1/*
2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
4 *
5 * Based on the lm90 driver, with some ideas taken from the lm_sensors
6 * lm92 driver as well.
7 *
8 * The LM92 is a sensor chip made by National Semiconductor. It reports
9 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
10 * accuracy. Complete datasheet can be obtained from National's website
11 * at:
12 * http://www.national.com/pf/LM/LM92.html
13 *
14 * This driver also supports the MAX6635 sensor chip made by Maxim.
15 * This chip is compatible with the LM92, but has a lesser accuracy
16 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
17 * at:
18 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
19 *
20 * Since the LM92 was the first chipset supported by this driver, most
21 * comments will refer to this chipset, but are actually general and
22 * concern all supported chipsets, unless mentioned otherwise.
23 *
24 * Support could easily be added for the National Semiconductor LM76
25 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
26 * with the LM92.
27 *
28 * This program is free software; you can redistribute it and/or modify
29 * it under the terms of the GNU General Public License as published by
30 * the Free Software Foundation; either version 2 of the License, or
31 * (at your option) any later version.
32 *
33 * This program is distributed in the hope that it will be useful,
34 * but WITHOUT ANY WARRANTY; without even the implied warranty of
35 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
36 * GNU General Public License for more details.
37 */
38
39#include <linux/module.h>
40#include <linux/init.h>
41#include <linux/slab.h>
42#include <linux/i2c.h>
43#include <linux/hwmon.h>
44#include <linux/hwmon-sysfs.h>
45#include <linux/err.h>
46#include <linux/mutex.h>
47#include <linux/jiffies.h>
48
49/*
50 * The LM92 and MAX6635 have 2 two-state pins for address selection,
51 * resulting in 4 possible addresses.
52 */
53static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
54 I2C_CLIENT_END };
55enum chips { lm92, max6635 };
56
57/* The LM92 registers */
58#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
59#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
60#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
61#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
62#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
63#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
64#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
65
66/*
67 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
68 * left-justified in 16-bit registers. No rounding is done, with such
69 * a resolution it's just not worth it. Note that the MAX6635 doesn't
70 * make use of the 4 lower bits for limits (i.e. effective resolution
71 * for limits is 1 degree Celsius).
72 */
73static inline int TEMP_FROM_REG(s16 reg)
74{
75 return reg / 8 * 625 / 10;
76}
77
78static inline s16 TEMP_TO_REG(long val)
79{
80 val = clamp_val(val, -60000, 160000);
81 return val * 10 / 625 * 8;
82}
83
84/* Alarm flags are stored in the 3 LSB of the temperature register */
85static inline u8 ALARMS_FROM_REG(s16 reg)
86{
87 return reg & 0x0007;
88}
89
90enum temp_index {
91 t_input,
92 t_crit,
93 t_min,
94 t_max,
95 t_hyst,
96 t_num_regs
97};
98
99static const u8 regs[t_num_regs] = {
100 [t_input] = LM92_REG_TEMP,
101 [t_crit] = LM92_REG_TEMP_CRIT,
102 [t_min] = LM92_REG_TEMP_LOW,
103 [t_max] = LM92_REG_TEMP_HIGH,
104 [t_hyst] = LM92_REG_TEMP_HYST,
105};
106
107/* Client data (each client gets its own) */
108struct lm92_data {
109 struct i2c_client *client;
110 struct mutex update_lock;
111 char valid; /* zero until following fields are valid */
112 unsigned long last_updated; /* in jiffies */
113
114 /* registers values */
115 s16 temp[t_num_regs]; /* index with enum temp_index */
116};
117
118/*
119 * Sysfs attributes and callback functions
120 */
121
122static struct lm92_data *lm92_update_device(struct device *dev)
123{
124 struct lm92_data *data = dev_get_drvdata(dev);
125 struct i2c_client *client = data->client;
126 int i;
127
128 mutex_lock(&data->update_lock);
129
130 if (time_after(jiffies, data->last_updated + HZ) ||
131 !data->valid) {
132 dev_dbg(&client->dev, "Updating lm92 data\n");
133 for (i = 0; i < t_num_regs; i++) {
134 data->temp[i] =
135 i2c_smbus_read_word_swapped(client, regs[i]);
136 }
137 data->last_updated = jiffies;
138 data->valid = 1;
139 }
140
141 mutex_unlock(&data->update_lock);
142
143 return data;
144}
145
146static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
147 char *buf)
148{
149 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
150 struct lm92_data *data = lm92_update_device(dev);
151
152 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
153}
154
155static ssize_t temp_store(struct device *dev,
156 struct device_attribute *devattr, const char *buf,
157 size_t count)
158{
159 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
160 struct lm92_data *data = dev_get_drvdata(dev);
161 struct i2c_client *client = data->client;
162 int nr = attr->index;
163 long val;
164 int err;
165
166 err = kstrtol(buf, 10, &val);
167 if (err)
168 return err;
169
170 mutex_lock(&data->update_lock);
171 data->temp[nr] = TEMP_TO_REG(val);
172 i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
173 mutex_unlock(&data->update_lock);
174 return count;
175}
176
177static ssize_t temp_hyst_show(struct device *dev,
178 struct device_attribute *devattr, char *buf)
179{
180 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
181 struct lm92_data *data = lm92_update_device(dev);
182
183 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
184 - TEMP_FROM_REG(data->temp[t_hyst]));
185}
186
187static ssize_t temp1_min_hyst_show(struct device *dev,
188 struct device_attribute *attr, char *buf)
189{
190 struct lm92_data *data = lm92_update_device(dev);
191
192 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
193 + TEMP_FROM_REG(data->temp[t_hyst]));
194}
195
196static ssize_t temp_hyst_store(struct device *dev,
197 struct device_attribute *devattr,
198 const char *buf, size_t count)
199{
200 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
201 struct lm92_data *data = dev_get_drvdata(dev);
202 struct i2c_client *client = data->client;
203 long val;
204 int err;
205
206 err = kstrtol(buf, 10, &val);
207 if (err)
208 return err;
209
210 val = clamp_val(val, -120000, 220000);
211 mutex_lock(&data->update_lock);
212 data->temp[t_hyst] =
213 TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
214 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
215 data->temp[t_hyst]);
216 mutex_unlock(&data->update_lock);
217 return count;
218}
219
220static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
221 char *buf)
222{
223 struct lm92_data *data = lm92_update_device(dev);
224
225 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
226}
227
228static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
229 char *buf)
230{
231 int bitnr = to_sensor_dev_attr(attr)->index;
232 struct lm92_data *data = lm92_update_device(dev);
233 return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
234}
235
236static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);
237static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
238static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
239static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
240static DEVICE_ATTR_RO(temp1_min_hyst);
241static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);
242static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);
243static DEVICE_ATTR_RO(alarms);
244static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
245static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
246static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);
247
248/*
249 * Detection and registration
250 */
251
252static void lm92_init_client(struct i2c_client *client)
253{
254 u8 config;
255
256 /* Start the conversions if needed */
257 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
258 if (config & 0x01)
259 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
260 config & 0xFE);
261}
262
263static struct attribute *lm92_attrs[] = {
264 &sensor_dev_attr_temp1_input.dev_attr.attr,
265 &sensor_dev_attr_temp1_crit.dev_attr.attr,
266 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
267 &sensor_dev_attr_temp1_min.dev_attr.attr,
268 &dev_attr_temp1_min_hyst.attr,
269 &sensor_dev_attr_temp1_max.dev_attr.attr,
270 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
271 &dev_attr_alarms.attr,
272 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
273 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
274 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
275 NULL
276};
277ATTRIBUTE_GROUPS(lm92);
278
279/* Return 0 if detection is successful, -ENODEV otherwise */
280static int lm92_detect(struct i2c_client *new_client,
281 struct i2c_board_info *info)
282{
283 struct i2c_adapter *adapter = new_client->adapter;
284 u8 config;
285 u16 man_id;
286
287 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
288 | I2C_FUNC_SMBUS_WORD_DATA))
289 return -ENODEV;
290
291 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
292 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
293
294 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
295 pr_info("lm92: Found National Semiconductor LM92 chip\n");
296 else
297 return -ENODEV;
298
299 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
300
301 return 0;
302}
303
304static int lm92_probe(struct i2c_client *new_client,
305 const struct i2c_device_id *id)
306{
307 struct device *hwmon_dev;
308 struct lm92_data *data;
309
310 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
311 GFP_KERNEL);
312 if (!data)
313 return -ENOMEM;
314
315 data->client = new_client;
316 mutex_init(&data->update_lock);
317
318 /* Initialize the chipset */
319 lm92_init_client(new_client);
320
321 hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
322 new_client->name,
323 data, lm92_groups);
324 return PTR_ERR_OR_ZERO(hwmon_dev);
325}
326
327/*
328 * Module and driver stuff
329 */
330
331static const struct i2c_device_id lm92_id[] = {
332 { "lm92", lm92 },
333 { "max6635", max6635 },
334 { }
335};
336MODULE_DEVICE_TABLE(i2c, lm92_id);
337
338static struct i2c_driver lm92_driver = {
339 .class = I2C_CLASS_HWMON,
340 .driver = {
341 .name = "lm92",
342 },
343 .probe = lm92_probe,
344 .id_table = lm92_id,
345 .detect = lm92_detect,
346 .address_list = normal_i2c,
347};
348
349module_i2c_driver(lm92_driver);
350
351MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
352MODULE_DESCRIPTION("LM92/MAX6635 driver");
353MODULE_LICENSE("GPL");
354