Messages in this thread | | | Date | Fri, 21 Oct 2022 14:02:08 +0300 | From | Matti Vaittinen <> | Subject | Re: [PATCH v3 2/3] iio: accel: Support Kionix/ROHM KX022A accelerometer |
| |
On 10/21/22 13:49, Andy Shevchenko wrote: > On Fri, Oct 21, 2022 at 10:10:08AM +0300, Matti Vaittinen wrote: >> On 10/20/22 17:34, Andy Shevchenko wrote: >>> On Thu, Oct 20, 2022 at 02:37:15PM +0300, Matti Vaittinen wrote: > > ... > >>>> + ret = regmap_bulk_read(data->regmap, chan->address, &data->buffer, >>>> + sizeof(__le16)); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + *val = le16_to_cpu(data->buffer[0]); >>> >>> 'p'-variant of the above would look better >>> >>> *val = le16_to_cpup(data->buffer); >>> >>> since it will be the same as above address without any additional arithmetics. >>> >> >> I guess there is no significant performance difference? To my eye the >> le16_to_cpu(data->buffer[0]) is much more clear. I see right from the call >> that we have an array here and use the first member. If there is no obvious >> technical merit for using le16_to_cpup(data->buffer) over >> le16_to_cpu(data->buffer[0]), then I do really prefer the latter for >> clarity. > > Then you probably wanted to have &data->buffer[0] as a parameter to > regmap_bulk_read()?
Yes! Thanks.
> > ... > >>>> + if (data->trigger_enabled) { >>>> + iio_trigger_poll_chained(data->trig); >>>> + ret = IRQ_HANDLED; >>>> + } >>>> + >>>> + if (data->state & KX022A_STATE_FIFO) { >>> >>>> + ret = __kx022a_fifo_flush(idev, KX022A_FIFO_LENGTH, true); >>>> + if (ret > 0) >>>> + ret = IRQ_HANDLED; >>> >>> I don't like it. Perhaps >>> >>> bool handled = false; >>> int ret; >>> >>> ... >>> ret = ... >>> if (ret > 0) >>> handled = true; >>> ... >>> >>> return IRQ_RETVAL(handled); >> >> I don't see the benefit of adding another variable 'handled'. >> If I understand correctly, it just introduces one extra 'if' in IRQ thread >> handling while hiding the return value in IRQ_RETVAL() - macro. >> >> I do like seeing the IRQ_NONE being returned by default and IRQ_HANDLED only >> when "handlers" are successfully executed. Adding extra variable just >> obfuscates this (from my eyes) while adding also the additional 'if'. > > You assigning semantically different values to the same variable inside the > function.
Ah, yes! This was really a bug making it way in. I guess you may just have saved me from some not-that-funny debugging session... Well spotted!
I still don't like hiding the IRQ_HANDLED / IRQ_NONE. I'll just go for
if (data->state & KX022A_STATE_FIFO) {
int ok;
ok = __kx022a_fifo_flush(idev, KX022A_FIFO_LENGTH, true); if (ok > 0)
ret = IRQ_HANDLED;
}
for v4. (Which I try to send still today before my memory is flushed by the weekend :])
Thanks a lot!
Yours -- Matti
-- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
| |