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 */ 53 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 54 I2C_CLIENT_END }; 55 enum 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 */ 73 static inline int TEMP_FROM_REG(s16 reg) 74 { 75 return reg / 8 * 625 / 10; 76 } 77 78 static 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 */ 85 static inline u8 ALARMS_FROM_REG(s16 reg) 86 { 87 return reg & 0x0007; 88 } 89 90 enum temp_index { 91 t_input, 92 t_crit, 93 t_min, 94 t_max, 95 t_hyst, 96 t_num_regs 97 }; 98 99 static 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) */ 108 struct 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 */ 121 122 static 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 } 145 146 static ssize_t show_temp(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 } 154 155 static ssize_t set_temp(struct device *dev, struct device_attribute *devattr, 156 const char *buf, size_t count) 157 { 158 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 159 struct lm92_data *data = dev_get_drvdata(dev); 160 struct i2c_client *client = data->client; 161 int nr = attr->index; 162 long val; 163 int err; 164 165 err = kstrtol(buf, 10, &val); 166 if (err) 167 return err; 168 169 mutex_lock(&data->update_lock); 170 data->temp[nr] = TEMP_TO_REG(val); 171 i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]); 172 mutex_unlock(&data->update_lock); 173 return count; 174 } 175 176 static ssize_t show_temp_hyst(struct device *dev, 177 struct device_attribute *devattr, char *buf) 178 { 179 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 180 struct lm92_data *data = lm92_update_device(dev); 181 182 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]) 183 - TEMP_FROM_REG(data->temp[t_hyst])); 184 } 185 186 static ssize_t temp1_min_hyst_show(struct device *dev, 187 struct device_attribute *attr, char *buf) 188 { 189 struct lm92_data *data = lm92_update_device(dev); 190 191 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min]) 192 + TEMP_FROM_REG(data->temp[t_hyst])); 193 } 194 195 static ssize_t set_temp_hyst(struct device *dev, 196 struct device_attribute *devattr, 197 const char *buf, size_t count) 198 { 199 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 200 struct lm92_data *data = dev_get_drvdata(dev); 201 struct i2c_client *client = data->client; 202 long val; 203 int err; 204 205 err = kstrtol(buf, 10, &val); 206 if (err) 207 return err; 208 209 val = clamp_val(val, -120000, 220000); 210 mutex_lock(&data->update_lock); 211 data->temp[t_hyst] = 212 TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val); 213 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, 214 data->temp[t_hyst]); 215 mutex_unlock(&data->update_lock); 216 return count; 217 } 218 219 static ssize_t alarms_show(struct device *dev, struct device_attribute *attr, 220 char *buf) 221 { 222 struct lm92_data *data = lm92_update_device(dev); 223 224 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input])); 225 } 226 227 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 228 char *buf) 229 { 230 int bitnr = to_sensor_dev_attr(attr)->index; 231 struct lm92_data *data = lm92_update_device(dev); 232 return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1); 233 } 234 235 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input); 236 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp, 237 t_crit); 238 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, 239 set_temp_hyst, t_crit); 240 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 241 t_min); 242 static DEVICE_ATTR_RO(temp1_min_hyst); 243 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 244 t_max); 245 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max); 246 static DEVICE_ATTR_RO(alarms); 247 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 248 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 249 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 250 251 /* 252 * Detection and registration 253 */ 254 255 static void lm92_init_client(struct i2c_client *client) 256 { 257 u8 config; 258 259 /* Start the conversions if needed */ 260 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 261 if (config & 0x01) 262 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 263 config & 0xFE); 264 } 265 266 static struct attribute *lm92_attrs[] = { 267 &sensor_dev_attr_temp1_input.dev_attr.attr, 268 &sensor_dev_attr_temp1_crit.dev_attr.attr, 269 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, 270 &sensor_dev_attr_temp1_min.dev_attr.attr, 271 &dev_attr_temp1_min_hyst.attr, 272 &sensor_dev_attr_temp1_max.dev_attr.attr, 273 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 274 &dev_attr_alarms.attr, 275 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 276 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 277 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 278 NULL 279 }; 280 ATTRIBUTE_GROUPS(lm92); 281 282 /* Return 0 if detection is successful, -ENODEV otherwise */ 283 static int lm92_detect(struct i2c_client *new_client, 284 struct i2c_board_info *info) 285 { 286 struct i2c_adapter *adapter = new_client->adapter; 287 u8 config; 288 u16 man_id; 289 290 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 291 | I2C_FUNC_SMBUS_WORD_DATA)) 292 return -ENODEV; 293 294 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG); 295 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID); 296 297 if ((config & 0xe0) == 0x00 && man_id == 0x0180) 298 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 299 else 300 return -ENODEV; 301 302 strlcpy(info->type, "lm92", I2C_NAME_SIZE); 303 304 return 0; 305 } 306 307 static int lm92_probe(struct i2c_client *new_client, 308 const struct i2c_device_id *id) 309 { 310 struct device *hwmon_dev; 311 struct lm92_data *data; 312 313 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data), 314 GFP_KERNEL); 315 if (!data) 316 return -ENOMEM; 317 318 data->client = new_client; 319 mutex_init(&data->update_lock); 320 321 /* Initialize the chipset */ 322 lm92_init_client(new_client); 323 324 hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev, 325 new_client->name, 326 data, lm92_groups); 327 return PTR_ERR_OR_ZERO(hwmon_dev); 328 } 329 330 /* 331 * Module and driver stuff 332 */ 333 334 static const struct i2c_device_id lm92_id[] = { 335 { "lm92", lm92 }, 336 { "max6635", max6635 }, 337 { } 338 }; 339 MODULE_DEVICE_TABLE(i2c, lm92_id); 340 341 static struct i2c_driver lm92_driver = { 342 .class = I2C_CLASS_HWMON, 343 .driver = { 344 .name = "lm92", 345 }, 346 .probe = lm92_probe, 347 .id_table = lm92_id, 348 .detect = lm92_detect, 349 .address_list = normal_i2c, 350 }; 351 352 module_i2c_driver(lm92_driver); 353 354 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); 355 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 356 MODULE_LICENSE("GPL"); 357