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 */
42static int rpu = 8;
43module_param(rpu, int, 0);
44MODULE_PARM_DESC(rpu, "Set internal pull up resistor 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 */
56static int pil;
57module_param(pil, int, 0);
58MODULE_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 */
65static int pressure = DEFAULT_PRESSURE & 0xfff;
66module_param(pressure, int, 0);
67MODULE_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 */
81static int delay = 4;
82module_param(delay, int, 0);
83MODULE_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 */
90static int five_wire;
91module_param(five_wire, int, 0);
92MODULE_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 */
107static int mask;
108module_param(mask, int, 0);
109MODULE_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 */
117static int coord;
118module_param(coord, int, 0);
119MODULE_PARM_DESC(coord, "Polling coordinate mode");
120
121/*
122 * ADC sample delay times in uS
123 */
124static 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 */
148static 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 */
156static 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
219static 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
237static 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
244static 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
252static 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 */
260static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
261{
262	u16 dig1;
263	int timeout = 5 * delay;
264	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
265
266	if (wants_pen && !wm->pen_probably_down) {
267		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
268		if (!(data & WM97XX_PEN_DOWN))
269			return RC_PENUP;
270		wm->pen_probably_down = 1;
271	}
272
273	/* set up digitiser */
274	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
275	dig1 &= ~WM9713_ADCSEL_MASK;
276	/* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
277	dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
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 | 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 ^ adcsel) & WM97XX_ADCSEL_MASK) {
308		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
309			adcsel & WM97XX_ADCSEL_MASK,
310			*sample & WM97XX_ADCSEL_MASK);
311		return RC_PENUP;
312	}
313
314	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
315		wm->pen_probably_down = 0;
316		return RC_PENUP;
317	}
318
319	return RC_VALID;
320}
321
322/*
323 * Read a coordinate from the WM9713 adc in polling mode.
324 */
325static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
326{
327	u16 dig1;
328	int timeout = 5 * delay;
329
330	if (!wm->pen_probably_down) {
331		u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
332		if (!(val & WM97XX_PEN_DOWN))
333			return RC_PENUP;
334		wm->pen_probably_down = 1;
335	}
336
337	/* set up digitiser */
338	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
339	dig1 &= ~WM9713_ADCSEL_MASK;
340	if (pil)
341		dig1 |= WM9713_ADCSEL_PRES;
342
343	if (wm->mach_ops && wm->mach_ops->pre_sample)
344		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
345	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
346			 dig1 | WM9713_POLL | WM9713_COO);
347
348	/* wait 3 AC97 time slots + delay for conversion */
349	poll_delay(delay);
350	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
351	/* wait for POLL to go low */
352	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
353	       && timeout) {
354		udelay(AC97_LINK_FRAME);
355		timeout--;
356	}
357
358	if (timeout <= 0) {
359		/* If PDEN is set, we can get a timeout when pen goes up */
360		if (is_pden(wm))
361			wm->pen_probably_down = 0;
362		else
363			dev_dbg(wm->dev, "adc sample timeout");
364		return RC_PENUP;
365	}
366
367	/* read back data */
368	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
369	if (pil)
370		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
371	else
372		data->p = DEFAULT_PRESSURE;
373
374	if (wm->mach_ops && wm->mach_ops->post_sample)
375		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
376
377	/* check we have correct sample */
378	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
379		goto err;
380	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
381		goto err;
382
383	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
384		wm->pen_probably_down = 0;
385		return RC_PENUP;
386	}
387	return RC_VALID;
388err:
389	return 0;
390}
391
392/*
393 * Sample the WM9713 touchscreen in polling mode
394 */
395static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
396{
397	int rc;
398
399	if (coord) {
400		rc = wm9713_poll_coord(wm, data);
401		if (rc != RC_VALID)
402			return rc;
403	} else {
404		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
405		if (rc != RC_VALID)
406			return rc;
407		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
408		if (rc != RC_VALID)
409			return rc;
410		if (pil) {
411			rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
412						&data->p);
413			if (rc != RC_VALID)
414				return rc;
415		} else
416			data->p = DEFAULT_PRESSURE;
417	}
418	return RC_VALID;
419}
420
421/*
422 * Enable WM9713 continuous mode, i.e. touch data is streamed across
423 * an AC97 slot
424 */
425static int wm9713_acc_enable(struct wm97xx *wm, int enable)
426{
427	u16 dig1, dig2, dig3;
428	int ret = 0;
429
430	dig1 = wm->dig[0];
431	dig2 = wm->dig[1];
432	dig3 = wm->dig[2];
433
434	if (enable) {
435		/* continuous mode */
436		if (wm->mach_ops->acc_startup &&
437			(ret = wm->mach_ops->acc_startup(wm)) < 0)
438			return ret;
439
440		dig1 &= ~WM9713_ADCSEL_MASK;
441		dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
442			WM9713_ADCSEL_Y;
443		if (pil)
444			dig1 |= WM9713_ADCSEL_PRES;
445		dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
446			WM97XX_CM_RATE_MASK);
447		dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
448		WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
449		dig3 |= WM9713_PDEN;
450	} else {
451		dig1 &= ~(WM9713_CTC | WM9713_COO);
452		dig2 &= ~WM97XX_SLEN;
453		dig3 &= ~WM9713_PDEN;
454		if (wm->mach_ops->acc_shutdown)
455			wm->mach_ops->acc_shutdown(wm);
456	}
457
458	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
459	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
460	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
461
462	return ret;
463}
464
465struct wm97xx_codec_drv wm9713_codec = {
466	.id = WM9713_ID2,
467	.name = "wm9713",
468	.poll_sample = wm9713_poll_sample,
469	.poll_touch = wm9713_poll_touch,
470	.acc_enable = wm9713_acc_enable,
471	.phy_init = wm9713_phy_init,
472	.dig_enable = wm9713_dig_enable,
473	.dig_restore = wm9713_dig_restore,
474	.aux_prepare = wm9713_aux_prepare,
475};
476EXPORT_SYMBOL_GPL(wm9713_codec);
477
478/* Module information */
479MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
480MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
481MODULE_LICENSE("GPL");
482