drivers/hwmon/lm92.c

   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/err.h>
  31 #include <linux/hwmon.h>
  32 #include <linux/i2c.h>
  33 #include <linux/init.h>
  34 #include <linux/module.h>
  35 #include <linux/mutex.h>
  36 #include <linux/regmap.h>
  37 #include <linux/slab.h>
  38
  39 /*
  40  * The LM92 and MAX6635 have 2 two-state pins for address selection,
  41  * resulting in 4 possible addresses.
  42  */
  43 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
  44                                                 I2C_CLIENT_END };
  45 /* The LM92 registers */
  46 #define LM92_REG_CONFIG                 0x01 /* 8-bit, RW */
  47 #define LM92_REG_TEMP                   0x00 /* 16-bit, RO */
  48 #define LM92_REG_TEMP_HYST              0x02 /* 16-bit, RW */
  49 #define LM92_REG_TEMP_CRIT              0x03 /* 16-bit, RW */
  50 #define LM92_REG_TEMP_LOW               0x04 /* 16-bit, RW */
  51 #define LM92_REG_TEMP_HIGH              0x05 /* 16-bit, RW */
  52 #define LM92_REG_MAN_ID                 0x07 /* 16-bit, RO, LM92 only */
  53
  54 /*
  55  * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
  56  * left-justified in 16-bit registers. No rounding is done, with such
  57  * a resolution it's just not worth it. Note that the MAX6635 doesn't
  58  * make use of the 4 lower bits for limits (i.e. effective resolution
  59  * for limits is 1 degree Celsius).
  60  */
  61 static inline int TEMP_FROM_REG(s16 reg)
  62 {
  63         return reg / 8 * 625 / 10;
  64 }
  65
  66 static inline s16 TEMP_TO_REG(long val, int resolution)
  67 {
  68         val = clamp_val(val, -60000, 160000);
  69         return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);
  70 }
  71
  72 /* Alarm flags are stored in the 3 LSB of the temperature register */
  73 static inline u8 ALARMS_FROM_REG(s16 reg)
  74 {
  75         return reg & 0x0007;
  76 }
  77
  78 /* Client data (each client gets its own) */
  79 struct lm92_data {
  80         struct regmap *regmap;
  81         struct mutex update_lock;
  82         int resolution;
  83 };
  84
  85 static int lm92_temp_read(struct lm92_data *data, u32 attr, int channel, long *val)
  86 {
  87         int reg = -1, hyst_reg = -1, alarm_bit = 0;
  88         struct regmap *regmap = data->regmap;
  89         u32 temp;
  90         int ret;
  91
  92         switch (attr) {
  93         case hwmon_temp_input:
  94                 reg = LM92_REG_TEMP;
  95                 break;
  96         case hwmon_temp_min:
  97                 reg = LM92_REG_TEMP_LOW;
  98                 break;
  99         case hwmon_temp_max:
 100                 reg = LM92_REG_TEMP_HIGH;
 101                 break;
 102         case hwmon_temp_crit:
 103                 reg = LM92_REG_TEMP_CRIT;
 104                 break;
 105         case hwmon_temp_min_hyst:
 106                 hyst_reg = LM92_REG_TEMP_LOW;
 107                 break;
 108         case hwmon_temp_max_hyst:
 109                 hyst_reg = LM92_REG_TEMP_HIGH;
 110                 break;
 111         case hwmon_temp_crit_hyst:
 112                 hyst_reg = LM92_REG_TEMP_CRIT;
 113                 break;
 114         case hwmon_temp_min_alarm:
 115                 alarm_bit = 0;
 116                 break;
 117         case hwmon_temp_max_alarm:
 118                 alarm_bit = 1;
 119                 break;
 120         case hwmon_temp_crit_alarm:
 121                 alarm_bit = 2;
 122                 break;
 123         default:
 124                 return -EOPNOTSUPP;
 125         }
 126         if (reg >= 0) {
 127                 ret = regmap_read(regmap, reg, &temp);
 128                 if (ret < 0)
 129                         return ret;
 130                 *val = TEMP_FROM_REG(temp);
 131         } else if (hyst_reg >= 0) {
 132                 u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };
 133                 u16 regvals[2];
 134
 135                 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
 136                 if (ret)
 137                         return ret;
 138                 if (attr == hwmon_temp_min_hyst)
 139                         *val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);
 140                 else
 141                         *val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);
 142         } else {
 143                 ret = regmap_read(regmap, LM92_REG_TEMP, &temp);
 144                 if (ret)
 145                         return ret;
 146                 *val = !!(temp & BIT(alarm_bit));
 147         }
 148         return 0;
 149 }
 150
 151 static int lm92_chip_read(struct lm92_data *data, u32 attr, long *val)
 152 {
 153         u32 temp;
 154         int ret;
 155
 156         switch (attr) {
 157         case hwmon_chip_alarms:
 158                 ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);
 159                 if (ret)
 160                         return ret;
 161                 *val = ALARMS_FROM_REG(temp);
 162                 break;
 163         default:
 164                 return -EOPNOTSUPP;
 165         }
 166         return 0;
 167 }
 168
 169 static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 170                      int channel, long *val)
 171 {
 172         struct lm92_data *data = dev_get_drvdata(dev);
 173
 174         switch (type) {
 175         case hwmon_chip:
 176                 return lm92_chip_read(data, attr, val);
 177         case hwmon_temp:
 178                 return lm92_temp_read(data, attr, channel, val);
 179         default:
 180                 return -EOPNOTSUPP;
 181         }
 182 }
 183
 184 static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)
 185 {
 186         struct regmap *regmap = data->regmap;
 187         int reg, err;
 188         u32 temp;
 189
 190         switch (attr) {
 191         case hwmon_temp_min:
 192                 reg = LM92_REG_TEMP_LOW;
 193                 break;
 194         case hwmon_temp_max:
 195                 reg = LM92_REG_TEMP_HIGH;
 196                 break;
 197         case hwmon_temp_crit:
 198                 reg = LM92_REG_TEMP_CRIT;
 199                 break;
 200         case hwmon_temp_crit_hyst:
 201                 val = clamp_val(val, -120000, 220000);
 202                 mutex_lock(&data->update_lock);
 203                 err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);
 204                 if (err)
 205                         goto unlock;
 206                 val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);
 207                 err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);
 208 unlock:
 209                 mutex_unlock(&data->update_lock);
 210                 return err;
 211         default:
 212                 return -EOPNOTSUPP;
 213         }
 214         return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));
 215 }
 216
 217 static int lm92_write(struct device *dev, enum hwmon_sensor_types type,
 218                       u32 attr, int channel, long val)
 219 {
 220         struct lm92_data *data = dev_get_drvdata(dev);
 221
 222         switch (type) {
 223         case hwmon_temp:
 224                 return lm92_temp_write(data, attr, val);
 225         default:
 226                 return -EOPNOTSUPP;
 227         }
 228 }
 229
 230 static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,
 231                                u32 attr, int channel)
 232 {
 233         switch (type) {
 234         case hwmon_chip:
 235                 switch (attr) {
 236                 case hwmon_chip_alarms:
 237                         return 0444;
 238                 default:
 239                         break;
 240                 }
 241                 break;
 242         case hwmon_temp:
 243                 switch (attr) {
 244                 case hwmon_temp_min:
 245                 case hwmon_temp_max:
 246                 case hwmon_temp_crit:
 247                 case hwmon_temp_crit_hyst:
 248                         return 0644;
 249                 case hwmon_temp_input:
 250                 case hwmon_temp_min_hyst:
 251                 case hwmon_temp_max_hyst:
 252                 case hwmon_temp_min_alarm:
 253                 case hwmon_temp_max_alarm:
 254                 case hwmon_temp_crit_alarm:
 255                         return 0444;
 256                 default:
 257                         break;
 258                 }
 259                 break;
 260         default:
 261                 break;
 262         }
 263         return 0;
 264 }
 265
 266 static const struct hwmon_channel_info * const lm92_info[] = {
 267         HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
 268         HWMON_CHANNEL_INFO(temp,
 269                            HWMON_T_INPUT |
 270                            HWMON_T_MIN | HWMON_T_MIN_HYST |
 271                            HWMON_T_MAX | HWMON_T_MAX_HYST |
 272                            HWMON_T_CRIT | HWMON_T_CRIT_HYST |
 273                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 274                            HWMON_T_CRIT_ALARM),
 275         NULL
 276 };
 277
 278 static const struct hwmon_ops lm92_hwmon_ops = {
 279         .is_visible = lm92_is_visible,
 280         .read = lm92_read,
 281         .write = lm92_write,
 282 };
 283
 284 static const struct hwmon_chip_info lm92_chip_info = {
 285         .ops = &lm92_hwmon_ops,
 286         .info = lm92_info,
 287 };
 288
 289 /*
 290  * Detection and registration
 291  */
 292
 293 static int lm92_init_client(struct regmap *regmap)
 294 {
 295         return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);
 296 }
 297
 298 /* Return 0 if detection is successful, -ENODEV otherwise */
 299 static int lm92_detect(struct i2c_client *new_client,
 300                        struct i2c_board_info *info)
 301 {
 302         struct i2c_adapter *adapter = new_client->adapter;
 303         u8 config_addr = LM92_REG_CONFIG;
 304         u8 man_id_addr = LM92_REG_MAN_ID;
 305         int i, regval;
 306
 307         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 308                                             | I2C_FUNC_SMBUS_WORD_DATA))
 309                 return -ENODEV;
 310
 311         /*
 312          * Register values repeat with multiples of 8.
 313          * Read twice to improve detection accuracy.
 314          */
 315         for (i = 0; i < 2; i++) {
 316                 regval = i2c_smbus_read_word_data(new_client, man_id_addr);
 317                 if (regval != 0x0180)
 318                         return -ENODEV;
 319                 regval = i2c_smbus_read_byte_data(new_client, config_addr);
 320                 if (regval < 0 || (regval & 0xe0))
 321                         return -ENODEV;
 322                 config_addr += 8;
 323                 man_id_addr += 8;
 324         }
 325
 326         strscpy(info->type, "lm92", I2C_NAME_SIZE);
 327
 328         return 0;
 329 }
 330
 331 /* regmap */
 332
 333 static int lm92_reg_read(void *context, unsigned int reg, unsigned int *val)
 334 {
 335         int ret;
 336
 337         if (reg == LM92_REG_CONFIG)
 338                 ret = i2c_smbus_read_byte_data(context, reg);
 339         else
 340                 ret = i2c_smbus_read_word_swapped(context, reg);
 341         if (ret < 0)
 342                 return ret;
 343
 344         *val = ret;
 345         return 0;
 346 }
 347
 348 static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)
 349 {
 350         if (reg == LM92_REG_CONFIG)
 351                 return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);
 352
 353         return i2c_smbus_write_word_swapped(context, reg, val);
 354 }
 355
 356 static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)
 357 {
 358         return reg == LM92_REG_TEMP;
 359 }
 360
 361 static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)
 362 {
 363         return reg >= LM92_REG_CONFIG;
 364 }
 365
 366 static const struct regmap_config lm92_regmap_config = {
 367         .reg_bits = 8,
 368         .val_bits = 16,
 369         .max_register = LM92_REG_TEMP_HIGH,
 370         .cache_type = REGCACHE_MAPLE,
 371         .volatile_reg = lm92_regmap_is_volatile,
 372         .writeable_reg = lm92_regmap_is_writeable,
 373 };
 374
 375 static const struct regmap_bus lm92_regmap_bus = {
 376         .reg_write = lm92_reg_write,
 377         .reg_read = lm92_reg_read,
 378 };
 379
 380 static int lm92_probe(struct i2c_client *client)
 381 {
 382         struct device *dev = &client->dev;
 383         struct device *hwmon_dev;
 384         struct lm92_data *data;
 385         struct regmap *regmap;
 386         int err;
 387
 388         regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,
 389                                   &lm92_regmap_config);
 390         if (IS_ERR(regmap))
 391                 return PTR_ERR(regmap);
 392
 393         data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);
 394         if (!data)
 395                 return -ENOMEM;
 396
 397         data->regmap = regmap;
 398         data->resolution = (unsigned long)i2c_get_match_data(client);
 399         mutex_init(&data->update_lock);
 400
 401         /* Initialize the chipset */
 402         err = lm92_init_client(regmap);
 403         if (err)
 404                 return err;
 405
 406         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
 407                                                          &lm92_chip_info, NULL);
 408         return PTR_ERR_OR_ZERO(hwmon_dev);
 409 }
 410
 411 /*
 412  * Module and driver stuff
 413  */
 414
 415 /* .driver_data is limit register resolution */
 416 static const struct i2c_device_id lm92_id[] = {
 417         { "lm92", 13 },
 418         { "max6635", 9 },
 419         { }
 420 };
 421 MODULE_DEVICE_TABLE(i2c, lm92_id);
 422
 423 static struct i2c_driver lm92_driver = {
 424         .class          = I2C_CLASS_HWMON,
 425         .driver = {
 426                 .name   = "lm92",
 427         },
 428         .probe          = lm92_probe,
 429         .id_table       = lm92_id,
 430         .detect         = lm92_detect,
 431         .address_list   = normal_i2c,
 432 };
 433
 434 module_i2c_driver(lm92_driver);
 435
 436 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 437 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 438 MODULE_LICENSE("GPL");