1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for Linear Technology LTC4222 Dual Hot Swap controller 4 * 5 * Copyright (c) 2014 Guenter Roeck 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/err.h> 11 #include <linux/slab.h> 12 #include <linux/bitops.h> 13 #include <linux/i2c.h> 14 #include <linux/hwmon.h> 15 #include <linux/hwmon-sysfs.h> 16 #include <linux/jiffies.h> 17 #include <linux/regmap.h> 18 19 /* chip registers */ 20 21 #define LTC4222_CONTROL1 0xd0 22 #define LTC4222_ALERT1 0xd1 23 #define LTC4222_STATUS1 0xd2 24 #define LTC4222_FAULT1 0xd3 25 #define LTC4222_CONTROL2 0xd4 26 #define LTC4222_ALERT2 0xd5 27 #define LTC4222_STATUS2 0xd6 28 #define LTC4222_FAULT2 0xd7 29 #define LTC4222_SOURCE1 0xd8 30 #define LTC4222_SOURCE2 0xda 31 #define LTC4222_ADIN1 0xdc 32 #define LTC4222_ADIN2 0xde 33 #define LTC4222_SENSE1 0xe0 34 #define LTC4222_SENSE2 0xe2 35 #define LTC4222_ADC_CONTROL 0xe4 36 37 /* 38 * Fault register bits 39 */ 40 #define FAULT_OV BIT(0) 41 #define FAULT_UV BIT(1) 42 #define FAULT_OC BIT(2) 43 #define FAULT_POWER_BAD BIT(3) 44 #define FAULT_FET_BAD BIT(5) 45 46 /* Return the voltage from the given register in mV or mA */ 47 static int ltc4222_get_value(struct device *dev, u8 reg) 48 { 49 struct regmap *regmap = dev_get_drvdata(dev); 50 unsigned int val; 51 u8 buf[2]; 52 int ret; 53 54 ret = regmap_bulk_read(regmap, reg, buf, 2); 55 if (ret < 0) 56 return ret; 57 58 val = ((buf[0] << 8) + buf[1]) >> 6; 59 60 switch (reg) { 61 case LTC4222_ADIN1: 62 case LTC4222_ADIN2: 63 /* 1.25 mV resolution. Convert to mV. */ 64 val = DIV_ROUND_CLOSEST(val * 5, 4); 65 break; 66 case LTC4222_SOURCE1: 67 case LTC4222_SOURCE2: 68 /* 31.25 mV resolution. Convert to mV. */ 69 val = DIV_ROUND_CLOSEST(val * 125, 4); 70 break; 71 case LTC4222_SENSE1: 72 case LTC4222_SENSE2: 73 /* 74 * 62.5 uV resolution. Convert to current as measured with 75 * an 1 mOhm sense resistor, in mA. If a different sense 76 * resistor is installed, calculate the actual current by 77 * dividing the reported current by the sense resistor value 78 * in mOhm. 79 */ 80 val = DIV_ROUND_CLOSEST(val * 125, 2); 81 break; 82 default: 83 return -EINVAL; 84 } 85 return val; 86 } 87 88 static ssize_t ltc4222_value_show(struct device *dev, 89 struct device_attribute *da, char *buf) 90 { 91 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 92 int value; 93 94 value = ltc4222_get_value(dev, attr->index); 95 if (value < 0) 96 return value; 97 return snprintf(buf, PAGE_SIZE, "%d\n", value); 98 } 99 100 static ssize_t ltc4222_bool_show(struct device *dev, 101 struct device_attribute *da, char *buf) 102 { 103 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); 104 struct regmap *regmap = dev_get_drvdata(dev); 105 unsigned int fault; 106 int ret; 107 108 ret = regmap_read(regmap, attr->nr, &fault); 109 if (ret < 0) 110 return ret; 111 fault &= attr->index; 112 if (fault) /* Clear reported faults in chip register */ 113 regmap_update_bits(regmap, attr->nr, attr->index, 0); 114 115 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); 116 } 117 118 /* Voltages */ 119 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4222_value, LTC4222_SOURCE1); 120 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4222_value, LTC4222_ADIN1); 121 static SENSOR_DEVICE_ATTR_RO(in3_input, ltc4222_value, LTC4222_SOURCE2); 122 static SENSOR_DEVICE_ATTR_RO(in4_input, ltc4222_value, LTC4222_ADIN2); 123 124 /* 125 * Voltage alarms 126 * UV/OV faults are associated with the input voltage, and power bad and fet 127 * faults are associated with the output voltage. 128 */ 129 static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm, ltc4222_bool, LTC4222_FAULT1, 130 FAULT_UV); 131 static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm, ltc4222_bool, LTC4222_FAULT1, 132 FAULT_OV); 133 static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, ltc4222_bool, LTC4222_FAULT1, 134 FAULT_POWER_BAD | FAULT_FET_BAD); 135 136 static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm, ltc4222_bool, LTC4222_FAULT2, 137 FAULT_UV); 138 static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm, ltc4222_bool, LTC4222_FAULT2, 139 FAULT_OV); 140 static SENSOR_DEVICE_ATTR_2_RO(in4_alarm, ltc4222_bool, LTC4222_FAULT2, 141 FAULT_POWER_BAD | FAULT_FET_BAD); 142 143 /* Current (via sense resistor) */ 144 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4222_value, LTC4222_SENSE1); 145 static SENSOR_DEVICE_ATTR_RO(curr2_input, ltc4222_value, LTC4222_SENSE2); 146 147 /* Overcurrent alarm */ 148 static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm, ltc4222_bool, LTC4222_FAULT1, 149 FAULT_OC); 150 static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm, ltc4222_bool, LTC4222_FAULT2, 151 FAULT_OC); 152 153 static struct attribute *ltc4222_attrs[] = { 154 &sensor_dev_attr_in1_input.dev_attr.attr, 155 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 156 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 157 &sensor_dev_attr_in2_input.dev_attr.attr, 158 &sensor_dev_attr_in2_alarm.dev_attr.attr, 159 &sensor_dev_attr_in3_input.dev_attr.attr, 160 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 161 &sensor_dev_attr_in3_max_alarm.dev_attr.attr, 162 &sensor_dev_attr_in4_input.dev_attr.attr, 163 &sensor_dev_attr_in4_alarm.dev_attr.attr, 164 165 &sensor_dev_attr_curr1_input.dev_attr.attr, 166 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 167 &sensor_dev_attr_curr2_input.dev_attr.attr, 168 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 169 170 NULL, 171 }; 172 ATTRIBUTE_GROUPS(ltc4222); 173 174 static const struct regmap_config ltc4222_regmap_config = { 175 .reg_bits = 8, 176 .val_bits = 8, 177 .max_register = LTC4222_ADC_CONTROL, 178 }; 179 180 static int ltc4222_probe(struct i2c_client *client) 181 { 182 struct device *dev = &client->dev; 183 struct device *hwmon_dev; 184 struct regmap *regmap; 185 186 regmap = devm_regmap_init_i2c(client, <c4222_regmap_config); 187 if (IS_ERR(regmap)) { 188 dev_err(dev, "failed to allocate register map\n"); 189 return PTR_ERR(regmap); 190 } 191 192 /* Clear faults */ 193 regmap_write(regmap, LTC4222_FAULT1, 0x00); 194 regmap_write(regmap, LTC4222_FAULT2, 0x00); 195 196 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 197 regmap, 198 ltc4222_groups); 199 return PTR_ERR_OR_ZERO(hwmon_dev); 200 } 201 202 static const struct i2c_device_id ltc4222_id[] = { 203 {"ltc4222", 0}, 204 { } 205 }; 206 207 MODULE_DEVICE_TABLE(i2c, ltc4222_id); 208 209 static struct i2c_driver ltc4222_driver = { 210 .driver = { 211 .name = "ltc4222", 212 }, 213 .probe_new = ltc4222_probe, 214 .id_table = ltc4222_id, 215 }; 216 217 module_i2c_driver(ltc4222_driver); 218 219 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 220 MODULE_DESCRIPTION("LTC4222 driver"); 221 MODULE_LICENSE("GPL"); 222