/* * Driver for Linear Technology LTC2990 power monitor * * Copyright (C) 2014 Topic Embedded Products * Author: Mike Looijmans <mike.looijmans@topic.nl> * * License: GPLv2 * * This driver assumes the chip is wired as a dual current monitor, and * reports the voltage drop across two series resistors. It also reports * the chip's internal temperature and Vcc power supply voltage. */ #include <linux/err.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/i2c.h> #include <linux/kernel.h> #include <linux/module.h> #define LTC2990_STATUS 0x00 #define LTC2990_CONTROL 0x01 #define LTC2990_TRIGGER 0x02 #define LTC2990_TINT_MSB 0x04 #define LTC2990_V1_MSB 0x06 #define LTC2990_V2_MSB 0x08 #define LTC2990_V3_MSB 0x0A #define LTC2990_V4_MSB 0x0C #define LTC2990_VCC_MSB 0x0E #define LTC2990_CONTROL_KELVIN BIT(7) #define LTC2990_CONTROL_SINGLE BIT(6) #define LTC2990_CONTROL_MEASURE_ALL (0x3 << 3) #define LTC2990_CONTROL_MODE_CURRENT 0x06 #define LTC2990_CONTROL_MODE_VOLTAGE 0x07 /* convert raw register value to sign-extended integer in 16-bit range */ static int ltc2990_voltage_to_int(int raw) { if (raw & BIT(14)) return -(0x4000 - (raw & 0x3FFF)) << 2; else return (raw & 0x3FFF) << 2; } /* Return the converted value from the given register in uV or mC */ static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) { int val; val = i2c_smbus_read_word_swapped(i2c, reg); if (unlikely(val < 0)) return val; switch (reg) { case LTC2990_TINT_MSB: /* internal temp, 0.0625 degrees/LSB, 13-bit */ val = (val & 0x1FFF) << 3; *result = (val * 1000) >> 7; break; case LTC2990_V1_MSB: case LTC2990_V3_MSB: /* Vx-Vy, 19.42uV/LSB. Depends on mode. */ *result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100); break; case LTC2990_VCC_MSB: /* Vcc, 305.18μV/LSB, 2.5V offset */ *result = (ltc2990_voltage_to_int(val) * 30518 / (4 * 100 * 1000)) + 2500; break; default: return -EINVAL; /* won't happen, keep compiler happy */ } return 0; } static ssize_t ltc2990_show_value(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); int value; int ret; ret = ltc2990_get_value(dev_get_drvdata(dev), attr->index, &value); if (unlikely(ret < 0)) return ret; return snprintf(buf, PAGE_SIZE, "%d\n", value); } static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ltc2990_show_value, NULL, LTC2990_TINT_MSB); static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2990_show_value, NULL, LTC2990_V1_MSB); static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc2990_show_value, NULL, LTC2990_V3_MSB); static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value, NULL, LTC2990_VCC_MSB); static struct attribute *ltc2990_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_curr1_input.dev_attr.attr, &sensor_dev_attr_curr2_input.dev_attr.attr, &sensor_dev_attr_in0_input.dev_attr.attr, NULL, }; ATTRIBUTE_GROUPS(ltc2990); static int ltc2990_i2c_probe(struct i2c_client *i2c, const struct i2c_device_id *id) { int ret; struct device *hwmon_dev; if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) return -ENODEV; /* Setup continuous mode, current monitor */ ret = i2c_smbus_write_byte_data(i2c, LTC2990_CONTROL, LTC2990_CONTROL_MEASURE_ALL | LTC2990_CONTROL_MODE_CURRENT); if (ret < 0) { dev_err(&i2c->dev, "Error: Failed to set control mode.\n"); return ret; } /* Trigger once to start continuous conversion */ ret = i2c_smbus_write_byte_data(i2c, LTC2990_TRIGGER, 1); if (ret < 0) { dev_err(&i2c->dev, "Error: Failed to start acquisition.\n"); return ret; } hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev, i2c->name, i2c, ltc2990_groups); return PTR_ERR_OR_ZERO(hwmon_dev); } static const struct i2c_device_id ltc2990_i2c_id[] = { { "ltc2990", 0 }, {} }; MODULE_DEVICE_TABLE(i2c, ltc2990_i2c_id); static struct i2c_driver ltc2990_i2c_driver = { .driver = { .name = "ltc2990", }, .probe = ltc2990_i2c_probe, .id_table = ltc2990_i2c_id, }; module_i2c_driver(ltc2990_i2c_driver); MODULE_DESCRIPTION("LTC2990 Sensor Driver"); MODULE_AUTHOR("Topic Embedded Products"); MODULE_LICENSE("GPL v2");