Commit | Line | Data |
---|---|---|
e5f5c99a GR |
1 | /* |
2 | * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller | |
3 | * | |
4 | * Copyright (C) 2010 Ericsson AB. | |
5 | * | |
6 | * Derived from: | |
7 | * | |
8 | * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller | |
9 | * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu> | |
10 | * | |
11 | * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License as published by | |
15 | * the Free Software Foundation; either version 2 of the License, or | |
16 | * (at your option) any later version. | |
17 | * | |
18 | * This program is distributed in the hope that it will be useful, | |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | * GNU General Public License for more details. | |
22 | * | |
23 | * You should have received a copy of the GNU General Public License | |
24 | * along with this program; if not, write to the Free Software | |
25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
26 | */ | |
27 | ||
28 | #include <linux/kernel.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/err.h> | |
32 | #include <linux/slab.h> | |
33 | #include <linux/i2c.h> | |
34 | #include <linux/hwmon.h> | |
35 | #include <linux/hwmon-sysfs.h> | |
dcd8f392 | 36 | #include <linux/jiffies.h> |
e5f5c99a GR |
37 | |
38 | /* chip registers */ | |
39 | #define LTC4261_STATUS 0x00 /* readonly */ | |
40 | #define LTC4261_FAULT 0x01 | |
41 | #define LTC4261_ALERT 0x02 | |
42 | #define LTC4261_CONTROL 0x03 | |
43 | #define LTC4261_SENSE_H 0x04 | |
44 | #define LTC4261_SENSE_L 0x05 | |
45 | #define LTC4261_ADIN2_H 0x06 | |
46 | #define LTC4261_ADIN2_L 0x07 | |
47 | #define LTC4261_ADIN_H 0x08 | |
48 | #define LTC4261_ADIN_L 0x09 | |
49 | ||
50 | /* | |
51 | * Fault register bits | |
52 | */ | |
53 | #define FAULT_OV (1<<0) | |
54 | #define FAULT_UV (1<<1) | |
55 | #define FAULT_OC (1<<2) | |
56 | ||
57 | struct ltc4261_data { | |
58 | struct device *hwmon_dev; | |
59 | ||
60 | struct mutex update_lock; | |
61 | bool valid; | |
62 | unsigned long last_updated; /* in jiffies */ | |
63 | ||
64 | /* Registers */ | |
65 | u8 regs[10]; | |
66 | }; | |
67 | ||
68 | static struct ltc4261_data *ltc4261_update_device(struct device *dev) | |
69 | { | |
70 | struct i2c_client *client = to_i2c_client(dev); | |
71 | struct ltc4261_data *data = i2c_get_clientdata(client); | |
72 | struct ltc4261_data *ret = data; | |
73 | ||
74 | mutex_lock(&data->update_lock); | |
75 | ||
76 | if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) { | |
77 | int i; | |
78 | ||
79 | /* Read registers -- 0x00 to 0x09 */ | |
80 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { | |
81 | int val; | |
82 | ||
83 | val = i2c_smbus_read_byte_data(client, i); | |
84 | if (unlikely(val < 0)) { | |
85 | dev_dbg(dev, | |
69f8b741 | 86 | "Failed to read ADC value: error %d\n", |
e5f5c99a GR |
87 | val); |
88 | ret = ERR_PTR(val); | |
aac9fe9b | 89 | data->valid = 0; |
e5f5c99a GR |
90 | goto abort; |
91 | } | |
92 | data->regs[i] = val; | |
93 | } | |
94 | data->last_updated = jiffies; | |
95 | data->valid = 1; | |
96 | } | |
97 | abort: | |
98 | mutex_unlock(&data->update_lock); | |
99 | return ret; | |
100 | } | |
101 | ||
102 | /* Return the voltage from the given register in mV or mA */ | |
103 | static int ltc4261_get_value(struct ltc4261_data *data, u8 reg) | |
104 | { | |
105 | u32 val; | |
106 | ||
107 | val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6); | |
108 | ||
109 | switch (reg) { | |
110 | case LTC4261_ADIN_H: | |
111 | case LTC4261_ADIN2_H: | |
112 | /* 2.5mV resolution. Convert to mV. */ | |
113 | val = val * 25 / 10; | |
114 | break; | |
115 | case LTC4261_SENSE_H: | |
116 | /* | |
117 | * 62.5uV resolution. Convert to current as measured with | |
118 | * an 1 mOhm sense resistor, in mA. If a different sense | |
119 | * resistor is installed, calculate the actual current by | |
120 | * dividing the reported current by the sense resistor value | |
121 | * in mOhm. | |
122 | */ | |
123 | val = val * 625 / 10; | |
124 | break; | |
125 | default: | |
126 | /* If we get here, the developer messed up */ | |
127 | WARN_ON_ONCE(1); | |
128 | val = 0; | |
129 | break; | |
130 | } | |
131 | ||
132 | return val; | |
133 | } | |
134 | ||
135 | static ssize_t ltc4261_show_value(struct device *dev, | |
136 | struct device_attribute *da, char *buf) | |
137 | { | |
138 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
139 | struct ltc4261_data *data = ltc4261_update_device(dev); | |
140 | int value; | |
141 | ||
142 | if (IS_ERR(data)) | |
143 | return PTR_ERR(data); | |
144 | ||
145 | value = ltc4261_get_value(data, attr->index); | |
146 | return snprintf(buf, PAGE_SIZE, "%d\n", value); | |
147 | } | |
148 | ||
149 | static ssize_t ltc4261_show_bool(struct device *dev, | |
150 | struct device_attribute *da, char *buf) | |
151 | { | |
152 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
153 | struct i2c_client *client = to_i2c_client(dev); | |
154 | struct ltc4261_data *data = ltc4261_update_device(dev); | |
155 | u8 fault; | |
156 | ||
157 | if (IS_ERR(data)) | |
158 | return PTR_ERR(data); | |
159 | ||
160 | fault = data->regs[LTC4261_FAULT] & attr->index; | |
161 | if (fault) /* Clear reported faults in chip register */ | |
162 | i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault); | |
163 | ||
164 | return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0); | |
165 | } | |
166 | ||
e5f5c99a GR |
167 | /* |
168 | * Input voltages. | |
169 | */ | |
bec24b74 GR |
170 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4261_show_value, NULL, |
171 | LTC4261_ADIN_H); | |
172 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4261_show_value, NULL, | |
173 | LTC4261_ADIN2_H); | |
e5f5c99a GR |
174 | |
175 | /* | |
176 | * Voltage alarms. The chip has only one set of voltage alarm status bits, | |
177 | * triggered by input voltage alarms. In many designs, those alarms are | |
178 | * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin | |
179 | * to the OV pin. ADIN2 is, however, not available on all chip variants. | |
180 | * To ensure that the alarm condition is reported to the user, report it | |
181 | * with both voltage sensors. | |
182 | */ | |
bec24b74 GR |
183 | static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4261_show_bool, NULL, |
184 | FAULT_UV); | |
185 | static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL, | |
186 | FAULT_OV); | |
187 | static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc4261_show_bool, NULL, | |
188 | FAULT_UV); | |
189 | static SENSOR_DEVICE_ATTR(in2_max_alarm, S_IRUGO, ltc4261_show_bool, NULL, | |
190 | FAULT_OV); | |
e5f5c99a GR |
191 | |
192 | /* Currents (via sense resistor) */ | |
bec24b74 GR |
193 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4261_show_value, NULL, |
194 | LTC4261_SENSE_H); | |
e5f5c99a GR |
195 | |
196 | /* Overcurrent alarm */ | |
bec24b74 GR |
197 | static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL, |
198 | FAULT_OC); | |
e5f5c99a GR |
199 | |
200 | static struct attribute *ltc4261_attributes[] = { | |
201 | &sensor_dev_attr_in1_input.dev_attr.attr, | |
202 | &sensor_dev_attr_in1_min_alarm.dev_attr.attr, | |
203 | &sensor_dev_attr_in1_max_alarm.dev_attr.attr, | |
204 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
205 | &sensor_dev_attr_in2_min_alarm.dev_attr.attr, | |
206 | &sensor_dev_attr_in2_max_alarm.dev_attr.attr, | |
207 | ||
208 | &sensor_dev_attr_curr1_input.dev_attr.attr, | |
209 | &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, | |
210 | ||
211 | NULL, | |
212 | }; | |
213 | ||
214 | static const struct attribute_group ltc4261_group = { | |
215 | .attrs = ltc4261_attributes, | |
216 | }; | |
217 | ||
218 | static int ltc4261_probe(struct i2c_client *client, | |
219 | const struct i2c_device_id *id) | |
220 | { | |
221 | struct i2c_adapter *adapter = client->adapter; | |
222 | struct ltc4261_data *data; | |
223 | int ret; | |
224 | ||
225 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
226 | return -ENODEV; | |
227 | ||
228 | if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) { | |
475200c0 | 229 | dev_err(&client->dev, "Failed to read status register\n"); |
e5f5c99a GR |
230 | return -ENODEV; |
231 | } | |
232 | ||
36839287 GR |
233 | data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); |
234 | if (!data) | |
235 | return -ENOMEM; | |
e5f5c99a GR |
236 | |
237 | i2c_set_clientdata(client, data); | |
238 | mutex_init(&data->update_lock); | |
239 | ||
240 | /* Clear faults */ | |
241 | i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00); | |
242 | ||
243 | /* Register sysfs hooks */ | |
244 | ret = sysfs_create_group(&client->dev.kobj, <c4261_group); | |
245 | if (ret) | |
36839287 | 246 | return ret; |
e5f5c99a GR |
247 | |
248 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
249 | if (IS_ERR(data->hwmon_dev)) { | |
250 | ret = PTR_ERR(data->hwmon_dev); | |
251 | goto out_hwmon_device_register; | |
252 | } | |
253 | ||
254 | return 0; | |
255 | ||
256 | out_hwmon_device_register: | |
257 | sysfs_remove_group(&client->dev.kobj, <c4261_group); | |
e5f5c99a GR |
258 | return ret; |
259 | } | |
260 | ||
261 | static int ltc4261_remove(struct i2c_client *client) | |
262 | { | |
263 | struct ltc4261_data *data = i2c_get_clientdata(client); | |
264 | ||
265 | hwmon_device_unregister(data->hwmon_dev); | |
266 | sysfs_remove_group(&client->dev.kobj, <c4261_group); | |
267 | ||
e5f5c99a GR |
268 | return 0; |
269 | } | |
270 | ||
271 | static const struct i2c_device_id ltc4261_id[] = { | |
272 | {"ltc4261", 0}, | |
273 | {} | |
274 | }; | |
275 | ||
276 | MODULE_DEVICE_TABLE(i2c, ltc4261_id); | |
277 | ||
278 | /* This is the driver that will be inserted */ | |
279 | static struct i2c_driver ltc4261_driver = { | |
280 | .driver = { | |
281 | .name = "ltc4261", | |
282 | }, | |
283 | .probe = ltc4261_probe, | |
284 | .remove = ltc4261_remove, | |
285 | .id_table = ltc4261_id, | |
286 | }; | |
287 | ||
f0967eea | 288 | module_i2c_driver(ltc4261_driver); |
e5f5c99a | 289 | |
bb9a80e5 | 290 | MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); |
e5f5c99a GR |
291 | MODULE_DESCRIPTION("LTC4261 driver"); |
292 | MODULE_LICENSE("GPL"); |