On 02/19/2017 01:09 PM, Jonathan Cameron wrote:

On 15/02/17 16:55, Fabrice Gasnier wrote:

quoted

Add documentation for 'st,adc-res' dt optional property.

Signed-off-by: Fabrice Gasnier <redacted>

I'm happy with this, but would like to leave time for a device tree review.

Ultimately we may well want to make this a generic property and call it something
like adc-resolution but perhaps we need to wait until we have a few more devices
supporting setting it via device tree to figure out what the best interface is.
It would exactly be a problem to support this as a deprecated binding at that
point.

Hi Jonathan,

I agree with you on this... It may be better to have generic property
for this, especially if you see that it will come in the near future.
May I suggest this prop to be less restrictive, e.g. like 
resolution-bits as is may also be worth for other device types, e.g. DAC 
as an example ?

Give me a poke if we hear nothing from Rob or Mark for say another week.

No news yet, but it can wait a little longer.

Please advise,
Regards,
Fabrice

Thanks,

Jonathan

quoted

---
 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
index 5dfc88e..45f7ff2 100644
--- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt

@@ -57,6 +57,9 @@ Optional properties:
 - dmas: Phandle to dma channel for this ADC instance.
   See ../../dma/dma.txt for details.
 - dma-names: Must be "rx" when dmas property is being used.
+- st,adc-res: Resolution (bits) to use for conversions. Must match device
+  available resolutions (e.g. can be 6, 8, 10 or 12 on stm32f4). Default
+  is maximum resolution if unset.

 Example:
 	adc: adc at 40012000 {

@@ -84,6 +87,7 @@ Example:
 			st,adc-channels = <8>;
 			dmas = <&dma2 0 0 0x400 0x0>;
 			dma-names = "rx";
+			st,adc-res = <8>;
 		};
 		...
 		other adc child nodes follow...