xref: /openbmc/linux/drivers/input/misc/ad714x.c (revision 9b93eb47)
1 /*
2  * AD714X CapTouch Programmable Controller driver supporting AD7142/3/7/8/7A
3  *
4  * Copyright 2009-2011 Analog Devices Inc.
5  *
6  * Licensed under the GPL-2 or later.
7  */
8 
9 #include <linux/device.h>
10 #include <linux/input.h>
11 #include <linux/interrupt.h>
12 #include <linux/slab.h>
13 #include <linux/input/ad714x.h>
14 #include <linux/module.h>
15 #include "ad714x.h"
16 
17 #define AD714X_PWR_CTRL           0x0
18 #define AD714X_STG_CAL_EN_REG     0x1
19 #define AD714X_AMB_COMP_CTRL0_REG 0x2
20 #define AD714X_PARTID_REG         0x17
21 #define AD7142_PARTID             0xE620
22 #define AD7143_PARTID             0xE630
23 #define AD7147_PARTID             0x1470
24 #define AD7148_PARTID             0x1480
25 #define AD714X_STAGECFG_REG       0x80
26 #define AD714X_SYSCFG_REG         0x0
27 
28 #define STG_LOW_INT_EN_REG     0x5
29 #define STG_HIGH_INT_EN_REG    0x6
30 #define STG_COM_INT_EN_REG     0x7
31 #define STG_LOW_INT_STA_REG    0x8
32 #define STG_HIGH_INT_STA_REG   0x9
33 #define STG_COM_INT_STA_REG    0xA
34 
35 #define CDC_RESULT_S0          0xB
36 #define CDC_RESULT_S1          0xC
37 #define CDC_RESULT_S2          0xD
38 #define CDC_RESULT_S3          0xE
39 #define CDC_RESULT_S4          0xF
40 #define CDC_RESULT_S5          0x10
41 #define CDC_RESULT_S6          0x11
42 #define CDC_RESULT_S7          0x12
43 #define CDC_RESULT_S8          0x13
44 #define CDC_RESULT_S9          0x14
45 #define CDC_RESULT_S10         0x15
46 #define CDC_RESULT_S11         0x16
47 
48 #define STAGE0_AMBIENT		0xF1
49 #define STAGE1_AMBIENT		0x115
50 #define STAGE2_AMBIENT		0x139
51 #define STAGE3_AMBIENT		0x15D
52 #define STAGE4_AMBIENT		0x181
53 #define STAGE5_AMBIENT		0x1A5
54 #define STAGE6_AMBIENT		0x1C9
55 #define STAGE7_AMBIENT		0x1ED
56 #define STAGE8_AMBIENT		0x211
57 #define STAGE9_AMBIENT		0x234
58 #define STAGE10_AMBIENT		0x259
59 #define STAGE11_AMBIENT		0x27D
60 
61 #define PER_STAGE_REG_NUM      36
62 #define STAGE_CFGREG_NUM       8
63 #define SYS_CFGREG_NUM         8
64 
65 /*
66  * driver information which will be used to maintain the software flow
67  */
68 enum ad714x_device_state { IDLE, JITTER, ACTIVE, SPACE };
69 
70 struct ad714x_slider_drv {
71 	int highest_stage;
72 	int abs_pos;
73 	int flt_pos;
74 	enum ad714x_device_state state;
75 	struct input_dev *input;
76 };
77 
78 struct ad714x_wheel_drv {
79 	int abs_pos;
80 	int flt_pos;
81 	int pre_highest_stage;
82 	int highest_stage;
83 	enum ad714x_device_state state;
84 	struct input_dev *input;
85 };
86 
87 struct ad714x_touchpad_drv {
88 	int x_highest_stage;
89 	int x_flt_pos;
90 	int x_abs_pos;
91 	int y_highest_stage;
92 	int y_flt_pos;
93 	int y_abs_pos;
94 	int left_ep;
95 	int left_ep_val;
96 	int right_ep;
97 	int right_ep_val;
98 	int top_ep;
99 	int top_ep_val;
100 	int bottom_ep;
101 	int bottom_ep_val;
102 	enum ad714x_device_state state;
103 	struct input_dev *input;
104 };
105 
106 struct ad714x_button_drv {
107 	enum ad714x_device_state state;
108 	/*
109 	 * Unlike slider/wheel/touchpad, all buttons point to
110 	 * same input_dev instance
111 	 */
112 	struct input_dev *input;
113 };
114 
115 struct ad714x_driver_data {
116 	struct ad714x_slider_drv *slider;
117 	struct ad714x_wheel_drv *wheel;
118 	struct ad714x_touchpad_drv *touchpad;
119 	struct ad714x_button_drv *button;
120 };
121 
122 /*
123  * information to integrate all things which will be private data
124  * of spi/i2c device
125  */
126 
127 static void ad714x_use_com_int(struct ad714x_chip *ad714x,
128 				int start_stage, int end_stage)
129 {
130 	unsigned short data;
131 	unsigned short mask;
132 
133 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
134 
135 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
136 	data |= 1 << end_stage;
137 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
138 
139 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
140 	data &= ~mask;
141 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
142 }
143 
144 static void ad714x_use_thr_int(struct ad714x_chip *ad714x,
145 				int start_stage, int end_stage)
146 {
147 	unsigned short data;
148 	unsigned short mask;
149 
150 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
151 
152 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
153 	data &= ~(1 << end_stage);
154 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
155 
156 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
157 	data |= mask;
158 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
159 }
160 
161 static int ad714x_cal_highest_stage(struct ad714x_chip *ad714x,
162 					int start_stage, int end_stage)
163 {
164 	int max_res = 0;
165 	int max_idx = 0;
166 	int i;
167 
168 	for (i = start_stage; i <= end_stage; i++) {
169 		if (ad714x->sensor_val[i] > max_res) {
170 			max_res = ad714x->sensor_val[i];
171 			max_idx = i;
172 		}
173 	}
174 
175 	return max_idx;
176 }
177 
178 static int ad714x_cal_abs_pos(struct ad714x_chip *ad714x,
179 				int start_stage, int end_stage,
180 				int highest_stage, int max_coord)
181 {
182 	int a_param, b_param;
183 
184 	if (highest_stage == start_stage) {
185 		a_param = ad714x->sensor_val[start_stage + 1];
186 		b_param = ad714x->sensor_val[start_stage] +
187 			ad714x->sensor_val[start_stage + 1];
188 	} else if (highest_stage == end_stage) {
189 		a_param = ad714x->sensor_val[end_stage] *
190 			(end_stage - start_stage) +
191 			ad714x->sensor_val[end_stage - 1] *
192 			(end_stage - start_stage - 1);
193 		b_param = ad714x->sensor_val[end_stage] +
194 			ad714x->sensor_val[end_stage - 1];
195 	} else {
196 		a_param = ad714x->sensor_val[highest_stage] *
197 			(highest_stage - start_stage) +
198 			ad714x->sensor_val[highest_stage - 1] *
199 			(highest_stage - start_stage - 1) +
200 			ad714x->sensor_val[highest_stage + 1] *
201 			(highest_stage - start_stage + 1);
202 		b_param = ad714x->sensor_val[highest_stage] +
203 			ad714x->sensor_val[highest_stage - 1] +
204 			ad714x->sensor_val[highest_stage + 1];
205 	}
206 
207 	return (max_coord / (end_stage - start_stage)) * a_param / b_param;
208 }
209 
210 /*
211  * One button can connect to multi positive and negative of CDCs
212  * Multi-buttons can connect to same positive/negative of one CDC
213  */
214 static void ad714x_button_state_machine(struct ad714x_chip *ad714x, int idx)
215 {
216 	struct ad714x_button_plat *hw = &ad714x->hw->button[idx];
217 	struct ad714x_button_drv *sw = &ad714x->sw->button[idx];
218 
219 	switch (sw->state) {
220 	case IDLE:
221 		if (((ad714x->h_state & hw->h_mask) == hw->h_mask) &&
222 		    ((ad714x->l_state & hw->l_mask) == hw->l_mask)) {
223 			dev_dbg(ad714x->dev, "button %d touched\n", idx);
224 			input_report_key(sw->input, hw->keycode, 1);
225 			input_sync(sw->input);
226 			sw->state = ACTIVE;
227 		}
228 		break;
229 
230 	case ACTIVE:
231 		if (((ad714x->h_state & hw->h_mask) != hw->h_mask) ||
232 		    ((ad714x->l_state & hw->l_mask) != hw->l_mask)) {
233 			dev_dbg(ad714x->dev, "button %d released\n", idx);
234 			input_report_key(sw->input, hw->keycode, 0);
235 			input_sync(sw->input);
236 			sw->state = IDLE;
237 		}
238 		break;
239 
240 	default:
241 		break;
242 	}
243 }
244 
245 /*
246  * The response of a sensor is defined by the absolute number of codes
247  * between the current CDC value and the ambient value.
248  */
249 static void ad714x_slider_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
250 {
251 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
252 	int i;
253 
254 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
255 			&ad714x->adc_reg[hw->start_stage],
256 			hw->end_stage - hw->start_stage + 1);
257 
258 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
259 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
260 				&ad714x->amb_reg[i], 1);
261 
262 		ad714x->sensor_val[i] =
263 			abs(ad714x->adc_reg[i] - ad714x->amb_reg[i]);
264 	}
265 }
266 
267 static void ad714x_slider_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
268 {
269 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
270 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
271 
272 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
273 			hw->end_stage);
274 
275 	dev_dbg(ad714x->dev, "slider %d highest_stage:%d\n", idx,
276 		sw->highest_stage);
277 }
278 
279 /*
280  * The formulae are very straight forward. It uses the sensor with the
281  * highest response and the 2 adjacent ones.
282  * When Sensor 0 has the highest response, only sensor 0 and sensor 1
283  * are used in the calculations. Similarly when the last sensor has the
284  * highest response, only the last sensor and the second last sensors
285  * are used in the calculations.
286  *
287  * For i= idx_of_peak_Sensor-1 to i= idx_of_peak_Sensor+1
288  *         v += Sensor response(i)*i
289  *         w += Sensor response(i)
290  * POS=(Number_of_Positions_Wanted/(Number_of_Sensors_Used-1)) *(v/w)
291  */
292 static void ad714x_slider_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
293 {
294 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
295 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
296 
297 	sw->abs_pos = ad714x_cal_abs_pos(ad714x, hw->start_stage, hw->end_stage,
298 		sw->highest_stage, hw->max_coord);
299 
300 	dev_dbg(ad714x->dev, "slider %d absolute position:%d\n", idx,
301 		sw->abs_pos);
302 }
303 
304 /*
305  * To minimise the Impact of the noise on the algorithm, ADI developed a
306  * routine that filters the CDC results after they have been read by the
307  * host processor.
308  * The filter used is an Infinite Input Response(IIR) filter implemented
309  * in firmware and attenuates the noise on the CDC results after they've
310  * been read by the host processor.
311  * Filtered_CDC_result = (Filtered_CDC_result * (10 - Coefficient) +
312  *				Latest_CDC_result * Coefficient)/10
313  */
314 static void ad714x_slider_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
315 {
316 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
317 
318 	sw->flt_pos = (sw->flt_pos * (10 - 4) +
319 			sw->abs_pos * 4)/10;
320 
321 	dev_dbg(ad714x->dev, "slider %d filter position:%d\n", idx,
322 		sw->flt_pos);
323 }
324 
325 static void ad714x_slider_use_com_int(struct ad714x_chip *ad714x, int idx)
326 {
327 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
328 
329 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
330 }
331 
332 static void ad714x_slider_use_thr_int(struct ad714x_chip *ad714x, int idx)
333 {
334 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
335 
336 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
337 }
338 
339 static void ad714x_slider_state_machine(struct ad714x_chip *ad714x, int idx)
340 {
341 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
342 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
343 	unsigned short h_state, c_state;
344 	unsigned short mask;
345 
346 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
347 
348 	h_state = ad714x->h_state & mask;
349 	c_state = ad714x->c_state & mask;
350 
351 	switch (sw->state) {
352 	case IDLE:
353 		if (h_state) {
354 			sw->state = JITTER;
355 			/* In End of Conversion interrupt mode, the AD714X
356 			 * continuously generates hardware interrupts.
357 			 */
358 			ad714x_slider_use_com_int(ad714x, idx);
359 			dev_dbg(ad714x->dev, "slider %d touched\n", idx);
360 		}
361 		break;
362 
363 	case JITTER:
364 		if (c_state == mask) {
365 			ad714x_slider_cal_sensor_val(ad714x, idx);
366 			ad714x_slider_cal_highest_stage(ad714x, idx);
367 			ad714x_slider_cal_abs_pos(ad714x, idx);
368 			sw->flt_pos = sw->abs_pos;
369 			sw->state = ACTIVE;
370 		}
371 		break;
372 
373 	case ACTIVE:
374 		if (c_state == mask) {
375 			if (h_state) {
376 				ad714x_slider_cal_sensor_val(ad714x, idx);
377 				ad714x_slider_cal_highest_stage(ad714x, idx);
378 				ad714x_slider_cal_abs_pos(ad714x, idx);
379 				ad714x_slider_cal_flt_pos(ad714x, idx);
380 				input_report_abs(sw->input, ABS_X, sw->flt_pos);
381 				input_report_key(sw->input, BTN_TOUCH, 1);
382 			} else {
383 				/* When the user lifts off the sensor, configure
384 				 * the AD714X back to threshold interrupt mode.
385 				 */
386 				ad714x_slider_use_thr_int(ad714x, idx);
387 				sw->state = IDLE;
388 				input_report_key(sw->input, BTN_TOUCH, 0);
389 				dev_dbg(ad714x->dev, "slider %d released\n",
390 					idx);
391 			}
392 			input_sync(sw->input);
393 		}
394 		break;
395 
396 	default:
397 		break;
398 	}
399 }
400 
401 /*
402  * When the scroll wheel is activated, we compute the absolute position based
403  * on the sensor values. To calculate the position, we first determine the
404  * sensor that has the greatest response among the 8 sensors that constitutes
405  * the scrollwheel. Then we determined the 2 sensors on either sides of the
406  * sensor with the highest response and we apply weights to these sensors.
407  */
408 static void ad714x_wheel_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
409 {
410 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
411 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
412 
413 	sw->pre_highest_stage = sw->highest_stage;
414 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
415 			hw->end_stage);
416 
417 	dev_dbg(ad714x->dev, "wheel %d highest_stage:%d\n", idx,
418 		sw->highest_stage);
419 }
420 
421 static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
422 {
423 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
424 	int i;
425 
426 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
427 			&ad714x->adc_reg[hw->start_stage],
428 			hw->end_stage - hw->start_stage + 1);
429 
430 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
431 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
432 				&ad714x->amb_reg[i], 1);
433 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
434 			ad714x->sensor_val[i] =
435 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
436 		else
437 			ad714x->sensor_val[i] = 0;
438 	}
439 }
440 
441 /*
442  * When the scroll wheel is activated, we compute the absolute position based
443  * on the sensor values. To calculate the position, we first determine the
444  * sensor that has the greatest response among the sensors that constitutes
445  * the scrollwheel. Then we determined the sensors on either sides of the
446  * sensor with the highest response and we apply weights to these sensors. The
447  * result of this computation gives us the mean value.
448  */
449 
450 static void ad714x_wheel_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
451 {
452 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
453 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
454 	int stage_num = hw->end_stage - hw->start_stage + 1;
455 	int first_before, highest, first_after;
456 	int a_param, b_param;
457 
458 	first_before = (sw->highest_stage + stage_num - 1) % stage_num;
459 	highest = sw->highest_stage;
460 	first_after = (sw->highest_stage + stage_num + 1) % stage_num;
461 
462 	a_param = ad714x->sensor_val[highest] *
463 		(highest - hw->start_stage) +
464 		ad714x->sensor_val[first_before] *
465 		(highest - hw->start_stage - 1) +
466 		ad714x->sensor_val[first_after] *
467 		(highest - hw->start_stage + 1);
468 	b_param = ad714x->sensor_val[highest] +
469 		ad714x->sensor_val[first_before] +
470 		ad714x->sensor_val[first_after];
471 
472 	sw->abs_pos = ((hw->max_coord / (hw->end_stage - hw->start_stage)) *
473 			a_param) / b_param;
474 
475 	if (sw->abs_pos > hw->max_coord)
476 		sw->abs_pos = hw->max_coord;
477 	else if (sw->abs_pos < 0)
478 		sw->abs_pos = 0;
479 }
480 
481 static void ad714x_wheel_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
482 {
483 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
484 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
485 	if (((sw->pre_highest_stage == hw->end_stage) &&
486 			(sw->highest_stage == hw->start_stage)) ||
487 	    ((sw->pre_highest_stage == hw->start_stage) &&
488 			(sw->highest_stage == hw->end_stage)))
489 		sw->flt_pos = sw->abs_pos;
490 	else
491 		sw->flt_pos = ((sw->flt_pos * 30) + (sw->abs_pos * 71)) / 100;
492 
493 	if (sw->flt_pos > hw->max_coord)
494 		sw->flt_pos = hw->max_coord;
495 }
496 
497 static void ad714x_wheel_use_com_int(struct ad714x_chip *ad714x, int idx)
498 {
499 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
500 
501 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
502 }
503 
504 static void ad714x_wheel_use_thr_int(struct ad714x_chip *ad714x, int idx)
505 {
506 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
507 
508 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
509 }
510 
511 static void ad714x_wheel_state_machine(struct ad714x_chip *ad714x, int idx)
512 {
513 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
514 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
515 	unsigned short h_state, c_state;
516 	unsigned short mask;
517 
518 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
519 
520 	h_state = ad714x->h_state & mask;
521 	c_state = ad714x->c_state & mask;
522 
523 	switch (sw->state) {
524 	case IDLE:
525 		if (h_state) {
526 			sw->state = JITTER;
527 			/* In End of Conversion interrupt mode, the AD714X
528 			 * continuously generates hardware interrupts.
529 			 */
530 			ad714x_wheel_use_com_int(ad714x, idx);
531 			dev_dbg(ad714x->dev, "wheel %d touched\n", idx);
532 		}
533 		break;
534 
535 	case JITTER:
536 		if (c_state == mask)	{
537 			ad714x_wheel_cal_sensor_val(ad714x, idx);
538 			ad714x_wheel_cal_highest_stage(ad714x, idx);
539 			ad714x_wheel_cal_abs_pos(ad714x, idx);
540 			sw->flt_pos = sw->abs_pos;
541 			sw->state = ACTIVE;
542 		}
543 		break;
544 
545 	case ACTIVE:
546 		if (c_state == mask) {
547 			if (h_state) {
548 				ad714x_wheel_cal_sensor_val(ad714x, idx);
549 				ad714x_wheel_cal_highest_stage(ad714x, idx);
550 				ad714x_wheel_cal_abs_pos(ad714x, idx);
551 				ad714x_wheel_cal_flt_pos(ad714x, idx);
552 				input_report_abs(sw->input, ABS_WHEEL,
553 					sw->flt_pos);
554 				input_report_key(sw->input, BTN_TOUCH, 1);
555 			} else {
556 				/* When the user lifts off the sensor, configure
557 				 * the AD714X back to threshold interrupt mode.
558 				 */
559 				ad714x_wheel_use_thr_int(ad714x, idx);
560 				sw->state = IDLE;
561 				input_report_key(sw->input, BTN_TOUCH, 0);
562 
563 				dev_dbg(ad714x->dev, "wheel %d released\n",
564 					idx);
565 			}
566 			input_sync(sw->input);
567 		}
568 		break;
569 
570 	default:
571 		break;
572 	}
573 }
574 
575 static void touchpad_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
576 {
577 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
578 	int i;
579 
580 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->x_start_stage,
581 			&ad714x->adc_reg[hw->x_start_stage],
582 			hw->x_end_stage - hw->x_start_stage + 1);
583 
584 	for (i = hw->x_start_stage; i <= hw->x_end_stage; i++) {
585 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
586 				&ad714x->amb_reg[i], 1);
587 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
588 			ad714x->sensor_val[i] =
589 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
590 		else
591 			ad714x->sensor_val[i] = 0;
592 	}
593 }
594 
595 static void touchpad_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
596 {
597 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
598 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
599 
600 	sw->x_highest_stage = ad714x_cal_highest_stage(ad714x,
601 		hw->x_start_stage, hw->x_end_stage);
602 	sw->y_highest_stage = ad714x_cal_highest_stage(ad714x,
603 		hw->y_start_stage, hw->y_end_stage);
604 
605 	dev_dbg(ad714x->dev,
606 		"touchpad %d x_highest_stage:%d, y_highest_stage:%d\n",
607 		idx, sw->x_highest_stage, sw->y_highest_stage);
608 }
609 
610 /*
611  * If 2 fingers are touching the sensor then 2 peaks can be observed in the
612  * distribution.
613  * The arithmetic doesn't support to get absolute coordinates for multi-touch
614  * yet.
615  */
616 static int touchpad_check_second_peak(struct ad714x_chip *ad714x, int idx)
617 {
618 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
619 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
620 	int i;
621 
622 	for (i = hw->x_start_stage; i < sw->x_highest_stage; i++) {
623 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
624 			> (ad714x->sensor_val[i + 1] / 10))
625 			return 1;
626 	}
627 
628 	for (i = sw->x_highest_stage; i < hw->x_end_stage; i++) {
629 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
630 			> (ad714x->sensor_val[i] / 10))
631 			return 1;
632 	}
633 
634 	for (i = hw->y_start_stage; i < sw->y_highest_stage; i++) {
635 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
636 			> (ad714x->sensor_val[i + 1] / 10))
637 			return 1;
638 	}
639 
640 	for (i = sw->y_highest_stage; i < hw->y_end_stage; i++) {
641 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
642 			> (ad714x->sensor_val[i] / 10))
643 			return 1;
644 	}
645 
646 	return 0;
647 }
648 
649 /*
650  * If only one finger is used to activate the touch pad then only 1 peak will be
651  * registered in the distribution. This peak and the 2 adjacent sensors will be
652  * used in the calculation of the absolute position. This will prevent hand
653  * shadows to affect the absolute position calculation.
654  */
655 static void touchpad_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
656 {
657 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
658 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
659 
660 	sw->x_abs_pos = ad714x_cal_abs_pos(ad714x, hw->x_start_stage,
661 			hw->x_end_stage, sw->x_highest_stage, hw->x_max_coord);
662 	sw->y_abs_pos = ad714x_cal_abs_pos(ad714x, hw->y_start_stage,
663 			hw->y_end_stage, sw->y_highest_stage, hw->y_max_coord);
664 
665 	dev_dbg(ad714x->dev, "touchpad %d absolute position:(%d, %d)\n", idx,
666 			sw->x_abs_pos, sw->y_abs_pos);
667 }
668 
669 static void touchpad_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
670 {
671 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
672 
673 	sw->x_flt_pos = (sw->x_flt_pos * (10 - 4) +
674 			sw->x_abs_pos * 4)/10;
675 	sw->y_flt_pos = (sw->y_flt_pos * (10 - 4) +
676 			sw->y_abs_pos * 4)/10;
677 
678 	dev_dbg(ad714x->dev, "touchpad %d filter position:(%d, %d)\n",
679 			idx, sw->x_flt_pos, sw->y_flt_pos);
680 }
681 
682 /*
683  * To prevent distortion from showing in the absolute position, it is
684  * necessary to detect the end points. When endpoints are detected, the
685  * driver stops updating the status variables with absolute positions.
686  * End points are detected on the 4 edges of the touchpad sensor. The
687  * method to detect them is the same for all 4.
688  * To detect the end points, the firmware computes the difference in
689  * percent between the sensor on the edge and the adjacent one. The
690  * difference is calculated in percent in order to make the end point
691  * detection independent of the pressure.
692  */
693 
694 #define LEFT_END_POINT_DETECTION_LEVEL                  550
695 #define RIGHT_END_POINT_DETECTION_LEVEL                 750
696 #define LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL         850
697 #define TOP_END_POINT_DETECTION_LEVEL                   550
698 #define BOTTOM_END_POINT_DETECTION_LEVEL                950
699 #define TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL         700
700 static int touchpad_check_endpoint(struct ad714x_chip *ad714x, int idx)
701 {
702 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
703 	struct ad714x_touchpad_drv *sw  = &ad714x->sw->touchpad[idx];
704 	int percent_sensor_diff;
705 
706 	/* left endpoint detect */
707 	percent_sensor_diff = (ad714x->sensor_val[hw->x_start_stage] -
708 			ad714x->sensor_val[hw->x_start_stage + 1]) * 100 /
709 			ad714x->sensor_val[hw->x_start_stage + 1];
710 	if (!sw->left_ep) {
711 		if (percent_sensor_diff >= LEFT_END_POINT_DETECTION_LEVEL)  {
712 			sw->left_ep = 1;
713 			sw->left_ep_val =
714 				ad714x->sensor_val[hw->x_start_stage + 1];
715 		}
716 	} else {
717 		if ((percent_sensor_diff < LEFT_END_POINT_DETECTION_LEVEL) &&
718 		    (ad714x->sensor_val[hw->x_start_stage + 1] >
719 		     LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->left_ep_val))
720 			sw->left_ep = 0;
721 	}
722 
723 	/* right endpoint detect */
724 	percent_sensor_diff = (ad714x->sensor_val[hw->x_end_stage] -
725 			ad714x->sensor_val[hw->x_end_stage - 1]) * 100 /
726 			ad714x->sensor_val[hw->x_end_stage - 1];
727 	if (!sw->right_ep) {
728 		if (percent_sensor_diff >= RIGHT_END_POINT_DETECTION_LEVEL)  {
729 			sw->right_ep = 1;
730 			sw->right_ep_val =
731 				ad714x->sensor_val[hw->x_end_stage - 1];
732 		}
733 	} else {
734 		if ((percent_sensor_diff < RIGHT_END_POINT_DETECTION_LEVEL) &&
735 		(ad714x->sensor_val[hw->x_end_stage - 1] >
736 		LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->right_ep_val))
737 			sw->right_ep = 0;
738 	}
739 
740 	/* top endpoint detect */
741 	percent_sensor_diff = (ad714x->sensor_val[hw->y_start_stage] -
742 			ad714x->sensor_val[hw->y_start_stage + 1]) * 100 /
743 			ad714x->sensor_val[hw->y_start_stage + 1];
744 	if (!sw->top_ep) {
745 		if (percent_sensor_diff >= TOP_END_POINT_DETECTION_LEVEL)  {
746 			sw->top_ep = 1;
747 			sw->top_ep_val =
748 				ad714x->sensor_val[hw->y_start_stage + 1];
749 		}
750 	} else {
751 		if ((percent_sensor_diff < TOP_END_POINT_DETECTION_LEVEL) &&
752 		(ad714x->sensor_val[hw->y_start_stage + 1] >
753 		TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->top_ep_val))
754 			sw->top_ep = 0;
755 	}
756 
757 	/* bottom endpoint detect */
758 	percent_sensor_diff = (ad714x->sensor_val[hw->y_end_stage] -
759 		ad714x->sensor_val[hw->y_end_stage - 1]) * 100 /
760 		ad714x->sensor_val[hw->y_end_stage - 1];
761 	if (!sw->bottom_ep) {
762 		if (percent_sensor_diff >= BOTTOM_END_POINT_DETECTION_LEVEL)  {
763 			sw->bottom_ep = 1;
764 			sw->bottom_ep_val =
765 				ad714x->sensor_val[hw->y_end_stage - 1];
766 		}
767 	} else {
768 		if ((percent_sensor_diff < BOTTOM_END_POINT_DETECTION_LEVEL) &&
769 		(ad714x->sensor_val[hw->y_end_stage - 1] >
770 		 TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->bottom_ep_val))
771 			sw->bottom_ep = 0;
772 	}
773 
774 	return sw->left_ep || sw->right_ep || sw->top_ep || sw->bottom_ep;
775 }
776 
777 static void touchpad_use_com_int(struct ad714x_chip *ad714x, int idx)
778 {
779 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
780 
781 	ad714x_use_com_int(ad714x, hw->x_start_stage, hw->x_end_stage);
782 }
783 
784 static void touchpad_use_thr_int(struct ad714x_chip *ad714x, int idx)
785 {
786 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
787 
788 	ad714x_use_thr_int(ad714x, hw->x_start_stage, hw->x_end_stage);
789 	ad714x_use_thr_int(ad714x, hw->y_start_stage, hw->y_end_stage);
790 }
791 
792 static void ad714x_touchpad_state_machine(struct ad714x_chip *ad714x, int idx)
793 {
794 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
795 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
796 	unsigned short h_state, c_state;
797 	unsigned short mask;
798 
799 	mask = (((1 << (hw->x_end_stage + 1)) - 1) -
800 		((1 << hw->x_start_stage) - 1)) +
801 		(((1 << (hw->y_end_stage + 1)) - 1) -
802 		((1 << hw->y_start_stage) - 1));
803 
804 	h_state = ad714x->h_state & mask;
805 	c_state = ad714x->c_state & mask;
806 
807 	switch (sw->state) {
808 	case IDLE:
809 		if (h_state) {
810 			sw->state = JITTER;
811 			/* In End of Conversion interrupt mode, the AD714X
812 			 * continuously generates hardware interrupts.
813 			 */
814 			touchpad_use_com_int(ad714x, idx);
815 			dev_dbg(ad714x->dev, "touchpad %d touched\n", idx);
816 		}
817 		break;
818 
819 	case JITTER:
820 		if (c_state == mask) {
821 			touchpad_cal_sensor_val(ad714x, idx);
822 			touchpad_cal_highest_stage(ad714x, idx);
823 			if ((!touchpad_check_second_peak(ad714x, idx)) &&
824 				(!touchpad_check_endpoint(ad714x, idx))) {
825 				dev_dbg(ad714x->dev,
826 					"touchpad%d, 2 fingers or endpoint\n",
827 					idx);
828 				touchpad_cal_abs_pos(ad714x, idx);
829 				sw->x_flt_pos = sw->x_abs_pos;
830 				sw->y_flt_pos = sw->y_abs_pos;
831 				sw->state = ACTIVE;
832 			}
833 		}
834 		break;
835 
836 	case ACTIVE:
837 		if (c_state == mask) {
838 			if (h_state) {
839 				touchpad_cal_sensor_val(ad714x, idx);
840 				touchpad_cal_highest_stage(ad714x, idx);
841 				if ((!touchpad_check_second_peak(ad714x, idx))
842 				  && (!touchpad_check_endpoint(ad714x, idx))) {
843 					touchpad_cal_abs_pos(ad714x, idx);
844 					touchpad_cal_flt_pos(ad714x, idx);
845 					input_report_abs(sw->input, ABS_X,
846 						sw->x_flt_pos);
847 					input_report_abs(sw->input, ABS_Y,
848 						sw->y_flt_pos);
849 					input_report_key(sw->input, BTN_TOUCH,
850 						1);
851 				}
852 			} else {
853 				/* When the user lifts off the sensor, configure
854 				 * the AD714X back to threshold interrupt mode.
855 				 */
856 				touchpad_use_thr_int(ad714x, idx);
857 				sw->state = IDLE;
858 				input_report_key(sw->input, BTN_TOUCH, 0);
859 				dev_dbg(ad714x->dev, "touchpad %d released\n",
860 					idx);
861 			}
862 			input_sync(sw->input);
863 		}
864 		break;
865 
866 	default:
867 		break;
868 	}
869 }
870 
871 static int ad714x_hw_detect(struct ad714x_chip *ad714x)
872 {
873 	unsigned short data;
874 
875 	ad714x->read(ad714x, AD714X_PARTID_REG, &data, 1);
876 	switch (data & 0xFFF0) {
877 	case AD7142_PARTID:
878 		ad714x->product = 0x7142;
879 		ad714x->version = data & 0xF;
880 		dev_info(ad714x->dev, "found AD7142 captouch, rev:%d\n",
881 				ad714x->version);
882 		return 0;
883 
884 	case AD7143_PARTID:
885 		ad714x->product = 0x7143;
886 		ad714x->version = data & 0xF;
887 		dev_info(ad714x->dev, "found AD7143 captouch, rev:%d\n",
888 				ad714x->version);
889 		return 0;
890 
891 	case AD7147_PARTID:
892 		ad714x->product = 0x7147;
893 		ad714x->version = data & 0xF;
894 		dev_info(ad714x->dev, "found AD7147(A) captouch, rev:%d\n",
895 				ad714x->version);
896 		return 0;
897 
898 	case AD7148_PARTID:
899 		ad714x->product = 0x7148;
900 		ad714x->version = data & 0xF;
901 		dev_info(ad714x->dev, "found AD7148 captouch, rev:%d\n",
902 				ad714x->version);
903 		return 0;
904 
905 	default:
906 		dev_err(ad714x->dev,
907 			"fail to detect AD714X captouch, read ID is %04x\n",
908 			data);
909 		return -ENODEV;
910 	}
911 }
912 
913 static void ad714x_hw_init(struct ad714x_chip *ad714x)
914 {
915 	int i, j;
916 	unsigned short reg_base;
917 	unsigned short data;
918 
919 	/* configuration CDC and interrupts */
920 
921 	for (i = 0; i < STAGE_NUM; i++) {
922 		reg_base = AD714X_STAGECFG_REG + i * STAGE_CFGREG_NUM;
923 		for (j = 0; j < STAGE_CFGREG_NUM; j++)
924 			ad714x->write(ad714x, reg_base + j,
925 					ad714x->hw->stage_cfg_reg[i][j]);
926 	}
927 
928 	for (i = 0; i < SYS_CFGREG_NUM; i++)
929 		ad714x->write(ad714x, AD714X_SYSCFG_REG + i,
930 			ad714x->hw->sys_cfg_reg[i]);
931 	for (i = 0; i < SYS_CFGREG_NUM; i++)
932 		ad714x->read(ad714x, AD714X_SYSCFG_REG + i, &data, 1);
933 
934 	ad714x->write(ad714x, AD714X_STG_CAL_EN_REG, 0xFFF);
935 
936 	/* clear all interrupts */
937 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
938 }
939 
940 static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
941 {
942 	struct ad714x_chip *ad714x = data;
943 	int i;
944 
945 	mutex_lock(&ad714x->mutex);
946 
947 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
948 
949 	for (i = 0; i < ad714x->hw->button_num; i++)
950 		ad714x_button_state_machine(ad714x, i);
951 	for (i = 0; i < ad714x->hw->slider_num; i++)
952 		ad714x_slider_state_machine(ad714x, i);
953 	for (i = 0; i < ad714x->hw->wheel_num; i++)
954 		ad714x_wheel_state_machine(ad714x, i);
955 	for (i = 0; i < ad714x->hw->touchpad_num; i++)
956 		ad714x_touchpad_state_machine(ad714x, i);
957 
958 	mutex_unlock(&ad714x->mutex);
959 
960 	return IRQ_HANDLED;
961 }
962 
963 struct ad714x_chip *ad714x_probe(struct device *dev, u16 bus_type, int irq,
964 				 ad714x_read_t read, ad714x_write_t write)
965 {
966 	int i;
967 	int error;
968 	struct input_dev *input;
969 
970 	struct ad714x_platform_data *plat_data = dev_get_platdata(dev);
971 	struct ad714x_chip *ad714x;
972 	void *drv_mem;
973 	unsigned long irqflags;
974 
975 	struct ad714x_button_drv *bt_drv;
976 	struct ad714x_slider_drv *sd_drv;
977 	struct ad714x_wheel_drv *wl_drv;
978 	struct ad714x_touchpad_drv *tp_drv;
979 
980 
981 	if (irq <= 0) {
982 		dev_err(dev, "IRQ not configured!\n");
983 		error = -EINVAL;
984 		return ERR_PTR(error);
985 	}
986 
987 	if (dev_get_platdata(dev) == NULL) {
988 		dev_err(dev, "platform data for ad714x doesn't exist\n");
989 		error = -EINVAL;
990 		return ERR_PTR(error);
991 	}
992 
993 	ad714x = devm_kzalloc(dev, sizeof(*ad714x) + sizeof(*ad714x->sw) +
994 				   sizeof(*sd_drv) * plat_data->slider_num +
995 				   sizeof(*wl_drv) * plat_data->wheel_num +
996 				   sizeof(*tp_drv) * plat_data->touchpad_num +
997 				   sizeof(*bt_drv) * plat_data->button_num,
998 			      GFP_KERNEL);
999 	if (!ad714x) {
1000 		error = -ENOMEM;
1001 		return ERR_PTR(error);
1002 	}
1003 	ad714x->hw = plat_data;
1004 
1005 	drv_mem = ad714x + 1;
1006 	ad714x->sw = drv_mem;
1007 	drv_mem += sizeof(*ad714x->sw);
1008 	ad714x->sw->slider = sd_drv = drv_mem;
1009 	drv_mem += sizeof(*sd_drv) * ad714x->hw->slider_num;
1010 	ad714x->sw->wheel = wl_drv = drv_mem;
1011 	drv_mem += sizeof(*wl_drv) * ad714x->hw->wheel_num;
1012 	ad714x->sw->touchpad = tp_drv = drv_mem;
1013 	drv_mem += sizeof(*tp_drv) * ad714x->hw->touchpad_num;
1014 	ad714x->sw->button = bt_drv = drv_mem;
1015 	drv_mem += sizeof(*bt_drv) * ad714x->hw->button_num;
1016 
1017 	ad714x->read = read;
1018 	ad714x->write = write;
1019 	ad714x->irq = irq;
1020 	ad714x->dev = dev;
1021 
1022 	error = ad714x_hw_detect(ad714x);
1023 	if (error)
1024 		return ERR_PTR(error);
1025 
1026 	/* initialize and request sw/hw resources */
1027 
1028 	ad714x_hw_init(ad714x);
1029 	mutex_init(&ad714x->mutex);
1030 
1031 	/* a slider uses one input_dev instance */
1032 	if (ad714x->hw->slider_num > 0) {
1033 		struct ad714x_slider_plat *sd_plat = ad714x->hw->slider;
1034 
1035 		for (i = 0; i < ad714x->hw->slider_num; i++) {
1036 			input = devm_input_allocate_device(dev);
1037 			if (!input)
1038 				return ERR_PTR(-ENOMEM);
1039 
1040 			__set_bit(EV_ABS, input->evbit);
1041 			__set_bit(EV_KEY, input->evbit);
1042 			__set_bit(ABS_X, input->absbit);
1043 			__set_bit(BTN_TOUCH, input->keybit);
1044 			input_set_abs_params(input,
1045 				ABS_X, 0, sd_plat->max_coord, 0, 0);
1046 
1047 			input->id.bustype = bus_type;
1048 			input->id.product = ad714x->product;
1049 			input->id.version = ad714x->version;
1050 			input->name = "ad714x_captouch_slider";
1051 			input->dev.parent = dev;
1052 
1053 			error = input_register_device(input);
1054 			if (error)
1055 				return ERR_PTR(error);
1056 
1057 			sd_drv[i].input = input;
1058 		}
1059 	}
1060 
1061 	/* a wheel uses one input_dev instance */
1062 	if (ad714x->hw->wheel_num > 0) {
1063 		struct ad714x_wheel_plat *wl_plat = ad714x->hw->wheel;
1064 
1065 		for (i = 0; i < ad714x->hw->wheel_num; i++) {
1066 			input = devm_input_allocate_device(dev);
1067 			if (!input)
1068 				return ERR_PTR(-ENOMEM);
1069 
1070 			__set_bit(EV_KEY, input->evbit);
1071 			__set_bit(EV_ABS, input->evbit);
1072 			__set_bit(ABS_WHEEL, input->absbit);
1073 			__set_bit(BTN_TOUCH, input->keybit);
1074 			input_set_abs_params(input,
1075 				ABS_WHEEL, 0, wl_plat->max_coord, 0, 0);
1076 
1077 			input->id.bustype = bus_type;
1078 			input->id.product = ad714x->product;
1079 			input->id.version = ad714x->version;
1080 			input->name = "ad714x_captouch_wheel";
1081 			input->dev.parent = dev;
1082 
1083 			error = input_register_device(input);
1084 			if (error)
1085 				return ERR_PTR(error);
1086 
1087 			wl_drv[i].input = input;
1088 		}
1089 	}
1090 
1091 	/* a touchpad uses one input_dev instance */
1092 	if (ad714x->hw->touchpad_num > 0) {
1093 		struct ad714x_touchpad_plat *tp_plat = ad714x->hw->touchpad;
1094 
1095 		for (i = 0; i < ad714x->hw->touchpad_num; i++) {
1096 			input = devm_input_allocate_device(dev);
1097 			if (!input)
1098 				return ERR_PTR(-ENOMEM);
1099 
1100 			__set_bit(EV_ABS, input->evbit);
1101 			__set_bit(EV_KEY, input->evbit);
1102 			__set_bit(ABS_X, input->absbit);
1103 			__set_bit(ABS_Y, input->absbit);
1104 			__set_bit(BTN_TOUCH, input->keybit);
1105 			input_set_abs_params(input,
1106 				ABS_X, 0, tp_plat->x_max_coord, 0, 0);
1107 			input_set_abs_params(input,
1108 				ABS_Y, 0, tp_plat->y_max_coord, 0, 0);
1109 
1110 			input->id.bustype = bus_type;
1111 			input->id.product = ad714x->product;
1112 			input->id.version = ad714x->version;
1113 			input->name = "ad714x_captouch_pad";
1114 			input->dev.parent = dev;
1115 
1116 			error = input_register_device(input);
1117 			if (error)
1118 				return ERR_PTR(error);
1119 
1120 			tp_drv[i].input = input;
1121 		}
1122 	}
1123 
1124 	/* all buttons use one input node */
1125 	if (ad714x->hw->button_num > 0) {
1126 		struct ad714x_button_plat *bt_plat = ad714x->hw->button;
1127 
1128 		input = devm_input_allocate_device(dev);
1129 		if (!input) {
1130 			error = -ENOMEM;
1131 			return ERR_PTR(error);
1132 		}
1133 
1134 		__set_bit(EV_KEY, input->evbit);
1135 		for (i = 0; i < ad714x->hw->button_num; i++) {
1136 			bt_drv[i].input = input;
1137 			__set_bit(bt_plat[i].keycode, input->keybit);
1138 		}
1139 
1140 		input->id.bustype = bus_type;
1141 		input->id.product = ad714x->product;
1142 		input->id.version = ad714x->version;
1143 		input->name = "ad714x_captouch_button";
1144 		input->dev.parent = dev;
1145 
1146 		error = input_register_device(input);
1147 		if (error)
1148 			return ERR_PTR(error);
1149 	}
1150 
1151 	irqflags = plat_data->irqflags ?: IRQF_TRIGGER_FALLING;
1152 	irqflags |= IRQF_ONESHOT;
1153 
1154 	error = devm_request_threaded_irq(dev, ad714x->irq, NULL,
1155 					  ad714x_interrupt_thread,
1156 					  irqflags, "ad714x_captouch", ad714x);
1157 	if (error) {
1158 		dev_err(dev, "can't allocate irq %d\n", ad714x->irq);
1159 		return ERR_PTR(error);
1160 	}
1161 
1162 	return ad714x;
1163 }
1164 EXPORT_SYMBOL(ad714x_probe);
1165 
1166 #ifdef CONFIG_PM
1167 int ad714x_disable(struct ad714x_chip *ad714x)
1168 {
1169 	unsigned short data;
1170 
1171 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1172 
1173 	mutex_lock(&ad714x->mutex);
1174 
1175 	data = ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL] | 0x3;
1176 	ad714x->write(ad714x, AD714X_PWR_CTRL, data);
1177 
1178 	mutex_unlock(&ad714x->mutex);
1179 
1180 	return 0;
1181 }
1182 EXPORT_SYMBOL(ad714x_disable);
1183 
1184 int ad714x_enable(struct ad714x_chip *ad714x)
1185 {
1186 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1187 
1188 	mutex_lock(&ad714x->mutex);
1189 
1190 	/* resume to non-shutdown mode */
1191 
1192 	ad714x->write(ad714x, AD714X_PWR_CTRL,
1193 			ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL]);
1194 
1195 	/* make sure the interrupt output line is not low level after resume,
1196 	 * otherwise we will get no chance to enter falling-edge irq again
1197 	 */
1198 
1199 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
1200 
1201 	mutex_unlock(&ad714x->mutex);
1202 
1203 	return 0;
1204 }
1205 EXPORT_SYMBOL(ad714x_enable);
1206 #endif
1207 
1208 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor Driver");
1209 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
1210 MODULE_LICENSE("GPL");
1211