[PATCH net v3] net: phy: c45-tjaxx: add delay between MDIO write and read in soft_reset

[PATCH net v3] net: phy: c45-tjaxx: add delay between MDIO write and read in soft_reset

[Milos Reljin]

In application note (AN13663) for TJA1120, on page 30, there's a figure
with average PHY startup timing values following software reset.
The time it takes for SMI to become operational after software reset
ranges roughly from 500 us to 1500 us.

This commit adds 2000 us delay after MDIO write which triggers software
reset. Without this delay, soft_reset function returns an error and
prevents successful PHY init.

Cc: stable@vger.kernel.org
Fixes: b050f2f15e04 ("phy: nxp-c45: add driver for tja1103")
Signed-off-by: Milos Reljin <milos_reljin@outlook.com>
---
Changes in v3:
 - Added Fixes and Cc tags, net tree indicator in Subject.

Changes in v2:
 - Updated commit message to clear up where the delay value comes from.
 - Delay added with usleep_range instead of changing sleep_before_read
   parameter of phy_read_mmd_poll_timeout to avoid excessive delay.
---
 drivers/net/phy/nxp-c45-tja11xx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/phy/nxp-c45-tja11xx.c b/drivers/net/phy/nxp-c45-tja11xx.c
index ade544bc007d..872e582b7e83 100644
--- a/drivers/net/phy/nxp-c45-tja11xx.c
+++ b/drivers/net/phy/nxp-c45-tja11xx.c
@@ -1297,6 +1297,8 @@ static int nxp_c45_soft_reset(struct phy_device *phydev)
 	if (ret)
 		return ret;
 
+	usleep_range(2000, 2050);
+
 	return phy_read_mmd_poll_timeout(phydev, MDIO_MMD_VEND1,
 					 VEND1_DEVICE_CONTROL, ret,
 					 !(ret & DEVICE_CONTROL_RESET), 20000,
-- 
2.34.1

Re: [PATCH net v3] net: phy: c45-tjaxx: add delay between MDIO write and read in soft_reset

[Andrew Lunn]

On Fri, Jan 24, 2025 at 10:41:02AM +0000, Milos Reljin wrote:
> In application note (AN13663) for TJA1120, on page 30, there's a figure
> with average PHY startup timing values following software reset.
> The time it takes for SMI to become operational after software reset
> ranges roughly from 500 us to 1500 us.
> 
> This commit adds 2000 us delay after MDIO write which triggers software
> reset. Without this delay, soft_reset function returns an error and
> prevents successful PHY init.
> 
> Cc: stable@vger.kernel.org
> Fixes: b050f2f15e04 ("phy: nxp-c45: add driver for tja1103")
> Signed-off-by: Milos Reljin <milos_reljin@outlook.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH net v3] net: phy: c45-tjaxx: add delay between MDIO write and read in soft_reset

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 24 Jan 2025 10:41:02 +0000 you wrote:
> In application note (AN13663) for TJA1120, on page 30, there's a figure
> with average PHY startup timing values following software reset.
> The time it takes for SMI to become operational after software reset
> ranges roughly from 500 us to 1500 us.
> 
> This commit adds 2000 us delay after MDIO write which triggers software
> reset. Without this delay, soft_reset function returns an error and
> prevents successful PHY init.
> 
> [...]

Here is the summary with links:
  - [net,v3] net: phy: c45-tjaxx: add delay between MDIO write and read in soft_reset
    https://git.kernel.org/netdev/net/c/bd1bbab71760

You are awesome, thank you!
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