1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for Linear Technology LTC4260 I2C Positive Voltage 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/i2c.h> 13 #include <linux/hwmon.h> 14 #include <linux/hwmon-sysfs.h> 15 #include <linux/jiffies.h> 16 #include <linux/regmap.h> 17 18 /* chip registers */ 19 #define LTC4260_CONTROL 0x00 20 #define LTC4260_ALERT 0x01 21 #define LTC4260_STATUS 0x02 22 #define LTC4260_FAULT 0x03 23 #define LTC4260_SENSE 0x04 24 #define LTC4260_SOURCE 0x05 25 #define LTC4260_ADIN 0x06 26 27 /* 28 * Fault register bits 29 */ 30 #define FAULT_OV (1 << 0) 31 #define FAULT_UV (1 << 1) 32 #define FAULT_OC (1 << 2) 33 #define FAULT_POWER_BAD (1 << 3) 34 #define FAULT_FET_SHORT (1 << 5) 35 36 /* Return the voltage from the given register in mV or mA */ 37 static int ltc4260_get_value(struct device *dev, u8 reg) 38 { 39 struct regmap *regmap = dev_get_drvdata(dev); 40 unsigned int val; 41 int ret; 42 43 ret = regmap_read(regmap, reg, &val); 44 if (ret < 0) 45 return ret; 46 47 switch (reg) { 48 case LTC4260_ADIN: 49 /* 10 mV resolution. Convert to mV. */ 50 val = val * 10; 51 break; 52 case LTC4260_SOURCE: 53 /* 400 mV resolution. Convert to mV. */ 54 val = val * 400; 55 break; 56 case LTC4260_SENSE: 57 /* 58 * 300 uV resolution. Convert to current as measured with 59 * an 1 mOhm sense resistor, in mA. If a different sense 60 * resistor is installed, calculate the actual current by 61 * dividing the reported current by the sense resistor value 62 * in mOhm. 63 */ 64 val = val * 300; 65 break; 66 default: 67 return -EINVAL; 68 } 69 70 return val; 71 } 72 73 static ssize_t ltc4260_value_show(struct device *dev, 74 struct device_attribute *da, char *buf) 75 { 76 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 77 int value; 78 79 value = ltc4260_get_value(dev, attr->index); 80 if (value < 0) 81 return value; 82 return sysfs_emit(buf, "%d\n", value); 83 } 84 85 static ssize_t ltc4260_bool_show(struct device *dev, 86 struct device_attribute *da, char *buf) 87 { 88 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 89 struct regmap *regmap = dev_get_drvdata(dev); 90 unsigned int fault; 91 int ret; 92 93 ret = regmap_read(regmap, LTC4260_FAULT, &fault); 94 if (ret < 0) 95 return ret; 96 97 fault &= attr->index; 98 if (fault) /* Clear reported faults in chip register */ 99 regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0); 100 101 return sysfs_emit(buf, "%d\n", !!fault); 102 } 103 104 /* Voltages */ 105 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE); 106 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN); 107 108 /* 109 * Voltage alarms 110 * UV/OV faults are associated with the input voltage, and the POWER BAD and 111 * FET SHORT faults are associated with the output voltage. 112 */ 113 static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV); 114 static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV); 115 static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool, 116 FAULT_POWER_BAD | FAULT_FET_SHORT); 117 118 /* Current (via sense resistor) */ 119 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE); 120 121 /* Overcurrent alarm */ 122 static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC); 123 124 static struct attribute *ltc4260_attrs[] = { 125 &sensor_dev_attr_in1_input.dev_attr.attr, 126 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 127 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 128 &sensor_dev_attr_in2_input.dev_attr.attr, 129 &sensor_dev_attr_in2_alarm.dev_attr.attr, 130 131 &sensor_dev_attr_curr1_input.dev_attr.attr, 132 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 133 134 NULL, 135 }; 136 ATTRIBUTE_GROUPS(ltc4260); 137 138 static const struct regmap_config ltc4260_regmap_config = { 139 .reg_bits = 8, 140 .val_bits = 8, 141 .max_register = LTC4260_ADIN, 142 }; 143 144 static int ltc4260_probe(struct i2c_client *client) 145 { 146 struct device *dev = &client->dev; 147 struct device *hwmon_dev; 148 struct regmap *regmap; 149 150 regmap = devm_regmap_init_i2c(client, <c4260_regmap_config); 151 if (IS_ERR(regmap)) { 152 dev_err(dev, "failed to allocate register map\n"); 153 return PTR_ERR(regmap); 154 } 155 156 /* Clear faults */ 157 regmap_write(regmap, LTC4260_FAULT, 0x00); 158 159 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 160 regmap, 161 ltc4260_groups); 162 return PTR_ERR_OR_ZERO(hwmon_dev); 163 } 164 165 static const struct i2c_device_id ltc4260_id[] = { 166 {"ltc4260", 0}, 167 { } 168 }; 169 170 MODULE_DEVICE_TABLE(i2c, ltc4260_id); 171 172 static struct i2c_driver ltc4260_driver = { 173 .driver = { 174 .name = "ltc4260", 175 }, 176 .probe_new = ltc4260_probe, 177 .id_table = ltc4260_id, 178 }; 179 180 module_i2c_driver(ltc4260_driver); 181 182 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 183 MODULE_DESCRIPTION("LTC4260 driver"); 184 MODULE_LICENSE("GPL"); 185