Messages in this thread | | | From | "Keller, Jacob E" <> | Subject | RE: [PATCH v4 2/2] PTP: add support for one-shot output | Date | Tue, 24 Sep 2019 21:53:37 +0000 |
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> -----Original Message----- > From: Hall, Christopher S > Sent: Tuesday, September 24, 2019 1:24 PM > To: Keller, Jacob E <jacob.e.keller@intel.com>; Felipe Balbi > <felipe.balbi@linux.intel.com>; Richard Cochran <richardcochran@gmail.com> > Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: RE: [PATCH v4 2/2] PTP: add support for one-shot output > > > -----Original Message----- > > From: Keller, Jacob E > > Sent: Tuesday, September 24, 2019 12:23 PM > > To: Felipe Balbi <felipe.balbi@linux.intel.com>; Richard Cochran > > <richardcochran@gmail.com> > > Cc: Hall, Christopher S <christopher.s.hall@intel.com>; > > netdev@vger.kernel.org; linux-kernel@vger.kernel.org > > Subject: RE: [PATCH v4 2/2] PTP: add support for one-shot output > > > > > > > > > -----Original Message----- > > > From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] > > On > > > Behalf Of Felipe Balbi > > > Sent: Tuesday, September 10, 2019 11:16 PM > > > To: Richard Cochran <richardcochran@gmail.com> > > > Cc: Hall, Christopher S <christopher.s.hall@intel.com>; > > netdev@vger.kernel.org; > > > linux-kernel@vger.kernel.org; Felipe Balbi > > <felipe.balbi@linux.intel.com> > > > Subject: [PATCH v4 2/2] PTP: add support for one-shot output > > > > > > Some controllers allow for a one-shot output pulse, in contrast to > > > periodic output. Now that we have extensible versions of our IOCTLs, we > > > can finally make use of the 'flags' field to pass a bit telling driver > > > that if we want one-shot pulse output. > > > > > > Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> > > > --- > > > > > > Changes since v3: > > > - Remove bogus bitwise negation > > > > > > Changes since v2: > > > - Add _PEROUT_ to bit macro > > > > > > Changes since v1: > > > - remove comment from .flags field > > > > > > include/uapi/linux/ptp_clock.h | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/include/uapi/linux/ptp_clock.h > > b/include/uapi/linux/ptp_clock.h > > > index 9a0af3511b68..f16301015949 100644 > > > --- a/include/uapi/linux/ptp_clock.h > > > +++ b/include/uapi/linux/ptp_clock.h > > > @@ -38,8 +38,8 @@ > > > /* > > > * Bits of the ptp_perout_request.flags field: > > > */ > > > -#define PTP_PEROUT_VALID_FLAGS (0) > > > - > > > +#define PTP_PEROUT_ONE_SHOT (1<<0) > > > +#define PTP_PEROUT_VALID_FLAGS (PTP_PEROUT_ONE_SHOT) > > > /* > > > * struct ptp_clock_time - represents a time value > > > * > > > @@ -77,7 +77,7 @@ struct ptp_perout_request { > > > struct ptp_clock_time start; /* Absolute start time. */ > > > struct ptp_clock_time period; /* Desired period, zero means disable. > > */ > > > unsigned int index; /* Which channel to configure. */ > > > - unsigned int flags; /* Reserved for future use. */ > > > + unsigned int flags; > > > unsigned int rsv[4]; /* Reserved for future use. */ > > > }; > > > > > > -- > > > 2.23.0 > > > > Hi Felipe, > > > > Do you have any examples for how you envision using this? I don't see any > > drivers or other code on the list for doing so. > > > > Additionally, it seems weird because we do not have support for specifying > > the pulse width. I guess you leave that up to driver choice? > > > > Thanks, > > Jake >
Also a quick note/question:
Is there a spot where flags are explicitly checked and rejected? I don't see any driver which would reject this as "not an acceptable configuration".
I.e. if a function calls the PEROUT_REQUEST2 ioctl, they will pass the flag through, and drivers today don't seem to bother checking flags at all.
I think we also need a patch so that all drivers are updated to reject non-zero flags, ensuring that they do not attempt to configure a request incorrectly.
Thanks, Jake
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