phy: qualcomm: phy-qcom-eusb2-repeater: Don't zero-out registers

Zeroing out registers does not happen in the downstream kernel, and will
"tune" the repeater in surely unexpected ways since most registers don't
have a reset value of 0x0.

Stop doing that and instead just set the registers that are in the init
sequence (though long term I don't think there's actually PMIC-specific
init sequences, there's board specific tuning, but that's a story for
another day).

Fixes: 99a517a ("phy: qualcomm: phy-qcom-eusb2-repeater: Zero out untouched tuning regs")
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20250617-eusb2-repeater-tuning-v2-2-ed6c484f18ee@fairphone.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: lweiss-fairphone

drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c

@@ -37,32 +37,13 @@
 #define EUSB2_TUNE_EUSB_EQU		0x5A
 #define EUSB2_TUNE_EUSB_HS_COMP_CUR	0x5B
 
-enum eusb2_reg_layout {
-	TUNE_EUSB_HS_COMP_CUR,
-	TUNE_EUSB_EQU,
-	TUNE_EUSB_SLEW,
-	TUNE_USB2_HS_COMP_CUR,
-	TUNE_USB2_PREEM,
-	TUNE_USB2_EQU,
-	TUNE_USB2_SLEW,
-	TUNE_SQUELCH_U,
-	TUNE_HSDISC,
-	TUNE_RES_FSDIF,
-	TUNE_IUSB2,
-	TUNE_USB2_CROSSOVER,
-	NUM_TUNE_FIELDS,
-
-	FORCE_VAL_5 = NUM_TUNE_FIELDS,
-	FORCE_EN_5,
-
-	EN_CTL1,
-
-	RPTR_STATUS,
-	LAYOUT_SIZE,
+struct eusb2_repeater_init_tbl_reg {
+	unsigned int reg;
+	unsigned int value;
 };
 
 struct eusb2_repeater_cfg {
-	const u32 *init_tbl;
+	const struct eusb2_repeater_init_tbl_reg *init_tbl;
 	int init_tbl_num;
 	const char * const *vreg_list;
 	int num_vregs;
@@ -82,16 +63,16 @@ static const char * const pm8550b_vreg_l[] = {
 	"vdd18", "vdd3",
 };
 
-static const u32 pm8550b_init_tbl[NUM_TUNE_FIELDS] = {
-	[TUNE_IUSB2] = 0x8,
-	[TUNE_SQUELCH_U] = 0x3,
-	[TUNE_USB2_PREEM] = 0x5,
+static const struct eusb2_repeater_init_tbl_reg pm8550b_init_tbl[] = {
+	{ EUSB2_TUNE_IUSB2, 0x8 },
+	{ EUSB2_TUNE_SQUELCH_U, 0x3 },
+	{ EUSB2_TUNE_USB2_PREEM, 0x5 },
 };
 
-static const u32 smb2360_init_tbl[NUM_TUNE_FIELDS] = {
-	[TUNE_IUSB2] = 0x5,
-	[TUNE_SQUELCH_U] = 0x3,
-	[TUNE_USB2_PREEM] = 0x2,
+static const struct eusb2_repeater_init_tbl_reg smb2360_init_tbl[] = {
+	{ EUSB2_TUNE_IUSB2, 0x5 },
+	{ EUSB2_TUNE_SQUELCH_U, 0x3 },
+	{ EUSB2_TUNE_USB2_PREEM, 0x2 },
 };
 
 static const struct eusb2_repeater_cfg pm8550b_eusb2_cfg = {
@@ -129,39 +110,35 @@ static int eusb2_repeater_init(struct phy *phy)
 	struct eusb2_repeater *rptr = phy_get_drvdata(phy);
 	struct device_node *np = rptr->dev->of_node;
 	struct regmap *regmap = rptr->regmap;
-	const u32 *init_tbl = rptr->cfg->init_tbl;
-	u8 tune_usb2_preem = init_tbl[TUNE_USB2_PREEM];
-	u8 tune_hsdisc = init_tbl[TUNE_HSDISC];
-	u8 tune_iusb2 = init_tbl[TUNE_IUSB2];
 	u32 base = rptr->base;
-	u32 val;
+	u32 poll_val;
 	int ret;
-
-	of_property_read_u8(np, "qcom,tune-usb2-amplitude", &tune_iusb2);
-	of_property_read_u8(np, "qcom,tune-usb2-disc-thres", &tune_hsdisc);
-	of_property_read_u8(np, "qcom,tune-usb2-preem", &tune_usb2_preem);
+	u8 val;
 
 	ret = regulator_bulk_enable(rptr->cfg->num_vregs, rptr->vregs);
 	if (ret)
 		return ret;
 
 	regmap_write(regmap, base + EUSB2_EN_CTL1, EUSB2_RPTR_EN);
 
-	regmap_write(regmap, base + EUSB2_TUNE_EUSB_HS_COMP_CUR, init_tbl[TUNE_EUSB_HS_COMP_CUR]);
-	regmap_write(regmap, base + EUSB2_TUNE_EUSB_EQU, init_tbl[TUNE_EUSB_EQU]);
-	regmap_write(regmap, base + EUSB2_TUNE_EUSB_SLEW, init_tbl[TUNE_EUSB_SLEW]);
-	regmap_write(regmap, base + EUSB2_TUNE_USB2_HS_COMP_CUR, init_tbl[TUNE_USB2_HS_COMP_CUR]);
-	regmap_write(regmap, base + EUSB2_TUNE_USB2_EQU, init_tbl[TUNE_USB2_EQU]);
-	regmap_write(regmap, base + EUSB2_TUNE_USB2_SLEW, init_tbl[TUNE_USB2_SLEW]);
-	regmap_write(regmap, base + EUSB2_TUNE_SQUELCH_U, init_tbl[TUNE_SQUELCH_U]);
-	regmap_write(regmap, base + EUSB2_TUNE_RES_FSDIF, init_tbl[TUNE_RES_FSDIF]);
-	regmap_write(regmap, base + EUSB2_TUNE_USB2_CROSSOVER, init_tbl[TUNE_USB2_CROSSOVER]);
-
-	regmap_write(regmap, base + EUSB2_TUNE_USB2_PREEM, tune_usb2_preem);
-	regmap_write(regmap, base + EUSB2_TUNE_HSDISC, tune_hsdisc);
-	regmap_write(regmap, base + EUSB2_TUNE_IUSB2, tune_iusb2);
-
-	ret = regmap_read_poll_timeout(regmap, base + EUSB2_RPTR_STATUS, val, val & RPTR_OK, 10, 5);
+	/* Write registers from init table */
+	for (int i = 0; i < rptr->cfg->init_tbl_num; i++)
+		regmap_write(regmap, base + rptr->cfg->init_tbl[i].reg,
+			     rptr->cfg->init_tbl[i].value);
+
+	/* Override registers from devicetree values */
+	if (!of_property_read_u8(np, "qcom,tune-usb2-amplitude", &val))
+		regmap_write(regmap, base + EUSB2_TUNE_USB2_PREEM, val);
+
+	if (!of_property_read_u8(np, "qcom,tune-usb2-disc-thres", &val))
+		regmap_write(regmap, base + EUSB2_TUNE_HSDISC, val);
+
+	if (!of_property_read_u8(np, "qcom,tune-usb2-preem", &val))
+		regmap_write(regmap, base + EUSB2_TUNE_IUSB2, val);
+
+	/* Wait for status OK */
+	ret = regmap_read_poll_timeout(regmap, base + EUSB2_RPTR_STATUS, poll_val,
+				       poll_val & RPTR_OK, 10, 5);
 	if (ret)
 		dev_err(rptr->dev, "initialization timed-out\n");