1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * lm92 - Hardware monitoring driver
4 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
5 *
6 * Based on the lm90 driver, with some ideas taken from the lm_sensors
7 * lm92 driver as well.
8 *
9 * The LM92 is a sensor chip made by National Semiconductor. It reports
10 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
11 * accuracy. Complete datasheet can be obtained from National's website
12 * at:
13 * http://www.national.com/pf/LM/LM92.html
14 *
15 * This driver also supports the MAX6635 sensor chip made by Maxim.
16 * This chip is compatible with the LM92, but has a lesser accuracy
17 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * at:
19 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 *
21 * Since the LM92 was the first chipset supported by this driver, most
22 * comments will refer to this chipset, but are actually general and
23 * concern all supported chipsets, unless mentioned otherwise.
24 *
25 * Support could easily be added for the National Semiconductor LM76
26 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
27 * with the LM92.
28 */
29
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/slab.h>
33 #include <linux/i2c.h>
34 #include <linux/hwmon.h>
35 #include <linux/hwmon-sysfs.h>
36 #include <linux/err.h>
37 #include <linux/mutex.h>
38 #include <linux/jiffies.h>
39
40 /*
41 * The LM92 and MAX6635 have 2 two-state pins for address selection,
42 * resulting in 4 possible addresses.
43 */
44 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
45 I2C_CLIENT_END };
46 enum chips { lm92, max6635 };
47
48 /* The LM92 registers */
49 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
50 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
51 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
52 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
53 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
54 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
55 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
56
57 /*
58 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
59 * left-justified in 16-bit registers. No rounding is done, with such
60 * a resolution it's just not worth it. Note that the MAX6635 doesn't
61 * make use of the 4 lower bits for limits (i.e. effective resolution
62 * for limits is 1 degree Celsius).
63 */
TEMP_FROM_REG(s16 reg)64 static inline int TEMP_FROM_REG(s16 reg)
65 {
66 return reg / 8 * 625 / 10;
67 }
68
TEMP_TO_REG(long val)69 static inline s16 TEMP_TO_REG(long val)
70 {
71 val = clamp_val(val, -60000, 160000);
72 return val * 10 / 625 * 8;
73 }
74
75 /* Alarm flags are stored in the 3 LSB of the temperature register */
ALARMS_FROM_REG(s16 reg)76 static inline u8 ALARMS_FROM_REG(s16 reg)
77 {
78 return reg & 0x0007;
79 }
80
81 enum temp_index {
82 t_input,
83 t_crit,
84 t_min,
85 t_max,
86 t_hyst,
87 t_num_regs
88 };
89
90 static const u8 regs[t_num_regs] = {
91 [t_input] = LM92_REG_TEMP,
92 [t_crit] = LM92_REG_TEMP_CRIT,
93 [t_min] = LM92_REG_TEMP_LOW,
94 [t_max] = LM92_REG_TEMP_HIGH,
95 [t_hyst] = LM92_REG_TEMP_HYST,
96 };
97
98 /* Client data (each client gets its own) */
99 struct lm92_data {
100 struct i2c_client *client;
101 struct mutex update_lock;
102 char valid; /* zero until following fields are valid */
103 unsigned long last_updated; /* in jiffies */
104
105 /* registers values */
106 s16 temp[t_num_regs]; /* index with enum temp_index */
107 };
108
109 /*
110 * Sysfs attributes and callback functions
111 */
112
lm92_update_device(struct device * dev)113 static struct lm92_data *lm92_update_device(struct device *dev)
114 {
115 struct lm92_data *data = dev_get_drvdata(dev);
116 struct i2c_client *client = data->client;
117 int i;
118
119 mutex_lock(&data->update_lock);
120
121 if (time_after(jiffies, data->last_updated + HZ) ||
122 !data->valid) {
123 dev_dbg(&client->dev, "Updating lm92 data\n");
124 for (i = 0; i < t_num_regs; i++) {
125 data->temp[i] =
126 i2c_smbus_read_word_swapped(client, regs[i]);
127 }
128 data->last_updated = jiffies;
129 data->valid = 1;
130 }
131
132 mutex_unlock(&data->update_lock);
133
134 return data;
135 }
136
temp_show(struct device * dev,struct device_attribute * devattr,char * buf)137 static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
138 char *buf)
139 {
140 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
141 struct lm92_data *data = lm92_update_device(dev);
142
143 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
144 }
145
temp_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)146 static ssize_t temp_store(struct device *dev,
147 struct device_attribute *devattr, const char *buf,
148 size_t count)
149 {
150 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
151 struct lm92_data *data = dev_get_drvdata(dev);
152 struct i2c_client *client = data->client;
153 int nr = attr->index;
154 long val;
155 int err;
156
157 err = kstrtol(buf, 10, &val);
158 if (err)
159 return err;
160
161 mutex_lock(&data->update_lock);
162 data->temp[nr] = TEMP_TO_REG(val);
163 i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
164 mutex_unlock(&data->update_lock);
165 return count;
166 }
167
temp_hyst_show(struct device * dev,struct device_attribute * devattr,char * buf)168 static ssize_t temp_hyst_show(struct device *dev,
169 struct device_attribute *devattr, char *buf)
170 {
171 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
172 struct lm92_data *data = lm92_update_device(dev);
173
174 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
175 - TEMP_FROM_REG(data->temp[t_hyst]));
176 }
177
temp1_min_hyst_show(struct device * dev,struct device_attribute * attr,char * buf)178 static ssize_t temp1_min_hyst_show(struct device *dev,
179 struct device_attribute *attr, char *buf)
180 {
181 struct lm92_data *data = lm92_update_device(dev);
182
183 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
184 + TEMP_FROM_REG(data->temp[t_hyst]));
185 }
186
temp_hyst_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)187 static ssize_t temp_hyst_store(struct device *dev,
188 struct device_attribute *devattr,
189 const char *buf, size_t count)
190 {
191 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
192 struct lm92_data *data = dev_get_drvdata(dev);
193 struct i2c_client *client = data->client;
194 long val;
195 int err;
196
197 err = kstrtol(buf, 10, &val);
198 if (err)
199 return err;
200
201 val = clamp_val(val, -120000, 220000);
202 mutex_lock(&data->update_lock);
203 data->temp[t_hyst] =
204 TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
205 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
206 data->temp[t_hyst]);
207 mutex_unlock(&data->update_lock);
208 return count;
209 }
210
alarms_show(struct device * dev,struct device_attribute * attr,char * buf)211 static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
212 char *buf)
213 {
214 struct lm92_data *data = lm92_update_device(dev);
215
216 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
217 }
218
alarm_show(struct device * dev,struct device_attribute * attr,char * buf)219 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
220 char *buf)
221 {
222 int bitnr = to_sensor_dev_attr(attr)->index;
223 struct lm92_data *data = lm92_update_device(dev);
224 return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
225 }
226
227 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);
228 static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
229 static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
230 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
231 static DEVICE_ATTR_RO(temp1_min_hyst);
232 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);
233 static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);
234 static DEVICE_ATTR_RO(alarms);
235 static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
236 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
237 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);
238
239 /*
240 * Detection and registration
241 */
242
lm92_init_client(struct i2c_client * client)243 static void lm92_init_client(struct i2c_client *client)
244 {
245 u8 config;
246
247 /* Start the conversions if needed */
248 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
249 if (config & 0x01)
250 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
251 config & 0xFE);
252 }
253
254 static struct attribute *lm92_attrs[] = {
255 &sensor_dev_attr_temp1_input.dev_attr.attr,
256 &sensor_dev_attr_temp1_crit.dev_attr.attr,
257 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
258 &sensor_dev_attr_temp1_min.dev_attr.attr,
259 &dev_attr_temp1_min_hyst.attr,
260 &sensor_dev_attr_temp1_max.dev_attr.attr,
261 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
262 &dev_attr_alarms.attr,
263 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
264 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
265 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
266 NULL
267 };
268 ATTRIBUTE_GROUPS(lm92);
269
270 /* Return 0 if detection is successful, -ENODEV otherwise */
lm92_detect(struct i2c_client * new_client,struct i2c_board_info * info)271 static int lm92_detect(struct i2c_client *new_client,
272 struct i2c_board_info *info)
273 {
274 struct i2c_adapter *adapter = new_client->adapter;
275 u8 config;
276 u16 man_id;
277
278 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
279 | I2C_FUNC_SMBUS_WORD_DATA))
280 return -ENODEV;
281
282 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
283 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
284
285 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
286 pr_info("lm92: Found National Semiconductor LM92 chip\n");
287 else
288 return -ENODEV;
289
290 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
291
292 return 0;
293 }
294
lm92_probe(struct i2c_client * new_client)295 static int lm92_probe(struct i2c_client *new_client)
296 {
297 struct device *hwmon_dev;
298 struct lm92_data *data;
299
300 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
301 GFP_KERNEL);
302 if (!data)
303 return -ENOMEM;
304
305 data->client = new_client;
306 mutex_init(&data->update_lock);
307
308 /* Initialize the chipset */
309 lm92_init_client(new_client);
310
311 hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
312 new_client->name,
313 data, lm92_groups);
314 return PTR_ERR_OR_ZERO(hwmon_dev);
315 }
316
317 /*
318 * Module and driver stuff
319 */
320
321 static const struct i2c_device_id lm92_id[] = {
322 { "lm92", lm92 },
323 { "max6635", max6635 },
324 { }
325 };
326 MODULE_DEVICE_TABLE(i2c, lm92_id);
327
328 static struct i2c_driver lm92_driver = {
329 .class = I2C_CLASS_HWMON,
330 .driver = {
331 .name = "lm92",
332 },
333 .probe_new = lm92_probe,
334 .id_table = lm92_id,
335 .detect = lm92_detect,
336 .address_list = normal_i2c,
337 };
338
339 module_i2c_driver(lm92_driver);
340
341 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
342 MODULE_DESCRIPTION("LM92/MAX6635 driver");
343 MODULE_LICENSE("GPL");
344
