALL_SHIFT);
+
+	if (or->hs_crossover_voltage.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X2,
+			HS_CROSSOVER_VOLTAGE_MASK,
+			or->hs_crossover_voltage.value << HS_CROSSOVER_VOLTAGE_SHIFT);
+
+	if (or->hs_output_impedance.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X2,
+			HS_OUTPUT_IMPEDANCE_MASK,
+			or->hs_output_impedance.value << HS_OUTPUT_IMPEDANCE_SHIFT);
+
+	if (or->ls_fs_output_impedance.override)
+		qcom_snps_hsphy_write_mask(hsphy->base,
+			USB2_PHY_USB_PHY_HS_PHY_OVERRIDE_X3,
+			LS_FS_OUTPUT_IMPEDANCE_MASK,
+			or->ls_fs_output_impedance.value << LS_FS_OUTPUT_IMPEDANCE_SHIFT);
+
 	qcom_snps_hsphy_write_mask(hsphy->base,
 					USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON2,
 					VREGBYPASS, VREGBYPASS);
@@ -292,12 +427,15 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 	struct qcom_snps_hsphy *hsphy;
 	struct phy_provider *phy_provider;
 	struct phy *generic_phy;
+	struct override_params *or;
 	int ret, i;
 	int num;
+	u32 value;
 
 	hsphy = devm_kzalloc(dev, sizeof(*hsphy), GFP_KERNEL);
 	if (!hsphy)
 		return -ENOMEM;
+	or = &hsphy->overrides;
 
 	hsphy->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(hsphy->base))
@@ -329,6 +467,60 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	if (!of_property_read_u32(dev->of_node, "qcom,hs-disconnect",
+				  &value)) {
+		or->hs_disconnect.value = (u8)value;
+		or->hs_disconnect.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,squelch-detector",
+				  &value)) {
+		or->squelch_detector.value = (u8)value;
+		or->squelch_detector.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,hs-amplitude",
+				  &value)) {
+		or->hs_amplitude.value = (u8)value;
+		or->hs_amplitude.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,preemphasis-duration",
+				  &value)) {
+		or->preemphasis_duration.value = (u8)value;
+		or->preemphasis_duration.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,preemphasis-amplitude",
+				  &value)) {
+		or->preemphasis_amplitude.value = (u8)value;
+		or->preemphasis_amplitude.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,hs-rise-fall-time",
+				  &value)) {
+		or->hs_rise_fall_time.value = (u8)value;
+		or->hs_rise_fall_time.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,hs-crossover-voltage",
+				  &value)) {
+		or->hs_crossover_voltage.value = (u8)value;
+		or->hs_crossover_voltage.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,hs-output-impedance",
+				  &value)) {
+		or->hs_output_impedance.value = (u8)value;
+		or->hs_output_impedance.override = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,ls-fs-output-impedance",
+				  &value)) {
+		or->ls_fs_output_impedance.value = (u8)value;
+		or->ls_fs_output_impedance.override = true;
+	}
+
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 	/*
-- 
2.7.4