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
18/*
19 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
20 * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
21 */
22
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/slab.h>
26#include <linux/jiffies.h>
27#include <linux/i2c.h>
28#include <linux/hwmon.h>
29#include <linux/hwmon-sysfs.h>
30#include <linux/err.h>
31#include <linux/mutex.h>
32#include <linux/of_device.h>
33#include <linux/sysfs.h>
34
35/* Addresses to scan */
36static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
37 I2C_CLIENT_END };
38
39enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
40
41/* The TMP421 registers */
42#define TMP421_STATUS_REG 0x08
43#define TMP421_CONFIG_REG_1 0x09
44#define TMP421_CONVERSION_RATE_REG 0x0B
45#define TMP421_MANUFACTURER_ID_REG 0xFE
46#define TMP421_DEVICE_ID_REG 0xFF
47
48static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
49static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
50
51/* Flags */
52#define TMP421_CONFIG_SHUTDOWN 0x40
53#define TMP421_CONFIG_RANGE 0x04
54
55/* Manufacturer / Device ID's */
56#define TMP421_MANUFACTURER_ID 0x55
57#define TMP421_DEVICE_ID 0x21
58#define TMP422_DEVICE_ID 0x22
59#define TMP423_DEVICE_ID 0x23
60#define TMP441_DEVICE_ID 0x41
61#define TMP442_DEVICE_ID 0x42
62
63static const struct i2c_device_id tmp421_id[] = {
64 { "tmp421", 2 },
65 { "tmp422", 3 },
66 { "tmp423", 4 },
67 { "tmp441", 2 },
68 { "tmp442", 3 },
69 { }
70};
71MODULE_DEVICE_TABLE(i2c, tmp421_id);
72
73static const struct of_device_id tmp421_of_match[] = {
74 {
75 .compatible = "ti,tmp421",
76 .data = (void *)2
77 },
78 {
79 .compatible = "ti,tmp422",
80 .data = (void *)3
81 },
82 {
83 .compatible = "ti,tmp423",
84 .data = (void *)4
85 },
86 {
87 .compatible = "ti,tmp441",
88 .data = (void *)2
89 },
90 {
91 .compatible = "ti,tmp442",
92 .data = (void *)3
93 },
94 { },
95};
96MODULE_DEVICE_TABLE(of, tmp421_of_match);
97
98struct tmp421_data {
99 struct i2c_client *client;
100 struct mutex update_lock;
101 u32 temp_config[5];
102 struct hwmon_channel_info temp_info;
103 const struct hwmon_channel_info *info[2];
104 struct hwmon_chip_info chip;
105 char valid;
106 unsigned long last_updated;
107 unsigned long channels;
108 u8 config;
109 s16 temp[4];
110};
111
112static int temp_from_s16(s16 reg)
113{
114 /* Mask out status bits */
115 int temp = reg & ~0xf;
116
117 return (temp * 1000 + 128) / 256;
118}
119
120static int temp_from_u16(u16 reg)
121{
122 /* Mask out status bits */
123 int temp = reg & ~0xf;
124
125 /* Add offset for extended temperature range. */
126 temp -= 64 * 256;
127
128 return (temp * 1000 + 128) / 256;
129}
130
131static struct tmp421_data *tmp421_update_device(struct device *dev)
132{
133 struct tmp421_data *data = dev_get_drvdata(dev);
134 struct i2c_client *client = data->client;
135 int i;
136
137 mutex_lock(&data->update_lock);
138
139 if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
140 data->config = i2c_smbus_read_byte_data(client,
141 TMP421_CONFIG_REG_1);
142
143 for (i = 0; i < data->channels; i++) {
144 data->temp[i] = i2c_smbus_read_byte_data(client,
145 TMP421_TEMP_MSB[i]) << 8;
146 data->temp[i] |= i2c_smbus_read_byte_data(client,
147 TMP421_TEMP_LSB[i]);
148 }
149 data->last_updated = jiffies;
150 data->valid = 1;
151 }
152
153 mutex_unlock(&data->update_lock);
154
155 return data;
156}
157
158static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
159 u32 attr, int channel, long *val)
160{
161 struct tmp421_data *tmp421 = tmp421_update_device(dev);
162
163 switch (attr) {
164 case hwmon_temp_input:
165 if (tmp421->config & TMP421_CONFIG_RANGE)
166 *val = temp_from_u16(tmp421->temp[channel]);
167 else
168 *val = temp_from_s16(tmp421->temp[channel]);
169 return 0;
170 case hwmon_temp_fault:
171 /*
172 * The OPEN bit signals a fault. This is bit 0 of the temperature
173 * register (low byte).
174 */
175 *val = tmp421->temp[channel] & 0x01;
176 return 0;
177 default:
178 return -EOPNOTSUPP;
179 }
180
181}
182
183static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
184 u32 attr, int channel)
185{
186 switch (attr) {
187 case hwmon_temp_fault:
188 if (channel == 0)
189 return 0;
190 return 0444;
191 case hwmon_temp_input:
192 return 0444;
193 default:
194 return 0;
195 }
196}
197
198static int tmp421_init_client(struct i2c_client *client)
199{
200 int config, config_orig;
201
202 /* Set the conversion rate to 2 Hz */
203 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
204
205 /* Start conversions (disable shutdown if necessary) */
206 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
207 if (config < 0) {
208 dev_err(&client->dev,
209 "Could not read configuration register (%d)\n", config);
210 return config;
211 }
212
213 config_orig = config;
214 config &= ~TMP421_CONFIG_SHUTDOWN;
215
216 if (config != config_orig) {
217 dev_info(&client->dev, "Enable monitoring chip\n");
218 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
219 }
220
221 return 0;
222}
223
224static int tmp421_detect(struct i2c_client *client,
225 struct i2c_board_info *info)
226{
227 enum chips kind;
228 struct i2c_adapter *adapter = client->adapter;
229 static const char * const names[] = {
230 "TMP421", "TMP422", "TMP423",
231 "TMP441", "TMP442"
232 };
233 int addr = client->addr;
234 u8 reg;
235
236 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
237 return -ENODEV;
238
239 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
240 if (reg != TMP421_MANUFACTURER_ID)
241 return -ENODEV;
242
243 reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
244 if (reg & 0xf8)
245 return -ENODEV;
246
247 reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
248 if (reg & 0x7f)
249 return -ENODEV;
250
251 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
252 switch (reg) {
253 case TMP421_DEVICE_ID:
254 kind = tmp421;
255 break;
256 case TMP422_DEVICE_ID:
257 if (addr == 0x2a)
258 return -ENODEV;
259 kind = tmp422;
260 break;
261 case TMP423_DEVICE_ID:
262 if (addr != 0x4c && addr != 0x4d)
263 return -ENODEV;
264 kind = tmp423;
265 break;
266 case TMP441_DEVICE_ID:
267 kind = tmp441;
268 break;
269 case TMP442_DEVICE_ID:
270 if (addr != 0x4c && addr != 0x4d)
271 return -ENODEV;
272 kind = tmp442;
273 break;
274 default:
275 return -ENODEV;
276 }
277
278 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
279 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
280 names[kind], client->addr);
281
282 return 0;
283}
284
285static const struct hwmon_ops tmp421_ops = {
286 .is_visible = tmp421_is_visible,
287 .read = tmp421_read,
288};
289
290static int tmp421_probe(struct i2c_client *client,
291 const struct i2c_device_id *id)
292{
293 struct device *dev = &client->dev;
294 struct device *hwmon_dev;
295 struct tmp421_data *data;
296 int i, err;
297
298 data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
299 if (!data)
300 return -ENOMEM;
301
302 mutex_init(&data->update_lock);
303 if (client->dev.of_node)
304 data->channels = (unsigned long)
305 of_device_get_match_data(&client->dev);
306 else
307 data->channels = id->driver_data;
308 data->client = client;
309
310 err = tmp421_init_client(client);
311 if (err)
312 return err;
313
314 for (i = 0; i < data->channels; i++)
315 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
316
317 data->chip.ops = &tmp421_ops;
318 data->chip.info = data->info;
319
320 data->info[0] = &data->temp_info;
321
322 data->temp_info.type = hwmon_temp;
323 data->temp_info.config = data->temp_config;
324
325 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
326 data,
327 &data->chip,
328 NULL);
329 return PTR_ERR_OR_ZERO(hwmon_dev);
330}
331
332static struct i2c_driver tmp421_driver = {
333 .class = I2C_CLASS_HWMON,
334 .driver = {
335 .name = "tmp421",
336 .of_match_table = of_match_ptr(tmp421_of_match),
337 },
338 .probe = tmp421_probe,
339 .id_table = tmp421_id,
340 .detect = tmp421_detect,
341 .address_list = normal_i2c,
342};
343
344module_i2c_driver(tmp421_driver);
345
346MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
347MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
348MODULE_LICENSE("GPL");
349