Re: [PATCH v3 3/4] iio: adc: add STMPE ADC devicetree bindings

[Philippe Schenker <dev@pschenker.ch>]

On Sun, 2018-11-25 at 10:04 +0000, Jonathan Cameron wrote:
> On Fri, 23 Nov 2018 15:24:10 +0100
> Philippe Schenker <dev@pschenker.ch> wrote:
> 
> > From: Stefan Agner <stefan@agner.ch>
> > 
> > This adds the devicetree bindings for the STMPE ADC.
> > 
> > Signed-off-by: Stefan Agner <stefan@agner.ch>
> > Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
> > Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
> Clearly this will need review from input and mfd.
> 
> I've suggested inline that you split the realignment out to a
> separate patch for reviewability reasons.

Thank you again Jonathan for your feedback, and of course also all the others!

I will split it much more so everything will be much more readable in v4. You
suggested again, to use the naming 'adc {'. I know that this is standard naming,
but unfortunately, this naming is given by drivers/mfd/stmpe.c (line 1311). 
What do you suggest to do? break the naming scheme in mfd, or just use
'stmpe_adc {' ?

> 
> > ---
> > 
> > Changes in v3:
> >  - Reformatted documentation for touchscreen to use tabs and have a better
> >    overview of the settings.
> >  - Added note which adc-settings will take precedence.
> >  - changed typo in sample-time setting from 144 clocks to 124 clocks, as
> > stated
> >    in the datasheet.
> > 
> > Changes in v2:
> >  - Moved the bindings for ADC to the overlying mfd.
> >  - Reformatted for better readability
> > 
> >  .../devicetree/bindings/iio/adc/stmpe-adc.txt | 21 +++++++
> >  .../bindings/input/touchscreen/stmpe.txt      | 60 ++++++++++++-------
> >  .../devicetree/bindings/mfd/stmpe.txt         | 28 ++++++---
> >  3 files changed, 80 insertions(+), 29 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
> > b/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
> > new file mode 100644
> > index 000000000000..480e66422625
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
> > @@ -0,0 +1,21 @@
> > +STMPE ADC driver
> > +----------------
> > +
> > +Required properties:
> > + - compatible: "st,stmpe-adc"
> > +
> > +Optional properties:
> > +Note that the ADC is shared with the STMPE touchscreen. ADC related
> > settings
> > +have to be done in the mfd.
> > +- st,norequest-mask: bitmask specifying which ADC channels should _not_ be
> > +  requestable due to different usage (e.g. touch)
> > +
> > +Node name must be stmpe_adc and should be child node of stmpe node to
> > +which it belongs.
> > +
> > +Example:
> > +
> > +	stmpe_adc {
> 
> Can we use adc { here to match standard naming?
> 
> > +		compatible = "st,stmpe-adc";
> > +		st,norequest-mask = <0x0F>; /* dont use ADC CH3-0 */
> > +	};
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
> > b/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
> > index 127baa31a77a..414586513a02 100644
> > --- a/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
> > @@ -5,36 +5,52 @@ Required properties:
> >   - compatible: "st,stmpe-ts"
> >  
> >  Optional properties:
> > -- st,sample-time: ADC converstion time in number of clock.  (0 -> 36
> > clocks, 1 ->
> > -  44 clocks, 2 -> 56 clocks, 3 -> 64 clocks, 4 -> 80 clocks, 5 -> 96
> > clocks, 6
> > -  -> 144 clocks), recommended is 4.  
> > -- st,mod-12b: ADC Bit mode (0 -> 10bit ADC, 1 -> 12bit ADC)
> > -- st,ref-sel: ADC reference source (0 -> internal reference, 1 -> external
> > -  reference)
> > -- st,adc-freq: ADC Clock speed (0 -> 1.625 MHz, 1 -> 3.25 MHz, 2 || 3 ->
> > 6.5 MHz)
> > -- st,ave-ctrl: Sample average control (0 -> 1 sample, 1 -> 2 samples, 2 ->
> > 4
> > -  samples, 3 -> 8 samples)
> > -- st,touch-det-delay: Touch detect interrupt delay (0 -> 10 us, 1 -> 50 us,
> > 2 ->
> > -  100 us, 3 -> 500 us, 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
> > recommended
> > -  is 3
> > -- st,settling: Panel driver settling time (0 -> 10 us, 1 -> 100 us, 2 ->
> > 500 us, 3
> > -  -> 1 ms, 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms) recommended is
> > 2  
> > -- st,fraction-z: Length of the fractional part in z (fraction-z ([0..7]) =
> > Count of
> > -  the fractional part) recommended is 7
> > -- st,i-drive: current limit value of the touchscreen drivers (0 -> 20 mA
> > typical 35
> > -  mA max, 1 -> 50 mA typical 80 mA max)
> > +- st,ave-ctrl		: Sample average control
> > +				0 -> 1 sample
> > +				1 -> 2 samples
> > +				2 -> 4 samples
> > +				3 -> 8 samples
> > +- st,touch-det-delay	: Touch detect interrupt delay (recommended is
> > 3)
> > +				0 -> 10 us		5 -> 5 ms
> > +				1 -> 50 us		6 -> 10 ms
> > +				2 -> 100 us		7 -> 50 ms
> > +				3 -> 500 us
> > +				4-> 1 ms
> > +- st,settling		: Panel driver settling time (recommended is 2)
> > +				0 -> 10 us		5 -> 10 ms
> > +				1 -> 100 us		6 for 50 ms
> > +				2 -> 500 us		7 -> 100 ms
> > +				3 -> 1 ms
> > +				4 -> 5 ms
> > +- st,fraction-z		: Length of the fractional part in z
> > (recommended is 7)
> > +			  (fraction-z ([0..7]) = Count of the fractional part)
> > +- st,i-drive		: current limit value of the touchscreen drivers
> > +				0 -> 20 mA (typical 35mA max)
> > +				1 -> 50 mA (typical 80 mA max)
> > +
> > +Optional properties common with MFD (deprecated):
> > + - st,sample-time	: ADC conversion time in number of clock.
> > +				0 -> 36 clocks		4 -> 80 clocks
> > (recommended)
> > +				1 -> 44 clocks		5 -> 96 clocks
> > +				2 -> 56 clocks		6 -> 124 clocks
> > +				3 -> 64 clocks
> > + - st,mod-12b		: ADC Bit mode
> > +				0 -> 10bit ADC		1 -> 12bit ADC
> > + - st,ref-sel		: ADC reference source
> > +				0 -> internal		1 -> external
> > + - st,adc-freq		: ADC Clock speed
> > +				0 -> 1.625 MHz		2 || 3 -> 6.5 MHz
> > +				1 -> 3.25 MHz
> >  
> >  Node name must be stmpe_touchscreen and should be child node of stmpe node
> > to
> >  which it belongs.
> >  
> > +Note that common ADC settings of stmpe_touchscreen will take precedence.
> > +
> >  Example:
> >  
> >  	stmpe_touchscreen {
> >  		compatible = "st,stmpe-ts";
> > -		st,sample-time = <4>;
> > -		st,mod-12b = <1>;
> > -		st,ref-sel = <0>;
> > -		st,adc-freq = <1>;
> >  		st,ave-ctrl = <1>;
> >  		st,touch-det-delay = <2>;
> >  		st,settling = <2>;
> > diff --git a/Documentation/devicetree/bindings/mfd/stmpe.txt
> > b/Documentation/devicetree/bindings/mfd/stmpe.txt
> > index c797c05cd3c2..d4408a417193 100644
> > --- a/Documentation/devicetree/bindings/mfd/stmpe.txt
> > +++ b/Documentation/devicetree/bindings/mfd/stmpe.txt
> > @@ -4,15 +4,29 @@ STMPE is an MFD device which may expose the following
> > inbuilt devices: gpio,
> >  keypad, touchscreen, adc, pwm, rotator.
> >  
> >  Required properties:
> > - - compatible                   :
> > "st,stmpe[610|801|811|1600|1601|2401|2403]"
> > - - reg                          : I2C/SPI address of the device
> > + - compatible			:
> > "st,stmpe[610|801|811|1600|1601|2401|2403]"
> > + - reg				: I2C/SPI address of the device
> 
> Nothing wrong with correcting alignment, but it shouldn't be in the same patch
> as a fundamental change lie this.  Just adds noise.
> 
> If that means you first have to introduce the new block missaligned, then
> fix up the alignment in a follow up patch, then do that as we can then
> effectively ignore the realignment as obviously correct and focus on
> the real changes.
> 
> >  
> >  Optional properties:
> > - - interrupts                   : The interrupt outputs from the controller
> > - - interrupt-controller         : Marks the device node as an interrupt
> > controller
> > - - wakeup-source                : Marks the input device as wakable
> > - - st,autosleep-timeout         : Valid entries (ms); 4, 16, 32, 64, 128,
> > 256, 512 and 1024
> > - - irq-gpio                     : If present, which GPIO to use for event
> > IRQ
> > + - interrupts			: The interrupt outputs from the
> > controller
> > + - interrupt-controller		: Marks the device node as an interrupt
> > controller
> > + - wakeup-source		: Marks the input device as wakable
> > + - st,autosleep-timeout		: Valid entries (ms); 4, 16, 32, 64,
> > 128, 256, 512 and 1024
> > + - irq-gpio			: If present, which GPIO to use for
> > event IRQ
> > +
> > +Optional properties for devices with touch and ADC (STMPE811|STMPE610):
> > + - st,sample-time		: ADC conversion time in number of clock.
> > +					0 -> 36 clocks		4 -> 80
> > clocks (recommended)
> > +					1 -> 44 clocks		5 -> 96
> > clocks
> > +					2 -> 56 clocks		6 -> 124
> > clocks
> > +					3 -> 64 clocks
> > + - st,mod-12b			: ADC Bit mode
> > +					0 -> 10bit ADC		1 -> 12bit
> > ADC
> > + - st,ref-sel			: ADC reference source
> > +					0 -> internal		1 ->
> > external
> > + - st,adc-freq			: ADC Clock speed
> > +					0 -> 1.625 MHz		2 || 3 ->
> > 6.5 MHz
> > +					1 -> 3.25 MHz
> >  
> >  Example:
> >