Re: [PATCH v4 1/3] net: dsa: microchip: implement KSZ87xx Module 3 low-loss cable errata

[Marek Vasut <marex@nabladev.com>]

On 4/17/26 5:20 PM, Fidelio LAWSON wrote:
> On 4/17/26 16:35, Marek Vasut wrote:
>> On 4/17/26 2:44 PM, Fidelio Lawson wrote:
>>
>> [...]
>>
>>> @@ -1271,6 +1287,29 @@ int ksz8_w_phy(struct ksz_device *dev, u16 
>>> phy, u16 reg, u16 val)
>>>           if (ret)
>>>               return ret;
>>>           break;
>>> +    case PHY_REG_KSZ87XX_SHORT_CABLE:
>>> +        if (!ksz_is_ksz87xx(dev))
>>> +            return -EOPNOTSUPP;
>>> +        ret = ksz87xx_apply_low_loss_preset(dev, !!val);
>>> +        if (ret)
>>> +            return ret;
>>> +        break;
>>> +    case PHY_REG_KSZ87XX_LPF_BW:
>>> +        if (!ksz_is_ksz87xx(dev))
>>> +            return -EOPNOTSUPP;
>>> +        ret = ksz8_ind_write8(dev, TABLE_LINK_MD, 
>>> KSZ87XX_REG_PHY_LPF, (u8)val);
>>> +        if (ret)
>>> +            return ret;
>>> +        dev->lpf_bw = val;
>>> +        break;
>>> +    case PHY_REG_KSZ87XX_EQ_INIT:
>>> +        if (!ksz_is_ksz87xx(dev))
>>> +            return -EOPNOTSUPP;
>>> +        ret = ksz8_ind_write8(dev, TABLE_LINK_MD, 
>>> KSZ87XX_REG_DSP_EQ, (u8)val);
>> Do these values need some check, so they would be in the correct 
>> range(s) / in the correct bitfields before being written into those 
>> registers ?
> 
> Yes, I can add validation to ensure that only the documented bitfields 
> are accepted before writing the registers, (bits [7:6] for the LPF 
> bandwidth and bits [5:0] for the DSP EQ initial value).
Yes please, thank you !