[PATCH v5 0/2] Initial support for voltage ADC

[PATCH v5 0/2] Initial support for voltage ADC

[Ivan T. Ivanov]

This type of volatage ADC could be found in Qualcomm's SPMI PMIC's.
I'm sorry that it took me so long to send the updated version.

Changes since v4.
- Addressed review comments from Hartmut Knaack and Jonathan Cameron:
  Fixed spelling errors in DT description files.
  Removed unused structure member.
  Access to hardware during conversion is protected with mutex.
  Measuring reference points moved at driver probe time.

Patches are based on current iio/testing branch.

v4 could be found here: https://lkml.org/lkml/2014/11/3/425

Stanimir Varbanov (2):
  DT: iio: vadc: document dt binding
  iio: vadc: Qualcomm SPMI PMIC voltage ADC driver

 .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt |  129 +++
 drivers/iio/adc/Kconfig                            |   14 +
 drivers/iio/adc/Makefile                           |    1 +
 drivers/iio/adc/qcom-spmi-vadc.c                   | 1016 ++++++++++++++++++++
 include/dt-bindings/iio/qcom,spmi-vadc.h           |  119 +++
 5 files changed, 1279 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
 create mode 100644 drivers/iio/adc/qcom-spmi-vadc.c
 create mode 100644 include/dt-bindings/iio/qcom,spmi-vadc.h

--
1.9.1

[PATCH v5 1/2] DT: iio: vadc: document dt binding

[Ivan T. Ivanov]

From: Stanimir Varbanov <svarbanov@mm-sol.com>

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>
---
 .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt | 129 +++++++++++++++++++++
 include/dt-bindings/iio/qcom,spmi-vadc.h           | 119 +++++++++++++++++++
 2 files changed, 248 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
 create mode 100644 include/dt-bindings/iio/qcom,spmi-vadc.h

diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
new file mode 100644
index 0000000..0fb4613
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
@@ -0,0 +1,129 @@
+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";
+	};
diff --git a/include/dt-bindings/iio/qcom,spmi-vadc.h b/include/dt-bindings/iio/qcom,spmi-vadc.h
new file mode 100644
index 0000000..42121fa
--- /dev/null
+++ b/include/dt-bindings/iio/qcom,spmi-vadc.h
@@ -0,0 +1,119 @@
+/*
+ * 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 */
--
1.9.1

[PATCH v5 2/2] iio: vadc: Qualcomm SPMI PMIC voltage ADC driver

[Ivan T. Ivanov]

From: Stanimir Varbanov <svarbanov@mm-sol.com>

The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
15bits resolution and register space inside PMIC accessible across
SPMI bus.

The vadc driver registers itself through IIO interface.

Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
---
 drivers/iio/adc/Kconfig          |   14 +
 drivers/iio/adc/Makefile         |    1 +
 drivers/iio/adc/qcom-spmi-vadc.c | 1016 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 1031 insertions(+)
 create mode 100644 drivers/iio/adc/qcom-spmi-vadc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index d0924f3..792e2b8 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -220,6 +220,20 @@ config QCOM_SPMI_IADC
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-spmi-iadc.

+config QCOM_SPMI_VADC
+	tristate "Qualcomm SPMI PMIC voltage ADC"
+	depends on SPMI
+	select REGMAP_SPMI
+	help
+	  This is the IIO Voltage ADC driver for Qualcomm QPNP VADC Chip.
+
+	  The driver supports multiple channels read. The VADC is a 15-bit
+	  sigma-delta ADC. Some of the channels are internally used for
+	  calibration.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called qcom-spmi-vadc.
+
 config ROCKCHIP_SARADC
 	tristate "Rockchip SARADC driver"
 	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index c06718b..285b0a0 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
+obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
 obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
new file mode 100644
index 0000000..3211729
--- /dev/null
+++ b/drivers/iio/adc/qcom-spmi-vadc.c
@@ -0,0 +1,1016 @@
+/*
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+
+#include <dt-bindings/iio/qcom,spmi-vadc.h>
+
+/* VADC register and bit definitions */
+#define VADC_REVISION2				0x1
+#define VADC_REVISION2_SUPPORTED_VADC		1
+
+#define VADC_PERPH_TYPE				0x4
+#define VADC_PERPH_TYPE_ADC			8
+
+#define VADC_PERPH_SUBTYPE			0x5
+#define VADC_PERPH_SUBTYPE_VADC			1
+
+#define VADC_STATUS1				0x8
+#define VADC_STATUS1_OP_MODE			4
+#define VADC_STATUS1_REQ_STS			BIT(1)
+#define VADC_STATUS1_EOC			BIT(0)
+#define VADC_STATUS1_REQ_STS_EOC_MASK		0x3
+
+#define VADC_MODE_CTL				0x40
+#define VADC_OP_MODE_SHIFT			3
+#define VADC_OP_MODE_NORMAL			0
+#define VADC_AMUX_TRIM_EN			BIT(1)
+#define VADC_ADC_TRIM_EN			BIT(0)
+
+#define VADC_EN_CTL1				0x46
+#define VADC_EN_CTL1_SET			BIT(7)
+
+#define VADC_ADC_CH_SEL_CTL			0x48
+
+#define VADC_ADC_DIG_PARAM			0x50
+#define VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT	2
+
+#define VADC_HW_SETTLE_DELAY			0x51
+
+#define VADC_CONV_REQ				0x52
+#define VADC_CONV_REQ_SET			BIT(7)
+
+#define VADC_FAST_AVG_CTL			0x5a
+#define VADC_FAST_AVG_EN			0x5b
+#define VADC_FAST_AVG_EN_SET			BIT(7)
+
+#define VADC_ACCESS				0xd0
+#define VADC_ACCESS_DATA			0xa5
+
+#define VADC_PERH_RESET_CTL3			0xda
+#define VADC_FOLLOW_WARM_RB			BIT(2)
+
+#define VADC_DATA				0x60	/* 16 bits */
+
+#define VADC_CONV_TIME_MIN_US			2000
+#define VADC_CONV_TIME_MAX_US			2100
+
+/* Min ADC code represents 0V */
+#define VADC_MIN_ADC_CODE			0x6000
+/* Max ADC code represents full-scale range of 1.8V */
+#define VADC_MAX_ADC_CODE			0xa800
+
+#define VADC_ABSOLUTE_RANGE_UV			625000
+#define VADC_RATIOMETRIC_RANGE_UV		1800000
+
+#define VADC_DEF_PRESCALING			0 /* 1:1 */
+#define VADC_DEF_DECIMATION			0 /* 512 */
+#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */
+#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */
+#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE
+
+#define VADC_DECIMATION_MIN			512
+#define VADC_DECIMATION_MAX			4096
+
+#define VADC_HW_SETTLE_DELAY_MAX		10000
+#define VADC_AVG_SAMPLES_MAX			512
+
+#define KELVINMIL_CELSIUSMIL			273150
+
+#define VADC_CHAN_MIN			VADC_USBIN
+#define VADC_CHAN_MAX			VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
+
+/*
+ * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
+ * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
+ * calibration.
+ */
+enum vadc_calibration {
+	VADC_CALIB_ABSOLUTE = 0,
+	VADC_CALIB_RATIOMETRIC
+};
+
+/**
+ * struct vadc_linear_graph - Represent ADC characteristics.
+ * @dy: numerator slope to calculate the gain.
+ * @dx: denominator slope to calculate the gain.
+ * @gnd: A/D word of the ground reference used for the channel.
+ *
+ * Each ADC device has different offset and gain parameters which are
+ * computed to calibrate the device.
+ */
+struct vadc_linear_graph {
+	s32 dy;
+	s32 dx;
+	s32 gnd;
+};
+
+/**
+ * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
+ * @num: the inverse numerator of the gain applied to the input channel.
+ * @den: the inverse denominator of the gain applied to the input channel.
+ */
+struct vadc_prescale_ratio {
+	u32 num;
+	u32 den;
+};
+
+/**
+ * struct vadc_channel_prop - VADC channel property.
+ * @channel: channel number, refer to the channel list.
+ * @calibration: calibration type.
+ * @decimation: sampling rate supported for the channel.
+ * @prescale: channel scaling performed on the input signal.
+ * @hw_settle_time: the time between AMUX being configured and the
+ *	start of conversion.
+ * @avg_samples: ability to provide single result from the ADC
+ *	that is an average of multiple measurements.
+ */
+struct vadc_channel_prop {
+	unsigned int channel;
+	enum vadc_calibration calibration;
+	unsigned int decimation;
+	unsigned int prescale;
+	unsigned int hw_settle_time;
+	unsigned int avg_samples;
+};
+
+/**
+ * struct vadc_priv - VADC private structure.
+ * @regmap: pointer to struct regmap.
+ * @dev: pointer to struct device.
+ * @base: base address for the ADC peripheral.
+ * @nchannels: number of VADC channels.
+ * @chan_props: array of VADC channel properties.
+ * @iio_chans: array of IIO channels specification.
+ * @are_ref_measured: are reference points measured.
+ * @poll_eoc: use polling instead of interrupt.
+ * @complete: VADC result notification after interrupt is received.
+ * @graph: store parameters for calibration.
+ * @lock: ADC lock for access to the peripheral.
+ */
+struct vadc_priv {
+	struct regmap		 *regmap;
+	struct device		 *dev;
+	u16			 base;
+	unsigned int		 nchannels;
+	struct vadc_channel_prop *chan_props;
+	struct iio_chan_spec	 *iio_chans;
+	bool			 are_ref_measured;
+	bool			 poll_eoc;
+	struct completion	 complete;
+	struct vadc_linear_graph graph[2];
+	struct mutex		 lock;
+};
+
+static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
+	{.num =  1, .den =  1},
+	{.num =  1, .den =  3},
+	{.num =  1, .den =  4},
+	{.num =  1, .den =  6},
+	{.num =  1, .den = 20},
+	{.num =  1, .den =  8},
+	{.num = 10, .den = 81},
+	{.num =  1, .den = 10}
+};
+
+static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
+{
+	return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
+}
+
+static int vadc_write(struct vadc_priv *vadc, u16 offset, u8 data)
+{
+	return regmap_write(vadc->regmap, vadc->base + offset, data);
+}
+
+static int vadc_reset(struct vadc_priv *vadc)
+{
+	u8 data;
+	int ret;
+
+	ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
+	if (ret)
+		return ret;
+
+	ret = vadc_read(vadc, VADC_PERH_RESET_CTL3, &data);
+	if (ret)
+		return ret;
+
+	ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
+	if (ret)
+		return ret;
+
+	data |= VADC_FOLLOW_WARM_RB;
+
+	return vadc_write(vadc, VADC_PERH_RESET_CTL3, data);
+}
+
+static int vadc_set_state(struct vadc_priv *vadc, bool state)
+{
+	return vadc_write(vadc, VADC_EN_CTL1, state ? VADC_EN_CTL1_SET : 0);
+}
+
+static void vadc_show_status(struct vadc_priv *vadc)
+{
+	u8 mode, sta1, chan, dig, en, req;
+	int ret;
+
+	ret = vadc_read(vadc, VADC_MODE_CTL, &mode);
+	if (ret)
+		return;
+
+	ret = vadc_read(vadc, VADC_ADC_DIG_PARAM, &dig);
+	if (ret)
+		return;
+
+	ret = vadc_read(vadc, VADC_ADC_CH_SEL_CTL, &chan);
+	if (ret)
+		return;
+
+	ret = vadc_read(vadc, VADC_CONV_REQ, &req);
+	if (ret)
+		return;
+
+	ret = vadc_read(vadc, VADC_STATUS1, &sta1);
+	if (ret)
+		return;
+
+	ret = vadc_read(vadc, VADC_EN_CTL1, &en);
+	if (ret)
+		return;
+
+	dev_err(vadc->dev,
+		"mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n",
+		mode, en, chan, dig, req, sta1);
+}
+
+static int vadc_configure(struct vadc_priv *vadc,
+			  struct vadc_channel_prop *prop)
+{
+	u8 decimation, mode_ctrl;
+	int ret;
+
+	/* Mode selection */
+	mode_ctrl = (VADC_OP_MODE_NORMAL << VADC_OP_MODE_SHIFT) |
+		     VADC_ADC_TRIM_EN | VADC_AMUX_TRIM_EN;
+	ret = vadc_write(vadc, VADC_MODE_CTL, mode_ctrl);
+	if (ret)
+		return ret;
+
+	/* Channel selection */
+	ret = vadc_write(vadc, VADC_ADC_CH_SEL_CTL, prop->channel);
+	if (ret)
+		return ret;
+
+	/* Digital parameter setup */
+	decimation = prop->decimation << VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT;
+	ret = vadc_write(vadc, VADC_ADC_DIG_PARAM, decimation);
+	if (ret)
+		return ret;
+
+	/* HW settle time delay */
+	ret = vadc_write(vadc, VADC_HW_SETTLE_DELAY, prop->hw_settle_time);
+	if (ret)
+		return ret;
+
+	ret = vadc_write(vadc, VADC_FAST_AVG_CTL, prop->avg_samples);
+	if (ret)
+		return ret;
+
+	if (prop->avg_samples)
+		ret = vadc_write(vadc, VADC_FAST_AVG_EN, VADC_FAST_AVG_EN_SET);
+	else
+		ret = vadc_write(vadc, VADC_FAST_AVG_EN, 0);
+
+	return ret;
+}
+
+static int vadc_poll_wait_eoc(struct vadc_priv *vadc, unsigned int interval_us)
+{
+	unsigned int count, retry;
+	u8 sta1;
+	int ret;
+
+	retry = interval_us / VADC_CONV_TIME_MIN_US;
+
+	for (count = 0; count < retry; count++) {
+		ret = vadc_read(vadc, VADC_STATUS1, &sta1);
+		if (ret)
+			return ret;
+
+		sta1 &= VADC_STATUS1_REQ_STS_EOC_MASK;
+		if (sta1 == VADC_STATUS1_EOC)
+			return 0;
+
+		usleep_range(VADC_CONV_TIME_MIN_US, VADC_CONV_TIME_MAX_US);
+	}
+
+	vadc_show_status(vadc);
+
+	return -ETIMEDOUT;
+}
+
+static int vadc_read_result(struct vadc_priv *vadc, u16 *data)
+{
+	int ret;
+
+	ret = regmap_bulk_read(vadc->regmap, vadc->base + VADC_DATA, data, 2);
+	if (ret)
+		return ret;
+
+	*data = clamp_t(u16, *data, VADC_MIN_ADC_CODE, VADC_MAX_ADC_CODE);
+
+	return 0;
+}
+
+static struct vadc_channel_prop *vadc_get_channel(struct vadc_priv *vadc,
+						  unsigned int num)
+{
+	unsigned int i;
+
+	for (i = 0; i < vadc->nchannels; i++)
+		if (vadc->chan_props[i].channel == num)
+			return &vadc->chan_props[i];
+
+	dev_dbg(vadc->dev, "no such channel %02x\n", num);
+
+	return NULL;
+}
+
+static int vadc_do_conversion(struct vadc_priv *vadc,
+			      struct vadc_channel_prop *prop, u16 *data)
+{
+	unsigned int timeout;
+	int ret;
+
+	mutex_lock(&vadc->lock);
+
+	ret = vadc_configure(vadc, prop);
+	if (ret)
+		goto unlock;
+
+	if (!vadc->poll_eoc)
+		reinit_completion(&vadc->complete);
+
+	ret = vadc_set_state(vadc, true);
+	if (ret)
+		goto unlock;
+
+	ret = vadc_write(vadc, VADC_CONV_REQ, VADC_CONV_REQ_SET);
+	if (ret)
+		goto err_disable;
+
+	timeout = BIT(prop->avg_samples) * VADC_CONV_TIME_MIN_US * 2;
+
+	if (vadc->poll_eoc) {
+		ret = vadc_poll_wait_eoc(vadc, timeout);
+	} else {
+		ret = wait_for_completion_timeout(&vadc->complete, timeout);
+		if (!ret) {
+			ret = -ETIMEDOUT;
+			goto err_disable;
+		}
+
+		/* Double check conversion status */
+		ret = vadc_poll_wait_eoc(vadc, VADC_CONV_TIME_MIN_US);
+		if (ret)
+			goto err_disable;
+	}
+
+	ret = vadc_read_result(vadc, data);
+
+err_disable:
+	vadc_set_state(vadc, false);
+	if (ret)
+		dev_err(vadc->dev, "conversion failed\n");
+unlock:
+	mutex_unlock(&vadc->lock);
+	return ret;
+}
+
+static int vadc_measure_ref_points(struct vadc_priv *vadc)
+{
+	struct vadc_channel_prop *prop;
+	u16 read_1, read_2;
+	int ret;
+
+	vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE_UV;
+	vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
+
+	prop = vadc_get_channel(vadc, VADC_REF_1250MV);
+	ret = vadc_do_conversion(vadc, prop, &read_1);
+	if (ret)
+		goto err;
+
+	/* Try with buffered 625mV channel first */
+	prop = vadc_get_channel(vadc, VADC_SPARE1);
+	if (!prop)
+		prop = vadc_get_channel(vadc, VADC_REF_625MV);
+
+	ret = vadc_do_conversion(vadc, prop, &read_2);
+	if (ret)
+		goto err;
+
+	if (read_1 == read_2) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	vadc->graph[VADC_CALIB_ABSOLUTE].dy = read_1 - read_2;
+	vadc->graph[VADC_CALIB_ABSOLUTE].gnd = read_2;
+
+	/* Ratiometric calibration */
+	prop = vadc_get_channel(vadc, VADC_VDD_VADC);
+	ret = vadc_do_conversion(vadc, prop, &read_1);
+	if (ret)
+		goto err;
+
+	prop = vadc_get_channel(vadc, VADC_GND_REF);
+	ret = vadc_do_conversion(vadc, prop, &read_2);
+	if (ret)
+		goto err;
+
+	if (read_1 == read_2) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	vadc->graph[VADC_CALIB_RATIOMETRIC].dy = read_1 - read_2;
+	vadc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_2;
+err:
+	if (ret)
+		dev_err(vadc->dev, "measure reference points failed\n");
+
+	return ret;
+}
+
+static s32 vadc_calibrate(struct vadc_priv *vadc,
+			  const struct vadc_channel_prop *prop, u16 adc_code)
+{
+	const struct vadc_prescale_ratio *prescale;
+	s32 voltage;
+
+	voltage = adc_code - vadc->graph[prop->calibration].gnd;
+	voltage *= vadc->graph[prop->calibration].dx;
+	voltage = voltage / vadc->graph[prop->calibration].dy;
+
+	if (prop->calibration == VADC_CALIB_ABSOLUTE)
+		voltage += vadc->graph[prop->calibration].dx;
+
+	if (voltage < 0)
+		voltage = 0;
+
+	prescale = &vadc_prescale_ratios[prop->prescale];
+
+	voltage = voltage * prescale->den;
+
+	return voltage / prescale->num;
+}
+
+static int vadc_decimation_from_dt(u32 value)
+{
+	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
+	    value > VADC_DECIMATION_MAX)
+		return -EINVAL;
+
+	return __ffs64(value / VADC_DECIMATION_MIN);
+}
+
+static int vadc_prescaling_from_dt(u32 num, u32 den)
+{
+	unsigned int pre;
+
+	for (pre = 0; pre < ARRAY_SIZE(vadc_prescale_ratios); pre++)
+		if (vadc_prescale_ratios[pre].num == num &&
+		    vadc_prescale_ratios[pre].den == den)
+			break;
+
+	if (pre == ARRAY_SIZE(vadc_prescale_ratios))
+		return -EINVAL;
+
+	return pre;
+}
+
+static int vadc_hw_settle_time_from_dt(u32 value)
+{
+	if ((value <= 1000 && value % 100) || (value > 1000 && value % 2000))
+		return -EINVAL;
+
+	if (value <= 1000)
+		value /= 100;
+	else
+		value = value / 2000 + 10;
+
+	return value;
+}
+
+static int vadc_avg_samples_from_dt(u32 value)
+{
+	if (!is_power_of_2(value) || value > VADC_AVG_SAMPLES_MAX)
+		return -EINVAL;
+
+	return __ffs64(value);
+}
+
+static int vadc_read_raw(struct iio_dev *indio_dev,
+			 struct iio_chan_spec const *chan, int *val, int *val2,
+			 long mask)
+{
+	struct vadc_priv *vadc = iio_priv(indio_dev);
+	struct vadc_channel_prop *prop;
+	u16 adc_code;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		prop = &vadc->chan_props[chan->address];
+		ret = vadc_do_conversion(vadc, prop, &adc_code);
+		if (ret)
+			break;
+
+		*val = vadc_calibrate(vadc, prop, adc_code);
+
+		/* 2mV/K, return milli Celsius */
+		*val /= 2;
+		*val -= KELVINMIL_CELSIUSMIL;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_RAW:
+		prop = &vadc->chan_props[chan->address];
+		ret = vadc_do_conversion(vadc, prop, &adc_code);
+		if (ret)
+			break;
+
+		*val = vadc_calibrate(vadc, prop, adc_code);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int vadc_of_xlate(struct iio_dev *indio_dev,
+			 const struct of_phandle_args *iiospec)
+{
+	struct vadc_priv *vadc = iio_priv(indio_dev);
+	unsigned int i;
+
+	for (i = 0; i < vadc->nchannels; i++)
+		if (vadc->iio_chans[i].channel == iiospec->args[0])
+			return i;
+
+	return -EINVAL;
+}
+
+static const struct iio_info vadc_info = {
+	.read_raw = vadc_read_raw,
+	.of_xlate = vadc_of_xlate,
+	.driver_module = THIS_MODULE,
+};
+
+struct vadc_channels {
+	const char *datasheet_name;
+	unsigned int prescale_index;
+	enum iio_chan_type type;
+	long info_mask;
+};
+
+#define VADC_CHAN(_dname, _type, _mask, _pre)				\
+	[VADC_##_dname] = {						\
+		.datasheet_name = __stringify(_dname),			\
+		.prescale_index = _pre,					\
+		.type = _type,						\
+		.info_mask = _mask					\
+	},								\
+
+#define VADC_CHAN_TEMP(_dname, _pre)					\
+	VADC_CHAN(_dname, IIO_TEMP, BIT(IIO_CHAN_INFO_PROCESSED), _pre)	\
+
+#define VADC_CHAN_VOLT(_dname, _pre)					\
+	VADC_CHAN(_dname, IIO_VOLTAGE,					\
+		  BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),	\
+		  _pre)							\
+
+/*
+ * The array represents all possible ADC channels found in the supported PMICs.
+ * Every index in the array is equal to the channel number per datasheet. The
+ * gaps in the array should be treated as reserved channels.
+ */
+static const struct vadc_channels vadc_chans[] = {
+	VADC_CHAN_VOLT(USBIN, 4)
+	VADC_CHAN_VOLT(DCIN, 4)
+	VADC_CHAN_VOLT(VCHG_SNS, 3)
+	VADC_CHAN_VOLT(SPARE1_03, 1)
+	VADC_CHAN_VOLT(USB_ID_MV, 1)
+	VADC_CHAN_VOLT(VCOIN, 1)
+	VADC_CHAN_VOLT(VBAT_SNS, 1)
+	VADC_CHAN_VOLT(VSYS, 1)
+	VADC_CHAN_TEMP(DIE_TEMP, 0)
+	VADC_CHAN_VOLT(REF_625MV, 0)
+	VADC_CHAN_VOLT(REF_1250MV, 0)
+	VADC_CHAN_VOLT(CHG_TEMP, 0)
+	VADC_CHAN_VOLT(SPARE1, 0)
+	VADC_CHAN_VOLT(SPARE2, 0)
+	VADC_CHAN_VOLT(GND_REF, 0)
+	VADC_CHAN_VOLT(VDD_VADC, 0)
+
+	VADC_CHAN_VOLT(P_MUX1_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX2_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX3_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX4_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX5_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX6_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX7_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX8_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX9_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX10_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX11_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX12_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX13_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX14_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX15_1_1, 0)
+	VADC_CHAN_VOLT(P_MUX16_1_1, 0)
+
+	VADC_CHAN_VOLT(P_MUX1_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX2_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX3_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX4_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX5_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX6_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX7_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX8_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX9_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX10_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX11_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX12_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX13_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX14_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX15_1_3, 1)
+	VADC_CHAN_VOLT(P_MUX16_1_3, 1)
+
+	VADC_CHAN_VOLT(LR_MUX1_BAT_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_XO_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX4_AMUX_THM1, 0)
+	VADC_CHAN_VOLT(LR_MUX5_AMUX_THM2, 0)
+	VADC_CHAN_VOLT(LR_MUX6_AMUX_THM3, 0)
+	VADC_CHAN_VOLT(LR_MUX7_HW_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX8_AMUX_THM4, 0)
+	VADC_CHAN_VOLT(LR_MUX9_AMUX_THM5, 0)
+	VADC_CHAN_VOLT(LR_MUX10_USB_ID, 0)
+	VADC_CHAN_VOLT(AMUX_PU1, 0)
+	VADC_CHAN_VOLT(AMUX_PU2, 0)
+	VADC_CHAN_VOLT(LR_MUX3_BUF_XO_THERM, 0)
+
+	VADC_CHAN_VOLT(LR_MUX1_PU1_BAT_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX2_PU1_BAT_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_PU1_XO_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX4_PU1_AMUX_THM1, 0)
+	VADC_CHAN_VOLT(LR_MUX5_PU1_AMUX_THM2, 0)
+	VADC_CHAN_VOLT(LR_MUX6_PU1_AMUX_THM3, 0)
+	VADC_CHAN_VOLT(LR_MUX7_PU1_AMUX_HW_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX8_PU1_AMUX_THM4, 0)
+	VADC_CHAN_VOLT(LR_MUX9_PU1_AMUX_THM5, 0)
+	VADC_CHAN_VOLT(LR_MUX10_PU1_AMUX_USB_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_XO_THERM, 0)
+
+	VADC_CHAN_VOLT(LR_MUX1_PU2_BAT_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX2_PU2_BAT_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_PU2_XO_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX4_PU2_AMUX_THM1, 0)
+	VADC_CHAN_VOLT(LR_MUX5_PU2_AMUX_THM2, 0)
+	VADC_CHAN_VOLT(LR_MUX6_PU2_AMUX_THM3, 0)
+	VADC_CHAN_VOLT(LR_MUX7_PU2_AMUX_HW_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX8_PU2_AMUX_THM4, 0)
+	VADC_CHAN_VOLT(LR_MUX9_PU2_AMUX_THM5, 0)
+	VADC_CHAN_VOLT(LR_MUX10_PU2_AMUX_USB_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_BUF_PU2_XO_THERM, 0)
+
+	VADC_CHAN_VOLT(LR_MUX1_PU1_PU2_BAT_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX2_PU1_PU2_BAT_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_PU1_PU2_XO_THERM, 0)
+	VADC_CHAN_VOLT(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
+	VADC_CHAN_VOLT(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
+	VADC_CHAN_VOLT(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
+	VADC_CHAN_VOLT(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
+	VADC_CHAN_VOLT(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
+	VADC_CHAN_VOLT(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
+	VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
+};
+
+static int vadc_get_dt_channel_data(struct device *dev,
+				    struct vadc_channel_prop *prop,
+				    struct device_node *node)
+{
+	const char *name = node->name;
+	u32 chan, value, varr[2];
+	int ret;
+
+	ret = of_property_read_u32(node, "reg", &chan);
+	if (ret) {
+		dev_err(dev, "invalid channel number %s\n", name);
+		return ret;
+	}
+
+	if (chan > VADC_CHAN_MAX || chan < VADC_CHAN_MIN) {
+		dev_err(dev, "%s invalid channel number %d\n", name, chan);
+		return -EINVAL;
+	}
+
+	/* the channel has DT description */
+	prop->channel = chan;
+
+	ret = of_property_read_u32(node, "qcom,decimation", &value);
+	if (!ret) {
+		ret = vadc_decimation_from_dt(value);
+		if (ret < 0) {
+			dev_err(dev, "%02x invalid decimation %d\n",
+				chan, value);
+			return ret;
+		}
+		prop->decimation = ret;
+	} else {
+		prop->decimation = VADC_DEF_DECIMATION;
+	}
+
+	ret = of_property_read_u32_array(node, "qcom,pre-scaling", varr, 2);
+	if (!ret) {
+		ret = vadc_prescaling_from_dt(varr[0], varr[1]);
+		if (ret < 0) {
+			dev_err(dev, "%02x invalid pre-scaling <%d %d>\n",
+				chan, varr[0], varr[1]);
+			return ret;
+		}
+		prop->prescale = ret;
+	} else {
+		prop->prescale = vadc_chans[prop->channel].prescale_index;
+	}
+
+	ret = of_property_read_u32(node, "qcom,hw-settle-time", &value);
+	if (!ret) {
+		ret = vadc_hw_settle_time_from_dt(value);
+		if (ret < 0) {
+			dev_err(dev, "%02x invalid hw-settle-time %d us\n",
+				chan, value);
+			return ret;
+		}
+		prop->hw_settle_time = ret;
+	} else {
+		prop->hw_settle_time = VADC_DEF_HW_SETTLE_TIME;
+	}
+
+	ret = of_property_read_u32(node, "qcom,avg-samples", &value);
+	if (!ret) {
+		ret = vadc_avg_samples_from_dt(value);
+		if (ret < 0) {
+			dev_err(dev, "%02x invalid avg-samples %d\n",
+				chan, value);
+			return ret;
+		}
+		prop->avg_samples = ret;
+	} else {
+		prop->avg_samples = VADC_DEF_AVG_SAMPLES;
+	}
+
+	if (of_property_read_bool(node, "qcom,ratiometric"))
+		prop->calibration = VADC_CALIB_RATIOMETRIC;
+	else
+		prop->calibration = VADC_CALIB_ABSOLUTE;
+
+	dev_dbg(dev, "%02x name %s\n", chan, name);
+
+	return 0;
+}
+
+static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)
+{
+	const struct vadc_channels *vadc_chan;
+	struct iio_chan_spec *iio_chan;
+	struct vadc_channel_prop prop;
+	struct device_node *child;
+	unsigned int index = 0;
+	int ret;
+
+	vadc->nchannels = of_get_available_child_count(node);
+	if (!vadc->nchannels)
+		return -EINVAL;
+
+	vadc->iio_chans = devm_kcalloc(vadc->dev, vadc->nchannels,
+				       sizeof(*vadc->iio_chans), GFP_KERNEL);
+	if (!vadc->iio_chans)
+		return -ENOMEM;
+
+	vadc->chan_props = devm_kcalloc(vadc->dev, vadc->nchannels,
+					sizeof(*vadc->chan_props), GFP_KERNEL);
+	if (!vadc->chan_props)
+		return -ENOMEM;
+
+	iio_chan = vadc->iio_chans;
+
+	for_each_available_child_of_node(node, child) {
+		ret = vadc_get_dt_channel_data(vadc->dev, &prop, child);
+		if (ret)
+			return ret;
+
+		vadc->chan_props[index] = prop;
+
+		vadc_chan = &vadc_chans[prop.channel];
+
+		iio_chan->channel = prop.channel;
+		iio_chan->datasheet_name = vadc_chan->datasheet_name;
+		iio_chan->info_mask_separate = vadc_chan->info_mask;
+		iio_chan->type = vadc_chan->type;
+		iio_chan->indexed = 1;
+		iio_chan->address = index++;
+
+		iio_chan++;
+	}
+
+	/* These channels are mandatory, they are used as reference points */
+	if (!vadc_get_channel(vadc, VADC_REF_1250MV)) {
+		dev_err(vadc->dev, "Please define 1.25V channel\n");
+		return -ENODEV;
+	}
+
+	if (!vadc_get_channel(vadc, VADC_REF_625MV)) {
+		dev_err(vadc->dev, "Please define 0.625V channel\n");
+		return -ENODEV;
+	}
+
+	if (!vadc_get_channel(vadc, VADC_VDD_VADC)) {
+		dev_err(vadc->dev, "Please define VDD channel\n");
+		return -ENODEV;
+	}
+
+	if (!vadc_get_channel(vadc, VADC_GND_REF)) {
+		dev_err(vadc->dev, "Please define GND channel\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static irqreturn_t vadc_isr(int irq, void *dev_id)
+{
+	struct vadc_priv *vadc = dev_id;
+
+	complete(&vadc->complete);
+
+	return IRQ_HANDLED;
+}
+
+static int vadc_check_revision(struct vadc_priv *vadc)
+{
+	u8 val;
+	int ret;
+
+	ret = vadc_read(vadc, VADC_PERPH_TYPE, &val);
+	if (ret)
+		return ret;
+
+	if (val < VADC_PERPH_TYPE_ADC) {
+		dev_err(vadc->dev, "%d is not ADC\n", val);
+		return -ENODEV;
+	}
+
+	ret = vadc_read(vadc, VADC_PERPH_SUBTYPE, &val);
+	if (ret)
+		return ret;
+
+	if (val < VADC_PERPH_SUBTYPE_VADC) {
+		dev_err(vadc->dev, "%d is not VADC\n", val);
+		return -ENODEV;
+	}
+
+	ret = vadc_read(vadc, VADC_REVISION2, &val);
+	if (ret)
+		return ret;
+
+	if (val < VADC_REVISION2_SUPPORTED_VADC) {
+		dev_err(vadc->dev, "revision %d not supported\n", val);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int vadc_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	struct iio_dev *indio_dev;
+	struct vadc_priv *vadc;
+	struct regmap *regmap;
+	int ret, irq_eoc;
+	u32 reg;
+
+	regmap = dev_get_regmap(dev->parent, NULL);
+	if (!regmap)
+		return -ENODEV;
+
+	ret = of_property_read_u32(node, "reg", &reg);
+	if (ret < 0)
+		return ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*vadc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	vadc = iio_priv(indio_dev);
+	vadc->regmap = regmap;
+	vadc->dev = dev;
+	vadc->base = reg;
+	vadc->are_ref_measured = false;
+	init_completion(&vadc->complete);
+	mutex_init(&vadc->lock);
+
+	ret = vadc_check_revision(vadc);
+	if (ret)
+		return ret;
+
+	ret = vadc_get_dt_data(vadc, node);
+	if (ret)
+		return ret;
+
+	irq_eoc = platform_get_irq(pdev, 0);
+	if (irq_eoc < 0) {
+		if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
+			return irq_eoc;
+		vadc->poll_eoc = true;
+	} else {
+		ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
+				       "spmi-vadc", vadc);
+		if (ret)
+			return ret;
+	}
+
+	ret = vadc_reset(vadc);
+	if (ret) {
+		dev_err(dev, "reset failed\n");
+		return ret;
+	}
+
+	ret = vadc_measure_ref_points(vadc);
+	if (ret)
+		return ret;
+
+	indio_dev->dev.parent = dev;
+	indio_dev->dev.of_node = node;
+	indio_dev->name = pdev->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &vadc_info;
+	indio_dev->channels = vadc->iio_chans;
+	indio_dev->num_channels = vadc->nchannels;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id vadc_match_table[] = {
+	{ .compatible = "qcom,spmi-vadc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, vadc_match_table);
+
+static struct platform_driver vadc_driver = {
+	.driver = {
+		   .name = "qcom-spmi-vadc",
+		   .of_match_table = vadc_match_table,
+	},
+	.probe = vadc_probe,
+};
+module_platform_driver(vadc_driver);
+
+MODULE_ALIAS("platform:qcom-spmi-vadc");
+MODULE_DESCRIPTION("Qualcomm SPMI PMIC voltage ADC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Stanimir Varbanov <svarbanov@mm-sol.com>");
+MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");
--
1.9.1

Re: [PATCH v5 0/2] Initial support for voltage ADC

[Ivan T. Ivanov]

On Tue, 2015-01-20 at 12:15 +0200, Ivan T. Ivanov wrote:
> This type of volatage ADC could be found in Qualcomm's SPMI PMIC's.
> I'm sorry that it took me so long to send the updated version.
> 
> Changes since v4.
> - Addressed review comments from Hartmut Knaack and Jonathan Cameron:
>   Fixed spelling errors in DT description files.
>   Removed unused structure member.
>   Access to hardware during conversion is protected with mutex.
>   Measuring reference points moved at driver probe time.
> 
> Patches are based on current iio/testing branch.

Hi, 

Are there any comments on these patches?

Regards,
Ivan

> 
> v4 could be found here: https://lkml.org/lkml/2014/11/3/425
> 
> Stanimir Varbanov (2):
>   DT: iio: vadc: document dt binding
>   iio: vadc: Qualcomm SPMI PMIC voltage ADC driver
> 
>  .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt |  129 +++
>  drivers/iio/adc/Kconfig                            |   14 +
>  drivers/iio/adc/Makefile                           |    1 +
>  drivers/iio/adc/qcom-spmi-vadc.c                   | 1016 ++++++++++++++++++++
>  include/dt-bindings/iio/qcom,spmi-vadc.h           |  119 +++
>  5 files changed, 1279 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
>  create mode 100644 drivers/iio/adc/qcom-spmi-vadc.c
>  create mode 100644 include/dt-bindings/iio/qcom,spmi-vadc.h
> 
> --
> 1.9.1
> 
> 

Re: [PATCH v5 1/2] DT: iio: vadc: document dt binding

[Jonathan Cameron]

On 20/01/15 10:15, Ivan T. Ivanov wrote:
> From: Stanimir Varbanov <svarbanov@mm-sol.com>
> 
> 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>
Given the only changes since the previous version (back in
November are trivial typo corrections) I'm deeming this
to have met the 3 weeks waiting for any DT responses and
taking it through IIO.

Applied to the togreg branch of iio.git - initially pushed out
as testing.

Jonathan
> ---
>  .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt | 129 +++++++++++++++++++++
>  include/dt-bindings/iio/qcom,spmi-vadc.h           | 119 +++++++++++++++++++
>  2 files changed, 248 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
>  create mode 100644 include/dt-bindings/iio/qcom,spmi-vadc.h
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
> new file mode 100644
> index 0000000..0fb4613
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
> @@ -0,0 +1,129 @@
> +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";
> +	};
> diff --git a/include/dt-bindings/iio/qcom,spmi-vadc.h b/include/dt-bindings/iio/qcom,spmi-vadc.h
> new file mode 100644
> index 0000000..42121fa
> --- /dev/null
> +++ b/include/dt-bindings/iio/qcom,spmi-vadc.h
> @@ -0,0 +1,119 @@
> +/*
> + * 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 */
> --
> 1.9.1
> 

Re: [PATCH v5 2/2] iio: vadc: Qualcomm SPMI PMIC voltage ADC driver

[Jonathan Cameron]

On 20/01/15 10:15, Ivan T. Ivanov wrote:
> From: Stanimir Varbanov <svarbanov@mm-sol.com>
> 
> The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
> 15bits resolution and register space inside PMIC accessible across
> SPMI bus.
> 
> The vadc driver registers itself through IIO interface.
> 
> Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
> Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
One minor comment inline.  Looks good to me.
Applied to the togreg branch of iio.git - initially pushed out as testing.

Glad to have this one out of the pending list ;)
> ---
>  drivers/iio/adc/Kconfig          |   14 +
>  drivers/iio/adc/Makefile         |    1 +
>  drivers/iio/adc/qcom-spmi-vadc.c | 1016 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1031 insertions(+)
>  create mode 100644 drivers/iio/adc/qcom-spmi-vadc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index d0924f3..792e2b8 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -220,6 +220,20 @@ config QCOM_SPMI_IADC
>  	  To compile this driver as a module, choose M here: the module will
>  	  be called qcom-spmi-iadc.
> 
> +config QCOM_SPMI_VADC
> +	tristate "Qualcomm SPMI PMIC voltage ADC"
> +	depends on SPMI
> +	select REGMAP_SPMI
> +	help
> +	  This is the IIO Voltage ADC driver for Qualcomm QPNP VADC Chip.
> +
> +	  The driver supports multiple channels read. The VADC is a 15-bit
> +	  sigma-delta ADC. Some of the channels are internally used for
> +	  calibration.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called qcom-spmi-vadc.
> +
>  config ROCKCHIP_SARADC
>  	tristate "Rockchip SARADC driver"
>  	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index c06718b..285b0a0 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_MCP3422) += mcp3422.o
>  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
>  obj-$(CONFIG_NAU7802) += nau7802.o
>  obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
> +obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
>  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
>  obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>  obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
> diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
> new file mode 100644
> index 0000000..3211729
> --- /dev/null
> +++ b/drivers/iio/adc/qcom-spmi-vadc.c
> @@ -0,0 +1,1016 @@
> +/*
> + * 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.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +
> +#include <dt-bindings/iio/qcom,spmi-vadc.h>
> +
> +/* VADC register and bit definitions */
> +#define VADC_REVISION2				0x1
> +#define VADC_REVISION2_SUPPORTED_VADC		1
> +
> +#define VADC_PERPH_TYPE				0x4
> +#define VADC_PERPH_TYPE_ADC			8
> +
> +#define VADC_PERPH_SUBTYPE			0x5
> +#define VADC_PERPH_SUBTYPE_VADC			1
> +
> +#define VADC_STATUS1				0x8
> +#define VADC_STATUS1_OP_MODE			4
> +#define VADC_STATUS1_REQ_STS			BIT(1)
> +#define VADC_STATUS1_EOC			BIT(0)
> +#define VADC_STATUS1_REQ_STS_EOC_MASK		0x3
> +
> +#define VADC_MODE_CTL				0x40
> +#define VADC_OP_MODE_SHIFT			3
> +#define VADC_OP_MODE_NORMAL			0
> +#define VADC_AMUX_TRIM_EN			BIT(1)
> +#define VADC_ADC_TRIM_EN			BIT(0)
> +
> +#define VADC_EN_CTL1				0x46
> +#define VADC_EN_CTL1_SET			BIT(7)
> +
> +#define VADC_ADC_CH_SEL_CTL			0x48
> +
> +#define VADC_ADC_DIG_PARAM			0x50
> +#define VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT	2
> +
> +#define VADC_HW_SETTLE_DELAY			0x51
> +
> +#define VADC_CONV_REQ				0x52
> +#define VADC_CONV_REQ_SET			BIT(7)
> +
> +#define VADC_FAST_AVG_CTL			0x5a
> +#define VADC_FAST_AVG_EN			0x5b
> +#define VADC_FAST_AVG_EN_SET			BIT(7)
> +
> +#define VADC_ACCESS				0xd0
> +#define VADC_ACCESS_DATA			0xa5
> +
> +#define VADC_PERH_RESET_CTL3			0xda
> +#define VADC_FOLLOW_WARM_RB			BIT(2)
> +
> +#define VADC_DATA				0x60	/* 16 bits */
> +
> +#define VADC_CONV_TIME_MIN_US			2000
> +#define VADC_CONV_TIME_MAX_US			2100
> +
> +/* Min ADC code represents 0V */
> +#define VADC_MIN_ADC_CODE			0x6000
> +/* Max ADC code represents full-scale range of 1.8V */
> +#define VADC_MAX_ADC_CODE			0xa800
> +
> +#define VADC_ABSOLUTE_RANGE_UV			625000
> +#define VADC_RATIOMETRIC_RANGE_UV		1800000
> +
> +#define VADC_DEF_PRESCALING			0 /* 1:1 */
> +#define VADC_DEF_DECIMATION			0 /* 512 */
> +#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */
> +#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */
> +#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE
> +
> +#define VADC_DECIMATION_MIN			512
> +#define VADC_DECIMATION_MAX			4096
> +
> +#define VADC_HW_SETTLE_DELAY_MAX		10000
> +#define VADC_AVG_SAMPLES_MAX			512
> +
> +#define KELVINMIL_CELSIUSMIL			273150
> +
> +#define VADC_CHAN_MIN			VADC_USBIN
> +#define VADC_CHAN_MAX			VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
> +
> +/*
> + * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
> + * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
> + * calibration.
> + */
> +enum vadc_calibration {
> +	VADC_CALIB_ABSOLUTE = 0,
> +	VADC_CALIB_RATIOMETRIC
> +};
> +
> +/**
> + * struct vadc_linear_graph - Represent ADC characteristics.
> + * @dy: numerator slope to calculate the gain.
> + * @dx: denominator slope to calculate the gain.
> + * @gnd: A/D word of the ground reference used for the channel.
> + *
> + * Each ADC device has different offset and gain parameters which are
> + * computed to calibrate the device.
> + */
> +struct vadc_linear_graph {
> +	s32 dy;
> +	s32 dx;
> +	s32 gnd;
> +};
> +
> +/**
> + * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
> + * @num: the inverse numerator of the gain applied to the input channel.
> + * @den: the inverse denominator of the gain applied to the input channel.
> + */
> +struct vadc_prescale_ratio {
> +	u32 num;
> +	u32 den;
> +};
> +
> +/**
> + * struct vadc_channel_prop - VADC channel property.
> + * @channel: channel number, refer to the channel list.
> + * @calibration: calibration type.
> + * @decimation: sampling rate supported for the channel.
> + * @prescale: channel scaling performed on the input signal.
> + * @hw_settle_time: the time between AMUX being configured and the
> + *	start of conversion.
> + * @avg_samples: ability to provide single result from the ADC
> + *	that is an average of multiple measurements.
> + */
> +struct vadc_channel_prop {
> +	unsigned int channel;
> +	enum vadc_calibration calibration;
> +	unsigned int decimation;
> +	unsigned int prescale;
> +	unsigned int hw_settle_time;
> +	unsigned int avg_samples;
> +};
> +
> +/**
> + * struct vadc_priv - VADC private structure.
> + * @regmap: pointer to struct regmap.
> + * @dev: pointer to struct device.
> + * @base: base address for the ADC peripheral.
> + * @nchannels: number of VADC channels.
> + * @chan_props: array of VADC channel properties.
> + * @iio_chans: array of IIO channels specification.
> + * @are_ref_measured: are reference points measured.
> + * @poll_eoc: use polling instead of interrupt.
> + * @complete: VADC result notification after interrupt is received.
> + * @graph: store parameters for calibration.
> + * @lock: ADC lock for access to the peripheral.
> + */
> +struct vadc_priv {
> +	struct regmap		 *regmap;
> +	struct device		 *dev;
> +	u16			 base;
> +	unsigned int		 nchannels;
> +	struct vadc_channel_prop *chan_props;
> +	struct iio_chan_spec	 *iio_chans;
> +	bool			 are_ref_measured;
> +	bool			 poll_eoc;
> +	struct completion	 complete;
> +	struct vadc_linear_graph graph[2];
> +	struct mutex		 lock;
> +};
> +
> +static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
> +	{.num =  1, .den =  1},
> +	{.num =  1, .den =  3},
> +	{.num =  1, .den =  4},
> +	{.num =  1, .den =  6},
> +	{.num =  1, .den = 20},
> +	{.num =  1, .den =  8},
> +	{.num = 10, .den = 81},
> +	{.num =  1, .den = 10}
> +};
> +
> +static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
> +{
> +	return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
> +}
> +
> +static int vadc_write(struct vadc_priv *vadc, u16 offset, u8 data)
> +{
> +	return regmap_write(vadc->regmap, vadc->base + offset, data);
> +}
> +
> +static int vadc_reset(struct vadc_priv *vadc)
> +{
> +	u8 data;
> +	int ret;
> +
> +	ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
> +	if (ret)
> +		return ret;
> +
> +	ret = vadc_read(vadc, VADC_PERH_RESET_CTL3, &data);
> +	if (ret)
> +		return ret;
> +
> +	ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
> +	if (ret)
> +		return ret;
> +
> +	data |= VADC_FOLLOW_WARM_RB;
> +
> +	return vadc_write(vadc, VADC_PERH_RESET_CTL3, data);
> +}
> +
> +static int vadc_set_state(struct vadc_priv *vadc, bool state)
> +{
> +	return vadc_write(vadc, VADC_EN_CTL1, state ? VADC_EN_CTL1_SET : 0);
> +}
> +
> +static void vadc_show_status(struct vadc_priv *vadc)
> +{
> +	u8 mode, sta1, chan, dig, en, req;
> +	int ret;
> +
> +	ret = vadc_read(vadc, VADC_MODE_CTL, &mode);
> +	if (ret)
> +		return;
> +
> +	ret = vadc_read(vadc, VADC_ADC_DIG_PARAM, &dig);
> +	if (ret)
> +		return;
> +
> +	ret = vadc_read(vadc, VADC_ADC_CH_SEL_CTL, &chan);
> +	if (ret)
> +		return;
> +
> +	ret = vadc_read(vadc, VADC_CONV_REQ, &req);
> +	if (ret)
> +		return;
> +
> +	ret = vadc_read(vadc, VADC_STATUS1, &sta1);
> +	if (ret)
> +		return;
> +
> +	ret = vadc_read(vadc, VADC_EN_CTL1, &en);
> +	if (ret)
> +		return;
> +
> +	dev_err(vadc->dev,
> +		"mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n",
> +		mode, en, chan, dig, req, sta1);
> +}
> +
> +static int vadc_configure(struct vadc_priv *vadc,
> +			  struct vadc_channel_prop *prop)
> +{
> +	u8 decimation, mode_ctrl;
> +	int ret;
> +
> +	/* Mode selection */
> +	mode_ctrl = (VADC_OP_MODE_NORMAL << VADC_OP_MODE_SHIFT) |
> +		     VADC_ADC_TRIM_EN | VADC_AMUX_TRIM_EN;
> +	ret = vadc_write(vadc, VADC_MODE_CTL, mode_ctrl);
> +	if (ret)
> +		return ret;
> +
> +	/* Channel selection */
> +	ret = vadc_write(vadc, VADC_ADC_CH_SEL_CTL, prop->channel);
> +	if (ret)
> +		return ret;
> +
> +	/* Digital parameter setup */
> +	decimation = prop->decimation << VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT;
> +	ret = vadc_write(vadc, VADC_ADC_DIG_PARAM, decimation);
> +	if (ret)
> +		return ret;
> +
> +	/* HW settle time delay */
> +	ret = vadc_write(vadc, VADC_HW_SETTLE_DELAY, prop->hw_settle_time);
> +	if (ret)
> +		return ret;
> +
> +	ret = vadc_write(vadc, VADC_FAST_AVG_CTL, prop->avg_samples);
> +	if (ret)
> +		return ret;
> +
> +	if (prop->avg_samples)
> +		ret = vadc_write(vadc, VADC_FAST_AVG_EN, VADC_FAST_AVG_EN_SET);
> +	else
> +		ret = vadc_write(vadc, VADC_FAST_AVG_EN, 0);
> +
> +	return ret;
> +}
> +
> +static int vadc_poll_wait_eoc(struct vadc_priv *vadc, unsigned int interval_us)
> +{
> +	unsigned int count, retry;
> +	u8 sta1;
> +	int ret;
> +
> +	retry = interval_us / VADC_CONV_TIME_MIN_US;
> +
> +	for (count = 0; count < retry; count++) {
> +		ret = vadc_read(vadc, VADC_STATUS1, &sta1);
> +		if (ret)
> +			return ret;
> +
> +		sta1 &= VADC_STATUS1_REQ_STS_EOC_MASK;
> +		if (sta1 == VADC_STATUS1_EOC)
> +			return 0;
> +
> +		usleep_range(VADC_CONV_TIME_MIN_US, VADC_CONV_TIME_MAX_US);
> +	}
> +
> +	vadc_show_status(vadc);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static int vadc_read_result(struct vadc_priv *vadc, u16 *data)
> +{
> +	int ret;
> +
> +	ret = regmap_bulk_read(vadc->regmap, vadc->base + VADC_DATA, data, 2);
> +	if (ret)
> +		return ret;
> +
> +	*data = clamp_t(u16, *data, VADC_MIN_ADC_CODE, VADC_MAX_ADC_CODE);
> +
> +	return 0;
> +}
> +
> +static struct vadc_channel_prop *vadc_get_channel(struct vadc_priv *vadc,
> +						  unsigned int num)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < vadc->nchannels; i++)
> +		if (vadc->chan_props[i].channel == num)
> +			return &vadc->chan_props[i];
> +
> +	dev_dbg(vadc->dev, "no such channel %02x\n", num);
> +
> +	return NULL;
> +}
> +
> +static int vadc_do_conversion(struct vadc_priv *vadc,
> +			      struct vadc_channel_prop *prop, u16 *data)
> +{
> +	unsigned int timeout;
> +	int ret;
> +
> +	mutex_lock(&vadc->lock);
> +
> +	ret = vadc_configure(vadc, prop);
> +	if (ret)
> +		goto unlock;
> +
> +	if (!vadc->poll_eoc)
> +		reinit_completion(&vadc->complete);
> +
> +	ret = vadc_set_state(vadc, true);
> +	if (ret)
> +		goto unlock;
> +
> +	ret = vadc_write(vadc, VADC_CONV_REQ, VADC_CONV_REQ_SET);
> +	if (ret)
> +		goto err_disable;
> +
> +	timeout = BIT(prop->avg_samples) * VADC_CONV_TIME_MIN_US * 2;
> +
> +	if (vadc->poll_eoc) {
> +		ret = vadc_poll_wait_eoc(vadc, timeout);
> +	} else {
> +		ret = wait_for_completion_timeout(&vadc->complete, timeout);
> +		if (!ret) {
> +			ret = -ETIMEDOUT;
> +			goto err_disable;
> +		}
> +
> +		/* Double check conversion status */
> +		ret = vadc_poll_wait_eoc(vadc, VADC_CONV_TIME_MIN_US);
> +		if (ret)
> +			goto err_disable;
> +	}
> +
> +	ret = vadc_read_result(vadc, data);
> +
> +err_disable:
> +	vadc_set_state(vadc, false);
> +	if (ret)
> +		dev_err(vadc->dev, "conversion failed\n");
> +unlock:
> +	mutex_unlock(&vadc->lock);
> +	return ret;
> +}
> +
> +static int vadc_measure_ref_points(struct vadc_priv *vadc)
> +{
> +	struct vadc_channel_prop *prop;
> +	u16 read_1, read_2;
> +	int ret;
> +
> +	vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE_UV;
> +	vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
> +
> +	prop = vadc_get_channel(vadc, VADC_REF_1250MV);
> +	ret = vadc_do_conversion(vadc, prop, &read_1);
> +	if (ret)
> +		goto err;
> +
> +	/* Try with buffered 625mV channel first */
> +	prop = vadc_get_channel(vadc, VADC_SPARE1);
> +	if (!prop)
> +		prop = vadc_get_channel(vadc, VADC_REF_625MV);
> +
> +	ret = vadc_do_conversion(vadc, prop, &read_2);
> +	if (ret)
> +		goto err;
> +
> +	if (read_1 == read_2) {
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	vadc->graph[VADC_CALIB_ABSOLUTE].dy = read_1 - read_2;
> +	vadc->graph[VADC_CALIB_ABSOLUTE].gnd = read_2;
> +
> +	/* Ratiometric calibration */
> +	prop = vadc_get_channel(vadc, VADC_VDD_VADC);
> +	ret = vadc_do_conversion(vadc, prop, &read_1);
> +	if (ret)
> +		goto err;
> +
> +	prop = vadc_get_channel(vadc, VADC_GND_REF);
> +	ret = vadc_do_conversion(vadc, prop, &read_2);
> +	if (ret)
> +		goto err;
> +
> +	if (read_1 == read_2) {
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	vadc->graph[VADC_CALIB_RATIOMETRIC].dy = read_1 - read_2;
> +	vadc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_2;
> +err:
> +	if (ret)
> +		dev_err(vadc->dev, "measure reference points failed\n");
> +
> +	return ret;
> +}
> +
> +static s32 vadc_calibrate(struct vadc_priv *vadc,
> +			  const struct vadc_channel_prop *prop, u16 adc_code)
> +{
> +	const struct vadc_prescale_ratio *prescale;
> +	s32 voltage;
> +
> +	voltage = adc_code - vadc->graph[prop->calibration].gnd;
> +	voltage *= vadc->graph[prop->calibration].dx;
> +	voltage = voltage / vadc->graph[prop->calibration].dy;
> +
> +	if (prop->calibration == VADC_CALIB_ABSOLUTE)
> +		voltage += vadc->graph[prop->calibration].dx;
> +
> +	if (voltage < 0)
> +		voltage = 0;
> +
> +	prescale = &vadc_prescale_ratios[prop->prescale];
> +
> +	voltage = voltage * prescale->den;
> +
> +	return voltage / prescale->num;
> +}
> +
> +static int vadc_decimation_from_dt(u32 value)
> +{
> +	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
> +	    value > VADC_DECIMATION_MAX)
> +		return -EINVAL;
> +
> +	return __ffs64(value / VADC_DECIMATION_MIN);
> +}
> +
> +static int vadc_prescaling_from_dt(u32 num, u32 den)
> +{
> +	unsigned int pre;
> +
> +	for (pre = 0; pre < ARRAY_SIZE(vadc_prescale_ratios); pre++)
> +		if (vadc_prescale_ratios[pre].num == num &&
> +		    vadc_prescale_ratios[pre].den == den)
> +			break;
> +
> +	if (pre == ARRAY_SIZE(vadc_prescale_ratios))
> +		return -EINVAL;
> +
> +	return pre;
> +}
> +
> +static int vadc_hw_settle_time_from_dt(u32 value)
> +{
> +	if ((value <= 1000 && value % 100) || (value > 1000 && value % 2000))
> +		return -EINVAL;
> +
> +	if (value <= 1000)
> +		value /= 100;
> +	else
> +		value = value / 2000 + 10;
> +
> +	return value;
> +}
> +
> +static int vadc_avg_samples_from_dt(u32 value)
> +{
> +	if (!is_power_of_2(value) || value > VADC_AVG_SAMPLES_MAX)
> +		return -EINVAL;
> +
> +	return __ffs64(value);
> +}
> +
> +static int vadc_read_raw(struct iio_dev *indio_dev,
> +			 struct iio_chan_spec const *chan, int *val, int *val2,
> +			 long mask)
> +{
> +	struct vadc_priv *vadc = iio_priv(indio_dev);
> +	struct vadc_channel_prop *prop;
> +	u16 adc_code;
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_PROCESSED:
> +		prop = &vadc->chan_props[chan->address];
> +		ret = vadc_do_conversion(vadc, prop, &adc_code);
> +		if (ret)
> +			break;
> +
> +		*val = vadc_calibrate(vadc, prop, adc_code);
> +
> +		/* 2mV/K, return milli Celsius */
> +		*val /= 2;
> +		*val -= KELVINMIL_CELSIUSMIL;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_RAW:
> +		prop = &vadc->chan_props[chan->address];
> +		ret = vadc_do_conversion(vadc, prop, &adc_code);
> +		if (ret)
> +			break;
> +
> +		*val = vadc_calibrate(vadc, prop, adc_code);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 0;
> +		*val2 = 1000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int vadc_of_xlate(struct iio_dev *indio_dev,
> +			 const struct of_phandle_args *iiospec)
> +{
> +	struct vadc_priv *vadc = iio_priv(indio_dev);
> +	unsigned int i;
> +
> +	for (i = 0; i < vadc->nchannels; i++)
> +		if (vadc->iio_chans[i].channel == iiospec->args[0])
> +			return i;
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info vadc_info = {
> +	.read_raw = vadc_read_raw,
> +	.of_xlate = vadc_of_xlate,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +struct vadc_channels {
> +	const char *datasheet_name;
> +	unsigned int prescale_index;
> +	enum iio_chan_type type;
> +	long info_mask;
> +};
> +
> +#define VADC_CHAN(_dname, _type, _mask, _pre)				\
> +	[VADC_##_dname] = {						\
> +		.datasheet_name = __stringify(_dname),			\
> +		.prescale_index = _pre,					\
> +		.type = _type,						\
> +		.info_mask = _mask					\
> +	},								\
> +
> +#define VADC_CHAN_TEMP(_dname, _pre)					\
> +	VADC_CHAN(_dname, IIO_TEMP, BIT(IIO_CHAN_INFO_PROCESSED), _pre)	\
> +
> +#define VADC_CHAN_VOLT(_dname, _pre)					\
> +	VADC_CHAN(_dname, IIO_VOLTAGE,					\
> +		  BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),	\
> +		  _pre)							\
> +
> +/*
> + * The array represents all possible ADC channels found in the supported PMICs.
> + * Every index in the array is equal to the channel number per datasheet. The
> + * gaps in the array should be treated as reserved channels.
> + */
> +static const struct vadc_channels vadc_chans[] = {
> +	VADC_CHAN_VOLT(USBIN, 4)
> +	VADC_CHAN_VOLT(DCIN, 4)
> +	VADC_CHAN_VOLT(VCHG_SNS, 3)
> +	VADC_CHAN_VOLT(SPARE1_03, 1)
> +	VADC_CHAN_VOLT(USB_ID_MV, 1)
> +	VADC_CHAN_VOLT(VCOIN, 1)
> +	VADC_CHAN_VOLT(VBAT_SNS, 1)
> +	VADC_CHAN_VOLT(VSYS, 1)
> +	VADC_CHAN_TEMP(DIE_TEMP, 0)
> +	VADC_CHAN_VOLT(REF_625MV, 0)
> +	VADC_CHAN_VOLT(REF_1250MV, 0)
> +	VADC_CHAN_VOLT(CHG_TEMP, 0)
> +	VADC_CHAN_VOLT(SPARE1, 0)
> +	VADC_CHAN_VOLT(SPARE2, 0)
> +	VADC_CHAN_VOLT(GND_REF, 0)
> +	VADC_CHAN_VOLT(VDD_VADC, 0)
> +
> +	VADC_CHAN_VOLT(P_MUX1_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX2_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX3_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX4_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX5_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX6_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX7_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX8_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX9_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX10_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX11_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX12_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX13_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX14_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX15_1_1, 0)
> +	VADC_CHAN_VOLT(P_MUX16_1_1, 0)
> +
> +	VADC_CHAN_VOLT(P_MUX1_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX2_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX3_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX4_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX5_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX6_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX7_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX8_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX9_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX10_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX11_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX12_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX13_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX14_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX15_1_3, 1)
> +	VADC_CHAN_VOLT(P_MUX16_1_3, 1)
> +
> +	VADC_CHAN_VOLT(LR_MUX1_BAT_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_XO_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX4_AMUX_THM1, 0)
> +	VADC_CHAN_VOLT(LR_MUX5_AMUX_THM2, 0)
> +	VADC_CHAN_VOLT(LR_MUX6_AMUX_THM3, 0)
> +	VADC_CHAN_VOLT(LR_MUX7_HW_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX8_AMUX_THM4, 0)
> +	VADC_CHAN_VOLT(LR_MUX9_AMUX_THM5, 0)
> +	VADC_CHAN_VOLT(LR_MUX10_USB_ID, 0)
> +	VADC_CHAN_VOLT(AMUX_PU1, 0)
> +	VADC_CHAN_VOLT(AMUX_PU2, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_BUF_XO_THERM, 0)
> +
> +	VADC_CHAN_VOLT(LR_MUX1_PU1_BAT_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX2_PU1_BAT_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_PU1_XO_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX4_PU1_AMUX_THM1, 0)
> +	VADC_CHAN_VOLT(LR_MUX5_PU1_AMUX_THM2, 0)
> +	VADC_CHAN_VOLT(LR_MUX6_PU1_AMUX_THM3, 0)
> +	VADC_CHAN_VOLT(LR_MUX7_PU1_AMUX_HW_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX8_PU1_AMUX_THM4, 0)
> +	VADC_CHAN_VOLT(LR_MUX9_PU1_AMUX_THM5, 0)
> +	VADC_CHAN_VOLT(LR_MUX10_PU1_AMUX_USB_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_XO_THERM, 0)
> +
> +	VADC_CHAN_VOLT(LR_MUX1_PU2_BAT_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX2_PU2_BAT_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_PU2_XO_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX4_PU2_AMUX_THM1, 0)
> +	VADC_CHAN_VOLT(LR_MUX5_PU2_AMUX_THM2, 0)
> +	VADC_CHAN_VOLT(LR_MUX6_PU2_AMUX_THM3, 0)
> +	VADC_CHAN_VOLT(LR_MUX7_PU2_AMUX_HW_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX8_PU2_AMUX_THM4, 0)
> +	VADC_CHAN_VOLT(LR_MUX9_PU2_AMUX_THM5, 0)
> +	VADC_CHAN_VOLT(LR_MUX10_PU2_AMUX_USB_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_BUF_PU2_XO_THERM, 0)
> +
> +	VADC_CHAN_VOLT(LR_MUX1_PU1_PU2_BAT_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX2_PU1_PU2_BAT_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_PU1_PU2_XO_THERM, 0)
> +	VADC_CHAN_VOLT(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
> +	VADC_CHAN_VOLT(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
> +	VADC_CHAN_VOLT(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
> +	VADC_CHAN_VOLT(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
> +	VADC_CHAN_VOLT(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
> +	VADC_CHAN_VOLT(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
> +	VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
> +};
> +
> +static int vadc_get_dt_channel_data(struct device *dev,
> +				    struct vadc_channel_prop *prop,
> +				    struct device_node *node)
> +{
> +	const char *name = node->name;
> +	u32 chan, value, varr[2];
> +	int ret;
> +
> +	ret = of_property_read_u32(node, "reg", &chan);
> +	if (ret) {
> +		dev_err(dev, "invalid channel number %s\n", name);
> +		return ret;
> +	}
> +
> +	if (chan > VADC_CHAN_MAX || chan < VADC_CHAN_MIN) {
> +		dev_err(dev, "%s invalid channel number %d\n", name, chan);
> +		return -EINVAL;
> +	}
> +
> +	/* the channel has DT description */
> +	prop->channel = chan;
> +
> +	ret = of_property_read_u32(node, "qcom,decimation", &value);
> +	if (!ret) {
> +		ret = vadc_decimation_from_dt(value);
> +		if (ret < 0) {
> +			dev_err(dev, "%02x invalid decimation %d\n",
> +				chan, value);
> +			return ret;
> +		}
> +		prop->decimation = ret;
> +	} else {
> +		prop->decimation = VADC_DEF_DECIMATION;
> +	}
> +
> +	ret = of_property_read_u32_array(node, "qcom,pre-scaling", varr, 2);
> +	if (!ret) {
> +		ret = vadc_prescaling_from_dt(varr[0], varr[1]);
> +		if (ret < 0) {
> +			dev_err(dev, "%02x invalid pre-scaling <%d %d>\n",
> +				chan, varr[0], varr[1]);
> +			return ret;
> +		}
> +		prop->prescale = ret;
> +	} else {
> +		prop->prescale = vadc_chans[prop->channel].prescale_index;
> +	}
> +
> +	ret = of_property_read_u32(node, "qcom,hw-settle-time", &value);
> +	if (!ret) {
> +		ret = vadc_hw_settle_time_from_dt(value);
> +		if (ret < 0) {
> +			dev_err(dev, "%02x invalid hw-settle-time %d us\n",
> +				chan, value);
> +			return ret;
> +		}
> +		prop->hw_settle_time = ret;
> +	} else {
> +		prop->hw_settle_time = VADC_DEF_HW_SETTLE_TIME;
> +	}
> +
> +	ret = of_property_read_u32(node, "qcom,avg-samples", &value);
> +	if (!ret) {
> +		ret = vadc_avg_samples_from_dt(value);
> +		if (ret < 0) {
> +			dev_err(dev, "%02x invalid avg-samples %d\n",
> +				chan, value);
> +			return ret;
> +		}
> +		prop->avg_samples = ret;
> +	} else {
> +		prop->avg_samples = VADC_DEF_AVG_SAMPLES;
> +	}
> +
> +	if (of_property_read_bool(node, "qcom,ratiometric"))
> +		prop->calibration = VADC_CALIB_RATIOMETRIC;
> +	else
> +		prop->calibration = VADC_CALIB_ABSOLUTE;
> +
> +	dev_dbg(dev, "%02x name %s\n", chan, name);
> +
> +	return 0;
> +}
> +
> +static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)
> +{
> +	const struct vadc_channels *vadc_chan;
> +	struct iio_chan_spec *iio_chan;
> +	struct vadc_channel_prop prop;
> +	struct device_node *child;
> +	unsigned int index = 0;
> +	int ret;
> +
> +	vadc->nchannels = of_get_available_child_count(node);
> +	if (!vadc->nchannels)
> +		return -EINVAL;
> +
> +	vadc->iio_chans = devm_kcalloc(vadc->dev, vadc->nchannels,
> +				       sizeof(*vadc->iio_chans), GFP_KERNEL);
> +	if (!vadc->iio_chans)
> +		return -ENOMEM;
> +
> +	vadc->chan_props = devm_kcalloc(vadc->dev, vadc->nchannels,
> +					sizeof(*vadc->chan_props), GFP_KERNEL);
> +	if (!vadc->chan_props)
> +		return -ENOMEM;
> +
> +	iio_chan = vadc->iio_chans;
> +
> +	for_each_available_child_of_node(node, child) {
> +		ret = vadc_get_dt_channel_data(vadc->dev, &prop, child);
> +		if (ret)
> +			return ret;
> +
> +		vadc->chan_props[index] = prop;
> +
> +		vadc_chan = &vadc_chans[prop.channel];
> +
> +		iio_chan->channel = prop.channel;
> +		iio_chan->datasheet_name = vadc_chan->datasheet_name;
> +		iio_chan->info_mask_separate = vadc_chan->info_mask;
> +		iio_chan->type = vadc_chan->type;
> +		iio_chan->indexed = 1;
> +		iio_chan->address = index++;
> +
> +		iio_chan++;
> +	}
> +
> +	/* These channels are mandatory, they are used as reference points */
> +	if (!vadc_get_channel(vadc, VADC_REF_1250MV)) {
> +		dev_err(vadc->dev, "Please define 1.25V channel\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!vadc_get_channel(vadc, VADC_REF_625MV)) {
> +		dev_err(vadc->dev, "Please define 0.625V channel\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!vadc_get_channel(vadc, VADC_VDD_VADC)) {
> +		dev_err(vadc->dev, "Please define VDD channel\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!vadc_get_channel(vadc, VADC_GND_REF)) {
> +		dev_err(vadc->dev, "Please define GND channel\n");
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t vadc_isr(int irq, void *dev_id)
> +{
> +	struct vadc_priv *vadc = dev_id;
> +
> +	complete(&vadc->complete);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int vadc_check_revision(struct vadc_priv *vadc)
> +{
> +	u8 val;
> +	int ret;
> +
> +	ret = vadc_read(vadc, VADC_PERPH_TYPE, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val < VADC_PERPH_TYPE_ADC) {
> +		dev_err(vadc->dev, "%d is not ADC\n", val);
> +		return -ENODEV;
> +	}
> +
> +	ret = vadc_read(vadc, VADC_PERPH_SUBTYPE, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val < VADC_PERPH_SUBTYPE_VADC) {
> +		dev_err(vadc->dev, "%d is not VADC\n", val);
> +		return -ENODEV;
> +	}
> +
> +	ret = vadc_read(vadc, VADC_REVISION2, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val < VADC_REVISION2_SUPPORTED_VADC) {
> +		dev_err(vadc->dev, "revision %d not supported\n", val);
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vadc_probe(struct platform_device *pdev)
> +{
> +	struct device_node *node = pdev->dev.of_node;
> +	struct device *dev = &pdev->dev;
> +	struct iio_dev *indio_dev;
> +	struct vadc_priv *vadc;
> +	struct regmap *regmap;
> +	int ret, irq_eoc;
> +	u32 reg;
> +
> +	regmap = dev_get_regmap(dev->parent, NULL);
> +	if (!regmap)
> +		return -ENODEV;
> +
> +	ret = of_property_read_u32(node, "reg", &reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*vadc));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	vadc = iio_priv(indio_dev);
> +	vadc->regmap = regmap;
> +	vadc->dev = dev;
> +	vadc->base = reg;
> +	vadc->are_ref_measured = false;
> +	init_completion(&vadc->complete);
> +	mutex_init(&vadc->lock);
> +
> +	ret = vadc_check_revision(vadc);
> +	if (ret)
> +		return ret;
> +
> +	ret = vadc_get_dt_data(vadc, node);
> +	if (ret)
> +		return ret;
> +
> +	irq_eoc = platform_get_irq(pdev, 0);
> +	if (irq_eoc < 0) {
> +		if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
> +			return irq_eoc;
This does feel a little backwards.  I'd normally expect to see those
errors that indicate one is not specified tested against, rather than
trying to guess all the reasons it might fail otherwise....

This way round strikes me as probably more fragile as additional errors
may turn up in that function over time..

> +		vadc->poll_eoc = true;
> +	} else {
> +		ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
> +				       "spmi-vadc", vadc);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = vadc_reset(vadc);
> +	if (ret) {
> +		dev_err(dev, "reset failed\n");
> +		return ret;
> +	}
> +
> +	ret = vadc_measure_ref_points(vadc);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->dev.parent = dev;
> +	indio_dev->dev.of_node = node;
> +	indio_dev->name = pdev->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &vadc_info;
> +	indio_dev->channels = vadc->iio_chans;
> +	indio_dev->num_channels = vadc->nchannels;
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static const struct of_device_id vadc_match_table[] = {
> +	{ .compatible = "qcom,spmi-vadc" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, vadc_match_table);
> +
> +static struct platform_driver vadc_driver = {
> +	.driver = {
> +		   .name = "qcom-spmi-vadc",
> +		   .of_match_table = vadc_match_table,
> +	},
> +	.probe = vadc_probe,
> +};
> +module_platform_driver(vadc_driver);
> +
> +MODULE_ALIAS("platform:qcom-spmi-vadc");
> +MODULE_DESCRIPTION("Qualcomm SPMI PMIC voltage ADC driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Stanimir Varbanov <svarbanov@mm-sol.com>");
> +MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");
> --
> 1.9.1
> 

Re: [PATCH v5 1/2] DT: iio: vadc: document dt binding

[Ivan T. Ivanov]

On Wed, 2015-01-28 at 18:45 +0000, Jonathan Cameron wrote:
> On 20/01/15 10:15, Ivan T. Ivanov wrote:
> > From: Stanimir Varbanov <svarbanov@mm-sol.com>
> > 
> > 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>
> Given the only changes since the previous version (back in
> November are trivial typo corrections) I'm deeming this
> to have met the 3 weeks waiting for any DT responses and
> taking it through IIO.
> 
> Applied to the togreg branch of iio.git - initially pushed out
> as testing.

Thank you,
Ivan

Re: [PATCH v5 1/2] DT: iio: vadc: document dt binding

[Ivan T. Ivanov]

On Wed, 2015-01-28 at 18:45 +0000, Jonathan Cameron wrote:
> On 20/01/15 10:15, Ivan T. Ivanov wrote:
> > From: Stanimir Varbanov <svarbanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> > 
> > Document DT binding for Qualcomm SPMI PMIC voltage ADC
> > driver.
> > 
> > Signed-off-by: Stanimir Varbanov <svarbanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> > Signed-off-by: Ivan T. Ivanov <iivanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> Given the only changes since the previous version (back in
> November are trivial typo corrections) I'm deeming this
> to have met the 3 weeks waiting for any DT responses and
> taking it through IIO.
> 
> Applied to the togreg branch of iio.git - initially pushed out
> as testing.

Thank you,
Ivan

Re: [PATCH v5 2/2] iio: vadc: Qualcomm SPMI PMIC voltage ADC driver

[Ivan T. Ivanov]

On Wed, 2015-01-28 at 18:46 +0000, Jonathan Cameron wrote:
> On 20/01/15 10:15, Ivan T. Ivanov wrote:
> > From: Stanimir Varbanov <svarbanov@mm-sol.com>
> > 
> > The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
> > 15bits resolution and register space inside PMIC accessible across
> > SPMI bus.
> > 
> > The vadc driver registers itself through IIO interface.
> > 
> > Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
> > Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
> One minor comment inline.  Looks good to me.
> Applied to the togreg branch of iio.git - initially pushed out as testing.
> 
> Glad to have this one out of the pending list ;)

Thank you.

> 
> > +
> > +       irq_eoc = platform_get_irq(pdev, 0);
> > +       if (irq_eoc < 0) {
> > +               if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
> > +                       return irq_eoc;
> This does feel a little backwards.  I'd normally expect to see those
> errors that indicate one is not specified tested against, rather than
> trying to guess all the reasons it might fail otherwise....
> 
> This way round strikes me as probably more fragile as additional errors
> may turn up in that function over time..
> 

Agree, would it be better if driver just check for EPROBE_DEFER
and treat all other error codes as "no interrupt defined"? 
I could send followup patch if you like.

Regards,
Ivan

Re: [PATCH v5 2/2] iio: vadc: Qualcomm SPMI PMIC voltage ADC driver

[Ivan T. Ivanov]

On Wed, 2015-01-28 at 18:46 +0000, Jonathan Cameron wrote:
> On 20/01/15 10:15, Ivan T. Ivanov wrote:
> > From: Stanimir Varbanov <svarbanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> > 
> > The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
> > 15bits resolution and register space inside PMIC accessible across
> > SPMI bus.
> > 
> > The vadc driver registers itself through IIO interface.
> > 
> > Signed-off-by: Stanimir Varbanov <svarbanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> > Signed-off-by: Ivan T. Ivanov <iivanov-NEYub+7Iv8PQT0dZR+AlfA@public.gmane.org>
> One minor comment inline.  Looks good to me.
> Applied to the togreg branch of iio.git - initially pushed out as testing.
> 
> Glad to have this one out of the pending list ;)

Thank you.

> 
> > +
> > +       irq_eoc = platform_get_irq(pdev, 0);
> > +       if (irq_eoc < 0) {
> > +               if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
> > +                       return irq_eoc;
> This does feel a little backwards.  I'd normally expect to see those
> errors that indicate one is not specified tested against, rather than
> trying to guess all the reasons it might fail otherwise....
> 
> This way round strikes me as probably more fragile as additional errors
> may turn up in that function over time..
> 

Agree, would it be better if driver just check for EPROBE_DEFER
and treat all other error codes as "no interrupt defined"? 
I could send followup patch if you like.

Regards,
Ivan

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