On 07/12/15 09:09, Marc Titinger wrote:
> 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).
> 
> This will produce a stream of up to fours channels plus a 64bits
> timestamps (ns).
> 
> Tested with ina226, on BeagleBoneBlack.
> 
> Datasheet: http://www.ti.com/lit/gpn/ina226
> 
> Signed-off-by: Marc Titinger <mtitin...@baylibre.com>
One small (largely semantic) issue with balanced post enable / pre disable
(rather than post disable) for the buffer.

Otherwise fine so I'll apply this and fix that up in the process.

Applied to the togreg branch of iio.git - pushed out as testing.
Was a bit of additional fuzz but I think the merge was straightforward.

Long term - might move this out to a meter directory along with the
various power monitors that are in staging/iio/meter.

Thanks,

Jonathan
> ---
>  drivers/iio/adc/Kconfig      |  10 +
>  drivers/iio/adc/Makefile     |   1 +
>  drivers/iio/adc/ina2xx-adc.c | 670 
> +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 681 insertions(+)
>  create mode 100644 drivers/iio/adc/ina2xx-adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index eb0cd89..e5fdc7d 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_ADC
> +     tristate "Texas Instruments INA2xx Power Monitors IIO driver"
> +     depends on I2C && !SENSORS_INA2XX
> +     select REGMAP_I2C
> +     select IIO_BUFFER
> +     select IIO_KFIFO_BUF
> +     help
> +       Say yes here to build support for TI INA2xx family of Power Monitors.
> +       This driver is mutually exclusive with the HWMON version.
> +
>  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..2869b0ef 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-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>  obj-$(CONFIG_MAX1027) += max1027.o
>  obj-$(CONFIG_MAX1363) += max1363.o
> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> new file mode 100644
> index 0000000..0e7c474
> --- /dev/null
> +++ b/drivers/iio/adc/ina2xx-adc.c
> @@ -0,0 +1,670 @@
> +/*
> + * 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-fel...@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 */
> +#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)
> +
> +#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 */
> +#define INA226_ITS_MASK              GENMASK(5, 3)
> +#define INA226_SHIFT_ITS(val)        ((val) << 3)
> +
> +/* Cosmetic macro giving the sampling period for a full P=UxI cycle */
> +#define SAMPLING_PERIOD(c)   ((c->int_time_vbus + c->int_time_vshunt) \
> +                              * c->avg)
> +
> +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 const struct regmap_config ina2xx_regmap_config = {
> +     .reg_bits = 8,
> +     .val_bits = 16,
> +     .max_register = INA2XX_MAX_REGISTERS,
> +     .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 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;
> +     s64 prev_ns;    /* track buffer capture time, check for underruns*/
> +     int int_time_vbus; /* Bus voltage integration time uS */
> +     int int_time_vshunt; /* Shunt voltage integration time uS */
> +};
> +
> +static const struct ina2xx_config ina2xx_config[] = {
> +     [ina219] = {
> +                 .config_default = INA219_CONFIG_DEFAULT,
> +                 .calibration_factor = 40960000,
> +                 .shunt_div = 100,
> +                 .bus_voltage_shift = 3,
> +                 .bus_voltage_lsb = 4000,
> +                 .power_lsb = 20000,
> +                 },
> +     [ina226] = {
> +                 .config_default = INA226_CONFIG_DEFAULT,
> +                 .calibration_factor = 5120000,
> +                 .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;
> +             *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->int_time_vshunt;
> +             else
> +                     *val2 = chip->int_time_vbus;
> +
> +             return IIO_VAL_INT_PLUS_MICRO;
> +
> +     case IIO_CHAN_INFO_SAMP_FREQ:
> +             /*
> +              * Sample freq is read only, it is a consequence of
> +              * 1/AVG*(CT_bus+CT_shunt).
> +              */
> +             *val = DIV_ROUND_CLOSEST(1000000, SAMPLING_PERIOD(chip));
> +
> +             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 int ina226_set_average(struct ina2xx_chip_info *chip, 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 };
> +
> +static int ina226_set_int_time_vbus(struct ina2xx_chip_info *chip,
> +                                 unsigned int val_us, unsigned int *config)
> +{
> +     int bits;
> +
> +     if (val_us > 8244 || val_us < 140)
> +             return -EINVAL;
> +
> +     bits = find_closest(val_us, ina226_conv_time_tab,
> +                     ARRAY_SIZE(ina226_conv_time_tab));
> +
> +     chip->int_time_vbus = ina226_conv_time_tab[bits];
> +
> +     *config &= ~INA226_ITB_MASK;
> +     *config |= INA226_SHIFT_ITB(bits) & INA226_ITB_MASK;
> +
> +     return 0;
> +}
> +
> +static int ina226_set_int_time_vshunt(struct ina2xx_chip_info *chip,
> +                                   unsigned int val_us, unsigned int *config)
> +{
> +     int bits;
> +
> +     if (val_us > 8244 || val_us < 140)
> +             return -EINVAL;
> +
> +     bits = find_closest(val_us, ina226_conv_time_tab,
> +                     ARRAY_SIZE(ina226_conv_time_tab));
> +
> +     chip->int_time_vshunt = ina226_conv_time_tab[bits];
> +
> +     *config &= ~INA226_ITS_MASK;
> +     *config |= INA226_SHIFT_ITS(bits) & INA226_ITS_MASK;
> +
> +     return 0;
> +}
> +
> +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;
> +     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_int_time_vshunt(chip, val2, &tmp);
> +             else
> +                     ret = ina226_set_int_time_vbus(chip, val2, &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 Voltage channels.
> + */
> +#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, \
> +     } \
> +}
> +
> +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 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, i = 0;
> +     unsigned long buffer_us, elapsed_us;
> +     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)
> +                     return ret;
> +
> +             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)
> +                     return ret;
> +
> +             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 - chip->prev_ns) / 1000;
> +
> +     trace_printk("uS: elapsed: %lu, buf: %lu\n", elapsed_us, buffer_us);
> +
> +     chip->prev_ns = time_a;
> +
> +     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 = SAMPLING_PERIOD(chip);
> +     int 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 (buffer_us < 0)
> +                     return buffer_us;
> +
> +             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 = SAMPLING_PERIOD(chip);
> +
> +     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);
> +
> +     chip->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,
Sorry, only just noticed this.  The postenable pairs with predisable
(inside and outside the state change for the two pairs). I might just
fix this up when applying (should be predisable)

> +};
> +
> +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);
> +}
> +
> +/* Possible integration times for vshunt and vbus */
> +static IIO_CONST_ATTR_INT_TIME_AVAIL \
> + ("0.000140 0.000204 0.000332 0.000588 0.001100 0.002116 0.004156 0.008244");
> +
> +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.
> +      * 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;
> +
> +     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_int_time_vbus(chip, INA226_DEFAULT_IT, &val);
> +             ina226_set_int_time_vshunt(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 iio_device_register(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);
> +
> +     iio_device_unregister(indio_dev);
> +
> +     /* Powerdown */
> +     return regmap_update_bits(chip->regmap, INA2XX_CONFIG,
> +                               INA2XX_MODE_MASK, 0);
> +}
> +
> +
> +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.titin...@baylibre.com>");
> +MODULE_DESCRIPTION("Texas Instruments INA2XX ADC driver");
> +MODULE_LICENSE("GPL v2");
> 

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