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>
---
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;
--
2.11.0
