[PATCH 3/3] iio: adc: ti-ads8344: optimize consumption

From: Alexandre Belloni
Date: Wed Apr 15 2020 - 17:23:37 EST


Set the clock mode only once, at probe time and then keep the ADC powered
down between conversions.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
drivers/iio/adc/ti-ads8344.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c
index 9b2d3a8ea6bd..0804650d8d8a 100644
--- a/drivers/iio/adc/ti-ads8344.c
+++ b/drivers/iio/adc/ti-ads8344.c
@@ -65,7 +65,7 @@ static const struct iio_chan_spec ads8344_channels[] = {
};

static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
- bool differential)
+ bool differential, u8 clock)
{
struct spi_device *spi = adc->spi;
int ret;
@@ -75,7 +75,7 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
if (!differential)
buf[0] |= ADS8344_SINGLE_END;
buf[0] |= ADS8344_CHANNEL(channel);
- buf[0] |= ADS8344_CLOCK_INTERNAL;
+ buf[0] |= clock;

ret = spi_write(spi, buf, 1);
if (ret)
@@ -100,7 +100,7 @@ static int ads8344_read_raw(struct iio_dev *iio,
case IIO_CHAN_INFO_RAW:
mutex_lock(&adc->lock);
*value = ads8344_adc_conversion(adc, channel->scan_index,
- channel->differential);
+ channel->differential, 0);
mutex_unlock(&adc->lock);
if (*value < 0)
return *value;
@@ -155,6 +155,11 @@ static int ads8344_probe(struct spi_device *spi)
if (ret)
return ret;

+ /* Do a dummy read and set external clock mode */
+ ret = ads8344_adc_conversion(adc, 0, 0, ADS8344_CLOCK_INTERNAL);
+ if (ret < 0)
+ return ret;
+
spi_set_drvdata(spi, indio_dev);

ret = iio_device_register(indio_dev);
--
2.25.2