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SubjectRe: [PATCH] dp83640: Ensure against premature access to PHY registers after reset
From
From: Andrew Lunn <andrew@lunn.ch>
Date: Fri, 6 Apr 2018 16:14:10 +0200

> On Fri, Apr 06, 2018 at 04:05:40PM +0200, Esben Haabendal wrote:
>> From: Esben Haabendal <eha@deif.com>
>>
>> Signed-off-by: Esben Haabendal <eha@deif.com>
>> ---
>> drivers/net/phy/dp83640.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/net/phy/dp83640.c b/drivers/net/phy/dp83640.c
>> index 654f42d00092..48403170096a 100644
>> --- a/drivers/net/phy/dp83640.c
>> +++ b/drivers/net/phy/dp83640.c
>> @@ -1207,6 +1207,22 @@ static void dp83640_remove(struct phy_device *phydev)
>> kfree(dp83640);
>> }
>>
>> +static int dp83640_soft_reset(struct phy_device *phydev)
>> +{
>> + int ret;
>> +
>> + ret = genphy_soft_reset(phydev);
>> + if (ret < 0)
>> + return ret;
>> +
>> + /* From DP83640 datasheet: "Software driver code must wait 3 us
>> + * following a software reset before allowing further serial MII
>> + * operations with the DP83640." */
>> + udelay(3);
>
> Hi Esben
>
> The accuracy of udelay() is not guaranteed. So you probably want to be
> a bit pessimistic, and use 10.

Agreed.

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