[PATCH for 6.6 1/2] ARM: dts: am335x-bone-common: Increase MDIO reset deassert time

[PATCH for 6.6 1/2] ARM: dts: am335x-bone-common: Increase MDIO reset deassert time

[Nobuhiro Iwamatsu]

From: Colin Foster <colin.foster@in-advantage.com>

commit b9bf5612610aa7e38d58fee16f489814db251c01 upstream.

Prior to commit df16c1c51d81 ("net: phy: mdio_device: Reset device only
when necessary") MDIO reset deasserts were performed twice during boot.
Now that the second deassert is no longer performed, device probe
failures happen due to the change in timing with the following error
message:

SMSC LAN8710/LAN8720: probe of 4a101000.mdio:00 failed with error -5

Restore the original effective timing, which resolves the probe
failures.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Link: https://lore.kernel.org/r/20240531183817.2698445-1-colin.foster@in-advantage.com
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
---
 arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
index 96451c8a815c..4867ff28c97e 100644
--- a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
+++ b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
@@ -385,7 +385,7 @@
 		/* Support GPIO reset on revision C3 boards */
 		reset-gpios = <&gpio1 8 GPIO_ACTIVE_LOW>;
 		reset-assert-us = <300>;
-		reset-deassert-us = <6500>;
+		reset-deassert-us = <13000>;
 	};
 };
 
-- 
2.25.1

[PATCH for 6.6 2/2] ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms

[Nobuhiro Iwamatsu]

From: Geert Uytterhoeven <geert+renesas@glider.be>

commit 929d8490f8790164f5f63671c1c58d6c50411cb2 upstream.

Commit b9bf5612610aa7e3 ("ARM: dts: am335x-bone-common: Increase MDIO
reset deassert time") already increased the MDIO reset deassert delay
from 6.5 to 13 ms, but this may still cause Ethernet PHY probe failures:

    SMSC LAN8710/LAN8720 4a101000.mdio:00: probe with driver SMSC LAN8710/LAN8720 failed with error -5

On BeagleBone Black Rev. C3, ETH_RESETn is controlled by an open-drain
AND gate.  It is pulled high by a 10K resistor, and has a 4.7µF
capacitor to ground, giving an RC time constant of 47ms.  As it takes
0.7RC to charge the capacitor above the threshold voltage of a CMOS
input (VDD/2), the delay should be at least 33ms.  Considering the
typical tolerance of 20% on capacitors, 40ms would be safer.  Add an
additional safety margin and settle for 50ms.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/9002a58daa1b2983f39815b748ee9d2f8dcc4829.1730366936.git.geert+renesas@glider.be
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
---
 arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
index 4867ff28c97e..27e73e745e25 100644
--- a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
+++ b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
@@ -385,7 +385,7 @@
 		/* Support GPIO reset on revision C3 boards */
 		reset-gpios = <&gpio1 8 GPIO_ACTIVE_LOW>;
 		reset-assert-us = <300>;
-		reset-deassert-us = <13000>;
+		reset-deassert-us = <50000>;
 	};
 };
 
-- 
2.25.1

Re: [PATCH for 6.6 1/2] ARM: dts: am335x-bone-common: Increase MDIO reset deassert time

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: b9bf5612610aa7e38d58fee16f489814db251c01

WARNING: Author mismatch between patch and upstream commit:
Backport author: Nobuhiro Iwamatsu<nobuhiro1.iwamatsu@toshiba.co.jp>
Commit author: Colin Foster<colin.foster@in-advantage.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)

Note: The patch differs from the upstream commit:
---
1:  b9bf5612610aa ! 1:  b61bb04ce6bad ARM: dts: am335x-bone-common: Increase MDIO reset deassert time
    @@ Metadata
      ## Commit message ##
         ARM: dts: am335x-bone-common: Increase MDIO reset deassert time
     
    +    commit b9bf5612610aa7e38d58fee16f489814db251c01 upstream.
    +
         Prior to commit df16c1c51d81 ("net: phy: mdio_device: Reset device only
         when necessary") MDIO reset deasserts were performed twice during boot.
         Now that the second deassert is no longer performed, device probe
    @@ Commit message
         Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
         Link: https://lore.kernel.org/r/20240531183817.2698445-1-colin.foster@in-advantage.com
         Signed-off-by: Kevin Hilman <khilman@baylibre.com>
    +    Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
     
      ## arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi ##
     @@ arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi: ethphy0: ethernet-phy@0 {
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.6.y        |  Success    |  Success   |

Re: [PATCH for 6.6 2/2] ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 929d8490f8790164f5f63671c1c58d6c50411cb2

WARNING: Author mismatch between patch and upstream commit:
Backport author: Nobuhiro Iwamatsu<nobuhiro1.iwamatsu@toshiba.co.jp>
Commit author: Geert Uytterhoeven<geert+renesas@glider.be>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.12.y | Not found

Note: The patch differs from the upstream commit:
---
1:  929d8490f8790 ! 1:  c4225ee1fae71 ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms
    @@ Metadata
      ## Commit message ##
         ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms
     
    +    commit 929d8490f8790164f5f63671c1c58d6c50411cb2 upstream.
    +
         Commit b9bf5612610aa7e3 ("ARM: dts: am335x-bone-common: Increase MDIO
         reset deassert time") already increased the MDIO reset deassert delay
         from 6.5 to 13 ms, but this may still cause Ethernet PHY probe failures:
    @@ Commit message
         Reviewed-by: Roger Quadros <rogerq@kernel.org>
         Link: https://lore.kernel.org/r/9002a58daa1b2983f39815b748ee9d2f8dcc4829.1730366936.git.geert+renesas@glider.be
         Signed-off-by: Kevin Hilman <khilman@baylibre.com>
    +    Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
     
      ## arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi ##
     @@ arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi: ethphy0: ethernet-phy@0 {
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.12.y       |  Success    |  Success   |