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iio: adc: Add Renesas GyroADC bindings

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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+renesas@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>
Acked-by: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Marek Vasut 2017-01-28 00:08:36 +01:00 committed by Jonathan Cameron
parent 63d8d50ce3
commit ec2ef15335
1 changed files with 99 additions and 0 deletions
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Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt Normal file
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* Renesas RCar GyroADC device driver
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.
Required properties:
- 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
- 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:
You must define subnode(s) 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@e6e54000 {
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";
#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>;
};
};