Messages in this thread | | | From | Peter Korsgaard <> | Subject | Re: [PATCH 3/3] i2c:ocores: add polling interface | Date | Mon, 29 Oct 2018 14:04:13 +0100 |
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>>>>> "Federico" == Federico Vaga <federico.vaga@cern.ch> writes:
Hi,
>> >> Where does this 10 come from? >> > >> > It's true, it's just a random number. It can be zero as well, and we ask >> > the system to just sleep for that amount of time. >> > >> > (1) usleep_range(sleep_min, sleep_min); >> >> Or just usleep(sleep_min);
> This does not exist as far as I know; the alternative is an active wait with > udelay. But then, it is not that different from just start polling TIP or BUSY > flags.
Ahh yes.
> I think that something like this could be better
> (2) usleep_range(sleep_min, sleep_min * XXX);
> But. > Since it is better to make this patch ready for xfer_irqless, then I will > definitively go for udelay(). The reason is that, xfer_irqless may run in > atomic context where we can't sleep at all.
Great! BTW I noticed that your sleep_min calculation looked odd:
int sleep_min = (8/i2c->bus_clock_khz) * 1000; /* us for 8bits
bus_clock_khz almost certainly will be bigger than 8 (E.G. likely 100KHz), so the above set sleep_min to 0. Please move the * 1000 before the division.
-- Bye, Peter Korsgaard
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