Guenter Roeck | 69e1ded | 2014-01-11 00:17:05 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Driver for Linear Technology LTC4260 I2C Positive Voltage 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/i2c.h> |
| 22 | #include <linux/hwmon.h> |
| 23 | #include <linux/hwmon-sysfs.h> |
| 24 | #include <linux/jiffies.h> |
| 25 | #include <linux/regmap.h> |
| 26 | |
| 27 | /* chip registers */ |
| 28 | #define LTC4260_CONTROL 0x00 |
| 29 | #define LTC4260_ALERT 0x01 |
| 30 | #define LTC4260_STATUS 0x02 |
| 31 | #define LTC4260_FAULT 0x03 |
| 32 | #define LTC4260_SENSE 0x04 |
| 33 | #define LTC4260_SOURCE 0x05 |
| 34 | #define LTC4260_ADIN 0x06 |
| 35 | |
| 36 | /* |
| 37 | * Fault register bits |
| 38 | */ |
| 39 | #define FAULT_OV (1 << 0) |
| 40 | #define FAULT_UV (1 << 1) |
| 41 | #define FAULT_OC (1 << 2) |
| 42 | #define FAULT_POWER_BAD (1 << 3) |
| 43 | #define FAULT_FET_SHORT (1 << 5) |
| 44 | |
| 45 | /* Return the voltage from the given register in mV or mA */ |
| 46 | static int ltc4260_get_value(struct device *dev, u8 reg) |
| 47 | { |
| 48 | struct regmap *regmap = dev_get_drvdata(dev); |
| 49 | unsigned int val; |
| 50 | int ret; |
| 51 | |
| 52 | ret = regmap_read(regmap, reg, &val); |
| 53 | if (ret < 0) |
| 54 | return ret; |
| 55 | |
| 56 | switch (reg) { |
| 57 | case LTC4260_ADIN: |
| 58 | /* 10 mV resolution. Convert to mV. */ |
| 59 | val = val * 10; |
| 60 | break; |
| 61 | case LTC4260_SOURCE: |
| 62 | /* 400 mV resolution. Convert to mV. */ |
| 63 | val = val * 400; |
| 64 | break; |
| 65 | case LTC4260_SENSE: |
| 66 | /* |
| 67 | * 300 uV resolution. Convert to current as measured with |
| 68 | * an 1 mOhm sense resistor, in mA. If a different sense |
| 69 | * resistor is installed, calculate the actual current by |
| 70 | * dividing the reported current by the sense resistor value |
| 71 | * in mOhm. |
| 72 | */ |
| 73 | val = val * 300; |
| 74 | break; |
| 75 | default: |
| 76 | return -EINVAL; |
| 77 | } |
| 78 | |
| 79 | return val; |
| 80 | } |
| 81 | |
| 82 | static ssize_t ltc4260_show_value(struct device *dev, |
| 83 | struct device_attribute *da, char *buf) |
| 84 | { |
| 85 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
| 86 | int value; |
| 87 | |
| 88 | value = ltc4260_get_value(dev, attr->index); |
| 89 | if (value < 0) |
| 90 | return value; |
| 91 | return snprintf(buf, PAGE_SIZE, "%d\n", value); |
| 92 | } |
| 93 | |
| 94 | static ssize_t ltc4260_show_bool(struct device *dev, |
| 95 | struct device_attribute *da, char *buf) |
| 96 | { |
| 97 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
| 98 | struct regmap *regmap = dev_get_drvdata(dev); |
| 99 | unsigned int fault; |
| 100 | int ret; |
| 101 | |
| 102 | ret = regmap_read(regmap, LTC4260_FAULT, &fault); |
| 103 | if (ret < 0) |
| 104 | return ret; |
| 105 | |
| 106 | fault &= attr->index; |
| 107 | if (fault) /* Clear reported faults in chip register */ |
| 108 | regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0); |
| 109 | |
| 110 | return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); |
| 111 | } |
| 112 | |
| 113 | /* Voltages */ |
| 114 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4260_show_value, NULL, |
| 115 | LTC4260_SOURCE); |
| 116 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4260_show_value, NULL, |
| 117 | LTC4260_ADIN); |
| 118 | |
| 119 | /* |
| 120 | * Voltage alarms |
| 121 | * UV/OV faults are associated with the input voltage, and the POWER BAD and |
| 122 | * FET SHORT faults are associated with the output voltage. |
| 123 | */ |
| 124 | static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4260_show_bool, NULL, |
| 125 | FAULT_UV); |
| 126 | static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL, |
| 127 | FAULT_OV); |
| 128 | static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, ltc4260_show_bool, NULL, |
| 129 | FAULT_POWER_BAD | FAULT_FET_SHORT); |
| 130 | |
| 131 | /* Current (via sense resistor) */ |
| 132 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4260_show_value, NULL, |
| 133 | LTC4260_SENSE); |
| 134 | |
| 135 | /* Overcurrent alarm */ |
| 136 | static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL, |
| 137 | FAULT_OC); |
| 138 | |
| 139 | static struct attribute *ltc4260_attrs[] = { |
| 140 | &sensor_dev_attr_in1_input.dev_attr.attr, |
| 141 | &sensor_dev_attr_in1_min_alarm.dev_attr.attr, |
| 142 | &sensor_dev_attr_in1_max_alarm.dev_attr.attr, |
| 143 | &sensor_dev_attr_in2_input.dev_attr.attr, |
| 144 | &sensor_dev_attr_in2_alarm.dev_attr.attr, |
| 145 | |
| 146 | &sensor_dev_attr_curr1_input.dev_attr.attr, |
| 147 | &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, |
| 148 | |
| 149 | NULL, |
| 150 | }; |
| 151 | ATTRIBUTE_GROUPS(ltc4260); |
| 152 | |
Axel Lin | 034b44b | 2014-07-02 08:42:18 +0800 | [diff] [blame] | 153 | static const struct regmap_config ltc4260_regmap_config = { |
Guenter Roeck | 69e1ded | 2014-01-11 00:17:05 -0800 | [diff] [blame] | 154 | .reg_bits = 8, |
| 155 | .val_bits = 8, |
| 156 | .max_register = LTC4260_ADIN, |
| 157 | }; |
| 158 | |
| 159 | static int ltc4260_probe(struct i2c_client *client, |
| 160 | const struct i2c_device_id *id) |
| 161 | { |
| 162 | struct device *dev = &client->dev; |
| 163 | struct device *hwmon_dev; |
| 164 | struct regmap *regmap; |
| 165 | |
| 166 | regmap = devm_regmap_init_i2c(client, <c4260_regmap_config); |
| 167 | if (IS_ERR(regmap)) { |
| 168 | dev_err(dev, "failed to allocate register map\n"); |
| 169 | return PTR_ERR(regmap); |
| 170 | } |
| 171 | |
| 172 | /* Clear faults */ |
| 173 | regmap_write(regmap, LTC4260_FAULT, 0x00); |
| 174 | |
| 175 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
| 176 | regmap, |
| 177 | ltc4260_groups); |
| 178 | return PTR_ERR_OR_ZERO(hwmon_dev); |
| 179 | } |
| 180 | |
| 181 | static const struct i2c_device_id ltc4260_id[] = { |
| 182 | {"ltc4260", 0}, |
| 183 | { } |
| 184 | }; |
| 185 | |
| 186 | MODULE_DEVICE_TABLE(i2c, ltc4260_id); |
| 187 | |
| 188 | static struct i2c_driver ltc4260_driver = { |
| 189 | .driver = { |
| 190 | .name = "ltc4260", |
| 191 | }, |
| 192 | .probe = ltc4260_probe, |
| 193 | .id_table = ltc4260_id, |
| 194 | }; |
| 195 | |
| 196 | module_i2c_driver(ltc4260_driver); |
| 197 | |
| 198 | MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); |
| 199 | MODULE_DESCRIPTION("LTC4260 driver"); |
| 200 | MODULE_LICENSE("GPL"); |