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Linux/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 = devm_kzalloc(&pdev->dev, sizeof(struct platform_info),
485                              GFP_KERNEL);
486         if (!pinfo)
487                 return -ENOMEM;
488 
489         /* Initializing the hardware */
490         ret = mid_initialize_adc(&pdev->dev);
491         if (ret) {
492                 dev_err(&pdev->dev, "ADC init failed");
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         return ret;
524 }
525 
526 /**
527  * mid_thermal_remove - mfld thermal finalize
528  * @dev: platform device structure
529  *
530  * MLFD thermal remove unregisters all the sensors from the generic
531  * thermal framework. Can sleep.
532  */
533 static int mid_thermal_remove(struct platform_device *pdev)
534 {
535         int i;
536         struct platform_info *pinfo = platform_get_drvdata(pdev);
537 
538         for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
539                 kfree(pinfo->tzd[i]->devdata);
540                 thermal_zone_device_unregister(pinfo->tzd[i]);
541         }
542 
543         /* Stop the ADC */
544         return configure_adc(0);
545 }
546 
547 #define DRIVER_NAME "msic_thermal"
548 
549 static const struct platform_device_id therm_id_table[] = {
550         { DRIVER_NAME, 1 },
551         { "msic_thermal", 1 },
552         { }
553 };
554 
555 static struct platform_driver mid_thermal_driver = {
556         .driver = {
557                 .name = DRIVER_NAME,
558                 .owner = THIS_MODULE,
559                 .pm = &mid_thermal_pm,
560         },
561         .probe = mid_thermal_probe,
562         .remove = mid_thermal_remove,
563         .id_table = therm_id_table,
564 };
565 
566 module_platform_driver(mid_thermal_driver);
567 
568 MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
569 MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
570 MODULE_LICENSE("GPL");
571 

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