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 */ 56 static 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 97 static ssize_t ltc4222_value_show(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 } 108 109 static ssize_t ltc4222_bool_show(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 */ 128 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4222_value, LTC4222_SOURCE1); 129 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4222_value, LTC4222_ADIN1); 130 static SENSOR_DEVICE_ATTR_RO(in3_input, ltc4222_value, LTC4222_SOURCE2); 131 static SENSOR_DEVICE_ATTR_RO(in4_input, ltc4222_value, LTC4222_ADIN2); 132 133 /* 134 * Voltage alarms 135 * UV/OV faults are associated with the input voltage, and power bad and fet 136 * faults are associated with the output voltage. 137 */ 138 static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm, ltc4222_bool, LTC4222_FAULT1, 139 FAULT_UV); 140 static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm, ltc4222_bool, LTC4222_FAULT1, 141 FAULT_OV); 142 static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, ltc4222_bool, LTC4222_FAULT1, 143 FAULT_POWER_BAD | FAULT_FET_BAD); 144 145 static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm, ltc4222_bool, LTC4222_FAULT2, 146 FAULT_UV); 147 static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm, ltc4222_bool, LTC4222_FAULT2, 148 FAULT_OV); 149 static SENSOR_DEVICE_ATTR_2_RO(in4_alarm, ltc4222_bool, LTC4222_FAULT2, 150 FAULT_POWER_BAD | FAULT_FET_BAD); 151 152 /* Current (via sense resistor) */ 153 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4222_value, LTC4222_SENSE1); 154 static SENSOR_DEVICE_ATTR_RO(curr2_input, ltc4222_value, LTC4222_SENSE2); 155 156 /* Overcurrent alarm */ 157 static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm, ltc4222_bool, LTC4222_FAULT1, 158 FAULT_OC); 159 static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm, ltc4222_bool, LTC4222_FAULT2, 160 FAULT_OC); 161 162 static struct attribute *ltc4222_attrs[] = { 163 &sensor_dev_attr_in1_input.dev_attr.attr, 164 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 165 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 166 &sensor_dev_attr_in2_input.dev_attr.attr, 167 &sensor_dev_attr_in2_alarm.dev_attr.attr, 168 &sensor_dev_attr_in3_input.dev_attr.attr, 169 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 170 &sensor_dev_attr_in3_max_alarm.dev_attr.attr, 171 &sensor_dev_attr_in4_input.dev_attr.attr, 172 &sensor_dev_attr_in4_alarm.dev_attr.attr, 173 174 &sensor_dev_attr_curr1_input.dev_attr.attr, 175 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 176 &sensor_dev_attr_curr2_input.dev_attr.attr, 177 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 178 179 NULL, 180 }; 181 ATTRIBUTE_GROUPS(ltc4222); 182 183 static const struct regmap_config ltc4222_regmap_config = { 184 .reg_bits = 8, 185 .val_bits = 8, 186 .max_register = LTC4222_ADC_CONTROL, 187 }; 188 189 static int ltc4222_probe(struct i2c_client *client, 190 const struct i2c_device_id *id) 191 { 192 struct device *dev = &client->dev; 193 struct device *hwmon_dev; 194 struct regmap *regmap; 195 196 regmap = devm_regmap_init_i2c(client, <c4222_regmap_config); 197 if (IS_ERR(regmap)) { 198 dev_err(dev, "failed to allocate register map\n"); 199 return PTR_ERR(regmap); 200 } 201 202 /* Clear faults */ 203 regmap_write(regmap, LTC4222_FAULT1, 0x00); 204 regmap_write(regmap, LTC4222_FAULT2, 0x00); 205 206 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 207 regmap, 208 ltc4222_groups); 209 return PTR_ERR_OR_ZERO(hwmon_dev); 210 } 211 212 static const struct i2c_device_id ltc4222_id[] = { 213 {"ltc4222", 0}, 214 { } 215 }; 216 217 MODULE_DEVICE_TABLE(i2c, ltc4222_id); 218 219 static struct i2c_driver ltc4222_driver = { 220 .driver = { 221 .name = "ltc4222", 222 }, 223 .probe = ltc4222_probe, 224 .id_table = ltc4222_id, 225 }; 226 227 module_i2c_driver(ltc4222_driver); 228 229 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 230 MODULE_DESCRIPTION("LTC4222 driver"); 231 MODULE_LICENSE("GPL"); 232