phy: qcom-qusb2: Add QUSB2 PHYs support for sdm845

There are two QUSB2 PHYs present on sdm845. In order
to improve eye diagram for both the PHYs some parameters
need to be changed. Provide device tree properties to
override these from board specific device tree files.

Signed-off-by: Manu Gautam <[e-mail]>
Reviewed-by: Douglas Anderson <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/qualcomm/phy-qcom-qusb2.c

···
 #include <linux/reset.h>
 #include <linux/slab.h>
 
+#include <dt-bindings/phy/phy-qcom-qusb2.h>
+
 #define QUSB2PHY_PLL_TEST		0x04
 #define CLK_REF_SEL			BIT(7)
 
···
 #define CORE_PLL_EN_FROM_RESET			BIT(4)
 #define CORE_RESET				BIT(5)
 #define CORE_RESET_MUX				BIT(6)
+
+/* QUSB2PHY_IMP_CTRL1 register bits */
+#define IMP_RES_OFFSET_MASK			GENMASK(5, 0)
+#define IMP_RES_OFFSET_SHIFT			0x0
+
+/* QUSB2PHY_PORT_TUNE1 register bits */
+#define HSTX_TRIM_MASK				GENMASK(7, 4)
+#define HSTX_TRIM_SHIFT				0x4
+#define PREEMPH_WIDTH_HALF_BIT			BIT(2)
+#define PREEMPHASIS_EN_MASK			GENMASK(1, 0)
+#define PREEMPHASIS_EN_SHIFT			0x0
 
 #define QUSB2PHY_PLL_ANALOG_CONTROLS_TWO	0x04
 #define QUSB2PHY_PLL_CLOCK_INVERTERS		0x18c
···
 	QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_PWR_CTRL, 0x00),
 };
 
-static const unsigned int qusb2_v2_regs_layout[] = {
+static const unsigned int sdm845_regs_layout[] = {
 	[QUSB2PHY_PLL_CORE_INPUT_OVERRIDE] = 0xa8,
 	[QUSB2PHY_PLL_STATUS]		= 0x1a0,
 	[QUSB2PHY_PORT_TUNE1]		= 0x240,
···
 	[QUSB2PHY_INTR_CTRL]		= 0x230,
 };
 
-static const struct qusb2_phy_init_tbl qusb2_v2_init_tbl[] = {
+static const struct qusb2_phy_init_tbl sdm845_init_tbl[] = {
 	QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_ANALOG_CONTROLS_TWO, 0x03),
 	QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_CLOCK_INVERTERS, 0x7c),
 	QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_CMODE, 0x80),
···
 	.autoresume_en	 = BIT(3),
 };
 
-static const struct qusb2_phy_cfg qusb2_v2_phy_cfg = {
-	.tbl		= qusb2_v2_init_tbl,
-	.tbl_num	= ARRAY_SIZE(qusb2_v2_init_tbl),
-	.regs		= qusb2_v2_regs_layout,
+static const struct qusb2_phy_cfg sdm845_phy_cfg = {
+	.tbl		= sdm845_init_tbl,
+	.tbl_num	= ARRAY_SIZE(sdm845_init_tbl),
+	.regs		= sdm845_regs_layout,
 
 	.disable_ctrl	= (PWR_CTRL1_VREF_SUPPLY_TRIM | PWR_CTRL1_CLAMP_N_EN |
 			   POWER_DOWN),
···
  * @tcsr: TCSR syscon register map
  * @cell: nvmem cell containing phy tuning value
  *
+ * @override_imp_res_offset: PHY should use different rescode offset
+ * @imp_res_offset_value: rescode offset to be updated in IMP_CTRL1 register
+ * @override_hstx_trim: PHY should use different HSTX o/p current value
+ * @hstx_trim_value: HSTX_TRIM value to be updated in TUNE1 register
+ * @override_preemphasis: PHY should use different pre-amphasis amplitude
+ * @preemphasis_level: Amplitude Pre-Emphasis to be updated in TUNE1 register
+ * @override_preemphasis_width: PHY should use different pre-emphasis duration
+ * @preemphasis_width: half/full-width Pre-Emphasis updated via TUNE1
+ *
  * @cfg: phy config data
  * @has_se_clk_scheme: indicate if PHY has single-ended ref clock scheme
  * @phy_initialized: indicate if PHY has been initialized
···
 	struct regmap *tcsr;
 	struct nvmem_cell *cell;
 
+	bool override_imp_res_offset;
+	u8 imp_res_offset_value;
+	bool override_hstx_trim;
+	u8 hstx_trim_value;
+	bool override_preemphasis;
+	u8 preemphasis_level;
+	bool override_preemphasis_width;
+	u8 preemphasis_width;
+
 	const struct qusb2_phy_cfg *cfg;
 	bool has_se_clk_scheme;
 	bool phy_initialized;
 	enum phy_mode mode;
 };
+
+static inline void qusb2_write_mask(void __iomem *base, u32 offset,
+				    u32 val, u32 mask)
+{
+	u32 reg;
+
+	reg = readl(base + offset);
+	reg &= ~mask;
+	reg |= val & mask;
+	writel(reg, base + offset);
+
+	/* Ensure above write is completed */
+	readl(base + offset);
+}
 
 static inline void qusb2_setbits(void __iomem *base, u32 offset, u32 val)
 {
···
 			writel(tbl[i].val, base + regs[tbl[i].offset]);
 		else
 			writel(tbl[i].val, base + tbl[i].offset);
+	}
+}
+
+/*
+ * Update board specific PHY tuning override values if specified from
+ * device tree.
+ */
+static void qusb2_phy_override_phy_params(struct qusb2_phy *qphy)
+{
+	const struct qusb2_phy_cfg *cfg = qphy->cfg;
+
+	if (qphy->override_imp_res_offset)
+		qusb2_write_mask(qphy->base, QUSB2PHY_IMP_CTRL1,
+			     qphy->imp_res_offset_value << IMP_RES_OFFSET_SHIFT,
+			     IMP_RES_OFFSET_MASK);
+
+	if (qphy->override_hstx_trim)
+		qusb2_write_mask(qphy->base, cfg->regs[QUSB2PHY_PORT_TUNE1],
+				 qphy->hstx_trim_value << HSTX_TRIM_SHIFT,
+				 HSTX_TRIM_MASK);
+
+	if (qphy->override_preemphasis)
+		qusb2_write_mask(qphy->base, cfg->regs[QUSB2PHY_PORT_TUNE1],
+				qphy->preemphasis_level << PREEMPHASIS_EN_SHIFT,
+				PREEMPHASIS_EN_MASK);
+
+	if (qphy->override_preemphasis_width) {
+		if (qphy->preemphasis_width ==
+		    QUSB2_V2_PREEMPHASIS_WIDTH_HALF_BIT)
+			qusb2_setbits(qphy->base,
+				      cfg->regs[QUSB2PHY_PORT_TUNE1],
+				      PREEMPH_WIDTH_HALF_BIT);
+		else
+			qusb2_clrbits(qphy->base,
+				      cfg->regs[QUSB2PHY_PORT_TUNE1],
+				      PREEMPH_WIDTH_HALF_BIT);
 	}
 }
 
···
 	qcom_qusb2_phy_configure(qphy->base, cfg->regs, cfg->tbl,
 				 cfg->tbl_num);
 
+	/* Override board specific PHY tuning values */
+	qusb2_phy_override_phy_params(qphy);
+
 	/* Set efuse value for tuning the PHY */
 	qusb2_phy_set_tune2_param(qphy);
 
···
 		.compatible	= "qcom,msm8996-qusb2-phy",
 		.data		= &msm8996_phy_cfg,
 	}, {
-		.compatible	= "qcom,qusb2-v2-phy",
-		.data		= &qusb2_v2_phy_cfg,
+		.compatible	= "qcom,sdm845-qusb2-phy",
+		.data		= &sdm845_phy_cfg,
 	},
 	{ },
 };
···
 	struct resource *res;
 	int ret, i;
 	int num;
+	u32 value;
 
 	qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
 	if (!qphy)
···
 		qphy->cell = NULL;
 		dev_dbg(dev, "failed to lookup tune2 hstx trim value\n");
 	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,imp-res-offset-value",
+				  &value)) {
+		qphy->imp_res_offset_value = (u8)value;
+		qphy->override_imp_res_offset = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,hstx-trim-value",
+				  &value)) {
+		qphy->hstx_trim_value = (u8)value;
+		qphy->override_hstx_trim = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,preemphasis-level",
+				     &value)) {
+		qphy->preemphasis_level = (u8)value;
+		qphy->override_preemphasis = true;
+	}
+
+	if (!of_property_read_u32(dev->of_node, "qcom,preemphasis-width",
+				     &value)) {
+		qphy->preemphasis_width = (u8)value;
+		qphy->override_preemphasis_width = true;
+	}
+
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 	/*