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

[Jonathan Cameron]

On Wed, 24 May 2017 02:09:06 +0200
Stefan BrÃns <stefan.bruens@xxxxxxxxxxxxxx> 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 BrÃns <stefan.bruens@xxxxxxxxxxxxxx>
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);