[PATCH 06/14] net: phy: ksz90x1: Handle ksz9131 LED errata

[Paul Barker]

On 27/10/2024 16:18, Marek Vasut wrote:
> On 10/24/24 5:24 PM, Paul Barker wrote:
>> Micrel KSZ9131 PHY LED behavior is not correct when configured in
>> Individual Mode, LED1 (Activity LED) is in the ON state when there is
>> no-link.
>>
>> Workaround this by setting bit 9 of register 0x1e after verifying that
>> the LED configuration is Individual Mode.
>>
>> This issue is described in KSZ9131RNX Silicon Errata DS80000693B [*]
>> and according to that it will not be corrected in a future silicon
>> revision.
>>
>> [*] https://ww1.microchip.com/downloads/en/DeviceDoc/KSZ9131RNX-Silicon-Errata-and-Data-Sheet-Clarification-80000863B.pdf
>>
>> Based on commit 0316c7e66bbd in the Linux kernel.
>>
>> Signed-off-by: Paul Barker <paul.barker.ct at bp.renesas.com>
>> ---
>>   drivers/net/phy/micrel_ksz90x1.c | 24 ++++++++++++++++++++++++
>>   1 file changed, 24 insertions(+)
>>
>> diff --git a/drivers/net/phy/micrel_ksz90x1.c b/drivers/net/phy/micrel_ksz90x1.c
>> index c48ae6e88f30..4f99b115a3c7 100644
>> --- a/drivers/net/phy/micrel_ksz90x1.c
>> +++ b/drivers/net/phy/micrel_ksz90x1.c
>> @@ -436,6 +436,26 @@ static int ksz9131_config_rgmii_delay(struct phy_device *phydev)
>>   	return ret;
>>   }
>>   
>> +/* Silicon Errata DS80000693B
>> + *
>> + * When LEDs are configured in Individual Mode, LED1 is ON in a no-link
>> + * condition. Workaround is to set register 0x1e, bit 9, this way LED1 behaves
>> + * according to the datasheet (off if there is no link).
>> + */
>> +static int ksz9131_led_errata(struct phy_device *phydev)
>> +{
>> +	int reg;
>> +
>> +	reg = phy_read_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, 0);
>> +	if (reg < 0)
>> +		return reg;
>> +
>> +	if (!(reg & BIT(4)))
> It would be good to have symbolic names for these BIT()s , please add 
> some #define ... macros .

I can add symbolic names for the values used above
(KSZ9131RN_COMMON_CTRL=0 and KSZ9131RN_COMMON_CTRL_LED_MODE=BIT(4)).

The arguments used in the following phy_set_bits() call are a bit
trickier - all the errata document says is "Register 0x1E (30d), bit 9
must be set to 1". The Linux kernel commit adding this workaround
doesn't have any symbolic names either.

Thanks,

-- 
Paul Barker
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