1/* 2 * Driver for Linear Technology LTC4222 Dual Hot Swap controller 3 * 4 * Copyright (c) 2014 Guenter Roeck 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17#include <linux/kernel.h> 18#include <linux/module.h> 19#include <linux/err.h> 20#include <linux/slab.h> 21#include <linux/bitops.h> 22#include <linux/i2c.h> 23#include <linux/hwmon.h> 24#include <linux/hwmon-sysfs.h> 25#include <linux/jiffies.h> 26#include <linux/regmap.h> 27 28/* chip registers */ 29 30#define LTC4222_CONTROL1 0xd0 31#define LTC4222_ALERT1 0xd1 32#define LTC4222_STATUS1 0xd2 33#define LTC4222_FAULT1 0xd3 34#define LTC4222_CONTROL2 0xd4 35#define LTC4222_ALERT2 0xd5 36#define LTC4222_STATUS2 0xd6 37#define LTC4222_FAULT2 0xd7 38#define LTC4222_SOURCE1 0xd8 39#define LTC4222_SOURCE2 0xda 40#define LTC4222_ADIN1 0xdc 41#define LTC4222_ADIN2 0xde 42#define LTC4222_SENSE1 0xe0 43#define LTC4222_SENSE2 0xe2 44#define LTC4222_ADC_CONTROL 0xe4 45 46/* 47 * Fault register bits 48 */ 49#define FAULT_OV BIT(0) 50#define FAULT_UV BIT(1) 51#define FAULT_OC BIT(2) 52#define FAULT_POWER_BAD BIT(3) 53#define FAULT_FET_BAD BIT(5) 54 55/* Return the voltage from the given register in mV or mA */ 56static int ltc4222_get_value(struct device *dev, u8 reg) 57{ 58 struct regmap *regmap = dev_get_drvdata(dev); 59 unsigned int val; 60 u8 buf[2]; 61 int ret; 62 63 ret = regmap_bulk_read(regmap, reg, buf, 2); 64 if (ret < 0) 65 return ret; 66 67 val = ((buf[0] << 8) + buf[1]) >> 6; 68 69 switch (reg) { 70 case LTC4222_ADIN1: 71 case LTC4222_ADIN2: 72 /* 1.25 mV resolution. Convert to mV. */ 73 val = DIV_ROUND_CLOSEST(val * 5, 4); 74 break; 75 case LTC4222_SOURCE1: 76 case LTC4222_SOURCE2: 77 /* 31.25 mV resolution. Convert to mV. */ 78 val = DIV_ROUND_CLOSEST(val * 125, 4); 79 break; 80 case LTC4222_SENSE1: 81 case LTC4222_SENSE2: 82 /* 83 * 62.5 uV resolution. Convert to current as measured with 84 * an 1 mOhm sense resistor, in mA. If a different sense 85 * resistor is installed, calculate the actual current by 86 * dividing the reported current by the sense resistor value 87 * in mOhm. 88 */ 89 val = DIV_ROUND_CLOSEST(val * 125, 2); 90 break; 91 default: 92 return -EINVAL; 93 } 94 return val; 95} 96 97static ssize_t ltc4222_show_value(struct device *dev, 98 struct device_attribute *da, char *buf) 99{ 100 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 101 int value; 102 103 value = ltc4222_get_value(dev, attr->index); 104 if (value < 0) 105 return value; 106 return snprintf(buf, PAGE_SIZE, "%d\n", value); 107} 108 109static ssize_t ltc4222_show_bool(struct device *dev, 110 struct device_attribute *da, char *buf) 111{ 112 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); 113 struct regmap *regmap = dev_get_drvdata(dev); 114 unsigned int fault; 115 int ret; 116 117 ret = regmap_read(regmap, attr->nr, &fault); 118 if (ret < 0) 119 return ret; 120 fault &= attr->index; 121 if (fault) /* Clear reported faults in chip register */ 122 regmap_update_bits(regmap, attr->nr, attr->index, 0); 123 124 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); 125} 126 127/* Voltages */ 128static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL, 129 LTC4222_SOURCE1); 130static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL, 131 LTC4222_ADIN1); 132static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL, 133 LTC4222_SOURCE2); 134static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL, 135 LTC4222_ADIN2); 136 137/* 138 * Voltage alarms 139 * UV/OV faults are associated with the input voltage, and power bad and fet 140 * faults are associated with the output voltage. 141 */ 142static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL, 143 LTC4222_FAULT1, FAULT_UV); 144static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, 145 LTC4222_FAULT1, FAULT_OV); 146static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL, 147 LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD); 148 149static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL, 150 LTC4222_FAULT2, FAULT_UV); 151static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, 152 LTC4222_FAULT2, FAULT_OV); 153static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL, 154 LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD); 155 156/* Current (via sense resistor) */ 157static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL, 158 LTC4222_SENSE1); 159static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL, 160 LTC4222_SENSE2); 161 162/* Overcurrent alarm */ 163static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, 164 LTC4222_FAULT1, FAULT_OC); 165static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL, 166 LTC4222_FAULT2, FAULT_OC); 167 168static struct attribute *ltc4222_attrs[] = { 169 &sensor_dev_attr_in1_input.dev_attr.attr, 170 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 171 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 172 &sensor_dev_attr_in2_input.dev_attr.attr, 173 &sensor_dev_attr_in2_alarm.dev_attr.attr, 174 &sensor_dev_attr_in3_input.dev_attr.attr, 175 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 176 &sensor_dev_attr_in3_max_alarm.dev_attr.attr, 177 &sensor_dev_attr_in4_input.dev_attr.attr, 178 &sensor_dev_attr_in4_alarm.dev_attr.attr, 179 180 &sensor_dev_attr_curr1_input.dev_attr.attr, 181 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 182 &sensor_dev_attr_curr2_input.dev_attr.attr, 183 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 184 185 NULL, 186}; 187ATTRIBUTE_GROUPS(ltc4222); 188 189static const struct regmap_config ltc4222_regmap_config = { 190 .reg_bits = 8, 191 .val_bits = 8, 192 .max_register = LTC4222_ADC_CONTROL, 193}; 194 195static int ltc4222_probe(struct i2c_client *client, 196 const struct i2c_device_id *id) 197{ 198 struct device *dev = &client->dev; 199 struct device *hwmon_dev; 200 struct regmap *regmap; 201 202 regmap = devm_regmap_init_i2c(client, <c4222_regmap_config); 203 if (IS_ERR(regmap)) { 204 dev_err(dev, "failed to allocate register map\n"); 205 return PTR_ERR(regmap); 206 } 207 208 /* Clear faults */ 209 regmap_write(regmap, LTC4222_FAULT1, 0x00); 210 regmap_write(regmap, LTC4222_FAULT2, 0x00); 211 212 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 213 regmap, 214 ltc4222_groups); 215 return PTR_ERR_OR_ZERO(hwmon_dev); 216} 217 218static const struct i2c_device_id ltc4222_id[] = { 219 {"ltc4222", 0}, 220 { } 221}; 222 223MODULE_DEVICE_TABLE(i2c, ltc4222_id); 224 225static struct i2c_driver ltc4222_driver = { 226 .driver = { 227 .name = "ltc4222", 228 }, 229 .probe = ltc4222_probe, 230 .id_table = ltc4222_id, 231}; 232 233module_i2c_driver(ltc4222_driver); 234 235MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 236MODULE_DESCRIPTION("LTC4222 driver"); 237MODULE_LICENSE("GPL"); 238