[RFC v2 1/2] iio: ina2xx: add direct IO support for TI INA2xx Power Monitors

From: Marc Titinger
Date: Thu Nov 12 2015 - 07:57:52 EST

Basic support or direct IO raw read, with averaging attribute.
Values are RAW, INT_PLUS_MICRO (Volt/Ampere/Watt).

Output of iio_info:

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
attr 2: in_sampling_frequency value: 455

Tested with ina226, on BeagleBoneBlack.

Datasheet: http://www.ti.com/lit/gpn/ina226

Signed-off-by: Marc Titinger <mtitinger@xxxxxxxxxxxx>
---

v2 of series https://lkml.org/lkml/2015/11/10/370 :

- squash patches adding SAMPL_FREQ and debugfs interface
- add regmap is_volatile and is_writeable callbacks
- fix Kconfig deps and alphabetical sorting
- simplification: use devm_iio_device_register

---

drivers/iio/adc/Kconfig | 9 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ina2xx-iio.c | 472 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 482 insertions(+)
create mode 100644 drivers/iio/adc/ina2xx-iio.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index eb0cd89..087e5bd 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -170,6 +170,15 @@ config EXYNOS_ADC
of SoCs for drivers such as the touchscreen and hwmon to use to share
this resource.

+config INA2XX_IIO
+ tristate "Texas Instruments INA2xx Power Monitors IIO driver"
+ depends on I2C
+ select REGMAP_I2C
+ 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 LP8788_ADC
tristate "LP8788 ADC driver"
depends on MFD_LP8788
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index a096210..74e4341 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
+obj-$(CONFIG_INA2XX_IIO) += ina2xx-iio.o
obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX1363) += max1363.o
diff --git a/drivers/iio/adc/ina2xx-iio.c b/drivers/iio/adc/ina2xx-iio.c
new file mode 100644
index 0000000..28b7919
--- /dev/null
+++ b/drivers/iio/adc/ina2xx-iio.c
@@ -0,0 +1,472 @@
+/*
+ * 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.
+ *
+ * IIO driver for INA219-220-226-230-231
+ *
+ * Configurable 7-bit I2C slave address from 0x40 to 0x4F
+ */
+#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>
+
+/*
+ * 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 INA226_DEFAULT_FREQ 454
+
+#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)
+
+#define INA226_SFREQ_RD_MASK 0x01f8
+
+
+static bool ina2xx_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+ return (reg == INA2XX_CONFIG)
+ || (reg == INA2XX_CALIBRATION);
+}
+
+static bool ina2xx_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return (reg != INA2XX_CONFIG);
+}
+
+static struct regmap_config ina2xx_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+
+ .writeable_reg = ina2xx_is_writeable_reg,
+ .volatile_reg = ina2xx_is_volatile_reg,
+};
+
+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);
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = chip->freq;
+ return IIO_VAL_INT;
+
+ 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;
+}
+
+/*
+ * Conversion times in uS
+ */
+static const int ina226_conv_time_tab[] = { 140, 204, 332, 588, 1100,
+ 2116, 4156, 8244};
+
+static unsigned int ina226_set_frequency(struct ina2xx_chip_info *chip,
+ unsigned int val,
+ unsigned int *config)
+{
+ int bits;
+
+ if (val > 3550 || val < 50)
+ return -EINVAL;
+
+ /* integration time in uS, for both voltage channels */
+ val = DIV_ROUND_CLOSEST(1000000, 2 * val);
+
+ bits = find_closest(val, ina226_conv_time_tab,
+ ARRAY_SIZE(ina226_conv_time_tab));
+
+ chip->period_us = 2 * ina226_conv_time_tab[bits];
+
+ chip->freq = DIV_ROUND_CLOSEST(1000000, chip->period_us);
+
+ *config &= ~INA226_SFREQ_RD_MASK;
+ *config |= (bits << 3) | (bits << 6);
+
+ 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;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+
+ ret = ina226_set_frequency(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_SAMP_FREQ) | \
+ 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 int ina2xx_debug_reg(struct iio_dev *indio_dev,
+ unsigned reg, unsigned writeval, unsigned *readval)
+{
+ struct ina2xx_chip_info *chip = iio_priv(indio_dev);
+
+ if (!readval)
+ return regmap_write(chip->regmap, reg, writeval);
+
+ return regmap_read(chip->regmap, reg, readval);
+}
+
+static const struct iio_info ina2xx_info = {
+ .debugfs_reg_access = &ina2xx_debug_reg,
+ .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);
+ ina226_set_frequency(chip, INA226_DEFAULT_FREQ, &val);
+ }
+
+ ret = ina2xx_init(chip, val);
+ if (ret < 0) {
+ dev_err(&client->dev, "error configuring the device: %d\n",
+ ret);
+ return -ENODEV;
+ }
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+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,
+ .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");
--
1.9.1

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