2 * Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller
4 * Copyright (c) 2014 Guenter Roeck
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.
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.
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>
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
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)
45 /* Return the voltage from the given register in mV or mA */
46 static int ltc4260_get_value(struct device *dev, u8 reg)
48 struct regmap *regmap = dev_get_drvdata(dev);
52 ret = regmap_read(regmap, reg, &val);
58 /* 10 mV resolution. Convert to mV. */
62 /* 400 mV resolution. Convert to mV. */
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
82 static ssize_t ltc4260_value_show(struct device *dev,
83 struct device_attribute *da, char *buf)
85 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
88 value = ltc4260_get_value(dev, attr->index);
91 return snprintf(buf, PAGE_SIZE, "%d\n", value);
94 static ssize_t ltc4260_bool_show(struct device *dev,
95 struct device_attribute *da, char *buf)
97 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
98 struct regmap *regmap = dev_get_drvdata(dev);
102 ret = regmap_read(regmap, LTC4260_FAULT, &fault);
106 fault &= attr->index;
107 if (fault) /* Clear reported faults in chip register */
108 regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);
110 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
114 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE);
115 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN);
119 * UV/OV faults are associated with the input voltage, and the POWER BAD and
120 * FET SHORT faults are associated with the output voltage.
122 static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV);
123 static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV);
124 static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool,
125 FAULT_POWER_BAD | FAULT_FET_SHORT);
127 /* Current (via sense resistor) */
128 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE);
130 /* Overcurrent alarm */
131 static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC);
133 static struct attribute *ltc4260_attrs[] = {
134 &sensor_dev_attr_in1_input.dev_attr.attr,
135 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
136 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
137 &sensor_dev_attr_in2_input.dev_attr.attr,
138 &sensor_dev_attr_in2_alarm.dev_attr.attr,
140 &sensor_dev_attr_curr1_input.dev_attr.attr,
141 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
145 ATTRIBUTE_GROUPS(ltc4260);
147 static const struct regmap_config ltc4260_regmap_config = {
150 .max_register = LTC4260_ADIN,
153 static int ltc4260_probe(struct i2c_client *client,
154 const struct i2c_device_id *id)
156 struct device *dev = &client->dev;
157 struct device *hwmon_dev;
158 struct regmap *regmap;
160 regmap = devm_regmap_init_i2c(client, <c4260_regmap_config);
161 if (IS_ERR(regmap)) {
162 dev_err(dev, "failed to allocate register map\n");
163 return PTR_ERR(regmap);
167 regmap_write(regmap, LTC4260_FAULT, 0x00);
169 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
172 return PTR_ERR_OR_ZERO(hwmon_dev);
175 static const struct i2c_device_id ltc4260_id[] = {
180 MODULE_DEVICE_TABLE(i2c, ltc4260_id);
182 static struct i2c_driver ltc4260_driver = {
186 .probe = ltc4260_probe,
187 .id_table = ltc4260_id,
190 module_i2c_driver(ltc4260_driver);
192 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
193 MODULE_DESCRIPTION("LTC4260 driver");
194 MODULE_LICENSE("GPL");