diff mbox

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

Message ID 20170121144212.8858-1-marek.vasut@gmail.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show

Commit Message

Marek Vasut Jan. 21, 2017, 2:42 p.m. UTC
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.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: linux-renesas-soc@vger.kernel.org
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
---
 .../bindings/iio/adc/renesas,gyroadc.txt           | 93 ++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt

Comments

Rob Herring Jan. 23, 2017, 5:08 p.m. UTC | #1
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@gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Jonathan Cameron <jic23@kernel.org>
> Cc: linux-renesas-soc@vger.kernel.org
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.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
>
Marek Vasut Jan. 23, 2017, 7:56 p.m. UTC | #2
On 01/23/2017 06:08 PM, Rob Herring wrote:
> 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?

Technically yes, it was part of the 2/2 until now.

>> Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
>> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
>> Cc: Simon Horman <horms+renesas@verge.net.au>
>> Cc: Jonathan Cameron <jic23@kernel.org>
>> Cc: linux-renesas-soc@vger.kernel.org
>> Cc: Wolfram Sang <wsa@the-dreams.de>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: devicetree@vger.kernel.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?

The GyroADC block is a reduced SPI block with up to 8 chipselect lines,
which supports the SPI protocol of a selected few SPI ADCs. The SPI ADCs
are sampled by the GyroADC block in a round-robin fashion and the result
presented in the GyroADC registers.

Good ?

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

It's enumerated below , the only special-case we handle at this point is
the r8a7792 , which has extra interrupt block which we don't use anyway,
but the driver disables those interrupts.

>> +		Use "renesas,r8a7792-gyroadc" for a GyroADC with interrupt
>> +		block found in R8A7792.

I can add .... otherwise use the matching SoC model in <chip> field.

>> +- 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?

1, up-to 4 or up-to 8, depending on the ADC you connect.

I guess it can be made mandatory as not having any ADC attached would
make it pretty pointless to enable this block in the first place ...

>> +
>> +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.

Dropped.

>> +
>> +		#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
>>
Geert Uytterhoeven Jan. 23, 2017, 8:41 p.m. UTC | #3
Hi Marek,

On Mon, Jan 23, 2017 at 8:56 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
> On 01/23/2017 06:08 PM, Rob Herring wrote:
>> On Sat, Jan 21, 2017 at 03:42:11PM +0100, Marek Vasut wrote:
>>> new file mode 100644
>>> index 000000000000..081947367135
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt

>>> +Required properties:
>>> +- compatible:       Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>
>> Need to enumerate <chip>.
>
> It's enumerated below , the only special-case we handle at this point is
> the r8a7792 , which has extra interrupt block which we don't use anyway,
> but the driver disables those interrupts.

It is not enumerated below. You just give an example for r8a7791.

Please list all supported/tested compatible values, so checkpatch
can validate compatible values in DTS patches adding GyroADC device
nodes.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Marek Vasut Jan. 23, 2017, 11:15 p.m. UTC | #4
On 01/23/2017 09:41 PM, Geert Uytterhoeven wrote:
> Hi Marek,
> 
> On Mon, Jan 23, 2017 at 8:56 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
>> On 01/23/2017 06:08 PM, Rob Herring wrote:
>>> On Sat, Jan 21, 2017 at 03:42:11PM +0100, Marek Vasut wrote:
>>>> new file mode 100644
>>>> index 000000000000..081947367135
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
> 
>>>> +Required properties:
>>>> +- compatible:       Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>>
>>> Need to enumerate <chip>.
>>
>> It's enumerated below , the only special-case we handle at this point is
>> the r8a7792 , which has extra interrupt block which we don't use anyway,
>> but the driver disables those interrupts.
> 
> It is not enumerated below. You just give an example for r8a7791.
> 
> Please list all supported/tested compatible values, so checkpatch
> can validate compatible values in DTS patches adding GyroADC device
> nodes.

What about this ?

- compatible:   Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
                The <chip> can be either of:
                r8a7791 - for the GyroADC block present in r8a7791 SoC
                r8a7792 - for the GyroADC with interrupt block present
                          in r8a7792 SoC
Geert Uytterhoeven Jan. 24, 2017, 7:30 a.m. UTC | #5
Hi Marek,

On Tue, Jan 24, 2017 at 12:15 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> On 01/23/2017 09:41 PM, Geert Uytterhoeven wrote:
>> On Mon, Jan 23, 2017 at 8:56 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
>>> On 01/23/2017 06:08 PM, Rob Herring wrote:
>>>> On Sat, Jan 21, 2017 at 03:42:11PM +0100, Marek Vasut wrote:
>>>>> new file mode 100644
>>>>> index 000000000000..081947367135
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
>>
>>>>> +Required properties:
>>>>> +- compatible:       Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>>>
>>>> Need to enumerate <chip>.
>>>
>>> It's enumerated below , the only special-case we handle at this point is
>>> the r8a7792 , which has extra interrupt block which we don't use anyway,
>>> but the driver disables those interrupts.
>>
>> It is not enumerated below. You just give an example for r8a7791.
>>
>> Please list all supported/tested compatible values, so checkpatch
>> can validate compatible values in DTS patches adding GyroADC device
>> nodes.
>
> What about this ?
>
> - compatible:   Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>                 The <chip> can be either of:
>                 r8a7791 - for the GyroADC block present in r8a7791 SoC
>                 r8a7792 - for the GyroADC with interrupt block present
>                           in r8a7792 SoC

No, we need the exact string in the document, cfr. all other Renesas bindings.

"renesas,r8a7791-gyroadc"
"renesas,r8a7792-gyroadc"

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Marek Vasut Jan. 24, 2017, 4:39 p.m. UTC | #6
On 01/24/2017 08:30 AM, Geert Uytterhoeven wrote:
> Hi Marek,
> 
> On Tue, Jan 24, 2017 at 12:15 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
>> On 01/23/2017 09:41 PM, Geert Uytterhoeven wrote:
>>> On Mon, Jan 23, 2017 at 8:56 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
>>>> On 01/23/2017 06:08 PM, Rob Herring wrote:
>>>>> On Sat, Jan 21, 2017 at 03:42:11PM +0100, Marek Vasut wrote:
>>>>>> new file mode 100644
>>>>>> index 000000000000..081947367135
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
>>>
>>>>>> +Required properties:
>>>>>> +- compatible:       Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>>>>
>>>>> Need to enumerate <chip>.
>>>>
>>>> It's enumerated below , the only special-case we handle at this point is
>>>> the r8a7792 , which has extra interrupt block which we don't use anyway,
>>>> but the driver disables those interrupts.
>>>
>>> It is not enumerated below. You just give an example for r8a7791.
>>>
>>> Please list all supported/tested compatible values, so checkpatch
>>> can validate compatible values in DTS patches adding GyroADC device
>>> nodes.
>>
>> What about this ?
>>
>> - compatible:   Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>                 The <chip> can be either of:
>>                 r8a7791 - for the GyroADC block present in r8a7791 SoC
>>                 r8a7792 - for the GyroADC with interrupt block present
>>                           in r8a7792 SoC
> 
> No, we need the exact string in the document, cfr. all other Renesas bindings.
> 
> "renesas,r8a7791-gyroadc"
> "renesas,r8a7792-gyroadc"

This ?

- compatible:   Should be "<soc-specific>", "renesas,rcar-gyroadc".
                The <soc-specific> should be one of:
                renesas,r8a7791-gyroadc - for the GyroADC block present
                                          in r8a7791 SoC
                renesas,r8a7792-gyroadc - for the GyroADC with interrupt
                                          block present in r8a7792 SoC
Geert Uytterhoeven Jan. 24, 2017, 6:19 p.m. UTC | #7
Hi Marek,

On Tue, Jan 24, 2017 at 5:39 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
> On 01/24/2017 08:30 AM, Geert Uytterhoeven wrote:
>> On Tue, Jan 24, 2017 at 12:15 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
>>> What about this ?
>>>
>>> - compatible:   Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
>>>                 The <chip> can be either of:
>>>                 r8a7791 - for the GyroADC block present in r8a7791 SoC
>>>                 r8a7792 - for the GyroADC with interrupt block present
>>>                           in r8a7792 SoC
>>
>> No, we need the exact string in the document, cfr. all other Renesas bindings.
>>
>> "renesas,r8a7791-gyroadc"
>> "renesas,r8a7792-gyroadc"
>
> This ?
>
> - compatible:   Should be "<soc-specific>", "renesas,rcar-gyroadc".
>                 The <soc-specific> should be one of:
>                 renesas,r8a7791-gyroadc - for the GyroADC block present
>                                           in r8a7791 SoC
>                 renesas,r8a7792-gyroadc - for the GyroADC with interrupt
>                                           block present in r8a7792 SoC

Yes. I had expected that double quotes were mandatory, but apparently
checkpatch doesn't require that.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
diff mbox

Patch

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