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 */
85static int channel_index;
86
87struct platform_info {
88	struct platform_device *pdev;
89	struct thermal_zone_device *tzd[MSIC_THERMAL_SENSORS];
90};
91
92struct 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 */
105static 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 */
117static 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 */
135static 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 */
177static 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 */
229static 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 */
256static 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 */
290static 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 */
314static 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 */
348static 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 */
402static 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 */
424static 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 */
436static 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
446static 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 */
455static 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 */
462static 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 */
473static 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
516err:
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 */
532static 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
548static const struct platform_device_id therm_id_table[] = {
549	{ DRIVER_NAME, 1 },
550	{ "msic_thermal", 1 },
551	{ }
552};
553
554static 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
564module_platform_driver(mid_thermal_driver);
565
566MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
567MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
568MODULE_LICENSE("GPL");
569