drivers/platform/x86/intel_mid_thermal.c

   1 /*
   2  * intel_mid_thermal.c - Intel MID platform thermal driver
   3  *
   4  * Copyright (C) 2011 Intel Corporation
   5  *
   6  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; version 2 of the License.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.        See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  20  *
  21  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  22  * Author: Durgadoss R <durgadoss.r@intel.com>
  23  */
  24
  25 #define pr_fmt(fmt) "intel_mid_thermal: " fmt
  26
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/err.h>
  30 #include <linux/param.h>
  31 #include <linux/device.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/slab.h>
  34 #include <linux/pm.h>
  35 #include <linux/thermal.h>
  36 #include <linux/mfd/intel_msic.h>
  37
  38 /* Number of thermal sensors */
  39 #define MSIC_THERMAL_SENSORS    4
  40
  41 /* ADC1 - thermal registers */
  42 #define MSIC_ADC_ENBL           0x10
  43 #define MSIC_ADC_START          0x08
  44
  45 #define MSIC_ADCTHERM_ENBL      0x04
  46 #define MSIC_ADCRRDATA_ENBL     0x05
  47 #define MSIC_CHANL_MASK_VAL     0x0F
  48
  49 #define MSIC_STOPBIT_MASK       16
  50 #define MSIC_ADCTHERM_MASK      4
  51 /* Number of ADC channels */
  52 #define ADC_CHANLS_MAX          15
  53 #define ADC_LOOP_MAX            (ADC_CHANLS_MAX - MSIC_THERMAL_SENSORS)
  54
  55 /* ADC channel code values */
  56 #define SKIN_SENSOR0_CODE       0x08
  57 #define SKIN_SENSOR1_CODE       0x09
  58 #define SYS_SENSOR_CODE         0x0A
  59 #define MSIC_DIE_SENSOR_CODE    0x03
  60
  61 #define SKIN_THERM_SENSOR0      0
  62 #define SKIN_THERM_SENSOR1      1
  63 #define SYS_THERM_SENSOR2       2
  64 #define MSIC_DIE_THERM_SENSOR3  3
  65
  66 /* ADC code range */
  67 #define ADC_MAX                 977
  68 #define ADC_MIN                 162
  69 #define ADC_VAL0C               887
  70 #define ADC_VAL20C              720
  71 #define ADC_VAL40C              508
  72 #define ADC_VAL60C              315
  73
  74 /* ADC base addresses */
  75 #define ADC_CHNL_START_ADDR     INTEL_MSIC_ADC1ADDR0    /* increments by 1 */
  76 #define ADC_DATA_START_ADDR     INTEL_MSIC_ADC1SNS0H    /* increments by 2 */
  77
  78 /* MSIC die attributes */
  79 #define MSIC_DIE_ADC_MIN        488
  80 #define MSIC_DIE_ADC_MAX        1004
  81
  82 /* This holds the address of the first free ADC channel,
  83  * among the 15 channels
  84  */
  85 static int channel_index;
  86
  87 struct platform_info {
  88         struct platform_device *pdev;
  89         struct thermal_zone_device *tzd[MSIC_THERMAL_SENSORS];
  90 };
  91
  92 struct thermal_device_info {
  93         unsigned int chnl_addr;
  94         int direct;
  95         /* This holds the current temperature in millidegree celsius */
  96         long curr_temp;
  97 };
  98
  99 /**
 100  * to_msic_die_temp - converts adc_val to msic_die temperature
 101  * @adc_val: ADC value to be converted
 102  *
 103  * Can sleep
 104  */
 105 static int to_msic_die_temp(uint16_t adc_val)
 106 {
 107         return (368 * (adc_val) / 1000) - 220;
 108 }
 109
 110 /**
 111  * is_valid_adc - checks whether the adc code is within the defined range
 112  * @min: minimum value for the sensor
 113  * @max: maximum value for the sensor
 114  *
 115  * Can sleep
 116  */
 117 static int is_valid_adc(uint16_t adc_val, uint16_t min, uint16_t max)
 118 {
 119         return (adc_val >= min) && (adc_val <= max);
 120 }
 121
 122 /**
 123  * adc_to_temp - converts the ADC code to temperature in C
 124  * @direct: true if ths channel is direct index
 125  * @adc_val: the adc_val that needs to be converted
 126  * @tp: temperature return value
 127  *
 128  * Linear approximation is used to covert the skin adc value into temperature.
 129  * This technique is used to avoid very long look-up table to get
 130  * the appropriate temp value from ADC value.
 131  * The adc code vs sensor temp curve is split into five parts
 132  * to achieve very close approximate temp value with less than
 133  * 0.5C error
 134  */
 135 static int adc_to_temp(int direct, uint16_t adc_val, int *tp)
 136 {
 137         int temp;
 138
 139         /* Direct conversion for die temperature */
 140         if (direct) {
 141                 if (is_valid_adc(adc_val, MSIC_DIE_ADC_MIN, MSIC_DIE_ADC_MAX)) {
 142                         *tp = to_msic_die_temp(adc_val) * 1000;
 143                         return 0;
 144                 }
 145                 return -ERANGE;
 146         }
 147
 148         if (!is_valid_adc(adc_val, ADC_MIN, ADC_MAX))
 149                 return -ERANGE;
 150
 151         /* Linear approximation for skin temperature */
 152         if (adc_val > ADC_VAL0C)
 153                 temp = 177 - (adc_val/5);
 154         else if ((adc_val <= ADC_VAL0C) && (adc_val > ADC_VAL20C))
 155                 temp = 111 - (adc_val/8);
 156         else if ((adc_val <= ADC_VAL20C) && (adc_val > ADC_VAL40C))
 157                 temp = 92 - (adc_val/10);
 158         else if ((adc_val <= ADC_VAL40C) && (adc_val > ADC_VAL60C))
 159                 temp = 91 - (adc_val/10);
 160         else
 161                 temp = 112 - (adc_val/6);
 162
 163         /* Convert temperature in celsius to milli degree celsius */
 164         *tp = temp * 1000;
 165         return 0;
 166 }
 167
 168 /**
 169  * mid_read_temp - read sensors for temperature
 170  * @temp: holds the current temperature for the sensor after reading
 171  *
 172  * reads the adc_code from the channel and converts it to real
 173  * temperature. The converted value is stored in temp.
 174  *
 175  * Can sleep
 176  */
 177 static int mid_read_temp(struct thermal_zone_device *tzd, int *temp)
 178 {
 179         struct thermal_device_info *td_info = tzd->devdata;
 180         uint16_t adc_val, addr;
 181         uint8_t data = 0;
 182         int ret;
 183         int curr_temp;
 184
 185         addr = td_info->chnl_addr;
 186
 187         /* Enable the msic for conversion before reading */
 188         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCRRDATA_ENBL);
 189         if (ret)
 190                 return ret;
 191
 192         /* Re-toggle the RRDATARD bit (temporary workaround) */
 193         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCTHERM_ENBL);
 194         if (ret)
 195                 return ret;
 196
 197         /* Read the higher bits of data */
 198         ret = intel_msic_reg_read(addr, &data);
 199         if (ret)
 200                 return ret;
 201
 202         /* Shift bits to accommodate the lower two data bits */
 203         adc_val = (data << 2);
 204         addr++;
 205
 206         ret = intel_msic_reg_read(addr, &data);/* Read lower bits */
 207         if (ret)
 208                 return ret;
 209
 210         /* Adding lower two bits to the higher bits */
 211         data &= 03;
 212         adc_val += data;
 213
 214         /* Convert ADC value to temperature */
 215         ret = adc_to_temp(td_info->direct, adc_val, &curr_temp);
 216         if (ret == 0)
 217                 *temp = td_info->curr_temp = curr_temp;
 218         return ret;
 219 }
 220
 221 /**
 222  * configure_adc - enables/disables the ADC for conversion
 223  * @val: zero: disables the ADC non-zero:enables the ADC
 224  *
 225  * Enable/Disable the ADC depending on the argument
 226  *
 227  * Can sleep
 228  */
 229 static int configure_adc(int val)
 230 {
 231         int ret;
 232         uint8_t data;
 233
 234         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
 235         if (ret)
 236                 return ret;
 237
 238         if (val) {
 239                 /* Enable and start the ADC */
 240                 data |= (MSIC_ADC_ENBL | MSIC_ADC_START);
 241         } else {
 242                 /* Just stop the ADC */
 243                 data &= (~MSIC_ADC_START);
 244         }
 245         return intel_msic_reg_write(INTEL_MSIC_ADC1CNTL1, data);
 246 }
 247
 248 /**
 249  * set_up_therm_channel - enable thermal channel for conversion
 250  * @base_addr: index of free msic ADC channel
 251  *
 252  * Enable all the three channels for conversion
 253  *
 254  * Can sleep
 255  */
 256 static int set_up_therm_channel(u16 base_addr)
 257 {
 258         int ret;
 259
 260         /* Enable all the sensor channels */
 261         ret = intel_msic_reg_write(base_addr, SKIN_SENSOR0_CODE);
 262         if (ret)
 263                 return ret;
 264
 265         ret = intel_msic_reg_write(base_addr + 1, SKIN_SENSOR1_CODE);
 266         if (ret)
 267                 return ret;
 268
 269         ret = intel_msic_reg_write(base_addr + 2, SYS_SENSOR_CODE);
 270         if (ret)
 271                 return ret;
 272
 273         /* Since this is the last channel, set the stop bit
 274          * to 1 by ORing the DIE_SENSOR_CODE with 0x10 */
 275         ret = intel_msic_reg_write(base_addr + 3,
 276                         (MSIC_DIE_SENSOR_CODE | 0x10));
 277         if (ret)
 278                 return ret;
 279
 280         /* Enable ADC and start it */
 281         return configure_adc(1);
 282 }
 283
 284 /**
 285  * reset_stopbit - sets the stop bit to 0 on the given channel
 286  * @addr: address of the channel
 287  *
 288  * Can sleep
 289  */
 290 static int reset_stopbit(uint16_t addr)
 291 {
 292         int ret;
 293         uint8_t data;
 294         ret = intel_msic_reg_read(addr, &data);
 295         if (ret)
 296                 return ret;
 297         /* Set the stop bit to zero */
 298         return intel_msic_reg_write(addr, (data & 0xEF));
 299 }
 300
 301 /**
 302  * find_free_channel - finds an empty channel for conversion
 303  *
 304  * If the ADC is not enabled then start using 0th channel
 305  * itself. Otherwise find an empty channel by looking for a
 306  * channel in which the stopbit is set to 1. returns the index
 307  * of the first free channel if succeeds or an error code.
 308  *
 309  * Context: can sleep
 310  *
 311  * FIXME: Ultimately the channel allocator will move into the intel_scu_ipc
 312  * code.
 313  */
 314 static int find_free_channel(void)
 315 {
 316         int ret;
 317         int i;
 318         uint8_t data;
 319
 320         /* check whether ADC is enabled */
 321         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
 322         if (ret)
 323                 return ret;
 324
 325         if ((data & MSIC_ADC_ENBL) == 0)
 326                 return 0;
 327
 328         /* ADC is already enabled; Looking for an empty channel */
 329         for (i = 0; i < ADC_CHANLS_MAX; i++) {
 330                 ret = intel_msic_reg_read(ADC_CHNL_START_ADDR + i, &data);
 331                 if (ret)
 332                         return ret;
 333
 334                 if (data & MSIC_STOPBIT_MASK) {
 335                         ret = i;
 336                         break;
 337                 }
 338         }
 339         return (ret > ADC_LOOP_MAX) ? (-EINVAL) : ret;
 340 }
 341
 342 /**
 343  * mid_initialize_adc - initializing the ADC
 344  * @dev: our device structure
 345  *
 346  * Initialize the ADC for reading thermistor values. Can sleep.
 347  */
 348 static int mid_initialize_adc(struct device *dev)
 349 {
 350         u8  data;
 351         u16 base_addr;
 352         int ret;
 353
 354         /*
 355          * Ensure that adctherm is disabled before we
 356          * initialize the ADC
 357          */
 358         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL3, &data);
 359         if (ret)
 360                 return ret;
 361
 362         data &= ~MSIC_ADCTHERM_MASK;
 363         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, data);
 364         if (ret)
 365                 return ret;
 366
 367         /* Index of the first channel in which the stop bit is set */
 368         channel_index = find_free_channel();
 369         if (channel_index < 0) {
 370                 dev_err(dev, "No free ADC channels");
 371                 return channel_index;
 372         }
 373
 374         base_addr = ADC_CHNL_START_ADDR + channel_index;
 375
 376         if (!(channel_index == 0 || channel_index == ADC_LOOP_MAX)) {
 377                 /* Reset stop bit for channels other than 0 and 12 */
 378                 ret = reset_stopbit(base_addr);
 379                 if (ret)
 380                         return ret;
 381
 382                 /* Index of the first free channel */
 383                 base_addr++;
 384                 channel_index++;
 385         }
 386
 387         ret = set_up_therm_channel(base_addr);
 388         if (ret) {
 389                 dev_err(dev, "unable to enable ADC");
 390                 return ret;
 391         }
 392         dev_dbg(dev, "ADC initialization successful");
 393         return ret;
 394 }
 395
 396 /**
 397  * initialize_sensor - sets default temp and timer ranges
 398  * @index: index of the sensor
 399  *
 400  * Context: can sleep
 401  */
 402 static struct thermal_device_info *initialize_sensor(int index)
 403 {
 404         struct thermal_device_info *td_info =
 405                 kzalloc(sizeof(struct thermal_device_info), GFP_KERNEL);
 406
 407         if (!td_info)
 408                 return NULL;
 409
 410         /* Set the base addr of the channel for this sensor */
 411         td_info->chnl_addr = ADC_DATA_START_ADDR + 2 * (channel_index + index);
 412         /* Sensor 3 is direct conversion */
 413         if (index == 3)
 414                 td_info->direct = 1;
 415         return td_info;
 416 }
 417
 418 /**
 419  * mid_thermal_resume - resume routine
 420  * @dev: device structure
 421  *
 422  * mid thermal resume: re-initializes the adc. Can sleep.
 423  */
 424 static int mid_thermal_resume(struct device *dev)
 425 {
 426         return mid_initialize_adc(dev);
 427 }
 428
 429 /**
 430  * mid_thermal_suspend - suspend routine
 431  * @dev: device structure
 432  *
 433  * mid thermal suspend implements the suspend functionality
 434  * by stopping the ADC. Can sleep.
 435  */
 436 static int mid_thermal_suspend(struct device *dev)
 437 {
 438         /*
 439          * This just stops the ADC and does not disable it.
 440          * temporary workaround until we have a generic ADC driver.
 441          * If 0 is passed, it disables the ADC.
 442          */
 443         return configure_adc(0);
 444 }
 445
 446 static SIMPLE_DEV_PM_OPS(mid_thermal_pm,
 447                          mid_thermal_suspend, mid_thermal_resume);
 448
 449 /**
 450  * read_curr_temp - reads the current temperature and stores in temp
 451  * @temp: holds the current temperature value after reading
 452  *
 453  * Can sleep
 454  */
 455 static int read_curr_temp(struct thermal_zone_device *tzd, int *temp)
 456 {
 457         WARN_ON(tzd == NULL);
 458         return mid_read_temp(tzd, temp);
 459 }
 460
 461 /* Can't be const */
 462 static struct thermal_zone_device_ops tzd_ops = {
 463         .get_temp = read_curr_temp,
 464 };
 465
 466 /**
 467  * mid_thermal_probe - mfld thermal initialize
 468  * @pdev: platform device structure
 469  *
 470  * mid thermal probe initializes the hardware and registers
 471  * all the sensors with the generic thermal framework. Can sleep.
 472  */
 473 static int mid_thermal_probe(struct platform_device *pdev)
 474 {
 475         static char *name[MSIC_THERMAL_SENSORS] = {
 476                 "skin0", "skin1", "sys", "msicdie"
 477         };
 478
 479         int ret;
 480         int i;
 481         struct platform_info *pinfo;
 482
 483         pinfo = devm_kzalloc(&pdev->dev, sizeof(struct platform_info),
 484                              GFP_KERNEL);
 485         if (!pinfo)
 486                 return -ENOMEM;
 487
 488         /* Initializing the hardware */
 489         ret = mid_initialize_adc(&pdev->dev);
 490         if (ret) {
 491                 dev_err(&pdev->dev, "ADC init failed");
 492                 return ret;
 493         }
 494
 495         /* Register each sensor with the generic thermal framework*/
 496         for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
 497                 struct thermal_device_info *td_info = initialize_sensor(i);
 498
 499                 if (!td_info) {
 500                         ret = -ENOMEM;
 501                         goto err;
 502                 }
 503                 pinfo->tzd[i] = thermal_zone_device_register(name[i],
 504                                 0, 0, td_info, &tzd_ops, NULL, 0, 0);
 505                 if (IS_ERR(pinfo->tzd[i])) {
 506                         kfree(td_info);
 507                         ret = PTR_ERR(pinfo->tzd[i]);
 508                         goto err;
 509                 }
 510         }
 511
 512         pinfo->pdev = pdev;
 513         platform_set_drvdata(pdev, pinfo);
 514         return 0;
 515
 516 err:
 517         while (--i >= 0) {
 518                 kfree(pinfo->tzd[i]->devdata);
 519                 thermal_zone_device_unregister(pinfo->tzd[i]);
 520         }
 521         configure_adc(0);
 522         return ret;
 523 }
 524
 525 /**
 526  * mid_thermal_remove - mfld thermal finalize
 527  * @dev: platform device structure
 528  *
 529  * MLFD thermal remove unregisters all the sensors from the generic
 530  * thermal framework. Can sleep.
 531  */
 532 static int mid_thermal_remove(struct platform_device *pdev)
 533 {
 534         int i;
 535         struct platform_info *pinfo = platform_get_drvdata(pdev);
 536
 537         for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
 538                 kfree(pinfo->tzd[i]->devdata);
 539                 thermal_zone_device_unregister(pinfo->tzd[i]);
 540         }
 541
 542         /* Stop the ADC */
 543         return configure_adc(0);
 544 }
 545
 546 #define DRIVER_NAME "msic_thermal"
 547
 548 static const struct platform_device_id therm_id_table[] = {
 549         { DRIVER_NAME, 1 },
 550         { "msic_thermal", 1 },
 551         { }
 552 };
 553
 554 static struct platform_driver mid_thermal_driver = {
 555         .driver = {
 556                 .name = DRIVER_NAME,
 557                 .pm = &mid_thermal_pm,
 558         },
 559         .probe = mid_thermal_probe,
 560         .remove = mid_thermal_remove,
 561         .id_table = therm_id_table,
 562 };
 563
 564 module_platform_driver(mid_thermal_driver);
 565
 566 MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
 567 MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
 568 MODULE_LICENSE("GPL");