diff options
Diffstat (limited to 'drivers/hwmon/ina238.c')
| -rw-r--r-- | drivers/hwmon/ina238.c | 644 |
1 files changed, 644 insertions, 0 deletions
diff --git a/drivers/hwmon/ina238.c b/drivers/hwmon/ina238.c new file mode 100644 index 000000000..50eb9c5e1 --- /dev/null +++ b/drivers/hwmon/ina238.c @@ -0,0 +1,644 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for Texas Instruments INA238 power monitor chip + * Datasheet: https://www.ti.com/product/ina238 + * + * Copyright (C) 2021 Nathan Rossi <nathan.rossi@digi.com> + */ + +#include <linux/err.h> +#include <linux/hwmon.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/regmap.h> + +#include <linux/platform_data/ina2xx.h> + +/* INA238 register definitions */ +#define INA238_CONFIG 0x0 +#define INA238_ADC_CONFIG 0x1 +#define INA238_SHUNT_CALIBRATION 0x2 +#define INA238_SHUNT_VOLTAGE 0x4 +#define INA238_BUS_VOLTAGE 0x5 +#define INA238_DIE_TEMP 0x6 +#define INA238_CURRENT 0x7 +#define INA238_POWER 0x8 +#define INA238_DIAG_ALERT 0xb +#define INA238_SHUNT_OVER_VOLTAGE 0xc +#define INA238_SHUNT_UNDER_VOLTAGE 0xd +#define INA238_BUS_OVER_VOLTAGE 0xe +#define INA238_BUS_UNDER_VOLTAGE 0xf +#define INA238_TEMP_LIMIT 0x10 +#define INA238_POWER_LIMIT 0x11 +#define INA238_DEVICE_ID 0x3f + +#define INA238_CONFIG_ADCRANGE BIT(4) + +#define INA238_DIAG_ALERT_TMPOL BIT(7) +#define INA238_DIAG_ALERT_SHNTOL BIT(6) +#define INA238_DIAG_ALERT_SHNTUL BIT(5) +#define INA238_DIAG_ALERT_BUSOL BIT(4) +#define INA238_DIAG_ALERT_BUSUL BIT(3) +#define INA238_DIAG_ALERT_POL BIT(2) + +#define INA238_REGISTERS 0x11 + +#define INA238_RSHUNT_DEFAULT 10000 /* uOhm */ + +/* Default configuration of device on reset. */ +#define INA238_CONFIG_DEFAULT 0 +/* 16 sample averaging, 1052us conversion time, continuous mode */ +#define INA238_ADC_CONFIG_DEFAULT 0xfb6a +/* Configure alerts to be based on averaged value (SLOWALERT) */ +#define INA238_DIAG_ALERT_DEFAULT 0x2000 +/* + * This driver uses a fixed calibration value in order to scale current/power + * based on a fixed shunt resistor value. This allows for conversion within the + * device to avoid integer limits whilst current/power accuracy is scaled + * relative to the shunt resistor value within the driver. This is similar to + * how the ina2xx driver handles current/power scaling. + * + * The end result of this is that increasing shunt values (from a fixed 20 mOhm + * shunt) increase the effective current/power accuracy whilst limiting the + * range and decreasing shunt values decrease the effective accuracy but + * increase the range. + * + * The value of the Current register is calculated given the following: + * Current (A) = (shunt voltage register * 5) * calibration / 81920 + * + * The maximum shunt voltage is 163.835 mV (0x7fff, ADC_RANGE = 0, gain = 4). + * With the maximum current value of 0x7fff and a fixed shunt value results in + * a calibration value of 16384 (0x4000). + * + * 0x7fff = (0x7fff * 5) * calibration / 81920 + * calibration = 0x4000 + * + * Equivalent calibration is applied for the Power register (maximum value for + * bus voltage is 102396.875 mV, 0x7fff), where the maximum power that can + * occur is ~16776192 uW (register value 0x147a8): + * + * This scaling means the resulting values for Current and Power registers need + * to be scaled by the difference between the fixed shunt resistor and the + * actual shunt resistor: + * + * shunt = 0x4000 / (819.2 * 10^6) / 0.001 = 20000 uOhms (with 1mA/lsb) + * + * Current (mA) = register value * 20000 / rshunt / 4 * gain + * Power (W) = 0.2 * register value * 20000 / rshunt / 4 * gain + */ +#define INA238_CALIBRATION_VALUE 16384 +#define INA238_FIXED_SHUNT 20000 + +#define INA238_SHUNT_VOLTAGE_LSB 5 /* 5 uV/lsb */ +#define INA238_BUS_VOLTAGE_LSB 3125 /* 3.125 mV/lsb */ +#define INA238_DIE_TEMP_LSB 125 /* 125 mC/lsb */ + +static struct regmap_config ina238_regmap_config = { + .max_register = INA238_REGISTERS, + .reg_bits = 8, + .val_bits = 16, +}; + +struct ina238_data { + struct i2c_client *client; + struct mutex config_lock; + struct regmap *regmap; + u32 rshunt; + int gain; +}; + +static int ina238_read_reg24(const struct i2c_client *client, u8 reg, u32 *val) +{ + u8 data[3]; + int err; + + /* 24-bit register read */ + err = i2c_smbus_read_i2c_block_data(client, reg, 3, data); + if (err < 0) + return err; + if (err != 3) + return -EIO; + *val = (data[0] << 16) | (data[1] << 8) | data[2]; + + return 0; +} + +static int ina238_read_in(struct device *dev, u32 attr, int channel, + long *val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int reg, mask; + int regval; + int err; + + switch (channel) { + case 0: + switch (attr) { + case hwmon_in_input: + reg = INA238_SHUNT_VOLTAGE; + break; + case hwmon_in_max: + reg = INA238_SHUNT_OVER_VOLTAGE; + break; + case hwmon_in_min: + reg = INA238_SHUNT_UNDER_VOLTAGE; + break; + case hwmon_in_max_alarm: + reg = INA238_DIAG_ALERT; + mask = INA238_DIAG_ALERT_SHNTOL; + break; + case hwmon_in_min_alarm: + reg = INA238_DIAG_ALERT; + mask = INA238_DIAG_ALERT_SHNTUL; + break; + default: + return -EOPNOTSUPP; + } + break; + case 1: + switch (attr) { + case hwmon_in_input: + reg = INA238_BUS_VOLTAGE; + break; + case hwmon_in_max: + reg = INA238_BUS_OVER_VOLTAGE; + break; + case hwmon_in_min: + reg = INA238_BUS_UNDER_VOLTAGE; + break; + case hwmon_in_max_alarm: + reg = INA238_DIAG_ALERT; + mask = INA238_DIAG_ALERT_BUSOL; + break; + case hwmon_in_min_alarm: + reg = INA238_DIAG_ALERT; + mask = INA238_DIAG_ALERT_BUSUL; + break; + default: + return -EOPNOTSUPP; + } + break; + default: + return -EOPNOTSUPP; + } + + err = regmap_read(data->regmap, reg, ®val); + if (err < 0) + return err; + + switch (attr) { + case hwmon_in_input: + case hwmon_in_max: + case hwmon_in_min: + /* signed register, value in mV */ + regval = (s16)regval; + if (channel == 0) + /* gain of 1 -> LSB / 4 */ + *val = (regval * INA238_SHUNT_VOLTAGE_LSB) / + (1000 * (4 - data->gain + 1)); + else + *val = (regval * INA238_BUS_VOLTAGE_LSB) / 1000; + break; + case hwmon_in_max_alarm: + case hwmon_in_min_alarm: + *val = !!(regval & mask); + break; + } + + return 0; +} + +static int ina238_write_in(struct device *dev, u32 attr, int channel, + long val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int regval; + + if (attr != hwmon_in_max && attr != hwmon_in_min) + return -EOPNOTSUPP; + + /* convert decimal to register value */ + switch (channel) { + case 0: + /* signed value, clamp to max range +/-163 mV */ + regval = clamp_val(val, -163, 163); + regval = (regval * 1000 * (4 - data->gain + 1)) / + INA238_SHUNT_VOLTAGE_LSB; + regval = clamp_val(regval, S16_MIN, S16_MAX); + + switch (attr) { + case hwmon_in_max: + return regmap_write(data->regmap, + INA238_SHUNT_OVER_VOLTAGE, regval); + case hwmon_in_min: + return regmap_write(data->regmap, + INA238_SHUNT_UNDER_VOLTAGE, regval); + default: + return -EOPNOTSUPP; + } + case 1: + /* signed value, positive values only. Clamp to max 102.396 V */ + regval = clamp_val(val, 0, 102396); + regval = (regval * 1000) / INA238_BUS_VOLTAGE_LSB; + regval = clamp_val(regval, 0, S16_MAX); + + switch (attr) { + case hwmon_in_max: + return regmap_write(data->regmap, + INA238_BUS_OVER_VOLTAGE, regval); + case hwmon_in_min: + return regmap_write(data->regmap, + INA238_BUS_UNDER_VOLTAGE, regval); + default: + return -EOPNOTSUPP; + } + default: + return -EOPNOTSUPP; + } +} + +static int ina238_read_current(struct device *dev, u32 attr, long *val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int regval; + int err; + + switch (attr) { + case hwmon_curr_input: + err = regmap_read(data->regmap, INA238_CURRENT, ®val); + if (err < 0) + return err; + + /* Signed register, fixed 1mA current lsb. result in mA */ + *val = div_s64((s16)regval * INA238_FIXED_SHUNT * data->gain, + data->rshunt * 4); + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int ina238_read_power(struct device *dev, u32 attr, long *val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + long long power; + int regval; + int err; + + switch (attr) { + case hwmon_power_input: + err = ina238_read_reg24(data->client, INA238_POWER, ®val); + if (err) + return err; + + /* Fixed 1mA lsb, scaled by 1000000 to have result in uW */ + power = div_u64(regval * 1000ULL * INA238_FIXED_SHUNT * + data->gain, 20 * data->rshunt); + /* Clamp value to maximum value of long */ + *val = clamp_val(power, 0, LONG_MAX); + break; + case hwmon_power_max: + err = regmap_read(data->regmap, INA238_POWER_LIMIT, ®val); + if (err) + return err; + + /* + * Truncated 24-bit compare register, lower 8-bits are + * truncated. Same conversion to/from uW as POWER register. + */ + power = div_u64((regval << 8) * 1000ULL * INA238_FIXED_SHUNT * + data->gain, 20 * data->rshunt); + /* Clamp value to maximum value of long */ + *val = clamp_val(power, 0, LONG_MAX); + break; + case hwmon_power_max_alarm: + err = regmap_read(data->regmap, INA238_DIAG_ALERT, ®val); + if (err) + return err; + + *val = !!(regval & INA238_DIAG_ALERT_POL); + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int ina238_write_power(struct device *dev, u32 attr, long val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + long regval; + + if (attr != hwmon_power_max) + return -EOPNOTSUPP; + + /* + * Unsigned postive values. Compared against the 24-bit power register, + * lower 8-bits are truncated. Same conversion to/from uW as POWER + * register. + */ + regval = clamp_val(val, 0, LONG_MAX); + regval = div_u64(val * 20ULL * data->rshunt, + 1000ULL * INA238_FIXED_SHUNT * data->gain); + regval = clamp_val(regval >> 8, 0, U16_MAX); + + return regmap_write(data->regmap, INA238_POWER_LIMIT, regval); +} + +static int ina238_read_temp(struct device *dev, u32 attr, long *val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int regval; + int err; + + switch (attr) { + case hwmon_temp_input: + err = regmap_read(data->regmap, INA238_DIE_TEMP, ®val); + if (err) + return err; + + /* Signed, bits 15-4 of register, result in mC */ + *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB; + break; + case hwmon_temp_max: + err = regmap_read(data->regmap, INA238_TEMP_LIMIT, ®val); + if (err) + return err; + + /* Signed, bits 15-4 of register, result in mC */ + *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB; + break; + case hwmon_temp_max_alarm: + err = regmap_read(data->regmap, INA238_DIAG_ALERT, ®val); + if (err) + return err; + + *val = !!(regval & INA238_DIAG_ALERT_TMPOL); + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int ina238_write_temp(struct device *dev, u32 attr, long val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int regval; + + if (attr != hwmon_temp_max) + return -EOPNOTSUPP; + + /* Signed, bits 15-4 of register */ + regval = (val / INA238_DIE_TEMP_LSB) << 4; + regval = clamp_val(regval, S16_MIN, S16_MAX) & 0xfff0; + + return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval); +} + +static int ina238_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + switch (type) { + case hwmon_in: + return ina238_read_in(dev, attr, channel, val); + case hwmon_curr: + return ina238_read_current(dev, attr, val); + case hwmon_power: + return ina238_read_power(dev, attr, val); + case hwmon_temp: + return ina238_read_temp(dev, attr, val); + default: + return -EOPNOTSUPP; + } + return 0; +} + +static int ina238_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + struct ina238_data *data = dev_get_drvdata(dev); + int err; + + mutex_lock(&data->config_lock); + + switch (type) { + case hwmon_in: + err = ina238_write_in(dev, attr, channel, val); + break; + case hwmon_power: + err = ina238_write_power(dev, attr, val); + break; + case hwmon_temp: + err = ina238_write_temp(dev, attr, val); + break; + default: + err = -EOPNOTSUPP; + break; + } + + mutex_unlock(&data->config_lock); + return err; +} + +static umode_t ina238_is_visible(const void *drvdata, + enum hwmon_sensor_types type, + u32 attr, int channel) +{ + switch (type) { + case hwmon_in: + switch (attr) { + case hwmon_in_input: + case hwmon_in_max_alarm: + case hwmon_in_min_alarm: + return 0444; + case hwmon_in_max: + case hwmon_in_min: + return 0644; + default: + return 0; + } + case hwmon_curr: + switch (attr) { + case hwmon_curr_input: + return 0444; + default: + return 0; + } + case hwmon_power: + switch (attr) { + case hwmon_power_input: + case hwmon_power_max_alarm: + return 0444; + case hwmon_power_max: + return 0644; + default: + return 0; + } + case hwmon_temp: + switch (attr) { + case hwmon_temp_input: + case hwmon_temp_max_alarm: + return 0444; + case hwmon_temp_max: + return 0644; + default: + return 0; + } + default: + return 0; + } +} + +#define INA238_HWMON_IN_CONFIG (HWMON_I_INPUT | \ + HWMON_I_MAX | HWMON_I_MAX_ALARM | \ + HWMON_I_MIN | HWMON_I_MIN_ALARM) + +static const struct hwmon_channel_info *ina238_info[] = { + HWMON_CHANNEL_INFO(in, + /* 0: shunt voltage */ + INA238_HWMON_IN_CONFIG, + /* 1: bus voltage */ + INA238_HWMON_IN_CONFIG), + HWMON_CHANNEL_INFO(curr, + /* 0: current through shunt */ + HWMON_C_INPUT), + HWMON_CHANNEL_INFO(power, + /* 0: power */ + HWMON_P_INPUT | HWMON_P_MAX | HWMON_P_MAX_ALARM), + HWMON_CHANNEL_INFO(temp, + /* 0: die temperature */ + HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM), + NULL +}; + +static const struct hwmon_ops ina238_hwmon_ops = { + .is_visible = ina238_is_visible, + .read = ina238_read, + .write = ina238_write, +}; + +static const struct hwmon_chip_info ina238_chip_info = { + .ops = &ina238_hwmon_ops, + .info = ina238_info, +}; + +static int ina238_probe(struct i2c_client *client) +{ + struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev); + struct device *dev = &client->dev; + struct device *hwmon_dev; + struct ina238_data *data; + int config; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + mutex_init(&data->config_lock); + + data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config); + if (IS_ERR(data->regmap)) { + dev_err(dev, "failed to allocate register map\n"); + return PTR_ERR(data->regmap); + } + + /* load shunt value */ + data->rshunt = INA238_RSHUNT_DEFAULT; + if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0 && pdata) + data->rshunt = pdata->shunt_uohms; + if (data->rshunt == 0) { + dev_err(dev, "invalid shunt resister value %u\n", data->rshunt); + return -EINVAL; + } + + /* load shunt gain value */ + if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0) + data->gain = 4; /* Default of ADCRANGE = 0 */ + if (data->gain != 1 && data->gain != 4) { + dev_err(dev, "invalid shunt gain value %u\n", data->gain); + return -EINVAL; + } + + /* Setup CONFIG register */ + config = INA238_CONFIG_DEFAULT; + if (data->gain == 1) + config |= INA238_CONFIG_ADCRANGE; /* ADCRANGE = 1 is /1 */ + ret = regmap_write(data->regmap, INA238_CONFIG, config); + if (ret < 0) { + dev_err(dev, "error configuring the device: %d\n", ret); + return -ENODEV; + } + + /* Setup ADC_CONFIG register */ + ret = regmap_write(data->regmap, INA238_ADC_CONFIG, + INA238_ADC_CONFIG_DEFAULT); + if (ret < 0) { + dev_err(dev, "error configuring the device: %d\n", ret); + return -ENODEV; + } + + /* Setup SHUNT_CALIBRATION register with fixed value */ + ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION, + INA238_CALIBRATION_VALUE); + if (ret < 0) { + dev_err(dev, "error configuring the device: %d\n", ret); + return -ENODEV; + } + + /* Setup alert/alarm configuration */ + ret = regmap_write(data->regmap, INA238_DIAG_ALERT, + INA238_DIAG_ALERT_DEFAULT); + if (ret < 0) { + dev_err(dev, "error configuring the device: %d\n", ret); + return -ENODEV; + } + + hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data, + &ina238_chip_info, + NULL); + if (IS_ERR(hwmon_dev)) + return PTR_ERR(hwmon_dev); + + dev_info(dev, "power monitor %s (Rshunt = %u uOhm, gain = %u)\n", + client->name, data->rshunt, data->gain); + + return 0; +} + +static const struct i2c_device_id ina238_id[] = { + { "ina238", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ina238_id); + +static const struct of_device_id __maybe_unused ina238_of_match[] = { + { .compatible = "ti,ina238" }, + { }, +}; +MODULE_DEVICE_TABLE(of, ina238_of_match); + +static struct i2c_driver ina238_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "ina238", + .of_match_table = of_match_ptr(ina238_of_match), + }, + .probe_new = ina238_probe, + .id_table = ina238_id, +}; + +module_i2c_driver(ina238_driver); + +MODULE_AUTHOR("Nathan Rossi <nathan.rossi@digi.com>"); +MODULE_DESCRIPTION("ina238 driver"); +MODULE_LICENSE("GPL"); |