Re: [PATCH 6/8 v2] iio: adc: New driver for the AB8500 GPADC

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 22 Aug 2019 16:52:31 +0200
Linus Walleij <linus.walleij@linaro.org> wrote:

> This is a new driver for the ST-Ericsson AB8500 GPADC, which
> replaces the old driver in drivers/mfd/ab8500-gpadc.c and
> thus gets rid of another necessarily different custom driver
> from the times before IIO existed.
> 
> The AB8500 GPADC can convert 10 different channels and these
> are used for monitoring voltages in the U8500 chipset, some
> are used for battery charging, some for temperature
> monitoring.
> 
> As this is very core functionality that a lot of drivers
> depend on and was formerly compiled in with the AB8500 core
> driver, we deafault it to 'y' in Kconfig: it can be compiled
> out but it is really not advisible: the platform can
> for example overheat if we do.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Good to see this come back ;)  I'll confess I've completely
forgotten it so will just do a fresh review as if it were
a v1.

Note we have standardized the specification of ADC channels since
v1.  See Documentation/devicetree/bindings/iio/adc/adc.txt
It's fairly similar to what you have though so easy tweak
to bindings. I don't think any change in here is needed.

Some minor stuff inline otherwise.
Fix those up and you can add
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

What is your merge plan for these?

Thanks,

Jonathan


> ---
> ChangeLog v1 -> v2:
> - Break out the IIO driver into a separate patch just adding
>   it instead of moving it in the same patch, this makes it
>   easier for the IIO maintainers to review the patch.
> - Rename a slew of variables and fix up comment syntax etc.
> - Drop the enums for sample numbers 1, 4, 8, 16 just use numerals.
> - Use a bool to indicate trigger on falling edge rather than a number.
> - Use a bool to indicate hardware conversion on a channel.
> - Use an enum for the channels.
> - Pass a pointer to the channel config struct instead of overly
>   talkative function prototype.
> - Use devm_iio_device_register()
> - Push the channels into the IIO device, do not keep a separate
>   copy of the IIO channels inside the driver state container.
> - Do not mark interrupts as shared. They are not shared.
> - Remove comments commenting the obvious.
> - Add prefixed to definitions and enums to avoid clashes with
>   other namespaces and make it obvious where things are coming
>   from.
> - Drop surplus local variable.
> - Drop unused OTP retrieveal function for AB8540.
> - Use runtime PM for system PM callbacks.
> - Use builtin_platform_driver() for initializing the driver as
>   this is a bool menuconfig.
> - Fix up processed reads from the ADC: I mistakedly dropped the
>   flag indicating we can do processed reads, falling us back to
>   just raw reads.
> ---
>  MAINTAINERS                    |    1 +
>  drivers/iio/adc/Kconfig        |   10 +
>  drivers/iio/adc/Makefile       |    1 +
>  drivers/iio/adc/ab8500-gpadc.c | 1240 ++++++++++++++++++++++++++++++++
>  4 files changed, 1252 insertions(+)
>  create mode 100644 drivers/iio/adc/ab8500-gpadc.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 43604d6ab96c..a2fee2f03530 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1978,6 +1978,7 @@ F:	drivers/dma/ste_dma40*
>  F:	drivers/hwspinlock/u8500_hsem.c
>  F:	drivers/i2c/busses/i2c-nomadik.c
>  F:	drivers/i2c/busses/i2c-stu300.c
> +F:	drivers/iio/adc/ab8500-gpadc.c
>  F:	drivers/mfd/ab3100*
>  F:	drivers/mfd/ab8500*
>  F:	drivers/mfd/abx500*
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7e3286265a38..fba7ddcdd8e2 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -6,6 +6,16 @@
>  
>  menu "Analog to digital converters"
>  
> +config AB8500_GPADC
> +	bool "ST-Ericsson AB8500 GPADC driver"
> +	depends on AB8500_CORE && REGULATOR_AB8500
> +	default y
> +	help
> +	  AB8500 Analog Baseband, mixed signal integrated circuit GPADC
> +	  (General Purpose Analog to Digital Converter) driver used to monitor
> +	  internal voltages, convert accessory and battery, AC (charger, mains)
> +	  and USB voltages integral to the U8500 platform.
> +
>  config AD_SIGMA_DELTA
>  	tristate
>  	select IIO_BUFFER
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index ef9cc485fb67..fc1b6ebb0cde 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -4,6 +4,7 @@
>  #
>  
>  # When adding new entries keep the list in alphabetical order
> +obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
>  obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
>  obj-$(CONFIG_AD7124) += ad7124.o
>  obj-$(CONFIG_AD7266) += ad7266.o
> diff --git a/drivers/iio/adc/ab8500-gpadc.c b/drivers/iio/adc/ab8500-gpadc.c
> new file mode 100644
> index 000000000000..e8abaf002c1c
> --- /dev/null
> +++ b/drivers/iio/adc/ab8500-gpadc.c
> @@ -0,0 +1,1240 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) ST-Ericsson SA 2010
> + *
> + * Author: Arun R Murthy <arun.murthy@stericsson.com>
> + * Author: Daniel Willerud <daniel.willerud@stericsson.com>
> + * Author: Johan Palsson <johan.palsson@stericsson.com>
> + * Author: M'boumba Cedric Madianga
> + * Author: Linus Walleij <linus.walleij@linaro.org>
> + *
> + * AB8500 General Purpose ADC driver. The AB8500 uses reference voltages:
> + * VinVADC, and VADC relative to GND to do its job. It monitors main and backup
> + * battery voltages, AC (mains) voltage, USB cable voltage, as well as voltages
> + * representing the temperature of the chip die and battery, accessory
> + * detection by resistance measurements using relative voltages and GSM burst
> + * information.
> + *
> + * Some of the voltages are measured on external pins on the IC, such as
> + * battery temperature or "ADC aux" 1 and 2. Other voltages are internal rails
> + * from other parts of the ASIC such as main charger voltage, main and battery
> + * backup voltage or USB VBUS voltage. For this reason drivers for other
> + * parts of the system are required to obtain handles to the ADC to do work
> + * for them and the IIO driver provides arbitration among these consumers.
> + */
> +#include <linux/init.h>
> +#include <linux/bits.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/spinlock.h>
> +#include <linux/delay.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/platform_device.h>
> +#include <linux/completion.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/random.h>
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/abx500.h>
> +#include <linux/mfd/abx500/ab8500.h>
> +
> +/* GPADC register offsets and bit definitions */
> +
> +#define AB8500_GPADC_CTRL1_REG		0x00
> +/* GPADC control register 1 bits */
> +#define AB8500_GPADC_CTRL1_DISABLE		0x00
> +#define AB8500_GPADC_CTRL1_ENABLE		BIT(0)
> +#define AB8500_GPADC_CTRL1_TRIG_ENA		BIT(1)
> +#define AB8500_GPADC_CTRL1_START_SW_CONV	BIT(2)
> +#define AB8500_GPADC_CTRL1_BTEMP_PULL_UP	BIT(3)
> +/* 0 = use rising edge, 1 = use falling edge */
> +#define AB8500_GPADC_CTRL1_TRIG_EDGE		BIT(4)
> +/* 0 = use VTVOUT, 1 = use VRTC as pull-up supply for battery temp NTC */
> +#define AB8500_GPADC_CTRL1_PUPSUPSEL		BIT(5)
> +#define AB8500_GPADC_CTRL1_BUF_ENA		BIT(6)
> +#define AB8500_GPADC_CTRL1_ICHAR_ENA		BIT(7)
> +
> +#define AB8500_GPADC_CTRL2_REG		0x01
> +#define AB8500_GPADC_CTRL3_REG		0x02
> +/*
> + * GPADC control register 2 and 3 bits
> + * the bit layout is the same for SW and HW conversion set-up
> + */
> +#define AB8500_GPADC_CTRL2_AVG_1		0x00
> +#define AB8500_GPADC_CTRL2_AVG_4		BIT(5)
> +#define AB8500_GPADC_CTRL2_AVG_8		BIT(6)
> +#define AB8500_GPADC_CTRL2_AVG_16		(BIT(5) | BIT(6))
> +
> +enum ab8500_gpadc_channel {
> +	AB8500_GPADC_CHAN_UNUSED = 0x00,
> +	AB8500_GPADC_CHAN_BAT_CTRL = 0x01,
> +	AB8500_GPADC_CHAN_BAT_TEMP = 0x02,
> +	/* This is not used on AB8505 */
> +	AB8500_GPADC_CHAN_MAIN_CHARGER = 0x03,
> +	AB8500_GPADC_CHAN_ACC_DET_1 = 0x04,
> +	AB8500_GPADC_CHAN_ACC_DET_2 = 0x05,
> +	AB8500_GPADC_CHAN_ADC_AUX_1 = 0x06,
> +	AB8500_GPADC_CHAN_ADC_AUX_2 = 0x07,
> +	AB8500_GPADC_CHAN_VBAT_A = 0x08,
> +	AB8500_GPADC_CHAN_VBUS = 0x09,
> +	AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT = 0x0a,
> +	AB8500_GPADC_CHAN_USB_CHARGER_CURRENT = 0x0b,
> +	AB8500_GPADC_CHAN_BACKUP_BAT = 0x0c,
> +	/* Only on AB8505 */
> +	AB8505_GPADC_CHAN_DIE_TEMP = 0x0d,
> +	AB8500_GPADC_CHAN_ID = 0x0e,
> +	AB8500_GPADC_CHAN_INTERNAL_TEST_1 = 0x0f,
> +	AB8500_GPADC_CHAN_INTERNAL_TEST_2 = 0x10,
> +	AB8500_GPADC_CHAN_INTERNAL_TEST_3 = 0x11,
> +	/* FIXME: Applicable to all ASIC variants? */
> +	AB8500_GPADC_CHAN_XTAL_TEMP = 0x12,
> +	AB8500_GPADC_CHAN_VBAT_TRUE_MEAS = 0x13,
> +	/* FIXME: Doesn't seem to work with pure AB8500 */
> +	AB8500_GPADC_CHAN_BAT_CTRL_AND_IBAT = 0x1c,
> +	AB8500_GPADC_CHAN_VBAT_MEAS_AND_IBAT = 0x1d,
> +	AB8500_GPADC_CHAN_VBAT_TRUE_MEAS_AND_IBAT = 0x1e,
> +	AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT = 0x1f,
> +	/*
> +	 * Virtual channel used only for ibat conversion to ampere.
> +	 * Battery current conversion (ibat) cannot be requested as a
> +	 * single conversion but it is always requested in combination
> +	 * with other input requests.
> +	 */
> +	AB8500_GPADC_CHAN_IBAT_VIRTUAL = 0xFF,
> +};
> +
> +#define AB8500_GPADC_AUTO_TIMER_REG	0x03
> +
> +#define AB8500_GPADC_STAT_REG		0x04
> +#define AB8500_GPADC_STAT_BUSY		BIT(0)
> +
> +#define AB8500_GPADC_MANDATAL_REG	0x05
> +#define AB8500_GPADC_MANDATAH_REG	0x06
> +#define AB8500_GPADC_AUTODATAL_REG	0x07
> +#define AB8500_GPADC_AUTODATAH_REG	0x08
> +#define AB8500_GPADC_MUX_CTRL_REG	0x09
> +#define AB8540_GPADC_MANDATA2L_REG	0x09
> +#define AB8540_GPADC_MANDATA2H_REG	0x0A
> +#define AB8540_GPADC_APEAAX_REG		0x10
> +#define AB8540_GPADC_APEAAT_REG		0x11
> +#define AB8540_GPADC_APEAAM_REG		0x12
> +#define AB8540_GPADC_APEAAH_REG		0x13
> +#define AB8540_GPADC_APEAAL_REG		0x14
> +
> +/*
> + * OTP register offsets
> + * Bank : 0x15
> + */
> +#define AB8500_GPADC_CAL_1	0x0F
> +#define AB8500_GPADC_CAL_2	0x10
> +#define AB8500_GPADC_CAL_3	0x11
> +#define AB8500_GPADC_CAL_4	0x12
> +#define AB8500_GPADC_CAL_5	0x13
> +#define AB8500_GPADC_CAL_6	0x14
> +#define AB8500_GPADC_CAL_7	0x15
> +/* New calibration for 8540 */
> +#define AB8540_GPADC_OTP4_REG_7	0x38
> +#define AB8540_GPADC_OTP4_REG_6	0x39
> +#define AB8540_GPADC_OTP4_REG_5	0x3A
> +
> +#define DIS_ZERO		0x00
> +#define EN_VBIAS_XTAL_TEMP	0x02
> +
> +/* GPADC constants from AB8500 spec, UM0836 */
> +#define ADC_RESOLUTION		1024

Prefix?

> +#define ADC_CH_BTEMP_MIN	0
> +#define ADC_CH_BTEMP_MAX	1350
> +#define ADC_CH_DIETEMP_MIN	0
> +#define ADC_CH_DIETEMP_MAX	1350
> +#define ADC_CH_CHG_V_MIN	0
> +#define ADC_CH_CHG_V_MAX	20030
> +#define ADC_CH_ACCDET2_MIN	0
> +#define ADC_CH_ACCDET2_MAX	2500
> +#define ADC_CH_VBAT_MIN		2300
> +#define ADC_CH_VBAT_MAX		4800
> +#define ADC_CH_CHG_I_MIN	0
> +#define ADC_CH_CHG_I_MAX	1500
> +#define ADC_CH_BKBAT_MIN	0
> +#define ADC_CH_BKBAT_MAX	3200
> +
> +/* GPADC constants from AB8540 spec */
> +#define ADC_CH_IBAT_MIN		(-6000) /* mA range measured by ADC for ibat */
> +#define ADC_CH_IBAT_MAX		6000
> +#define ADC_CH_IBAT_MIN_V	(-60)	/* mV range measured by ADC for ibat */
> +#define ADC_CH_IBAT_MAX_V	60
> +#define IBAT_VDROP_L		(-56)  /* mV */
> +#define IBAT_VDROP_H		56
> +
> +/* This is used to not lose precision when dividing to get gain and offset */
> +#define CALIB_SCALE		1000
> +/*
> + * Number of bits shift used to not lose precision
> + * when dividing to get ibat gain.
> + */
> +#define CALIB_SHIFT_IBAT	20
> +
> +/* Time in ms before disabling regulator */
> +#define GPADC_AUDOSUSPEND_DELAY		1
> +
> +#define CONVERSION_TIME			500 /* ms */
> +
> +enum ab8500_cal_channels {
> +	AB8500_CAL_VMAIN = 0,
> +	AB8500_CAL_BTEMP,
> +	AB8500_CAL_VBAT,
> +	AB8500_CAL_IBAT,
> +	AB8500_CAL_NR,
> +};
> +
> +/**
> + * struct ab8500_adc_cal_data - Table for storing gain and offset for the
> + * calibrated ADC channels
> + * @gain: Gain of the ADC channel
> + * @offset: Offset of the ADC channel
> + * @otp_calib_hi: Calibration from OTP
> + * @otp_calib_lo: Calibration from OTP
> + */
> +struct ab8500_adc_cal_data {
> +	s64 gain;
> +	s64 offset;
> +	u16 otp_calib_hi;
> +	u16 otp_calib_lo;
> +};
> +
> +/**
> + * struct ab8500_gpadc_chan_info - per-channel GPADC info
> + * @name: name of the channel
> + * @id: the internal AB8500 ID number for the channel
> + * @hardware_control: indicate that we want to use hardware ADC control
> + * on this channel, the default is software ADC control. Hardware control
> + * is normally only used to test the battery voltage during GSM bursts
> + * and needs a hardware trigger on the GPADCTrig pin of the ASIC.
> + * @falling_edge: indicate that we want to trigger on falling edge
> + * rather than rising edge, rising edge is the default
> + * @avg_sample: how many samples to average: must be 1, 4, 8 or 16.
> + * @trig_timer: how long to wait for the trigger, in 32kHz periods:
> + * 0 .. 255 periods
> + */
> +struct ab8500_gpadc_chan_info {
> +	const char *name;
> +	u8 id;
> +	bool hardware_control;
> +	bool falling_edge;
> +	u8 avg_sample;
> +	u8 trig_timer;
> +};
> +
> +/**
> + * struct ab8500_gpadc - AB8500 GPADC device information
> + * @dev: pointer to the containing device
> + * @ab8500: pointer to the parent AB8500 device
> + * @chans: internal per-channel information container
> + * @nchans: number of channels
> + * @complete: pointer to the completion that indicates
> + * the completion of an gpadc conversion cycle
> + * @vddadc: pointer to the regulator supplying VDDADC
> + * @irq_sw: interrupt number that is used by gpadc for software ADC conversion
> + * @irq_hw: interrupt number that is used by gpadc for hardware ADC conversion
> + * @cal_data: array of ADC calibration data structs
> + */
> +struct ab8500_gpadc {
> +	struct device *dev;
> +	struct ab8500 *ab8500;
> +	struct ab8500_gpadc_chan_info *chans;
> +	unsigned int nchans;
> +	struct completion complete;
> +	struct regulator *vddadc;
> +	int irq_sw;
> +	int irq_hw;
> +	struct ab8500_adc_cal_data cal_data[AB8500_CAL_NR];
> +};
> +
> +static struct ab8500_gpadc_chan_info *
> +ab8500_gpadc_get_channel(struct ab8500_gpadc *gpadc, u8 chan)
> +{
> +	struct ab8500_gpadc_chan_info *ch;
> +	int i;
> +
> +	for (i = 0; i < gpadc->nchans; i++) {
> +		ch = &gpadc->chans[i];
> +		if (ch->id == chan)
> +			break;
> +	}
> +	if (i == gpadc->nchans)
> +		return NULL;
> +
> +	return ch;
> +}
> +
> +/**
> + * ab8500_gpadc_ad_to_voltage() - Convert a raw ADC value to a voltage

Kernel doc should be complete if you are going to do it...

> + */
> +static int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc,
> +				      enum ab8500_gpadc_channel ch,
> +				      int ad_value)
> +{
> +	int res;
> +
> +	switch (ch) {
> +	case AB8500_GPADC_CHAN_MAIN_CHARGER:
> +		/* No calibration data available: just interpolate */
> +		if (!gpadc->cal_data[AB8500_CAL_VMAIN].gain) {
> +			res = ADC_CH_CHG_V_MIN + (ADC_CH_CHG_V_MAX -
> +				ADC_CH_CHG_V_MIN) * ad_value /
> +				ADC_RESOLUTION;
> +			break;
> +		}
> +		/* Here we can use calibration */
> +		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_VMAIN].gain +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].offset) / CALIB_SCALE;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_BAT_CTRL:
> +	case AB8500_GPADC_CHAN_BAT_TEMP:
> +	case AB8500_GPADC_CHAN_ACC_DET_1:
> +	case AB8500_GPADC_CHAN_ADC_AUX_1:
> +	case AB8500_GPADC_CHAN_ADC_AUX_2:
> +	case AB8500_GPADC_CHAN_XTAL_TEMP:
> +		/* No calibration data available: just interpolate */
> +		if (!gpadc->cal_data[AB8500_CAL_BTEMP].gain) {
> +			res = ADC_CH_BTEMP_MIN + (ADC_CH_BTEMP_MAX -
> +				ADC_CH_BTEMP_MIN) * ad_value /
> +				ADC_RESOLUTION;
> +			break;
> +		}
> +		/* Here we can use calibration */
> +		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_BTEMP].gain +
> +			gpadc->cal_data[AB8500_CAL_BTEMP].offset) / CALIB_SCALE;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_VBAT_A:
> +	case AB8500_GPADC_CHAN_VBAT_TRUE_MEAS:
> +		/* No calibration data available: just interpolate */
> +		if (!gpadc->cal_data[AB8500_CAL_VBAT].gain) {
> +			res = ADC_CH_VBAT_MIN + (ADC_CH_VBAT_MAX -
> +				ADC_CH_VBAT_MIN) * ad_value /
> +				ADC_RESOLUTION;
> +			break;
> +		}
> +		/* Here we can use calibration */
> +		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_VBAT].gain +
> +			gpadc->cal_data[AB8500_CAL_VBAT].offset) / CALIB_SCALE;
> +		break;
> +
> +	case AB8505_GPADC_CHAN_DIE_TEMP:
> +		res = ADC_CH_DIETEMP_MIN +
> +			(ADC_CH_DIETEMP_MAX - ADC_CH_DIETEMP_MIN) * ad_value /
> +			ADC_RESOLUTION;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_ACC_DET_2:
> +		res = ADC_CH_ACCDET2_MIN +
> +			(ADC_CH_ACCDET2_MAX - ADC_CH_ACCDET2_MIN) * ad_value /
> +			ADC_RESOLUTION;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_VBUS:
> +		res = ADC_CH_CHG_V_MIN +
> +			(ADC_CH_CHG_V_MAX - ADC_CH_CHG_V_MIN) * ad_value /
> +			ADC_RESOLUTION;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT:
> +	case AB8500_GPADC_CHAN_USB_CHARGER_CURRENT:
> +		res = ADC_CH_CHG_I_MIN +
> +			(ADC_CH_CHG_I_MAX - ADC_CH_CHG_I_MIN) * ad_value /
> +			ADC_RESOLUTION;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_BACKUP_BAT:
> +		res = ADC_CH_BKBAT_MIN +
> +			(ADC_CH_BKBAT_MAX - ADC_CH_BKBAT_MIN) * ad_value /
> +			ADC_RESOLUTION;
> +		break;
> +
> +	case AB8500_GPADC_CHAN_IBAT_VIRTUAL:
> +		/* No calibration data available: just interpolate */
> +		if (!gpadc->cal_data[AB8500_CAL_IBAT].gain) {
> +			res = ADC_CH_IBAT_MIN + (ADC_CH_IBAT_MAX -
> +				ADC_CH_IBAT_MIN) * ad_value /
> +				ADC_RESOLUTION;
> +			break;
> +		}
> +		/* Here we can use calibration */
> +		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_IBAT].gain +
> +				gpadc->cal_data[AB8500_CAL_IBAT].offset)
> +				>> CALIB_SHIFT_IBAT;
> +		break;
> +
> +	default:
> +		dev_err(gpadc->dev,
> +			"unknown channel ID: %d, not possible to convert\n",
> +			ch);
> +		res = -EINVAL;
> +		break;
> +
> +	}
> +
> +	return res;
> +}
> +
> +static int ab8500_gpadc_read(struct ab8500_gpadc *gpadc,
> +			     const struct ab8500_gpadc_chan_info *ch,
> +			     int *ibat)
> +{
> +	int ret;
> +	int looplimit = 0;
> +	unsigned long completion_timeout;
> +	u8 val;
> +	u8 low_data, high_data, low_data2, high_data2;
> +	u8 ctrl1;
> +	u8 ctrl23;
> +	unsigned int delay_min = 0;
> +	unsigned int delay_max = 0;
> +	u8 data_low_addr, data_high_addr;
> +
> +	if (!gpadc)
> +		return -ENODEV;
> +
> +	/* check if conversion is supported */
> +	if ((gpadc->irq_sw <= 0) && !ch->hardware_control)
> +		return -ENOTSUPP;
> +	if ((gpadc->irq_hw <= 0) && ch->hardware_control)
> +		return -ENOTSUPP;
> +
> +	/* Enable vddadc by grabbing PM runtime */
> +	pm_runtime_get_sync(gpadc->dev);
> +
> +	/* Check if ADC is not busy, lock and proceed */
> +	do {
> +		ret = abx500_get_register_interruptible(gpadc->dev,
> +			AB8500_GPADC, AB8500_GPADC_STAT_REG, &val);
> +		if (ret < 0)
> +			goto out;
> +		if (!(val & AB8500_GPADC_STAT_BUSY))
> +			break;
> +		msleep(20);
> +	} while (++looplimit < 10);
> +	if (looplimit >= 10 && (val & AB8500_GPADC_STAT_BUSY)) {
> +		dev_err(gpadc->dev, "gpadc_conversion: GPADC busy");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	/* Enable GPADC */
> +	ctrl1 = AB8500_GPADC_CTRL1_ENABLE;
> +
> +	/* Select the channel source and set average samples */
> +	switch (ch->avg_sample) {
> +	case 1:
> +		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_1;
> +		break;
> +	case 4:
> +		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_4;
> +		break;
> +	case 8:
> +		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_8;
> +		break;
> +	default:
> +		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_16;
> +		break;
> +	}
> +
> +	if (ch->hardware_control) {
> +		ret = abx500_set_register_interruptible(gpadc->dev,
> +				AB8500_GPADC, AB8500_GPADC_CTRL3_REG, ctrl23);
> +		ctrl1 |= AB8500_GPADC_CTRL1_TRIG_ENA;
> +		if (ch->falling_edge)
> +			ctrl1 |= AB8500_GPADC_CTRL1_TRIG_EDGE;
> +	} else {
> +		ret = abx500_set_register_interruptible(gpadc->dev,
> +				AB8500_GPADC, AB8500_GPADC_CTRL2_REG, ctrl23);
> +	}
> +	if (ret < 0) {
> +		dev_err(gpadc->dev,
> +			"gpadc_conversion: set avg samples failed\n");
> +		goto out;
> +	}
> +
> +	/*
> +	 * Enable ADC, buffering, select rising edge and enable ADC path
> +	 * charging current sense if it needed, ABB 3.0 needs some special
> +	 * treatment too.
> +	 */
> +	switch (ch->id) {
> +	case AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT:
> +	case AB8500_GPADC_CHAN_USB_CHARGER_CURRENT:
> +		ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA |
> +			AB8500_GPADC_CTRL1_ICHAR_ENA;
> +		break;
> +	case AB8500_GPADC_CHAN_BAT_TEMP:
> +		if (!is_ab8500_2p0_or_earlier(gpadc->ab8500)) {
> +			ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA |
> +				AB8500_GPADC_CTRL1_BTEMP_PULL_UP;
> +			/*
> +			 * Delay might be needed for ABB8500 cut 3.0, if not,
> +			 * remove when hardware will be available
> +			 */
> +			delay_min = 1000; /* Delay in micro seconds */
> +			delay_max = 10000; /* large range optimises sleepmode */
> +			break;
> +		}
> +		/* Fall through */
> +	default:
> +		ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA;
> +		break;
> +	}
> +
> +	/* Write configuration to control register 1 */
> +	ret = abx500_set_register_interruptible(gpadc->dev,
> +		AB8500_GPADC, AB8500_GPADC_CTRL1_REG, ctrl1);
> +	if (ret < 0) {
> +		dev_err(gpadc->dev,
> +			"gpadc_conversion: set Control register failed\n");
> +		goto out;
> +	}
> +
> +	if (delay_min != 0)
> +		usleep_range(delay_min, delay_max);
> +
> +	if (ch->hardware_control) {
> +		/* Set trigger delay timer */
> +		ret = abx500_set_register_interruptible(gpadc->dev,
> +			AB8500_GPADC, AB8500_GPADC_AUTO_TIMER_REG,
> +			ch->trig_timer);
> +		if (ret < 0) {
> +			dev_err(gpadc->dev,
> +				"gpadc_conversion: trig timer failed\n");
> +			goto out;
> +		}
> +		completion_timeout = 2 * HZ;
> +		data_low_addr = AB8500_GPADC_AUTODATAL_REG;
> +		data_high_addr = AB8500_GPADC_AUTODATAH_REG;
> +	} else {
> +		/* Start SW conversion */
> +		ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
> +			AB8500_GPADC, AB8500_GPADC_CTRL1_REG,
> +			AB8500_GPADC_CTRL1_START_SW_CONV,
> +			AB8500_GPADC_CTRL1_START_SW_CONV);
> +		if (ret < 0) {
> +			dev_err(gpadc->dev,
> +				"gpadc_conversion: start s/w conv failed\n");
> +			goto out;
> +		}
> +		completion_timeout = msecs_to_jiffies(CONVERSION_TIME);
> +		data_low_addr = AB8500_GPADC_MANDATAL_REG;
> +		data_high_addr = AB8500_GPADC_MANDATAH_REG;
> +	}
> +
> +	/* Wait for completion of conversion */
> +	if (!wait_for_completion_timeout(&gpadc->complete,
> +			completion_timeout)) {
> +		dev_err(gpadc->dev,
> +			"timeout didn't receive GPADC conv interrupt\n");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	/* Read the converted RAW data */
> +	ret = abx500_get_register_interruptible(gpadc->dev,
> +			AB8500_GPADC, data_low_addr, &low_data);
> +	if (ret < 0) {
> +		dev_err(gpadc->dev,
> +			"gpadc_conversion: read low data failed\n");
> +		goto out;
> +	}
> +
> +	ret = abx500_get_register_interruptible(gpadc->dev,
> +		AB8500_GPADC, data_high_addr, &high_data);
> +	if (ret < 0) {
> +		dev_err(gpadc->dev,
> +			"gpadc_conversion: read high data failed\n");
> +		goto out;
> +	}
> +
> +	/* Check if double conversion is required */
> +	if ((ch->id == AB8500_GPADC_CHAN_BAT_CTRL_AND_IBAT) ||
> +	    (ch->id == AB8500_GPADC_CHAN_VBAT_MEAS_AND_IBAT) ||
> +	    (ch->id == AB8500_GPADC_CHAN_VBAT_TRUE_MEAS_AND_IBAT) ||
> +	    (ch->id == AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT)) {
> +
> +		if (ch->hardware_control) {
> +			/* not supported */
> +			ret = -ENOTSUPP;
> +			dev_err(gpadc->dev,
> +				"gpadc_conversion: only SW double conversion supported\n");
> +			goto out;
> +		} else {
> +			/* Read the converted RAW data 2 */
> +			ret = abx500_get_register_interruptible(gpadc->dev,
> +				AB8500_GPADC, AB8540_GPADC_MANDATA2L_REG,
> +				&low_data2);
> +			if (ret < 0) {
> +				dev_err(gpadc->dev,
> +					"gpadc_conversion: read sw low data 2 failed\n");
> +				goto out;
> +			}
> +
> +			ret = abx500_get_register_interruptible(gpadc->dev,
> +				AB8500_GPADC, AB8540_GPADC_MANDATA2H_REG,
> +				&high_data2);
> +			if (ret < 0) {
> +				dev_err(gpadc->dev,
> +					"gpadc_conversion: read sw high data 2 failed\n");
> +				goto out;
> +			}
> +			if (ibat != NULL) {
> +				*ibat = (high_data2 << 8) | low_data2;
> +			} else {
> +				dev_warn(gpadc->dev,
> +					"gpadc_conversion: ibat not stored\n");
> +			}
> +
> +		}
> +	}
> +
> +	/* Disable GPADC */
> +	ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
> +		AB8500_GPADC_CTRL1_REG, AB8500_GPADC_CTRL1_DISABLE);
> +	if (ret < 0) {
> +		dev_err(gpadc->dev, "gpadc_conversion: disable gpadc failed\n");
> +		goto out;
> +	}
> +
> +	/* This eventually drops the regulator */
> +	pm_runtime_mark_last_busy(gpadc->dev);
> +	pm_runtime_put_autosuspend(gpadc->dev);
> +
> +	return (high_data << 8) | low_data;
> +
> +out:
> +	/*
> +	 * It has shown to be needed to turn off the GPADC if an error occurs,
> +	 * otherwise we might have problem when waiting for the busy bit in the
> +	 * GPADC status register to go low. In V1.1 there wait_for_completion
> +	 * seems to timeout when waiting for an interrupt.. Not seen in V2.0
> +	 */
> +	(void) abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
> +		AB8500_GPADC_CTRL1_REG, AB8500_GPADC_CTRL1_DISABLE);
> +	pm_runtime_put(gpadc->dev);
> +	dev_err(gpadc->dev,
> +		"gpadc_conversion: Failed to AD convert channel %d\n", ch->id);
> +
> +	return ret;
> +}
> +
> +/**
> + * ab8500_bm_gpadcconvend_handler() - isr for gpadc conversion completion
> + * @irq: irq number
> + * @data: pointer to the data passed during request irq
> + *
> + * This is a interrupt service routine for gpadc conversion completion.
> + * Notifies the gpadc completion is completed and the converted raw value
> + * can be read from the registers.
> + * Returns IRQ status(IRQ_HANDLED)
> + */
> +static irqreturn_t ab8500_bm_gpadcconvend_handler(int irq, void *data)
> +{
> +	struct ab8500_gpadc *gpadc = data;
> +
> +	complete(&gpadc->complete);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int otp_cal_regs[] = {
> +	AB8500_GPADC_CAL_1,
> +	AB8500_GPADC_CAL_2,
> +	AB8500_GPADC_CAL_3,
> +	AB8500_GPADC_CAL_4,
> +	AB8500_GPADC_CAL_5,
> +	AB8500_GPADC_CAL_6,
> +	AB8500_GPADC_CAL_7,
> +};
> +
> +static int otp4_cal_regs[] = {
> +	AB8540_GPADC_OTP4_REG_7,
> +	AB8540_GPADC_OTP4_REG_6,
> +	AB8540_GPADC_OTP4_REG_5,
> +};
> +
> +static void ab8500_gpadc_read_calibration_data(struct ab8500_gpadc *gpadc)
> +{
> +	int i;
> +	int ret[ARRAY_SIZE(otp_cal_regs)];
> +	u8 gpadc_cal[ARRAY_SIZE(otp_cal_regs)];
> +	int ret_otp4[ARRAY_SIZE(otp4_cal_regs)];
> +	u8 gpadc_otp4[ARRAY_SIZE(otp4_cal_regs)];
> +	int vmain_high, vmain_low;
> +	int btemp_high, btemp_low;
> +	int vbat_high, vbat_low;
> +	int ibat_high, ibat_low;
> +	s64 V_gain, V_offset, V2A_gain, V2A_offset;
> +
> +	/* First we read all OTP registers and store the error code */
> +	for (i = 0; i < ARRAY_SIZE(otp_cal_regs); i++) {
> +		ret[i] = abx500_get_register_interruptible(gpadc->dev,
> +			AB8500_OTP_EMUL, otp_cal_regs[i],  &gpadc_cal[i]);
> +		if (ret[i] < 0) {
> +			/* Continue anyway: maybe the other registers are OK */
> +			dev_err(gpadc->dev, "%s: read otp reg 0x%02x failed\n",
> +				__func__, otp_cal_regs[i]);
> +		} else {
> +			/* Put this in the entropy pool as device-unique */
> +			add_device_randomness(&ret[i], sizeof(ret[i]));
> +		}
> +	}
> +
> +	/*
> +	 * The ADC calibration data is stored in OTP registers.
> +	 * The layout of the calibration data is outlined below and a more
> +	 * detailed description can be found in UM0836
> +	 *
> +	 * vm_h/l = vmain_high/low
> +	 * bt_h/l = btemp_high/low
> +	 * vb_h/l = vbat_high/low
> +	 *
> +	 * Data bits 8500/9540:
> +	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * |						   | vm_h9 | vm_h8
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * |		   | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 *
> +	 * Data bits 8540:
> +	 * OTP2
> +	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * |
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vm_h9 | vm_h8 | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 *
> +	 * Data bits 8540:
> +	 * OTP4
> +	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * |					   | ib_h9 | ib_h8 | ib_h7
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | ib_h6 | ib_h5 | ib_h4 | ib_h3 | ib_h2 | ib_h1 | ib_h0 | ib_l5
> +	 * |.......|.......|.......|.......|.......|.......|.......|.......
> +	 * | ib_l4 | ib_l3 | ib_l2 | ib_l1 | ib_l0 |
> +	 *
> +	 *
> +	 * Ideal output ADC codes corresponding to injected input voltages
> +	 * during manufacturing is:
> +	 *
> +	 * vmain_high: Vin = 19500mV / ADC ideal code = 997
> +	 * vmain_low:  Vin = 315mV   / ADC ideal code = 16
> +	 * btemp_high: Vin = 1300mV  / ADC ideal code = 985
> +	 * btemp_low:  Vin = 21mV    / ADC ideal code = 16
> +	 * vbat_high:  Vin = 4700mV  / ADC ideal code = 982
> +	 * vbat_low:   Vin = 2380mV  / ADC ideal code = 33
> +	 */
> +
> +	if (is_ab8540(gpadc->ab8500)) {
> +		/* Calculate gain and offset for VMAIN if all reads succeeded*/
> +		if (!(ret[1] < 0 || ret[2] < 0)) {
> +			vmain_high = (((gpadc_cal[1] & 0xFF) << 2) |
> +				((gpadc_cal[2] & 0xC0) >> 6));
> +			vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);
> +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_hi =
> +				(u16)vmain_high;
> +			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_lo =
> +				(u16)vmain_low;
> +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].gain = CALIB_SCALE *
> +				(19500 - 315) / (vmain_high - vmain_low);
> +			gpadc->cal_data[AB8500_CAL_VMAIN].offset = CALIB_SCALE *
> +				19500 - (CALIB_SCALE * (19500 - 315) /
> +				(vmain_high - vmain_low)) * vmain_high;
> +		} else {
> +			gpadc->cal_data[AB8500_CAL_VMAIN].gain = 0;
> +		}
> +
> +		/* Read IBAT calibration Data */
> +		for (i = 0; i < ARRAY_SIZE(otp4_cal_regs); i++) {
> +			ret_otp4[i] = abx500_get_register_interruptible(
> +					gpadc->dev, AB8500_OTP_EMUL,
> +					otp4_cal_regs[i],  &gpadc_otp4[i]);
> +			if (ret_otp4[i] < 0)
> +				dev_err(gpadc->dev,
> +					"%s: read otp4 reg 0x%02x failed\n",
> +					__func__, otp4_cal_regs[i]);
> +		}
> +
> +		/* Calculate gain and offset for IBAT if all reads succeeded */
> +		if (!(ret_otp4[0] < 0 || ret_otp4[1] < 0 || ret_otp4[2] < 0)) {
> +			ibat_high = (((gpadc_otp4[0] & 0x07) << 7) |
> +				((gpadc_otp4[1] & 0xFE) >> 1));
> +			ibat_low = (((gpadc_otp4[1] & 0x01) << 5) |
> +				((gpadc_otp4[2] & 0xF8) >> 3));
> +
> +			gpadc->cal_data[AB8500_CAL_IBAT].otp_calib_hi =
> +				(u16)ibat_high;
> +			gpadc->cal_data[AB8500_CAL_IBAT].otp_calib_lo =
> +				(u16)ibat_low;
> +
> +			V_gain = ((IBAT_VDROP_H - IBAT_VDROP_L)
> +				<< CALIB_SHIFT_IBAT) / (ibat_high - ibat_low);
> +
> +			V_offset = (IBAT_VDROP_H << CALIB_SHIFT_IBAT) -
> +				(((IBAT_VDROP_H - IBAT_VDROP_L) <<
> +				CALIB_SHIFT_IBAT) / (ibat_high - ibat_low))
> +				* ibat_high;
> +			/*
> +			 * Result obtained is in mV (at a scale factor),
> +			 * we need to calculate gain and offset to get mA
> +			 */
> +			V2A_gain = (ADC_CH_IBAT_MAX - ADC_CH_IBAT_MIN)/
> +				(ADC_CH_IBAT_MAX_V - ADC_CH_IBAT_MIN_V);
> +			V2A_offset = ((ADC_CH_IBAT_MAX_V * ADC_CH_IBAT_MIN -
> +				ADC_CH_IBAT_MAX * ADC_CH_IBAT_MIN_V)
> +				<< CALIB_SHIFT_IBAT)
> +				/ (ADC_CH_IBAT_MAX_V - ADC_CH_IBAT_MIN_V);
> +
> +			gpadc->cal_data[AB8500_CAL_IBAT].gain =
> +				V_gain * V2A_gain;
> +			gpadc->cal_data[AB8500_CAL_IBAT].offset =
> +				V_offset * V2A_gain + V2A_offset;
> +		} else {
> +			gpadc->cal_data[AB8500_CAL_IBAT].gain = 0;
> +		}
> +
> +		dev_dbg(gpadc->dev, "IBAT gain %llu offset %llu\n",
> +			gpadc->cal_data[AB8500_CAL_IBAT].gain,
> +			gpadc->cal_data[AB8500_CAL_IBAT].offset);
> +	} else {
> +		/* Calculate gain and offset for VMAIN if all reads succeeded */
> +		if (!(ret[0] < 0 || ret[1] < 0 || ret[2] < 0)) {
> +			vmain_high = (((gpadc_cal[0] & 0x03) << 8) |
> +				((gpadc_cal[1] & 0x3F) << 2) |
> +				((gpadc_cal[2] & 0xC0) >> 6));
> +			vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);
> +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_hi =
> +				(u16)vmain_high;
> +			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_lo =
> +				(u16)vmain_low;
> +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].gain = CALIB_SCALE *
> +				(19500 - 315) / (vmain_high - vmain_low);
> +
> +			gpadc->cal_data[AB8500_CAL_VMAIN].offset = CALIB_SCALE *
> +				19500 - (CALIB_SCALE * (19500 - 315) /
> +				(vmain_high - vmain_low)) * vmain_high;
> +		} else {
> +			gpadc->cal_data[AB8500_CAL_VMAIN].gain = 0;
> +		}
> +	}
> +
> +	/* Calculate gain and offset for BTEMP if all reads succeeded */
> +	if (!(ret[2] < 0 || ret[3] < 0 || ret[4] < 0)) {
> +		btemp_high = (((gpadc_cal[2] & 0x01) << 9) |
> +			(gpadc_cal[3] << 1) | ((gpadc_cal[4] & 0x80) >> 7));
> +		btemp_low = ((gpadc_cal[4] & 0x7C) >> 2);
> +
> +		gpadc->cal_data[AB8500_CAL_BTEMP].otp_calib_hi = (u16)btemp_high;
> +		gpadc->cal_data[AB8500_CAL_BTEMP].otp_calib_lo = (u16)btemp_low;
> +
> +		gpadc->cal_data[AB8500_CAL_BTEMP].gain =
> +			CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low);
> +		gpadc->cal_data[AB8500_CAL_BTEMP].offset = CALIB_SCALE * 1300 -
> +			(CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low))
> +			* btemp_high;
> +	} else {
> +		gpadc->cal_data[AB8500_CAL_BTEMP].gain = 0;
> +	}
> +
> +	/* Calculate gain and offset for VBAT if all reads succeeded */
> +	if (!(ret[4] < 0 || ret[5] < 0 || ret[6] < 0)) {
> +		vbat_high = (((gpadc_cal[4] & 0x03) << 8) | gpadc_cal[5]);
> +		vbat_low = ((gpadc_cal[6] & 0xFC) >> 2);
> +
> +		gpadc->cal_data[AB8500_CAL_VBAT].otp_calib_hi = (u16)vbat_high;
> +		gpadc->cal_data[AB8500_CAL_VBAT].otp_calib_lo = (u16)vbat_low;
> +
> +		gpadc->cal_data[AB8500_CAL_VBAT].gain = CALIB_SCALE *
> +			(4700 - 2380) /	(vbat_high - vbat_low);
> +		gpadc->cal_data[AB8500_CAL_VBAT].offset = CALIB_SCALE * 4700 -
> +			(CALIB_SCALE * (4700 - 2380) /
> +			(vbat_high - vbat_low)) * vbat_high;
> +	} else {
> +		gpadc->cal_data[AB8500_CAL_VBAT].gain = 0;
> +	}
> +
> +	dev_dbg(gpadc->dev, "VMAIN gain %llu offset %llu\n",
> +		gpadc->cal_data[AB8500_CAL_VMAIN].gain,
> +		gpadc->cal_data[AB8500_CAL_VMAIN].offset);
> +
> +	dev_dbg(gpadc->dev, "BTEMP gain %llu offset %llu\n",
> +		gpadc->cal_data[AB8500_CAL_BTEMP].gain,
> +		gpadc->cal_data[AB8500_CAL_BTEMP].offset);
> +
> +	dev_dbg(gpadc->dev, "VBAT gain %llu offset %llu\n",
> +		gpadc->cal_data[AB8500_CAL_VBAT].gain,
> +		gpadc->cal_data[AB8500_CAL_VBAT].offset);
> +}
> +
> +static int ab8500_gpadc_read_raw(struct iio_dev *indio_dev,
> +				 struct iio_chan_spec const *chan,
> +				 int *val, int *val2, long mask)
> +{
> +	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
> +	const struct ab8500_gpadc_chan_info *ch;
> +	int raw_val;
> +	int processed;
> +
> +	ch = ab8500_gpadc_get_channel(gpadc, chan->address);
> +	if (!ch) {
> +		dev_err(gpadc->dev, "no such channel %lu\n",
> +			chan->address);
> +		return -EINVAL;
> +	}
> +
> +	dev_dbg(gpadc->dev, "read channel %d\n", ch->id);

I'd suggest dropping these left over bits of debug.
Easy enough to get the same info via other means (ftrace etc)

> +
> +	raw_val = ab8500_gpadc_read(gpadc, ch, NULL);
> +	if (raw_val < 0)
> +		return raw_val;
> +
> +	if (mask == IIO_CHAN_INFO_RAW) {
> +		*val = raw_val;
> +		return IIO_VAL_INT;
> +	}
> +
> +	if (mask == IIO_CHAN_INFO_PROCESSED) {
> +		processed = ab8500_gpadc_ad_to_voltage(gpadc, ch->id, raw_val);
> +		if (processed < 0)
> +			return processed;
> +
> +		/* Return millivolt or milliamps or millicentigrades */
> +		*val = processed * 1000;
> +		return IIO_VAL_INT;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ab8500_gpadc_of_xlate(struct iio_dev *indio_dev,
> +				 const struct of_phandle_args *iiospec)
> +{
> +	int i;
> +
> +	for (i = 0; i < indio_dev->num_channels; i++)
> +		if (indio_dev->channels[i].channel == iiospec->args[0])
> +			return i;
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info ab8500_gpadc_info = {
> +	.of_xlate = ab8500_gpadc_of_xlate,
> +	.read_raw = ab8500_gpadc_read_raw,
> +};
> +
> +#ifdef CONFIG_PM
> +static int ab8500_gpadc_runtime_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
> +
> +	regulator_disable(gpadc->vddadc);
> +
> +	return 0;
> +}
> +
> +static int ab8500_gpadc_runtime_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = regulator_enable(gpadc->vddadc);
> +	if (ret)
> +		dev_err(dev, "Failed to enable vddadc: %d\n", ret);
> +
> +	return ret;
> +}
> +#endif
> +
> +/**
> + * ab8500_gpadc_parse_channel() - process devicetree channel configuration
> + * @dev: pointer to containing device
> + * @np: device tree node for the channel to configure
> + * @ch: channel info to fill in
> + * @iio_chan: IIO channel specification to fill in
> + *
> + * The devicetree will set up the channel for use with the specific device,
> + * and define usage for things like AUX GPADC inputs more precisely.
> + */
> +static int ab8500_gpadc_parse_channel(struct device *dev,
> +				      struct device_node *np,
> +				      struct ab8500_gpadc_chan_info *ch,
> +				      struct iio_chan_spec *iio_chan)
> +{
> +	const char *name = np->name;
> +	u32 chan;
> +	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 > AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT) {
> +		dev_err(dev, "%s channel number out of range %d\n", name, chan);
> +		return -EINVAL;
> +	}
> +
> +	iio_chan->channel = chan;
> +	iio_chan->datasheet_name = name;
> +	iio_chan->indexed = 1;
> +	iio_chan->address = chan;
> +	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +		BIT(IIO_CHAN_INFO_PROCESSED);
> +	/* Most are voltages (also temperatures), some are currents */
> +	if ((chan == AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT) ||
> +	    (chan == AB8500_GPADC_CHAN_USB_CHARGER_CURRENT))
> +		iio_chan->type = IIO_CURRENT;
> +	else
> +		iio_chan->type = IIO_VOLTAGE;
> +
> +	ch->id = chan;
> +
> +	/* Sensible defaults */
> +	ch->avg_sample = 16;
> +	ch->hardware_control = false;
> +	ch->falling_edge = false;
> +	ch->trig_timer = 0;
> +
> +	return 0;
> +}
> +
> +/**
> + * ab8500_gpadc_parse_channels() - Parse the GPADC channels from DT
> + * @gpadc: the GPADC to configure the channels for
> + * @np: device tree node containing the channel configurations
> + * @chans: the IIO channels we parsed
> + * @nchans: the number of IIO channels we parsed
> + */
> +static int ab8500_gpadc_parse_channels(struct ab8500_gpadc *gpadc,
> +				       struct device_node *np,
> +				       struct iio_chan_spec **chans_parsed,
> +				       unsigned int *nchans_parsed)
> +{
> +	struct device_node *child;
> +	struct ab8500_gpadc_chan_info *ch;
> +	struct iio_chan_spec *iio_chans;
> +	unsigned int nchans;
> +	int i;
> +
> +	nchans = of_get_available_child_count(np);
> +	if (!nchans) {
> +		dev_err(gpadc->dev, "no channel children\n");
> +		return -ENODEV;
> +	}
> +	dev_info(gpadc->dev, "found %d ADC channels\n", nchans);
> +
> +	iio_chans = devm_kcalloc(gpadc->dev, nchans,
> +				 sizeof(*iio_chans), GFP_KERNEL);
> +	if (!iio_chans)
> +		return -ENOMEM;
> +
> +	gpadc->chans = devm_kcalloc(gpadc->dev, nchans,
> +				    sizeof(*gpadc->chans), GFP_KERNEL);
> +	if (!gpadc->chans)
> +		return -ENOMEM;
> +
> +	i = 0;
> +	for_each_available_child_of_node(np, child) {
> +		struct iio_chan_spec *iio_chan;
> +		int ret;
> +
> +		ch = &gpadc->chans[i];
> +		iio_chan = &iio_chans[i];
> +
> +		ret = ab8500_gpadc_parse_channel(gpadc->dev, child, ch,
> +						 iio_chan);
> +		if (ret) {
> +			of_node_put(child);
> +			return ret;
> +		}
> +		i++;
> +	}
> +	gpadc->nchans = nchans;
> +	*chans_parsed = iio_chans;
> +	*nchans_parsed = nchans;
> +
> +	return 0;
> +}
> +
> +static int ab8500_gpadc_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;

Looks like this is set below in all paths that use it.

> +	struct ab8500_gpadc *gpadc;
> +	struct iio_dev *indio_dev;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = pdev->dev.of_node;
> +	struct iio_chan_spec *iio_chans;
> +	unsigned int n_iio_chans;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*gpadc));
> +	if (!indio_dev)
> +		return -ENOMEM;

nitpick: Blank line here.

> +	platform_set_drvdata(pdev, indio_dev);
> +	gpadc = iio_priv(indio_dev);
> +
> +	gpadc->dev = dev;
> +	gpadc->ab8500 = dev_get_drvdata(dev->parent);
> +
> +	ret = ab8500_gpadc_parse_channels(gpadc, np, &iio_chans, &n_iio_chans);
> +	if (ret)
> +		return ret;
> +
> +	gpadc->irq_sw = platform_get_irq_byname(pdev, "SW_CONV_END");
> +	if (gpadc->irq_sw < 0) {
> +		dev_err(dev, "failed to get platform sw_conv_end irq\n");
> +		return gpadc->irq_sw;
> +	}
> +
> +	gpadc->irq_hw = platform_get_irq_byname(pdev, "HW_CONV_END");
> +	if (gpadc->irq_hw < 0) {
> +		dev_err(dev, "failed to get platform hw_conv_end irq\n");
> +		return gpadc->irq_hw;
> +	}
> +
> +	/* Initialize completion used to notify completion of conversion */
> +	init_completion(&gpadc->complete);
> +
> +	/* Request interrupts */
> +	ret = devm_request_threaded_irq(dev,
> +		gpadc->irq_sw, NULL,
> +		ab8500_bm_gpadcconvend_handler,
> +		IRQF_NO_SUSPEND | IRQF_ONESHOT,
> +		"ab8500-gpadc-sw",
> +		gpadc);
> +	if (ret < 0) {
> +		dev_err(dev,
> +			"failed to request sw conversion irq %d\n",
> +			gpadc->irq_sw);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(dev,
> +		gpadc->irq_hw, NULL,
> +		                        ab8500_bm_gpadcconvend_handler,

Seems to be under 80 chars when aligned with the opening bracket,
so nice to do that where we can.

> +		IRQF_NO_SUSPEND | IRQF_ONESHOT,
> +		"ab8500-gpadc-hw",
> +		gpadc);
> +	if (ret < 0) {
> +		dev_err(dev,
> +			"Failed to request hw conversion irq: %d\n",
> +			gpadc->irq_hw);
> +		return ret;
> +	}
> +
> +	/* The VTVout LDO used to power the AB8500 GPADC */
> +	gpadc->vddadc = devm_regulator_get(dev, "vddadc");
> +	if (IS_ERR(gpadc->vddadc)) {
> +		ret = PTR_ERR(gpadc->vddadc);
> +		dev_err(dev, "failed to get vddadc\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(gpadc->vddadc);
> +	if (ret) {
> +		dev_err(dev, "failed to enable vddadc: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Enable runtime PM */
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_set_autosuspend_delay(dev, GPADC_AUDOSUSPEND_DELAY);
> +	pm_runtime_use_autosuspend(dev);
> +
> +	ab8500_gpadc_read_calibration_data(gpadc);
> +
> +	pm_runtime_put(dev);
> +
> +	indio_dev->dev.parent = dev;
> +	indio_dev->dev.of_node = np;
> +	indio_dev->name = "ab8500-gpadc";
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &ab8500_gpadc_info;
> +	indio_dev->channels = iio_chans;
> +	indio_dev->num_channels = n_iio_chans;
> +
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		goto out_dis_pm;
> +
> +	dev_info(dev, "AB8500 GPADC initialized\n");

I'm slightly against this sort of noise, but if you are particularly
attached to it will let it go.

> +
> +	return 0;
> +
> +out_dis_pm:
> +	pm_runtime_get_sync(dev);
> +	pm_runtime_put_noidle(dev);
> +	pm_runtime_disable(dev);
> +	regulator_disable(gpadc->vddadc);
> +
> +	return ret;
> +}
> +
> +static int ab8500_gpadc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
> +
> +	pm_runtime_get_sync(gpadc->dev);
> +	pm_runtime_put_noidle(gpadc->dev);
> +	pm_runtime_disable(gpadc->dev);
> +	regulator_disable(gpadc->vddadc);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ab8500_gpadc_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				pm_runtime_force_resume)
> +	SET_RUNTIME_PM_OPS(ab8500_gpadc_runtime_suspend,
> +			   ab8500_gpadc_runtime_resume,
> +			   NULL)
> +};
> +
> +static struct platform_driver ab8500_gpadc_driver = {
> +	.probe = ab8500_gpadc_probe,
> +	.remove = ab8500_gpadc_remove,
> +	.driver = {
> +		.name = "ab8500-gpadc",
> +		.pm = &ab8500_gpadc_pm_ops,
> +	},
> +};
> +builtin_platform_driver(ab8500_gpadc_driver);