Re: [PATCH v2 2/3] iio: adc: Fix integration time/averaging for INA219/220

Jonathan Cameron
2017-05-24T19:50:52Z

On Wed, 24 May 2017 02:09:06 +0200
Stefan Brüns <stefan.bruens@rwth-aachen.de> wrote:

> INA226/230/231 has integration times per voltage channel and common
> averaging setting for both channels, while the INA219/220 only has a
> combined integration time/averaging setting per channel.
> Only expose the averaging attribute for the INA226, and expose the correct
> integration times for the INA219.
>
> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
One comment inline, but not really anything I want you to change.

I would like some input from Marc or perhaps Andrew on this though.
> ---
> drivers/iio/adc/ina2xx-adc.c | 204 ++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 182 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> index bba10a1b2fcb..232c0b80d658 100644
> --- a/drivers/iio/adc/ina2xx-adc.c
> +++ b/drivers/iio/adc/ina2xx-adc.c
> @@ -49,6 +49,7 @@
>
> /* settings - depend on use case */
> #define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
> +#define INA219_DEFAULT_IT 532
> #define INA226_CONFIG_DEFAULT 0x4327
> #define INA226_DEFAULT_AVG 4
> #define INA226_DEFAULT_IT 1110
> @@ -56,19 +57,24 @@
> #define INA2XX_RSHUNT_DEFAULT 10000
>
> /*
> - * bit mask for reading the averaging setting in the configuration register
> + * bit masks for reading the settings in the configuration register
> * FIXME: use regmap_fields.
> */
> #define INA2XX_MODE_MASK GENMASK(3, 0)
>
> +/* Averaging for VBus/VShunt/Power */
> #define INA226_AVG_MASK GENMASK(11, 9)
> #define INA226_SHIFT_AVG(val) ((val) << 9)
>
> /* Integration time for VBus */
> +#define INA219_ITB_MASK GENMASK(10, 7)
> +#define INA219_SHIFT_ITB(val) ((val) << 7)
> #define INA226_ITB_MASK GENMASK(8, 6)
> #define INA226_SHIFT_ITB(val) ((val) << 6)
>
> /* Integration time for VShunt */
> +#define INA219_ITS_MASK GENMASK(6, 3)
> +#define INA219_SHIFT_ITS(val) ((val) << 3)
> #define INA226_ITS_MASK GENMASK(5, 3)
> #define INA226_SHIFT_ITS(val) ((val) << 3)
>
> @@ -108,6 +114,7 @@ struct ina2xx_config {
> int bus_voltage_shift;
> int bus_voltage_lsb; /* uV */
> int power_lsb; /* uW */
> + enum ina2xx_ids chip_id;
I wonder if it would be cleaner to have someting more
specific than simply an ID? Chances are as more parts
get added we'll get a steadily growing list of quirks
on different sets of them.

Mind you can always make that sort of generalization if /
when it is needed ;)
> };
>
> struct ina2xx_chip_info {
> @@ -130,6 +137,7 @@ static const struct ina2xx_config ina2xx_config[] = {
> .bus_voltage_shift = 3,
> .bus_voltage_lsb = 4000,
> .power_lsb = 20000,
> + .chip_id = ina219,
> },
> [ina226] = {
> .config_default = INA226_CONFIG_DEFAULT,
> @@ -138,6 +146,7 @@ static const struct ina2xx_config ina2xx_config[] = {
> .bus_voltage_shift = 0,
> .bus_voltage_lsb = 1250,
> .power_lsb = 25000,
> + .chip_id = ina226,
> },
> };
>
> @@ -283,6 +292,66 @@ static int ina226_set_int_time_vshunt(struct ina2xx_chip_info *chip,
> return 0;
> }
>
> +/* Conversion times in uS. */
> +static const int ina219_conv_time_tab_subsample[] = { 84, 148, 276, 532 };
> +static const int ina219_conv_time_tab_average[] = { 532, 1060, 2130, 4260,
> + 8510, 17020, 34050, 68100};
> +
> +static int ina219_lookup_int_time(unsigned int *val_us, int *bits)
> +{
> + if (*val_us > 68100 || *val_us < 84)
> + return -EINVAL;
> +
> + if (*val_us <= 532) {
> + *bits = find_closest(*val_us, ina219_conv_time_tab_subsample,
> + ARRAY_SIZE(ina219_conv_time_tab_subsample));
> + *val_us = ina219_conv_time_tab_subsample[*bits];
> + } else {
> + *bits = find_closest(*val_us, ina219_conv_time_tab_average,
> + ARRAY_SIZE(ina219_conv_time_tab_average));
> + *val_us = ina219_conv_time_tab_average[*bits];
> + *bits |= 0x8;
> + }
> +
> + return 0;
> +}
> +
> +static int ina219_set_int_time_vbus(struct ina2xx_chip_info *chip,
> + unsigned int val_us, unsigned int *config)
> +{
> + int bits, ret;
> + unsigned int val_us_best = val_us;
> +
> + ret = ina219_lookup_int_time(&val_us_best, &bits);
> + if (ret)
> + return ret;
> +
> + chip->int_time_vbus = val_us_best;
> +
> + *config &= ~INA219_ITB_MASK;
> + *config |= INA219_SHIFT_ITB(bits) & INA219_ITB_MASK;
> +
> + return 0;
> +}
> +
> +static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
> + unsigned int val_us, unsigned int *config)
> +{
> + int bits, ret;
> + unsigned int val_us_best = val_us;
> +
> + ret = ina219_lookup_int_time(&val_us_best, &bits);
> + if (ret)
> + return ret;
> +
> + chip->int_time_vshunt = val_us_best;
> +
> + *config &= ~INA219_ITS_MASK;
> + *config |= INA219_SHIFT_ITS(bits) & INA219_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)
> @@ -308,10 +377,21 @@ static int ina2xx_write_raw(struct iio_dev *indio_dev,
> 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);
> + if (chip->config->chip_id == ina226) {
> + 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);
> + } else {
> + if (chan->address == INA2XX_SHUNT_VOLTAGE)
> + ret = ina219_set_int_time_vshunt(chip, val2,
> + &tmp);
> + else
> + ret = ina219_set_int_time_vbus(chip, val2,
> + &tmp);
> + }
> break;
>
> default:
> @@ -412,7 +492,24 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
> return len;
> }
>
> -#define INA2XX_CHAN(_type, _index, _address) { \
> +#define INA219_CHAN(_type, _index, _address) { \
> + .type = (_type), \
> + .address = (_address), \
> + .indexed = 1, \
> + .channel = (_index), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> + BIT(IIO_CHAN_INFO_SCALE), \
> + .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> + .scan_index = (_index), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 16, \
> + .storagebits = 16, \
> + .endianness = IIO_CPU, \
> + } \
> +}
> +
> +#define INA226_CHAN(_type, _index, _address) { \
> .type = (_type), \
> .address = (_address), \
> .indexed = 1, \
> @@ -434,7 +531,25 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
> * Sampling Freq is a consequence of the integration times of
> * the Voltage channels.
> */
> -#define INA2XX_CHAN_VOLTAGE(_index, _address) { \
> +#define INA219_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_SCALE) | \
> + BIT(IIO_CHAN_INFO_INT_TIME), \
> + .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> + .scan_index = (_index), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 16, \
> + .storagebits = 16, \
> + .endianness = IIO_LE, \
> + } \
> +}
> +
> +#define INA226_CHAN_VOLTAGE(_index, _address) { \
> .type = IIO_VOLTAGE, \
> .address = (_address), \
> .indexed = 1, \
> @@ -453,11 +568,20 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
> } \
> }
>
> -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_POWER, 2, INA2XX_POWER),
> - INA2XX_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
> +
> +static const struct iio_chan_spec ina226_channels[] = {
> + INA226_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
> + INA226_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
> + INA226_CHAN(IIO_POWER, 2, INA2XX_POWER),
> + INA226_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
> + IIO_CHAN_SOFT_TIMESTAMP(4),
> +};
> +
> +static const struct iio_chan_spec ina219_channels[] = {
> + INA219_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
> + INA219_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
> + INA219_CHAN(IIO_POWER, 2, INA2XX_POWER),
> + INA219_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
> IIO_CHAN_SOFT_TIMESTAMP(4),
> };
>
> @@ -592,7 +716,14 @@ static int ina2xx_debug_reg(struct iio_dev *indio_dev,
> }
>
> /* 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 IIO_CONST_ATTR_NAMED(ina219_integration_time_available,
> + integration_time_available,
> + "0.000084 0.000148 0.000276 0.000532 0.001060 0.002130 0.004260 0.008510 0.017020 0.034050 0.068100");
> +
> +static IIO_CONST_ATTR_NAMED(ina226_integration_time_available,
> + integration_time_available,
> + "0.000140 0.000204 0.000332 0.000588 0.001100 0.002116 0.004156 0.008244");
> +
>
> static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR,
> ina2xx_allow_async_readout_show,
> @@ -602,20 +733,39 @@ static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO | S_IWUSR,
> ina2xx_shunt_resistor_show,
> ina2xx_shunt_resistor_store, 0);
>
> -static struct attribute *ina2xx_attributes[] = {
> +static struct attribute *ina219_attributes[] = {
> + &iio_dev_attr_in_allow_async_readout.dev_attr.attr,
> + &iio_const_attr_ina219_integration_time_available.dev_attr.attr,
> + &iio_dev_attr_in_shunt_resistor.dev_attr.attr,
> + NULL,
> +};
> +
> +static struct attribute *ina226_attributes[] = {
> &iio_dev_attr_in_allow_async_readout.dev_attr.attr,
> - &iio_const_attr_integration_time_available.dev_attr.attr,
> + &iio_const_attr_ina226_integration_time_available.dev_attr.attr,
> &iio_dev_attr_in_shunt_resistor.dev_attr.attr,
> NULL,
> };
>
> -static const struct attribute_group ina2xx_attribute_group = {
> - .attrs = ina2xx_attributes,
> +static const struct attribute_group ina219_attribute_group = {
> + .attrs = ina219_attributes,
> };
>
> -static const struct iio_info ina2xx_info = {
> +static const struct attribute_group ina226_attribute_group = {
> + .attrs = ina226_attributes,
> +};
> +
> +static const struct iio_info ina219_info = {
> + .driver_module = THIS_MODULE,
> + .attrs = &ina219_attribute_group,
> + .read_raw = ina2xx_read_raw,
> + .write_raw = ina2xx_write_raw,
> + .debugfs_reg_access = ina2xx_debug_reg,
> +};
> +
> +static const struct iio_info ina226_info = {
> .driver_module = THIS_MODULE,
> - .attrs = &ina2xx_attribute_group,
> + .attrs = &ina226_attribute_group,
> .read_raw = ina2xx_read_raw,
> .write_raw = ina2xx_write_raw,
> .debugfs_reg_access = ina2xx_debug_reg,
> @@ -686,6 +836,10 @@ static int ina2xx_probe(struct i2c_client *client,
> 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);
> + } else {
> + chip->avg = 1;
> + ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
> + ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
> }
>
> ret = ina2xx_init(chip, val);
> @@ -697,10 +851,16 @@ static int ina2xx_probe(struct i2c_client *client,
> indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
> indio_dev->dev.parent = &client->dev;
> indio_dev->dev.of_node = client->dev.of_node;
> - indio_dev->channels = ina2xx_channels;
> - indio_dev->num_channels = ARRAY_SIZE(ina2xx_channels);
> + if (id->driver_data == ina226) {
> + indio_dev->channels = ina226_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ina226_channels);
> + indio_dev->info = &ina226_info;
> + } else {
> + indio_dev->channels = ina219_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ina219_channels);
> + indio_dev->info = &ina219_info;
> + }
> indio_dev->name = id->name;
> - indio_dev->info = &ina2xx_info;
> indio_dev->setup_ops = &ina2xx_setup_ops;
>
> buffer = devm_iio_kfifo_allocate(&indio_dev->dev);