drivers/hwmon/lm92.c

   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");