Re: [RFC 1/4] iio: ina2xx: add direct IO support for TI INA2xx Power Monitors

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On Tue, Nov 10, 2015 at 6:07 PM, Marc Titinger <mtitinger@xxxxxxxxxxxx> wrote:
> Basic support or direct IO raw read, with averaging attribute.
> Values are RAW, INT_PLUS_MICRO (Volt/Ampere/Watt).
>
> IIO context has 1 devices:
Is this from libiio right? Perhaps you should specify this:

"libiio context has 1 devices"

>      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
>       2 device-specific attributes found:
>                 attr 0: in_calibscale value: 10000
>                 attr 1: in_mean_raw value: 4
>
>

Link to datasheet?

> Signed-off-by: Marc Titinger <mtitinger@xxxxxxxxxxxx>
> ---
>  drivers/iio/adc/Kconfig      |   9 +
>  drivers/iio/adc/Makefile     |   1 +
>  drivers/iio/adc/ina2xx-iio.c | 404 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 414 insertions(+)
>  create mode 100644 drivers/iio/adc/ina2xx-iio.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index eb0cd89..b648051 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -10,6 +10,15 @@ config AD_SIGMA_DELTA
>         select IIO_BUFFER
>         select IIO_TRIGGERED_BUFFER
>
> +config INA2XX_IIO
> +        tristate "Texas Instruments INA2xx Power Monitors IIO driver"
> +       depends on I2C

Since you are using regmap you should select it here.

> +        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 symbol should be in alphabetical order.

>  config AD7266
>         tristate "Analog Devices AD7265/AD7266 ADC driver"
>         depends on SPI_MASTER
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index a096210..e6a844a 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -5,6 +5,7 @@
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
>  obj-$(CONFIG_AD7266) += ad7266.o
> +obj-$(CONFIG_INA2XX_IIO) += ina2xx-iio.o

The same here.

>  obj-$(CONFIG_AD7291) += ad7291.o
>  obj-$(CONFIG_AD7298) += ad7298.o
>  obj-$(CONFIG_AD7923) += ad7923.o
> diff --git a/drivers/iio/adc/ina2xx-iio.c b/drivers/iio/adc/ina2xx-iio.c
> new file mode 100644
> index 0000000..257d8d5
> --- /dev/null
> +++ b/drivers/iio/adc/ina2xx-iio.c
> @@ -0,0 +1,404 @@
> +/*
> + * 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@xxxxxx>
> + *
> + * Licensed under the GPL-2 or later.

If you know the I2C address its recommended to mention it here.

> + */
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/platform_data/ina2xx.h>
> +
> +#include <linux/util_macros.h>

Nice, didn't know about this :).

> +
> +/*
> + * 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 INA2XX_RSHUNT_DEFAULT           10000
> +
> +/* bit mask for reading the averaging setting in the configuration register */
> +#define INA226_AVG_RD_MASK              0x0E00
> +#define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
> +#define INA226_SHIFT_AVG(val)           ((val) << 9)
> +
> +static struct regmap_config ina2xx_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 16,
Specify here which registers are cacheable, read/write.

> +};
> +
> +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 iio_dev *indio_dev;
> +       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);
> +               *val = *uval/1000000;
> +               *uval = *uval - *val*1000000;
> +               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 - *val*1000000;
> +               return IIO_VAL_INT_PLUS_MICRO;
> +
> +       case INA2XX_POWER:
> +               *uval = regval * chip->config->power_lsb;
> +               *val = *uval/1000000;
> +               *uval = *uval - *val*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);
> +
> +       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;
> +}
> +
> +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;
> +
> +       default:
> +               ret = -EINVAL;
> +       }
> +
> +       if (!ret && (tmp != config))
> +               ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
> +_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_AVERAGE_RAW) | \
> +                                  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 const struct iio_info ina2xx_info = {
> +       .read_raw = &ina2xx_read_raw,
> +       .write_raw = &ina2xx_write_raw,
> +       .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);
> +       chip->indio_dev = 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);
> +
> +       ret = ina2xx_init(chip, val);
> +       if (ret < 0) {
> +               dev_err(&client->dev, "error configuring the device: %d\n",
> +                       ret);
> +               return -ENODEV;
> +       }
> +
> +       return iio_device_register(indio_dev);

If there is no reverse operation for ina2xx_init (e.g ina2xx_poweroff) then here
you can use devm_iio_device_register and completely remove
ina2xx_remove function.


> +}
> +
> +static int ina2xx_remove(struct i2c_client *client)
> +{
> +       struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +       iio_device_unregister(indio_dev);
> +
> +       return 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.titinger@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Texas Instruments INA2XX ADC driver");
> +MODULE_LICENSE("GPL v2");
--
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