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    Subject[RFC 6/9] iio: ina2xx: add direct IO support for TI INA2xx Power Monitors
    Date
    Basic support or direct IO raw read, with averaging attribute.
    Values are RAW, INT_PLUS_MICRO (Volt/Ampere/Watt).

    Output of iio_info:

    iio:device0: ina226
    4 channels found:
    power3: (input)
    1 channel-specific attributes found:
    attr 0: raw value: 1.150000
    voltage0: (input)
    1 channel-specific attributes found:
    attr 0: raw value: 0.000003
    voltage1: (input)
    1 channel-specific attributes found:
    attr 0: raw value: 4.277500
    current2: (input)
    1 channel-specific attributes found:
    attr 0: raw value: 0.268000
    4 device-specific attributes found:
    attr 0: sampling_frequency_available value: 61 120 236...
    attr 1: in_averaging_steps value: 4
    attr 2: in_calibscale value: 10000
    attr 3: in_sampling_frequency value: 1506

    Tested with ina226, on BeagleBoneBlack.

    Datasheet: http://www.ti.com/lit/gpn/ina226

    Signed-off-by: Marc Titinger <mtitinger@baylibre.com>
    ---
    drivers/iio/adc/Kconfig | 9 +
    drivers/iio/adc/Makefile | 1 +
    drivers/iio/adc/ina2xx-iio.c | 515 +++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 525 insertions(+)
    create mode 100644 drivers/iio/adc/ina2xx-iio.c

    diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
    index 50c103d..ebbfff9 100644
    --- a/drivers/iio/adc/Kconfig
    +++ b/drivers/iio/adc/Kconfig
    @@ -183,6 +183,15 @@ config EXYNOS_ADC
    To compile this driver as a module, choose M here: the module will be
    called exynos_adc.

    +config INA2XX_IIO
    + tristate "Texas Instruments INA2xx Power Monitors IIO driver"
    + depends on I2C
    + select REGMAP_I2C
    + help
    + Say yes here to build support for TI INA2xx familly Power Monitors.
    +
    + Note that this is not the existing hwmon interface for this device.
    +
    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..d4dd908
    --- /dev/null
    +++ b/drivers/iio/adc/ina2xx-iio.c
    @@ -0,0 +1,515 @@
    +/*
    + * 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/iio/iio.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 */
    +#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
    +
    +/* 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_FREQ 455
    +
    +#define INA2XX_RSHUNT_DEFAULT 10000
    +
    +/* bit mask for reading the averaging setting in the configuration register */
    +#define INA226_AVG_RD_MASK GENMASK(11, 9)
    +#define INA226_READ_AVG(reg) (((reg) & INA226_AVG_RD_MASK) >> 9)
    +#define INA226_SHIFT_AVG(val) ((val) << 9)
    +
    +#define INA226_SFREQ_RD_MASK GENMASK(8, 3)
    +
    +
    +static bool ina2xx_is_writeable_reg(struct device *dev, unsigned int reg)
    +{
    + return (reg == INA2XX_CONFIG) || (reg == INA2XX_CALIBRATION);
    +}
    +
    +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 {
    + const struct ina2xx_config *config;
    + struct mutex state_lock;
    + long rshunt;
    + int avg;
    + int freq;
    + int period_us;
    + struct regmap *regmap;
    +};
    +
    +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;
    + *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;
    +
    + case INA2XX_CALIBRATION:
    + *val = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
    + regval);
    + return IIO_VAL_INT;
    +
    + 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_AVERAGE_RAW:
    + *val = chip->avg;
    + return IIO_VAL_INT;
    +
    + case IIO_CHAN_INFO_CALIBSCALE:
    + ret = regmap_read(chip->regmap, INA2XX_CALIBRATION, &regval);
    + if (ret < 0)
    + return ret;
    +
    + return ina2xx_get_value(chip, INA2XX_CALIBRATION, regval,
    + val, val2);
    +
    + case IIO_CHAN_INFO_SAMP_FREQ:
    + *val = chip->freq;
    + return IIO_VAL_INT;
    +
    + default:
    + return -EINVAL;
    + }
    +
    + return 0;
    +}
    +
    +static int ina2xx_calibrate(struct ina2xx_chip_info *chip)
    +{
    + u16 val = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
    + chip->rshunt);
    +
    + return regmap_write(chip->regmap, INA2XX_CALIBRATION, val);
    +}
    +
    +
    +/*
    + * 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,
    + 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_RD_MASK;
    + *config |= INA226_SHIFT_AVG(bits) & INA226_AVG_RD_MASK;
    +
    + return 0;
    +}
    +
    +/* Conversion times in uS */
    +static const int ina226_conv_time_tab[] = { 140, 204, 332, 588, 1100,
    + 2116, 4156, 8244};
    +
    +static unsigned int ina226_set_frequency(struct ina2xx_chip_info *chip,
    + unsigned int val,
    + unsigned int *config)
    +{
    + int bits;
    +
    + if (val > 3550 || val < 50)
    + return -EINVAL;
    +
    + /* integration time in uS, for both voltage channels */
    + val = DIV_ROUND_CLOSEST(1000000, 2 * val);
    +
    + bits = find_closest(val, ina226_conv_time_tab,
    + ARRAY_SIZE(ina226_conv_time_tab));
    +
    + chip->period_us = 2 * ina226_conv_time_tab[bits];
    +
    + chip->freq = DIV_ROUND_CLOSEST(1000000, chip->period_us);
    +
    + *config &= ~INA226_SFREQ_RD_MASK;
    + *config |= (bits << 3) | (bits << 6);
    +
    + 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 = 0;
    + unsigned int config, tmp;
    +
    + 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_AVERAGE_RAW:
    +
    + ret = ina226_set_average(chip, val, &tmp);
    + break;
    +
    + case IIO_CHAN_INFO_SAMP_FREQ:
    +
    + ret = ina226_set_frequency(chip, val, &tmp);
    + break;
    +
    + default:
    + ret = -EINVAL;
    + }
    +
    + if (!ret && (tmp != config))
    + ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
    +_err:
    + mutex_unlock(&chip->state_lock);
    +
    + return ret;
    +}
    +
    +
    +static ssize_t ina2xx_averaging_steps_show(struct device *dev,
    + struct device_attribute *attr,
    + char *buf)
    +{
    + struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
    +
    + return sprintf(buf, "%d\n", chip->avg);
    +}
    +
    +
    +static ssize_t ina2xx_averaging_steps_store(struct device *dev,
    + struct device_attribute *attr,
    + const char *buf, size_t len)
    +{
    + unsigned long val;
    + int ret;
    +
    + ret = kstrtoul((const char *) buf, 10, &val);
    + if (ret)
    + return -EINVAL;
    +
    + /* unexposed missuse of INFO_AVERAGE_RAW, until a proper ABI for the
    + * averaging steps setting is specified.
    + */
    + ret = ina2xx_write_raw(dev_to_iio_dev(dev), NULL, val, 0,
    + IIO_CHAN_INFO_AVERAGE_RAW);
    + if (ret < 0)
    + return ret;
    +
    + return len;
    +}
    +
    +
    +#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_CALIBSCALE), \
    + .scan_index = (_index), \
    + .scan_type = { \
    + .sign = 'u', \
    + .realbits = 16, \
    + .storagebits = 16, \
    + .shift = 0, \
    + .endianness = IIO_BE, \
    + } \
    +}
    +
    +static const struct iio_chan_spec ina2xx_channels[] = {
    + INA2XX_CHAN(IIO_VOLTAGE, 0, INA2XX_SHUNT_VOLTAGE),
    + INA2XX_CHAN(IIO_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_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 */
    +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("61 120 236 455 850 1506 2450 3571");
    +
    +static IIO_DEVICE_ATTR(in_averaging_steps, S_IRUGO | S_IWUSR,
    + ina2xx_averaging_steps_show,
    + ina2xx_averaging_steps_store, 0);
    +
    +static struct attribute *ina2xx_attributes[] = {
    + &iio_dev_attr_in_averaging_steps.dev_attr.attr,
    + &iio_const_attr_sampling_frequency_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)
    +{
    + 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).
    + */
    + return ina2xx_calibrate(chip);
    +}
    +
    +static int ina2xx_probe(struct i2c_client *client,
    + const struct i2c_device_id *id)
    +{
    + struct ina2xx_chip_info *chip;
    + struct iio_dev *indio_dev;
    + 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);
    +
    + /* set the device type */
    + 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;
    +
    + 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_frequency(chip, INA226_DEFAULT_FREQ, &val);
    + }
    +
    + ret = ina2xx_init(chip, val);
    + if (ret < 0) {
    + dev_err(&client->dev, "error configuring the device: %d\n",
    + ret);
    + return -ENODEV;
    + }
    +
    + return devm_iio_device_register(&client->dev, indio_dev);
    +}
    +
    +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,
    + .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");
    --
    1.9.1


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