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

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

May 23, 2025 at 9:55 PM, "Andrew Lunn" <andrew@lunn.ch> wrote:



> 
> > 
> > +What: /sys/class/mdio_bus/<bus>/<device>/c45_phy_ids
> > 
> >  +Date: May 2025
> > 
> >  +KernelVersion: 6.16
> > 
> >  +Contact: netdev@vger.kernel.org
> > 
> >  +Description:
> > 
> >  + This attribute contains the 32-bit PHY Identifier as reported
> > 
> >  + by the device during bus enumeration, encoded in hexadecimal.
> > 
> >  + These C45 IDs are used to match the device with the appropriate
> > 
> >  + driver.
> > 
> 
> https://docs.kernel.org/filesystems/sysfs.html#attributes
> 
>  Attributes should be ASCII text files, preferably with only one
> 
>  value per file. It is noted that it may not be efficient to contain
> 
>  only one value per file, so it is socially acceptable to express an
> 
>  array of values of the same type.
> 
> These are static values, so efficiency is not an issue.
> 
> It might be better to have a directory
> 
> /sys/class/mdio_bus/<bus>/<device>/c45_phy_ids and then for each MMD
> 
> create a file. I would also suggest using is_visible() == 0 for those
> 
> with an ID == 0.
> 

is_visible only hide files, not directory. It will look like this:

c45 device:
$ ls /sys/class/net/eth0/phydev/
attached_dev  driver  of_node         phy_id         power       subsystem
c45_phy_ids   hwmon   phy_has_fixups  phy_interface  statistics  uevent

$ ls /sys/class/net/eth0/phydev/c45_phy_ids
mmd10_device_id  mmd17_device_id  mmd23_device_id  mmd2_device_id   mmd7_device_id
mmd11_device_id  mmd18_device_id  mmd24_device_id  mmd30_device_id  mmd8_device_id
mmd12_device_id  mmd19_device_id  mmd25_device_id  mmd31_device_id  mmd9_device_id
mmd13_device_id  mmd1_device_id   mmd26_device_id  mmd3_device_id
mmd14_device_id  mmd20_device_id  mmd27_device_id  mmd4_device_id
mmd15_device_id  mmd21_device_id  mmd28_device_id  mmd5_device_id
mmd16_device_id  mmd22_device_id  mmd29_device_id  mmd6_device_id


c22 device:
$ ls /sys/class/net/eth0/phydev/
attached_dev  driver  of_node         phy_id         power       subsystem
c45_phy_ids   hwmon   phy_has_fixups  phy_interface  statistics  uevent

$ ls /sys/class/net/eth0/phydev/c45_phy_ids


So is that fine? 

>  Andrew
>