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 */
to_msic_die_temp(uint16_t adc_val)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 */
is_valid_adc(uint16_t adc_val,uint16_t min,uint16_t max)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 */
adc_to_temp(int direct,uint16_t adc_val,int * tp)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 */
mid_read_temp(struct thermal_zone_device * tzd,int * temp)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 */
configure_adc(int val)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 */
set_up_therm_channel(u16 base_addr)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 */
reset_stopbit(uint16_t addr)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 */
find_free_channel(void)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 */
mid_initialize_adc(struct device * dev)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 */
initialize_sensor(int index)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 #ifdef CONFIG_PM_SLEEP
419 /**
420 * mid_thermal_resume - resume routine
421 * @dev: device structure
422 *
423 * mid thermal resume: re-initializes the adc. Can sleep.
424 */
mid_thermal_resume(struct device * dev)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 */
mid_thermal_suspend(struct device * dev)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 #endif
447
448 static SIMPLE_DEV_PM_OPS(mid_thermal_pm,
449 mid_thermal_suspend, mid_thermal_resume);
450
451 /**
452 * read_curr_temp - reads the current temperature and stores in temp
453 * @temp: holds the current temperature value after reading
454 *
455 * Can sleep
456 */
read_curr_temp(struct thermal_zone_device * tzd,int * temp)457 static int read_curr_temp(struct thermal_zone_device *tzd, int *temp)
458 {
459 WARN_ON(tzd == NULL);
460 return mid_read_temp(tzd, temp);
461 }
462
463 /* Can't be const */
464 static struct thermal_zone_device_ops tzd_ops = {
465 .get_temp = read_curr_temp,
466 };
467
468 /**
469 * mid_thermal_probe - mfld thermal initialize
470 * @pdev: platform device structure
471 *
472 * mid thermal probe initializes the hardware and registers
473 * all the sensors with the generic thermal framework. Can sleep.
474 */
mid_thermal_probe(struct platform_device * pdev)475 static int mid_thermal_probe(struct platform_device *pdev)
476 {
477 static char *name[MSIC_THERMAL_SENSORS] = {
478 "skin0", "skin1", "sys", "msicdie"
479 };
480
481 int ret;
482 int i;
483 struct platform_info *pinfo;
484
485 pinfo = devm_kzalloc(&pdev->dev, sizeof(struct platform_info),
486 GFP_KERNEL);
487 if (!pinfo)
488 return -ENOMEM;
489
490 /* Initializing the hardware */
491 ret = mid_initialize_adc(&pdev->dev);
492 if (ret) {
493 dev_err(&pdev->dev, "ADC init failed");
494 return ret;
495 }
496
497 /* Register each sensor with the generic thermal framework*/
498 for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
499 struct thermal_device_info *td_info = initialize_sensor(i);
500
501 if (!td_info) {
502 ret = -ENOMEM;
503 goto err;
504 }
505 pinfo->tzd[i] = thermal_zone_device_register(name[i],
506 0, 0, td_info, &tzd_ops, NULL, 0, 0);
507 if (IS_ERR(pinfo->tzd[i])) {
508 kfree(td_info);
509 ret = PTR_ERR(pinfo->tzd[i]);
510 goto err;
511 }
512 }
513
514 pinfo->pdev = pdev;
515 platform_set_drvdata(pdev, pinfo);
516 return 0;
517
518 err:
519 while (--i >= 0) {
520 kfree(pinfo->tzd[i]->devdata);
521 thermal_zone_device_unregister(pinfo->tzd[i]);
522 }
523 configure_adc(0);
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 */
mid_thermal_remove(struct platform_device * pdev)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 /* Stop the ADC */
545 return configure_adc(0);
546 }
547
548 #define DRIVER_NAME "msic_thermal"
549
550 static const struct platform_device_id therm_id_table[] = {
551 { DRIVER_NAME, 1 },
552 { }
553 };
554 MODULE_DEVICE_TABLE(platform, therm_id_table);
555
556 static struct platform_driver mid_thermal_driver = {
557 .driver = {
558 .name = DRIVER_NAME,
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