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| author | Andreas Klinger <ak@it-klinger.de> | 2019-09-09 14:37:48 +0200 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2019-10-22 12:58:07 +0100 |
| commit | 68d8ab3cf1a98e9d296221afdb6433715fd57535 (patch) | |
| tree | 475034390dbcbf1afdef5b6ce0c2d9301def02d9 | |
| parent | 1cd92d42dbfff03bdd209fd6ccd5aec395faa915 (diff) | |
| download | linux-stable-68d8ab3cf1a98e9d296221afdb6433715fd57535.tar.gz linux-stable-68d8ab3cf1a98e9d296221afdb6433715fd57535.tar.bz2 linux-stable-68d8ab3cf1a98e9d296221afdb6433715fd57535.zip | |
iio: adc: hx711: optimize performance in read cycle
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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| -rw-r--r-- | drivers/iio/adc/hx711.c | 22 |
1 files changed, 5 insertions, 17 deletions
diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c index 62e6c8badd22..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; @@ -185,8 +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) { /* @@ -202,22 +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; |