On Wed, Mar 12, 2014 at 09:21:00AM +0100, Christian Riesch wrote: > > Do you think it is possible to extend this in the future, e.g. for > selecting the polarity of periodic output signals or for time > stamping of external signals (rising edge/falling edge), or duty > cycles of the periodic signal other than 50%? How could this be > done? Using the reserved fields in struct ptp_pin_desc?
Yes, this can be done, but this relates to the ptp_xyz_request ioctls and not to the ptp_pin_desc. You asked for three things. Here is how one might implement them. 1. selecting the polarity of periodic output signals ptp_perout_request.flags (new flag) 2. time stamping of external signals (rising edge/falling edge) This is already supported in the ptp_extts_request.flags field. The drivers just need to implement it. 3. duty cycles of the periodic signal other than 50%? Maybe using one of the ptp_perout_request.rsv fields. > Do you think the concept allows an extension for single pulse > output, e.g. programming a pin to output a single pulse at a given > time, as supported by the DP83640? Yes, either a new ioctl or maybe ptp_perout_request.flags with a ONE-SHOT flag. > If several DP83640 are connected together with the calibration > function, only the GPIOs of the master device can be used, right? I > guess this could also be extended in the future to use the GPIOs of > all DP83640, right? Or do you see a problem with your concept here? If the driver would combine all of the pins and functions over all the devices, that would be best. I think it would be tricky to implement, since the driver probe() function doesn't know how many more phyters to expect. Thanks, Richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
