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
37 #include <asm/intel_scu_ipc.h>
38
39 /* Number of thermal sensors */
40 #define MSIC_THERMAL_SENSORS 4
41
42 /* ADC1 - thermal registers */
43 #define MSIC_THERM_ADC1CNTL1 0x1C0
44 #define MSIC_ADC_ENBL 0x10
45 #define MSIC_ADC_START 0x08
46
47 #define MSIC_THERM_ADC1CNTL3 0x1C2
48 #define MSIC_ADCTHERM_ENBL 0x04
49 #define MSIC_ADCRRDATA_ENBL 0x05
50 #define MSIC_CHANL_MASK_VAL 0x0F
51
52 #define MSIC_STOPBIT_MASK 16
53 #define MSIC_ADCTHERM_MASK 4
54 /* Number of ADC channels */
55 #define ADC_CHANLS_MAX 15
56 #define ADC_LOOP_MAX (ADC_CHANLS_MAX - MSIC_THERMAL_SENSORS)
57
58 /* ADC channel code values */
59 #define SKIN_SENSOR0_CODE 0x08
60 #define SKIN_SENSOR1_CODE 0x09
61 #define SYS_SENSOR_CODE 0x0A
62 #define MSIC_DIE_SENSOR_CODE 0x03
63
64 #define SKIN_THERM_SENSOR0 0
65 #define SKIN_THERM_SENSOR1 1
66 #define SYS_THERM_SENSOR2 2
67 #define MSIC_DIE_THERM_SENSOR3 3
68
69 /* ADC code range */
70 #define ADC_MAX 977
71 #define ADC_MIN 162
72 #define ADC_VAL0C 887
73 #define ADC_VAL20C 720
74 #define ADC_VAL40C 508
75 #define ADC_VAL60C 315
76
77 /* ADC base addresses */
78 #define ADC_CHNL_START_ADDR 0x1C5 /* increments by 1 */
79 #define ADC_DATA_START_ADDR 0x1D4 /* increments by 2 */
80
81 /* MSIC die attributes */
82 #define MSIC_DIE_ADC_MIN 488
83 #define MSIC_DIE_ADC_MAX 1004
84
85 /* This holds the address of the first free ADC channel,
86 * among the 15 channels
87 */
88 static int channel_index;
89
90 struct platform_info {
91 struct platform_device *pdev;
92 struct thermal_zone_device *tzd[MSIC_THERMAL_SENSORS];
93 };
94
95 struct thermal_device_info {
96 unsigned int chnl_addr;
97 int direct;
98 /* This holds the current temperature in millidegree celsius */
99 long curr_temp;
100 };
101
102 /**
103 * to_msic_die_temp - converts adc_val to msic_die temperature
104 * @adc_val: ADC value to be converted
105 *
106 * Can sleep
107 */
to_msic_die_temp(uint16_t adc_val)108 static int to_msic_die_temp(uint16_t adc_val)
109 {
110 return (368 * (adc_val) / 1000) - 220;
111 }
112
113 /**
114 * is_valid_adc - checks whether the adc code is within the defined range
115 * @min: minimum value for the sensor
116 * @max: maximum value for the sensor
117 *
118 * Can sleep
119 */
is_valid_adc(uint16_t adc_val,uint16_t min,uint16_t max)120 static int is_valid_adc(uint16_t adc_val, uint16_t min, uint16_t max)
121 {
122 return (adc_val >= min) && (adc_val <= max);
123 }
124
125 /**
126 * adc_to_temp - converts the ADC code to temperature in C
127 * @direct: true if ths channel is direct index
128 * @adc_val: the adc_val that needs to be converted
129 * @tp: temperature return value
130 *
131 * Linear approximation is used to covert the skin adc value into temperature.
132 * This technique is used to avoid very long look-up table to get
133 * the appropriate temp value from ADC value.
134 * The adc code vs sensor temp curve is split into five parts
135 * to achieve very close approximate temp value with less than
136 * 0.5C error
137 */
adc_to_temp(int direct,uint16_t adc_val,unsigned long * tp)138 static int adc_to_temp(int direct, uint16_t adc_val, unsigned long *tp)
139 {
140 int temp;
141
142 /* Direct conversion for die temperature */
143 if (direct) {
144 if (is_valid_adc(adc_val, MSIC_DIE_ADC_MIN, MSIC_DIE_ADC_MAX)) {
145 *tp = to_msic_die_temp(adc_val) * 1000;
146 return 0;
147 }
148 return -ERANGE;
149 }
150
151 if (!is_valid_adc(adc_val, ADC_MIN, ADC_MAX))
152 return -ERANGE;
153
154 /* Linear approximation for skin temperature */
155 if (adc_val > ADC_VAL0C)
156 temp = 177 - (adc_val/5);
157 else if ((adc_val <= ADC_VAL0C) && (adc_val > ADC_VAL20C))
158 temp = 111 - (adc_val/8);
159 else if ((adc_val <= ADC_VAL20C) && (adc_val > ADC_VAL40C))
160 temp = 92 - (adc_val/10);
161 else if ((adc_val <= ADC_VAL40C) && (adc_val > ADC_VAL60C))
162 temp = 91 - (adc_val/10);
163 else
164 temp = 112 - (adc_val/6);
165
166 /* Convert temperature in celsius to milli degree celsius */
167 *tp = temp * 1000;
168 return 0;
169 }
170
171 /**
172 * mid_read_temp - read sensors for temperature
173 * @temp: holds the current temperature for the sensor after reading
174 *
175 * reads the adc_code from the channel and converts it to real
176 * temperature. The converted value is stored in temp.
177 *
178 * Can sleep
179 */
mid_read_temp(struct thermal_zone_device * tzd,unsigned long * temp)180 static int mid_read_temp(struct thermal_zone_device *tzd, unsigned long *temp)
181 {
182 struct thermal_device_info *td_info = tzd->devdata;
183 uint16_t adc_val, addr;
184 uint8_t data = 0;
185 int ret;
186 unsigned long curr_temp;
187
188
189 addr = td_info->chnl_addr;
190
191 /* Enable the msic for conversion before reading */
192 ret = intel_scu_ipc_iowrite8(MSIC_THERM_ADC1CNTL3, MSIC_ADCRRDATA_ENBL);
193 if (ret)
194 return ret;
195
196 /* Re-toggle the RRDATARD bit (temporary workaround) */
197 ret = intel_scu_ipc_iowrite8(MSIC_THERM_ADC1CNTL3, MSIC_ADCTHERM_ENBL);
198 if (ret)
199 return ret;
200
201 /* Read the higher bits of data */
202 ret = intel_scu_ipc_ioread8(addr, &data);
203 if (ret)
204 return ret;
205
206 /* Shift bits to accommodate the lower two data bits */
207 adc_val = (data << 2);
208 addr++;
209
210 ret = intel_scu_ipc_ioread8(addr, &data);/* Read lower bits */
211 if (ret)
212 return ret;
213
214 /* Adding lower two bits to the higher bits */
215 data &= 03;
216 adc_val += data;
217
218 /* Convert ADC value to temperature */
219 ret = adc_to_temp(td_info->direct, adc_val, &curr_temp);
220 if (ret == 0)
221 *temp = td_info->curr_temp = curr_temp;
222 return ret;
223 }
224
225 /**
226 * configure_adc - enables/disables the ADC for conversion
227 * @val: zero: disables the ADC non-zero:enables the ADC
228 *
229 * Enable/Disable the ADC depending on the argument
230 *
231 * Can sleep
232 */
configure_adc(int val)233 static int configure_adc(int val)
234 {
235 int ret;
236 uint8_t data;
237
238 ret = intel_scu_ipc_ioread8(MSIC_THERM_ADC1CNTL1, &data);
239 if (ret)
240 return ret;
241
242 if (val) {
243 /* Enable and start the ADC */
244 data |= (MSIC_ADC_ENBL | MSIC_ADC_START);
245 } else {
246 /* Just stop the ADC */
247 data &= (~MSIC_ADC_START);
248 }
249 return intel_scu_ipc_iowrite8(MSIC_THERM_ADC1CNTL1, data);
250 }
251
252 /**
253 * set_up_therm_channel - enable thermal channel for conversion
254 * @base_addr: index of free msic ADC channel
255 *
256 * Enable all the three channels for conversion
257 *
258 * Can sleep
259 */
set_up_therm_channel(u16 base_addr)260 static int set_up_therm_channel(u16 base_addr)
261 {
262 int ret;
263
264 /* Enable all the sensor channels */
265 ret = intel_scu_ipc_iowrite8(base_addr, SKIN_SENSOR0_CODE);
266 if (ret)
267 return ret;
268
269 ret = intel_scu_ipc_iowrite8(base_addr + 1, SKIN_SENSOR1_CODE);
270 if (ret)
271 return ret;
272
273 ret = intel_scu_ipc_iowrite8(base_addr + 2, SYS_SENSOR_CODE);
274 if (ret)
275 return ret;
276
277 /* Since this is the last channel, set the stop bit
278 * to 1 by ORing the DIE_SENSOR_CODE with 0x10 */
279 ret = intel_scu_ipc_iowrite8(base_addr + 3,
280 (MSIC_DIE_SENSOR_CODE | 0x10));
281 if (ret)
282 return ret;
283
284 /* Enable ADC and start it */
285 return configure_adc(1);
286 }
287
288 /**
289 * reset_stopbit - sets the stop bit to 0 on the given channel
290 * @addr: address of the channel
291 *
292 * Can sleep
293 */
reset_stopbit(uint16_t addr)294 static int reset_stopbit(uint16_t addr)
295 {
296 int ret;
297 uint8_t data;
298 ret = intel_scu_ipc_ioread8(addr, &data);
299 if (ret)
300 return ret;
301 /* Set the stop bit to zero */
302 return intel_scu_ipc_iowrite8(addr, (data & 0xEF));
303 }
304
305 /**
306 * find_free_channel - finds an empty channel for conversion
307 *
308 * If the ADC is not enabled then start using 0th channel
309 * itself. Otherwise find an empty channel by looking for a
310 * channel in which the stopbit is set to 1. returns the index
311 * of the first free channel if succeeds or an error code.
312 *
313 * Context: can sleep
314 *
315 * FIXME: Ultimately the channel allocator will move into the intel_scu_ipc
316 * code.
317 */
find_free_channel(void)318 static int find_free_channel(void)
319 {
320 int ret;
321 int i;
322 uint8_t data;
323
324 /* check whether ADC is enabled */
325 ret = intel_scu_ipc_ioread8(MSIC_THERM_ADC1CNTL1, &data);
326 if (ret)
327 return ret;
328
329 if ((data & MSIC_ADC_ENBL) == 0)
330 return 0;
331
332 /* ADC is already enabled; Looking for an empty channel */
333 for (i = 0; i < ADC_CHANLS_MAX; i++) {
334 ret = intel_scu_ipc_ioread8(ADC_CHNL_START_ADDR + i, &data);
335 if (ret)
336 return ret;
337
338 if (data & MSIC_STOPBIT_MASK) {
339 ret = i;
340 break;
341 }
342 }
343 return (ret > ADC_LOOP_MAX) ? (-EINVAL) : ret;
344 }
345
346 /**
347 * mid_initialize_adc - initializing the ADC
348 * @dev: our device structure
349 *
350 * Initialize the ADC for reading thermistor values. Can sleep.
351 */
mid_initialize_adc(struct device * dev)352 static int mid_initialize_adc(struct device *dev)
353 {
354 u8 data;
355 u16 base_addr;
356 int ret;
357
358 /*
359 * Ensure that adctherm is disabled before we
360 * initialize the ADC
361 */
362 ret = intel_scu_ipc_ioread8(MSIC_THERM_ADC1CNTL3, &data);
363 if (ret)
364 return ret;
365
366 if (data & MSIC_ADCTHERM_MASK)
367 dev_warn(dev, "ADCTHERM already set");
368
369 /* Index of the first channel in which the stop bit is set */
370 channel_index = find_free_channel();
371 if (channel_index < 0) {
372 dev_err(dev, "No free ADC channels");
373 return channel_index;
374 }
375
376 base_addr = ADC_CHNL_START_ADDR + channel_index;
377
378 if (!(channel_index == 0 || channel_index == ADC_LOOP_MAX)) {
379 /* Reset stop bit for channels other than 0 and 12 */
380 ret = reset_stopbit(base_addr);
381 if (ret)
382 return ret;
383
384 /* Index of the first free channel */
385 base_addr++;
386 channel_index++;
387 }
388
389 ret = set_up_therm_channel(base_addr);
390 if (ret) {
391 dev_err(dev, "unable to enable ADC");
392 return ret;
393 }
394 dev_dbg(dev, "ADC initialization successful");
395 return ret;
396 }
397
398 /**
399 * initialize_sensor - sets default temp and timer ranges
400 * @index: index of the sensor
401 *
402 * Context: can sleep
403 */
initialize_sensor(int index)404 static struct thermal_device_info *initialize_sensor(int index)
405 {
406 struct thermal_device_info *td_info =
407 kzalloc(sizeof(struct thermal_device_info), GFP_KERNEL);
408
409 if (!td_info)
410 return NULL;
411
412 /* Set the base addr of the channel for this sensor */
413 td_info->chnl_addr = ADC_DATA_START_ADDR + 2 * (channel_index + index);
414 /* Sensor 3 is direct conversion */
415 if (index == 3)
416 td_info->direct = 1;
417 return td_info;
418 }
419
420 /**
421 * mid_thermal_resume - resume routine
422 * @pdev: platform device structure
423 *
424 * mid thermal resume: re-initializes the adc. Can sleep.
425 */
mid_thermal_resume(struct platform_device * pdev)426 static int mid_thermal_resume(struct platform_device *pdev)
427 {
428 return mid_initialize_adc(&pdev->dev);
429 }
430
431 /**
432 * mid_thermal_suspend - suspend routine
433 * @pdev: platform device structure
434 *
435 * mid thermal suspend implements the suspend functionality
436 * by stopping the ADC. Can sleep.
437 */
mid_thermal_suspend(struct platform_device * pdev,pm_message_t mesg)438 static int mid_thermal_suspend(struct platform_device *pdev, pm_message_t mesg)
439 {
440 /*
441 * This just stops the ADC and does not disable it.
442 * temporary workaround until we have a generic ADC driver.
443 * If 0 is passed, it disables the ADC.
444 */
445 return configure_adc(0);
446 }
447
448 /**
449 * read_curr_temp - reads the current temperature and stores in temp
450 * @temp: holds the current temperature value after reading
451 *
452 * Can sleep
453 */
read_curr_temp(struct thermal_zone_device * tzd,unsigned long * temp)454 static int read_curr_temp(struct thermal_zone_device *tzd, unsigned long *temp)
455 {
456 WARN_ON(tzd == NULL);
457 return mid_read_temp(tzd, temp);
458 }
459
460 /* Can't be const */
461 static struct thermal_zone_device_ops tzd_ops = {
462 .get_temp = read_curr_temp,
463 };
464
465 /**
466 * mid_thermal_probe - mfld thermal initialize
467 * @pdev: platform device structure
468 *
469 * mid thermal probe initializes the hardware and registers
470 * all the sensors with the generic thermal framework. Can sleep.
471 */
mid_thermal_probe(struct platform_device * pdev)472 static int mid_thermal_probe(struct platform_device *pdev)
473 {
474 static char *name[MSIC_THERMAL_SENSORS] = {
475 "skin0", "skin1", "sys", "msicdie"
476 };
477
478 int ret;
479 int i;
480 struct platform_info *pinfo;
481
482 pinfo = kzalloc(sizeof(struct platform_info), GFP_KERNEL);
483 if (!pinfo)
484 return -ENOMEM;
485
486 /* Initializing the hardware */
487 ret = mid_initialize_adc(&pdev->dev);
488 if (ret) {
489 dev_err(&pdev->dev, "ADC init failed");
490 kfree(pinfo);
491 return ret;
492 }
493
494 /* Register each sensor with the generic thermal framework*/
495 for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
496 struct thermal_device_info *td_info = initialize_sensor(i);
497
498 if (!td_info) {
499 ret = -ENOMEM;
500 goto err;
501 }
502 pinfo->tzd[i] = thermal_zone_device_register(name[i],
503 0, td_info, &tzd_ops, 0, 0, 0, 0);
504 if (IS_ERR(pinfo->tzd[i])) {
505 kfree(td_info);
506 ret = PTR_ERR(pinfo->tzd[i]);
507 goto err;
508 }
509 }
510
511 pinfo->pdev = pdev;
512 platform_set_drvdata(pdev, pinfo);
513 return 0;
514
515 err:
516 while (--i >= 0) {
517 kfree(pinfo->tzd[i]->devdata);
518 thermal_zone_device_unregister(pinfo->tzd[i]);
519 }
520 configure_adc(0);
521 kfree(pinfo);
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 */
mid_thermal_remove(struct platform_device * pdev)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 kfree(pinfo);
543 platform_set_drvdata(pdev, NULL);
544
545 /* Stop the ADC */
546 return configure_adc(0);
547 }
548
549 #define DRIVER_NAME "msic_sensor"
550
551 static const struct platform_device_id therm_id_table[] = {
552 { DRIVER_NAME, 1 },
553 { }
554 };
555
556 static struct platform_driver mid_thermal_driver = {
557 .driver = {
558 .name = DRIVER_NAME,
559 .owner = THIS_MODULE,
560 },
561 .probe = mid_thermal_probe,
562 .suspend = mid_thermal_suspend,
563 .resume = mid_thermal_resume,
564 .remove = __devexit_p(mid_thermal_remove),
565 .id_table = therm_id_table,
566 };
567
mid_thermal_module_init(void)568 static int __init mid_thermal_module_init(void)
569 {
570 return platform_driver_register(&mid_thermal_driver);
571 }
572
mid_thermal_module_exit(void)573 static void __exit mid_thermal_module_exit(void)
574 {
575 platform_driver_unregister(&mid_thermal_driver);
576 }
577
578 module_init(mid_thermal_module_init);
579 module_exit(mid_thermal_module_exit);
580
581 MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
582 MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
583 MODULE_LICENSE("GPL");
584