Messages in this thread | | | Date | Mon, 5 Dec 2022 17:03:28 +0100 | From | Uwe Kleine-König <> | Subject | Re: [PATCH v12 1/2] pwm: add microchip soft ip corePWM driver |
| |
Hello Conor,
On Mon, Dec 05, 2022 at 03:21:55PM +0000, Conor Dooley wrote: > I came into work today thinking that I could just rebase on top of your > patchset and send out a v13, but that was unfortunately not the case :/ > > So uh, it turns out that I was wrong about the behaviour of the > sync_update register's bit. > It turns out that that bit holds it's value until the IP block is reset, > and /does not/ get cleared at the start of the next period. > I'm really not sure how it worked when I tested the other week [0], so I > spent the first half of the day trying to figure out what on earth had > happened to my FPGA image. I must've picked the wrong image when I went > to test it the other week that had the wrong configuration somehow. > > As a result, I've gone and hacked up another way of transferring the > burden of waiting - setting a timer for the period, backed by a > completion. get_state() and apply() now both check for the completion > and time out otherwise. I'm half tempted to tack RFC back onto the > series as I have not really messed with timers at all before and may > have done something off the wall. > > I pushed it out (see [1] in case you'd like to look) so that the bots > can have a play with it, since it'll be a few weeks before I'll have a > chance to properly test that I've broken nothing with this.
I didn't look, but I'm convinced you don't need a timer. Something like the following should work, shouldn't it?:
- in .apply() check the current time, add the current period and store the result to ddata->updatetimestamp - in .get_state do: if (current_time >= ddata->updatetimestamp) process fine else: timeout (or wait until ddata->updatetimestamp?)
Actually I'd prefer to wait instead of -ETIMEOUT. Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ | [unhandled content-type:application/pgp-signature] | |