On 2020-09-24 08:41, Sanchayan Maity wrote: > On 20-09-22 02:51:11, Andy Duan wrote: >> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> >> > On Mon, 21 Sep 2020 14:27:28 +0200 >> > Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: >> > >> > > On 2020-09-21 10:57:03 [+0100], Jonathan Cameron wrote: >> > > > So looking at this the other way, are there any significant risks >> > > > associated with this change? If not I'm tempted to queue them up >> > > > and we have the rcX time to fix anything we've missed (just like >> > > > every other patch!) >> > > >> > > I've been told that it only performs IRQ-thread wake-ups in hard-IRQ >> > > context. This is fine then. >> > > >> > drivers/iio/adc/vf610-adc.c >> > >> > However, there looks to be a lot more wrong in there than just this. >> > So normally for a device with a data ready signal like this we would hook up as >> > follows. >> > >> > Data ready #1 -> IRQ chip (trigger) -> Read sensor #1 + >> > iio_trigger_notify_done() >> > -> Read sensor #2 + >> > iio_trigger_notify_done() >> > >> > (note that the read etc is normally in a thread - all we do in interrupt context is >> > usually to grab a timestamp if that makes sense for a given sensor). >> > >> > This driver does both of. >> > Data ready -> Read data from itself and call iio_trigger_notify_done() IRQ chip >> > for a different trigger -> Take a timestamp and never call >> > iio_trigger_notify_done() >> > or read any data for that matter. >> > >> > Which won't do what we want at all. >> > >> > Andy, if I have a go at fixing this are you able to test the result? >> > I think the simplest is probably to introduce a trigger to tie the two halves >> > together. >> > We can set it as the default trigger so things should keep on working for existing >> > users. >> > >> > For more general case, we should probably have two functions. >> > >> > iio_trigger_notify_done() which is only called from places we can sleep. >> > iio_trigger_notify_done_no_action() which only decrements the counter (or >> > given this is only called inside industrialio-trigger.c could just replace with >> > atomic_dec(&trig->use_count)). >> > >> >> Sanchayan, can you help to verify the fixes that Jonathan will send out ? >> > > Sorry for the delay in reply. Unfortunately can't as I do not access to the > hardware having left Toradex. > > CCed Stefan Agner who might be able to help. > > @Stefan > > Hello Stefan :), may be you can help here? Hi all, I do have access to the hardware and can run a test if required. I guess I would just need to test if ADC sampling still work with something like tools/iio/iio_generic_buffer.c? -- Stefan
