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Message-ID: <81f81a0af7dd420db51f97d9be4dcbad@rwthex-w2-b.rwth-ad.de>
Date: Wed, 12 Apr 2017 05:01:40 +0200
From: Stefan Brüns <stefan.bruens@...h-aachen.de>
To: <linux-iio@...r.kernel.org>
CC: <linux-kernel@...r.kernel.org>,
Jonathan Cameron <jic23@...nel.org>,
Hartmut Knaack <knaack.h@....de>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Stefan Brüns <stefan.bruens@...h-aachen.de>
Subject: [PATCH 2/2] iio: adc: Allow setting Shunt Voltage PGA gain and Bus Voltage range
Reducing shunt and bus voltage range improves the accuracy, so allow
altering the default settings.
Signed-off-by: Stefan Brüns <stefan.bruens@...h-aachen.de>
---
drivers/iio/adc/ina2xx-adc.c | 165 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 164 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
index d1678f886297..856409ecceb3 100644
--- a/drivers/iio/adc/ina2xx-adc.c
+++ b/drivers/iio/adc/ina2xx-adc.c
@@ -47,8 +47,10 @@
#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 32
+#define INA219_DEFAULT_PGA 125 /* 1000/8 */
#define INA226_CONFIG_DEFAULT 0x4327
#define INA226_DEFAULT_AVG 4
#define INA226_DEFAULT_IT 1110
@@ -61,6 +63,14 @@
*/
#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)
@@ -125,6 +135,8 @@ 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;
};
@@ -351,6 +363,44 @@ static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
return 0;
}
+static int ina219_set_vbus_range(struct ina2xx_chip_info *chip,
+ unsigned int range,
+ unsigned int *config)
+{
+ if (range != 16 && range != 32)
+ return -EINVAL;
+
+ chip->range_vbus = range;
+
+ *config &= ~INA219_BRNG_MASK;
+ *config |= INA219_SHIFT_BRNG(range == 32 ? 1 : 0) & INA219_BRNG_MASK;
+
+ return 0;
+}
+
+static const int ina219_vshunt_gain_tab[] = { 125, 250, 500, 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_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
@@ -485,6 +535,92 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
return len;
}
+static ssize_t ina219_bus_voltage_range_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->range_vbus);
+}
+
+static ssize_t ina219_bus_voltage_range_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
+ unsigned long val;
+ unsigned int config, tmp;
+ int ret;
+
+ ret = kstrtoul((const char *) buf, 10, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&chip->state_lock);
+
+ ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config);
+ if (ret)
+ goto err;
+
+ tmp = config;
+
+ ret = ina219_set_vbus_range(chip, val, &config);
+
+ if (!ret && (tmp != config))
+ ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
+
+ if (!ret)
+ ret = len;
+err:
+ mutex_unlock(&chip->state_lock);
+
+ return ret;
+}
+
+static ssize_t ina219_shunt_voltage_gain_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
+ int vals[2] = { chip->pga_gain_vshunt, 1000 };
+
+ return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals);
+}
+
+static ssize_t ina219_shunt_voltage_gain_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
+ unsigned int config, tmp;
+ int val, val_fract, ret;
+
+ ret = iio_str_to_fixpoint(buf, 100, &val, &val_fract);
+ if (ret)
+ return ret;
+
+ mutex_lock(&chip->state_lock);
+
+ ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config);
+ if (ret)
+ goto err;
+
+ tmp = config;
+
+ ret = ina219_set_vshunt_pga_gain(chip, val * 1000 + val_fract, &config);
+
+ if (!ret && (tmp != config))
+ ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
+
+ if (!ret)
+ ret = len;
+err:
+ mutex_unlock(&chip->state_lock);
+
+ return ret;
+}
+
#define INA2XX_CHAN(_type, _index, _address) { \
.type = (_type), \
.address = (_address), \
@@ -698,6 +834,15 @@ 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");
+/* INA219/220 Bus voltage range */
+static IIO_CONST_ATTR_NAMED(ina219_bus_voltage_range_available,
+ in_bus_voltage_range_available,
+ "16 32");
+
+/* INA219/220 Shunt voltage PGA gain */
+static IIO_CONST_ATTR_NAMED(ina219_shunt_voltage_gain_available,
+ in_shunt_voltage_gain_available,
+ "0.125 0.25 0.5 1");
static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR,
ina2xx_allow_async_readout_show,
@@ -707,9 +852,25 @@ static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO | S_IWUSR,
ina2xx_shunt_resistor_show,
ina2xx_shunt_resistor_store, 0);
+static IIO_DEVICE_ATTR_NAMED(ina219_bus_voltage_range,
+ in_bus_voltage_range,
+ S_IRUGO | S_IWUSR,
+ ina219_bus_voltage_range_show,
+ ina219_bus_voltage_range_store, 0);
+
+static IIO_DEVICE_ATTR_NAMED(ina219_shunt_voltage_gain,
+ in_shunt_voltage_gain,
+ S_IRUGO | S_IWUSR,
+ ina219_shunt_voltage_gain_show,
+ ina219_shunt_voltage_gain_store, 0);
+
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_ina219_bus_voltage_range.dev_attr.attr,
+ &iio_const_attr_ina219_bus_voltage_range_available.dev_attr.attr,
+ &iio_dev_attr_ina219_shunt_voltage_gain.dev_attr.attr,
+ &iio_const_attr_ina219_shunt_voltage_gain_available.dev_attr.attr,
&iio_dev_attr_in_shunt_resistor.dev_attr.attr,
NULL,
};
@@ -809,6 +970,8 @@ 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(chip, INA219_DEFAULT_BRNG, &val);
+ ina219_set_vshunt_pga_gain(chip, INA219_DEFAULT_PGA, &val);
}
ret = ina2xx_init(chip, val);
--
2.12.0
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