/* * Driver for Linear Technology LTC4222 Dual Hot Swap controller * * Copyright (c) 2014 Guenter Roeck * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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 #include #include #include #include #include #include #include #include #include /* chip registers */ #define LTC4222_CONTROL1 0xd0 #define LTC4222_ALERT1 0xd1 #define LTC4222_STATUS1 0xd2 #define LTC4222_FAULT1 0xd3 #define LTC4222_CONTROL2 0xd4 #define LTC4222_ALERT2 0xd5 #define LTC4222_STATUS2 0xd6 #define LTC4222_FAULT2 0xd7 #define LTC4222_SOURCE1 0xd8 #define LTC4222_SOURCE2 0xda #define LTC4222_ADIN1 0xdc #define LTC4222_ADIN2 0xde #define LTC4222_SENSE1 0xe0 #define LTC4222_SENSE2 0xe2 #define LTC4222_ADC_CONTROL 0xe4 /* * Fault register bits */ #define FAULT_OV BIT(0) #define FAULT_UV BIT(1) #define FAULT_OC BIT(2) #define FAULT_POWER_BAD BIT(3) #define FAULT_FET_BAD BIT(5) /* Return the voltage from the given register in mV or mA */ static int ltc4222_get_value(struct device *dev, u8 reg) { struct regmap *regmap = dev_get_drvdata(dev); unsigned int val; u8 buf[2]; int ret; ret = regmap_bulk_read(regmap, reg, buf, 2); if (ret < 0) return ret; val = ((buf[0] << 8) + buf[1]) >> 6; switch (reg) { case LTC4222_ADIN1: case LTC4222_ADIN2: /* 1.25 mV resolution. Convert to mV. */ val = DIV_ROUND_CLOSEST(val * 5, 4); break; case LTC4222_SOURCE1: case LTC4222_SOURCE2: /* 31.25 mV resolution. Convert to mV. */ val = DIV_ROUND_CLOSEST(val * 125, 4); break; case LTC4222_SENSE1: case LTC4222_SENSE2: /* * 62.5 uV resolution. Convert to current as measured with * an 1 mOhm sense resistor, in mA. If a different sense * resistor is installed, calculate the actual current by * dividing the reported current by the sense resistor value * in mOhm. */ val = DIV_ROUND_CLOSEST(val * 125, 2); break; default: return -EINVAL; } return val; } static ssize_t ltc4222_show_value(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); int value; value = ltc4222_get_value(dev, attr->index); if (value < 0) return value; return snprintf(buf, PAGE_SIZE, "%d\n", value); } static ssize_t ltc4222_show_bool(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); struct regmap *regmap = dev_get_drvdata(dev); unsigned int fault; int ret; ret = regmap_read(regmap, attr->nr, &fault); if (ret < 0) return ret; fault &= attr->index; if (fault) /* Clear reported faults in chip register */ regmap_update_bits(regmap, attr->nr, attr->index, 0); return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); } /* Voltages */ static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_SOURCE1); static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_ADIN1); static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_SOURCE2); static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_ADIN2); /* * Voltage alarms * UV/OV faults are associated with the input voltage, and power bad and fet * faults are associated with the output voltage. */ static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT1, FAULT_UV); static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT1, FAULT_OV); static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD); static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT2, FAULT_UV); static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT2, FAULT_OV); static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD); /* Current (via sense resistor) */ static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_SENSE1); static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL, LTC4222_SENSE2); /* Overcurrent alarm */ static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT1, FAULT_OC); static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, LTC4222_FAULT2, FAULT_OC); static struct attribute *ltc4222_attrs[] = { &sensor_dev_attr_in1_input.dev_attr.attr, &sensor_dev_attr_in1_min_alarm.dev_attr.attr, &sensor_dev_attr_in1_max_alarm.dev_attr.attr, &sensor_dev_attr_in2_input.dev_attr.attr, &sensor_dev_attr_in2_alarm.dev_attr.attr, &sensor_dev_attr_in3_input.dev_attr.attr, &sensor_dev_attr_in3_min_alarm.dev_attr.attr, &sensor_dev_attr_in3_max_alarm.dev_attr.attr, &sensor_dev_attr_in4_input.dev_attr.attr, &sensor_dev_attr_in4_alarm.dev_attr.attr, &sensor_dev_attr_curr1_input.dev_attr.attr, &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, &sensor_dev_attr_curr2_input.dev_attr.attr, &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, NULL, }; ATTRIBUTE_GROUPS(ltc4222); static const struct regmap_config ltc4222_regmap_config = { .reg_bits = 8, .val_bits = 8, .max_register = LTC4222_ADC_CONTROL, }; static int ltc4222_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct device *hwmon_dev; struct regmap *regmap; regmap = devm_regmap_init_i2c(client, <c4222_regmap_config); if (IS_ERR(regmap)) { dev_err(dev, "failed to allocate register map\n"); return PTR_ERR(regmap); } /* Clear faults */ regmap_write(regmap, LTC4222_FAULT1, 0x00); regmap_write(regmap, LTC4222_FAULT2, 0x00); hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, regmap, ltc4222_groups); return PTR_ERR_OR_ZERO(hwmon_dev); } static const struct i2c_device_id ltc4222_id[] = { {"ltc4222", 0}, { } }; MODULE_DEVICE_TABLE(i2c, ltc4222_id); static struct i2c_driver ltc4222_driver = { .driver = { .name = "ltc4222", }, .probe = ltc4222_probe, .id_table = ltc4222_id, }; module_i2c_driver(ltc4222_driver); MODULE_AUTHOR("Guenter Roeck "); MODULE_DESCRIPTION("LTC4222 driver"); MODULE_LICENSE("GPL");