xref: /openbmc/linux/drivers/input/misc/ad714x.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * AD714X CapTouch Programmable Controller driver supporting AD7142/3/7/8/7A
4  *
5  * Copyright 2009-2011 Analog Devices Inc.
6  */
7 
8 #include <linux/device.h>
9 #include <linux/input.h>
10 #include <linux/interrupt.h>
11 #include <linux/slab.h>
12 #include <linux/input/ad714x.h>
13 #include <linux/module.h>
14 #include "ad714x.h"
15 
16 #define AD714X_PWR_CTRL           0x0
17 #define AD714X_STG_CAL_EN_REG     0x1
18 #define AD714X_AMB_COMP_CTRL0_REG 0x2
19 #define AD714X_PARTID_REG         0x17
20 #define AD7142_PARTID             0xE620
21 #define AD7143_PARTID             0xE630
22 #define AD7147_PARTID             0x1470
23 #define AD7148_PARTID             0x1480
24 #define AD714X_STAGECFG_REG       0x80
25 #define AD714X_SYSCFG_REG         0x0
26 
27 #define STG_LOW_INT_EN_REG     0x5
28 #define STG_HIGH_INT_EN_REG    0x6
29 #define STG_COM_INT_EN_REG     0x7
30 #define STG_LOW_INT_STA_REG    0x8
31 #define STG_HIGH_INT_STA_REG   0x9
32 #define STG_COM_INT_STA_REG    0xA
33 
34 #define CDC_RESULT_S0          0xB
35 #define CDC_RESULT_S1          0xC
36 #define CDC_RESULT_S2          0xD
37 #define CDC_RESULT_S3          0xE
38 #define CDC_RESULT_S4          0xF
39 #define CDC_RESULT_S5          0x10
40 #define CDC_RESULT_S6          0x11
41 #define CDC_RESULT_S7          0x12
42 #define CDC_RESULT_S8          0x13
43 #define CDC_RESULT_S9          0x14
44 #define CDC_RESULT_S10         0x15
45 #define CDC_RESULT_S11         0x16
46 
47 #define STAGE0_AMBIENT		0xF1
48 #define STAGE1_AMBIENT		0x115
49 #define STAGE2_AMBIENT		0x139
50 #define STAGE3_AMBIENT		0x15D
51 #define STAGE4_AMBIENT		0x181
52 #define STAGE5_AMBIENT		0x1A5
53 #define STAGE6_AMBIENT		0x1C9
54 #define STAGE7_AMBIENT		0x1ED
55 #define STAGE8_AMBIENT		0x211
56 #define STAGE9_AMBIENT		0x234
57 #define STAGE10_AMBIENT		0x259
58 #define STAGE11_AMBIENT		0x27D
59 
60 #define PER_STAGE_REG_NUM      36
61 #define STAGE_CFGREG_NUM       8
62 #define SYS_CFGREG_NUM         8
63 
64 /*
65  * driver information which will be used to maintain the software flow
66  */
67 enum ad714x_device_state { IDLE, JITTER, ACTIVE, SPACE };
68 
69 struct ad714x_slider_drv {
70 	int highest_stage;
71 	int abs_pos;
72 	int flt_pos;
73 	enum ad714x_device_state state;
74 	struct input_dev *input;
75 };
76 
77 struct ad714x_wheel_drv {
78 	int abs_pos;
79 	int flt_pos;
80 	int pre_highest_stage;
81 	int highest_stage;
82 	enum ad714x_device_state state;
83 	struct input_dev *input;
84 };
85 
86 struct ad714x_touchpad_drv {
87 	int x_highest_stage;
88 	int x_flt_pos;
89 	int x_abs_pos;
90 	int y_highest_stage;
91 	int y_flt_pos;
92 	int y_abs_pos;
93 	int left_ep;
94 	int left_ep_val;
95 	int right_ep;
96 	int right_ep_val;
97 	int top_ep;
98 	int top_ep_val;
99 	int bottom_ep;
100 	int bottom_ep_val;
101 	enum ad714x_device_state state;
102 	struct input_dev *input;
103 };
104 
105 struct ad714x_button_drv {
106 	enum ad714x_device_state state;
107 	/*
108 	 * Unlike slider/wheel/touchpad, all buttons point to
109 	 * same input_dev instance
110 	 */
111 	struct input_dev *input;
112 };
113 
114 struct ad714x_driver_data {
115 	struct ad714x_slider_drv *slider;
116 	struct ad714x_wheel_drv *wheel;
117 	struct ad714x_touchpad_drv *touchpad;
118 	struct ad714x_button_drv *button;
119 };
120 
121 /*
122  * information to integrate all things which will be private data
123  * of spi/i2c device
124  */
125 
126 static void ad714x_use_com_int(struct ad714x_chip *ad714x,
127 				int start_stage, int end_stage)
128 {
129 	unsigned short data;
130 	unsigned short mask;
131 
132 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
133 
134 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
135 	data |= 1 << end_stage;
136 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
137 
138 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
139 	data &= ~mask;
140 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
141 }
142 
143 static void ad714x_use_thr_int(struct ad714x_chip *ad714x,
144 				int start_stage, int end_stage)
145 {
146 	unsigned short data;
147 	unsigned short mask;
148 
149 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
150 
151 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
152 	data &= ~(1 << end_stage);
153 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
154 
155 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
156 	data |= mask;
157 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
158 }
159 
160 static int ad714x_cal_highest_stage(struct ad714x_chip *ad714x,
161 					int start_stage, int end_stage)
162 {
163 	int max_res = 0;
164 	int max_idx = 0;
165 	int i;
166 
167 	for (i = start_stage; i <= end_stage; i++) {
168 		if (ad714x->sensor_val[i] > max_res) {
169 			max_res = ad714x->sensor_val[i];
170 			max_idx = i;
171 		}
172 	}
173 
174 	return max_idx;
175 }
176 
177 static int ad714x_cal_abs_pos(struct ad714x_chip *ad714x,
178 				int start_stage, int end_stage,
179 				int highest_stage, int max_coord)
180 {
181 	int a_param, b_param;
182 
183 	if (highest_stage == start_stage) {
184 		a_param = ad714x->sensor_val[start_stage + 1];
185 		b_param = ad714x->sensor_val[start_stage] +
186 			ad714x->sensor_val[start_stage + 1];
187 	} else if (highest_stage == end_stage) {
188 		a_param = ad714x->sensor_val[end_stage] *
189 			(end_stage - start_stage) +
190 			ad714x->sensor_val[end_stage - 1] *
191 			(end_stage - start_stage - 1);
192 		b_param = ad714x->sensor_val[end_stage] +
193 			ad714x->sensor_val[end_stage - 1];
194 	} else {
195 		a_param = ad714x->sensor_val[highest_stage] *
196 			(highest_stage - start_stage) +
197 			ad714x->sensor_val[highest_stage - 1] *
198 			(highest_stage - start_stage - 1) +
199 			ad714x->sensor_val[highest_stage + 1] *
200 			(highest_stage - start_stage + 1);
201 		b_param = ad714x->sensor_val[highest_stage] +
202 			ad714x->sensor_val[highest_stage - 1] +
203 			ad714x->sensor_val[highest_stage + 1];
204 	}
205 
206 	return (max_coord / (end_stage - start_stage)) * a_param / b_param;
207 }
208 
209 /*
210  * One button can connect to multi positive and negative of CDCs
211  * Multi-buttons can connect to same positive/negative of one CDC
212  */
213 static void ad714x_button_state_machine(struct ad714x_chip *ad714x, int idx)
214 {
215 	struct ad714x_button_plat *hw = &ad714x->hw->button[idx];
216 	struct ad714x_button_drv *sw = &ad714x->sw->button[idx];
217 
218 	switch (sw->state) {
219 	case IDLE:
220 		if (((ad714x->h_state & hw->h_mask) == hw->h_mask) &&
221 		    ((ad714x->l_state & hw->l_mask) == hw->l_mask)) {
222 			dev_dbg(ad714x->dev, "button %d touched\n", idx);
223 			input_report_key(sw->input, hw->keycode, 1);
224 			input_sync(sw->input);
225 			sw->state = ACTIVE;
226 		}
227 		break;
228 
229 	case ACTIVE:
230 		if (((ad714x->h_state & hw->h_mask) != hw->h_mask) ||
231 		    ((ad714x->l_state & hw->l_mask) != hw->l_mask)) {
232 			dev_dbg(ad714x->dev, "button %d released\n", idx);
233 			input_report_key(sw->input, hw->keycode, 0);
234 			input_sync(sw->input);
235 			sw->state = IDLE;
236 		}
237 		break;
238 
239 	default:
240 		break;
241 	}
242 }
243 
244 /*
245  * The response of a sensor is defined by the absolute number of codes
246  * between the current CDC value and the ambient value.
247  */
248 static void ad714x_slider_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
249 {
250 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
251 	int i;
252 
253 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
254 			&ad714x->adc_reg[hw->start_stage],
255 			hw->end_stage - hw->start_stage + 1);
256 
257 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
258 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
259 				&ad714x->amb_reg[i], 1);
260 
261 		ad714x->sensor_val[i] =
262 			abs(ad714x->adc_reg[i] - ad714x->amb_reg[i]);
263 	}
264 }
265 
266 static void ad714x_slider_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
267 {
268 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
269 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
270 
271 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
272 			hw->end_stage);
273 
274 	dev_dbg(ad714x->dev, "slider %d highest_stage:%d\n", idx,
275 		sw->highest_stage);
276 }
277 
278 /*
279  * The formulae are very straight forward. It uses the sensor with the
280  * highest response and the 2 adjacent ones.
281  * When Sensor 0 has the highest response, only sensor 0 and sensor 1
282  * are used in the calculations. Similarly when the last sensor has the
283  * highest response, only the last sensor and the second last sensors
284  * are used in the calculations.
285  *
286  * For i= idx_of_peak_Sensor-1 to i= idx_of_peak_Sensor+1
287  *         v += Sensor response(i)*i
288  *         w += Sensor response(i)
289  * POS=(Number_of_Positions_Wanted/(Number_of_Sensors_Used-1)) *(v/w)
290  */
291 static void ad714x_slider_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
292 {
293 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
294 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
295 
296 	sw->abs_pos = ad714x_cal_abs_pos(ad714x, hw->start_stage, hw->end_stage,
297 		sw->highest_stage, hw->max_coord);
298 
299 	dev_dbg(ad714x->dev, "slider %d absolute position:%d\n", idx,
300 		sw->abs_pos);
301 }
302 
303 /*
304  * To minimise the Impact of the noise on the algorithm, ADI developed a
305  * routine that filters the CDC results after they have been read by the
306  * host processor.
307  * The filter used is an Infinite Input Response(IIR) filter implemented
308  * in firmware and attenuates the noise on the CDC results after they've
309  * been read by the host processor.
310  * Filtered_CDC_result = (Filtered_CDC_result * (10 - Coefficient) +
311  *				Latest_CDC_result * Coefficient)/10
312  */
313 static void ad714x_slider_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
314 {
315 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
316 
317 	sw->flt_pos = (sw->flt_pos * (10 - 4) +
318 			sw->abs_pos * 4)/10;
319 
320 	dev_dbg(ad714x->dev, "slider %d filter position:%d\n", idx,
321 		sw->flt_pos);
322 }
323 
324 static void ad714x_slider_use_com_int(struct ad714x_chip *ad714x, int idx)
325 {
326 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
327 
328 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
329 }
330 
331 static void ad714x_slider_use_thr_int(struct ad714x_chip *ad714x, int idx)
332 {
333 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
334 
335 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
336 }
337 
338 static void ad714x_slider_state_machine(struct ad714x_chip *ad714x, int idx)
339 {
340 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
341 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
342 	unsigned short h_state, c_state;
343 	unsigned short mask;
344 
345 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
346 
347 	h_state = ad714x->h_state & mask;
348 	c_state = ad714x->c_state & mask;
349 
350 	switch (sw->state) {
351 	case IDLE:
352 		if (h_state) {
353 			sw->state = JITTER;
354 			/* In End of Conversion interrupt mode, the AD714X
355 			 * continuously generates hardware interrupts.
356 			 */
357 			ad714x_slider_use_com_int(ad714x, idx);
358 			dev_dbg(ad714x->dev, "slider %d touched\n", idx);
359 		}
360 		break;
361 
362 	case JITTER:
363 		if (c_state == mask) {
364 			ad714x_slider_cal_sensor_val(ad714x, idx);
365 			ad714x_slider_cal_highest_stage(ad714x, idx);
366 			ad714x_slider_cal_abs_pos(ad714x, idx);
367 			sw->flt_pos = sw->abs_pos;
368 			sw->state = ACTIVE;
369 		}
370 		break;
371 
372 	case ACTIVE:
373 		if (c_state == mask) {
374 			if (h_state) {
375 				ad714x_slider_cal_sensor_val(ad714x, idx);
376 				ad714x_slider_cal_highest_stage(ad714x, idx);
377 				ad714x_slider_cal_abs_pos(ad714x, idx);
378 				ad714x_slider_cal_flt_pos(ad714x, idx);
379 				input_report_abs(sw->input, ABS_X, sw->flt_pos);
380 				input_report_key(sw->input, BTN_TOUCH, 1);
381 			} else {
382 				/* When the user lifts off the sensor, configure
383 				 * the AD714X back to threshold interrupt mode.
384 				 */
385 				ad714x_slider_use_thr_int(ad714x, idx);
386 				sw->state = IDLE;
387 				input_report_key(sw->input, BTN_TOUCH, 0);
388 				dev_dbg(ad714x->dev, "slider %d released\n",
389 					idx);
390 			}
391 			input_sync(sw->input);
392 		}
393 		break;
394 
395 	default:
396 		break;
397 	}
398 }
399 
400 /*
401  * When the scroll wheel is activated, we compute the absolute position based
402  * on the sensor values. To calculate the position, we first determine the
403  * sensor that has the greatest response among the 8 sensors that constitutes
404  * the scrollwheel. Then we determined the 2 sensors on either sides of the
405  * sensor with the highest response and we apply weights to these sensors.
406  */
407 static void ad714x_wheel_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
408 {
409 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
410 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
411 
412 	sw->pre_highest_stage = sw->highest_stage;
413 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
414 			hw->end_stage);
415 
416 	dev_dbg(ad714x->dev, "wheel %d highest_stage:%d\n", idx,
417 		sw->highest_stage);
418 }
419 
420 static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
421 {
422 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
423 	int i;
424 
425 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
426 			&ad714x->adc_reg[hw->start_stage],
427 			hw->end_stage - hw->start_stage + 1);
428 
429 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
430 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
431 				&ad714x->amb_reg[i], 1);
432 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
433 			ad714x->sensor_val[i] =
434 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
435 		else
436 			ad714x->sensor_val[i] = 0;
437 	}
438 }
439 
440 /*
441  * When the scroll wheel is activated, we compute the absolute position based
442  * on the sensor values. To calculate the position, we first determine the
443  * sensor that has the greatest response among the sensors that constitutes
444  * the scrollwheel. Then we determined the sensors on either sides of the
445  * sensor with the highest response and we apply weights to these sensors. The
446  * result of this computation gives us the mean value.
447  */
448 
449 static void ad714x_wheel_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
450 {
451 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
452 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
453 	int stage_num = hw->end_stage - hw->start_stage + 1;
454 	int first_before, highest, first_after;
455 	int a_param, b_param;
456 
457 	first_before = (sw->highest_stage + stage_num - 1) % stage_num;
458 	highest = sw->highest_stage;
459 	first_after = (sw->highest_stage + stage_num + 1) % stage_num;
460 
461 	a_param = ad714x->sensor_val[highest] *
462 		(highest - hw->start_stage) +
463 		ad714x->sensor_val[first_before] *
464 		(highest - hw->start_stage - 1) +
465 		ad714x->sensor_val[first_after] *
466 		(highest - hw->start_stage + 1);
467 	b_param = ad714x->sensor_val[highest] +
468 		ad714x->sensor_val[first_before] +
469 		ad714x->sensor_val[first_after];
470 
471 	sw->abs_pos = ((hw->max_coord / (hw->end_stage - hw->start_stage)) *
472 			a_param) / b_param;
473 
474 	if (sw->abs_pos > hw->max_coord)
475 		sw->abs_pos = hw->max_coord;
476 	else if (sw->abs_pos < 0)
477 		sw->abs_pos = 0;
478 }
479 
480 static void ad714x_wheel_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
481 {
482 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
483 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
484 	if (((sw->pre_highest_stage == hw->end_stage) &&
485 			(sw->highest_stage == hw->start_stage)) ||
486 	    ((sw->pre_highest_stage == hw->start_stage) &&
487 			(sw->highest_stage == hw->end_stage)))
488 		sw->flt_pos = sw->abs_pos;
489 	else
490 		sw->flt_pos = ((sw->flt_pos * 30) + (sw->abs_pos * 71)) / 100;
491 
492 	if (sw->flt_pos > hw->max_coord)
493 		sw->flt_pos = hw->max_coord;
494 }
495 
496 static void ad714x_wheel_use_com_int(struct ad714x_chip *ad714x, int idx)
497 {
498 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
499 
500 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
501 }
502 
503 static void ad714x_wheel_use_thr_int(struct ad714x_chip *ad714x, int idx)
504 {
505 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
506 
507 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
508 }
509 
510 static void ad714x_wheel_state_machine(struct ad714x_chip *ad714x, int idx)
511 {
512 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
513 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
514 	unsigned short h_state, c_state;
515 	unsigned short mask;
516 
517 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
518 
519 	h_state = ad714x->h_state & mask;
520 	c_state = ad714x->c_state & mask;
521 
522 	switch (sw->state) {
523 	case IDLE:
524 		if (h_state) {
525 			sw->state = JITTER;
526 			/* In End of Conversion interrupt mode, the AD714X
527 			 * continuously generates hardware interrupts.
528 			 */
529 			ad714x_wheel_use_com_int(ad714x, idx);
530 			dev_dbg(ad714x->dev, "wheel %d touched\n", idx);
531 		}
532 		break;
533 
534 	case JITTER:
535 		if (c_state == mask)	{
536 			ad714x_wheel_cal_sensor_val(ad714x, idx);
537 			ad714x_wheel_cal_highest_stage(ad714x, idx);
538 			ad714x_wheel_cal_abs_pos(ad714x, idx);
539 			sw->flt_pos = sw->abs_pos;
540 			sw->state = ACTIVE;
541 		}
542 		break;
543 
544 	case ACTIVE:
545 		if (c_state == mask) {
546 			if (h_state) {
547 				ad714x_wheel_cal_sensor_val(ad714x, idx);
548 				ad714x_wheel_cal_highest_stage(ad714x, idx);
549 				ad714x_wheel_cal_abs_pos(ad714x, idx);
550 				ad714x_wheel_cal_flt_pos(ad714x, idx);
551 				input_report_abs(sw->input, ABS_WHEEL,
552 					sw->flt_pos);
553 				input_report_key(sw->input, BTN_TOUCH, 1);
554 			} else {
555 				/* When the user lifts off the sensor, configure
556 				 * the AD714X back to threshold interrupt mode.
557 				 */
558 				ad714x_wheel_use_thr_int(ad714x, idx);
559 				sw->state = IDLE;
560 				input_report_key(sw->input, BTN_TOUCH, 0);
561 
562 				dev_dbg(ad714x->dev, "wheel %d released\n",
563 					idx);
564 			}
565 			input_sync(sw->input);
566 		}
567 		break;
568 
569 	default:
570 		break;
571 	}
572 }
573 
574 static void touchpad_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
575 {
576 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
577 	int i;
578 
579 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->x_start_stage,
580 			&ad714x->adc_reg[hw->x_start_stage],
581 			hw->x_end_stage - hw->x_start_stage + 1);
582 
583 	for (i = hw->x_start_stage; i <= hw->x_end_stage; i++) {
584 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
585 				&ad714x->amb_reg[i], 1);
586 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
587 			ad714x->sensor_val[i] =
588 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
589 		else
590 			ad714x->sensor_val[i] = 0;
591 	}
592 }
593 
594 static void touchpad_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
595 {
596 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
597 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
598 
599 	sw->x_highest_stage = ad714x_cal_highest_stage(ad714x,
600 		hw->x_start_stage, hw->x_end_stage);
601 	sw->y_highest_stage = ad714x_cal_highest_stage(ad714x,
602 		hw->y_start_stage, hw->y_end_stage);
603 
604 	dev_dbg(ad714x->dev,
605 		"touchpad %d x_highest_stage:%d, y_highest_stage:%d\n",
606 		idx, sw->x_highest_stage, sw->y_highest_stage);
607 }
608 
609 /*
610  * If 2 fingers are touching the sensor then 2 peaks can be observed in the
611  * distribution.
612  * The arithmetic doesn't support to get absolute coordinates for multi-touch
613  * yet.
614  */
615 static int touchpad_check_second_peak(struct ad714x_chip *ad714x, int idx)
616 {
617 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
618 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
619 	int i;
620 
621 	for (i = hw->x_start_stage; i < sw->x_highest_stage; i++) {
622 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
623 			> (ad714x->sensor_val[i + 1] / 10))
624 			return 1;
625 	}
626 
627 	for (i = sw->x_highest_stage; i < hw->x_end_stage; i++) {
628 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
629 			> (ad714x->sensor_val[i] / 10))
630 			return 1;
631 	}
632 
633 	for (i = hw->y_start_stage; i < sw->y_highest_stage; i++) {
634 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
635 			> (ad714x->sensor_val[i + 1] / 10))
636 			return 1;
637 	}
638 
639 	for (i = sw->y_highest_stage; i < hw->y_end_stage; i++) {
640 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
641 			> (ad714x->sensor_val[i] / 10))
642 			return 1;
643 	}
644 
645 	return 0;
646 }
647 
648 /*
649  * If only one finger is used to activate the touch pad then only 1 peak will be
650  * registered in the distribution. This peak and the 2 adjacent sensors will be
651  * used in the calculation of the absolute position. This will prevent hand
652  * shadows to affect the absolute position calculation.
653  */
654 static void touchpad_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
655 {
656 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
657 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
658 
659 	sw->x_abs_pos = ad714x_cal_abs_pos(ad714x, hw->x_start_stage,
660 			hw->x_end_stage, sw->x_highest_stage, hw->x_max_coord);
661 	sw->y_abs_pos = ad714x_cal_abs_pos(ad714x, hw->y_start_stage,
662 			hw->y_end_stage, sw->y_highest_stage, hw->y_max_coord);
663 
664 	dev_dbg(ad714x->dev, "touchpad %d absolute position:(%d, %d)\n", idx,
665 			sw->x_abs_pos, sw->y_abs_pos);
666 }
667 
668 static void touchpad_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
669 {
670 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
671 
672 	sw->x_flt_pos = (sw->x_flt_pos * (10 - 4) +
673 			sw->x_abs_pos * 4)/10;
674 	sw->y_flt_pos = (sw->y_flt_pos * (10 - 4) +
675 			sw->y_abs_pos * 4)/10;
676 
677 	dev_dbg(ad714x->dev, "touchpad %d filter position:(%d, %d)\n",
678 			idx, sw->x_flt_pos, sw->y_flt_pos);
679 }
680 
681 /*
682  * To prevent distortion from showing in the absolute position, it is
683  * necessary to detect the end points. When endpoints are detected, the
684  * driver stops updating the status variables with absolute positions.
685  * End points are detected on the 4 edges of the touchpad sensor. The
686  * method to detect them is the same for all 4.
687  * To detect the end points, the firmware computes the difference in
688  * percent between the sensor on the edge and the adjacent one. The
689  * difference is calculated in percent in order to make the end point
690  * detection independent of the pressure.
691  */
692 
693 #define LEFT_END_POINT_DETECTION_LEVEL                  550
694 #define RIGHT_END_POINT_DETECTION_LEVEL                 750
695 #define LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL         850
696 #define TOP_END_POINT_DETECTION_LEVEL                   550
697 #define BOTTOM_END_POINT_DETECTION_LEVEL                950
698 #define TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL         700
699 static int touchpad_check_endpoint(struct ad714x_chip *ad714x, int idx)
700 {
701 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
702 	struct ad714x_touchpad_drv *sw  = &ad714x->sw->touchpad[idx];
703 	int percent_sensor_diff;
704 
705 	/* left endpoint detect */
706 	percent_sensor_diff = (ad714x->sensor_val[hw->x_start_stage] -
707 			ad714x->sensor_val[hw->x_start_stage + 1]) * 100 /
708 			ad714x->sensor_val[hw->x_start_stage + 1];
709 	if (!sw->left_ep) {
710 		if (percent_sensor_diff >= LEFT_END_POINT_DETECTION_LEVEL)  {
711 			sw->left_ep = 1;
712 			sw->left_ep_val =
713 				ad714x->sensor_val[hw->x_start_stage + 1];
714 		}
715 	} else {
716 		if ((percent_sensor_diff < LEFT_END_POINT_DETECTION_LEVEL) &&
717 		    (ad714x->sensor_val[hw->x_start_stage + 1] >
718 		     LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->left_ep_val))
719 			sw->left_ep = 0;
720 	}
721 
722 	/* right endpoint detect */
723 	percent_sensor_diff = (ad714x->sensor_val[hw->x_end_stage] -
724 			ad714x->sensor_val[hw->x_end_stage - 1]) * 100 /
725 			ad714x->sensor_val[hw->x_end_stage - 1];
726 	if (!sw->right_ep) {
727 		if (percent_sensor_diff >= RIGHT_END_POINT_DETECTION_LEVEL)  {
728 			sw->right_ep = 1;
729 			sw->right_ep_val =
730 				ad714x->sensor_val[hw->x_end_stage - 1];
731 		}
732 	} else {
733 		if ((percent_sensor_diff < RIGHT_END_POINT_DETECTION_LEVEL) &&
734 		(ad714x->sensor_val[hw->x_end_stage - 1] >
735 		LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->right_ep_val))
736 			sw->right_ep = 0;
737 	}
738 
739 	/* top endpoint detect */
740 	percent_sensor_diff = (ad714x->sensor_val[hw->y_start_stage] -
741 			ad714x->sensor_val[hw->y_start_stage + 1]) * 100 /
742 			ad714x->sensor_val[hw->y_start_stage + 1];
743 	if (!sw->top_ep) {
744 		if (percent_sensor_diff >= TOP_END_POINT_DETECTION_LEVEL)  {
745 			sw->top_ep = 1;
746 			sw->top_ep_val =
747 				ad714x->sensor_val[hw->y_start_stage + 1];
748 		}
749 	} else {
750 		if ((percent_sensor_diff < TOP_END_POINT_DETECTION_LEVEL) &&
751 		(ad714x->sensor_val[hw->y_start_stage + 1] >
752 		TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->top_ep_val))
753 			sw->top_ep = 0;
754 	}
755 
756 	/* bottom endpoint detect */
757 	percent_sensor_diff = (ad714x->sensor_val[hw->y_end_stage] -
758 		ad714x->sensor_val[hw->y_end_stage - 1]) * 100 /
759 		ad714x->sensor_val[hw->y_end_stage - 1];
760 	if (!sw->bottom_ep) {
761 		if (percent_sensor_diff >= BOTTOM_END_POINT_DETECTION_LEVEL)  {
762 			sw->bottom_ep = 1;
763 			sw->bottom_ep_val =
764 				ad714x->sensor_val[hw->y_end_stage - 1];
765 		}
766 	} else {
767 		if ((percent_sensor_diff < BOTTOM_END_POINT_DETECTION_LEVEL) &&
768 		(ad714x->sensor_val[hw->y_end_stage - 1] >
769 		 TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->bottom_ep_val))
770 			sw->bottom_ep = 0;
771 	}
772 
773 	return sw->left_ep || sw->right_ep || sw->top_ep || sw->bottom_ep;
774 }
775 
776 static void touchpad_use_com_int(struct ad714x_chip *ad714x, int idx)
777 {
778 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
779 
780 	ad714x_use_com_int(ad714x, hw->x_start_stage, hw->x_end_stage);
781 }
782 
783 static void touchpad_use_thr_int(struct ad714x_chip *ad714x, int idx)
784 {
785 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
786 
787 	ad714x_use_thr_int(ad714x, hw->x_start_stage, hw->x_end_stage);
788 	ad714x_use_thr_int(ad714x, hw->y_start_stage, hw->y_end_stage);
789 }
790 
791 static void ad714x_touchpad_state_machine(struct ad714x_chip *ad714x, int idx)
792 {
793 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
794 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
795 	unsigned short h_state, c_state;
796 	unsigned short mask;
797 
798 	mask = (((1 << (hw->x_end_stage + 1)) - 1) -
799 		((1 << hw->x_start_stage) - 1)) +
800 		(((1 << (hw->y_end_stage + 1)) - 1) -
801 		((1 << hw->y_start_stage) - 1));
802 
803 	h_state = ad714x->h_state & mask;
804 	c_state = ad714x->c_state & mask;
805 
806 	switch (sw->state) {
807 	case IDLE:
808 		if (h_state) {
809 			sw->state = JITTER;
810 			/* In End of Conversion interrupt mode, the AD714X
811 			 * continuously generates hardware interrupts.
812 			 */
813 			touchpad_use_com_int(ad714x, idx);
814 			dev_dbg(ad714x->dev, "touchpad %d touched\n", idx);
815 		}
816 		break;
817 
818 	case JITTER:
819 		if (c_state == mask) {
820 			touchpad_cal_sensor_val(ad714x, idx);
821 			touchpad_cal_highest_stage(ad714x, idx);
822 			if ((!touchpad_check_second_peak(ad714x, idx)) &&
823 				(!touchpad_check_endpoint(ad714x, idx))) {
824 				dev_dbg(ad714x->dev,
825 					"touchpad%d, 2 fingers or endpoint\n",
826 					idx);
827 				touchpad_cal_abs_pos(ad714x, idx);
828 				sw->x_flt_pos = sw->x_abs_pos;
829 				sw->y_flt_pos = sw->y_abs_pos;
830 				sw->state = ACTIVE;
831 			}
832 		}
833 		break;
834 
835 	case ACTIVE:
836 		if (c_state == mask) {
837 			if (h_state) {
838 				touchpad_cal_sensor_val(ad714x, idx);
839 				touchpad_cal_highest_stage(ad714x, idx);
840 				if ((!touchpad_check_second_peak(ad714x, idx))
841 				  && (!touchpad_check_endpoint(ad714x, idx))) {
842 					touchpad_cal_abs_pos(ad714x, idx);
843 					touchpad_cal_flt_pos(ad714x, idx);
844 					input_report_abs(sw->input, ABS_X,
845 						sw->x_flt_pos);
846 					input_report_abs(sw->input, ABS_Y,
847 						sw->y_flt_pos);
848 					input_report_key(sw->input, BTN_TOUCH,
849 						1);
850 				}
851 			} else {
852 				/* When the user lifts off the sensor, configure
853 				 * the AD714X back to threshold interrupt mode.
854 				 */
855 				touchpad_use_thr_int(ad714x, idx);
856 				sw->state = IDLE;
857 				input_report_key(sw->input, BTN_TOUCH, 0);
858 				dev_dbg(ad714x->dev, "touchpad %d released\n",
859 					idx);
860 			}
861 			input_sync(sw->input);
862 		}
863 		break;
864 
865 	default:
866 		break;
867 	}
868 }
869 
870 static int ad714x_hw_detect(struct ad714x_chip *ad714x)
871 {
872 	unsigned short data;
873 
874 	ad714x->read(ad714x, AD714X_PARTID_REG, &data, 1);
875 	switch (data & 0xFFF0) {
876 	case AD7142_PARTID:
877 		ad714x->product = 0x7142;
878 		ad714x->version = data & 0xF;
879 		dev_info(ad714x->dev, "found AD7142 captouch, rev:%d\n",
880 				ad714x->version);
881 		return 0;
882 
883 	case AD7143_PARTID:
884 		ad714x->product = 0x7143;
885 		ad714x->version = data & 0xF;
886 		dev_info(ad714x->dev, "found AD7143 captouch, rev:%d\n",
887 				ad714x->version);
888 		return 0;
889 
890 	case AD7147_PARTID:
891 		ad714x->product = 0x7147;
892 		ad714x->version = data & 0xF;
893 		dev_info(ad714x->dev, "found AD7147(A) captouch, rev:%d\n",
894 				ad714x->version);
895 		return 0;
896 
897 	case AD7148_PARTID:
898 		ad714x->product = 0x7148;
899 		ad714x->version = data & 0xF;
900 		dev_info(ad714x->dev, "found AD7148 captouch, rev:%d\n",
901 				ad714x->version);
902 		return 0;
903 
904 	default:
905 		dev_err(ad714x->dev,
906 			"fail to detect AD714X captouch, read ID is %04x\n",
907 			data);
908 		return -ENODEV;
909 	}
910 }
911 
912 static void ad714x_hw_init(struct ad714x_chip *ad714x)
913 {
914 	int i, j;
915 	unsigned short reg_base;
916 	unsigned short data;
917 
918 	/* configuration CDC and interrupts */
919 
920 	for (i = 0; i < STAGE_NUM; i++) {
921 		reg_base = AD714X_STAGECFG_REG + i * STAGE_CFGREG_NUM;
922 		for (j = 0; j < STAGE_CFGREG_NUM; j++)
923 			ad714x->write(ad714x, reg_base + j,
924 					ad714x->hw->stage_cfg_reg[i][j]);
925 	}
926 
927 	for (i = 0; i < SYS_CFGREG_NUM; i++)
928 		ad714x->write(ad714x, AD714X_SYSCFG_REG + i,
929 			ad714x->hw->sys_cfg_reg[i]);
930 	for (i = 0; i < SYS_CFGREG_NUM; i++)
931 		ad714x->read(ad714x, AD714X_SYSCFG_REG + i, &data, 1);
932 
933 	ad714x->write(ad714x, AD714X_STG_CAL_EN_REG, 0xFFF);
934 
935 	/* clear all interrupts */
936 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
937 }
938 
939 static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
940 {
941 	struct ad714x_chip *ad714x = data;
942 	int i;
943 
944 	mutex_lock(&ad714x->mutex);
945 
946 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
947 
948 	for (i = 0; i < ad714x->hw->button_num; i++)
949 		ad714x_button_state_machine(ad714x, i);
950 	for (i = 0; i < ad714x->hw->slider_num; i++)
951 		ad714x_slider_state_machine(ad714x, i);
952 	for (i = 0; i < ad714x->hw->wheel_num; i++)
953 		ad714x_wheel_state_machine(ad714x, i);
954 	for (i = 0; i < ad714x->hw->touchpad_num; i++)
955 		ad714x_touchpad_state_machine(ad714x, i);
956 
957 	mutex_unlock(&ad714x->mutex);
958 
959 	return IRQ_HANDLED;
960 }
961 
962 struct ad714x_chip *ad714x_probe(struct device *dev, u16 bus_type, int irq,
963 				 ad714x_read_t read, ad714x_write_t write)
964 {
965 	int i;
966 	int error;
967 	struct input_dev *input;
968 
969 	struct ad714x_platform_data *plat_data = dev_get_platdata(dev);
970 	struct ad714x_chip *ad714x;
971 	void *drv_mem;
972 	unsigned long irqflags;
973 
974 	struct ad714x_button_drv *bt_drv;
975 	struct ad714x_slider_drv *sd_drv;
976 	struct ad714x_wheel_drv *wl_drv;
977 	struct ad714x_touchpad_drv *tp_drv;
978 
979 
980 	if (irq <= 0) {
981 		dev_err(dev, "IRQ not configured!\n");
982 		error = -EINVAL;
983 		return ERR_PTR(error);
984 	}
985 
986 	if (dev_get_platdata(dev) == NULL) {
987 		dev_err(dev, "platform data for ad714x doesn't exist\n");
988 		error = -EINVAL;
989 		return ERR_PTR(error);
990 	}
991 
992 	ad714x = devm_kzalloc(dev, sizeof(*ad714x) + sizeof(*ad714x->sw) +
993 				   sizeof(*sd_drv) * plat_data->slider_num +
994 				   sizeof(*wl_drv) * plat_data->wheel_num +
995 				   sizeof(*tp_drv) * plat_data->touchpad_num +
996 				   sizeof(*bt_drv) * plat_data->button_num,
997 			      GFP_KERNEL);
998 	if (!ad714x) {
999 		error = -ENOMEM;
1000 		return ERR_PTR(error);
1001 	}
1002 	ad714x->hw = plat_data;
1003 
1004 	drv_mem = ad714x + 1;
1005 	ad714x->sw = drv_mem;
1006 	drv_mem += sizeof(*ad714x->sw);
1007 	ad714x->sw->slider = sd_drv = drv_mem;
1008 	drv_mem += sizeof(*sd_drv) * ad714x->hw->slider_num;
1009 	ad714x->sw->wheel = wl_drv = drv_mem;
1010 	drv_mem += sizeof(*wl_drv) * ad714x->hw->wheel_num;
1011 	ad714x->sw->touchpad = tp_drv = drv_mem;
1012 	drv_mem += sizeof(*tp_drv) * ad714x->hw->touchpad_num;
1013 	ad714x->sw->button = bt_drv = drv_mem;
1014 	drv_mem += sizeof(*bt_drv) * ad714x->hw->button_num;
1015 
1016 	ad714x->read = read;
1017 	ad714x->write = write;
1018 	ad714x->irq = irq;
1019 	ad714x->dev = dev;
1020 
1021 	error = ad714x_hw_detect(ad714x);
1022 	if (error)
1023 		return ERR_PTR(error);
1024 
1025 	/* initialize and request sw/hw resources */
1026 
1027 	ad714x_hw_init(ad714x);
1028 	mutex_init(&ad714x->mutex);
1029 
1030 	/* a slider uses one input_dev instance */
1031 	if (ad714x->hw->slider_num > 0) {
1032 		struct ad714x_slider_plat *sd_plat = ad714x->hw->slider;
1033 
1034 		for (i = 0; i < ad714x->hw->slider_num; i++) {
1035 			input = devm_input_allocate_device(dev);
1036 			if (!input)
1037 				return ERR_PTR(-ENOMEM);
1038 
1039 			__set_bit(EV_ABS, input->evbit);
1040 			__set_bit(EV_KEY, input->evbit);
1041 			__set_bit(ABS_X, input->absbit);
1042 			__set_bit(BTN_TOUCH, input->keybit);
1043 			input_set_abs_params(input,
1044 				ABS_X, 0, sd_plat->max_coord, 0, 0);
1045 
1046 			input->id.bustype = bus_type;
1047 			input->id.product = ad714x->product;
1048 			input->id.version = ad714x->version;
1049 			input->name = "ad714x_captouch_slider";
1050 			input->dev.parent = dev;
1051 
1052 			error = input_register_device(input);
1053 			if (error)
1054 				return ERR_PTR(error);
1055 
1056 			sd_drv[i].input = input;
1057 		}
1058 	}
1059 
1060 	/* a wheel uses one input_dev instance */
1061 	if (ad714x->hw->wheel_num > 0) {
1062 		struct ad714x_wheel_plat *wl_plat = ad714x->hw->wheel;
1063 
1064 		for (i = 0; i < ad714x->hw->wheel_num; i++) {
1065 			input = devm_input_allocate_device(dev);
1066 			if (!input)
1067 				return ERR_PTR(-ENOMEM);
1068 
1069 			__set_bit(EV_KEY, input->evbit);
1070 			__set_bit(EV_ABS, input->evbit);
1071 			__set_bit(ABS_WHEEL, input->absbit);
1072 			__set_bit(BTN_TOUCH, input->keybit);
1073 			input_set_abs_params(input,
1074 				ABS_WHEEL, 0, wl_plat->max_coord, 0, 0);
1075 
1076 			input->id.bustype = bus_type;
1077 			input->id.product = ad714x->product;
1078 			input->id.version = ad714x->version;
1079 			input->name = "ad714x_captouch_wheel";
1080 			input->dev.parent = dev;
1081 
1082 			error = input_register_device(input);
1083 			if (error)
1084 				return ERR_PTR(error);
1085 
1086 			wl_drv[i].input = input;
1087 		}
1088 	}
1089 
1090 	/* a touchpad uses one input_dev instance */
1091 	if (ad714x->hw->touchpad_num > 0) {
1092 		struct ad714x_touchpad_plat *tp_plat = ad714x->hw->touchpad;
1093 
1094 		for (i = 0; i < ad714x->hw->touchpad_num; i++) {
1095 			input = devm_input_allocate_device(dev);
1096 			if (!input)
1097 				return ERR_PTR(-ENOMEM);
1098 
1099 			__set_bit(EV_ABS, input->evbit);
1100 			__set_bit(EV_KEY, input->evbit);
1101 			__set_bit(ABS_X, input->absbit);
1102 			__set_bit(ABS_Y, input->absbit);
1103 			__set_bit(BTN_TOUCH, input->keybit);
1104 			input_set_abs_params(input,
1105 				ABS_X, 0, tp_plat->x_max_coord, 0, 0);
1106 			input_set_abs_params(input,
1107 				ABS_Y, 0, tp_plat->y_max_coord, 0, 0);
1108 
1109 			input->id.bustype = bus_type;
1110 			input->id.product = ad714x->product;
1111 			input->id.version = ad714x->version;
1112 			input->name = "ad714x_captouch_pad";
1113 			input->dev.parent = dev;
1114 
1115 			error = input_register_device(input);
1116 			if (error)
1117 				return ERR_PTR(error);
1118 
1119 			tp_drv[i].input = input;
1120 		}
1121 	}
1122 
1123 	/* all buttons use one input node */
1124 	if (ad714x->hw->button_num > 0) {
1125 		struct ad714x_button_plat *bt_plat = ad714x->hw->button;
1126 
1127 		input = devm_input_allocate_device(dev);
1128 		if (!input) {
1129 			error = -ENOMEM;
1130 			return ERR_PTR(error);
1131 		}
1132 
1133 		__set_bit(EV_KEY, input->evbit);
1134 		for (i = 0; i < ad714x->hw->button_num; i++) {
1135 			bt_drv[i].input = input;
1136 			__set_bit(bt_plat[i].keycode, input->keybit);
1137 		}
1138 
1139 		input->id.bustype = bus_type;
1140 		input->id.product = ad714x->product;
1141 		input->id.version = ad714x->version;
1142 		input->name = "ad714x_captouch_button";
1143 		input->dev.parent = dev;
1144 
1145 		error = input_register_device(input);
1146 		if (error)
1147 			return ERR_PTR(error);
1148 	}
1149 
1150 	irqflags = plat_data->irqflags ?: IRQF_TRIGGER_FALLING;
1151 	irqflags |= IRQF_ONESHOT;
1152 
1153 	error = devm_request_threaded_irq(dev, ad714x->irq, NULL,
1154 					  ad714x_interrupt_thread,
1155 					  irqflags, "ad714x_captouch", ad714x);
1156 	if (error) {
1157 		dev_err(dev, "can't allocate irq %d\n", ad714x->irq);
1158 		return ERR_PTR(error);
1159 	}
1160 
1161 	return ad714x;
1162 }
1163 EXPORT_SYMBOL(ad714x_probe);
1164 
1165 #ifdef CONFIG_PM
1166 int ad714x_disable(struct ad714x_chip *ad714x)
1167 {
1168 	unsigned short data;
1169 
1170 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1171 
1172 	mutex_lock(&ad714x->mutex);
1173 
1174 	data = ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL] | 0x3;
1175 	ad714x->write(ad714x, AD714X_PWR_CTRL, data);
1176 
1177 	mutex_unlock(&ad714x->mutex);
1178 
1179 	return 0;
1180 }
1181 EXPORT_SYMBOL(ad714x_disable);
1182 
1183 int ad714x_enable(struct ad714x_chip *ad714x)
1184 {
1185 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1186 
1187 	mutex_lock(&ad714x->mutex);
1188 
1189 	/* resume to non-shutdown mode */
1190 
1191 	ad714x->write(ad714x, AD714X_PWR_CTRL,
1192 			ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL]);
1193 
1194 	/* make sure the interrupt output line is not low level after resume,
1195 	 * otherwise we will get no chance to enter falling-edge irq again
1196 	 */
1197 
1198 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
1199 
1200 	mutex_unlock(&ad714x->mutex);
1201 
1202 	return 0;
1203 }
1204 EXPORT_SYMBOL(ad714x_enable);
1205 #endif
1206 
1207 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor Driver");
1208 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
1209 MODULE_LICENSE("GPL");
1210