Re: [PATCH 2/3] ptp: Add clock name to uevent

[Sven Schnelle]

Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes:

> On Tue, Oct 15, 2024 at 02:02:17PM +0200, Sven Schnelle wrote:
>> Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes:
>> 
>> > On Tue, Oct 15, 2024 at 12:54:13PM +0200, Sven Schnelle wrote:
>> >> To allow users to have stable device names with the help of udev,
>> >> add the name to the udev event that is sent when a new PtP clock
>> >> is available. The key is called 'PTP_CLOCK_NAME'.
>> >
>> > Where are you documenting this new user/kernel api you are adding?
>> >
>> >> 
>> >> Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
>> >> ---
>> >>  drivers/ptp/ptp_clock.c | 11 ++++++++++-
>> >>  1 file changed, 10 insertions(+), 1 deletion(-)
>> >> 
>> >> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
>> >> index c56cd0f63909..15937acb79c6 100644
>> >> --- a/drivers/ptp/ptp_clock.c
>> >> +++ b/drivers/ptp/ptp_clock.c
>> >> @@ -25,9 +25,11 @@
>> >>  #define PTP_PPS_EVENT PPS_CAPTUREASSERT
>> >>  #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
>> >>  
>> >> +static int ptp_udev_uevent(const struct device *dev, struct kobj_uevent_env *env);
>> >>  const struct class ptp_class = {
>> >>  	.name = "ptp",
>> >> -	.dev_groups = ptp_groups
>> >> +	.dev_groups = ptp_groups,
>> >> +	.dev_uevent = ptp_udev_uevent
>> >>  };
>> >>  
>> >>  /* private globals */
>> >> @@ -514,6 +516,13 @@ EXPORT_SYMBOL(ptp_cancel_worker_sync);
>> >>  
>> >>  /* module operations */
>> >>  
>> >> +static int ptp_udev_uevent(const struct device *dev, struct kobj_uevent_env *env)
>> >> +{
>> >> +	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
>> >> +
>> >> +	return add_uevent_var(env, "PTP_CLOCK_NAME=%s", ptp->info->name);
>> >
>> > Why is this needed?  Can't you get the name from the sysfs paths, the
>> > symlink should be there already.
>> 
>> You mean the 'clock_name' attribute in sysfs?
>
> Great, yes, it's right there.
>
>> That would require to
>> write some script to iterate over all ptp devices and check the name,
>> or is there a way to match that in udev?
>
> Yes there is.  Please use that :)

Indeed. Sorry, will drop the patch.