On Sun, 15 Sep 2019 13:59:48 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On Mon, 9 Sep 2019 14:37:48 +0200
> Andreas Klinger <ak@xxxxxxxxxxxxx> wrote:
>
> > Set gain in hx711_reset() to its default value after a reset cycle. This
> > omits one precautionary read cycle, because the read is performed in
> > hx711_set_gain_for_channel() anyway if gain has changed.
> >
> > Check for DOUT low and if its high wait some time if it goes down
> > instead of doing a blind reset cycle when DOUT is not down.
> >
> > This is a performance optimization which allows to query the sensor with
> > a higher frequency.
> >
> > Signed-off-by: Andreas Klinger <ak@xxxxxxxxxxxxx>
> Hi Andreas,
>
> This one seems to have a slightly non trivial interaction with patch 1
> so will have to wait until the fixes-togreg branch works it's way back
> around to the upstream for the togreg branch. Give me a poke if I seem
> to have lost it!
Applied.
Thanks,
Jonathan
>
> Thanks,
>
> Jonathan
>
> > ---
> > drivers/iio/adc/hx711.c | 23 +++++------------------
> > 1 file changed, 5 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
> > index 0678964dbd21..c8686558429b 100644
> > --- a/drivers/iio/adc/hx711.c
> > +++ b/drivers/iio/adc/hx711.c
> > @@ -23,6 +23,7 @@
> >
> > /* gain to pulse and scale conversion */
> > #define HX711_GAIN_MAX 3
> > +#define HX711_RESET_GAIN 128
> >
> > struct hx711_gain_to_scale {
> > int gain;
> > @@ -100,7 +101,6 @@ struct hx711_data {
> >
> > static int hx711_cycle(struct hx711_data *hx711_data)
> > {
> > - int val;
> > unsigned long flags;
> >
> > /*
> > @@ -186,8 +186,7 @@ static int hx711_wait_for_ready(struct hx711_data *hx711_data)
> >
> > static int hx711_reset(struct hx711_data *hx711_data)
> > {
> > - int ret;
> > - int val = gpiod_get_value(hx711_data->gpiod_dout);
> > + int val = hx711_wait_for_ready(hx711_data);
> >
> > if (val) {
> > /*
> > @@ -203,22 +202,10 @@ static int hx711_reset(struct hx711_data *hx711_data)
> > msleep(10);
> > gpiod_set_value(hx711_data->gpiod_pd_sck, 0);
> >
> > - ret = hx711_wait_for_ready(hx711_data);
> > - if (ret)
> > - return ret;
> > - /*
> > - * after a reset the gain is 128 so we do a dummy read
> > - * to set the gain for the next read
> > - */
> > - ret = hx711_read(hx711_data);
> > - if (ret < 0)
> > - return ret;
> > -
> > - /*
> > - * after a dummy read we need to wait vor readiness
> > - * for not mixing gain pulses with the clock
> > - */
> > val = hx711_wait_for_ready(hx711_data);
> > +
> > + /* after a reset the gain is 128 */
> > + hx711_data->gain_set = HX711_RESET_GAIN;
> > }
> >
> > return val;
>
