[U-Boot] [PATCH] drivers: net: phy: Ignore PHY ID 0 during PHY probing

[Alex Marginean]

Hi Joe,

On 7/2/2019 12:17 AM, Joe Hershberger wrote:
> On Wed, Jun 19, 2019 at 4:07 AM Alexandru Marginean
> <alexandru.marginean at nxp.com> wrote:
>>
>> Current code fails to probe some C45 PHYs that also respond to C22 reads.
>> This is the case for PHYs like Aquantia AQR112, Marvell 88X2242 (as
>> previously posted on the u-boot list).
>> If the PHY ID reads all 0s just ignore it and try the next devad.
>>
>> Signed-off-by: Alex Marginean <alexm.osslist at gmail.com>
>> ---
>>   drivers/net/phy/phy.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index c1c1af9abd..7ccbc4d9da 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -727,6 +727,15 @@ static struct phy_device *create_phy_by_mask(struct mii_dev *bus,
>>          while (phy_mask) {
>>                  int addr = ffs(phy_mask) - 1;
>>                  int r = get_phy_id(bus, addr, devad, &phy_id);
>> +
>> +               /* If the PHY ID is flat 0 we ignore it.  There are C45 PHYs
> 
> Agreed on the format.
> 
>> +                * that return all 0s for C22 reads (like Aquantia AQR112) and
>> +                * there are C22 PHYs that return all 0s for C45 reads (like
>> +                * Atheros AR8035).
>> +                */
>> +               if (phy_id == 0)
>> +                       return NULL;
> 
> As for continue or return, this should probably check that phy_id == 0
> and r == 0, right?

Right, in case the read over MDIO returns an error code for the missing
PHY we want to continue the loop.  I'll fix this.

Thank you!
Alex

> 
>> +
>>                  /* If the PHY ID is mostly f's, we didn't find anything */
>>                  if (r == 0 && (phy_id & 0x1fffffff) != 0x1fffffff) {
>>                          is_c45 = (devad == MDIO_DEVAD_NONE) ? false : true;
>> --
>> 2.17.1
>>
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