[PATCH net] net: stmmac: report phc_index as -1 when no PTP clock is registered

[Rahul Rameshbabu]

On Sat, 12 Sep, 2026 23:39:02 +0200 Maxime Chevallier <maxime.chevallier at bootlin.com> wrote:
> Hi Lorenzo,
>
> On 9/12/26 23:16, Lorenzo Bianconi wrote:
>> When hardware timestamping is supported but no PTP clock has been
>> registered yet (e.g. while the interface is down), stmmac_get_ts_info()
>> currently reports phc_index as 0. Zero is a valid PHC index and would
>> make userspace resolve the wrong clock; the absence of a clock should
>> be reported as -1, matching ethtool_init_tsinfo() and
>> ethtool_op_get_ts_info().
>> 
>> Report -1 when no PTP clock is available.
>> 
>> Fixes: 9364fa7fcf12 ("net: stmmac: Remove setting of RX software timestamp")
>> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at oss.qualcomm.com>
>
> Ah nice, I've briefly saw that just yesterday but haven't started digging,
> thanks for fixing this :)
>
> Reviewed-by: Maxime Chevallier <maxime.chevallier at bootlin.com>

Thanks for the change. Good catch.

Reviewed-by: Rahul Rameshbabu <rrameshbabu at nvidia.com>

>
> Maxime