diff mbox series

[v2,2/2] iio: adc: ti-ads8344: optimize consumption

Message ID 20200416205428.437503-3-alexandre.belloni@bootlin.com
State New, archived
Headers show
Series iio: adc: ti-ads8344: driver improvements | expand

Commit Message

Alexandre Belloni April 16, 2020, 8:54 p.m. UTC
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@bootlin.com>
---
 drivers/iio/adc/ti-ads8344.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Jonathan Cameron April 18, 2020, 3:13 p.m. UTC | #1
On Thu, 16 Apr 2020 22:54:28 +0200
Alexandre Belloni <alexandre.belloni@bootlin.com> wrote:

> 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@bootlin.com>
Looks fine to me. I'd like to be lazy and not take this until the fix is
in my upstream (even though I suspect the merge would be fine).

Give me a poke if I seem to have forgotten this after that is true!

Thanks,

Jonathan

> ---
>  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 abe4b56c847c..40e7a9eee189 100644
> --- a/drivers/iio/adc/ti-ads8344.c
> +++ b/drivers/iio/adc/ti-ads8344.c
> @@ -72,7 +72,7 @@ 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;
> @@ -81,7 +81,7 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
>  	if (!differential)
>  		adc->tx_buf |= ADS8344_SINGLE_END;
>  	adc->tx_buf |= ADS8344_CHANNEL(channel);
> -	adc->tx_buf |= ADS8344_CLOCK_INTERNAL;
> +	adc->tx_buf |= clock;
>  
>  	ret = spi_write(spi, &adc->tx_buf, 1);
>  	if (ret)
> @@ -106,7 +106,7 @@ 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;
> @@ -161,6 +161,11 @@ 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);
Alexandre Belloni April 30, 2020, 8:17 p.m. UTC | #2
Hi,

On 18/04/2020 16:13:22+0100, Jonathan Cameron wrote:
> On Thu, 16 Apr 2020 22:54:28 +0200
> Alexandre Belloni <alexandre.belloni@bootlin.com> wrote:
> 
> > 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@bootlin.com>
> Looks fine to me. I'd like to be lazy and not take this until the fix is
> in my upstream (even though I suspect the merge would be fine).
> 
> Give me a poke if I seem to have forgotten this after that is true!
> 

It now landed in your upstream but I guess you want to take Gregory's
patch as a fix first. To be honest I don't think any of the fixes are
urgent as it seems we are the only users of the particular ADC.
diff mbox series

Patch

diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c
index abe4b56c847c..40e7a9eee189 100644
--- a/drivers/iio/adc/ti-ads8344.c
+++ b/drivers/iio/adc/ti-ads8344.c
@@ -72,7 +72,7 @@  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;
@@ -81,7 +81,7 @@  static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
 	if (!differential)
 		adc->tx_buf |= ADS8344_SINGLE_END;
 	adc->tx_buf |= ADS8344_CHANNEL(channel);
-	adc->tx_buf |= ADS8344_CLOCK_INTERNAL;
+	adc->tx_buf |= clock;
 
 	ret = spi_write(spi, &adc->tx_buf, 1);
 	if (ret)
@@ -106,7 +106,7 @@  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;
@@ -161,6 +161,11 @@  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);