diff mbox

[v2,3/3] iio: adc: ina2xx: Allow setting Shunt Voltage PGA gain and Bus Voltage range

Message ID 0a100ee0-13c7-4865-a9c1-ede3204c0e59@rwthex-w2-a.rwth-ad.de (mailing list archive)
State New, archived
Headers show

Commit Message

Stefan Brüns Oct. 28, 2017, 9:12 p.m. UTC 
Reducing shunt and bus voltage range improves the accuracy, so allow
altering the default settings.

Both settings are exposed as gain values. While for the shunt voltage
this is straightforward, the bus range settings of 32V (default) and 16V
are mapped to gain values of 1 resp. 2, to provide a uniform API to
userspace.

As the gain settings are incorporated into the raw values by the sensor
itself, adjusting of the scale attributes is not necessary.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

---

Changes in v2:
- Fix conversion for shunt gain, function expects milli, not micro

 drivers/iio/adc/ina2xx-adc.c | 111 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 108 insertions(+), 3 deletions(-)

Comments

Jonathan Cameron Nov. 19, 2017, 4:16 p.m. UTC | #1 
On Sat, 28 Oct 2017 23:12:48 +0200
Stefan Brüns <stefan.bruens@rwth-aachen.de> wrote:

> Reducing shunt and bus voltage range improves the accuracy, so allow
> altering the default settings.
> 
> Both settings are exposed as gain values. While for the shunt voltage
> this is straightforward, the bus range settings of 32V (default) and 16V
> are mapped to gain values of 1 resp. 2, to provide a uniform API to
> userspace.
> 
> As the gain settings are incorporated into the raw values by the sensor
> itself, adjusting of the scale attributes is not necessary.
> 
> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Applied to the togreg branch of iio.git and pushed out as testing.

thanks,

Jonathan
> 
> ---
> 
> Changes in v2:
> - Fix conversion for shunt gain, function expects milli, not micro
> 
>  drivers/iio/adc/ina2xx-adc.c | 111 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 108 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> index c59843de3999..d05cb1b8efe6 100644
> --- a/drivers/iio/adc/ina2xx-adc.c
> +++ b/drivers/iio/adc/ina2xx-adc.c
> @@ -48,8 +48,10 @@
>  #define INA2XX_MAX_REGISTERS            8
>  
>  /* settings - depend on use case */
> -#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=8 */
> +#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=1/8, BRNG=32V */
>  #define INA219_DEFAULT_IT		532
> +#define INA219_DEFAULT_BRNG             1   /* 32V */
> +#define INA219_DEFAULT_PGA              125 /* 1000/8 */
>  #define INA226_CONFIG_DEFAULT           0x4327
>  #define INA226_DEFAULT_AVG              4
>  #define INA226_DEFAULT_IT		1110
> @@ -62,6 +64,14 @@
>   */
>  #define INA2XX_MODE_MASK	GENMASK(3, 0)
>  
> +/* Gain for VShunt: 1/8 (default), 1/4, 1/2, 1 */
> +#define INA219_PGA_MASK		GENMASK(12, 11)
> +#define INA219_SHIFT_PGA(val)	((val) << 11)
> +
> +/* VBus range: 32V (default), 16V */
> +#define INA219_BRNG_MASK	BIT(13)
> +#define INA219_SHIFT_BRNG(val)	((val) << 13)
> +
>  /* Averaging for VBus/VShunt/Power */
>  #define INA226_AVG_MASK		GENMASK(11, 9)
>  #define INA226_SHIFT_AVG(val)	((val) << 9)
> @@ -131,6 +141,8 @@ struct ina2xx_chip_info {
>  	int avg;
>  	int int_time_vbus; /* Bus voltage integration time uS */
>  	int int_time_vshunt; /* Shunt voltage integration time uS */
> +	int range_vbus; /* Bus voltage maximum in V */
> +	int pga_gain_vshunt; /* Shunt voltage PGA gain */
>  	bool allow_async_readout;
>  };
>  
> @@ -226,6 +238,18 @@ static int ina2xx_read_raw(struct iio_dev *indio_dev,
>  			*val = 1;
>  			return IIO_VAL_INT;
>  		}
> +
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		switch (chan->address) {
> +		case INA2XX_SHUNT_VOLTAGE:
> +			*val = chip->pga_gain_vshunt;
> +			*val2 = 1000;
> +			return IIO_VAL_FRACTIONAL;
> +
> +		case INA2XX_BUS_VOLTAGE:
> +			*val = chip->range_vbus == 32 ? 1 : 2;
> +			return IIO_VAL_INT;
> +		}
>  	}
>  
>  	return -EINVAL;
> @@ -360,6 +384,74 @@ static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
>  	return 0;
>  }
>  
> +static const int ina219_vbus_range_tab[] = { 1, 2 };
> +static int ina219_set_vbus_range_denom(struct ina2xx_chip_info *chip,
> +				       unsigned int range,
> +				       unsigned int *config)
> +{
> +	if (range == 1)
> +		chip->range_vbus = 32;
> +	else if (range == 2)
> +		chip->range_vbus = 16;
> +	else
> +		return -EINVAL;
> +
> +	*config &= ~INA219_BRNG_MASK;
> +	*config |= INA219_SHIFT_BRNG(range == 1 ? 1 : 0) & INA219_BRNG_MASK;
> +
> +	return 0;
> +}
> +
> +static const int ina219_vshunt_gain_tab[] = { 125, 250, 500, 1000 };
> +static const int ina219_vshunt_gain_frac[] = {
> +	125, 1000, 250, 1000, 500, 1000, 1000, 1000 };
> +
> +static int ina219_set_vshunt_pga_gain(struct ina2xx_chip_info *chip,
> +				      unsigned int gain,
> +				      unsigned int *config)
> +{
> +	int bits;
> +
> +	if (gain < 125 || gain > 1000)
> +		return -EINVAL;
> +
> +	bits = find_closest(gain, ina219_vshunt_gain_tab,
> +			    ARRAY_SIZE(ina219_vshunt_gain_tab));
> +
> +	chip->pga_gain_vshunt = ina219_vshunt_gain_tab[bits];
> +	bits = 3 - bits;
> +
> +	*config &= ~INA219_PGA_MASK;
> +	*config |= INA219_SHIFT_PGA(bits) & INA219_PGA_MASK;
> +
> +	return 0;
> +}
> +
> +static int ina2xx_read_avail(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     const int **vals, int *type, int *length,
> +			     long mask)
> +{
> +	switch (mask) {
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		switch (chan->address) {
> +		case INA2XX_SHUNT_VOLTAGE:
> +			*type = IIO_VAL_FRACTIONAL;
> +			*length = sizeof(ina219_vshunt_gain_frac) / sizeof(int);
> +			*vals = ina219_vshunt_gain_frac;
> +			return IIO_AVAIL_LIST;
> +
> +		case INA2XX_BUS_VOLTAGE:
> +			*type = IIO_VAL_INT;
> +			*length = sizeof(ina219_vbus_range_tab) / sizeof(int);
> +			*vals = ina219_vbus_range_tab;
> +			return IIO_AVAIL_LIST;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
>  static int ina2xx_write_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan,
>  			    int val, int val2, long mask)
> @@ -402,6 +494,14 @@ static int ina2xx_write_raw(struct iio_dev *indio_dev,
>  		}
>  		break;
>  
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		if (chan->address == INA2XX_SHUNT_VOLTAGE)
> +			ret = ina219_set_vshunt_pga_gain(chip, val * 1000 +
> +							 val2 / 1000, &tmp);
> +		else
> +			ret = ina219_set_vbus_range_denom(chip, val, &tmp);
> +		break;
> +
>  	default:
>  		ret = -EINVAL;
>  	}
> @@ -546,7 +646,10 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
>  	.channel = (_index), \
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>  			      BIT(IIO_CHAN_INFO_SCALE) | \
> -			      BIT(IIO_CHAN_INFO_INT_TIME), \
> +			      BIT(IIO_CHAN_INFO_INT_TIME) | \
> +			      BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
> +	.info_mask_separate_available = \
> +			      BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
>  	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
>  	.scan_index = (_index), \
>  	.scan_type = { \
> @@ -754,7 +857,6 @@ 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,
>  		       ina2xx_allow_async_readout_store, 0);
> @@ -789,6 +891,7 @@ static const struct iio_info ina219_info = {
>  	.driver_module = THIS_MODULE,
>  	.attrs = &ina219_attribute_group,
>  	.read_raw = ina2xx_read_raw,
> +	.read_avail = ina2xx_read_avail,
>  	.write_raw = ina2xx_write_raw,
>  	.debugfs_reg_access = ina2xx_debug_reg,
>  };
> @@ -870,6 +973,8 @@ static int ina2xx_probe(struct i2c_client *client,
>  		chip->avg = 1;
>  		ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
>  		ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
> +		ina219_set_vbus_range_denom(chip, INA219_DEFAULT_BRNG, &val);
> +		ina219_set_vshunt_pga_gain(chip, INA219_DEFAULT_PGA, &val);
>  	}
>  
>  	ret = ina2xx_init(chip, val);

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diff mbox

Patch

diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
index c59843de3999..d05cb1b8efe6 100644
--- a/drivers/iio/adc/ina2xx-adc.c
+++ b/drivers/iio/adc/ina2xx-adc.c
@@ -48,8 +48,10 @@ 
 #define INA2XX_MAX_REGISTERS            8
 
 /* settings - depend on use case */
-#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=8 */
+#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=1/8, BRNG=32V */
 #define INA219_DEFAULT_IT		532
+#define INA219_DEFAULT_BRNG             1   /* 32V */
+#define INA219_DEFAULT_PGA              125 /* 1000/8 */
 #define INA226_CONFIG_DEFAULT           0x4327
 #define INA226_DEFAULT_AVG              4
 #define INA226_DEFAULT_IT		1110
@@ -62,6 +64,14 @@ 
  */
 #define INA2XX_MODE_MASK	GENMASK(3, 0)
 
+/* Gain for VShunt: 1/8 (default), 1/4, 1/2, 1 */
+#define INA219_PGA_MASK		GENMASK(12, 11)
+#define INA219_SHIFT_PGA(val)	((val) << 11)
+
+/* VBus range: 32V (default), 16V */
+#define INA219_BRNG_MASK	BIT(13)
+#define INA219_SHIFT_BRNG(val)	((val) << 13)
+
 /* Averaging for VBus/VShunt/Power */
 #define INA226_AVG_MASK		GENMASK(11, 9)
 #define INA226_SHIFT_AVG(val)	((val) << 9)
@@ -131,6 +141,8 @@  struct ina2xx_chip_info {
 	int avg;
 	int int_time_vbus; /* Bus voltage integration time uS */
 	int int_time_vshunt; /* Shunt voltage integration time uS */
+	int range_vbus; /* Bus voltage maximum in V */
+	int pga_gain_vshunt; /* Shunt voltage PGA gain */
 	bool allow_async_readout;
 };
 
@@ -226,6 +238,18 @@  static int ina2xx_read_raw(struct iio_dev *indio_dev,
 			*val = 1;
 			return IIO_VAL_INT;
 		}
+
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		switch (chan->address) {
+		case INA2XX_SHUNT_VOLTAGE:
+			*val = chip->pga_gain_vshunt;
+			*val2 = 1000;
+			return IIO_VAL_FRACTIONAL;
+
+		case INA2XX_BUS_VOLTAGE:
+			*val = chip->range_vbus == 32 ? 1 : 2;
+			return IIO_VAL_INT;
+		}
 	}
 
 	return -EINVAL;
@@ -360,6 +384,74 @@  static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
 	return 0;
 }
 
+static const int ina219_vbus_range_tab[] = { 1, 2 };
+static int ina219_set_vbus_range_denom(struct ina2xx_chip_info *chip,
+				       unsigned int range,
+				       unsigned int *config)
+{
+	if (range == 1)
+		chip->range_vbus = 32;
+	else if (range == 2)
+		chip->range_vbus = 16;
+	else
+		return -EINVAL;
+
+	*config &= ~INA219_BRNG_MASK;
+	*config |= INA219_SHIFT_BRNG(range == 1 ? 1 : 0) & INA219_BRNG_MASK;
+
+	return 0;
+}
+
+static const int ina219_vshunt_gain_tab[] = { 125, 250, 500, 1000 };
+static const int ina219_vshunt_gain_frac[] = {
+	125, 1000, 250, 1000, 500, 1000, 1000, 1000 };
+
+static int ina219_set_vshunt_pga_gain(struct ina2xx_chip_info *chip,
+				      unsigned int gain,
+				      unsigned int *config)
+{
+	int bits;
+
+	if (gain < 125 || gain > 1000)
+		return -EINVAL;
+
+	bits = find_closest(gain, ina219_vshunt_gain_tab,
+			    ARRAY_SIZE(ina219_vshunt_gain_tab));
+
+	chip->pga_gain_vshunt = ina219_vshunt_gain_tab[bits];
+	bits = 3 - bits;
+
+	*config &= ~INA219_PGA_MASK;
+	*config |= INA219_SHIFT_PGA(bits) & INA219_PGA_MASK;
+
+	return 0;
+}
+
+static int ina2xx_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		switch (chan->address) {
+		case INA2XX_SHUNT_VOLTAGE:
+			*type = IIO_VAL_FRACTIONAL;
+			*length = sizeof(ina219_vshunt_gain_frac) / sizeof(int);
+			*vals = ina219_vshunt_gain_frac;
+			return IIO_AVAIL_LIST;
+
+		case INA2XX_BUS_VOLTAGE:
+			*type = IIO_VAL_INT;
+			*length = sizeof(ina219_vbus_range_tab) / sizeof(int);
+			*vals = ina219_vbus_range_tab;
+			return IIO_AVAIL_LIST;
+		}
+	}
+
+	return -EINVAL;
+}
+
 static int ina2xx_write_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int val, int val2, long mask)
@@ -402,6 +494,14 @@  static int ina2xx_write_raw(struct iio_dev *indio_dev,
 		}
 		break;
 
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		if (chan->address == INA2XX_SHUNT_VOLTAGE)
+			ret = ina219_set_vshunt_pga_gain(chip, val * 1000 +
+							 val2 / 1000, &tmp);
+		else
+			ret = ina219_set_vbus_range_denom(chip, val, &tmp);
+		break;
+
 	default:
 		ret = -EINVAL;
 	}
@@ -546,7 +646,10 @@  static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
 	.channel = (_index), \
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 			      BIT(IIO_CHAN_INFO_SCALE) | \
-			      BIT(IIO_CHAN_INFO_INT_TIME), \
+			      BIT(IIO_CHAN_INFO_INT_TIME) | \
+			      BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
+	.info_mask_separate_available = \
+			      BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
 	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
 	.scan_index = (_index), \
 	.scan_type = { \
@@ -754,7 +857,6 @@  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,
 		       ina2xx_allow_async_readout_store, 0);
@@ -789,6 +891,7 @@  static const struct iio_info ina219_info = {
 	.driver_module = THIS_MODULE,
 	.attrs = &ina219_attribute_group,
 	.read_raw = ina2xx_read_raw,
+	.read_avail = ina2xx_read_avail,
 	.write_raw = ina2xx_write_raw,
 	.debugfs_reg_access = ina2xx_debug_reg,
 };
@@ -870,6 +973,8 @@  static int ina2xx_probe(struct i2c_client *client,
 		chip->avg = 1;
 		ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
 		ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
+		ina219_set_vbus_range_denom(chip, INA219_DEFAULT_BRNG, &val);
+		ina219_set_vshunt_pga_gain(chip, INA219_DEFAULT_PGA, &val);
 	}
 
 	ret = ina2xx_init(chip, val);