netdev - Re: [PATCH 2/3] net:phy:dp83867: increase SGMII autoneg timer duration

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Date:   Fri, 24 May 2019 19:24:08 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Max Uvarov <muvarov@...il.com>, netdev@...r.kernel.org
Cc:     andrew@...n.ch, f.fainelli@...il.com, davem@...emloft.net
Subject: Re: [PATCH 2/3] net:phy:dp83867: increase SGMII autoneg timer
 duration

On 24.05.2019 12:25, Max Uvarov wrote:
> After reset SGMII Autoneg timer is set to 2us (bits 6 and 5 are 01).
> That us not enough to finalize autonegatiation on some devices.
> Increase this timer duration to maximum supported 16ms.
> 
> Signed-off-by: Max Uvarov <muvarov@...il.com>
> ---
>  drivers/net/phy/dp83867.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
> index afd31c516cc7..66b0a09ad094 100644
> --- a/drivers/net/phy/dp83867.c
> +++ b/drivers/net/phy/dp83867.c
> @@ -297,6 +297,19 @@ static int dp83867_config_init(struct phy_device *phydev)
>  			WARN_ONCE(1, "dp83867: err DP83867_10M_SGMII_CFG\n");
>  			return ret;
>  		}
> +
> +		/* After reset SGMII Autoneg timer is set to 2us (bits 6 and 5
> +		 * are 01). That us not enough to finalize autoneg on some
> +		 * devices. Increase this timer duration to maximum 16ms.
> +		 */
In the public datasheet the bits are described as reserved. However, based on
the value, I suppose it's not a timer value but the timer resolution.

> +		val = phy_read_mmd(phydev, DP83867_DEVADDR, DP83867_CFG4);
> +		val &= ~(BIT(5) | BIT(6));
> +		ret = phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_CFG4, val);
> +		if (ret) {
> +			WARN_ONCE(1, "dp83867: error config sgmii auto-neg timer\n");
> +			return ret;

Same comment as for patch 1.

> +		}
> +
>  	}
>  
>  	/* Enable Interrupt output INT_OE in CFG3 register */
>