Re: [PATCH 1/2] iio: adc: Add Renesas GyroADC bindings

[Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Sat, Jan 21, 2017 at 03:42:11PM +0100, Marek Vasut wrote:
> Add DT bindings for the Renesas RCar GyroADC block. This block is
> a simple 4/8-channel ADC which samples 12/15/24 bits of data every
> cycle from all channels.

Isn't this v7?

> 
> Signed-off-by: Marek Vasut <marek.vasut-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Cc: Geert Uytterhoeven <geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
> Cc: Simon Horman <horms+renesas-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>
> Cc: Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: linux-renesas-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Cc: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
> Cc: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  .../bindings/iio/adc/renesas,gyroadc.txt           | 93 ++++++++++++++++++++++
>  1 file changed, 93 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
> new file mode 100644
> index 000000000000..081947367135
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
> @@ -0,0 +1,93 @@
> +* Renesas RCar GyroADC device driver

What's a GyroADC?

> +
> +Required properties:
> +- compatible:	Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".

Need to enumerate <chip>.

> +		Use "renesas,r8a7792-gyroadc" for a GyroADC with interrupt
> +		block found in R8A7792.
> +- reg:		Address and length of the register set for the device
> +- clocks:	References to all the clocks specified in the clock-names
> +		property as specified in
> +		Documentation/devicetree/bindings/clock/clock-bindings.txt.
> +- clock-names:	Shall contain "fck" and "if". The "fck" is the GyroADC block
> +		clock, the "if" is the interface clock.
> +- power-domains: Must contain a reference to the PM domain, if available.
> +- #address-cells: Should be <1> (setting for the subnodes) for all ADCs
> +		except for "fujitsu,mb88101a". Should be <0> (setting for
> +		only subnode) for "fujitsu,mb88101a".
> +- #size-cells:	Should be <0> (setting for the subnodes)
> +
> +Sub-nodes:
> +Optionally you can define subnodes which select the connected ADC type and
> +reference voltage for the GyroADC channels.

Seems strange to be optional. How many nodes are possible?

> +
> +Required properties for subnodes:
> +- compatible:	Should be either of:
> +		"fujitsu,mb88101a"
> +			- Fujitsu MB88101A compatible mode,
> +			  12bit sampling, up to 4 channels can be sampled in
> +			  round-robin fashion. One Fujitsu chip supplies four
> +			  GyroADC channels with data as it contains four ADCs
> +			  on the chip and thus for 4-channel operation, single
> +			  MB88101A is required. The Cx chipselect lines of the
> +			  MB88101A connect directly to two CHS lines of the
> +			  GyroADC, no demuxer is required. The data out line
> +			  of each MB88101A connects to a shared input pin of
> +			  the GyroADC.
> +		"ti,adcs7476" or "ti,adc121" or "adi,ad7476"
> +			- TI ADCS7476 / TI ADC121 / ADI AD7476 compatible mode,
> +			  15bit sampling, up to 8 channels can be sampled in
> +			  round-robin fashion. One TI/ADI chip supplies single
> +			  ADC channel with data, thus for 8-channel operation,
> +			  8 chips are required. A 3:8 chipselect demuxer is
> +			  required to connect the nCS line of the TI/ADI chips
> +			  to the GyroADC, while MISO line of each TI/ADI ADC
> +			  connects to a shared input pin of the GyroADC.
> +		"maxim,max1162" or "maxim,max11100"
> +			- Maxim MAX1162 / Maxim MAX11100 compatible mode,
> +			  16bit sampling, up to 8 channels can be sampled in
> +			  round-robin fashion. One Maxim chip supplies single
> +			  ADC channel with data, thus for 8-channel operation,
> +			  8 chips are required. A 3:8 chipselect demuxer is
> +			  required to connect the nCS line of the MAX chips
> +			  to the GyroADC, while MISO line of each Maxim ADC
> +			  connects to a shared input pin of the GyroADC.
> +- reg:		Should be the number of the analog input. Should be present
> +		for all ADCs except "fujitsu,mb88101a".
> +- vref-supply:	Reference to the channel reference voltage regulator.
> +
> +Example:
> +	vref_max1162: regulator-vref-max1162 {
> +		compatible = "regulator-fixed";
> +
> +		regulator-name = "MAX1162 Vref";
> +		regulator-min-microvolt = <4096000>;
> +		regulator-max-microvolt = <4096000>;
> +	};
> +
> +	&adc {
> +		compatible = "renesas,r8a7791-gyroadc", "renesas,rcar-gyroadc";
> +		reg = <0 0xe6e54000 0 64>;
> +		clocks = <&mstp9_clks R8A7791_CLK_GYROADC>, <&clk_65m>;
> +		clock-names = "fck", "if";
> +		power-domains = <&sysc R8A7791_PD_ALWAYS_ON>;
> +
> +		pinctrl-0 = <&adc_pins>;
> +		pinctrl-names = "default";
> +
> +		status = "okay";

Drop status from examples.

> +
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		adc@0 {
> +			reg = <0>;
> +			compatible = "maxim,max1162";
> +			vref-supply = <&vref_max1162>;
> +		};
> +
> +		adc@1 {
> +			reg = <1>;
> +			compatible = "maxim,max1162";
> +			vref-supply = <&vref_max1162>;
> +		};
> +	};
> -- 
> 2.11.0
>