1 /*
2  * wm9712.c  --  Codec driver for Wolfson WM9712 AC97 Codecs.
3  *
4  * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
5  * Author: Liam Girdwood
6  *         liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
7  * Parts Copyright : Ian Molton <spyro@f2s.com>
8  *                   Andrew Zabolotny <zap@homelink.ru>
9  *                   Russell King <rmk@arm.linux.org.uk>
10  *
11  *  This program is free software; you can redistribute  it and/or modify it
12  *  under  the terms of  the GNU General  Public License as published by the
13  *  Free Software Foundation;  either version 2 of the  License, or (at your
14  *  option) any later version.
15  *
16  */
17 
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/version.h>
21 #include <linux/kernel.h>
22 #include <linux/input.h>
23 #include <linux/delay.h>
24 #include <linux/bitops.h>
25 #include <linux/wm97xx.h>
26 
27 #define TS_NAME			"wm97xx"
28 #define WM9712_VERSION		"1.00"
29 #define DEFAULT_PRESSURE	0xb0c0
30 
31 /*
32  * Module parameters
33  */
34 
35 /*
36  * Set internal pull up for pen detect.
37  *
38  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
39  * i.e. pull up resistance = 64k Ohms / rpu.
40  *
41  * Adjust this value if you are having problems with pen detect not
42  * detecting any down event.
43  */
44 static int rpu = 8;
45 module_param(rpu, int, 0);
46 MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");
47 
48 /*
49  * Set current used for pressure measurement.
50  *
51  * Set pil = 2 to use 400uA
52  *     pil = 1 to use 200uA and
53  *     pil = 0 to disable pressure measurement.
54  *
55  * This is used to increase the range of values returned by the adc
56  * when measureing touchpanel pressure.
57  */
58 static int pil;
59 module_param(pil, int, 0);
60 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
61 
62 /*
63  * Set threshold for pressure measurement.
64  *
65  * Pen down pressure below threshold is ignored.
66  */
67 static int pressure = DEFAULT_PRESSURE & 0xfff;
68 module_param(pressure, int, 0);
69 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
70 
71 /*
72  * Set adc sample delay.
73  *
74  * For accurate touchpanel measurements, some settling time may be
75  * required between the switch matrix applying a voltage across the
76  * touchpanel plate and the ADC sampling the signal.
77  *
78  * This delay can be set by setting delay = n, where n is the array
79  * position of the delay in the array delay_table below.
80  * Long delays > 1ms are supported for completeness, but are not
81  * recommended.
82  */
83 static int delay = 3;
84 module_param(delay, int, 0);
85 MODULE_PARM_DESC(delay, "Set adc sample delay.");
86 
87 /*
88  * Set five_wire = 1 to use a 5 wire touchscreen.
89  *
90  * NOTE: Five wire mode does not allow for readback of pressure.
91  */
92 static int five_wire;
93 module_param(five_wire, int, 0);
94 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
95 
96 /*
97  * Set adc mask function.
98  *
99  * Sources of glitch noise, such as signals driving an LCD display, may feed
100  * through to the touch screen plates and affect measurement accuracy. In
101  * order to minimise this, a signal may be applied to the MASK pin to delay or
102  * synchronise the sampling.
103  *
104  * 0 = No delay or sync
105  * 1 = High on pin stops conversions
106  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
107  * 3 = Edge triggered, edge on pin starts conversion after delay param
108  */
109 static int mask;
110 module_param(mask, int, 0);
111 MODULE_PARM_DESC(mask, "Set adc mask function.");
112 
113 /*
114  * Coordinate Polling Enable.
115  *
116  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
117  * for every poll.
118  */
119 static int coord;
120 module_param(coord, int, 0);
121 MODULE_PARM_DESC(coord, "Polling coordinate mode");
122 
123 /*
124  * ADC sample delay times in uS
125  */
126 static const int delay_table[] = {
127 	21,    /* 1 AC97 Link frames */
128 	42,    /* 2 */
129 	84,    /* 4 */
130 	167,   /* 8 */
131 	333,   /* 16 */
132 	667,   /* 32 */
133 	1000,  /* 48 */
134 	1333,  /* 64 */
135 	2000,  /* 96 */
136 	2667,  /* 128 */
137 	3333,  /* 160 */
138 	4000,  /* 192 */
139 	4667,  /* 224 */
140 	5333,  /* 256 */
141 	6000,  /* 288 */
142 	0      /* No delay, switch matrix always on */
143 };
144 
145 /*
146  * Delay after issuing a POLL command.
147  *
148  * The delay is 3 AC97 link frames + the touchpanel settling delay
149  */
150 static inline void poll_delay(int d)
151 {
152 	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
153 }
154 
155 /*
156  * set up the physical settings of the WM9712
157  */
158 static void wm9712_phy_init(struct wm97xx *wm)
159 {
160 	u16 dig1 = 0;
161 	u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
162 
163 	/* WM9712 rpu */
164 	if (rpu) {
165 		dig2 &= 0xffc0;
166 		dig2 |= WM9712_RPU(rpu);
167 		dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms",
168 			64000 / rpu);
169 	}
170 
171 	/* touchpanel pressure current*/
172 	if (pil == 2) {
173 		dig2 |= WM9712_PIL;
174 		dev_dbg(wm->dev,
175 			"setting pressure measurement current to 400uA.");
176 	} else if (pil)
177 		dev_dbg(wm->dev,
178 			"setting pressure measurement current to 200uA.");
179 	if (!pil)
180 		pressure = 0;
181 
182 	/* WM9712 five wire */
183 	if (five_wire) {
184 		dig2 |= WM9712_45W;
185 		dev_dbg(wm->dev, "setting 5-wire touchscreen mode.");
186 	}
187 
188 	/* polling mode sample settling delay */
189 	if (delay < 0 || delay > 15) {
190 		dev_dbg(wm->dev, "supplied delay out of range.");
191 		delay = 4;
192 	}
193 	dig1 &= 0xff0f;
194 	dig1 |= WM97XX_DELAY(delay);
195 	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
196 		delay_table[delay]);
197 
198 	/* mask */
199 	dig2 |= ((mask & 0x3) << 6);
200 	if (mask) {
201 		u16 reg;
202 		/* Set GPIO4 as Mask Pin*/
203 		reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
204 		wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
205 		reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
206 		wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
207 	}
208 
209 	/* wait - coord mode */
210 	if (coord)
211 		dig2 |= WM9712_WAIT;
212 
213 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
214 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
215 }
216 
217 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
218 {
219 	u16 dig2 = wm->dig[2];
220 
221 	if (enable) {
222 		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
223 				 dig2 | WM97XX_PRP_DET_DIG);
224 		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
225 	} else
226 		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
227 				 dig2 & ~WM97XX_PRP_DET_DIG);
228 }
229 
230 static void wm9712_aux_prepare(struct wm97xx *wm)
231 {
232 	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
233 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
234 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
235 }
236 
237 static void wm9712_dig_restore(struct wm97xx *wm)
238 {
239 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
240 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
241 }
242 
243 static inline int is_pden(struct wm97xx *wm)
244 {
245 	return wm->dig[2] & WM9712_PDEN;
246 }
247 
248 /*
249  * Read a sample from the WM9712 adc in polling mode.
250  */
251 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
252 {
253 	int timeout = 5 * delay;
254 
255 	if (!wm->pen_probably_down) {
256 		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
257 		if (!(data & WM97XX_PEN_DOWN))
258 			return RC_PENUP;
259 		wm->pen_probably_down = 1;
260 	}
261 
262 	/* set up digitiser */
263 	if (adcsel & 0x8000)
264 		adcsel = ((adcsel & 0x7fff) + 3) << 12;
265 
266 	if (wm->mach_ops && wm->mach_ops->pre_sample)
267 		wm->mach_ops->pre_sample(adcsel);
268 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
269 			 adcsel | WM97XX_POLL | WM97XX_DELAY(delay));
270 
271 	/* wait 3 AC97 time slots + delay for conversion */
272 	poll_delay(delay);
273 
274 	/* wait for POLL to go low */
275 	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
276 	       && timeout) {
277 		udelay(AC97_LINK_FRAME);
278 		timeout--;
279 	}
280 
281 	if (timeout <= 0) {
282 		/* If PDEN is set, we can get a timeout when pen goes up */
283 		if (is_pden(wm))
284 			wm->pen_probably_down = 0;
285 		else
286 			dev_dbg(wm->dev, "adc sample timeout");
287 		return RC_PENUP;
288 	}
289 
290 	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
291 	if (wm->mach_ops && wm->mach_ops->post_sample)
292 		wm->mach_ops->post_sample(adcsel);
293 
294 	/* check we have correct sample */
295 	if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) {
296 		dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
297 		*sample & WM97XX_ADCSEL_MASK);
298 		return RC_PENUP;
299 	}
300 
301 	if (!(*sample & WM97XX_PEN_DOWN)) {
302 		wm->pen_probably_down = 0;
303 		return RC_PENUP;
304 	}
305 
306 	return RC_VALID;
307 }
308 
309 /*
310  * Read a coord from the WM9712 adc in polling mode.
311  */
312 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
313 {
314 	int timeout = 5 * delay;
315 
316 	if (!wm->pen_probably_down) {
317 		u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
318 		if (!(data_rd & WM97XX_PEN_DOWN))
319 			return RC_PENUP;
320 		wm->pen_probably_down = 1;
321 	}
322 
323 	/* set up digitiser */
324 	if (wm->mach_ops && wm->mach_ops->pre_sample)
325 		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
326 
327 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
328 		WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
329 
330 	/* wait 3 AC97 time slots + delay for conversion and read x */
331 	poll_delay(delay);
332 	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
333 	/* wait for POLL to go low */
334 	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
335 	       && timeout) {
336 		udelay(AC97_LINK_FRAME);
337 		timeout--;
338 	}
339 
340 	if (timeout <= 0) {
341 		/* If PDEN is set, we can get a timeout when pen goes up */
342 		if (is_pden(wm))
343 			wm->pen_probably_down = 0;
344 		else
345 			dev_dbg(wm->dev, "adc sample timeout");
346 		return RC_PENUP;
347 	}
348 
349 	/* read back y data */
350 	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
351 	if (pil)
352 		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
353 	else
354 		data->p = DEFAULT_PRESSURE;
355 
356 	if (wm->mach_ops && wm->mach_ops->post_sample)
357 		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
358 
359 	/* check we have correct sample */
360 	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
361 		goto err;
362 	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
363 		goto err;
364 
365 	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
366 		wm->pen_probably_down = 0;
367 		return RC_PENUP;
368 	}
369 	return RC_VALID;
370 err:
371 	return 0;
372 }
373 
374 /*
375  * Sample the WM9712 touchscreen in polling mode
376  */
377 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
378 {
379 	int rc;
380 
381 	if (coord) {
382 		rc = wm9712_poll_coord(wm, data);
383 		if (rc != RC_VALID)
384 			return rc;
385 	} else {
386 		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
387 		if (rc != RC_VALID)
388 			return rc;
389 
390 		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
391 		if (rc != RC_VALID)
392 			return rc;
393 
394 		if (pil && !five_wire) {
395 			rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES,
396 						&data->p);
397 			if (rc != RC_VALID)
398 				return rc;
399 		} else
400 			data->p = DEFAULT_PRESSURE;
401 	}
402 	return RC_VALID;
403 }
404 
405 /*
406  * Enable WM9712 continuous mode, i.e. touch data is streamed across
407  * an AC97 slot
408  */
409 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
410 {
411 	u16 dig1, dig2;
412 	int ret = 0;
413 
414 	dig1 = wm->dig[1];
415 	dig2 = wm->dig[2];
416 
417 	if (enable) {
418 		/* continous mode */
419 		if (wm->mach_ops->acc_startup) {
420 			ret = wm->mach_ops->acc_startup(wm);
421 			if (ret < 0)
422 				return ret;
423 		}
424 		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
425 			WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
426 		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
427 			WM97XX_DELAY(delay) |
428 			WM97XX_SLT(wm->acc_slot) |
429 			WM97XX_RATE(wm->acc_rate);
430 		if (pil)
431 			dig1 |= WM97XX_ADCSEL_PRES;
432 		dig2 |= WM9712_PDEN;
433 	} else {
434 		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
435 		dig2 &= ~WM9712_PDEN;
436 		if (wm->mach_ops->acc_shutdown)
437 			wm->mach_ops->acc_shutdown(wm);
438 	}
439 
440 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
441 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
442 
443 	return 0;
444 }
445 
446 struct wm97xx_codec_drv wm9712_codec = {
447 	.id = WM9712_ID2,
448 	.name = "wm9712",
449 	.poll_sample = wm9712_poll_sample,
450 	.poll_touch = wm9712_poll_touch,
451 	.acc_enable = wm9712_acc_enable,
452 	.phy_init = wm9712_phy_init,
453 	.dig_enable = wm9712_dig_enable,
454 	.dig_restore = wm9712_dig_restore,
455 	.aux_prepare = wm9712_aux_prepare,
456 };
457 EXPORT_SYMBOL_GPL(wm9712_codec);
458 
459 /* Module information */
460 MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
461 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
462 MODULE_LICENSE("GPL");
463