Messages in this thread | | | Date | Fri, 17 Mar 2023 17:34:28 +0100 | Subject | Re: [PATCH v4] pps: Add elapsed realtime timestamping | From | Rodolfo Giometti <> |
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On 17/03/23 15:22, Greg KH wrote: > On Fri, Mar 17, 2023 at 03:04:31PM +0100, Rodolfo Giometti wrote: >> On 17/03/23 10:51, Alex Komrakov wrote: >>>> + if (!(pps->info.mode & PPS_CAPTURECLEAR)) >>>> + return 0; Why are you not returning an error? >>> [AK] I used the style in this file sysfs.c. >>> assert_show() and clear_show() have the same condition. >>> When '& PPS_CAPTURECLEAR' -- 0 means no interrupt asserted and it is not error >>> Probably Rodolfo can get more info why return 0 >> >> It's just as Alex said, if the PPS source has no PPS_CAPTUREASSERT or >> PPS_CAPTURECLEAR mode it should not print ASSERT and CLEAR info. > > But shouldn't you return an error instead of an empty string?
This is not an error... it's just a disabled capability. :)
>>> And why are these sysfs files even present if the mode is not set >>> properly? Can the mode be set while the device is attached or is this >>> only defined at probe time? If at probe time, just never create these >>> files. >>> [AK] we can understand mode is set when interrupts asserted and >>> file assert_elapsed will be updated. >> >> PPS source's "mode bits" can be set at runtime via PPS_SETPARAMS. > > Ok, that's good to know. But I think the error return value is a better > indication that something went wrong here and this attribute does not > work for this device at this point in time.
I see... however I suppose several code relays on this behavior.
If we decide to change it, which should be the better way to do it? Any suggestions are appreciated.
Ciao,
Rodolfo
-- GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@linux.it Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
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