drivers/hwmon/pmbus/ltc2978.c

   1 /*
   2  * Hardware monitoring driver for LTC2978 and LTC3880
   3  *
   4  * Copyright (c) 2011 Ericsson AB.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/i2c.h>
  27 #include "pmbus.h"
  28
  29 enum chips { ltc2978, ltc3880 };
  30
  31 /* LTC2978 and LTC3880 */
  32 #define LTC2978_MFR_VOUT_PEAK           0xdd
  33 #define LTC2978_MFR_VIN_PEAK            0xde
  34 #define LTC2978_MFR_TEMPERATURE_PEAK    0xdf
  35 #define LTC2978_MFR_SPECIAL_ID          0xe7
  36
  37 /* LTC2978 only */
  38 #define LTC2978_MFR_VOUT_MIN            0xfb
  39 #define LTC2978_MFR_VIN_MIN             0xfc
  40 #define LTC2978_MFR_TEMPERATURE_MIN     0xfd
  41
  42 /* LTC3880 only */
  43 #define LTC3880_MFR_IOUT_PEAK           0xd7
  44 #define LTC3880_MFR_CLEAR_PEAKS         0xe3
  45 #define LTC3880_MFR_TEMPERATURE2_PEAK   0xf4
  46
  47 #define LTC2978_ID_REV1                 0x0121
  48 #define LTC2978_ID_REV2                 0x0122
  49 #define LTC3880_ID                      0x4000
  50 #define LTC3880_ID_MASK                 0xff00
  51
  52 /*
  53  * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
  54  * happens pretty much each time chip data is updated. Raw peak data therefore
  55  * does not provide much value. To be able to provide useful peak data, keep an
  56  * internal cache of measured peak data, which is only cleared if an explicit
  57  * "clear peak" command is executed for the sensor in question.
  58  */
  59 struct ltc2978_data {
  60         enum chips id;
  61         int vin_min, vin_max;
  62         int temp_min, temp_max;
  63         int vout_min[8], vout_max[8];
  64         int iout_max[2];
  65         int temp2_max[2];
  66         struct pmbus_driver_info info;
  67 };
  68
  69 #define to_ltc2978_data(x)  container_of(x, struct ltc2978_data, info)
  70
  71 static inline int lin11_to_val(int data)
  72 {
  73         s16 e = ((s16)data) >> 11;
  74         s32 m = (((s16)(data << 5)) >> 5);
  75
  76         /*
  77          * mantissa is 10 bit + sign, exponent adds up to 15 bit.
  78          * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
  79          */
  80         e += 6;
  81         return (e < 0 ? m >> -e : m << e);
  82 }
  83
  84 static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
  85                                          int reg)
  86 {
  87         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
  88         struct ltc2978_data *data = to_ltc2978_data(info);
  89         int ret;
  90
  91         switch (reg) {
  92         case PMBUS_VIRT_READ_VIN_MAX:
  93                 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
  94                 if (ret >= 0) {
  95                         if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
  96                                 data->vin_max = ret;
  97                         ret = data->vin_max;
  98                 }
  99                 break;
 100         case PMBUS_VIRT_READ_VOUT_MAX:
 101                 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
 102                 if (ret >= 0) {
 103                         /*
 104                          * VOUT is 16 bit unsigned with fixed exponent,
 105                          * so we can compare it directly
 106                          */
 107                         if (ret > data->vout_max[page])
 108                                 data->vout_max[page] = ret;
 109                         ret = data->vout_max[page];
 110                 }
 111                 break;
 112         case PMBUS_VIRT_READ_TEMP_MAX:
 113                 ret = pmbus_read_word_data(client, page,
 114                                            LTC2978_MFR_TEMPERATURE_PEAK);
 115                 if (ret >= 0) {
 116                         if (lin11_to_val(ret) > lin11_to_val(data->temp_max))
 117                                 data->temp_max = ret;
 118                         ret = data->temp_max;
 119                 }
 120                 break;
 121         case PMBUS_VIRT_RESET_VOUT_HISTORY:
 122         case PMBUS_VIRT_RESET_VIN_HISTORY:
 123         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 124                 ret = 0;
 125                 break;
 126         default:
 127                 ret = -ENODATA;
 128                 break;
 129         }
 130         return ret;
 131 }
 132
 133 static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
 134 {
 135         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 136         struct ltc2978_data *data = to_ltc2978_data(info);
 137         int ret;
 138
 139         switch (reg) {
 140         case PMBUS_VIRT_READ_VIN_MIN:
 141                 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
 142                 if (ret >= 0) {
 143                         if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
 144                                 data->vin_min = ret;
 145                         ret = data->vin_min;
 146                 }
 147                 break;
 148         case PMBUS_VIRT_READ_VOUT_MIN:
 149                 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
 150                 if (ret >= 0) {
 151                         /*
 152                          * VOUT_MIN is known to not be supported on some lots
 153                          * of LTC2978 revision 1, and will return the maximum
 154                          * possible voltage if read. If VOUT_MAX is valid and
 155                          * lower than the reading of VOUT_MIN, use it instead.
 156                          */
 157                         if (data->vout_max[page] && ret > data->vout_max[page])
 158                                 ret = data->vout_max[page];
 159                         if (ret < data->vout_min[page])
 160                                 data->vout_min[page] = ret;
 161                         ret = data->vout_min[page];
 162                 }
 163                 break;
 164         case PMBUS_VIRT_READ_TEMP_MIN:
 165                 ret = pmbus_read_word_data(client, page,
 166                                            LTC2978_MFR_TEMPERATURE_MIN);
 167                 if (ret >= 0) {
 168                         if (lin11_to_val(ret)
 169                             < lin11_to_val(data->temp_min))
 170                                 data->temp_min = ret;
 171                         ret = data->temp_min;
 172                 }
 173                 break;
 174         case PMBUS_VIRT_READ_IOUT_MAX:
 175         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 176         case PMBUS_VIRT_READ_TEMP2_MAX:
 177         case PMBUS_VIRT_RESET_TEMP2_HISTORY:
 178                 ret = -ENXIO;
 179                 break;
 180         default:
 181                 ret = ltc2978_read_word_data_common(client, page, reg);
 182                 break;
 183         }
 184         return ret;
 185 }
 186
 187 static int ltc3880_read_word_data(struct i2c_client *client, int page, int reg)
 188 {
 189         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 190         struct ltc2978_data *data = to_ltc2978_data(info);
 191         int ret;
 192
 193         switch (reg) {
 194         case PMBUS_VIRT_READ_IOUT_MAX:
 195                 ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
 196                 if (ret >= 0) {
 197                         if (lin11_to_val(ret)
 198                             > lin11_to_val(data->iout_max[page]))
 199                                 data->iout_max[page] = ret;
 200                         ret = data->iout_max[page];
 201                 }
 202                 break;
 203         case PMBUS_VIRT_READ_TEMP2_MAX:
 204                 ret = pmbus_read_word_data(client, page,
 205                                            LTC3880_MFR_TEMPERATURE2_PEAK);
 206                 if (ret >= 0) {
 207                         if (lin11_to_val(ret)
 208                             > lin11_to_val(data->temp2_max[page]))
 209                                 data->temp2_max[page] = ret;
 210                         ret = data->temp2_max[page];
 211                 }
 212                 break;
 213         case PMBUS_VIRT_READ_VIN_MIN:
 214         case PMBUS_VIRT_READ_VOUT_MIN:
 215         case PMBUS_VIRT_READ_TEMP_MIN:
 216                 ret = -ENXIO;
 217                 break;
 218         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 219         case PMBUS_VIRT_RESET_TEMP2_HISTORY:
 220                 ret = 0;
 221                 break;
 222         default:
 223                 ret = ltc2978_read_word_data_common(client, page, reg);
 224                 break;
 225         }
 226         return ret;
 227 }
 228
 229 static int ltc2978_clear_peaks(struct i2c_client *client, int page,
 230                                enum chips id)
 231 {
 232         int ret;
 233
 234         if (id == ltc2978)
 235                 ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
 236         else
 237                 ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
 238
 239         return ret;
 240 }
 241
 242 static int ltc2978_write_word_data(struct i2c_client *client, int page,
 243                                     int reg, u16 word)
 244 {
 245         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 246         struct ltc2978_data *data = to_ltc2978_data(info);
 247         int ret;
 248
 249         switch (reg) {
 250         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 251                 data->iout_max[page] = 0x7fff;
 252                 ret = ltc2978_clear_peaks(client, page, data->id);
 253                 break;
 254         case PMBUS_VIRT_RESET_TEMP2_HISTORY:
 255                 data->temp2_max[page] = 0x7fff;
 256                 ret = ltc2978_clear_peaks(client, page, data->id);
 257                 break;
 258         case PMBUS_VIRT_RESET_VOUT_HISTORY:
 259                 data->vout_min[page] = 0xffff;
 260                 data->vout_max[page] = 0;
 261                 ret = ltc2978_clear_peaks(client, page, data->id);
 262                 break;
 263         case PMBUS_VIRT_RESET_VIN_HISTORY:
 264                 data->vin_min = 0x7bff;
 265                 data->vin_max = 0;
 266                 ret = ltc2978_clear_peaks(client, page, data->id);
 267                 break;
 268         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 269                 data->temp_min = 0x7bff;
 270                 data->temp_max = 0x7fff;
 271                 ret = ltc2978_clear_peaks(client, page, data->id);
 272                 break;
 273         default:
 274                 ret = -ENODATA;
 275                 break;
 276         }
 277         return ret;
 278 }
 279
 280 static const struct i2c_device_id ltc2978_id[] = {
 281         {"ltc2978", ltc2978},
 282         {"ltc3880", ltc3880},
 283         {}
 284 };
 285 MODULE_DEVICE_TABLE(i2c, ltc2978_id);
 286
 287 static int ltc2978_probe(struct i2c_client *client,
 288                          const struct i2c_device_id *id)
 289 {
 290         int chip_id, i;
 291         struct ltc2978_data *data;
 292         struct pmbus_driver_info *info;
 293
 294         if (!i2c_check_functionality(client->adapter,
 295                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 296                 return -ENODEV;
 297
 298         data = devm_kzalloc(&client->dev, sizeof(struct ltc2978_data),
 299                             GFP_KERNEL);
 300         if (!data)
 301                 return -ENOMEM;
 302
 303         chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
 304         if (chip_id < 0)
 305                 return chip_id;
 306
 307         if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
 308                 data->id = ltc2978;
 309         } else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
 310                 data->id = ltc3880;
 311         } else {
 312                 dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
 313                 return -ENODEV;
 314         }
 315         if (data->id != id->driver_data)
 316                 dev_warn(&client->dev,
 317                          "Device mismatch: Configured %s, detected %s\n",
 318                          id->name,
 319                          ltc2978_id[data->id].name);
 320
 321         info = &data->info;
 322         info->write_word_data = ltc2978_write_word_data;
 323
 324         data->vout_min[0] = 0xffff;
 325         data->vin_min = 0x7bff;
 326         data->temp_min = 0x7bff;
 327         data->temp_max = 0x7fff;
 328
 329         switch (id->driver_data) {
 330         case ltc2978:
 331                 info->read_word_data = ltc2978_read_word_data;
 332                 info->pages = 8;
 333                 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
 334                   | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 335                   | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
 336                 for (i = 1; i < 8; i++) {
 337                         info->func[i] = PMBUS_HAVE_VOUT
 338                           | PMBUS_HAVE_STATUS_VOUT;
 339                         data->vout_min[i] = 0xffff;
 340                 }
 341                 break;
 342         case ltc3880:
 343                 info->read_word_data = ltc3880_read_word_data;
 344                 info->pages = 2;
 345                 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
 346                   | PMBUS_HAVE_STATUS_INPUT
 347                   | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 348                   | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
 349                   | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
 350                   | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
 351                 info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 352                   | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
 353                   | PMBUS_HAVE_POUT
 354                   | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
 355                 data->vout_min[1] = 0xffff;
 356                 break;
 357         default:
 358                 return -ENODEV;
 359         }
 360
 361         return pmbus_do_probe(client, id, info);
 362 }
 363
 364 /* This is the driver that will be inserted */
 365 static struct i2c_driver ltc2978_driver = {
 366         .driver = {
 367                    .name = "ltc2978",
 368                    },
 369         .probe = ltc2978_probe,
 370         .remove = pmbus_do_remove,
 371         .id_table = ltc2978_id,
 372 };
 373
 374 module_i2c_driver(ltc2978_driver);
 375
 376 MODULE_AUTHOR("Guenter Roeck");
 377 MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
 378 MODULE_LICENSE("GPL");