1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
4  *
5  * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
6  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
7  * Parts Copyright : Ian Molton <spyro@f2s.com>
8  *                   Andrew Zabolotny <zap@homelink.ru>
9  *                   Russell King <rmk@arm.linux.org.uk>
10  */
11 
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/kernel.h>
15 #include <linux/input.h>
16 #include <linux/delay.h>
17 #include <linux/bitops.h>
18 #include <linux/wm97xx.h>
19 
20 #define TS_NAME			"wm97xx"
21 #define WM9713_VERSION		"1.00"
22 #define DEFAULT_PRESSURE	0xb0c0
23 
24 /*
25  * Module parameters
26  */
27 
28 /*
29  * Set internal pull up for pen detect.
30  *
31  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
32  * i.e. pull up resistance = 64k Ohms / rpu.
33  *
34  * Adjust this value if you are having problems with pen detect not
35  * detecting any down event.
36  */
37 static int rpu = 8;
38 module_param(rpu, int, 0);
39 MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect.");
40 
41 /*
42  * Set current used for pressure measurement.
43  *
44  * Set pil = 2 to use 400uA
45  *     pil = 1 to use 200uA and
46  *     pil = 0 to disable pressure measurement.
47  *
48  * This is used to increase the range of values returned by the adc
49  * when measureing touchpanel pressure.
50  */
51 static int pil;
52 module_param(pil, int, 0);
53 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
54 
55 /*
56  * Set threshold for pressure measurement.
57  *
58  * Pen down pressure below threshold is ignored.
59  */
60 static int pressure = DEFAULT_PRESSURE & 0xfff;
61 module_param(pressure, int, 0);
62 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
63 
64 /*
65  * Set adc sample delay.
66  *
67  * For accurate touchpanel measurements, some settling time may be
68  * required between the switch matrix applying a voltage across the
69  * touchpanel plate and the ADC sampling the signal.
70  *
71  * This delay can be set by setting delay = n, where n is the array
72  * position of the delay in the array delay_table below.
73  * Long delays > 1ms are supported for completeness, but are not
74  * recommended.
75  */
76 static int delay = 4;
77 module_param(delay, int, 0);
78 MODULE_PARM_DESC(delay, "Set adc sample delay.");
79 
80 /*
81  * Set five_wire = 1 to use a 5 wire touchscreen.
82  *
83  * NOTE: Five wire mode does not allow for readback of pressure.
84  */
85 static int five_wire;
86 module_param(five_wire, int, 0);
87 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
88 
89 /*
90  * Set adc mask function.
91  *
92  * Sources of glitch noise, such as signals driving an LCD display, may feed
93  * through to the touch screen plates and affect measurement accuracy. In
94  * order to minimise this, a signal may be applied to the MASK pin to delay or
95  * synchronise the sampling.
96  *
97  * 0 = No delay or sync
98  * 1 = High on pin stops conversions
99  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
100  * 3 = Edge triggered, edge on pin starts conversion after delay param
101  */
102 static int mask;
103 module_param(mask, int, 0);
104 MODULE_PARM_DESC(mask, "Set adc mask function.");
105 
106 /*
107  * Coordinate Polling Enable.
108  *
109  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
110  * for every poll.
111  */
112 static int coord;
113 module_param(coord, int, 0);
114 MODULE_PARM_DESC(coord, "Polling coordinate mode");
115 
116 /*
117  * ADC sample delay times in uS
118  */
119 static const int delay_table[] = {
120 	21,    /* 1 AC97 Link frames */
121 	42,    /* 2 */
122 	84,    /* 4 */
123 	167,   /* 8 */
124 	333,   /* 16 */
125 	667,   /* 32 */
126 	1000,  /* 48 */
127 	1333,  /* 64 */
128 	2000,  /* 96 */
129 	2667,  /* 128 */
130 	3333,  /* 160 */
131 	4000,  /* 192 */
132 	4667,  /* 224 */
133 	5333,  /* 256 */
134 	6000,  /* 288 */
135 	0      /* No delay, switch matrix always on */
136 };
137 
138 /*
139  * Delay after issuing a POLL command.
140  *
141  * The delay is 3 AC97 link frames + the touchpanel settling delay
142  */
143 static inline void poll_delay(int d)
144 {
145 	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
146 }
147 
148 /*
149  * set up the physical settings of the WM9713
150  */
151 static void wm9713_phy_init(struct wm97xx *wm)
152 {
153 	u16 dig1 = 0, dig2, dig3;
154 
155 	/* default values */
156 	dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
157 	dig3 = WM9712_RPU(1);
158 
159 	/* rpu */
160 	if (rpu) {
161 		dig3 &= 0xffc0;
162 		dig3 |= WM9712_RPU(rpu);
163 		dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
164 			 64000 / rpu);
165 	}
166 
167 	/* Five wire panel? */
168 	if (five_wire) {
169 		dig3 |= WM9713_45W;
170 		dev_info(wm->dev, "setting 5-wire touchscreen mode.");
171 
172 		if (pil) {
173 			dev_warn(wm->dev,
174 				 "Pressure measurement not supported in 5 "
175 				 "wire mode, disabling\n");
176 			pil = 0;
177 		}
178 	}
179 
180 	/* touchpanel pressure */
181 	if (pil == 2) {
182 		dig3 |= WM9712_PIL;
183 		dev_info(wm->dev,
184 			 "setting pressure measurement current to 400uA.");
185 	} else if (pil)
186 		dev_info(wm->dev,
187 			 "setting pressure measurement current to 200uA.");
188 	if (!pil)
189 		pressure = 0;
190 
191 	/* sample settling delay */
192 	if (delay < 0 || delay > 15) {
193 		dev_info(wm->dev, "supplied delay out of range.");
194 		delay = 4;
195 		dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
196 			 delay_table[delay]);
197 	}
198 	dig2 &= 0xff0f;
199 	dig2 |= WM97XX_DELAY(delay);
200 
201 	/* mask */
202 	dig3 |= ((mask & 0x3) << 4);
203 	if (coord)
204 		dig3 |= WM9713_WAIT;
205 
206 	wm->misc = wm97xx_reg_read(wm, 0x5a);
207 
208 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
209 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
210 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
211 	wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
212 }
213 
214 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
215 {
216 	u16 val;
217 
218 	if (enable) {
219 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
220 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
221 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
222 				 WM97XX_PRP_DET_DIG);
223 		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
224 	} else {
225 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
226 					~WM97XX_PRP_DET_DIG);
227 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
228 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
229 	}
230 }
231 
232 static void wm9713_dig_restore(struct wm97xx *wm)
233 {
234 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
235 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
236 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
237 }
238 
239 static void wm9713_aux_prepare(struct wm97xx *wm)
240 {
241 	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
242 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
243 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
244 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
245 }
246 
247 static inline int is_pden(struct wm97xx *wm)
248 {
249 	return wm->dig[2] & WM9713_PDEN;
250 }
251 
252 /*
253  * Read a sample from the WM9713 adc in polling mode.
254  */
255 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
256 {
257 	u16 dig1;
258 	int timeout = 5 * delay;
259 	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
260 
261 	if (wants_pen && !wm->pen_probably_down) {
262 		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
263 		if (!(data & WM97XX_PEN_DOWN))
264 			return RC_PENUP;
265 		wm->pen_probably_down = 1;
266 	}
267 
268 	/* set up digitiser */
269 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
270 	dig1 &= ~WM9713_ADCSEL_MASK;
271 	/* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
272 	dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
273 
274 	if (wm->mach_ops && wm->mach_ops->pre_sample)
275 		wm->mach_ops->pre_sample(adcsel);
276 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | WM9713_POLL);
277 
278 	/* wait 3 AC97 time slots + delay for conversion */
279 	poll_delay(delay);
280 
281 	/* wait for POLL to go low */
282 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
283 		timeout) {
284 		udelay(AC97_LINK_FRAME);
285 		timeout--;
286 	}
287 
288 	if (timeout <= 0) {
289 		/* If PDEN is set, we can get a timeout when pen goes up */
290 		if (is_pden(wm))
291 			wm->pen_probably_down = 0;
292 		else
293 			dev_dbg(wm->dev, "adc sample timeout");
294 		return RC_PENUP;
295 	}
296 
297 	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
298 	if (wm->mach_ops && wm->mach_ops->post_sample)
299 		wm->mach_ops->post_sample(adcsel);
300 
301 	/* check we have correct sample */
302 	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
303 		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
304 			adcsel & WM97XX_ADCSEL_MASK,
305 			*sample & WM97XX_ADCSEL_MASK);
306 		return RC_PENUP;
307 	}
308 
309 	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
310 		wm->pen_probably_down = 0;
311 		return RC_PENUP;
312 	}
313 
314 	return RC_VALID;
315 }
316 
317 /*
318  * Read a coordinate from the WM9713 adc in polling mode.
319  */
320 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
321 {
322 	u16 dig1;
323 	int timeout = 5 * delay;
324 
325 	if (!wm->pen_probably_down) {
326 		u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
327 		if (!(val & WM97XX_PEN_DOWN))
328 			return RC_PENUP;
329 		wm->pen_probably_down = 1;
330 	}
331 
332 	/* set up digitiser */
333 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
334 	dig1 &= ~WM9713_ADCSEL_MASK;
335 	if (pil)
336 		dig1 |= WM9713_ADCSEL_PRES;
337 
338 	if (wm->mach_ops && wm->mach_ops->pre_sample)
339 		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
340 	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
341 			 dig1 | WM9713_POLL | WM9713_COO);
342 
343 	/* wait 3 AC97 time slots + delay for conversion */
344 	poll_delay(delay);
345 	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
346 	/* wait for POLL to go low */
347 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
348 	       && timeout) {
349 		udelay(AC97_LINK_FRAME);
350 		timeout--;
351 	}
352 
353 	if (timeout <= 0) {
354 		/* If PDEN is set, we can get a timeout when pen goes up */
355 		if (is_pden(wm))
356 			wm->pen_probably_down = 0;
357 		else
358 			dev_dbg(wm->dev, "adc sample timeout");
359 		return RC_PENUP;
360 	}
361 
362 	/* read back data */
363 	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
364 	if (pil)
365 		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
366 	else
367 		data->p = DEFAULT_PRESSURE;
368 
369 	if (wm->mach_ops && wm->mach_ops->post_sample)
370 		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
371 
372 	/* check we have correct sample */
373 	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
374 		goto err;
375 	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
376 		goto err;
377 
378 	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
379 		wm->pen_probably_down = 0;
380 		return RC_PENUP;
381 	}
382 	return RC_VALID;
383 err:
384 	return 0;
385 }
386 
387 /*
388  * Sample the WM9713 touchscreen in polling mode
389  */
390 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
391 {
392 	int rc;
393 
394 	if (coord) {
395 		rc = wm9713_poll_coord(wm, data);
396 		if (rc != RC_VALID)
397 			return rc;
398 	} else {
399 		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
400 		if (rc != RC_VALID)
401 			return rc;
402 		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
403 		if (rc != RC_VALID)
404 			return rc;
405 		if (pil) {
406 			rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
407 						&data->p);
408 			if (rc != RC_VALID)
409 				return rc;
410 		} else
411 			data->p = DEFAULT_PRESSURE;
412 	}
413 	return RC_VALID;
414 }
415 
416 /*
417  * Enable WM9713 continuous mode, i.e. touch data is streamed across
418  * an AC97 slot
419  */
420 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
421 {
422 	u16 dig1, dig2, dig3;
423 	int ret = 0;
424 
425 	dig1 = wm->dig[0];
426 	dig2 = wm->dig[1];
427 	dig3 = wm->dig[2];
428 
429 	if (enable) {
430 		/* continuous mode */
431 		if (wm->mach_ops->acc_startup &&
432 			(ret = wm->mach_ops->acc_startup(wm)) < 0)
433 			return ret;
434 
435 		dig1 &= ~WM9713_ADCSEL_MASK;
436 		dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
437 			WM9713_ADCSEL_Y;
438 		if (pil)
439 			dig1 |= WM9713_ADCSEL_PRES;
440 		dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
441 			WM97XX_CM_RATE_MASK);
442 		dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
443 		WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
444 		dig3 |= WM9713_PDEN;
445 	} else {
446 		dig1 &= ~(WM9713_CTC | WM9713_COO);
447 		dig2 &= ~WM97XX_SLEN;
448 		dig3 &= ~WM9713_PDEN;
449 		if (wm->mach_ops->acc_shutdown)
450 			wm->mach_ops->acc_shutdown(wm);
451 	}
452 
453 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
454 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
455 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
456 
457 	return ret;
458 }
459 
460 struct wm97xx_codec_drv wm9713_codec = {
461 	.id = WM9713_ID2,
462 	.name = "wm9713",
463 	.poll_sample = wm9713_poll_sample,
464 	.poll_touch = wm9713_poll_touch,
465 	.acc_enable = wm9713_acc_enable,
466 	.phy_init = wm9713_phy_init,
467 	.dig_enable = wm9713_dig_enable,
468 	.dig_restore = wm9713_dig_restore,
469 	.aux_prepare = wm9713_aux_prepare,
470 };
471 EXPORT_SYMBOL_GPL(wm9713_codec);
472 
473 /* Module information */
474 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
475 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
476 MODULE_LICENSE("GPL");
477