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 <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 WM9712_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 = 3;
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 WM9712
155 */
156static void wm9712_phy_init(struct wm97xx *wm)
157{
158	u16 dig1 = 0;
159	u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
160
161	/* WM9712 rpu */
162	if (rpu) {
163		dig2 &= 0xffc0;
164		dig2 |= WM9712_RPU(rpu);
165		dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms\n",
166			64000 / rpu);
167	}
168
169	/* WM9712 five wire */
170	if (five_wire) {
171		dig2 |= WM9712_45W;
172		dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n");
173
174		if (pil) {
175			dev_warn(wm->dev, "pressure measurement is not "
176				 "supported in 5-wire mode\n");
177			pil = 0;
178		}
179	}
180
181	/* touchpanel pressure current*/
182	if (pil == 2) {
183		dig2 |= WM9712_PIL;
184		dev_dbg(wm->dev,
185			"setting pressure measurement current to 400uA.\n");
186	} else if (pil)
187		dev_dbg(wm->dev,
188			"setting pressure measurement current to 200uA.\n");
189	if (!pil)
190		pressure = 0;
191
192	/* polling mode sample settling delay */
193	if (delay < 0 || delay > 15) {
194		dev_dbg(wm->dev, "supplied delay out of range.\n");
195		delay = 4;
196	}
197	dig1 &= 0xff0f;
198	dig1 |= WM97XX_DELAY(delay);
199	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n",
200		delay_table[delay]);
201
202	/* mask */
203	dig2 |= ((mask & 0x3) << 6);
204	if (mask) {
205		u16 reg;
206		/* Set GPIO4 as Mask Pin*/
207		reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
208		wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
209		reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
210		wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
211	}
212
213	/* wait - coord mode */
214	if (coord)
215		dig2 |= WM9712_WAIT;
216
217	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
218	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
219}
220
221static void wm9712_dig_enable(struct wm97xx *wm, int enable)
222{
223	u16 dig2 = wm->dig[2];
224
225	if (enable) {
226		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
227				 dig2 | WM97XX_PRP_DET_DIG);
228		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
229	} else
230		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
231				 dig2 & ~WM97XX_PRP_DET_DIG);
232}
233
234static void wm9712_aux_prepare(struct wm97xx *wm)
235{
236	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
237	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
238	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
239}
240
241static void wm9712_dig_restore(struct wm97xx *wm)
242{
243	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
244	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
245}
246
247static inline int is_pden(struct wm97xx *wm)
248{
249	return wm->dig[2] & WM9712_PDEN;
250}
251
252/*
253 * Read a sample from the WM9712 adc in polling mode.
254 */
255static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
256{
257	int timeout = 5 * delay;
258	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
259
260	if (wants_pen && !wm->pen_probably_down) {
261		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
262		if (!(data & WM97XX_PEN_DOWN))
263			return RC_PENUP;
264		wm->pen_probably_down = 1;
265	}
266
267	/* set up digitiser */
268	if (wm->mach_ops && wm->mach_ops->pre_sample)
269		wm->mach_ops->pre_sample(adcsel);
270	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
271				| WM97XX_POLL | WM97XX_DELAY(delay));
272
273	/* wait 3 AC97 time slots + delay for conversion */
274	poll_delay(delay);
275
276	/* wait for POLL to go low */
277	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
278	       && timeout) {
279		udelay(AC97_LINK_FRAME);
280		timeout--;
281	}
282
283	if (timeout <= 0) {
284		/* If PDEN is set, we can get a timeout when pen goes up */
285		if (is_pden(wm))
286			wm->pen_probably_down = 0;
287		else
288			dev_dbg(wm->dev, "adc sample timeout\n");
289		return RC_PENUP;
290	}
291
292	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
293	if (wm->mach_ops && wm->mach_ops->post_sample)
294		wm->mach_ops->post_sample(adcsel);
295
296	/* check we have correct sample */
297	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
298		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x\n",
299			adcsel & WM97XX_ADCSEL_MASK,
300			*sample & WM97XX_ADCSEL_MASK);
301		return RC_AGAIN;
302	}
303
304	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
305		/* Sometimes it reads a wrong value the first time. */
306		*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
307		if (!(*sample & WM97XX_PEN_DOWN)) {
308			wm->pen_probably_down = 0;
309			return RC_PENUP;
310		}
311	}
312
313	return RC_VALID;
314}
315
316/*
317 * Read a coord from the WM9712 adc in polling mode.
318 */
319static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
320{
321	int timeout = 5 * delay;
322
323	if (!wm->pen_probably_down) {
324		u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
325		if (!(data_rd & WM97XX_PEN_DOWN))
326			return RC_PENUP;
327		wm->pen_probably_down = 1;
328	}
329
330	/* set up digitiser */
331	if (wm->mach_ops && wm->mach_ops->pre_sample)
332		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
333
334	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
335		WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
336
337	/* wait 3 AC97 time slots + delay for conversion and read x */
338	poll_delay(delay);
339	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
340	/* wait for POLL to go low */
341	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
342	       && timeout) {
343		udelay(AC97_LINK_FRAME);
344		timeout--;
345	}
346
347	if (timeout <= 0) {
348		/* If PDEN is set, we can get a timeout when pen goes up */
349		if (is_pden(wm))
350			wm->pen_probably_down = 0;
351		else
352			dev_dbg(wm->dev, "adc sample timeout\n");
353		return RC_PENUP;
354	}
355
356	/* read back y data */
357	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
358	if (pil)
359		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
360	else
361		data->p = DEFAULT_PRESSURE;
362
363	if (wm->mach_ops && wm->mach_ops->post_sample)
364		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
365
366	/* check we have correct sample */
367	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
368		goto err;
369	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
370		goto err;
371
372	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
373		wm->pen_probably_down = 0;
374		return RC_PENUP;
375	}
376	return RC_VALID;
377err:
378	return 0;
379}
380
381/*
382 * Sample the WM9712 touchscreen in polling mode
383 */
384static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
385{
386	int rc;
387
388	if (coord) {
389		rc = wm9712_poll_coord(wm, data);
390		if (rc != RC_VALID)
391			return rc;
392	} else {
393		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN,
394					&data->x);
395		if (rc != RC_VALID)
396			return rc;
397
398		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN,
399					&data->y);
400		if (rc != RC_VALID)
401			return rc;
402
403		if (pil && !five_wire) {
404			rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
405						&data->p);
406			if (rc != RC_VALID)
407				return rc;
408		} else
409			data->p = DEFAULT_PRESSURE;
410	}
411	return RC_VALID;
412}
413
414/*
415 * Enable WM9712 continuous mode, i.e. touch data is streamed across
416 * an AC97 slot
417 */
418static int wm9712_acc_enable(struct wm97xx *wm, int enable)
419{
420	u16 dig1, dig2;
421	int ret = 0;
422
423	dig1 = wm->dig[1];
424	dig2 = wm->dig[2];
425
426	if (enable) {
427		/* continuous mode */
428		if (wm->mach_ops->acc_startup) {
429			ret = wm->mach_ops->acc_startup(wm);
430			if (ret < 0)
431				return ret;
432		}
433		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
434			WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
435		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
436			WM97XX_DELAY(delay) |
437			WM97XX_SLT(wm->acc_slot) |
438			WM97XX_RATE(wm->acc_rate);
439		if (pil)
440			dig1 |= WM97XX_ADCSEL_PRES;
441		dig2 |= WM9712_PDEN;
442	} else {
443		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
444		dig2 &= ~WM9712_PDEN;
445		if (wm->mach_ops->acc_shutdown)
446			wm->mach_ops->acc_shutdown(wm);
447	}
448
449	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
450	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
451
452	return 0;
453}
454
455struct wm97xx_codec_drv wm9712_codec = {
456	.id = WM9712_ID2,
457	.name = "wm9712",
458	.poll_sample = wm9712_poll_sample,
459	.poll_touch = wm9712_poll_touch,
460	.acc_enable = wm9712_acc_enable,
461	.phy_init = wm9712_phy_init,
462	.dig_enable = wm9712_dig_enable,
463	.dig_restore = wm9712_dig_restore,
464	.aux_prepare = wm9712_aux_prepare,
465};
466EXPORT_SYMBOL_GPL(wm9712_codec);
467
468/* Module information */
469MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
470MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
471MODULE_LICENSE("GPL");
472