[v2] phy: exynos5-usbdrd: fix USB 2.0 HS PHY tuning values for Exynos7870

[PATCH v2] phy: exynos5-usbdrd: fix USB 2.0 HS PHY tuning values for Exynos7870

Posted by Łukasz Lebiedziński 2 months, 1 week ago

The existing PHYPARAM0 tuning values for Exynos7870 are incorrect,
causing the USB 2.0 PHY to fail high-speed negotiation and fall back
to full-speed (12Mbps) operation.

Fix TXVREFTUNE (transmitter voltage reference) from 14 to 3,
TXRESTUNE (transmitter impedance) from 3 to 2, and SQRXTUNE
(squelch threshold) from 6 to 5. Also explicitly set
TXPREEMPPULSETUNE to 0, which was previously missing from the
tuning table despite being included in the register mask.

All values are derived from the vendor kernel for the Samsung
Galaxy A6 (SM-A600FN), as no public hardware documentation is
available for the Exynos7870 USB DRD PHY. With these corrections,
the PHY successfully negotiates high-speed (480Mbps) operation.

Fixes: 588d5d20ca8d ("phy: exynos5-usbdrd: add exynos7870 USBDRD support")
Cc: stable@vger.kernel.org
Tested-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Łukasz Lebiedziński <kernel@lvkasz.us>
---
 drivers/phy/samsung/phy-exynos5-usbdrd.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
index 5a181cb4597e..8711a3b62c8e 100644
--- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
+++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
@@ -1958,13 +1958,14 @@ const struct exynos5_usbdrd_phy_tuning exynos7870_tunes_utmi_postinit[] = {
 			      PHYPARAM0_TXPREEMPAMPTUNE | PHYPARAM0_TXHSXVTUNE |
 			      PHYPARAM0_TXFSLSTUNE | PHYPARAM0_SQRXTUNE |
 			      PHYPARAM0_OTGTUNE | PHYPARAM0_COMPDISTUNE),
-			     (FIELD_PREP_CONST(PHYPARAM0_TXVREFTUNE, 14) |
+			     (FIELD_PREP_CONST(PHYPARAM0_TXVREFTUNE, 3) |
 			      FIELD_PREP_CONST(PHYPARAM0_TXRISETUNE, 1) |
-			      FIELD_PREP_CONST(PHYPARAM0_TXRESTUNE, 3) |
+			      FIELD_PREP_CONST(PHYPARAM0_TXRESTUNE, 2) |
+			      FIELD_PREP_CONST(PHYPARAM0_TXPREEMPPULSETUNE, 0) |
 			      FIELD_PREP_CONST(PHYPARAM0_TXPREEMPAMPTUNE, 0) |
 			      FIELD_PREP_CONST(PHYPARAM0_TXHSXVTUNE, 0) |
 			      FIELD_PREP_CONST(PHYPARAM0_TXFSLSTUNE, 3) |
-			      FIELD_PREP_CONST(PHYPARAM0_SQRXTUNE, 6) |
+			      FIELD_PREP_CONST(PHYPARAM0_SQRXTUNE, 5) |
 			      FIELD_PREP_CONST(PHYPARAM0_OTGTUNE, 2) |
 			      FIELD_PREP_CONST(PHYPARAM0_COMPDISTUNE, 3))),
 	PHY_TUNING_ENTRY_LAST
-- 
2.53.0

Re: [PATCH v2] phy: exynos5-usbdrd: fix USB 2.0 HS PHY tuning values for Exynos7870

Posted by Vinod Koul 1 month ago

On Mon, 06 Apr 2026 15:56:27 +0200, Łukasz Lebiedziński wrote:
> The existing PHYPARAM0 tuning values for Exynos7870 are incorrect,
> causing the USB 2.0 PHY to fail high-speed negotiation and fall back
> to full-speed (12Mbps) operation.
> 
> Fix TXVREFTUNE (transmitter voltage reference) from 14 to 3,
> TXRESTUNE (transmitter impedance) from 3 to 2, and SQRXTUNE
> (squelch threshold) from 6 to 5. Also explicitly set
> TXPREEMPPULSETUNE to 0, which was previously missing from the
> tuning table despite being included in the register mask.
> 
> [...]

Applied, thanks!

[1/1] phy: exynos5-usbdrd: fix USB 2.0 HS PHY tuning values for Exynos7870
      commit: 5a759b120e31aa3ed914d98b51eb1755235250f2

Best regards,
-- 
~Vinod

Re: [PATCH v2] phy: exynos5-usbdrd: fix USB 2.0 HS PHY tuning values for Exynos7870

Posted by Łukasz Lebiedziński 1 month, 3 weeks ago

On 4/6/26 15:56, Łukasz Lebiedziński wrote:
> The existing PHYPARAM0 tuning values for Exynos7870 are incorrect,
> causing the USB 2.0 PHY to fail high-speed negotiation and fall back
> to full-speed (12Mbps) operation.
> 
> Fix TXVREFTUNE (transmitter voltage reference) from 14 to 3,
> TXRESTUNE (transmitter impedance) from 3 to 2, and SQRXTUNE
> (squelch threshold) from 6 to 5. Also explicitly set
> TXPREEMPPULSETUNE to 0, which was previously missing from the
> tuning table despite being included in the register mask.
> 
> All values are derived from the vendor kernel for the Samsung
> Galaxy A6 (SM-A600FN), as no public hardware documentation is
> available for the Exynos7870 USB DRD PHY. With these corrections,
> the PHY successfully negotiates high-speed (480Mbps) operation.
> 
> Fixes: 588d5d20ca8d ("phy: exynos5-usbdrd: add exynos7870 USBDRD support")
> Cc: stable@vger.kernel.org
> Tested-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> Signed-off-by: Łukasz Lebiedziński <kernel@lvkasz.us>

Friendly ping.

I'd also like to mention that this patch was tested on two devices:
Samsung Galaxy A6 (SM-A600FN) by me and Samsung Galaxy J6 (SM-J600FN)
by Kaustabh Chakraborty <kauschluss@disroot.org>.


Regards,
Łukasz