drivers/hwmon/w83773g.c

   1 /*
   2  * Copyright (C) 2017 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Driver for the Nuvoton W83773G SMBus temperature sensor IC.
  10  * Supported models: W83773G
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/i2c.h>
  16 #include <linux/hwmon.h>
  17 #include <linux/hwmon-sysfs.h>
  18 #include <linux/err.h>
  19 #include <linux/of_device.h>
  20 #include <linux/regmap.h>
  21
  22 /* W83773 has 3 channels */
  23 #define W83773_CHANNELS                         3
  24
  25 /* The W83773 registers */
  26 #define W83773_CONVERSION_RATE_REG_READ         0x04
  27 #define W83773_CONVERSION_RATE_REG_WRITE        0x0A
  28 #define W83773_MANUFACTURER_ID_REG              0xFE
  29 #define W83773_LOCAL_TEMP                       0x00
  30
  31 static const u8 W83773_STATUS[2] = { 0x02, 0x17 };
  32
  33 static const u8 W83773_TEMP_LSB[2] = { 0x10, 0x25 };
  34 static const u8 W83773_TEMP_MSB[2] = { 0x01, 0x24 };
  35
  36 static const u8 W83773_OFFSET_LSB[2] = { 0x12, 0x16 };
  37 static const u8 W83773_OFFSET_MSB[2] = { 0x11, 0x15 };
  38
  39 /* this is the number of sensors in the device */
  40 static const struct i2c_device_id w83773_id[] = {
  41         { "w83773g" },
  42         { }
  43 };
  44
  45 MODULE_DEVICE_TABLE(i2c, w83773_id);
  46
  47 static const struct of_device_id w83773_of_match[] = {
  48         {
  49                 .compatible = "nuvoton,w83773g"
  50         },
  51         { },
  52 };
  53 MODULE_DEVICE_TABLE(of, w83773_of_match);
  54
  55 static inline long temp_of_local(s8 reg)
  56 {
  57         return reg * 1000;
  58 }
  59
  60 static inline long temp_of_remote(s8 hb, u8 lb)
  61 {
  62         return (hb << 3 | lb >> 5) * 125;
  63 }
  64
  65 static int get_local_temp(struct regmap *regmap, long *val)
  66 {
  67         unsigned int regval;
  68         int ret;
  69
  70         ret = regmap_read(regmap, W83773_LOCAL_TEMP, &regval);
  71         if (ret < 0)
  72                 return ret;
  73
  74         *val = temp_of_local(regval);
  75         return 0;
  76 }
  77
  78 static int get_remote_temp(struct regmap *regmap, int index, long *val)
  79 {
  80         unsigned int regval_high;
  81         unsigned int regval_low;
  82         int ret;
  83
  84         ret = regmap_read(regmap, W83773_TEMP_MSB[index], &regval_high);
  85         if (ret < 0)
  86                 return ret;
  87
  88         ret = regmap_read(regmap, W83773_TEMP_LSB[index], &regval_low);
  89         if (ret < 0)
  90                 return ret;
  91
  92         *val = temp_of_remote(regval_high, regval_low);
  93         return 0;
  94 }
  95
  96 static int get_fault(struct regmap *regmap, int index, long *val)
  97 {
  98         unsigned int regval;
  99         int ret;
 100
 101         ret = regmap_read(regmap, W83773_STATUS[index], &regval);
 102         if (ret < 0)
 103                 return ret;
 104
 105         *val = (regval & 0x04) >> 2;
 106         return 0;
 107 }
 108
 109 static int get_offset(struct regmap *regmap, int index, long *val)
 110 {
 111         unsigned int regval_high;
 112         unsigned int regval_low;
 113         int ret;
 114
 115         ret = regmap_read(regmap, W83773_OFFSET_MSB[index], &regval_high);
 116         if (ret < 0)
 117                 return ret;
 118
 119         ret = regmap_read(regmap, W83773_OFFSET_LSB[index], &regval_low);
 120         if (ret < 0)
 121                 return ret;
 122
 123         *val = temp_of_remote(regval_high, regval_low);
 124         return 0;
 125 }
 126
 127 static int set_offset(struct regmap *regmap, int index, long val)
 128 {
 129         int ret;
 130         u8 high_byte;
 131         u8 low_byte;
 132
 133         val = clamp_val(val, -127825, 127825);
 134         /* offset value equals to (high_byte << 3 | low_byte >> 5) * 125 */
 135         val /= 125;
 136         high_byte = val >> 3;
 137         low_byte = (val & 0x07) << 5;
 138
 139         ret = regmap_write(regmap, W83773_OFFSET_MSB[index], high_byte);
 140         if (ret < 0)
 141                 return ret;
 142
 143         return regmap_write(regmap, W83773_OFFSET_LSB[index], low_byte);
 144 }
 145
 146 static int get_update_interval(struct regmap *regmap, long *val)
 147 {
 148         unsigned int regval;
 149         int ret;
 150
 151         ret = regmap_read(regmap, W83773_CONVERSION_RATE_REG_READ, &regval);
 152         if (ret < 0)
 153                 return ret;
 154
 155         *val = 16000 >> regval;
 156         return 0;
 157 }
 158
 159 static int set_update_interval(struct regmap *regmap, long val)
 160 {
 161         int rate;
 162
 163         /*
 164          * For valid rates, interval can be calculated as
 165          *      interval = (1 << (8 - rate)) * 62.5;
 166          * Rounded rate is therefore
 167          *      rate = 8 - __fls(interval * 8 / (62.5 * 7));
 168          * Use clamp_val() to avoid overflows, and to ensure valid input
 169          * for __fls.
 170          */
 171         val = clamp_val(val, 62, 16000) * 10;
 172         rate = 8 - __fls((val * 8 / (625 * 7)));
 173         return regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, rate);
 174 }
 175
 176 static int w83773_read(struct device *dev, enum hwmon_sensor_types type,
 177                        u32 attr, int channel, long *val)
 178 {
 179         struct regmap *regmap = dev_get_drvdata(dev);
 180
 181         if (type == hwmon_chip) {
 182                 if (attr == hwmon_chip_update_interval)
 183                         return get_update_interval(regmap, val);
 184                 return -EOPNOTSUPP;
 185         }
 186
 187         switch (attr) {
 188         case hwmon_temp_input:
 189                 if (channel == 0)
 190                         return get_local_temp(regmap, val);
 191                 return get_remote_temp(regmap, channel - 1, val);
 192         case hwmon_temp_fault:
 193                 return get_fault(regmap, channel - 1, val);
 194         case hwmon_temp_offset:
 195                 return get_offset(regmap, channel - 1, val);
 196         default:
 197                 return -EOPNOTSUPP;
 198         }
 199 }
 200
 201 static int w83773_write(struct device *dev, enum hwmon_sensor_types type,
 202                         u32 attr, int channel, long val)
 203 {
 204         struct regmap *regmap = dev_get_drvdata(dev);
 205
 206         if (type == hwmon_chip && attr == hwmon_chip_update_interval)
 207                 return set_update_interval(regmap, val);
 208
 209         if (type == hwmon_temp && attr == hwmon_temp_offset)
 210                 return set_offset(regmap, channel - 1, val);
 211
 212         return -EOPNOTSUPP;
 213 }
 214
 215 static umode_t w83773_is_visible(const void *data, enum hwmon_sensor_types type,
 216                                  u32 attr, int channel)
 217 {
 218         switch (type) {
 219         case hwmon_chip:
 220                 switch (attr) {
 221                 case hwmon_chip_update_interval:
 222                         return 0644;
 223                 }
 224                 break;
 225         case hwmon_temp:
 226                 switch (attr) {
 227                 case hwmon_temp_input:
 228                 case hwmon_temp_fault:
 229                         return 0444;
 230                 case hwmon_temp_offset:
 231                         return 0644;
 232                 }
 233                 break;
 234         default:
 235                 break;
 236         }
 237         return 0;
 238 }
 239
 240 static const u32 w83773_chip_config[] = {
 241         HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
 242         0
 243 };
 244
 245 static const struct hwmon_channel_info w83773_chip = {
 246         .type = hwmon_chip,
 247         .config = w83773_chip_config,
 248 };
 249
 250 static const u32 w83773_temp_config[] = {
 251         HWMON_T_INPUT,
 252         HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
 253         HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
 254         0
 255 };
 256
 257 static const struct hwmon_channel_info w83773_temp = {
 258         .type = hwmon_temp,
 259         .config = w83773_temp_config,
 260 };
 261
 262 static const struct hwmon_channel_info *w83773_info[] = {
 263         &w83773_chip,
 264         &w83773_temp,
 265         NULL
 266 };
 267
 268 static const struct hwmon_ops w83773_ops = {
 269         .is_visible = w83773_is_visible,
 270         .read = w83773_read,
 271         .write = w83773_write,
 272 };
 273
 274 static const struct hwmon_chip_info w83773_chip_info = {
 275         .ops = &w83773_ops,
 276         .info = w83773_info,
 277 };
 278
 279 static const struct regmap_config w83773_regmap_config = {
 280         .reg_bits = 8,
 281         .val_bits = 8,
 282 };
 283
 284 static int w83773_probe(struct i2c_client *client,
 285                         const struct i2c_device_id *id)
 286 {
 287         struct device *dev = &client->dev;
 288         struct device *hwmon_dev;
 289         struct regmap *regmap;
 290         int ret;
 291
 292         regmap = devm_regmap_init_i2c(client, &w83773_regmap_config);
 293         if (IS_ERR(regmap)) {
 294                 dev_err(dev, "failed to allocate register map\n");
 295                 return PTR_ERR(regmap);
 296         }
 297
 298         /* Set the conversion rate to 2 Hz */
 299         ret = regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, 0x05);
 300         if (ret < 0) {
 301                 dev_err(&client->dev, "error writing config rate register\n");
 302                 return ret;
 303         }
 304
 305         i2c_set_clientdata(client, regmap);
 306
 307         hwmon_dev = devm_hwmon_device_register_with_info(dev,
 308                                                          client->name,
 309                                                          regmap,
 310                                                          &w83773_chip_info,
 311                                                          NULL);
 312         return PTR_ERR_OR_ZERO(hwmon_dev);
 313 }
 314
 315 static struct i2c_driver w83773_driver = {
 316         .class = I2C_CLASS_HWMON,
 317         .driver = {
 318                 .name   = "w83773g",
 319                 .of_match_table = of_match_ptr(w83773_of_match),
 320         },
 321         .probe = w83773_probe,
 322         .id_table = w83773_id,
 323 };
 324
 325 module_i2c_driver(w83773_driver);
 326
 327 MODULE_AUTHOR("Lei YU <mine260309@gmail.com>");
 328 MODULE_DESCRIPTION("W83773G temperature sensor driver");
 329 MODULE_LICENSE("GPL");