iio: Add binding documentation for imx25 GCQ

The documentation describes the bindings for the imx25 GCQ unit which is
essentially a generic conversion queue using the imx25 ADC.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Markus Pargmann 2015-12-14 14:53:48 +01:00 committed by Lee Jones
parent 43de29baa9
commit 337600fbee
2 changed files with 76 additions and 0 deletions

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Freescale i.MX25 ADC GCQ device
This is a generic conversion queue device that can convert any of the
analog inputs using the ADC unit of the i.MX25.
Required properties:
- compatible: Should be "fsl,imx25-gcq".
- reg: Should be the register range of the module.
- interrupts: Should be the interrupt number of the module.
Typically this is <1>.
- interrupt-parent: phandle to the tsadc module of the i.MX25.
- #address-cells: Should be <1> (setting for the subnodes)
- #size-cells: Should be <0> (setting for the subnodes)
Optional properties:
- vref-ext-supply: The regulator supplying the ADC reference voltage.
Required when at least one subnode uses the this reference.
- vref-xp-supply: The regulator supplying the ADC reference voltage on pin XP.
Required when at least one subnode uses this reference.
- vref-yp-supply: The regulator supplying the ADC reference voltage on pin YP.
Required when at least one subnode uses this reference.
Sub-nodes:
Optionally you can define subnodes which define the reference voltage
for the analog inputs.
Required properties for subnodes:
- reg: Should be the number of the analog input.
0: xp
1: yp
2: xn
3: yn
4: wiper
5: inaux0
6: inaux1
7: inaux2
Optional properties for subnodes:
- fsl,adc-refp: specifies the positive reference input as defined in
<dt-bindings/iio/adc/fsl-imx25-gcq.h>
- fsl,adc-refn: specifies the negative reference input as defined in
<dt-bindings/iio/adc/fsl-imx25-gcq.h>
Example:
adc: adc@50030800 {
compatible = "fsl,imx25-gcq";
reg = <0x50030800 0x60>;
interrupt-parent = <&tscadc>;
interrupts = <1>;
#address-cells = <1>;
#size-cells = <0>;
inaux@5 {
reg = <5>;
fsl,adc-refp = <MX25_ADC_REFP_INT>;
fsl,adc-refn = <MX25_ADC_REFN_NGND>;
};
};

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/*
* This header provides constants for configuring the I.MX25 ADC
*/
#ifndef _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
#define _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
#define MX25_ADC_REFP_YP 0 /* YP voltage reference */
#define MX25_ADC_REFP_XP 1 /* XP voltage reference */
#define MX25_ADC_REFP_EXT 2 /* External voltage reference */
#define MX25_ADC_REFP_INT 3 /* Internal voltage reference */
#define MX25_ADC_REFN_XN 0 /* XN ground reference */
#define MX25_ADC_REFN_YN 1 /* YN ground reference */
#define MX25_ADC_REFN_NGND 2 /* Internal ground reference */
#define MX25_ADC_REFN_NGND2 3 /* External ground reference */
#endif