Hi Jonathan, see answer to your question below.
Andreas Jonathan Cameron <[email protected]> schrieb am Sat, 02. Dec 13:22: > On Thu, 30 Nov 2017 22:44:45 +0100 > Andreas Klinger <[email protected]> wrote: > > > return value in hx711_reset() should indicate status of dout > > otherwise the calling function is reporting an error als false positive > > > > wait up to 1 second until the device is in normal state > > by changing the channel on every trigger event it turned out that the > > former 100 ms are not enough for waiting until the device is in normal mode > > What is the ultimate result of this? I'm trying to assess if we want > to marked it for stable trees or just apply it ready for the next > merge window. It think it means that two reads too close to each > other will always result in an error for the second one rather than > the intended delay and then succeed? Exactly. If one is accessing to fast the second access will fail. Especially when using a trigger the second channel is never read without error. > > Thanks, > > Jonathan > > > > Signed-off-by: Andreas Klinger <[email protected]> > > --- > > drivers/iio/adc/hx711.c | 13 ++++++------- > > 1 file changed, 6 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c > > index d773fd69a76d..eabd2e66aca3 100644 > > --- a/drivers/iio/adc/hx711.c > > +++ b/drivers/iio/adc/hx711.c > > @@ -153,15 +153,16 @@ static int hx711_wait_for_ready(struct hx711_data > > *hx711_data) > > int i, val; > > > > /* > > - * a maximum reset cycle time of 56 ms was measured. > > - * we round it up to 100 ms > > + * in some rare cases the reset takes quite a long time > > + * especially when the channel is changed. > > + * Allow up to one second for it > > */ > > for (i = 0; i < 100; i++) { > > val = gpiod_get_value(hx711_data->gpiod_dout); > > if (!val) > > break; > > - /* sleep at least 1 ms */ > > - msleep(1); > > + /* sleep at least 10 ms */ > > + msleep(10); > > } > > if (val) > > return -EIO; > > @@ -203,9 +204,7 @@ static int hx711_reset(struct hx711_data *hx711_data) > > * after a dummy read we need to wait vor readiness > > * for not mixing gain pulses with the clock > > */ > > - ret = hx711_wait_for_ready(hx711_data); > > - if (ret) > > - return ret; > > + val = hx711_wait_for_ready(hx711_data); > > } > > > > return val; > --
