Re: [RFC] iio: adc: at91: fix acking DRDY irq (again)

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 12/06/2019 11:31:42+0200, Ladislav Michl wrote:
> On Wed, Jun 12, 2019 at 10:15:33AM +0200, Alexandre Belloni wrote:
> > On 11/06/2019 13:56:03+0200, Ladislav Michl wrote:
> > > Driver also contains some code for TC triggers. How is that supposed to
> > > work? [**] The very same manual states in chapter 39.5.5:
> > >   "If one of the TIOA outputs is selected, the corresponding Timer Counter
> > >    channel must be programmed in Waveform Mode."
> > > There are two drivers touching TC: drivers/clocksource/timer-atmel-tcb.c
> > > and drivers/pwm/pwm-atmel-tcb.c, they seem to conflict each other and
> > 
> > They don't, they can work simultaneously, on different TCBs. I'm still
> > planning to rework pwm-atmel-tcb to switch it to the proper binding.
> 
> Is there any draft how should that "proper binding" look like?
> By "conflict" I mean DT can be written so both race for the same resource,
> while I would expect timer definition with PWM and ADC using its phandle.
> 

Last part of https://lore.kernel.org/lkml/20170530215139.9983-2-alexandre.belloni@free-electrons.com/

This is not yet upstream but I'm planning to resend sometime in July.


> > > none of them is anyhow related to ADC driver. Here it would seem
> > > appropriate to have TC MFD driver and allocate timers for ADC, PWM and
> > > clocksource from there.
> > 
> > No, MFD is way too late for clocksource, this would break some platforms.
> > 
> > However, there is definitively some timer framework that is missing to
> > allow handling of timers that are not used as clocksource/clockevent
> > devices. So indeed, there is a missing piece to make the TC trigger
> > work.
> 
> Can that be done similar way drivers/clocksource/timer-ti-dm.c is
> implemented or do you have something else in mind?
> 

Yes, something similar but this could probably be made more generic as
this would benefit many other platforms too (i.e broadcom, nxp,
amlogic).


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com