Re: [PATCH RESEND net-next v2] net: phy: Add c45_phy_ids sysfs directory entry

["Yajun Deng" <yajun.deng@linux.dev>]

June 12, 2025 at 11:31 PM, "Andrew Lunn" <andrew@lunn.ch> wrote:



> 
> > 
> > +#define MMD_INDICES \
> > 
> >  + _(1) _(2) _(3) _(4) _(5) _(6) _(7) _(8) \
> > 
> >  + _(9) _(10) _(11) _(12) _(13) _(14) _(15) _(16) \
> > 
> >  + _(17) _(18) _(19) _(20) _(21) _(22) _(23) _(24) \
> > 
> >  + _(25) _(26) _(27) _(28) _(29) _(30) _(31)
> > 
> 
> Is 0 not valid?
> 

Yes, the MMD starts at 1. See "include/uapi/linux/mdio.h".

> > 
> > +#define MMD_DEVICE_ID_ATTR(n) \
> > 
> >  +static ssize_t mmd##n##_device_id_show(struct device *dev, \
> > 
> >  + struct device_attribute *attr, char *buf) \
> > 
> >  +{ \
> > 
> >  + struct phy_device *phydev = to_phy_device(dev); \
> > 
> >  + return sysfs_emit(buf, "0x%.8lx\n", \
> > 
> >  + (unsigned long)phydev->c45_ids.device_ids[n]); \
> > 
> >  +} \
> > 
> >  +static DEVICE_ATTR_RO(mmd##n##_device_id)
> > 
> 
> This macro magic i can follow, you see this quite a bit in the kernel.
> 

Okay.

> > 
> > +
> > 
> >  +#define _(x) MMD_DEVICE_ID_ATTR(x);
> > 
> >  +MMD_INDICES
> > 
> >  +#undef _
> > 
> >  +
> > 
> >  +static struct attribute *phy_mmd_attrs[] = {
> > 
> >  + #define _(x) &dev_attr_mmd##x##_device_id.attr,
> > 
> >  + MMD_INDICES
> > 
> >  + #undef _
> > 
> >  + NULL
> > 
> >  +};
> > 
> 
> If i squint at this enough, i can work it out, but generally a much
> 
> more readable KISS approach is taken, of just invoking a macro 32
> 
> times. See mdio_bus.c as an example.
> 

Okay.

>  Andrew
> 
> ---
> 
> pw-bot: cr
>