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

[Fidelio LAWSON]

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).