[2/2] iio: adc: add a driver for Qualcomm PM8xxx HK/XOADC

Message ID 20170223133027.4730-1-linus.walleij@linaro.org
State New
Headers show
Series
  • Untitled series #562
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Commit Message

Linus Walleij Feb. 23, 2017, 1:30 p.m.
The Qualcomm PM8xxx PMICs contain a simpler ADC than its
successors (already in the kernel as qcom-spmi-vadc.c):
the HK/XO ADC (Housekeeping/Chrystal oscillator ADC).

As far as I can understand this is equal to the PMICs
using SSBI transport and encompass PM8018, PM8038,
PM8058, and PM8921, so this is shortly named PM8xxx.

This ADC monitors a bunch of on-board voltages and the die
temperature of the PMIC itself, but it can also be routed
to convert a few external MPPs (multi-purpose pins). On
the APQ8060 DragonBoard this feature is used to let this
ADC convert an analog ALS (Ambient Light Sensor) voltage
signal from a Capella CM3605 ALS into a LUX value.

Developed and tested with APQ8060 DragonBoard based on
Ivan's driver and Rama Krishna's patches. The SPMI VADC
driver is quite different, but share enough minor
functionality that I have split out to the common file
in a previous patch.

Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: Ivan T. Ivanov <iivanov.xz@gmail.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Rama Krishna Phani A <rphani@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
ChangeLog v4->v5:
- Fix the kbuild for allmod and allyes builds by creating a -core
  and -common object and baking them together into the final
  object.
- Add a per-variant information container instead of just adding
  a list of channels to the match data. Use this variant
  information throughout the code to support the variations.
- Incorporate new information from Björn and Stephen about how the
  channels actually work on the different variants. PM8058 has 16
  channels that can be muxed to different sources, so an AMUX
  setting each.
- Rebase on build fixes.
ChangeLog v3->v4:
- Only reposting this patch as the DT bindings and refactorings
  are merged.
- Prefix all channel names with PM8XXX_* to avoid namespace clashes.
- Use the compatible string to name the IIO device for greater
  model precision.
- Fix up a few excess newlines.
ChangeLog v2->v3:
- Rebase using Rama Krishna's improvements, set up defaults for
  scaling function and prescaler for each channel, per ASIC variant.
- Also set up RSV per-variant as the vendor tree does this and
  it seems necessary to set RSV0 on the muxoff channel to get
  readings from the XO thermistor.
- Encode default IIO type in the default per-PMIC channel table.
- Fixed a bug in ratiometric calibration (needed to force ratiometric
  mode).
- Dropped PM8917: that doesn't have any XOADC.
- Added a special flag for the PM8058: it apparently needs special
  RSV muxing due to being necessarily different.
- Augmented to handle altered ratiometric DT property.
- Do not hardcode that the reference voltage must be 2.2V, just fetch
  and enable the regulator. Different PMICs use different reference
  voltages.
ChangeLog v1->v2:
- Introduce a mutex to avoid different clients stepping on each others'
  toes
- Add an of_xlate function to be sure to match the right ADC
- Add all compatible strings, not just PM8058
---
 drivers/iio/adc/Kconfig                  |  10 +
 drivers/iio/adc/Makefile                 |   2 +
 drivers/iio/adc/qcom-pm8xxx-xoadc-core.c | 988 +++++++++++++++++++++++++++++++
 3 files changed, 1000 insertions(+)
 create mode 100644 drivers/iio/adc/qcom-pm8xxx-xoadc-core.c

-- 
2.9.3

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Patch

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 817693a14eb9..3184e36b1987 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -421,6 +421,16 @@  config PALMAS_GPADC
 	  is used in smartphones and tablets and supports a 16 channel
 	  general purpose ADC.
 
+config QCOM_PM8XXX_XOADC
+	tristate "Qualcomm SSBI PM8xxx PMIC XOADCs"
+	depends on MFD_PM8XXX
+	help
+	  ADC driver for the XOADC portions of the Qualcomm PM8xxx PMICs
+	  using SSBI transport: PM8018, PM8038, PM8058, PM8921.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called qcom-pm8xxx-xoadc.
+
 config QCOM_SPMI_IADC
 	tristate "Qualcomm SPMI PMIC current ADC"
 	depends on SPMI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index e70e578bbeea..c8724f2e1e18 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -43,6 +43,8 @@  obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 qcom-spmi-vadc-y := qcom-vadc-common.o qcom-spmi-vadc-core.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
+qcom-pm8xxx-xoadc-y := qcom-vadc-common.o qcom-pm8xxx-xoadc-core.o
+obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
 obj-$(CONFIG_STX104) += stx104.o
 obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc-core.c b/drivers/iio/adc/qcom-pm8xxx-xoadc-core.c
new file mode 100644
index 000000000000..d50b77ed9d2e
--- /dev/null
+++ b/drivers/iio/adc/qcom-pm8xxx-xoadc-core.c
@@ -0,0 +1,988 @@ 
+/*
+ * Qualcomm PM8xxx PMIC XOADC driver
+ *
+ * These ADCs are known as HK/XO (house keeping / chrystal oscillator)
+ * "XO" in "XOADC" means Chrystal Oscillator. It's a bunch of
+ * specific-purpose and general purpose ADC converters and channels.
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/regulator/consumer.h>
+
+#include "qcom-vadc-common.h"
+
+/*
+ * Definitions for the "user processor" registers lifted from the v3.4
+ * Qualcomm tree. Their kernel has two out-of-tree drivers for the ADC:
+ * drivers/misc/pmic8058-xoadc.c
+ * drivers/hwmon/pm8xxx-adc.c
+ * None of them contain any complete register specification, so this is
+ * a best effort of combining the information.
+ */
+
+/* These appear to be "battery monitor" registers */
+#define ADC_ARB_BTM_CNTRL1			0x17e
+#define ADC_ARB_BTM_CNTRL1_EN_BTM		BIT(0)
+#define ADC_ARB_BTM_CNTRL1_SEL_OP_MODE		BIT(1)
+#define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL1	BIT(2)
+#define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL2	BIT(3)
+#define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL3	BIT(4)
+#define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL4	BIT(5)
+#define ADC_ARB_BTM_CNTRL1_EOC			BIT(6)
+#define ADC_ARB_BTM_CNTRL1_REQ			BIT(7)
+
+#define ADC_ARB_BTM_AMUX_CNTRL			0x17f
+#define ADC_ARB_BTM_ANA_PARAM			0x180
+#define ADC_ARB_BTM_DIG_PARAM			0x181
+#define ADC_ARB_BTM_RSV				0x182
+#define ADC_ARB_BTM_DATA1			0x183
+#define ADC_ARB_BTM_DATA0			0x184
+#define ADC_ARB_BTM_BAT_COOL_THR1		0x185
+#define ADC_ARB_BTM_BAT_COOL_THR0		0x186
+#define ADC_ARB_BTM_BAT_WARM_THR1		0x187
+#define ADC_ARB_BTM_BAT_WARM_THR0		0x188
+#define ADC_ARB_BTM_CNTRL2			0x18c
+
+/* Proper ADC registers */
+
+#define ADC_ARB_USRP_CNTRL			0x197
+#define ADC_ARB_USRP_CNTRL_EN_ARB		BIT(0)
+#define ADC_ARB_USRP_CNTRL_RSV1			BIT(1)
+#define ADC_ARB_USRP_CNTRL_RSV2			BIT(2)
+#define ADC_ARB_USRP_CNTRL_RSV3			BIT(3)
+#define ADC_ARB_USRP_CNTRL_RSV4			BIT(4)
+#define ADC_ARB_USRP_CNTRL_RSV5			BIT(5)
+#define ADC_ARB_USRP_CNTRL_EOC			BIT(6)
+#define ADC_ARB_USRP_CNTRL_REQ			BIT(7)
+
+#define ADC_ARB_USRP_AMUX_CNTRL			0x198
+#define ADC_ARB_USRP_AMUX_CNTRL_RSV0		BIT(0)
+#define ADC_ARB_USRP_AMUX_CNTRL_RSV1		BIT(1)
+#define ADC_ARB_USRP_AMUX_CNTRL_PREMUX0		BIT(2)
+#define ADC_ARB_USRP_AMUX_CNTRL_PREMUX1		BIT(3)
+#define ADC_ARB_USRP_AMUX_CNTRL_SEL0		BIT(4)
+#define ADC_ARB_USRP_AMUX_CNTRL_SEL1		BIT(5)
+#define ADC_ARB_USRP_AMUX_CNTRL_SEL2		BIT(6)
+#define ADC_ARB_USRP_AMUX_CNTRL_SEL3		BIT(7)
+#define ADC_AMUX_PREMUX_SHIFT			2
+#define ADC_AMUX_SEL_SHIFT			4
+
+/* We know very little about the bits in this register */
+#define ADC_ARB_USRP_ANA_PARAM			0x199
+#define ADC_ARB_USRP_ANA_PARAM_DIS		0xFE
+#define ADC_ARB_USRP_ANA_PARAM_EN		0xFF
+
+#define ADC_ARB_USRP_DIG_PARAM			0x19A
+#define ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0	BIT(0)
+#define ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1	BIT(1)
+#define ADC_ARB_USRP_DIG_PARAM_CLK_RATE0	BIT(2)
+#define ADC_ARB_USRP_DIG_PARAM_CLK_RATE1	BIT(3)
+#define ADC_ARB_USRP_DIG_PARAM_EOC		BIT(4)
+/*
+ * On a later ADC the decimation factors are defined as
+ * 00 = 512, 01 = 1024, 10 = 2048, 11 = 4096 so assume this
+ * holds also for this older XOADC.
+ */
+#define ADC_ARB_USRP_DIG_PARAM_DEC_RATE0	BIT(5)
+#define ADC_ARB_USRP_DIG_PARAM_DEC_RATE1	BIT(6)
+#define ADC_ARB_USRP_DIG_PARAM_EN		BIT(7)
+#define ADC_DIG_PARAM_DEC_SHIFT			5
+
+#define ADC_ARB_USRP_RSV			0x19B
+#define ADC_ARB_USRP_RSV_RST			BIT(0)
+#define ADC_ARB_USRP_RSV_DTEST0			BIT(1)
+#define ADC_ARB_USRP_RSV_DTEST1			BIT(2)
+#define ADC_ARB_USRP_RSV_OP			BIT(3)
+#define ADC_ARB_USRP_RSV_IP_SEL0		BIT(4)
+#define ADC_ARB_USRP_RSV_IP_SEL1		BIT(5)
+#define ADC_ARB_USRP_RSV_IP_SEL2		BIT(6)
+#define ADC_ARB_USRP_RSV_TRM			BIT(7)
+#define ADC_RSV_IP_SEL_SHIFT			4
+
+#define ADC_ARB_USRP_DATA0			0x19D
+#define ADC_ARB_USRP_DATA1			0x19C
+
+/**
+ * Physical channels, they are amux channels in the analog muxer.
+ * The vendor tree call these "channel path type" for some reason, they
+ * have pretty much hardwired characteristics, apart from a few that are
+ * routed to a second mux for use with MPPs (multi-purpose-pins).
+ * Channel info:
+ *
+ * @PM8XXX_CHANNEL_VCOIN: Coincell backup power source
+ * @PM8XXX_CHANNEL_VBAT: Battery voltage
+ * @PM8XXX_CHANNEL_DCIN: Charger voltage
+ * @PM8XXX_CHANNEL_ICHG: Charger current monitor
+ * @PM8XXX_CHANNEL_VPH_PWR: Main system power VPH
+ * @PM8XXX_CHANNEL_AMUX5: general purpose, used for headset detection on some
+ * set-ups
+ * @PM8XXX_CHANNEL_AMUX6: general purpose, used for battery temperature on some
+ * set-ups
+ * @PM8XXX_CHANNEL_AMUX7: general purpose, used for system temperature on some
+ * set-ups
+ * @PM8XXX_CHANNEL_AMUX8: general purpose, used for battery ID detection on
+ * some set-ups
+ * @PM8XXX_CHANNEL_AMUX9: general purpose, used for external charger current on
+ * some set-ups
+ * @PM8XXX_CHANNEL_USB_VBUS: USB bus voltage, used for USB charging
+ * @PM8XXX_CHANNEL_DIE_TEMP: PMIC die temperature
+ * @PM8XXX_CHANNEL_INTERNAL: 625mV reference channel
+ * @PM8XXX_CHANNEL_125V: 1250mV reference channel
+ * @PM8XXX_CHANNEL_INTERNAL_2: 325mV reference channel
+ * @PM8XXX_CHANNEL_MUXOFF: channel to reduce input load on mux, apparently also
+ * measures XO temperature
+ */
+#define PM8XXX_CHANNEL_VCOIN		0x0
+#define PM8XXX_CHANNEL_VBAT		0x1
+#define PM8XXX_CHANNEL_DCIN		0x2
+#define PM8XXX_CHANNEL_ICHG		0x3
+#define PM8XXX_CHANNEL_VPH_PWR		0x4
+#define PM8XXX_CHANNEL_AMUX5		0x5
+#define PM8XXX_CHANNEL_AMUX6		0x6
+#define PM8XXX_CHANNEL_AMUX7		0x7
+#define PM8XXX_CHANNEL_AMUX8		0x8
+#define PM8XXX_CHANNEL_AMUX9		0x9
+#define PM8XXX_CHANNEL_USB_VBUS		0xa
+#define PM8XXX_CHANNEL_DIE_TEMP		0xb
+#define PM8XXX_CHANNEL_INTERNAL		0xc
+#define PM8XXX_CHANNEL_125V		0xd
+#define PM8XXX_CHANNEL_INTERNAL_2	0xe
+#define PM8XXX_CHANNEL_MUXOFF		0xf
+
+#define XOADC_CHANNELS		16 /* 4 bits */
+
+/*
+ * PM8058 AMUX premux scaling, two bits. This is done of the channel before
+ * reaching the AMUX.
+ */
+#define PM8058_AMUX_PRESCALE_0 0x0 /* No scaling on the signal */
+#define PM8058_AMUX_PRESCALE_1 0x1 /* Unity scaling selected by the user */
+#define PM8058_AMUX_PRESCALE_1_DIV3 0x2 /* 1/3 prescaler on the input */
+
+/* Defines reference voltage for the XOADC */
+#define AMUX_RSV0 0x0 /* XO_IN/XOADC_GND, special selection to read XO temp */
+#define AMUX_RSV1 0x1 /* PMIC_IN/XOADC_GND */
+#define AMUX_RSV2 0x2 /* PMIC_IN/BMS_CSP */
+#define AMUX_RSV3 0x3 /* not used */
+#define AMUX_RSV4 0x4 /* XOADC_GND/XOADC_GND */
+#define AMUX_RSV5 0x5 /* XOADC_VREF/XOADC_GND */
+#define XOADC_RSV_MAX 5 /* 3 bits 0..7, 3 and 6,7 are invalid */
+
+/**
+ * struct xoadc_channel - encodes channel properties and defaults
+ * @datasheet_name: the hardwarename of this channel
+ * @prescale: the channels have hard-coded prescale ratios defined
+ * by the hardware, this tells us what it is
+ * @type: corresponding IIO channel type, usually IIO_VOLTAGE or
+ * IIO_TEMP
+ * @scale_fn_type: the liner interpolation etc to convert the
+ * ADC code to the value that IIO expects, in uV or millicelsius
+ * etc. This scale function can be pretty elaborate if different
+ * thermistors are connected or other hardware characteristics are
+ * deployed.
+ * @amux_ip_rsv: ratiometric scale value used by the analig muxer: this
+ * selects the reference voltage for ratiometric scaling
+ */
+struct xoadc_channel {
+	const char *datasheet_name;
+	const struct vadc_prescale_ratio prescale;
+	enum iio_chan_type type;
+	enum vadc_scale_fn_type scale_fn_type;
+	u8 amux_ip_rsv:3;
+};
+
+/**
+ * struct xoadc_variant - encodes the XOADC variant characteristics
+ * @name: name of this PMIC variant
+ * @channels: the hardware channels and respective settings and defaults
+ * @broken_ratiometric: if the PMIC has broken ratiometric scaling (this
+ * is a known problem on PM8058)
+ * @prescaling: this variant uses AMUX bits 2 & 3 for prescaling (PM8058)
+ * @second_level_mux: this variant uses AMUX bits 2 & 3 for a second level
+ * mux
+ */
+struct xoadc_variant {
+	const char name[16];
+	const struct xoadc_channel *channels;
+	bool broken_ratiometric;
+	bool prescaling;
+	bool second_level_mux;
+};
+
+#define XOADC_CHAN(_dname, _type, _prenum, _preden, _scale, _amip) 	\
+	[PM8XXX_CHANNEL_##_dname] = {					\
+		.datasheet_name = __stringify(_dname),			\
+		.prescale = { .num = _prenum, .den = _preden },		\
+		.type = _type,						\
+		.scale_fn_type = _scale,				\
+		.amux_ip_rsv = _amip,					\
+	}								\
+
+/*
+ * Taken from arch/arm/mach-msm/board-9615.c in the vendor tree:
+ * TODO: incomplete, needs testing.
+ */
+static const struct xoadc_channel pm8018_xoadc_channels[] = {
+	XOADC_CHAN(VCOIN, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VBAT, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VPH_PWR, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DIE_TEMP, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
+	/* Used for battery ID or battery temperature */
+	XOADC_CHAN(AMUX8, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV2),
+	XOADC_CHAN(INTERNAL, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(125V, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(MUXOFF, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
+};
+
+/*
+ * Taken from arch/arm/mach-msm/board-8930-pmic.c in the vendor tree:
+ * TODO: needs testing.
+ */
+static const struct xoadc_channel pm8038_xoadc_channels[] = {
+	XOADC_CHAN(VCOIN, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VBAT, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DCIN, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(ICHG, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VPH_PWR, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX5, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX6, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX7, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	/* AMUX8 used for battery temperature in most cases */
+	XOADC_CHAN(AMUX8, IIO_TEMP, 1, 1, SCALE_THERM_100K_PULLUP, AMUX_RSV2),
+	XOADC_CHAN(AMUX9, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(USB_VBUS, IIO_VOLTAGE, 1, 4, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DIE_TEMP, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
+	XOADC_CHAN(INTERNAL, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(125V, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(INTERNAL_2, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(MUXOFF, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
+};
+
+/*
+ * This was created by cross-referencing the vendor tree
+ * arch/arm/mach-msm/board-msm8x60.c msm_adc_channels_data[]
+ * with the "channel types" (first field) to find the right
+ * configuration for these channels on an MSM8x60 i.e. PM8058
+ * setup.
+ */
+static const struct xoadc_channel pm8058_xoadc_channels[] = {
+	XOADC_CHAN(VCOIN, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VBAT, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DCIN, IIO_VOLTAGE, 1, 10, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(ICHG, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VPH_PWR, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	/*
+	 * AMUX channels 5 thru 9 are referred to as MPP5 thru MPP9 in
+	 * some code and documentation. But they are really just 5
+	 * channels just like any other. They are connected to a switching
+	 * matrix where they can be routed to any of the MPPs, not just
+	 * 1-to-1 onto MPP5 thru 9, so naming them MPP5 thru MPP9 is
+	 * very confusing.
+	 */
+	XOADC_CHAN(AMUX5, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX6, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX7, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX8, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX9, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(USB_VBUS, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DIE_TEMP, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
+	XOADC_CHAN(INTERNAL, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(125V, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(INTERNAL_2, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(MUXOFF, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
+};
+
+/*
+ * The PM8921 is similar, this comes from the vendor tree
+ * board-flo-pmic.c (Nexus 7) and board-8064-pmic.c
+ * Notably the prescalers are differing.
+ */
+static const struct xoadc_channel pm8921_xoadc_channels[] = {
+	XOADC_CHAN(VCOIN, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(VBAT, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DCIN, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
+	/* channel "ICHG" is reserved and not used on PM8921 */
+	XOADC_CHAN(VPH_PWR, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
+	/* AMUX scaling is unknown, these scalings are a guess */
+	XOADC_CHAN(AMUX5, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX6, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(AMUX7, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	/* AMUX8 goes to pin BAT_THERM used for battery temperature */
+	XOADC_CHAN(AMUX8, IIO_TEMP, 1, 1, SCALE_THERM_100K_PULLUP, AMUX_RSV1),
+	/* AMUX9 goes to pin BAT_ID used for battery ID detection */
+	XOADC_CHAN(AMUX9, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(USB_VBUS, IIO_VOLTAGE, 1, 4, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(DIE_TEMP, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
+	XOADC_CHAN(INTERNAL, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(125V, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	/*
+	 * This channel is used for charger temperature on PM8921, scaling
+	 * unknown
+	 */
+	XOADC_CHAN(INTERNAL_2, IIO_TEMP, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
+	XOADC_CHAN(MUXOFF, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
+};
+
+/**
+ * struct pm8xxx_chan_info - ADC channel information
+ * @name: name of this channel
+ * @calibration: whether to use absolute or ratiometric calibration
+ * @scale_fn_type: scaling function type
+ * @amux_channel: channel 0..15
+ * @decimation: 0,1,2,3
+ * @amux_prescaling: AMUX channel, selects prescaling on some variants
+ * (those do not have premuxing)
+ * @amux_premux: AMUX premuxing, selects a second level MUX on some
+ * variants (those do not have prescaling)
+ * @amux_ip_rsv: ratiometric scale value if using ratiometric
+ * calibration: 0, 1, 2, 4, 5.
+ */
+struct pm8xxx_chan_info {
+	const char *name;
+	enum vadc_calibration calibration;
+	const struct vadc_prescale_ratio *prescale;
+	enum vadc_scale_fn_type scale_fn_type;
+	u8 amux_channel:4;
+	u8 decimation:2;
+	u8 amux_prescaling:2;
+	u8 amux_premux:2;
+	u8 amux_ip_rsv:3;
+};
+
+/**
+ * struct pm8xxx_xoadc - state container for the XOADC
+ * @dev: pointer to device
+ * @map: regmap to access registers
+ * @vref: reference voltage regulator
+ * characteristics of the channels, and sensible default settings
+ * @nchans: number of channels, configured by the device tree
+ * @chans: the channel information per-channel, configured by the device tree
+ * @iio_chans: IIO channel specifiers
+ * @graph: linear calibration parameters for absolute and
+ * ratiometric measurements
+ * @complete: completion to indicate end of conversion
+ * @lock: lock to restrict access to the hardware to one client at the time
+ */
+struct pm8xxx_xoadc {
+	struct device *dev;
+	struct regmap *map;
+	const struct xoadc_variant *variant;
+	struct regulator *vref;
+	unsigned int nchans;
+	struct pm8xxx_chan_info *chans;
+	struct iio_chan_spec *iio_chans;
+	struct vadc_linear_graph graph[2];
+	struct completion complete;
+	struct mutex lock;
+};
+
+static irqreturn_t pm8xxx_eoc_irq(int irq, void *d)
+{
+	struct iio_dev *indio_dev = d;
+	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
+
+	complete(&adc->complete);
+
+	return IRQ_HANDLED;
+}
+
+static struct pm8xxx_chan_info *
+pm8xxx_get_channel(struct pm8xxx_xoadc *adc, u8 chan)
+{
+	struct pm8xxx_chan_info *ch;
+	int i;
+
+	for (i = 0; i < adc->nchans; i++) {
+		ch = &adc->chans[i];
+		if (ch->amux_channel == chan)
+			break;
+	}
+	if (i == adc->nchans)
+		return NULL;
+
+	return ch;
+}
+
+static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
+				   const struct pm8xxx_chan_info *ch,
+				   u8 rsv, u16 *adc_code,
+				   bool force_ratiometric)
+{
+	int ret;
+	unsigned int val;
+	u8 rsvmask, rsvval;
+	u8 lsb, msb;
+
+	dev_dbg(adc->dev, "read channel \"%s\", amux %d, prescale %d, rsv %d\n",
+		ch->name, ch->amux_channel, ch->amux_prescaling, rsv);
+
+	mutex_lock(&adc->lock);
+
+	/* Mux in this channel */
+	val = ch->amux_channel << ADC_AMUX_SEL_SHIFT;
+	if (adc->variant->prescaling)
+		val |= ch->amux_prescaling << ADC_AMUX_PREMUX_SHIFT;
+	if (adc->variant->second_level_mux)
+		val |= ch->amux_premux << ADC_AMUX_PREMUX_SHIFT;
+
+	ret = regmap_write(adc->map, ADC_ARB_USRP_AMUX_CNTRL, val);
+	if (ret)
+		goto unlock;
+
+	/* Set up ratiometric scale value, mask off all bits except these */
+	rsvmask = (ADC_ARB_USRP_RSV_RST | ADC_ARB_USRP_RSV_DTEST0 |
+		   ADC_ARB_USRP_RSV_DTEST1 | ADC_ARB_USRP_RSV_OP);
+	if (adc->variant->broken_ratiometric && !force_ratiometric) {
+		/*
+		 * Apparently the PM8058 has some kind of bug which is
+		 * reflected in the vendor tree drivers/misc/pmix8058-xoadc.c
+		 * which just hardcodes the RSV selector to SEL1 (0x20) for
+		 * most cases and SEL0 (0x10) for the MUXOFF channel only.
+		 * If we force ratiometric (currently only done when attempting
+		 * to do ratiometric calibration) this doesn't seem to work
+		 * very well and I suspect ratiometric conversion is simply
+		 * broken or not supported on the PM8058.
+		 *
+		 * Maybe IO_SEL2 doesn't exist on PM8058 and bits 4 & 5 select
+		 * the mode alone.
+		 *
+		 * Some PM8058 register documentation would be nice to get
+		 * this right.
+		 */
+		if (ch->amux_channel == PM8XXX_CHANNEL_MUXOFF)
+			rsvval = ADC_ARB_USRP_RSV_IP_SEL0;
+		else
+			rsvval = ADC_ARB_USRP_RSV_IP_SEL1;
+	} else {
+		if (rsv == 0xff)
+			rsvval = (ch->amux_ip_rsv << ADC_RSV_IP_SEL_SHIFT) |
+				ADC_ARB_USRP_RSV_TRM;
+		else
+			rsvval = (rsv << ADC_RSV_IP_SEL_SHIFT) |
+				ADC_ARB_USRP_RSV_TRM;
+	}
+
+	ret = regmap_update_bits(adc->map,
+				 ADC_ARB_USRP_RSV,
+				 ~rsvmask,
+				 rsvval);
+	if (ret)
+		goto unlock;
+
+	ret = regmap_write(adc->map, ADC_ARB_USRP_ANA_PARAM,
+			   ADC_ARB_USRP_ANA_PARAM_DIS);
+	if (ret)
+		goto unlock;
+
+	/* Decimation factor */
+	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
+			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
+			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
+			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
+	if (ret)
+		goto unlock;
+
+	ret = regmap_write(adc->map, ADC_ARB_USRP_ANA_PARAM,
+			   ADC_ARB_USRP_ANA_PARAM_EN);
+	if (ret)
+		goto unlock;
+
+	/* Enable the arbiter, the Qualcomm code does it twice like this */
+	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
+			   ADC_ARB_USRP_CNTRL_EN_ARB);
+	if (ret)
+		goto unlock;
+	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
+			   ADC_ARB_USRP_CNTRL_EN_ARB);
+	if (ret)
+		goto unlock;
+
+
+	/* Fire a request! */
+	reinit_completion(&adc->complete);
+	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
+			   ADC_ARB_USRP_CNTRL_EN_ARB |
+			   ADC_ARB_USRP_CNTRL_REQ);
+	if (ret)
+		goto unlock;
+
+	/* Next the interrupt occurs */
+	ret = wait_for_completion_timeout(&adc->complete,
+					  VADC_CONV_TIME_MAX_US);
+	if (!ret) {
+		dev_err(adc->dev, "conversion timed out\n");
+		ret = -ETIMEDOUT;
+		goto unlock;
+	}
+
+	ret = regmap_read(adc->map, ADC_ARB_USRP_DATA0, &val);
+	if (ret)
+		goto unlock;
+	lsb = val;
+	ret = regmap_read(adc->map, ADC_ARB_USRP_DATA1, &val);
+	if (ret)
+		goto unlock;
+	msb = val;
+	*adc_code = (msb << 8) | lsb;
+
+	/* Turn off the ADC by setting the arbiter to 0 twice */
+	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL, 0);
+	if (ret)
+		goto unlock;
+	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL, 0);
+	if (ret)
+		goto unlock;
+
+unlock:
+	mutex_unlock(&adc->lock);
+	return ret;
+}
+
+static int pm8xxx_read_channel(struct pm8xxx_xoadc *adc,
+			       const struct pm8xxx_chan_info *ch,
+			       u16 *adc_code)
+{
+	/*
+	 * Normally we just use the ratiometric scale value (RSV) predefined
+	 * for the channel, but during calibration we need to modify this
+	 * so this wrapper is a helper hiding the more complex version.
+	 */
+	return pm8xxx_read_channel_rsv(adc, ch, 0xff, adc_code, false);
+}
+
+static int pm8xxx_calibrate_device(struct pm8xxx_xoadc *adc)
+{
+	const struct pm8xxx_chan_info *ch;
+	u16 read_1250v;
+	u16 read_0625v;
+	u16 read_nomux_rsv5;
+	u16 read_nomux_rsv4;
+	int ret;
+
+	adc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
+	adc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE;
+
+	/* Common reference channel calibration */
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_125V);
+	if (!ch)
+		return -ENODEV;
+	ret = pm8xxx_read_channel(adc, ch, &read_1250v);
+	if (ret) {
+		dev_err(adc->dev, "could not read 1.25V reference channel\n");
+		return -ENODEV;
+	}
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_INTERNAL);
+	if (!ch)
+		return -ENODEV;
+	ret = pm8xxx_read_channel(adc, ch, &read_0625v);
+	if (ret) {
+		dev_err(adc->dev, "could not read 0.625V reference channel\n");
+		return -ENODEV;
+	}
+	if (read_1250v == read_0625v) {
+		dev_err(adc->dev, "read same ADC code for 1.25V and 0.625V\n");
+		return -ENODEV;
+	}
+
+	adc->graph[VADC_CALIB_ABSOLUTE].dy = read_1250v - read_0625v;
+	adc->graph[VADC_CALIB_ABSOLUTE].gnd = read_0625v;
+
+	dev_info(adc->dev, "absolute calibration dx = %d uV, dy = %d units\n",
+		 VADC_ABSOLUTE_RANGE_UV, adc->graph[VADC_CALIB_ABSOLUTE].dy);
+
+	/* Ratiometric calibration */
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_MUXOFF);
+	if (!ch)
+		return -ENODEV;
+	ret = pm8xxx_read_channel_rsv(adc, ch, AMUX_RSV5,
+				      &read_nomux_rsv5, true);
+	if (ret) {
+		dev_err(adc->dev, "could not read MUXOFF reference channel\n");
+		return -ENODEV;
+	}
+	ret = pm8xxx_read_channel_rsv(adc, ch, AMUX_RSV4,
+				      &read_nomux_rsv4, true);
+	if (ret) {
+		dev_err(adc->dev, "could not read MUXOFF reference channel\n");
+		return -ENODEV;
+	}
+	adc->graph[VADC_CALIB_RATIOMETRIC].dy =
+		read_nomux_rsv5 - read_nomux_rsv4;
+	adc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_nomux_rsv4;
+
+	dev_info(adc->dev, "ratiometric calibration dx = %d, dy = %d units\n",
+		 VADC_RATIOMETRIC_RANGE,
+		 adc->graph[VADC_CALIB_RATIOMETRIC].dy);
+
+	return 0;
+}
+
+static int pm8xxx_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
+	const struct pm8xxx_chan_info *ch;
+	u16 adc_code;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ch = pm8xxx_get_channel(adc, chan->address);
+		if (!ch) {
+			dev_err(adc->dev, "no such channel %lu\n",
+				chan->address);
+			return -EINVAL;
+		}
+		ret = pm8xxx_read_channel(adc, ch, &adc_code);
+		if (ret)
+			return ret;
+
+		ret = qcom_vadc_scale(ch->scale_fn_type,
+				      &adc->graph[ch->calibration],
+				      ch->prescale,
+				      (ch->calibration == VADC_CALIB_ABSOLUTE),
+				      adc_code, val);
+		if (ret)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_RAW:
+		ch = pm8xxx_get_channel(adc, chan->address);
+		if (!ch) {
+			dev_err(adc->dev, "no such channel %lu\n",
+				chan->address);
+			return -EINVAL;
+		}
+		ret = pm8xxx_read_channel(adc, ch, &adc_code);
+		if (ret)
+			return ret;
+
+		*val = (int)adc_code;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int pm8xxx_of_xlate(struct iio_dev *indio_dev,
+			   const struct of_phandle_args *iiospec)
+{
+	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
+	unsigned int i;
+
+	for (i = 0; i < adc->nchans; i++)
+		if (adc->iio_chans[i].channel == iiospec->args[0])
+			return i;
+
+	return -EINVAL;
+}
+
+static const struct iio_info pm8xxx_xoadc_info = {
+	.driver_module = THIS_MODULE,
+	.of_xlate = pm8xxx_of_xlate,
+	.read_raw = pm8xxx_read_raw,
+};
+
+static int pm8xxx_xoadc_parse_channel(struct device *dev,
+				      struct device_node *np,
+				      const struct xoadc_channel *hw_channels,
+				      struct iio_chan_spec *iio_chan,
+				      struct pm8xxx_chan_info *ch)
+{
+	const char *name = np->name;
+	u32 chan, rsv, dec;
+	int ret;
+
+	ret = of_property_read_u32(np, "reg", &chan);
+	if (ret) {
+		dev_err(dev, "invalid channel number %s\n", name);
+		return ret;
+	}
+	if (chan >= XOADC_CHANNELS) {
+		dev_err(dev, "%s too big channel number %d\n", name, chan);
+		return -EINVAL;
+	}
+
+	/* Look up default channel settings */
+	ch->amux_channel = chan;
+	ch->name = name;
+	ch->prescale = &hw_channels[chan].prescale;
+	ch->scale_fn_type = hw_channels[chan].scale_fn_type;
+	ch->amux_ip_rsv = hw_channels[chan].amux_ip_rsv;
+	/* Everyone seems to use absolute calibration except in special cases */
+	ch->calibration = VADC_CALIB_ABSOLUTE;
+	/* Everyone seems to use default ("type 2") decimation */
+	ch->decimation = VADC_DEF_DECIMATION;
+	/*
+	 * Everyone seems to use this 1-to-1 premux scaling channel on
+	 * PM8058.
+	 * FIXME: on PM8921 the "premux" bits instead selects a second level
+	 * mux.
+	 */
+	ch->amux_prescaling = PM8058_AMUX_PRESCALE_0;
+
+	if (!of_property_read_u32(np, "qcom,ratiometric", &rsv)) {
+		ch->calibration = VADC_CALIB_RATIOMETRIC;
+		if (rsv > XOADC_RSV_MAX) {
+			dev_err(dev, "%s too large RSV value %d\n", name, rsv);
+			return -EINVAL;
+		}
+		if (rsv == AMUX_RSV3) {
+			dev_err(dev, "%s invalid RSV value %d\n", name, rsv);
+			return -EINVAL;
+		}
+	}
+
+	/* Optional decimation, if omitted we use the default */
+	ret = of_property_read_u32(np, "qcom,decimation", &dec);
+	if (!ret) {
+		ret = qcom_vadc_decimation_from_dt(dec);
+		if (ret < 0) {
+			dev_err(dev, "%s invalid decimation %d\n",
+				name, dec);
+			return ret;
+		}
+		ch->decimation = ret;
+	}
+
+	iio_chan->channel = ch->amux_channel;
+	iio_chan->address = ch->amux_channel;
+	iio_chan->datasheet_name = ch->name;
+	iio_chan->type = hw_channels[chan].type;
+	/* All channels are raw or processed */
+	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_PROCESSED);
+	iio_chan->indexed = 1;
+
+	dev_dbg(dev, "channel %d \"%s\" ref voltage: %d, decimation %d "
+		"prescale %d/%d, scale function %d\n",
+		ch->amux_channel, ch->name, ch->amux_ip_rsv,
+		ch->decimation,	ch->prescale->num, ch->prescale->den,
+		ch->scale_fn_type);
+
+	return 0;
+}
+
+static int pm8xxx_xoadc_parse_channels(struct pm8xxx_xoadc *adc,
+				       struct device_node *np)
+{
+	struct device_node *child;
+	struct pm8xxx_chan_info *ch;
+	int ret;
+	int i;
+
+	adc->nchans = of_get_available_child_count(np);
+	if (!adc->nchans) {
+		dev_err(adc->dev, "no channel children\n");
+		return -ENODEV;
+	}
+	dev_dbg(adc->dev, "found %d ADC channels\n", adc->nchans);
+
+	adc->iio_chans = devm_kcalloc(adc->dev, adc->nchans,
+				      sizeof(*adc->iio_chans), GFP_KERNEL);
+	if (!adc->iio_chans)
+		return -ENOMEM;
+
+	adc->chans = devm_kcalloc(adc->dev, adc->nchans,
+				  sizeof(*adc->chans), GFP_KERNEL);
+	if (!adc->chans)
+		return -ENOMEM;
+
+	i = 0;
+	for_each_available_child_of_node(np, child) {
+		ch = &adc->chans[i];
+		ret = pm8xxx_xoadc_parse_channel(adc->dev, child,
+						 adc->variant->channels,
+						 &adc->iio_chans[i],
+						 ch);
+		if (ret) {
+			of_node_put(child);
+			return ret;
+		}
+		i++;
+	}
+
+	/* Check for required channels */
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_125V);
+	if (!ch) {
+		dev_err(adc->dev, "missing 1.25V reference channel\n");
+		return -ENODEV;
+	}
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_INTERNAL);
+	if (!ch) {
+		dev_err(adc->dev, "missing 0.625V reference channel\n");
+		return -ENODEV;
+	}
+	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_MUXOFF);
+	if (!ch) {
+		dev_err(adc->dev, "missing MUXOFF reference channel\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int pm8xxx_xoadc_probe(struct platform_device *pdev)
+{
+	const struct xoadc_variant *variant;
+	struct pm8xxx_xoadc *adc;
+	struct iio_dev *indio_dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct regmap *map;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	variant = of_device_get_match_data(dev);
+	if (!variant)
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
+	if (!indio_dev)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, indio_dev);
+
+	adc = iio_priv(indio_dev);
+	adc->dev = dev;
+	adc->variant = variant;
+	init_completion(&adc->complete);
+	mutex_init(&adc->lock);
+
+	ret = pm8xxx_xoadc_parse_channels(adc, np);
+	if (ret)
+		return ret;
+
+	map = dev_get_regmap(dev->parent, NULL);
+	if (!map) {
+		dev_err(dev, "parent regmap unavailable.\n");
+		return -ENXIO;
+	}
+	adc->map = map;
+
+	/* Bring up regulator */
+	adc->vref = devm_regulator_get(dev, "xoadc-ref");
+	if (IS_ERR(adc->vref)) {
+		dev_err(dev, "failed to get XOADC VREF regulator\n");
+		return PTR_ERR(adc->vref);
+	}
+	ret = regulator_enable(adc->vref);
+	if (ret) {
+		dev_err(dev, "failed to enable XOADC VREF regulator\n");
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0),
+			pm8xxx_eoc_irq, NULL, 0, variant->name, indio_dev);
+	if (ret) {
+		dev_err(dev, "unable to request IRQ\n");
+		goto out_disable_vref;
+	}
+
+	indio_dev->dev.parent = dev;
+	indio_dev->dev.of_node = np;
+	indio_dev->name = variant->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &pm8xxx_xoadc_info;
+	indio_dev->channels = adc->iio_chans;
+	indio_dev->num_channels = adc->nchans;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto out_disable_vref;
+
+	ret = pm8xxx_calibrate_device(adc);
+	if (ret)
+		goto out_unreg_device;
+
+	dev_info(dev, "%s XOADC driver enabled\n", variant->name);
+
+	return 0;
+
+out_unreg_device:
+	iio_device_unregister(indio_dev);
+out_disable_vref:
+	regulator_disable(adc->vref);
+
+	return ret;
+}
+
+static int pm8xxx_xoadc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	regulator_disable(adc->vref);
+
+	return 0;
+}
+
+static const struct xoadc_variant pm8018_variant = {
+	.name = "PM8018-XOADC",
+	.channels = pm8018_xoadc_channels,
+};
+
+static const struct xoadc_variant pm8038_variant = {
+	.name = "PM8038-XOADC",
+	.channels = pm8038_xoadc_channels,
+};
+
+static const struct xoadc_variant pm8058_variant = {
+	.name = "PM8058-XOADC",
+	.channels = pm8058_xoadc_channels,
+	.broken_ratiometric = true,
+	.prescaling = true,
+};
+
+static const struct xoadc_variant pm8921_variant = {
+	.name = "PM8921-XOADC",
+	.channels = pm8921_xoadc_channels,
+	.second_level_mux = true,
+};
+
+static const struct of_device_id pm8xxx_xoadc_id_table[] = {
+	{
+		.compatible = "qcom,pm8018-adc",
+		.data = &pm8018_variant,
+	},
+	{
+		.compatible = "qcom,pm8038-adc",
+		.data = &pm8038_variant,
+	},
+	{
+		.compatible = "qcom,pm8058-adc",
+		.data = &pm8058_variant,
+	},
+	{
+		.compatible = "qcom,pm8921-adc",
+		.data = &pm8921_variant,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, pm8xxx_xoadc_id_table);
+
+static struct platform_driver pm8xxx_xoadc_driver = {
+	.driver		= {
+		.name	= "pm8xxx-adc",
+		.of_match_table = pm8xxx_xoadc_id_table,
+	},
+	.probe		= pm8xxx_xoadc_probe,
+	.remove		= pm8xxx_xoadc_remove,
+};
+module_platform_driver(pm8xxx_xoadc_driver);
+
+MODULE_DESCRIPTION("PM8xxx XOADC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:pm8xxx-xoadc");