1 /*
2  * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
3  *
4  * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
5  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
6  * Parts Copyright : Ian Molton <spyro@f2s.com>
7  *                   Andrew Zabolotny <zap@homelink.ru>
8  *                   Russell King <rmk@arm.linux.org.uk>
9  *
10  *  This program is free software; you can redistribute  it and/or modify it
11  *  under  the terms of  the GNU General  Public License as published by the
12  *  Free Software Foundation;  either version 2 of the  License, or (at your
13  *  option) any later version.
14  *
15  */
16 
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/kernel.h>
20 #include <linux/input.h>
21 #include <linux/delay.h>
22 #include <linux/bitops.h>
23 #include <linux/wm97xx.h>
24 
25 #define TS_NAME			"wm97xx"
26 #define WM9713_VERSION		"1.00"
27 #define DEFAULT_PRESSURE	0xb0c0
28 
29 /*
30  * Module parameters
31  */
32 
33 /*
34  * Set internal pull up for pen detect.
35  *
36  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
37  * i.e. pull up resistance = 64k Ohms / rpu.
38  *
39  * Adjust this value if you are having problems with pen detect not
40  * detecting any down event.
41  */
42 static int rpu = 8;
43 module_param(rpu, int, 0);
44 MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");
45 
46 /*
47  * Set current used for pressure measurement.
48  *
49  * Set pil = 2 to use 400uA
50  *     pil = 1 to use 200uA and
51  *     pil = 0 to disable pressure measurement.
52  *
53  * This is used to increase the range of values returned by the adc
54  * when measureing touchpanel pressure.
55  */
56 static int pil;
57 module_param(pil, int, 0);
58 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
59 
60 /*
61  * Set threshold for pressure measurement.
62  *
63  * Pen down pressure below threshold is ignored.
64  */
65 static int pressure = DEFAULT_PRESSURE & 0xfff;
66 module_param(pressure, int, 0);
67 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
68 
69 /*
70  * Set adc sample delay.
71  *
72  * For accurate touchpanel measurements, some settling time may be
73  * required between the switch matrix applying a voltage across the
74  * touchpanel plate and the ADC sampling the signal.
75  *
76  * This delay can be set by setting delay = n, where n is the array
77  * position of the delay in the array delay_table below.
78  * Long delays > 1ms are supported for completeness, but are not
79  * recommended.
80  */
81 static int delay = 4;
82 module_param(delay, int, 0);
83 MODULE_PARM_DESC(delay, "Set adc sample delay.");
84 
85 /*
86  * Set five_wire = 1 to use a 5 wire touchscreen.
87  *
88  * NOTE: Five wire mode does not allow for readback of pressure.
89  */
90 static int five_wire;
91 module_param(five_wire, int, 0);
92 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
93 
94 /*
95  * Set adc mask function.
96  *
97  * Sources of glitch noise, such as signals driving an LCD display, may feed
98  * through to the touch screen plates and affect measurement accuracy. In
99  * order to minimise this, a signal may be applied to the MASK pin to delay or
100  * synchronise the sampling.
101  *
102  * 0 = No delay or sync
103  * 1 = High on pin stops conversions
104  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
105  * 3 = Edge triggered, edge on pin starts conversion after delay param
106  */
107 static int mask;
108 module_param(mask, int, 0);
109 MODULE_PARM_DESC(mask, "Set adc mask function.");
110 
111 /*
112  * Coordinate Polling Enable.
113  *
114  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
115  * for every poll.
116  */
117 static int coord;
118 module_param(coord, int, 0);
119 MODULE_PARM_DESC(coord, "Polling coordinate mode");
120 
121 /*
122  * ADC sample delay times in uS
123  */
124 static const int delay_table[] = {
125 	21,    /* 1 AC97 Link frames */
126 	42,    /* 2 */
127 	84,    /* 4 */
128 	167,   /* 8 */
129 	333,   /* 16 */
130 	667,   /* 32 */
131 	1000,  /* 48 */
132 	1333,  /* 64 */
133 	2000,  /* 96 */
134 	2667,  /* 128 */
135 	3333,  /* 160 */
136 	4000,  /* 192 */
137 	4667,  /* 224 */
138 	5333,  /* 256 */
139 	6000,  /* 288 */
140 	0      /* No delay, switch matrix always on */
141 };
142 
143 /*
144  * Delay after issuing a POLL command.
145  *
146  * The delay is 3 AC97 link frames + the touchpanel settling delay
147  */
148 static inline void poll_delay(int d)
149 {
150 	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
151 }
152 
153 /*
154  * set up the physical settings of the WM9713
155  */
156 static void wm9713_phy_init(struct wm97xx *wm)
157 {
158 	u16 dig1 = 0, dig2, dig3;
159 
160 	/* default values */
161 	dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
162 	dig3 = WM9712_RPU(1);
163 
164 	/* rpu */
165 	if (rpu) {
166 		dig3 &= 0xffc0;
167 		dig3 |= WM9712_RPU(rpu);
168 		dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
169 			 64000 / rpu);
170 	}
171 
172 	/* Five wire panel? */
173 	if (five_wire) {
174 		dig3 |= WM9713_45W;
175 		dev_info(wm->dev, "setting 5-wire touchscreen mode.");
176 
177 		if (pil) {
178 			dev_warn(wm->dev,
179 				 "Pressure measurement not supported in 5 "
180 				 "wire mode, disabling\n");
181 			pil = 0;
182 		}
183 	}
184 
185 	/* touchpanel pressure */
186 	if (pil == 2) {
187 		dig3 |= WM9712_PIL;
188 		dev_info(wm->dev,
189 			 "setting pressure measurement current to 400uA.");
190 	} else if (pil)
191 		dev_info(wm->dev,
192 			 "setting pressure measurement current to 200uA.");
193 	if (!pil)
194 		pressure = 0;
195 
196 	/* sample settling delay */
197 	if (delay < 0 || delay > 15) {
198 		dev_info(wm->dev, "supplied delay out of range.");
199 		delay = 4;
200 		dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
201 			 delay_table[delay]);
202 	}
203 	dig2 &= 0xff0f;
204 	dig2 |= WM97XX_DELAY(delay);
205 
206 	/* mask */
207 	dig3 |= ((mask & 0x3) << 4);
208 	if (coord)
209 		dig3 |= WM9713_WAIT;
210 
211 	wm->misc = wm97xx_reg_read(wm, 0x5a);
212 
213 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
214 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
215 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
216 	wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
217 }
218 
219 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
220 {
221 	u16 val;
222 
223 	if (enable) {
224 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
225 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
226 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
227 				 WM97XX_PRP_DET_DIG);
228 		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
229 	} else {
230 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
231 					~WM97XX_PRP_DET_DIG);
232 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
233 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
234 	}
235 }
236 
237 static void wm9713_dig_restore(struct wm97xx *wm)
238 {
239 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
240 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
241 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
242 }
243 
244 static void wm9713_aux_prepare(struct wm97xx *wm)
245 {
246 	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
247 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
248 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
249 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
250 }
251 
252 static inline int is_pden(struct wm97xx *wm)
253 {
254 	return wm->dig[2] & WM9713_PDEN;
255 }
256 
257 /*
258  * Read a sample from the WM9713 adc in polling mode.
259  */
260 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
261 {
262 	u16 dig1;
263 	int timeout = 5 * delay;
264 
265 	if (!wm->pen_probably_down) {
266 		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
267 		if (!(data & WM97XX_PEN_DOWN))
268 			return RC_PENUP;
269 		wm->pen_probably_down = 1;
270 	}
271 
272 	/* set up digitiser */
273 	if (adcsel & 0x8000)
274 		adcsel = 1 << ((adcsel & 0x7fff) + 3);
275 
276 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
277 	dig1 &= ~WM9713_ADCSEL_MASK;
278 
279 	if (wm->mach_ops && wm->mach_ops->pre_sample)
280 		wm->mach_ops->pre_sample(adcsel);
281 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | adcsel | WM9713_POLL);
282 
283 	/* wait 3 AC97 time slots + delay for conversion */
284 	poll_delay(delay);
285 
286 	/* wait for POLL to go low */
287 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
288 		timeout) {
289 		udelay(AC97_LINK_FRAME);
290 		timeout--;
291 	}
292 
293 	if (timeout <= 0) {
294 		/* If PDEN is set, we can get a timeout when pen goes up */
295 		if (is_pden(wm))
296 			wm->pen_probably_down = 0;
297 		else
298 			dev_dbg(wm->dev, "adc sample timeout");
299 		return RC_PENUP;
300 	}
301 
302 	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
303 	if (wm->mach_ops && wm->mach_ops->post_sample)
304 		wm->mach_ops->post_sample(adcsel);
305 
306 	/* check we have correct sample */
307 	if ((*sample & WM97XX_ADCSRC_MASK) != ffs(adcsel >> 1) << 12) {
308 		dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
309 			*sample & WM97XX_ADCSRC_MASK);
310 		return RC_PENUP;
311 	}
312 
313 	if (!(*sample & WM97XX_PEN_DOWN)) {
314 		wm->pen_probably_down = 0;
315 		return RC_PENUP;
316 	}
317 
318 	return RC_VALID;
319 }
320 
321 /*
322  * Read a coordinate from the WM9713 adc in polling mode.
323  */
324 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
325 {
326 	u16 dig1;
327 	int timeout = 5 * delay;
328 
329 	if (!wm->pen_probably_down) {
330 		u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
331 		if (!(val & WM97XX_PEN_DOWN))
332 			return RC_PENUP;
333 		wm->pen_probably_down = 1;
334 	}
335 
336 	/* set up digitiser */
337 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
338 	dig1 &= ~WM9713_ADCSEL_MASK;
339 	if (pil)
340 		dig1 |= WM9713_ADCSEL_PRES;
341 
342 	if (wm->mach_ops && wm->mach_ops->pre_sample)
343 		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
344 	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
345 			 dig1 | WM9713_POLL | WM9713_COO);
346 
347 	/* wait 3 AC97 time slots + delay for conversion */
348 	poll_delay(delay);
349 	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
350 	/* wait for POLL to go low */
351 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
352 	       && timeout) {
353 		udelay(AC97_LINK_FRAME);
354 		timeout--;
355 	}
356 
357 	if (timeout <= 0) {
358 		/* If PDEN is set, we can get a timeout when pen goes up */
359 		if (is_pden(wm))
360 			wm->pen_probably_down = 0;
361 		else
362 			dev_dbg(wm->dev, "adc sample timeout");
363 		return RC_PENUP;
364 	}
365 
366 	/* read back data */
367 	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
368 	if (pil)
369 		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
370 	else
371 		data->p = DEFAULT_PRESSURE;
372 
373 	if (wm->mach_ops && wm->mach_ops->post_sample)
374 		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
375 
376 	/* check we have correct sample */
377 	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
378 		goto err;
379 	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
380 		goto err;
381 
382 	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
383 		wm->pen_probably_down = 0;
384 		return RC_PENUP;
385 	}
386 	return RC_VALID;
387 err:
388 	return 0;
389 }
390 
391 /*
392  * Sample the WM9713 touchscreen in polling mode
393  */
394 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
395 {
396 	int rc;
397 
398 	if (coord) {
399 		rc = wm9713_poll_coord(wm, data);
400 		if (rc != RC_VALID)
401 			return rc;
402 	} else {
403 		rc = wm9713_poll_sample(wm, WM9713_ADCSEL_X, &data->x);
404 		if (rc != RC_VALID)
405 			return rc;
406 		rc = wm9713_poll_sample(wm, WM9713_ADCSEL_Y, &data->y);
407 		if (rc != RC_VALID)
408 			return rc;
409 		if (pil) {
410 			rc = wm9713_poll_sample(wm, WM9713_ADCSEL_PRES,
411 						&data->p);
412 			if (rc != RC_VALID)
413 				return rc;
414 		} else
415 			data->p = DEFAULT_PRESSURE;
416 	}
417 	return RC_VALID;
418 }
419 
420 /*
421  * Enable WM9713 continuous mode, i.e. touch data is streamed across
422  * an AC97 slot
423  */
424 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
425 {
426 	u16 dig1, dig2, dig3;
427 	int ret = 0;
428 
429 	dig1 = wm->dig[0];
430 	dig2 = wm->dig[1];
431 	dig3 = wm->dig[2];
432 
433 	if (enable) {
434 		/* continous mode */
435 		if (wm->mach_ops->acc_startup &&
436 			(ret = wm->mach_ops->acc_startup(wm)) < 0)
437 			return ret;
438 
439 		dig1 &= ~WM9713_ADCSEL_MASK;
440 		dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
441 			WM9713_ADCSEL_Y;
442 		if (pil)
443 			dig1 |= WM9713_ADCSEL_PRES;
444 		dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
445 			WM97XX_CM_RATE_MASK);
446 		dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
447 		WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
448 		dig3 |= WM9713_PDEN;
449 	} else {
450 		dig1 &= ~(WM9713_CTC | WM9713_COO);
451 		dig2 &= ~WM97XX_SLEN;
452 		dig3 &= ~WM9713_PDEN;
453 		if (wm->mach_ops->acc_shutdown)
454 			wm->mach_ops->acc_shutdown(wm);
455 	}
456 
457 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
458 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
459 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
460 
461 	return ret;
462 }
463 
464 struct wm97xx_codec_drv wm9713_codec = {
465 	.id = WM9713_ID2,
466 	.name = "wm9713",
467 	.poll_sample = wm9713_poll_sample,
468 	.poll_touch = wm9713_poll_touch,
469 	.acc_enable = wm9713_acc_enable,
470 	.phy_init = wm9713_phy_init,
471 	.dig_enable = wm9713_dig_enable,
472 	.dig_restore = wm9713_dig_restore,
473 	.aux_prepare = wm9713_aux_prepare,
474 };
475 EXPORT_SYMBOL_GPL(wm9713_codec);
476 
477 /* Module information */
478 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
479 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
480 MODULE_LICENSE("GPL");
481