1 /* tmp421.c
2 *
3 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
4 * Preliminary support by:
5 * Melvin Rook, Raymond Ng
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22 /*
23 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
24 * Supported models: TMP421, TMP422, TMP423
25 */
26
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/slab.h>
30 #include <linux/jiffies.h>
31 #include <linux/i2c.h>
32 #include <linux/hwmon.h>
33 #include <linux/hwmon-sysfs.h>
34 #include <linux/err.h>
35 #include <linux/mutex.h>
36 #include <linux/sysfs.h>
37
38 /* Addresses to scan */
39 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
40 I2C_CLIENT_END };
41
42 enum chips { tmp421, tmp422, tmp423 };
43
44 /* The TMP421 registers */
45 #define TMP421_CONFIG_REG_1 0x09
46 #define TMP421_CONVERSION_RATE_REG 0x0B
47 #define TMP421_MANUFACTURER_ID_REG 0xFE
48 #define TMP421_DEVICE_ID_REG 0xFF
49
50 static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
51 static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
52
53 /* Flags */
54 #define TMP421_CONFIG_SHUTDOWN 0x40
55 #define TMP421_CONFIG_RANGE 0x04
56
57 /* Manufacturer / Device ID's */
58 #define TMP421_MANUFACTURER_ID 0x55
59 #define TMP421_DEVICE_ID 0x21
60 #define TMP422_DEVICE_ID 0x22
61 #define TMP423_DEVICE_ID 0x23
62
63 static const struct i2c_device_id tmp421_id[] = {
64 { "tmp421", 2 },
65 { "tmp422", 3 },
66 { "tmp423", 4 },
67 { }
68 };
69 MODULE_DEVICE_TABLE(i2c, tmp421_id);
70
71 struct tmp421_data {
72 struct device *hwmon_dev;
73 struct mutex update_lock;
74 char valid;
75 unsigned long last_updated;
76 int channels;
77 u8 config;
78 s16 temp[4];
79 };
80
temp_from_s16(s16 reg)81 static int temp_from_s16(s16 reg)
82 {
83 /* Mask out status bits */
84 int temp = reg & ~0xf;
85
86 return (temp * 1000 + 128) / 256;
87 }
88
temp_from_u16(u16 reg)89 static int temp_from_u16(u16 reg)
90 {
91 /* Mask out status bits */
92 int temp = reg & ~0xf;
93
94 /* Add offset for extended temperature range. */
95 temp -= 64 * 256;
96
97 return (temp * 1000 + 128) / 256;
98 }
99
tmp421_update_device(struct device * dev)100 static struct tmp421_data *tmp421_update_device(struct device *dev)
101 {
102 struct i2c_client *client = to_i2c_client(dev);
103 struct tmp421_data *data = i2c_get_clientdata(client);
104 int i;
105
106 mutex_lock(&data->update_lock);
107
108 if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
109 data->config = i2c_smbus_read_byte_data(client,
110 TMP421_CONFIG_REG_1);
111
112 for (i = 0; i < data->channels; i++) {
113 data->temp[i] = i2c_smbus_read_byte_data(client,
114 TMP421_TEMP_MSB[i]) << 8;
115 data->temp[i] |= i2c_smbus_read_byte_data(client,
116 TMP421_TEMP_LSB[i]);
117 }
118 data->last_updated = jiffies;
119 data->valid = 1;
120 }
121
122 mutex_unlock(&data->update_lock);
123
124 return data;
125 }
126
show_temp_value(struct device * dev,struct device_attribute * devattr,char * buf)127 static ssize_t show_temp_value(struct device *dev,
128 struct device_attribute *devattr, char *buf)
129 {
130 int index = to_sensor_dev_attr(devattr)->index;
131 struct tmp421_data *data = tmp421_update_device(dev);
132 int temp;
133
134 mutex_lock(&data->update_lock);
135 if (data->config & TMP421_CONFIG_RANGE)
136 temp = temp_from_u16(data->temp[index]);
137 else
138 temp = temp_from_s16(data->temp[index]);
139 mutex_unlock(&data->update_lock);
140
141 return sprintf(buf, "%d\n", temp);
142 }
143
show_fault(struct device * dev,struct device_attribute * devattr,char * buf)144 static ssize_t show_fault(struct device *dev,
145 struct device_attribute *devattr, char *buf)
146 {
147 int index = to_sensor_dev_attr(devattr)->index;
148 struct tmp421_data *data = tmp421_update_device(dev);
149
150 /*
151 * The OPEN bit signals a fault. This is bit 0 of the temperature
152 * register (low byte).
153 */
154 if (data->temp[index] & 0x01)
155 return sprintf(buf, "1\n");
156 else
157 return sprintf(buf, "0\n");
158 }
159
tmp421_is_visible(struct kobject * kobj,struct attribute * a,int n)160 static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
161 int n)
162 {
163 struct device *dev = container_of(kobj, struct device, kobj);
164 struct tmp421_data *data = dev_get_drvdata(dev);
165 struct device_attribute *devattr;
166 unsigned int index;
167
168 devattr = container_of(a, struct device_attribute, attr);
169 index = to_sensor_dev_attr(devattr)->index;
170
171 if (index < data->channels)
172 return a->mode;
173
174 return 0;
175 }
176
177 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
178 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
179 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
180 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
181 static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
182 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
183 static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
184
185 static struct attribute *tmp421_attr[] = {
186 &sensor_dev_attr_temp1_input.dev_attr.attr,
187 &sensor_dev_attr_temp2_input.dev_attr.attr,
188 &sensor_dev_attr_temp2_fault.dev_attr.attr,
189 &sensor_dev_attr_temp3_input.dev_attr.attr,
190 &sensor_dev_attr_temp3_fault.dev_attr.attr,
191 &sensor_dev_attr_temp4_input.dev_attr.attr,
192 &sensor_dev_attr_temp4_fault.dev_attr.attr,
193 NULL
194 };
195
196 static const struct attribute_group tmp421_group = {
197 .attrs = tmp421_attr,
198 .is_visible = tmp421_is_visible,
199 };
200
tmp421_init_client(struct i2c_client * client)201 static int tmp421_init_client(struct i2c_client *client)
202 {
203 int config, config_orig;
204
205 /* Set the conversion rate to 2 Hz */
206 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
207
208 /* Start conversions (disable shutdown if necessary) */
209 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
210 if (config < 0) {
211 dev_err(&client->dev, "Could not read configuration"
212 " register (%d)\n", config);
213 return -ENODEV;
214 }
215
216 config_orig = config;
217 config &= ~TMP421_CONFIG_SHUTDOWN;
218
219 if (config != config_orig) {
220 dev_info(&client->dev, "Enable monitoring chip\n");
221 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
222 }
223
224 return 0;
225 }
226
tmp421_detect(struct i2c_client * client,struct i2c_board_info * info)227 static int tmp421_detect(struct i2c_client *client,
228 struct i2c_board_info *info)
229 {
230 enum chips kind;
231 struct i2c_adapter *adapter = client->adapter;
232 const char *names[] = { "TMP421", "TMP422", "TMP423" };
233 u8 reg;
234
235 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
236 return -ENODEV;
237
238 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
239 if (reg != TMP421_MANUFACTURER_ID)
240 return -ENODEV;
241
242 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
243 switch (reg) {
244 case TMP421_DEVICE_ID:
245 kind = tmp421;
246 break;
247 case TMP422_DEVICE_ID:
248 kind = tmp422;
249 break;
250 case TMP423_DEVICE_ID:
251 kind = tmp423;
252 break;
253 default:
254 return -ENODEV;
255 }
256
257 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
258 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
259 names[kind], client->addr);
260
261 return 0;
262 }
263
tmp421_probe(struct i2c_client * client,const struct i2c_device_id * id)264 static int tmp421_probe(struct i2c_client *client,
265 const struct i2c_device_id *id)
266 {
267 struct tmp421_data *data;
268 int err;
269
270 data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
271 if (!data)
272 return -ENOMEM;
273
274 i2c_set_clientdata(client, data);
275 mutex_init(&data->update_lock);
276 data->channels = id->driver_data;
277
278 err = tmp421_init_client(client);
279 if (err)
280 goto exit_free;
281
282 err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
283 if (err)
284 goto exit_free;
285
286 data->hwmon_dev = hwmon_device_register(&client->dev);
287 if (IS_ERR(data->hwmon_dev)) {
288 err = PTR_ERR(data->hwmon_dev);
289 data->hwmon_dev = NULL;
290 goto exit_remove;
291 }
292 return 0;
293
294 exit_remove:
295 sysfs_remove_group(&client->dev.kobj, &tmp421_group);
296
297 exit_free:
298 kfree(data);
299
300 return err;
301 }
302
tmp421_remove(struct i2c_client * client)303 static int tmp421_remove(struct i2c_client *client)
304 {
305 struct tmp421_data *data = i2c_get_clientdata(client);
306
307 hwmon_device_unregister(data->hwmon_dev);
308 sysfs_remove_group(&client->dev.kobj, &tmp421_group);
309
310 kfree(data);
311
312 return 0;
313 }
314
315 static struct i2c_driver tmp421_driver = {
316 .class = I2C_CLASS_HWMON,
317 .driver = {
318 .name = "tmp421",
319 },
320 .probe = tmp421_probe,
321 .remove = tmp421_remove,
322 .id_table = tmp421_id,
323 .detect = tmp421_detect,
324 .address_list = normal_i2c,
325 };
326
tmp421_init(void)327 static int __init tmp421_init(void)
328 {
329 return i2c_add_driver(&tmp421_driver);
330 }
331
tmp421_exit(void)332 static void __exit tmp421_exit(void)
333 {
334 i2c_del_driver(&tmp421_driver);
335 }
336
337 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
338 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
339 " driver");
340 MODULE_LICENSE("GPL");
341
342 module_init(tmp421_init);
343 module_exit(tmp421_exit);
344