Date: Wed, 25 Nov 2015 13:20:47 +0100 (CET)
From: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
To: Marc Titinger <mtitinger@baylibre.com>
cc: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] iio: ina2xx: add support for TI INA2xx Power
 Monitors
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References: <1448450896-24387-1-git-send-email-mtitinger@baylibre.com> <1448450896-24387-2-git-send-email-mtitinger@baylibre.com>
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> in SOFTWARE buffer mode, a kthread will capture the active scan_elements
> into a kfifo, then compute the remaining time until the next capture tick
> and do an active wait (udelay).

minor comments below 

> 
> Datasheet: http://www.ti.com/lit/gpn/ina226
> 
> Signed-off-by: Marc Titinger <mtitinger@baylibre.com>
> ---
>  drivers/iio/adc/Kconfig      |  10 +
>  drivers/iio/adc/Makefile     |   1 +
>  drivers/iio/adc/ina2xx-iio.c | 684 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 695 insertions(+)
>  create mode 100644 drivers/iio/adc/ina2xx-iio.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index eb0cd89..9b87372 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -170,6 +170,16 @@ config EXYNOS_ADC
>  	  of SoCs for drivers such as the touchscreen and hwmon to use to share
>  	  this resource.
>  
> +config INA2XX_IIO
> +	tristate "Texas Instruments INA2xx Power Monitors IIO driver"
> +	depends on I2C
> +	select REGMAP_I2C
> +	select IIO_BUFFER
> +	help
> +	  Say yes here to build support for TI INA2xx familly Power Monitors.

family

> +
> +	  Note that this is not the existing hwmon interface for this device.

this message not very clear

> +
>  config LP8788_ADC
>  	tristate "LP8788 ADC driver"
>  	depends on MFD_LP8788
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index a096210..74e4341 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
>  obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
>  obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
>  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> +obj-$(CONFIG_INA2XX_IIO) += ina2xx-iio.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>  obj-$(CONFIG_MAX1027) += max1027.o
>  obj-$(CONFIG_MAX1363) += max1363.o
> diff --git a/drivers/iio/adc/ina2xx-iio.c b/drivers/iio/adc/ina2xx-iio.c
> new file mode 100644
> index 0000000..4a0026c
> --- /dev/null
> +++ b/drivers/iio/adc/ina2xx-iio.c
> @@ -0,0 +1,684 @@
> +/*
> + * INA2XX Current and Power Monitors
> + *
> + * Copyright 2015 Baylibre SAS.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * Based on linux/drivers/iio/adc/ad7291.c
> + * Copyright 2010-2011 Analog Devices Inc.
> + *
> + * Based on linux/drivers/hwmon/ina2xx.c
> + * Copyright 2012 Lothar Felten <l-felten@ti.com>
> + *
> + * Licensed under the GPL-2 or later.
> + *
> + * IIO driver for INA219-220-226-230-231
> + *
> + * Configurable 7-bit I2C slave address from 0x40 to 0x4F
> + */
> +#include <linux/module.h>
> +#include <linux/kthread.h>
> +#include <linux/delay.h>
> +#include <linux/iio/kfifo_buf.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/platform_data/ina2xx.h>
> +
> +#include <linux/util_macros.h>
> +
> +/*
> + * INA2XX registers definition
> + */
> +/* common register definitions */

comment style; do we need both?

> +#define INA2XX_CONFIG                   0x00
> +#define INA2XX_SHUNT_VOLTAGE            0x01	/* readonly */
> +#define INA2XX_BUS_VOLTAGE              0x02	/* readonly */
> +#define INA2XX_POWER                    0x03	/* readonly */
> +#define INA2XX_CURRENT                  0x04	/* readonly */
> +#define INA2XX_CALIBRATION              0x05
> +
> +#define INA226_ALERT_MASK		0x06
> +#define INA266_CVRF			BIT(3)
> +
> +/* register count */
> +#define INA219_REGISTERS                6
> +#define INA226_REGISTERS                8
> +#define INA2XX_MAX_REGISTERS            8
> +
> +/* settings - depend on use case */
> +#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=8 */
> +#define INA226_CONFIG_DEFAULT           0x4327
> +#define INA226_DEFAULT_AVG              4
> +#define INA226_DEFAULT_IT		1110
> +
> +#define INA2XX_RSHUNT_DEFAULT           10000
> +
> +/*
> + * bit mask for reading the averaging setting in the configuration register
> + * FIXME: use regmap_fields.
> + */
> +#define INA2XX_MODE_MASK	GENMASK(3, 0)
> +
> +#define INA226_AVG_MASK		GENMASK(11, 9)
> +#define INA226_SHIFT_AVG(val)	((val) << 9)
> +
> +/* Integration time for VBus */
> +#define INA226_ITB_MASK		GENMASK(8, 6)
> +#define INA226_SHIFT_ITB(val)	((val) << 6)
> +
> +/*Integration Time for VShunt */

time

> +#define INA226_ITS_MASK		GENMASK(5, 3)
> +#define INA226_SHIFT_ITS(val)	((val) << 3)
> +
> +
> +static bool ina2xx_is_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	return (reg == INA2XX_CONFIG) || (reg > INA2XX_CURRENT);
> +}
> +
> +static bool ina2xx_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	return (reg != INA2XX_CONFIG);
> +}
> +
> +static struct regmap_config ina2xx_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 16,
> +
> +	.writeable_reg = ina2xx_is_writeable_reg,
> +	.volatile_reg = ina2xx_is_volatile_reg,
> +};
> +
> +enum ina2xx_ids { ina219, ina226 };
> +
> +struct ina2xx_config {
> +	u16 config_default;
> +	int calibration_factor;
> +	int registers;
> +	int shunt_div;
> +	int bus_voltage_shift;
> +	int bus_voltage_lsb;	/* uV */
> +	int power_lsb;		/* uW */
> +};
> +
> +struct ina2xx_chip_info {
> +	struct regmap *regmap;
> +	struct task_struct *task;
> +	const struct ina2xx_config *config;
> +	struct mutex state_lock;
> +	long rshunt;
> +	int avg;
> +	int itb; /* Bus voltage integration time uS */
> +	int its; /* Shunt voltage integration tim uS */

time

> +};
> +
> +static const struct ina2xx_config ina2xx_config[] = {
> +	[ina219] = {
> +		    .config_default = INA219_CONFIG_DEFAULT,
> +		    .calibration_factor = 40960000,
> +		    .registers = INA219_REGISTERS,
> +		    .shunt_div = 100,
> +		    .bus_voltage_shift = 3,
> +		    .bus_voltage_lsb = 4000,
> +		    .power_lsb = 20000,
> +		    },
> +	[ina226] = {
> +		    .config_default = INA226_CONFIG_DEFAULT,
> +		    .calibration_factor = 5120000,
> +		    .registers = INA226_REGISTERS,
> +		    .shunt_div = 400,
> +		    .bus_voltage_shift = 0,
> +		    .bus_voltage_lsb = 1250,
> +		    .power_lsb = 25000,
> +		    },
> +};
> +
> +static int ina2xx_get_value(struct ina2xx_chip_info *chip, u8 reg,
> +			    unsigned int regval, int *val, int *uval)
> +{
> +	*val = 0;
> +
> +	switch (reg) {
> +	case INA2XX_SHUNT_VOLTAGE:
> +		/* signed register */
> +		*uval = DIV_ROUND_CLOSEST((s16) regval,
> +					  chip->config->shunt_div);
> +		return IIO_VAL_INT_PLUS_MICRO;
> +
> +	case INA2XX_BUS_VOLTAGE:
> +		*uval = (regval >> chip->config->bus_voltage_shift)
> +			* chip->config->bus_voltage_lsb;
> +		*val = *uval/1000000;

whitespace around / please

> +		*uval = *uval % 1000000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +
> +	case INA2XX_POWER:
> +		*uval = regval * chip->config->power_lsb;
> +		*val = *uval/1000000;
> +		*uval = *uval % 1000000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +
> +	case INA2XX_CURRENT:
> +		/* signed register, LSB=1mA (selected), in mA */
> +		*uval = (s16) regval * 1000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +
> +	default:
> +		/* programmer goofed */
> +		WARN_ON_ONCE(1);
> +	}
> +	return -EINVAL;
> +}
> +
> +static int ina2xx_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan,
> +			   int *val, int *val2, long mask)
> +{
> +	int ret;
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	unsigned int regval;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		ret = regmap_read(chip->regmap, chan->address, &regval);
> +		if (ret < 0)
> +			return ret;
> +
> +		return ina2xx_get_value(chip, chan->address, regval, val, val2);
> +
> +	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> +		*val = chip->avg;
> +		return IIO_VAL_INT;
> +
> +	case IIO_CHAN_INFO_INT_TIME:
> +		*val = 0;
> +		if (chan->address == INA2XX_SHUNT_VOLTAGE)
> +			*val2 = chip->its;
> +		else
> +			*val2 = chip->itb;
> +
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	/*
> +	 * sample freq is read only, it is a consequence of
> +	 * 1/AVG*(CT_bus+CT_shunt)
> +	 */
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		*val = DIV_ROUND_CLOSEST(1000000,
> +		       (chip->itb + chip->its) * chip->avg);
> +
> +		return IIO_VAL_INT;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * Available averaging rates for ina226. The indices correspond with
> + * the bit values expected by the chip (according to the ina226 datasheet,
> + * table 3 AVG bit settings, found at
> + * http://www.ti.com/lit/ds/symlink/ina226.pdf.
> + */
> +static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
> +
> +static unsigned int ina226_set_average(struct ina2xx_chip_info *chip,

retval should have type int

> +				       unsigned int val,
> +				       unsigned int *config)
> +{
> +	int bits;
> +
> +	if (val > 1024 || val < 1)
> +		return -EINVAL;
> +
> +	bits = find_closest(val, ina226_avg_tab,
> +			    ARRAY_SIZE(ina226_avg_tab));
> +
> +	chip->avg = ina226_avg_tab[bits];
> +
> +	*config &= ~INA226_AVG_MASK;
> +	*config |= INA226_SHIFT_AVG(bits) & INA226_AVG_MASK;
> +
> +	return 0;
> +}
> +
> +/* Conversion times in uS */
> +static const int ina226_conv_time_tab[] = { 140, 204, 332, 588, 1100,
> +					    2116, 4156, 8244};

maybe whitespace before }

> +
> +static unsigned int ina226_set_itb(struct ina2xx_chip_info *chip,
> +				   unsigned int val,
> +				   unsigned int *config)
> +{
> +	int bits;
> +
> +	if (val > 8244 || val < 140)
> +		return -EINVAL;
> +
> +	bits = find_closest(val, ina226_conv_time_tab,
> +			ARRAY_SIZE(ina226_conv_time_tab));
> +
> +	chip->itb = ina226_conv_time_tab[bits];
> +
> +	*config &= ~INA226_ITB_MASK;
> +	*config |= INA226_SHIFT_ITB(bits) & INA226_ITB_MASK;
> +
> +	return 0;
> +}
> +
> +static unsigned int ina226_set_its(struct ina2xx_chip_info *chip,

retval should have type int

> +				   unsigned int val,
> +				   unsigned int *config)
> +{
> +	int bits;
> +
> +	if (val > 8244 || val < 140)
> +		return -EINVAL;
> +
> +	bits = find_closest(val, ina226_conv_time_tab,
> +			ARRAY_SIZE(ina226_conv_time_tab));
> +
> +	chip->its = ina226_conv_time_tab[bits];
> +
> +	*config &= ~INA226_ITS_MASK;
> +	*config |= INA226_SHIFT_ITS(bits) & INA226_ITS_MASK;
> +
> +	return 0;
> +}
> +

drop dup newline

> +
> +static int ina2xx_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int val, int val2, long mask)
> +{
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	int ret = 0;
> +	unsigned int config, tmp;
> +
> +	if (iio_buffer_enabled(indio_dev))
> +		return -EBUSY;
> +
> +	mutex_lock(&chip->state_lock);
> +
> +	ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config);
> +	if (ret < 0)
> +		goto _err;
> +
> +	tmp = config;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> +		ret = ina226_set_average(chip, val, &tmp);
> +		break;
> +
> +	case IIO_CHAN_INFO_INT_TIME:
> +		if (chan->address == INA2XX_SHUNT_VOLTAGE)
> +			ret = ina226_set_its(chip, val, &tmp);
> +		else
> +			ret = ina226_set_itb(chip, val, &tmp);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	if (!ret && (tmp != config))
> +		ret = regmap_write(chip->regmap, INA2XX_CONFIG, tmp);
> +_err:
> +	mutex_unlock(&chip->state_lock);
> +
> +	return ret;
> +}
> +
> +
> +#define INA2XX_CHAN(_type, _index, _address) { \
> +	.type = _type, \
> +	.address = _address, \
> +	.indexed = 1, \
> +	.channel = (_index), \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
> +				   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
> +	.scan_index = (_index), \
> +	.scan_type = { \
> +		.sign = 'u', \
> +		.realbits = 16, \
> +		.storagebits = 16, \
> +	.endianness = IIO_BE, \
> +	} \
> +}
> +
> +/*Sampling Freq is a consequence of the integration times of the V channels.*/

whitespace after /* and before */ please

> +#define INA2XX_CHAN_VOLTAGE(_index, _address) { \
> +	.type = IIO_VOLTAGE, \
> +	.address = _address, \
> +	.indexed = 1, \
> +	.channel = (_index), \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			      BIT(IIO_CHAN_INFO_INT_TIME), \
> +	.scan_index = (_index), \
> +	.scan_type = { \
> +		.sign = 'u', \
> +		.realbits = 16, \
> +		.storagebits = 16, \
> +	.endianness = IIO_BE, \
> +	} \
> +}
> +

drop dup newline

> +
> +static const struct iio_chan_spec ina2xx_channels[] = {
> +	INA2XX_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
> +	INA2XX_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
> +	INA2XX_CHAN(IIO_CURRENT, 2, INA2XX_CURRENT),
> +	INA2XX_CHAN(IIO_POWER, 3, INA2XX_POWER),
> +	IIO_CHAN_SOFT_TIMESTAMP(4),
> +};
> +
> +
> +static s64 prev_ns;
> +
> +static int ina2xx_work_buffer(struct iio_dev *indio_dev)
> +{
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	unsigned short data[8];
> +	int bit, ret = 0, i = 0;
> +	unsigned long buffer_us = 0, elapsed_us = 0;
> +	s64 time_a, time_b;
> +	unsigned int alert;
> +
> +	time_a = iio_get_time_ns();
> +
> +	/*
> +	 * Because the timer thread and the chip conversion clock
> +	 * are asynchronous, the period difference will eventually
> +	 * result in reading V[k-1] again, or skip V[k] at time Tk.
> +	 * In order to resync the timer with the conversion process
> +	 * we check the ConVersionReadyFlag.
> +	 * On hardware that supports using the ALERT pin to toggle a
> +	 * GPIO a triggered buffer could be used instead.
> +	 * For now, we pay for that extra read of the ALERT register
> +	 */
> +	do {
> +		ret = regmap_read(chip->regmap, INA226_ALERT_MASK,
> +				  &alert);
> +		if (ret < 0)
> +			goto _err;
> +
> +		alert &= INA266_CVRF;
> +		trace_printk("Conversion ready: %d\n", !!alert);
> +
> +	} while (!alert);
> +
> +	/*
> +	 * Single register reads: bulk_read will not work with ina226
> +	 * as there is no auto-increment of the address register for
> +	 * data length longer than 16bits.
> +	 */
> +	for_each_set_bit(bit, indio_dev->active_scan_mask,
> +			 indio_dev->masklength) {
> +		unsigned int val;
> +
> +		ret = regmap_read(chip->regmap,
> +				  INA2XX_SHUNT_VOLTAGE + bit, &val);
> +		if (ret < 0)
> +			goto _err;
> +
> +		data[i++] = val;
> +	}
> +
> +	time_b = iio_get_time_ns();
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev,
> +					   (unsigned int *)data, time_a);
> +
> +	buffer_us = (unsigned long)(time_b - time_a) / 1000;
> +	elapsed_us = (unsigned long)(time_a - prev_ns) / 1000;
> +
> +	trace_printk("uS: elapsed: %lu, buf: %lu\n", elapsed_us, buffer_us);
> +
> +	prev_ns = time_a;
> +
> +_err:
> +	return buffer_us;
> +};
> +
> +static int ina2xx_capture_thread(void *data)
> +{
> +	struct iio_dev *indio_dev = (struct iio_dev *)data;
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	unsigned int sampling_us = (chip->itb + chip->its) * chip->avg;
> +	unsigned long buffer_us;
> +
> +	/*
> +	 * Poll a bit faster than the chip internal Fs, in case
> +	 * we wish to sync with the conversion ready flag.
> +	 */
> +	sampling_us -= 200;
> +
> +	do {
> +		buffer_us = ina2xx_work_buffer(indio_dev);
> +
> +		if (sampling_us > buffer_us)
> +			udelay(sampling_us - buffer_us);
> +
> +	} while (!kthread_should_stop());
> +
> +	return 0;
> +}
> +
> +int ina2xx_buffer_enable(struct iio_dev *indio_dev)
> +{
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	unsigned int sampling_us = (chip->itb + chip->its) * chip->avg;
> +
> +	trace_printk("Enabling buffer w/ scan_mask %02x, freq = %d, avg =%u\n",
> +		     (unsigned int)(*indio_dev->active_scan_mask),
> +		     1000000/sampling_us, chip->avg);
> +
> +	trace_printk("Expected work period: %u us\n", sampling_us);
> +
> +	prev_ns = iio_get_time_ns();
> +
> +	chip->task = kthread_run(ina2xx_capture_thread, (void *)indio_dev,
> +				 "ina2xx-%uus", sampling_us);
> +
> +	return PTR_ERR_OR_ZERO(chip->task);
> +}
> +
> +int ina2xx_buffer_disable(struct iio_dev *indio_dev)
> +{
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (chip->task) {
> +		kthread_stop(chip->task);
> +		chip->task = NULL;
> +	}
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops ina2xx_setup_ops = {
> +	.postenable = &ina2xx_buffer_enable,
> +	.postdisable = &ina2xx_buffer_disable,
> +};
> +
> +static int ina2xx_debug_reg(struct iio_dev *indio_dev,
> +			    unsigned reg, unsigned writeval, unsigned *readval)
> +{
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (!readval)
> +		return regmap_write(chip->regmap, reg, writeval);
> +
> +	return regmap_read(chip->regmap, reg, readval);
> +}
> +
> +/* frequencies matching the cummulated integration times for vshunt and vbus */

cumulated

> +static IIO_CONST_ATTR_INT_TIME_AVAIL("140 204 332 588 1100 2116 4156 8244");
> +
> +static struct attribute *ina2xx_attributes[] = {
> +	&iio_const_attr_integration_time_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group ina2xx_attribute_group = {
> +	.attrs = ina2xx_attributes,
> +};
> +
> +static const struct iio_info ina2xx_info = {
> +	.debugfs_reg_access = &ina2xx_debug_reg,
> +	.read_raw = &ina2xx_read_raw,
> +	.write_raw = &ina2xx_write_raw,
> +	.attrs = &ina2xx_attribute_group,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +/* Initialize the configuration and calibration registers. */
> +static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)
> +{
> +	u16 regval;
> +	int ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
> +
> +	if (ret < 0)
> +		return ret;
> +	/*
> +	 * Set current LSB to 1mA, shunt is in uOhms
> +	 * (equation 13 in datasheet). We hardcode a Current_LSB
> +	 * of 1.0 x10-6. The only remaining parameter is RShunt

full stop

> +	 * There is no need to expose the CALIBRATION register
> +	 * to the user for now.
> +	 */
> +	regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
> +			    chip->rshunt);
> +
> +	return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);
> +}
> +
> +static int ina2xx_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct ina2xx_chip_info *chip;
> +	struct iio_dev *indio_dev;
> +	struct iio_buffer *buffer;
> +	int ret;
> +	unsigned int val;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	chip = iio_priv(indio_dev);
> +
> +	chip->config = &ina2xx_config[id->driver_data];
> +
> +	if (of_property_read_u32(client->dev.of_node,
> +				 "shunt-resistor", &val) < 0) {
> +		struct ina2xx_platform_data *pdata =
> +		    dev_get_platdata(&client->dev);
> +
> +		if (pdata)
> +			val = pdata->shunt_uohms;
> +		else
> +			val = INA2XX_RSHUNT_DEFAULT;
> +	}
> +
> +	if (val <= 0 || val > chip->config->calibration_factor)
> +		return -ENODEV;
> +
> +	chip->rshunt = val;
> +
> +	ina2xx_regmap_config.max_register = chip->config->registers;
> +
> +	mutex_init(&chip->state_lock);
> +
> +	/* this is only used for device removal purposes */
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	indio_dev->name = id->name;
> +	indio_dev->channels = ina2xx_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ina2xx_channels);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &ina2xx_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
> +
> +	chip->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
> +	if (IS_ERR(chip->regmap)) {
> +		dev_err(&client->dev, "failed to allocate register map\n");
> +		return PTR_ERR(chip->regmap);
> +	}
> +
> +	/* Patch the current config register with default. */
> +	val = chip->config->config_default;
> +
> +	if (id->driver_data == ina226) {
> +		ina226_set_average(chip, INA226_DEFAULT_AVG, &val);
> +		ina226_set_itb(chip, INA226_DEFAULT_IT, &val);
> +		ina226_set_its(chip, INA226_DEFAULT_IT, &val);
> +	}
> +
> +	ret = ina2xx_init(chip, val);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "error configuring the device: %d\n",
> +			ret);
> +		return -ENODEV;
> +	}
> +
> +	buffer = devm_iio_kfifo_allocate(&indio_dev->dev);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	indio_dev->setup_ops = &ina2xx_setup_ops;
> +
> +	iio_device_attach_buffer(indio_dev, buffer);
> +
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +
> +static int ina2xx_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_destroy(&chip->state_lock);

needed?

> +
> +	/* Powerdown */
> +	ret = regmap_update_bits(chip->regmap, INA2XX_CONFIG,
> +				  INA2XX_MODE_MASK, 0);
> +
> +	iio_device_unregister(indio_dev);

not needed since devm_iio_device_register() is used

> +
> +	return ret;
> +}
> +
> +
> +static const struct i2c_device_id ina2xx_id[] = {
> +	{"ina219", ina219},
> +	{"ina220", ina219},
> +	{"ina226", ina226},
> +	{"ina230", ina226},
> +	{"ina231", ina226},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, ina2xx_id);
> +
> +static struct i2c_driver ina2xx_driver = {
> +	.driver = {
> +		   .name = KBUILD_MODNAME,
> +	},
> +	.probe = ina2xx_probe,
> +	.remove = ina2xx_remove,
> +	.id_table = ina2xx_id,
> +};
> +
> +module_i2c_driver(ina2xx_driver);
> +
> +MODULE_AUTHOR("Marc Titinger <marc.titinger@baylibre.com>");
> +MODULE_DESCRIPTION("Texas Instruments INA2XX ADC driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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