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, unsigned long *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, unsigned long *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         unsigned long curr_temp;
 184
 185
 186         addr = td_info->chnl_addr;
 187
 188         /* Enable the msic for conversion before reading */
 189         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCRRDATA_ENBL);
 190         if (ret)
 191                 return ret;
 192
 193         /* Re-toggle the RRDATARD bit (temporary workaround) */
 194         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCTHERM_ENBL);
 195         if (ret)
 196                 return ret;
 197
 198         /* Read the higher bits of data */
 199         ret = intel_msic_reg_read(addr, &data);
 200         if (ret)
 201                 return ret;
 202
 203         /* Shift bits to accommodate the lower two data bits */
 204         adc_val = (data << 2);
 205         addr++;
 206
 207         ret = intel_msic_reg_read(addr, &data);/* Read lower bits */
 208         if (ret)
 209                 return ret;
 210
 211         /* Adding lower two bits to the higher bits */
 212         data &= 03;
 213         adc_val += data;
 214
 215         /* Convert ADC value to temperature */
 216         ret = adc_to_temp(td_info->direct, adc_val, &curr_temp);
 217         if (ret == 0)
 218                 *temp = td_info->curr_temp = curr_temp;
 219         return ret;
 220 }
 221
 222 /**
 223  * configure_adc - enables/disables the ADC for conversion
 224  * @val: zero: disables the ADC non-zero:enables the ADC
 225  *
 226  * Enable/Disable the ADC depending on the argument
 227  *
 228  * Can sleep
 229  */
 230 static int configure_adc(int val)
 231 {
 232         int ret;
 233         uint8_t data;
 234
 235         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
 236         if (ret)
 237                 return ret;
 238
 239         if (val) {
 240                 /* Enable and start the ADC */
 241                 data |= (MSIC_ADC_ENBL | MSIC_ADC_START);
 242         } else {
 243                 /* Just stop the ADC */
 244                 data &= (~MSIC_ADC_START);
 245         }
 246         return intel_msic_reg_write(INTEL_MSIC_ADC1CNTL1, data);
 247 }
 248
 249 /**
 250  * set_up_therm_channel - enable thermal channel for conversion
 251  * @base_addr: index of free msic ADC channel
 252  *
 253  * Enable all the three channels for conversion
 254  *
 255  * Can sleep
 256  */
 257 static int set_up_therm_channel(u16 base_addr)
 258 {
 259         int ret;
 260
 261         /* Enable all the sensor channels */
 262         ret = intel_msic_reg_write(base_addr, SKIN_SENSOR0_CODE);
 263         if (ret)
 264                 return ret;
 265
 266         ret = intel_msic_reg_write(base_addr + 1, SKIN_SENSOR1_CODE);
 267         if (ret)
 268                 return ret;
 269
 270         ret = intel_msic_reg_write(base_addr + 2, SYS_SENSOR_CODE);
 271         if (ret)
 272                 return ret;
 273
 274         /* Since this is the last channel, set the stop bit
 275          * to 1 by ORing the DIE_SENSOR_CODE with 0x10 */
 276         ret = intel_msic_reg_write(base_addr + 3,
 277                         (MSIC_DIE_SENSOR_CODE | 0x10));
 278         if (ret)
 279                 return ret;
 280
 281         /* Enable ADC and start it */
 282         return configure_adc(1);
 283 }
 284
 285 /**
 286  * reset_stopbit - sets the stop bit to 0 on the given channel
 287  * @addr: address of the channel
 288  *
 289  * Can sleep
 290  */
 291 static int reset_stopbit(uint16_t addr)
 292 {
 293         int ret;
 294         uint8_t data;
 295         ret = intel_msic_reg_read(addr, &data);
 296         if (ret)
 297                 return ret;
 298         /* Set the stop bit to zero */
 299         return intel_msic_reg_write(addr, (data & 0xEF));
 300 }
 301
 302 /**
 303  * find_free_channel - finds an empty channel for conversion
 304  *
 305  * If the ADC is not enabled then start using 0th channel
 306  * itself. Otherwise find an empty channel by looking for a
 307  * channel in which the stopbit is set to 1. returns the index
 308  * of the first free channel if succeeds or an error code.
 309  *
 310  * Context: can sleep
 311  *
 312  * FIXME: Ultimately the channel allocator will move into the intel_scu_ipc
 313  * code.
 314  */
 315 static int find_free_channel(void)
 316 {
 317         int ret;
 318         int i;
 319         uint8_t data;
 320
 321         /* check whether ADC is enabled */
 322         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
 323         if (ret)
 324                 return ret;
 325
 326         if ((data & MSIC_ADC_ENBL) == 0)
 327                 return 0;
 328
 329         /* ADC is already enabled; Looking for an empty channel */
 330         for (i = 0; i < ADC_CHANLS_MAX; i++) {
 331                 ret = intel_msic_reg_read(ADC_CHNL_START_ADDR + i, &data);
 332                 if (ret)
 333                         return ret;
 334
 335                 if (data & MSIC_STOPBIT_MASK) {
 336                         ret = i;
 337                         break;
 338                 }
 339         }
 340         return (ret > ADC_LOOP_MAX) ? (-EINVAL) : ret;
 341 }
 342
 343 /**
 344  * mid_initialize_adc - initializing the ADC
 345  * @dev: our device structure
 346  *
 347  * Initialize the ADC for reading thermistor values. Can sleep.
 348  */
 349 static int mid_initialize_adc(struct device *dev)
 350 {
 351         u8  data;
 352         u16 base_addr;
 353         int ret;
 354
 355         /*
 356          * Ensure that adctherm is disabled before we
 357          * initialize the ADC
 358          */
 359         ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL3, &data);
 360         if (ret)
 361                 return ret;
 362
 363         data &= ~MSIC_ADCTHERM_MASK;
 364         ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, data);
 365         if (ret)
 366                 return ret;
 367
 368         /* Index of the first channel in which the stop bit is set */
 369         channel_index = find_free_channel();
 370         if (channel_index < 0) {
 371                 dev_err(dev, "No free ADC channels");
 372                 return channel_index;
 373         }
 374
 375         base_addr = ADC_CHNL_START_ADDR + channel_index;
 376
 377         if (!(channel_index == 0 || channel_index == ADC_LOOP_MAX)) {
 378                 /* Reset stop bit for channels other than 0 and 12 */
 379                 ret = reset_stopbit(base_addr);
 380                 if (ret)
 381                         return ret;
 382
 383                 /* Index of the first free channel */
 384                 base_addr++;
 385                 channel_index++;
 386         }
 387
 388         ret = set_up_therm_channel(base_addr);
 389         if (ret) {
 390                 dev_err(dev, "unable to enable ADC");
 391                 return ret;
 392         }
 393         dev_dbg(dev, "ADC initialization successful");
 394         return ret;
 395 }
 396
 397 /**
 398  * initialize_sensor - sets default temp and timer ranges
 399  * @index: index of the sensor
 400  *
 401  * Context: can sleep
 402  */
 403 static struct thermal_device_info *initialize_sensor(int index)
 404 {
 405         struct thermal_device_info *td_info =
 406                 kzalloc(sizeof(struct thermal_device_info), GFP_KERNEL);
 407
 408         if (!td_info)
 409                 return NULL;
 410
 411         /* Set the base addr of the channel for this sensor */
 412         td_info->chnl_addr = ADC_DATA_START_ADDR + 2 * (channel_index + index);
 413         /* Sensor 3 is direct conversion */
 414         if (index == 3)
 415                 td_info->direct = 1;
 416         return td_info;
 417 }
 418
 419 /**
 420  * mid_thermal_resume - resume routine
 421  * @dev: device structure
 422  *
 423  * mid thermal resume: re-initializes the adc. Can sleep.
 424  */
 425 static int mid_thermal_resume(struct device *dev)
 426 {
 427         return mid_initialize_adc(dev);
 428 }
 429
 430 /**
 431  * mid_thermal_suspend - suspend routine
 432  * @dev: device structure
 433  *
 434  * mid thermal suspend implements the suspend functionality
 435  * by stopping the ADC. Can sleep.
 436  */
 437 static int mid_thermal_suspend(struct device *dev)
 438 {
 439         /*
 440          * This just stops the ADC and does not disable it.
 441          * temporary workaround until we have a generic ADC driver.
 442          * If 0 is passed, it disables the ADC.
 443          */
 444         return configure_adc(0);
 445 }
 446
 447 static SIMPLE_DEV_PM_OPS(mid_thermal_pm,
 448                          mid_thermal_suspend, mid_thermal_resume);
 449
 450 /**
 451  * read_curr_temp - reads the current temperature and stores in temp
 452  * @temp: holds the current temperature value after reading
 453  *
 454  * Can sleep
 455  */
 456 static int read_curr_temp(struct thermal_zone_device *tzd, unsigned long *temp)
 457 {
 458         WARN_ON(tzd == NULL);
 459         return mid_read_temp(tzd, temp);
 460 }
 461
 462 /* Can't be const */
 463 static struct thermal_zone_device_ops tzd_ops = {
 464         .get_temp = read_curr_temp,
 465 };
 466
 467 /**
 468  * mid_thermal_probe - mfld thermal initialize
 469  * @pdev: platform device structure
 470  *
 471  * mid thermal probe initializes the hardware and registers
 472  * all the sensors with the generic thermal framework. Can sleep.
 473  */
 474 static int mid_thermal_probe(struct platform_device *pdev)
 475 {
 476         static char *name[MSIC_THERMAL_SENSORS] = {
 477                 "skin0", "skin1", "sys", "msicdie"
 478         };
 479
 480         int ret;
 481         int i;
 482         struct platform_info *pinfo;
 483
 484         pinfo = kzalloc(sizeof(struct platform_info), 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                 kfree(pinfo);
 493                 return ret;
 494         }
 495
 496         /* Register each sensor with the generic thermal framework*/
 497         for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
 498                 struct thermal_device_info *td_info = initialize_sensor(i);
 499
 500                 if (!td_info) {
 501                         ret = -ENOMEM;
 502                         goto err;
 503                 }
 504                 pinfo->tzd[i] = thermal_zone_device_register(name[i],
 505                                 0, 0, td_info, &tzd_ops, NULL, 0, 0);
 506                 if (IS_ERR(pinfo->tzd[i])) {
 507                         kfree(td_info);
 508                         ret = PTR_ERR(pinfo->tzd[i]);
 509                         goto err;
 510                 }
 511         }
 512
 513         pinfo->pdev = pdev;
 514         platform_set_drvdata(pdev, pinfo);
 515         return 0;
 516
 517 err:
 518         while (--i >= 0) {
 519                 kfree(pinfo->tzd[i]->devdata);
 520                 thermal_zone_device_unregister(pinfo->tzd[i]);
 521         }
 522         configure_adc(0);
 523         kfree(pinfo);
 524         return ret;
 525 }
 526
 527 /**
 528  * mid_thermal_remove - mfld thermal finalize
 529  * @dev: platform device structure
 530  *
 531  * MLFD thermal remove unregisters all the sensors from the generic
 532  * thermal framework. Can sleep.
 533  */
 534 static int mid_thermal_remove(struct platform_device *pdev)
 535 {
 536         int i;
 537         struct platform_info *pinfo = platform_get_drvdata(pdev);
 538
 539         for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
 540                 kfree(pinfo->tzd[i]->devdata);
 541                 thermal_zone_device_unregister(pinfo->tzd[i]);
 542         }
 543
 544         kfree(pinfo);
 545
 546         /* Stop the ADC */
 547         return configure_adc(0);
 548 }
 549
 550 #define DRIVER_NAME "msic_thermal"
 551
 552 static const struct platform_device_id therm_id_table[] = {
 553         { DRIVER_NAME, 1 },
 554         { "msic_thermal", 1 },
 555         { }
 556 };
 557
 558 static struct platform_driver mid_thermal_driver = {
 559         .driver = {
 560                 .name = DRIVER_NAME,
 561                 .owner = THIS_MODULE,
 562                 .pm = &mid_thermal_pm,
 563         },
 564         .probe = mid_thermal_probe,
 565         .remove = mid_thermal_remove,
 566         .id_table = therm_id_table,
 567 };
 568
 569 module_platform_driver(mid_thermal_driver);
 570
 571 MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
 572 MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
 573 MODULE_LICENSE("GPL");