| Message ID | 20190909123746.lvd2q3dwgaksktuy@arbad (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: hx711: fix and optimize sampling of data | expand |
On Mon, 9 Sep 2019 14:37:48 +0200 Andreas Klinger <ak@it-klinger.de> 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@it-klinger.de> 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! 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;
On Sun, 15 Sep 2019 13:59:48 +0100 Jonathan Cameron <jic23@kernel.org> wrote: > On Mon, 9 Sep 2019 14:37:48 +0200 > Andreas Klinger <ak@it-klinger.de> 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@it-klinger.de> > 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; >
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;
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@it-klinger.de> --- drivers/iio/adc/hx711.c | 23 +++++------------------ 1 file changed, 5 insertions(+), 18 deletions(-)