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SubjectRe: [PATCH 1/1] hwmon: Add support for INA3221 Triple Current/Voltage Monitors
From
Date
On 04/11/2016 01:50 PM, Andrew F. Davis wrote:
> Add support for the the INA3221 26v capable, Triple channel,
> Bi-Directional, Zero-Drift, Low-/High-Side, Current/Voltage Monitor
> with I2C interface.
>
> Signed-off-by: Andrew F. Davis <afd@ti.com>
> ---
> Documentation/hwmon/ina3221 | 32 ++++
> drivers/hwmon/Kconfig | 11 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/ina3221.c | 398 ++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 442 insertions(+)
> create mode 100644 Documentation/hwmon/ina3221
> create mode 100644 drivers/hwmon/ina3221.c
>
> diff --git a/Documentation/hwmon/ina3221 b/Documentation/hwmon/ina3221
> new file mode 100644
> index 0000000..3de3814
> --- /dev/null
> +++ b/Documentation/hwmon/ina3221
> @@ -0,0 +1,32 @@
> +Kernel driver ina3221
> +=====================
> +
> +Supported chips:
> + * Texas Instruments INA3221
> + Prefix: 'ina3221'
> + Addresses: I2C 0x40 - 0x43
> + Datasheet: Publicly available at the Texas Instruments website
> + http://www.ti.com/
> +
> +Author: Andrew F. Davis <afd@ti.com>
> +
> +Description
> +-----------
> +
> +The Texas Instruments INA3221 monitors voltage, current, and power on the high
> +side of up to three D.C. power supplies. The INA3221 monitors both shunt drop
> +and supply voltage, with programmable conversion times and averaging, current
> +and power are calculated host-side from these.
> +
> +Sysfs entries
> +-------------
> +
> +in[012]_input Bus voltages(mV) for channels 1, 2, and 3 respectively
> +in[345]_input Shunt voltages(mV) for channels 1, 2, and 3 respectively
> +curr[012]_input Current(mA) measurement for channels 1, 2, and 3 respectively

Numbering for currents is [123], not [012].

> +power[012]_input Power(uW) measurement for channels 1, 2, and 3 respectively

hwmon only reports what is there, and doesn't do calculations. The chip doesn't report
the power, so please drop the power attributes.

> +shunt[012]_resistor Shunt resistance(uOhm) for channels 1, 2, and 3 respectively

This should be a backup, if neither devicetree nor platform data are provided,
not a primary means to provide the shunt resistor value. Also, there should be a default,
to make sure the driver provides useful data even if nothing is configured.
See ina2xx.c for an example.

> +critical[012]_alarm Critical alert voltage(mV) setting, activated when the
> + respective shunt voltage is above this value.
> +warning[012]_alarm Warning alert voltage(mV) setting, activated when the
> + respective shunt voltage average is above this value.

Alarm attributes report the alarm status, not voltages. Use in[012]_max and
in[012]_crit attributes to set the limits. Report the alarm status with
in[012]_max_alarm and in[012]_crit_alarm (from register 0x0f, bit 9-7 and
5-3).

> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 5c2d13a..de08242 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1503,6 +1503,17 @@ config SENSORS_INA2XX
> This driver can also be built as a module. If so, the module
> will be called ina2xx.
>
> +config SENSORS_INA3221
> + tristate "Texas Instruments INA3221 Triple Power Monitor"
> + depends on I2C
> + select REGMAP_I2C
> + help
> + If you say yes here you get support for the TI INA3221 Triple Power
> + Monitor.
> +
> + This driver can also be built as a module. If so, the module
> + will be called ina3221.
> +
> config SENSORS_TC74
> tristate "Microchip TC74"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 58cc3ac..83e8ab0 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_SENSORS_IBMPOWERNV)+= ibmpowernv.o
> obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o
> obj-$(CONFIG_SENSORS_INA209) += ina209.o
> obj-$(CONFIG_SENSORS_INA2XX) += ina2xx.o
> +obj-$(CONFIG_SENSORS_INA3221) += ina3221.o
> obj-$(CONFIG_SENSORS_IT87) += it87.o
> obj-$(CONFIG_SENSORS_JC42) += jc42.o
> obj-$(CONFIG_SENSORS_JZ4740) += jz4740-hwmon.o
> diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
> new file mode 100644
> index 0000000..763e23b
> --- /dev/null
> +++ b/drivers/hwmon/ina3221.c
> @@ -0,0 +1,398 @@
> +/*
> + * INA3221 Triple Current/Voltage Monitor
> + *
> + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
> + * Andrew F. Davis <afd@ti.com>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +
> +#define INA3221_DRIVER_NAME "ina3221"
> +
> +#define INA3221_CONFIG 0x00
> +#define INA3221_SHUNT1 0x01
> +#define INA3221_BUS1 0x02
> +#define INA3221_SHUNT2 0x03
> +#define INA3221_BUS2 0x04
> +#define INA3221_SHUNT3 0x05
> +#define INA3221_BUS3 0x06
> +#define INA3221_CRIT1 0x07
> +#define INA3221_WARN1 0x08
> +#define INA3221_CRIT2 0x09
> +#define INA3221_WARN2 0x0a
> +#define INA3221_CRIT3 0x0b
> +#define INA3221_WARN3 0x0c
> +#define INA3221_SHUNT_SUM 0x0d
> +#define INA3221_SHUNT_SUM_LIMIT 0x0e
> +#define INA3221_MASK_ENABLE 0x0f
> +#define INA3221_POWERV_HLIMIT 0x10
> +#define INA3221_POWERV_LLIMIT 0x11
> +
> +#define INA3221_CONFIG_MODE_SHUNT BIT(1)
> +#define INA3221_CONFIG_MODE_BUS BIT(2)
> +#define INA3221_CONFIG_MODE_CONTINUOUS BIT(3)
> +
> +enum ina3221_fields {
> + /* Configuration */
> + F_MODE, F_SHUNT_CT, F_BUS_CT, F_AVG,
> + F_CHAN3_EN, F_CHAN2_EN, F_CHAN1_EN, F_RST,
> +
> + /* sentinel */
> + F_MAX_FIELDS
> +};
> +
> +static const struct reg_field ina3221_reg_fields[] = {
> + [F_MODE] = REG_FIELD(INA3221_CONFIG, 0, 2),
> + [F_SHUNT_CT] = REG_FIELD(INA3221_CONFIG, 3, 5),
> + [F_BUS_CT] = REG_FIELD(INA3221_CONFIG, 6, 8),
> + [F_AVG] = REG_FIELD(INA3221_CONFIG, 9, 11),
> + [F_CHAN3_EN] = REG_FIELD(INA3221_CONFIG, 12, 12),
> + [F_CHAN2_EN] = REG_FIELD(INA3221_CONFIG, 13, 13),
> + [F_CHAN1_EN] = REG_FIELD(INA3221_CONFIG, 14, 14),
> + [F_RST] = REG_FIELD(INA3221_CONFIG, 15, 15),
> +};
> +
> +enum ina3221_channels {
> + INA3221_CHANNEL1,
> + INA3221_CHANNEL2,
> + INA3221_CHANNEL3,
> + INA3221_NUM_CHANNELS
> +};
> +
> +static const int shunt_registers[] = {
> + [INA3221_CHANNEL1] = INA3221_SHUNT1,
> + [INA3221_CHANNEL2] = INA3221_SHUNT2,
> + [INA3221_CHANNEL3] = INA3221_SHUNT3,
> +};
> +
> +static const int bus_registers[] = {
> + [INA3221_CHANNEL1] = INA3221_BUS1,
> + [INA3221_CHANNEL2] = INA3221_BUS2,
> + [INA3221_CHANNEL3] = INA3221_BUS3,
> +};
> +
> +/**
> + * struct ina3221_data - device specific information
> + * @dev: Device structure
> + * @regmap: Register map of the device
> + * @fields: Register fields of the device
> + */
> +struct ina3221_data {
> + struct device *dev;
> + struct regmap *regmap;
> + struct regmap_field *fields[F_MAX_FIELDS];
> + unsigned int shunt_resistors[INA3221_NUM_CHANNELS];
> +};
> +
> +static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
> + unsigned int *val)
> +{
> + unsigned int regval;
> + int ret;
> +
> + ret = regmap_read(ina->regmap, reg, &regval);
> + if (ret)
> + return ret;
> +
> + *val = sign_extend32(regval >> 3, 12);
> +
> + return 0;
> +}
> +
> +static ssize_t ina3221_show_voltage(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int reg = sd_attr->index;
> + int val, voltage_mv, ret;
> +
> + ret = ina3221_read_value(ina, reg, &val);
> + if (ret)
> + return ret;
> +
> + if (reg == INA3221_BUS1 ||
> + reg == INA3221_BUS2 ||
> + reg == INA3221_BUS3)
> + voltage_mv = val * 8;
> + else
> + voltage_mv = DIV_ROUND_CLOSEST(val * 40, 1000);
> +
> + return snprintf(buf, PAGE_SIZE, "%d\n", voltage_mv);
> +}
> +
> +static ssize_t ina3221_set_voltage(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int reg = sd_attr->index;
> + int val, ret;
> +
> + ret = kstrtoint(buf, 10, &val);
> + if (ret)
> + return ret;
> +
Please clamp the value to valid voltage range.

> + val = DIV_ROUND_CLOSEST(val, 40000) << 3;
> +
> + ret = regmap_write(ina->regmap, reg, val);
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static ssize_t ina3221_show_current(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int channel = sd_attr->index;
> + unsigned int shunt_reg, resistance_uo;
> + int val, current_ma, shunt_voltage_mv, ret;
> +
> + shunt_reg = shunt_registers[channel];
> + resistance_uo = ina->shunt_resistors[channel];
> + if (resistance_uo == 0) {
> + current_ma = 0;
> + goto resistance_is_futile;

Please no funny label names. Also, just make sure that shunt_resistors[]
is never 0 to avoid having to check the value here.

> + }
> +
> + ret = ina3221_read_value(ina, shunt_reg, &val);
> + if (ret)
> + return ret;
> + shunt_voltage_mv = val * 40000;
> +
> + current_ma = DIV_ROUND_CLOSEST(shunt_voltage_mv, resistance_uo);
> +resistance_is_futile:
> + return snprintf(buf, PAGE_SIZE, "%d\n", current_ma);
> +}
> +
> +static ssize_t ina3221_show_power(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int channel = sd_attr->index;
> + unsigned int shunt_reg, bus_reg, resistance_uo;
> + int val, power_uw, current_ma, shunt_voltage_mv, bus_voltage_mv, ret;
> +
> + shunt_reg = shunt_registers[channel];
> + bus_reg = bus_registers[channel];
> + resistance_uo = ina->shunt_resistors[channel];
> + if (resistance_uo == 0) {
> + power_uw = 0;
> + goto sorry_i_couldnt_resist;
> + }
> +
> + ret = ina3221_read_value(ina, shunt_reg, &val);
> + if (ret)
> + return ret;
> + shunt_voltage_mv = val * 40000;
> +
> + current_ma = DIV_ROUND_CLOSEST(shunt_voltage_mv, resistance_uo);
> +
> + ret = ina3221_read_value(ina, bus_reg, &val);
> + if (ret)
> + return ret;
> + bus_voltage_mv = val * 8;
> +
> + power_uw = current_ma * bus_voltage_mv;
> +sorry_i_couldnt_resist:
> + return snprintf(buf, PAGE_SIZE, "%d\n", power_uw);
> +}
> +
> +static ssize_t ina3221_show_shunt(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int channel = sd_attr->index;
> + unsigned int resistance_uo;
> +
> + resistance_uo = ina->shunt_resistors[channel];
> +
> + return snprintf(buf, PAGE_SIZE, "%d\n", resistance_uo);
> +}
> +
> +static ssize_t ina3221_set_shunt(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> + struct ina3221_data *ina = dev_get_drvdata(dev);
> + unsigned int channel = sd_attr->index;
> + int ret;
> +
> + ret = kstrtouint(buf, 10, &ina->shunt_resistors[channel]);
> + if (ret)
> + return ret;
> +
Please don't blindly accept values here. Wrong values should be rejected.
See ina2xx.c for an example.

> + return count;
> +}
> +
> +/* bus voltages */
> +static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_BUS1);
> +static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_BUS2);
> +static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_BUS3);
> +
> +/* shunt voltages */
> +static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_SHUNT1);
> +static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_SHUNT2);
> +static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ina3221_show_voltage, NULL, INA3221_SHUNT3);
> +
> +/* calculated current */
> +static SENSOR_DEVICE_ATTR(curr0_input, S_IRUGO, ina3221_show_current, NULL, INA3221_CHANNEL1);
> +static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina3221_show_current, NULL, INA3221_CHANNEL2);
> +static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ina3221_show_current, NULL, INA3221_CHANNEL3);
> +
> +/* calculated power */
> +static SENSOR_DEVICE_ATTR(power0_input, S_IRUGO, ina3221_show_power, NULL, INA3221_CHANNEL1);
> +static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina3221_show_power, NULL, INA3221_CHANNEL2);
> +static SENSOR_DEVICE_ATTR(power2_input, S_IRUGO, ina3221_show_power, NULL, INA3221_CHANNEL3);
> +
> +/* shunt resistance */
> +static SENSOR_DEVICE_ATTR(shunt0_resistor, (S_IRUGO | S_IWUSR), ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL1);
> +static SENSOR_DEVICE_ATTR(shunt1_resistor, (S_IRUGO | S_IWUSR), ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL2);
> +static SENSOR_DEVICE_ATTR(shunt2_resistor, (S_IRUGO | S_IWUSR), ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL3);
> +
> +/* critical alert */
> +static SENSOR_DEVICE_ATTR(critical0_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_CRIT1);
> +static SENSOR_DEVICE_ATTR(critical1_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_CRIT2);
> +static SENSOR_DEVICE_ATTR(critical2_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_CRIT3);
> +
> +/* warning alert */
> +static SENSOR_DEVICE_ATTR(warning0_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_WARN1);
> +static SENSOR_DEVICE_ATTR(warning1_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_WARN2);
> +static SENSOR_DEVICE_ATTR(warning2_alarm, (S_IRUGO | S_IWUSR), ina3221_show_voltage, ina3221_set_voltage, INA3221_WARN3);
> +
> +static struct attribute *ina3221_attrs[] = {
> + /* channel 1 */
> + &sensor_dev_attr_in0_input.dev_attr.attr,
> + &sensor_dev_attr_curr0_input.dev_attr.attr,
> + &sensor_dev_attr_power0_input.dev_attr.attr,
> + &sensor_dev_attr_shunt0_resistor.dev_attr.attr,
> + &sensor_dev_attr_critical0_alarm.dev_attr.attr,
> + &sensor_dev_attr_warning0_alarm.dev_attr.attr,
> + &sensor_dev_attr_in3_input.dev_attr.attr,
> +
> + /* channel 2 */
> + &sensor_dev_attr_in1_input.dev_attr.attr,
> + &sensor_dev_attr_curr1_input.dev_attr.attr,
> + &sensor_dev_attr_power1_input.dev_attr.attr,
> + &sensor_dev_attr_shunt1_resistor.dev_attr.attr,
> + &sensor_dev_attr_critical1_alarm.dev_attr.attr,
> + &sensor_dev_attr_warning1_alarm.dev_attr.attr,
> + &sensor_dev_attr_in4_input.dev_attr.attr,
> +
> + /* channel 3 */
> + &sensor_dev_attr_in2_input.dev_attr.attr,
> + &sensor_dev_attr_curr2_input.dev_attr.attr,
> + &sensor_dev_attr_power2_input.dev_attr.attr,
> + &sensor_dev_attr_shunt2_resistor.dev_attr.attr,
> + &sensor_dev_attr_critical2_alarm.dev_attr.attr,
> + &sensor_dev_attr_warning2_alarm.dev_attr.attr,
> + &sensor_dev_attr_in5_input.dev_attr.attr,
> +
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(ina3221);
> +
> +static const struct regmap_range ina3221_yes_ranges[] = {
> + regmap_reg_range(INA3221_SHUNT1, INA3221_BUS3),
> + regmap_reg_range(INA3221_MASK_ENABLE, INA3221_MASK_ENABLE),
> +};
> +
> +static const struct regmap_access_table ina3221_volatile_table = {
> + .yes_ranges = ina3221_yes_ranges,
> + .n_yes_ranges = ARRAY_SIZE(ina3221_yes_ranges),
> +};
> +
> +static const struct regmap_config ina3221_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 16,
> +
> + .cache_type = REGCACHE_RBTREE,
> + .volatile_table = &ina3221_volatile_table,
> +};
> +
> +static int ina3221_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct ina3221_data *ina;
> + struct device *hwmon_dev;
> + int i, ret;
> +
> + ina = devm_kzalloc(&client->dev, sizeof(*ina), GFP_KERNEL);
> + if (!ina)
> + return -ENOMEM;
> + i2c_set_clientdata(client, ina);
> +
> + ina->dev = &client->dev;
> +
> + ina->regmap = devm_regmap_init_i2c(client, &ina3221_regmap_config);
> + if (IS_ERR(ina->regmap)) {
> + dev_err(ina->dev, "Unable to allocate register map\n");
> + return PTR_ERR(ina->regmap);
> + }
> +
> + for (i = 0; i < F_MAX_FIELDS; i++) {
> + ina->fields[i] = devm_regmap_field_alloc(ina->dev,
> + ina->regmap,
> + ina3221_reg_fields[i]);
> + if (IS_ERR(ina->fields[i])) {
> + dev_err(ina->dev, "Unable to allocate regmap fields\n");
> + return PTR_ERR(ina->fields[i]);
> + }
> + }
> +
> + ret = regmap_field_write(ina->fields[F_RST], true);
> + if (ret) {
> + dev_err(ina->dev, "Unable to reset device\n");
> + return ret;
> + }
> +
> + hwmon_dev = devm_hwmon_device_register_with_groups(ina->dev,
> + client->name,
> + ina, ina3221_groups);
> + if (IS_ERR(hwmon_dev)) {
> + dev_err(ina->dev, "Unable register hwmon device\n");
> + return PTR_ERR(hwmon_dev);
> + }
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id ina3221_ids[] = {
> + { "ina3221", 0 },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(i2c, ina3221_ids);
> +
> +static struct i2c_driver ina3221_i2c_driver = {
> + .driver = {
> + .name = INA3221_DRIVER_NAME,
> + },
> + .probe = ina3221_probe,
> + .id_table = ina3221_ids,
> +};
> +module_i2c_driver(ina3221_i2c_driver);
> +
> +MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
> +MODULE_DESCRIPTION("Texas Instruments INA3221 HWMon Driver");
> +MODULE_LICENSE("GPL v2");
>

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