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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 | ||
153 | static struct regmap_config ltc4260_regmap_config = { | |
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"); |