DT: iio: vadc: document dt binding

Document DT binding for Qualcomm SPMI PMIC voltage ADC
driver.

Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Stanimir Varbanov 2015-01-20 12:15:21 +02:00 committed by Jonathan Cameron
parent 2d8339d0ec
commit d3ba5586fa
2 changed files with 248 additions and 0 deletions

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Qualcomm's SPMI PMIC voltage ADC
SPMI PMIC voltage ADC (VADC) provides interface to clients to read
voltage. The VADC is a 15-bit sigma-delta ADC.
VADC node:
- compatible:
Usage: required
Value type: <string>
Definition: Should contain "qcom,spmi-vadc".
- reg:
Usage: required
Value type: <prop-encoded-array>
Definition: VADC base address and length in the SPMI PMIC register map.
- #address-cells:
Usage: required
Value type: <u32>
Definition: Must be one. Child node 'reg' property should define ADC
channel number.
- #size-cells:
Usage: required
Value type: <u32>
Definition: Must be zero.
- #io-channel-cells:
Usage: required
Value type: <u32>
Definition: Must be one. For details about IIO bindings see:
Documentation/devicetree/bindings/iio/iio-bindings.txt
- interrupts:
Usage: optional
Value type: <prop-encoded-array>
Definition: End of conversion interrupt.
Channel node properties:
- reg:
Usage: required
Value type: <u32>
Definition: ADC channel number.
See include/dt-bindings/iio/qcom,spmi-vadc.h
- qcom,decimation:
Usage: optional
Value type: <u32>
Definition: This parameter is used to decrease ADC sampling rate.
Quicker measurements can be made by reducing decimation ratio.
Valid values are 512, 1024, 2048, 4096.
If property is not found, default value of 512 will be used.
- qcom,pre-scaling:
Usage: optional
Value type: <u32 array>
Definition: Used for scaling the channel input signal before the signal is
fed to VADC. The configuration for this node is to know the
pre-determined ratio and use it for post scaling. Select one from
the following options.
<1 1>, <1 3>, <1 4>, <1 6>, <1 20>, <1 8>, <10 81>, <1 10>
If property is not found default value depending on chip will be used.
- qcom,ratiometric:
Usage: optional
Value type: <empty>
Definition: Channel calibration type. If this property is specified
VADC will use the VDD reference (1.8V) and GND for channel
calibration. If property is not found, channel will be
calibrated with 0.625V and 1.25V reference channels, also
known as absolute calibration.
- qcom,hw-settle-time:
Usage: optional
Value type: <u32>
Definition: Time between AMUX getting configured and the ADC starting
conversion. Delay = 100us * (value) for value < 11, and
2ms * (value - 10) otherwise.
Valid values are: 0, 100, 200, 300, 400, 500, 600, 700, 800,
900 us and 1, 2, 4, 6, 8, 10 ms
If property is not found, channel will use 0us.
- qcom,avg-samples:
Usage: optional
Value type: <u32>
Definition: Number of samples to be used for measurement.
Averaging provides the option to obtain a single measurement
from the ADC that is an average of multiple samples. The value
selected is 2^(value).
Valid values are: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512
If property is not found, 1 sample will be used.
NOTE:
Following channels, also known as reference point channels, are used for
result calibration and their channel configuration nodes should be defined:
VADC_REF_625MV and/or VADC_SPARE1(based on PMIC version) VADC_REF_1250MV,
VADC_GND_REF and VADC_VDD_VADC.
Example:
/* VADC node */
pmic_vadc: vadc@3100 {
compatible = "qcom,spmi-vadc";
reg = <0x3100 0x100>;
interrupts = <0x0 0x31 0x0 IRQ_TYPE_EDGE_RISING>;
#address-cells = <1>;
#size-cells = <0>;
#io-channel-cells = <1>;
io-channel-ranges;
/* Channel node */
usb_id_nopull {
reg = <VADC_LR_MUX10_USB_ID>;
qcom,decimation = <512>;
qcom,ratiometric;
qcom,hw-settle-time = <200>;
qcom,avg-samples = <1>;
qcom,pre-scaling = <1 3>;
};
};
/* IIO client node */
usb {
io-channels = <&pmic_vadc VADC_LR_MUX10_USB_ID>;
io-channel-names = "vadc";
};

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/*
* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _DT_BINDINGS_QCOM_SPMI_VADC_H
#define _DT_BINDINGS_QCOM_SPMI_VADC_H
/* Voltage ADC channels */
#define VADC_USBIN 0x00
#define VADC_DCIN 0x01
#define VADC_VCHG_SNS 0x02
#define VADC_SPARE1_03 0x03
#define VADC_USB_ID_MV 0x04
#define VADC_VCOIN 0x05
#define VADC_VBAT_SNS 0x06
#define VADC_VSYS 0x07
#define VADC_DIE_TEMP 0x08
#define VADC_REF_625MV 0x09
#define VADC_REF_1250MV 0x0a
#define VADC_CHG_TEMP 0x0b
#define VADC_SPARE1 0x0c
#define VADC_SPARE2 0x0d
#define VADC_GND_REF 0x0e
#define VADC_VDD_VADC 0x0f
#define VADC_P_MUX1_1_1 0x10
#define VADC_P_MUX2_1_1 0x11
#define VADC_P_MUX3_1_1 0x12
#define VADC_P_MUX4_1_1 0x13
#define VADC_P_MUX5_1_1 0x14
#define VADC_P_MUX6_1_1 0x15
#define VADC_P_MUX7_1_1 0x16
#define VADC_P_MUX8_1_1 0x17
#define VADC_P_MUX9_1_1 0x18
#define VADC_P_MUX10_1_1 0x19
#define VADC_P_MUX11_1_1 0x1a
#define VADC_P_MUX12_1_1 0x1b
#define VADC_P_MUX13_1_1 0x1c
#define VADC_P_MUX14_1_1 0x1d
#define VADC_P_MUX15_1_1 0x1e
#define VADC_P_MUX16_1_1 0x1f
#define VADC_P_MUX1_1_3 0x20
#define VADC_P_MUX2_1_3 0x21
#define VADC_P_MUX3_1_3 0x22
#define VADC_P_MUX4_1_3 0x23
#define VADC_P_MUX5_1_3 0x24
#define VADC_P_MUX6_1_3 0x25
#define VADC_P_MUX7_1_3 0x26
#define VADC_P_MUX8_1_3 0x27
#define VADC_P_MUX9_1_3 0x28
#define VADC_P_MUX10_1_3 0x29
#define VADC_P_MUX11_1_3 0x2a
#define VADC_P_MUX12_1_3 0x2b
#define VADC_P_MUX13_1_3 0x2c
#define VADC_P_MUX14_1_3 0x2d
#define VADC_P_MUX15_1_3 0x2e
#define VADC_P_MUX16_1_3 0x2f
#define VADC_LR_MUX1_BAT_THERM 0x30
#define VADC_LR_MUX2_BAT_ID 0x31
#define VADC_LR_MUX3_XO_THERM 0x32
#define VADC_LR_MUX4_AMUX_THM1 0x33
#define VADC_LR_MUX5_AMUX_THM2 0x34
#define VADC_LR_MUX6_AMUX_THM3 0x35
#define VADC_LR_MUX7_HW_ID 0x36
#define VADC_LR_MUX8_AMUX_THM4 0x37
#define VADC_LR_MUX9_AMUX_THM5 0x38
#define VADC_LR_MUX10_USB_ID 0x39
#define VADC_AMUX_PU1 0x3a
#define VADC_AMUX_PU2 0x3b
#define VADC_LR_MUX3_BUF_XO_THERM 0x3c
#define VADC_LR_MUX1_PU1_BAT_THERM 0x70
#define VADC_LR_MUX2_PU1_BAT_ID 0x71
#define VADC_LR_MUX3_PU1_XO_THERM 0x72
#define VADC_LR_MUX4_PU1_AMUX_THM1 0x73
#define VADC_LR_MUX5_PU1_AMUX_THM2 0x74
#define VADC_LR_MUX6_PU1_AMUX_THM3 0x75
#define VADC_LR_MUX7_PU1_AMUX_HW_ID 0x76
#define VADC_LR_MUX8_PU1_AMUX_THM4 0x77
#define VADC_LR_MUX9_PU1_AMUX_THM5 0x78
#define VADC_LR_MUX10_PU1_AMUX_USB_ID 0x79
#define VADC_LR_MUX3_BUF_PU1_XO_THERM 0x7c
#define VADC_LR_MUX1_PU2_BAT_THERM 0xb0
#define VADC_LR_MUX2_PU2_BAT_ID 0xb1
#define VADC_LR_MUX3_PU2_XO_THERM 0xb2
#define VADC_LR_MUX4_PU2_AMUX_THM1 0xb3
#define VADC_LR_MUX5_PU2_AMUX_THM2 0xb4
#define VADC_LR_MUX6_PU2_AMUX_THM3 0xb5
#define VADC_LR_MUX7_PU2_AMUX_HW_ID 0xb6
#define VADC_LR_MUX8_PU2_AMUX_THM4 0xb7
#define VADC_LR_MUX9_PU2_AMUX_THM5 0xb8
#define VADC_LR_MUX10_PU2_AMUX_USB_ID 0xb9
#define VADC_LR_MUX3_BUF_PU2_XO_THERM 0xbc
#define VADC_LR_MUX1_PU1_PU2_BAT_THERM 0xf0
#define VADC_LR_MUX2_PU1_PU2_BAT_ID 0xf1
#define VADC_LR_MUX3_PU1_PU2_XO_THERM 0xf2
#define VADC_LR_MUX4_PU1_PU2_AMUX_THM1 0xf3
#define VADC_LR_MUX5_PU1_PU2_AMUX_THM2 0xf4
#define VADC_LR_MUX6_PU1_PU2_AMUX_THM3 0xf5
#define VADC_LR_MUX7_PU1_PU2_AMUX_HW_ID 0xf6
#define VADC_LR_MUX8_PU1_PU2_AMUX_THM4 0xf7
#define VADC_LR_MUX9_PU1_PU2_AMUX_THM5 0xf8
#define VADC_LR_MUX10_PU1_PU2_AMUX_USB_ID 0xf9
#define VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM 0xfc
#endif /* _DT_BINDINGS_QCOM_SPMI_VADC_H */