xref: /openbmc/linux/drivers/input/misc/ad714x.c (revision d0b73b48)
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/init.h>
11 #include <linux/input.h>
12 #include <linux/interrupt.h>
13 #include <linux/slab.h>
14 #include <linux/input/ad714x.h>
15 #include <linux/module.h>
16 #include "ad714x.h"
17 
18 #define AD714X_PWR_CTRL           0x0
19 #define AD714X_STG_CAL_EN_REG     0x1
20 #define AD714X_AMB_COMP_CTRL0_REG 0x2
21 #define AD714X_PARTID_REG         0x17
22 #define AD7142_PARTID             0xE620
23 #define AD7143_PARTID             0xE630
24 #define AD7147_PARTID             0x1470
25 #define AD7148_PARTID             0x1480
26 #define AD714X_STAGECFG_REG       0x80
27 #define AD714X_SYSCFG_REG         0x0
28 
29 #define STG_LOW_INT_EN_REG     0x5
30 #define STG_HIGH_INT_EN_REG    0x6
31 #define STG_COM_INT_EN_REG     0x7
32 #define STG_LOW_INT_STA_REG    0x8
33 #define STG_HIGH_INT_STA_REG   0x9
34 #define STG_COM_INT_STA_REG    0xA
35 
36 #define CDC_RESULT_S0          0xB
37 #define CDC_RESULT_S1          0xC
38 #define CDC_RESULT_S2          0xD
39 #define CDC_RESULT_S3          0xE
40 #define CDC_RESULT_S4          0xF
41 #define CDC_RESULT_S5          0x10
42 #define CDC_RESULT_S6          0x11
43 #define CDC_RESULT_S7          0x12
44 #define CDC_RESULT_S8          0x13
45 #define CDC_RESULT_S9          0x14
46 #define CDC_RESULT_S10         0x15
47 #define CDC_RESULT_S11         0x16
48 
49 #define STAGE0_AMBIENT		0xF1
50 #define STAGE1_AMBIENT		0x115
51 #define STAGE2_AMBIENT		0x139
52 #define STAGE3_AMBIENT		0x15D
53 #define STAGE4_AMBIENT		0x181
54 #define STAGE5_AMBIENT		0x1A5
55 #define STAGE6_AMBIENT		0x1C9
56 #define STAGE7_AMBIENT		0x1ED
57 #define STAGE8_AMBIENT		0x211
58 #define STAGE9_AMBIENT		0x234
59 #define STAGE10_AMBIENT		0x259
60 #define STAGE11_AMBIENT		0x27D
61 
62 #define PER_STAGE_REG_NUM      36
63 #define STAGE_CFGREG_NUM       8
64 #define SYS_CFGREG_NUM         8
65 
66 /*
67  * driver information which will be used to maintain the software flow
68  */
69 enum ad714x_device_state { IDLE, JITTER, ACTIVE, SPACE };
70 
71 struct ad714x_slider_drv {
72 	int highest_stage;
73 	int abs_pos;
74 	int flt_pos;
75 	enum ad714x_device_state state;
76 	struct input_dev *input;
77 };
78 
79 struct ad714x_wheel_drv {
80 	int abs_pos;
81 	int flt_pos;
82 	int pre_highest_stage;
83 	int highest_stage;
84 	enum ad714x_device_state state;
85 	struct input_dev *input;
86 };
87 
88 struct ad714x_touchpad_drv {
89 	int x_highest_stage;
90 	int x_flt_pos;
91 	int x_abs_pos;
92 	int y_highest_stage;
93 	int y_flt_pos;
94 	int y_abs_pos;
95 	int left_ep;
96 	int left_ep_val;
97 	int right_ep;
98 	int right_ep_val;
99 	int top_ep;
100 	int top_ep_val;
101 	int bottom_ep;
102 	int bottom_ep_val;
103 	enum ad714x_device_state state;
104 	struct input_dev *input;
105 };
106 
107 struct ad714x_button_drv {
108 	enum ad714x_device_state state;
109 	/*
110 	 * Unlike slider/wheel/touchpad, all buttons point to
111 	 * same input_dev instance
112 	 */
113 	struct input_dev *input;
114 };
115 
116 struct ad714x_driver_data {
117 	struct ad714x_slider_drv *slider;
118 	struct ad714x_wheel_drv *wheel;
119 	struct ad714x_touchpad_drv *touchpad;
120 	struct ad714x_button_drv *button;
121 };
122 
123 /*
124  * information to integrate all things which will be private data
125  * of spi/i2c device
126  */
127 
128 static void ad714x_use_com_int(struct ad714x_chip *ad714x,
129 				int start_stage, int end_stage)
130 {
131 	unsigned short data;
132 	unsigned short mask;
133 
134 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
135 
136 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
137 	data |= 1 << end_stage;
138 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
139 
140 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
141 	data &= ~mask;
142 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
143 }
144 
145 static void ad714x_use_thr_int(struct ad714x_chip *ad714x,
146 				int start_stage, int end_stage)
147 {
148 	unsigned short data;
149 	unsigned short mask;
150 
151 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
152 
153 	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data, 1);
154 	data &= ~(1 << end_stage);
155 	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
156 
157 	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data, 1);
158 	data |= mask;
159 	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
160 }
161 
162 static int ad714x_cal_highest_stage(struct ad714x_chip *ad714x,
163 					int start_stage, int end_stage)
164 {
165 	int max_res = 0;
166 	int max_idx = 0;
167 	int i;
168 
169 	for (i = start_stage; i <= end_stage; i++) {
170 		if (ad714x->sensor_val[i] > max_res) {
171 			max_res = ad714x->sensor_val[i];
172 			max_idx = i;
173 		}
174 	}
175 
176 	return max_idx;
177 }
178 
179 static int ad714x_cal_abs_pos(struct ad714x_chip *ad714x,
180 				int start_stage, int end_stage,
181 				int highest_stage, int max_coord)
182 {
183 	int a_param, b_param;
184 
185 	if (highest_stage == start_stage) {
186 		a_param = ad714x->sensor_val[start_stage + 1];
187 		b_param = ad714x->sensor_val[start_stage] +
188 			ad714x->sensor_val[start_stage + 1];
189 	} else if (highest_stage == end_stage) {
190 		a_param = ad714x->sensor_val[end_stage] *
191 			(end_stage - start_stage) +
192 			ad714x->sensor_val[end_stage - 1] *
193 			(end_stage - start_stage - 1);
194 		b_param = ad714x->sensor_val[end_stage] +
195 			ad714x->sensor_val[end_stage - 1];
196 	} else {
197 		a_param = ad714x->sensor_val[highest_stage] *
198 			(highest_stage - start_stage) +
199 			ad714x->sensor_val[highest_stage - 1] *
200 			(highest_stage - start_stage - 1) +
201 			ad714x->sensor_val[highest_stage + 1] *
202 			(highest_stage - start_stage + 1);
203 		b_param = ad714x->sensor_val[highest_stage] +
204 			ad714x->sensor_val[highest_stage - 1] +
205 			ad714x->sensor_val[highest_stage + 1];
206 	}
207 
208 	return (max_coord / (end_stage - start_stage)) * a_param / b_param;
209 }
210 
211 /*
212  * One button can connect to multi positive and negative of CDCs
213  * Multi-buttons can connect to same positive/negative of one CDC
214  */
215 static void ad714x_button_state_machine(struct ad714x_chip *ad714x, int idx)
216 {
217 	struct ad714x_button_plat *hw = &ad714x->hw->button[idx];
218 	struct ad714x_button_drv *sw = &ad714x->sw->button[idx];
219 
220 	switch (sw->state) {
221 	case IDLE:
222 		if (((ad714x->h_state & hw->h_mask) == hw->h_mask) &&
223 		    ((ad714x->l_state & hw->l_mask) == hw->l_mask)) {
224 			dev_dbg(ad714x->dev, "button %d touched\n", idx);
225 			input_report_key(sw->input, hw->keycode, 1);
226 			input_sync(sw->input);
227 			sw->state = ACTIVE;
228 		}
229 		break;
230 
231 	case ACTIVE:
232 		if (((ad714x->h_state & hw->h_mask) != hw->h_mask) ||
233 		    ((ad714x->l_state & hw->l_mask) != hw->l_mask)) {
234 			dev_dbg(ad714x->dev, "button %d released\n", idx);
235 			input_report_key(sw->input, hw->keycode, 0);
236 			input_sync(sw->input);
237 			sw->state = IDLE;
238 		}
239 		break;
240 
241 	default:
242 		break;
243 	}
244 }
245 
246 /*
247  * The response of a sensor is defined by the absolute number of codes
248  * between the current CDC value and the ambient value.
249  */
250 static void ad714x_slider_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
251 {
252 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
253 	int i;
254 
255 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
256 			&ad714x->adc_reg[hw->start_stage],
257 			hw->end_stage - hw->start_stage + 1);
258 
259 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
260 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
261 				&ad714x->amb_reg[i], 1);
262 
263 		ad714x->sensor_val[i] =
264 			abs(ad714x->adc_reg[i] - ad714x->amb_reg[i]);
265 	}
266 }
267 
268 static void ad714x_slider_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
269 {
270 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
271 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
272 
273 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
274 			hw->end_stage);
275 
276 	dev_dbg(ad714x->dev, "slider %d highest_stage:%d\n", idx,
277 		sw->highest_stage);
278 }
279 
280 /*
281  * The formulae are very straight forward. It uses the sensor with the
282  * highest response and the 2 adjacent ones.
283  * When Sensor 0 has the highest response, only sensor 0 and sensor 1
284  * are used in the calculations. Similarly when the last sensor has the
285  * highest response, only the last sensor and the second last sensors
286  * are used in the calculations.
287  *
288  * For i= idx_of_peak_Sensor-1 to i= idx_of_peak_Sensor+1
289  *         v += Sensor response(i)*i
290  *         w += Sensor response(i)
291  * POS=(Number_of_Positions_Wanted/(Number_of_Sensors_Used-1)) *(v/w)
292  */
293 static void ad714x_slider_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
294 {
295 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
296 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
297 
298 	sw->abs_pos = ad714x_cal_abs_pos(ad714x, hw->start_stage, hw->end_stage,
299 		sw->highest_stage, hw->max_coord);
300 
301 	dev_dbg(ad714x->dev, "slider %d absolute position:%d\n", idx,
302 		sw->abs_pos);
303 }
304 
305 /*
306  * To minimise the Impact of the noise on the algorithm, ADI developed a
307  * routine that filters the CDC results after they have been read by the
308  * host processor.
309  * The filter used is an Infinite Input Response(IIR) filter implemented
310  * in firmware and attenuates the noise on the CDC results after they've
311  * been read by the host processor.
312  * Filtered_CDC_result = (Filtered_CDC_result * (10 - Coefficient) +
313  *				Latest_CDC_result * Coefficient)/10
314  */
315 static void ad714x_slider_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
316 {
317 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
318 
319 	sw->flt_pos = (sw->flt_pos * (10 - 4) +
320 			sw->abs_pos * 4)/10;
321 
322 	dev_dbg(ad714x->dev, "slider %d filter position:%d\n", idx,
323 		sw->flt_pos);
324 }
325 
326 static void ad714x_slider_use_com_int(struct ad714x_chip *ad714x, int idx)
327 {
328 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
329 
330 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
331 }
332 
333 static void ad714x_slider_use_thr_int(struct ad714x_chip *ad714x, int idx)
334 {
335 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
336 
337 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
338 }
339 
340 static void ad714x_slider_state_machine(struct ad714x_chip *ad714x, int idx)
341 {
342 	struct ad714x_slider_plat *hw = &ad714x->hw->slider[idx];
343 	struct ad714x_slider_drv *sw = &ad714x->sw->slider[idx];
344 	unsigned short h_state, c_state;
345 	unsigned short mask;
346 
347 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
348 
349 	h_state = ad714x->h_state & mask;
350 	c_state = ad714x->c_state & mask;
351 
352 	switch (sw->state) {
353 	case IDLE:
354 		if (h_state) {
355 			sw->state = JITTER;
356 			/* In End of Conversion interrupt mode, the AD714X
357 			 * continuously generates hardware interrupts.
358 			 */
359 			ad714x_slider_use_com_int(ad714x, idx);
360 			dev_dbg(ad714x->dev, "slider %d touched\n", idx);
361 		}
362 		break;
363 
364 	case JITTER:
365 		if (c_state == mask) {
366 			ad714x_slider_cal_sensor_val(ad714x, idx);
367 			ad714x_slider_cal_highest_stage(ad714x, idx);
368 			ad714x_slider_cal_abs_pos(ad714x, idx);
369 			sw->flt_pos = sw->abs_pos;
370 			sw->state = ACTIVE;
371 		}
372 		break;
373 
374 	case ACTIVE:
375 		if (c_state == mask) {
376 			if (h_state) {
377 				ad714x_slider_cal_sensor_val(ad714x, idx);
378 				ad714x_slider_cal_highest_stage(ad714x, idx);
379 				ad714x_slider_cal_abs_pos(ad714x, idx);
380 				ad714x_slider_cal_flt_pos(ad714x, idx);
381 				input_report_abs(sw->input, ABS_X, sw->flt_pos);
382 				input_report_key(sw->input, BTN_TOUCH, 1);
383 			} else {
384 				/* When the user lifts off the sensor, configure
385 				 * the AD714X back to threshold interrupt mode.
386 				 */
387 				ad714x_slider_use_thr_int(ad714x, idx);
388 				sw->state = IDLE;
389 				input_report_key(sw->input, BTN_TOUCH, 0);
390 				dev_dbg(ad714x->dev, "slider %d released\n",
391 					idx);
392 			}
393 			input_sync(sw->input);
394 		}
395 		break;
396 
397 	default:
398 		break;
399 	}
400 }
401 
402 /*
403  * When the scroll wheel is activated, we compute the absolute position based
404  * on the sensor values. To calculate the position, we first determine the
405  * sensor that has the greatest response among the 8 sensors that constitutes
406  * the scrollwheel. Then we determined the 2 sensors on either sides of the
407  * sensor with the highest response and we apply weights to these sensors.
408  */
409 static void ad714x_wheel_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
410 {
411 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
412 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
413 
414 	sw->pre_highest_stage = sw->highest_stage;
415 	sw->highest_stage = ad714x_cal_highest_stage(ad714x, hw->start_stage,
416 			hw->end_stage);
417 
418 	dev_dbg(ad714x->dev, "wheel %d highest_stage:%d\n", idx,
419 		sw->highest_stage);
420 }
421 
422 static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
423 {
424 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
425 	int i;
426 
427 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->start_stage,
428 			&ad714x->adc_reg[hw->start_stage],
429 			hw->end_stage - hw->start_stage + 1);
430 
431 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
432 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
433 				&ad714x->amb_reg[i], 1);
434 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
435 			ad714x->sensor_val[i] =
436 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
437 		else
438 			ad714x->sensor_val[i] = 0;
439 	}
440 }
441 
442 /*
443  * When the scroll wheel is activated, we compute the absolute position based
444  * on the sensor values. To calculate the position, we first determine the
445  * sensor that has the greatest response among the sensors that constitutes
446  * the scrollwheel. Then we determined the sensors on either sides of the
447  * sensor with the highest response and we apply weights to these sensors. The
448  * result of this computation gives us the mean value.
449  */
450 
451 static void ad714x_wheel_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
452 {
453 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
454 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
455 	int stage_num = hw->end_stage - hw->start_stage + 1;
456 	int first_before, highest, first_after;
457 	int a_param, b_param;
458 
459 	first_before = (sw->highest_stage + stage_num - 1) % stage_num;
460 	highest = sw->highest_stage;
461 	first_after = (sw->highest_stage + stage_num + 1) % stage_num;
462 
463 	a_param = ad714x->sensor_val[highest] *
464 		(highest - hw->start_stage) +
465 		ad714x->sensor_val[first_before] *
466 		(highest - hw->start_stage - 1) +
467 		ad714x->sensor_val[first_after] *
468 		(highest - hw->start_stage + 1);
469 	b_param = ad714x->sensor_val[highest] +
470 		ad714x->sensor_val[first_before] +
471 		ad714x->sensor_val[first_after];
472 
473 	sw->abs_pos = ((hw->max_coord / (hw->end_stage - hw->start_stage)) *
474 			a_param) / b_param;
475 
476 	if (sw->abs_pos > hw->max_coord)
477 		sw->abs_pos = hw->max_coord;
478 	else if (sw->abs_pos < 0)
479 		sw->abs_pos = 0;
480 }
481 
482 static void ad714x_wheel_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
483 {
484 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
485 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
486 	if (((sw->pre_highest_stage == hw->end_stage) &&
487 			(sw->highest_stage == hw->start_stage)) ||
488 	    ((sw->pre_highest_stage == hw->start_stage) &&
489 			(sw->highest_stage == hw->end_stage)))
490 		sw->flt_pos = sw->abs_pos;
491 	else
492 		sw->flt_pos = ((sw->flt_pos * 30) + (sw->abs_pos * 71)) / 100;
493 
494 	if (sw->flt_pos > hw->max_coord)
495 		sw->flt_pos = hw->max_coord;
496 }
497 
498 static void ad714x_wheel_use_com_int(struct ad714x_chip *ad714x, int idx)
499 {
500 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
501 
502 	ad714x_use_com_int(ad714x, hw->start_stage, hw->end_stage);
503 }
504 
505 static void ad714x_wheel_use_thr_int(struct ad714x_chip *ad714x, int idx)
506 {
507 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
508 
509 	ad714x_use_thr_int(ad714x, hw->start_stage, hw->end_stage);
510 }
511 
512 static void ad714x_wheel_state_machine(struct ad714x_chip *ad714x, int idx)
513 {
514 	struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
515 	struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
516 	unsigned short h_state, c_state;
517 	unsigned short mask;
518 
519 	mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
520 
521 	h_state = ad714x->h_state & mask;
522 	c_state = ad714x->c_state & mask;
523 
524 	switch (sw->state) {
525 	case IDLE:
526 		if (h_state) {
527 			sw->state = JITTER;
528 			/* In End of Conversion interrupt mode, the AD714X
529 			 * continuously generates hardware interrupts.
530 			 */
531 			ad714x_wheel_use_com_int(ad714x, idx);
532 			dev_dbg(ad714x->dev, "wheel %d touched\n", idx);
533 		}
534 		break;
535 
536 	case JITTER:
537 		if (c_state == mask)	{
538 			ad714x_wheel_cal_sensor_val(ad714x, idx);
539 			ad714x_wheel_cal_highest_stage(ad714x, idx);
540 			ad714x_wheel_cal_abs_pos(ad714x, idx);
541 			sw->flt_pos = sw->abs_pos;
542 			sw->state = ACTIVE;
543 		}
544 		break;
545 
546 	case ACTIVE:
547 		if (c_state == mask) {
548 			if (h_state) {
549 				ad714x_wheel_cal_sensor_val(ad714x, idx);
550 				ad714x_wheel_cal_highest_stage(ad714x, idx);
551 				ad714x_wheel_cal_abs_pos(ad714x, idx);
552 				ad714x_wheel_cal_flt_pos(ad714x, idx);
553 				input_report_abs(sw->input, ABS_WHEEL,
554 					sw->flt_pos);
555 				input_report_key(sw->input, BTN_TOUCH, 1);
556 			} else {
557 				/* When the user lifts off the sensor, configure
558 				 * the AD714X back to threshold interrupt mode.
559 				 */
560 				ad714x_wheel_use_thr_int(ad714x, idx);
561 				sw->state = IDLE;
562 				input_report_key(sw->input, BTN_TOUCH, 0);
563 
564 				dev_dbg(ad714x->dev, "wheel %d released\n",
565 					idx);
566 			}
567 			input_sync(sw->input);
568 		}
569 		break;
570 
571 	default:
572 		break;
573 	}
574 }
575 
576 static void touchpad_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
577 {
578 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
579 	int i;
580 
581 	ad714x->read(ad714x, CDC_RESULT_S0 + hw->x_start_stage,
582 			&ad714x->adc_reg[hw->x_start_stage],
583 			hw->x_end_stage - hw->x_start_stage + 1);
584 
585 	for (i = hw->x_start_stage; i <= hw->x_end_stage; i++) {
586 		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
587 				&ad714x->amb_reg[i], 1);
588 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
589 			ad714x->sensor_val[i] =
590 				ad714x->adc_reg[i] - ad714x->amb_reg[i];
591 		else
592 			ad714x->sensor_val[i] = 0;
593 	}
594 }
595 
596 static void touchpad_cal_highest_stage(struct ad714x_chip *ad714x, int idx)
597 {
598 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
599 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
600 
601 	sw->x_highest_stage = ad714x_cal_highest_stage(ad714x,
602 		hw->x_start_stage, hw->x_end_stage);
603 	sw->y_highest_stage = ad714x_cal_highest_stage(ad714x,
604 		hw->y_start_stage, hw->y_end_stage);
605 
606 	dev_dbg(ad714x->dev,
607 		"touchpad %d x_highest_stage:%d, y_highest_stage:%d\n",
608 		idx, sw->x_highest_stage, sw->y_highest_stage);
609 }
610 
611 /*
612  * If 2 fingers are touching the sensor then 2 peaks can be observed in the
613  * distribution.
614  * The arithmetic doesn't support to get absolute coordinates for multi-touch
615  * yet.
616  */
617 static int touchpad_check_second_peak(struct ad714x_chip *ad714x, int idx)
618 {
619 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
620 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
621 	int i;
622 
623 	for (i = hw->x_start_stage; i < sw->x_highest_stage; i++) {
624 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
625 			> (ad714x->sensor_val[i + 1] / 10))
626 			return 1;
627 	}
628 
629 	for (i = sw->x_highest_stage; i < hw->x_end_stage; i++) {
630 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
631 			> (ad714x->sensor_val[i] / 10))
632 			return 1;
633 	}
634 
635 	for (i = hw->y_start_stage; i < sw->y_highest_stage; i++) {
636 		if ((ad714x->sensor_val[i] - ad714x->sensor_val[i + 1])
637 			> (ad714x->sensor_val[i + 1] / 10))
638 			return 1;
639 	}
640 
641 	for (i = sw->y_highest_stage; i < hw->y_end_stage; i++) {
642 		if ((ad714x->sensor_val[i + 1] - ad714x->sensor_val[i])
643 			> (ad714x->sensor_val[i] / 10))
644 			return 1;
645 	}
646 
647 	return 0;
648 }
649 
650 /*
651  * If only one finger is used to activate the touch pad then only 1 peak will be
652  * registered in the distribution. This peak and the 2 adjacent sensors will be
653  * used in the calculation of the absolute position. This will prevent hand
654  * shadows to affect the absolute position calculation.
655  */
656 static void touchpad_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
657 {
658 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
659 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
660 
661 	sw->x_abs_pos = ad714x_cal_abs_pos(ad714x, hw->x_start_stage,
662 			hw->x_end_stage, sw->x_highest_stage, hw->x_max_coord);
663 	sw->y_abs_pos = ad714x_cal_abs_pos(ad714x, hw->y_start_stage,
664 			hw->y_end_stage, sw->y_highest_stage, hw->y_max_coord);
665 
666 	dev_dbg(ad714x->dev, "touchpad %d absolute position:(%d, %d)\n", idx,
667 			sw->x_abs_pos, sw->y_abs_pos);
668 }
669 
670 static void touchpad_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
671 {
672 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
673 
674 	sw->x_flt_pos = (sw->x_flt_pos * (10 - 4) +
675 			sw->x_abs_pos * 4)/10;
676 	sw->y_flt_pos = (sw->y_flt_pos * (10 - 4) +
677 			sw->y_abs_pos * 4)/10;
678 
679 	dev_dbg(ad714x->dev, "touchpad %d filter position:(%d, %d)\n",
680 			idx, sw->x_flt_pos, sw->y_flt_pos);
681 }
682 
683 /*
684  * To prevent distortion from showing in the absolute position, it is
685  * necessary to detect the end points. When endpoints are detected, the
686  * driver stops updating the status variables with absolute positions.
687  * End points are detected on the 4 edges of the touchpad sensor. The
688  * method to detect them is the same for all 4.
689  * To detect the end points, the firmware computes the difference in
690  * percent between the sensor on the edge and the adjacent one. The
691  * difference is calculated in percent in order to make the end point
692  * detection independent of the pressure.
693  */
694 
695 #define LEFT_END_POINT_DETECTION_LEVEL                  550
696 #define RIGHT_END_POINT_DETECTION_LEVEL                 750
697 #define LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL         850
698 #define TOP_END_POINT_DETECTION_LEVEL                   550
699 #define BOTTOM_END_POINT_DETECTION_LEVEL                950
700 #define TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL         700
701 static int touchpad_check_endpoint(struct ad714x_chip *ad714x, int idx)
702 {
703 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
704 	struct ad714x_touchpad_drv *sw  = &ad714x->sw->touchpad[idx];
705 	int percent_sensor_diff;
706 
707 	/* left endpoint detect */
708 	percent_sensor_diff = (ad714x->sensor_val[hw->x_start_stage] -
709 			ad714x->sensor_val[hw->x_start_stage + 1]) * 100 /
710 			ad714x->sensor_val[hw->x_start_stage + 1];
711 	if (!sw->left_ep) {
712 		if (percent_sensor_diff >= LEFT_END_POINT_DETECTION_LEVEL)  {
713 			sw->left_ep = 1;
714 			sw->left_ep_val =
715 				ad714x->sensor_val[hw->x_start_stage + 1];
716 		}
717 	} else {
718 		if ((percent_sensor_diff < LEFT_END_POINT_DETECTION_LEVEL) &&
719 		    (ad714x->sensor_val[hw->x_start_stage + 1] >
720 		     LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->left_ep_val))
721 			sw->left_ep = 0;
722 	}
723 
724 	/* right endpoint detect */
725 	percent_sensor_diff = (ad714x->sensor_val[hw->x_end_stage] -
726 			ad714x->sensor_val[hw->x_end_stage - 1]) * 100 /
727 			ad714x->sensor_val[hw->x_end_stage - 1];
728 	if (!sw->right_ep) {
729 		if (percent_sensor_diff >= RIGHT_END_POINT_DETECTION_LEVEL)  {
730 			sw->right_ep = 1;
731 			sw->right_ep_val =
732 				ad714x->sensor_val[hw->x_end_stage - 1];
733 		}
734 	} else {
735 		if ((percent_sensor_diff < RIGHT_END_POINT_DETECTION_LEVEL) &&
736 		(ad714x->sensor_val[hw->x_end_stage - 1] >
737 		LEFT_RIGHT_END_POINT_DEAVTIVALION_LEVEL + sw->right_ep_val))
738 			sw->right_ep = 0;
739 	}
740 
741 	/* top endpoint detect */
742 	percent_sensor_diff = (ad714x->sensor_val[hw->y_start_stage] -
743 			ad714x->sensor_val[hw->y_start_stage + 1]) * 100 /
744 			ad714x->sensor_val[hw->y_start_stage + 1];
745 	if (!sw->top_ep) {
746 		if (percent_sensor_diff >= TOP_END_POINT_DETECTION_LEVEL)  {
747 			sw->top_ep = 1;
748 			sw->top_ep_val =
749 				ad714x->sensor_val[hw->y_start_stage + 1];
750 		}
751 	} else {
752 		if ((percent_sensor_diff < TOP_END_POINT_DETECTION_LEVEL) &&
753 		(ad714x->sensor_val[hw->y_start_stage + 1] >
754 		TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->top_ep_val))
755 			sw->top_ep = 0;
756 	}
757 
758 	/* bottom endpoint detect */
759 	percent_sensor_diff = (ad714x->sensor_val[hw->y_end_stage] -
760 		ad714x->sensor_val[hw->y_end_stage - 1]) * 100 /
761 		ad714x->sensor_val[hw->y_end_stage - 1];
762 	if (!sw->bottom_ep) {
763 		if (percent_sensor_diff >= BOTTOM_END_POINT_DETECTION_LEVEL)  {
764 			sw->bottom_ep = 1;
765 			sw->bottom_ep_val =
766 				ad714x->sensor_val[hw->y_end_stage - 1];
767 		}
768 	} else {
769 		if ((percent_sensor_diff < BOTTOM_END_POINT_DETECTION_LEVEL) &&
770 		(ad714x->sensor_val[hw->y_end_stage - 1] >
771 		 TOP_BOTTOM_END_POINT_DEAVTIVALION_LEVEL + sw->bottom_ep_val))
772 			sw->bottom_ep = 0;
773 	}
774 
775 	return sw->left_ep || sw->right_ep || sw->top_ep || sw->bottom_ep;
776 }
777 
778 static void touchpad_use_com_int(struct ad714x_chip *ad714x, int idx)
779 {
780 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
781 
782 	ad714x_use_com_int(ad714x, hw->x_start_stage, hw->x_end_stage);
783 }
784 
785 static void touchpad_use_thr_int(struct ad714x_chip *ad714x, int idx)
786 {
787 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
788 
789 	ad714x_use_thr_int(ad714x, hw->x_start_stage, hw->x_end_stage);
790 	ad714x_use_thr_int(ad714x, hw->y_start_stage, hw->y_end_stage);
791 }
792 
793 static void ad714x_touchpad_state_machine(struct ad714x_chip *ad714x, int idx)
794 {
795 	struct ad714x_touchpad_plat *hw = &ad714x->hw->touchpad[idx];
796 	struct ad714x_touchpad_drv *sw = &ad714x->sw->touchpad[idx];
797 	unsigned short h_state, c_state;
798 	unsigned short mask;
799 
800 	mask = (((1 << (hw->x_end_stage + 1)) - 1) -
801 		((1 << hw->x_start_stage) - 1)) +
802 		(((1 << (hw->y_end_stage + 1)) - 1) -
803 		((1 << hw->y_start_stage) - 1));
804 
805 	h_state = ad714x->h_state & mask;
806 	c_state = ad714x->c_state & mask;
807 
808 	switch (sw->state) {
809 	case IDLE:
810 		if (h_state) {
811 			sw->state = JITTER;
812 			/* In End of Conversion interrupt mode, the AD714X
813 			 * continuously generates hardware interrupts.
814 			 */
815 			touchpad_use_com_int(ad714x, idx);
816 			dev_dbg(ad714x->dev, "touchpad %d touched\n", idx);
817 		}
818 		break;
819 
820 	case JITTER:
821 		if (c_state == mask) {
822 			touchpad_cal_sensor_val(ad714x, idx);
823 			touchpad_cal_highest_stage(ad714x, idx);
824 			if ((!touchpad_check_second_peak(ad714x, idx)) &&
825 				(!touchpad_check_endpoint(ad714x, idx))) {
826 				dev_dbg(ad714x->dev,
827 					"touchpad%d, 2 fingers or endpoint\n",
828 					idx);
829 				touchpad_cal_abs_pos(ad714x, idx);
830 				sw->x_flt_pos = sw->x_abs_pos;
831 				sw->y_flt_pos = sw->y_abs_pos;
832 				sw->state = ACTIVE;
833 			}
834 		}
835 		break;
836 
837 	case ACTIVE:
838 		if (c_state == mask) {
839 			if (h_state) {
840 				touchpad_cal_sensor_val(ad714x, idx);
841 				touchpad_cal_highest_stage(ad714x, idx);
842 				if ((!touchpad_check_second_peak(ad714x, idx))
843 				  && (!touchpad_check_endpoint(ad714x, idx))) {
844 					touchpad_cal_abs_pos(ad714x, idx);
845 					touchpad_cal_flt_pos(ad714x, idx);
846 					input_report_abs(sw->input, ABS_X,
847 						sw->x_flt_pos);
848 					input_report_abs(sw->input, ABS_Y,
849 						sw->y_flt_pos);
850 					input_report_key(sw->input, BTN_TOUCH,
851 						1);
852 				}
853 			} else {
854 				/* When the user lifts off the sensor, configure
855 				 * the AD714X back to threshold interrupt mode.
856 				 */
857 				touchpad_use_thr_int(ad714x, idx);
858 				sw->state = IDLE;
859 				input_report_key(sw->input, BTN_TOUCH, 0);
860 				dev_dbg(ad714x->dev, "touchpad %d released\n",
861 					idx);
862 			}
863 			input_sync(sw->input);
864 		}
865 		break;
866 
867 	default:
868 		break;
869 	}
870 }
871 
872 static int ad714x_hw_detect(struct ad714x_chip *ad714x)
873 {
874 	unsigned short data;
875 
876 	ad714x->read(ad714x, AD714X_PARTID_REG, &data, 1);
877 	switch (data & 0xFFF0) {
878 	case AD7142_PARTID:
879 		ad714x->product = 0x7142;
880 		ad714x->version = data & 0xF;
881 		dev_info(ad714x->dev, "found AD7142 captouch, rev:%d\n",
882 				ad714x->version);
883 		return 0;
884 
885 	case AD7143_PARTID:
886 		ad714x->product = 0x7143;
887 		ad714x->version = data & 0xF;
888 		dev_info(ad714x->dev, "found AD7143 captouch, rev:%d\n",
889 				ad714x->version);
890 		return 0;
891 
892 	case AD7147_PARTID:
893 		ad714x->product = 0x7147;
894 		ad714x->version = data & 0xF;
895 		dev_info(ad714x->dev, "found AD7147(A) captouch, rev:%d\n",
896 				ad714x->version);
897 		return 0;
898 
899 	case AD7148_PARTID:
900 		ad714x->product = 0x7148;
901 		ad714x->version = data & 0xF;
902 		dev_info(ad714x->dev, "found AD7148 captouch, rev:%d\n",
903 				ad714x->version);
904 		return 0;
905 
906 	default:
907 		dev_err(ad714x->dev,
908 			"fail to detect AD714X captouch, read ID is %04x\n",
909 			data);
910 		return -ENODEV;
911 	}
912 }
913 
914 static void ad714x_hw_init(struct ad714x_chip *ad714x)
915 {
916 	int i, j;
917 	unsigned short reg_base;
918 	unsigned short data;
919 
920 	/* configuration CDC and interrupts */
921 
922 	for (i = 0; i < STAGE_NUM; i++) {
923 		reg_base = AD714X_STAGECFG_REG + i * STAGE_CFGREG_NUM;
924 		for (j = 0; j < STAGE_CFGREG_NUM; j++)
925 			ad714x->write(ad714x, reg_base + j,
926 					ad714x->hw->stage_cfg_reg[i][j]);
927 	}
928 
929 	for (i = 0; i < SYS_CFGREG_NUM; i++)
930 		ad714x->write(ad714x, AD714X_SYSCFG_REG + i,
931 			ad714x->hw->sys_cfg_reg[i]);
932 	for (i = 0; i < SYS_CFGREG_NUM; i++)
933 		ad714x->read(ad714x, AD714X_SYSCFG_REG + i, &data, 1);
934 
935 	ad714x->write(ad714x, AD714X_STG_CAL_EN_REG, 0xFFF);
936 
937 	/* clear all interrupts */
938 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
939 }
940 
941 static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
942 {
943 	struct ad714x_chip *ad714x = data;
944 	int i;
945 
946 	mutex_lock(&ad714x->mutex);
947 
948 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
949 
950 	for (i = 0; i < ad714x->hw->button_num; i++)
951 		ad714x_button_state_machine(ad714x, i);
952 	for (i = 0; i < ad714x->hw->slider_num; i++)
953 		ad714x_slider_state_machine(ad714x, i);
954 	for (i = 0; i < ad714x->hw->wheel_num; i++)
955 		ad714x_wheel_state_machine(ad714x, i);
956 	for (i = 0; i < ad714x->hw->touchpad_num; i++)
957 		ad714x_touchpad_state_machine(ad714x, i);
958 
959 	mutex_unlock(&ad714x->mutex);
960 
961 	return IRQ_HANDLED;
962 }
963 
964 #define MAX_DEVICE_NUM 8
965 struct ad714x_chip *ad714x_probe(struct device *dev, u16 bus_type, int irq,
966 				 ad714x_read_t read, ad714x_write_t write)
967 {
968 	int i, alloc_idx;
969 	int error;
970 	struct input_dev *input[MAX_DEVICE_NUM];
971 
972 	struct ad714x_platform_data *plat_data = dev->platform_data;
973 	struct ad714x_chip *ad714x;
974 	void *drv_mem;
975 	unsigned long irqflags;
976 
977 	struct ad714x_button_drv *bt_drv;
978 	struct ad714x_slider_drv *sd_drv;
979 	struct ad714x_wheel_drv *wl_drv;
980 	struct ad714x_touchpad_drv *tp_drv;
981 
982 
983 	if (irq <= 0) {
984 		dev_err(dev, "IRQ not configured!\n");
985 		error = -EINVAL;
986 		goto err_out;
987 	}
988 
989 	if (dev->platform_data == NULL) {
990 		dev_err(dev, "platform data for ad714x doesn't exist\n");
991 		error = -EINVAL;
992 		goto err_out;
993 	}
994 
995 	ad714x = kzalloc(sizeof(*ad714x) + sizeof(*ad714x->sw) +
996 			 sizeof(*sd_drv) * plat_data->slider_num +
997 			 sizeof(*wl_drv) * plat_data->wheel_num +
998 			 sizeof(*tp_drv) * plat_data->touchpad_num +
999 			 sizeof(*bt_drv) * plat_data->button_num, GFP_KERNEL);
1000 	if (!ad714x) {
1001 		error = -ENOMEM;
1002 		goto err_out;
1003 	}
1004 
1005 	ad714x->hw = plat_data;
1006 
1007 	drv_mem = ad714x + 1;
1008 	ad714x->sw = drv_mem;
1009 	drv_mem += sizeof(*ad714x->sw);
1010 	ad714x->sw->slider = sd_drv = drv_mem;
1011 	drv_mem += sizeof(*sd_drv) * ad714x->hw->slider_num;
1012 	ad714x->sw->wheel = wl_drv = drv_mem;
1013 	drv_mem += sizeof(*wl_drv) * ad714x->hw->wheel_num;
1014 	ad714x->sw->touchpad = tp_drv = drv_mem;
1015 	drv_mem += sizeof(*tp_drv) * ad714x->hw->touchpad_num;
1016 	ad714x->sw->button = bt_drv = drv_mem;
1017 	drv_mem += sizeof(*bt_drv) * ad714x->hw->button_num;
1018 
1019 	ad714x->read = read;
1020 	ad714x->write = write;
1021 	ad714x->irq = irq;
1022 	ad714x->dev = dev;
1023 
1024 	error = ad714x_hw_detect(ad714x);
1025 	if (error)
1026 		goto err_free_mem;
1027 
1028 	/* initialize and request sw/hw resources */
1029 
1030 	ad714x_hw_init(ad714x);
1031 	mutex_init(&ad714x->mutex);
1032 
1033 	/*
1034 	 * Allocate and register AD714X input device
1035 	 */
1036 	alloc_idx = 0;
1037 
1038 	/* a slider uses one input_dev instance */
1039 	if (ad714x->hw->slider_num > 0) {
1040 		struct ad714x_slider_plat *sd_plat = ad714x->hw->slider;
1041 
1042 		for (i = 0; i < ad714x->hw->slider_num; i++) {
1043 			sd_drv[i].input = input[alloc_idx] = input_allocate_device();
1044 			if (!input[alloc_idx]) {
1045 				error = -ENOMEM;
1046 				goto err_free_dev;
1047 			}
1048 
1049 			__set_bit(EV_ABS, input[alloc_idx]->evbit);
1050 			__set_bit(EV_KEY, input[alloc_idx]->evbit);
1051 			__set_bit(ABS_X, input[alloc_idx]->absbit);
1052 			__set_bit(BTN_TOUCH, input[alloc_idx]->keybit);
1053 			input_set_abs_params(input[alloc_idx],
1054 				ABS_X, 0, sd_plat->max_coord, 0, 0);
1055 
1056 			input[alloc_idx]->id.bustype = bus_type;
1057 			input[alloc_idx]->id.product = ad714x->product;
1058 			input[alloc_idx]->id.version = ad714x->version;
1059 			input[alloc_idx]->name = "ad714x_captouch_slider";
1060 			input[alloc_idx]->dev.parent = dev;
1061 
1062 			error = input_register_device(input[alloc_idx]);
1063 			if (error)
1064 				goto err_free_dev;
1065 
1066 			alloc_idx++;
1067 		}
1068 	}
1069 
1070 	/* a wheel uses one input_dev instance */
1071 	if (ad714x->hw->wheel_num > 0) {
1072 		struct ad714x_wheel_plat *wl_plat = ad714x->hw->wheel;
1073 
1074 		for (i = 0; i < ad714x->hw->wheel_num; i++) {
1075 			wl_drv[i].input = input[alloc_idx] = input_allocate_device();
1076 			if (!input[alloc_idx]) {
1077 				error = -ENOMEM;
1078 				goto err_free_dev;
1079 			}
1080 
1081 			__set_bit(EV_KEY, input[alloc_idx]->evbit);
1082 			__set_bit(EV_ABS, input[alloc_idx]->evbit);
1083 			__set_bit(ABS_WHEEL, input[alloc_idx]->absbit);
1084 			__set_bit(BTN_TOUCH, input[alloc_idx]->keybit);
1085 			input_set_abs_params(input[alloc_idx],
1086 				ABS_WHEEL, 0, wl_plat->max_coord, 0, 0);
1087 
1088 			input[alloc_idx]->id.bustype = bus_type;
1089 			input[alloc_idx]->id.product = ad714x->product;
1090 			input[alloc_idx]->id.version = ad714x->version;
1091 			input[alloc_idx]->name = "ad714x_captouch_wheel";
1092 			input[alloc_idx]->dev.parent = dev;
1093 
1094 			error = input_register_device(input[alloc_idx]);
1095 			if (error)
1096 				goto err_free_dev;
1097 
1098 			alloc_idx++;
1099 		}
1100 	}
1101 
1102 	/* a touchpad uses one input_dev instance */
1103 	if (ad714x->hw->touchpad_num > 0) {
1104 		struct ad714x_touchpad_plat *tp_plat = ad714x->hw->touchpad;
1105 
1106 		for (i = 0; i < ad714x->hw->touchpad_num; i++) {
1107 			tp_drv[i].input = input[alloc_idx] = input_allocate_device();
1108 			if (!input[alloc_idx]) {
1109 				error = -ENOMEM;
1110 				goto err_free_dev;
1111 			}
1112 
1113 			__set_bit(EV_ABS, input[alloc_idx]->evbit);
1114 			__set_bit(EV_KEY, input[alloc_idx]->evbit);
1115 			__set_bit(ABS_X, input[alloc_idx]->absbit);
1116 			__set_bit(ABS_Y, input[alloc_idx]->absbit);
1117 			__set_bit(BTN_TOUCH, input[alloc_idx]->keybit);
1118 			input_set_abs_params(input[alloc_idx],
1119 				ABS_X, 0, tp_plat->x_max_coord, 0, 0);
1120 			input_set_abs_params(input[alloc_idx],
1121 				ABS_Y, 0, tp_plat->y_max_coord, 0, 0);
1122 
1123 			input[alloc_idx]->id.bustype = bus_type;
1124 			input[alloc_idx]->id.product = ad714x->product;
1125 			input[alloc_idx]->id.version = ad714x->version;
1126 			input[alloc_idx]->name = "ad714x_captouch_pad";
1127 			input[alloc_idx]->dev.parent = dev;
1128 
1129 			error = input_register_device(input[alloc_idx]);
1130 			if (error)
1131 				goto err_free_dev;
1132 
1133 			alloc_idx++;
1134 		}
1135 	}
1136 
1137 	/* all buttons use one input node */
1138 	if (ad714x->hw->button_num > 0) {
1139 		struct ad714x_button_plat *bt_plat = ad714x->hw->button;
1140 
1141 		input[alloc_idx] = input_allocate_device();
1142 		if (!input[alloc_idx]) {
1143 			error = -ENOMEM;
1144 			goto err_free_dev;
1145 		}
1146 
1147 		__set_bit(EV_KEY, input[alloc_idx]->evbit);
1148 		for (i = 0; i < ad714x->hw->button_num; i++) {
1149 			bt_drv[i].input = input[alloc_idx];
1150 			__set_bit(bt_plat[i].keycode, input[alloc_idx]->keybit);
1151 		}
1152 
1153 		input[alloc_idx]->id.bustype = bus_type;
1154 		input[alloc_idx]->id.product = ad714x->product;
1155 		input[alloc_idx]->id.version = ad714x->version;
1156 		input[alloc_idx]->name = "ad714x_captouch_button";
1157 		input[alloc_idx]->dev.parent = dev;
1158 
1159 		error = input_register_device(input[alloc_idx]);
1160 		if (error)
1161 			goto err_free_dev;
1162 
1163 		alloc_idx++;
1164 	}
1165 
1166 	irqflags = plat_data->irqflags ?: IRQF_TRIGGER_FALLING;
1167 	irqflags |= IRQF_ONESHOT;
1168 
1169 	error = request_threaded_irq(ad714x->irq, NULL, ad714x_interrupt_thread,
1170 				     irqflags, "ad714x_captouch", ad714x);
1171 	if (error) {
1172 		dev_err(dev, "can't allocate irq %d\n", ad714x->irq);
1173 		goto err_unreg_dev;
1174 	}
1175 
1176 	return ad714x;
1177 
1178  err_free_dev:
1179 	dev_err(dev, "failed to setup AD714x input device %i\n", alloc_idx);
1180 	input_free_device(input[alloc_idx]);
1181  err_unreg_dev:
1182 	while (--alloc_idx >= 0)
1183 		input_unregister_device(input[alloc_idx]);
1184  err_free_mem:
1185 	kfree(ad714x);
1186  err_out:
1187 	return ERR_PTR(error);
1188 }
1189 EXPORT_SYMBOL(ad714x_probe);
1190 
1191 void ad714x_remove(struct ad714x_chip *ad714x)
1192 {
1193 	struct ad714x_platform_data *hw = ad714x->hw;
1194 	struct ad714x_driver_data *sw = ad714x->sw;
1195 	int i;
1196 
1197 	free_irq(ad714x->irq, ad714x);
1198 
1199 	/* unregister and free all input devices */
1200 
1201 	for (i = 0; i < hw->slider_num; i++)
1202 		input_unregister_device(sw->slider[i].input);
1203 
1204 	for (i = 0; i < hw->wheel_num; i++)
1205 		input_unregister_device(sw->wheel[i].input);
1206 
1207 	for (i = 0; i < hw->touchpad_num; i++)
1208 		input_unregister_device(sw->touchpad[i].input);
1209 
1210 	if (hw->button_num)
1211 		input_unregister_device(sw->button[0].input);
1212 
1213 	kfree(ad714x);
1214 }
1215 EXPORT_SYMBOL(ad714x_remove);
1216 
1217 #ifdef CONFIG_PM
1218 int ad714x_disable(struct ad714x_chip *ad714x)
1219 {
1220 	unsigned short data;
1221 
1222 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1223 
1224 	mutex_lock(&ad714x->mutex);
1225 
1226 	data = ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL] | 0x3;
1227 	ad714x->write(ad714x, AD714X_PWR_CTRL, data);
1228 
1229 	mutex_unlock(&ad714x->mutex);
1230 
1231 	return 0;
1232 }
1233 EXPORT_SYMBOL(ad714x_disable);
1234 
1235 int ad714x_enable(struct ad714x_chip *ad714x)
1236 {
1237 	dev_dbg(ad714x->dev, "%s enter\n", __func__);
1238 
1239 	mutex_lock(&ad714x->mutex);
1240 
1241 	/* resume to non-shutdown mode */
1242 
1243 	ad714x->write(ad714x, AD714X_PWR_CTRL,
1244 			ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL]);
1245 
1246 	/* make sure the interrupt output line is not low level after resume,
1247 	 * otherwise we will get no chance to enter falling-edge irq again
1248 	 */
1249 
1250 	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state, 3);
1251 
1252 	mutex_unlock(&ad714x->mutex);
1253 
1254 	return 0;
1255 }
1256 EXPORT_SYMBOL(ad714x_enable);
1257 #endif
1258 
1259 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor Driver");
1260 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
1261 MODULE_LICENSE("GPL");
1262