Re: [PATCH net-next v2 1/2] net: phy: c45 scanning: Don't consider -ENODEV fatal

[Andrew Lunn <andrew@lunn.ch>]

On Tue, Apr 07, 2026 at 11:15:49AM -0700, Charles Perry wrote:
> On Sun, Feb 04, 2024 at 05:14:14PM -0600, Andrew Lunn wrote:
> > When scanning the MDIO bus for C22 devices, the driver returning
> > -ENODEV is not considered fatal, it just indicates the MDIO bus master
> > knows there is no device at that address, maybe because of hardware
> > limitation.
> > 
> > Make the C45 scan code act on -ENODEV the same way, to make C22 and
> > C45 more uniform.
> > 
> > It is expected all reads for a given address will return -ENODEV, so
> > within get_phy_c45_ids() only the first place a read occurs has been
> > changed.
> > 
> > Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> > ---
> >  drivers/net/phy/phy_device.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> > index 52828d1c64f7..962ab53c23ff 100644
> > --- a/drivers/net/phy/phy_device.c
> > +++ b/drivers/net/phy/phy_device.c
> > @@ -780,7 +780,7 @@ static int get_phy_c45_devs_in_pkg(struct mii_bus *bus, int addr, int dev_addr,
> >   * and identifiers in @c45_ids.
> >   *
> >   * Returns zero on success, %-EIO on bus access error, or %-ENODEV if
> > - * the "devices in package" is invalid.
> > + * the "devices in package" is invalid or no device responds.
> >   */
> >  static int get_phy_c45_ids(struct mii_bus *bus, int addr,
> >  			   struct phy_c45_device_ids *c45_ids)
> > @@ -803,7 +803,11 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr,
> >  			 */
> >  			ret = phy_c45_probe_present(bus, addr, i);
> >  			if (ret < 0)
> > -				return -EIO;
> > +				/* returning -ENODEV doesn't stop bus
> > +				 * scanning
> > +				 */
> > +				return (phy_reg == -EIO ||
> > +					phy_reg == -ENODEV) ? -ENODEV : -EIO;
> 
> Hello Andrew,
> 
> Did you meant "ret" instead of "phy_reg" here?
> 
> "phy_reg" doesn't make sense here because you would have already returned
> in the previous iteration of the loop.

Hum, good catch. That makes no sense. Looks like i cut/pasted from the
C22 code, and did not fixup the variable name.

	Andrew