[PATCH v2 0/2] Fix tuning on eUSB2 repeater

[PATCH v2 0/2] Fix tuning on eUSB2 repeater

[Luca Weiss]

Update the dt-bindings to remove the 'default' tuning values, since they
depend on the PMIC and are not guaranteed to be the same.

And add a fix into the driver to not zero-out all tuning registers if
they are not specified in the "init sequence", since zero is not the
reset value for most parameter and will lead to very unexpected tuning.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
Changes in v2:
- Fix wrong parameter used for refactored init tables
- Also drop "enum eusb2_reg_layout" completely since it's not used for
  anything now
- Use unsigned int instead of u8 in struct eusb2_repeater_init_tbl_reg
- Pick up tags
- Link to v1: https://lore.kernel.org/r/20250616-eusb2-repeater-tuning-v1-0-9457ff0fbf75@fairphone.com

---
Luca Weiss (2):
      dt-bindings: phy: qcom,snps-eusb2-repeater: Remove default tuning values
      phy: qualcomm: phy-qcom-eusb2-repeater: Don't zero-out registers

 .../bindings/phy/qcom,snps-eusb2-repeater.yaml     |  3 -
 drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c     | 83 ++++++++--------------
 2 files changed, 30 insertions(+), 56 deletions(-)
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250616-eusb2-repeater-tuning-f56331c6b1fa

Best regards,
-- 
Luca Weiss <luca.weiss@fairphone.com>

[PATCH v2 1/2] dt-bindings: phy: qcom,snps-eusb2-repeater: Remove default tuning values

[Luca Weiss]

The reset default tuning value depends on the PMIC, so remove them from
the doc since they're not accurate for all PMICs.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml b/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml
index d16a543a784887eabc69faae2233057c4554be31..27f064a71c9fb8cb60e8333fb285f0510a4af94f 100644
--- a/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml
+++ b/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml
@@ -39,21 +39,18 @@ properties:
     description: High-Speed disconnect threshold
     minimum: 0
     maximum: 7
-    default: 0
 
   qcom,tune-usb2-amplitude:
     $ref: /schemas/types.yaml#/definitions/uint8
     description: High-Speed transmit amplitude
     minimum: 0
     maximum: 15
-    default: 8
 
   qcom,tune-usb2-preem:
     $ref: /schemas/types.yaml#/definitions/uint8
     description: High-Speed TX pre-emphasis tuning
     minimum: 0
     maximum: 7
-    default: 5
 
 required:
   - compatible

-- 
2.49.0

Re: [PATCH v2 1/2] dt-bindings: phy: qcom,snps-eusb2-repeater: Remove default tuning values

[Rob Herring (Arm)]

On Tue, 17 Jun 2025 10:26:35 +0200, Luca Weiss wrote:
> The reset default tuning value depends on the PMIC, so remove them from
> the doc since they're not accurate for all PMICs.
> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>  Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml | 3 ---
>  1 file changed, 3 deletions(-)
> 

Acked-by: Rob Herring (Arm) <robh@kernel.org>

[PATCH v2 2/2] phy: qualcomm: phy-qcom-eusb2-repeater: Don't zero-out registers

[Luca Weiss]

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: 99a517a582fc ("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>
---
 drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c | 83 ++++++++++----------------
 1 file changed, 30 insertions(+), 53 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c b/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c
index 6bd1b3c75c779d2db2744703262e132cc439f76e..d7493c2294ef23e37e484019a49ddf7b3d6a6a46 100644
--- a/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c
+++ b/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 = {
@@ -129,17 +110,10 @@ 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)
@@ -147,21 +121,24 @@ static int eusb2_repeater_init(struct phy *phy)
 
 	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]);
+	/* 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);
 
-	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);
+	/* 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);
 
-	ret = regmap_read_poll_timeout(regmap, base + EUSB2_RPTR_STATUS, val, val & RPTR_OK, 10, 5);
+	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");
 

-- 
2.49.0

Re: [PATCH v2 2/2] phy: qualcomm: phy-qcom-eusb2-repeater: Don't zero-out registers

[Abel Vesa]

On 25-06-17 10:26:36, Luca Weiss wrote:
> 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: 99a517a582fc ("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: Abel Vesa <abel.vesa@linaro.org>

Re: [PATCH v2 2/2] phy: qualcomm: phy-qcom-eusb2-repeater: Don't zero-out registers

[Dmitry Baryshkov]

On Tue, Jun 17, 2025 at 10:26:36AM +0200, Luca Weiss wrote:
> 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: 99a517a582fc ("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>
> ---
>  drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c | 83 ++++++++++----------------
>  1 file changed, 30 insertions(+), 53 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry

Re: (subset) [PATCH v2 0/2] Fix tuning on eUSB2 repeater

[Vinod Koul]

On Tue, 17 Jun 2025 10:26:34 +0200, Luca Weiss wrote:
> Update the dt-bindings to remove the 'default' tuning values, since they
> depend on the PMIC and are not guaranteed to be the same.
> 
> And add a fix into the driver to not zero-out all tuning registers if
> they are not specified in the "init sequence", since zero is not the
> reset value for most parameter and will lead to very unexpected tuning.
> 
> [...]

Applied, thanks!

[1/2] dt-bindings: phy: qcom,snps-eusb2-repeater: Remove default tuning values
      commit: db9f3e3ff9347a233a17eadefae9c1b29ec8f3ed

Best regards,
-- 
~Vinod