diff mbox series

iio: adc: Add scaling support to exynos adc driver

Message ID BN6PR04MB066058A68D6471E7F6AFCFF7A3A20@BN6PR04MB0660.namprd04.prod.outlook.com (mailing list archive)
State Mainlined
Commit 754718a5b43c851546c3bb70e8d41bf81cb42b30
Headers show
Series iio: adc: Add scaling support to exynos adc driver | expand

Commit Message

Jonathan Bakker May 8, 2020, 9:14 p.m. UTC
Currently the driver only exposes the raw counts.  As we
have the regulator voltage and the maximum value (stored in
the data mask), we can trivially produce a scaling fraction
of voltage / max value.

This assumes that the regulator voltage is in fact the max
voltage, which appears to be the case for all mainline dts
and cross referenced with the public Exynos4412 and S5PV210
datasheets.

Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
---
 drivers/iio/adc/exynos_adc.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Jonathan Cameron May 10, 2020, 10:24 a.m. UTC | #1
On Fri,  8 May 2020 14:14:00 -0700
Jonathan Bakker <xc-racer2@live.ca> wrote:

> Currently the driver only exposes the raw counts.  As we
> have the regulator voltage and the maximum value (stored in
> the data mask), we can trivially produce a scaling fraction
> of voltage / max value.
> 
> This assumes that the regulator voltage is in fact the max
> voltage, which appears to be the case for all mainline dts
> and cross referenced with the public Exynos4412 and S5PV210
> datasheets.
> 
> Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>

Seems reasonable to me. I'd like an exynos Ack though before applying.

thanks,

Jonathan


> ---
>  drivers/iio/adc/exynos_adc.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index 22131a677445..9d29b56805cd 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -531,8 +531,19 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
>  	unsigned long timeout;
>  	int ret;
>  
> -	if (mask != IIO_CHAN_INFO_RAW)
> +	if (mask == IIO_CHAN_INFO_SCALE) {
> +		ret = regulator_get_voltage(info->vdd);
> +		if (ret < 0)
> +			return ret;
> +
> +		/* Regulator voltage is in uV, but need mV */
> +		*val = ret / 1000;
> +		*val2 = info->data->mask;
> +
> +		return IIO_VAL_FRACTIONAL;
> +	} else if (mask != IIO_CHAN_INFO_RAW) {
>  		return -EINVAL;
> +	}
>  
>  	mutex_lock(&indio_dev->mlock);
>  	reinit_completion(&info->completion);
> @@ -683,6 +694,7 @@ static const struct iio_info exynos_adc_iio_info = {
>  	.channel = _index,				\
>  	.address = _index,				\
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
> +	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),	\
>  	.datasheet_name = _id,				\
>  }
>
Krzysztof Kozlowski May 11, 2020, 7:42 a.m. UTC | #2
On Sun, May 10, 2020 at 11:24:17AM +0100, Jonathan Cameron wrote:
> On Fri,  8 May 2020 14:14:00 -0700
> Jonathan Bakker <xc-racer2@live.ca> wrote:
> 
> > Currently the driver only exposes the raw counts.  As we
> > have the regulator voltage and the maximum value (stored in
> > the data mask), we can trivially produce a scaling fraction
> > of voltage / max value.
> > 
> > This assumes that the regulator voltage is in fact the max
> > voltage, which appears to be the case for all mainline dts
> > and cross referenced with the public Exynos4412 and S5PV210
> > datasheets.
> > 
> > Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
> 
> Seems reasonable to me. I'd like an exynos Ack though before applying.


It's correct, at least with ARMv7 Exynos datasheets

The few ARMv8 Exynos chips are silent about the voltage levels. The
Exynos 7 DTS board in mainline kernel does not have regulator but it
looks clearly like mistake.

I think they behave the same, so for Exynos:
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof

> thanks,
> 
> Jonathan
> 
>
Jonathan Cameron May 16, 2020, 6:19 p.m. UTC | #3
On Mon, 11 May 2020 09:42:32 +0200
Krzysztof Kozlowski <krzk@kernel.org> wrote:

> On Sun, May 10, 2020 at 11:24:17AM +0100, Jonathan Cameron wrote:
> > On Fri,  8 May 2020 14:14:00 -0700
> > Jonathan Bakker <xc-racer2@live.ca> wrote:
> >   
> > > Currently the driver only exposes the raw counts.  As we
> > > have the regulator voltage and the maximum value (stored in
> > > the data mask), we can trivially produce a scaling fraction
> > > of voltage / max value.
> > > 
> > > This assumes that the regulator voltage is in fact the max
> > > voltage, which appears to be the case for all mainline dts
> > > and cross referenced with the public Exynos4412 and S5PV210
> > > datasheets.
> > > 
> > > Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>  
> > 
> > Seems reasonable to me. I'd like an exynos Ack though before applying.  
> 
> 
> It's correct, at least with ARMv7 Exynos datasheets
> 
> The few ARMv8 Exynos chips are silent about the voltage levels. The
> Exynos 7 DTS board in mainline kernel does not have regulator but it
> looks clearly like mistake.
> 
> I think they behave the same, so for Exynos:
> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to poke at it.

Thanks,

Jonathan

> 
> Best regards,
> Krzysztof
> 
> > thanks,
> > 
> > Jonathan
> > 
> >
diff mbox series

Patch

diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
index 22131a677445..9d29b56805cd 100644
--- a/drivers/iio/adc/exynos_adc.c
+++ b/drivers/iio/adc/exynos_adc.c
@@ -531,8 +531,19 @@  static int exynos_read_raw(struct iio_dev *indio_dev,
 	unsigned long timeout;
 	int ret;
 
-	if (mask != IIO_CHAN_INFO_RAW)
+	if (mask == IIO_CHAN_INFO_SCALE) {
+		ret = regulator_get_voltage(info->vdd);
+		if (ret < 0)
+			return ret;
+
+		/* Regulator voltage is in uV, but need mV */
+		*val = ret / 1000;
+		*val2 = info->data->mask;
+
+		return IIO_VAL_FRACTIONAL;
+	} else if (mask != IIO_CHAN_INFO_RAW) {
 		return -EINVAL;
+	}
 
 	mutex_lock(&indio_dev->mlock);
 	reinit_completion(&info->completion);
@@ -683,6 +694,7 @@  static const struct iio_info exynos_adc_iio_info = {
 	.channel = _index,				\
 	.address = _index,				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),	\
 	.datasheet_name = _id,				\
 }