summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/wm9705.c
blob: 372efbc694ffbf7ebe71e96decefd71060e6d7c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
/*
 * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
 *
 * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
 * Author: Liam Girdwood
 *         liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
 * Parts Copyright : Ian Molton <spyro@f2s.com>
 *                   Andrew Zabolotny <zap@homelink.ru>
 *                   Russell King <rmk@arm.linux.org.uk>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/wm97xx.h>

#define TS_NAME			"wm97xx"
#define WM9705_VERSION		"1.00"
#define DEFAULT_PRESSURE	0xb0c0

/*
 * Module parameters
 */

/*
 * Set current used for pressure measurement.
 *
 * Set pil = 2 to use 400uA
 *     pil = 1 to use 200uA and
 *     pil = 0 to disable pressure measurement.
 *
 * This is used to increase the range of values returned by the adc
 * when measureing touchpanel pressure.
 */
static int pil;
module_param(pil, int, 0);
MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");

/*
 * Set threshold for pressure measurement.
 *
 * Pen down pressure below threshold is ignored.
 */
static int pressure = DEFAULT_PRESSURE & 0xfff;
module_param(pressure, int, 0);
MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");

/*
 * Set adc sample delay.
 *
 * For accurate touchpanel measurements, some settling time may be
 * required between the switch matrix applying a voltage across the
 * touchpanel plate and the ADC sampling the signal.
 *
 * This delay can be set by setting delay = n, where n is the array
 * position of the delay in the array delay_table below.
 * Long delays > 1ms are supported for completeness, but are not
 * recommended.
 */
static int delay = 4;
module_param(delay, int, 0);
MODULE_PARM_DESC(delay, "Set adc sample delay.");

/*
 * Pen detect comparator threshold.
 *
 * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
 * i.e. 1 =  Vmid/15 threshold
 *      15 =  Vmid/1 threshold
 *
 * Adjust this value if you are having problems with pen detect not
 * detecting any down events.
 */
static int pdd = 8;
module_param(pdd, int, 0);
MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");

/*
 * Set adc mask function.
 *
 * Sources of glitch noise, such as signals driving an LCD display, may feed
 * through to the touch screen plates and affect measurement accuracy. In
 * order to minimise this, a signal may be applied to the MASK pin to delay or
 * synchronise the sampling.
 *
 * 0 = No delay or sync
 * 1 = High on pin stops conversions
 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 * 3 = Edge triggered, edge on pin starts conversion after delay param
 */
static int mask;
module_param(mask, int, 0);
MODULE_PARM_DESC(mask, "Set adc mask function.");

/*
 * ADC sample delay times in uS
 */
static const int delay_table[] = {
	21,    /* 1 AC97 Link frames */
	42,    /* 2                  */
	84,    /* 4                  */
	167,   /* 8                  */
	333,   /* 16                 */
	667,   /* 32                 */
	1000,  /* 48                 */
	1333,  /* 64                 */
	2000,  /* 96                 */
	2667,  /* 128                */
	3333,  /* 160                */
	4000,  /* 192                */
	4667,  /* 224                */
	5333,  /* 256                */
	6000,  /* 288                */
	0      /* No delay, switch matrix always on */
};

/*
 * Delay after issuing a POLL command.
 *
 * The delay is 3 AC97 link frames + the touchpanel settling delay
 */
static inline void poll_delay(int d)
{
	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
}

/*
 * set up the physical settings of the WM9705
 */
static void wm9705_phy_init(struct wm97xx *wm)
{
	u16 dig1 = 0, dig2 = WM97XX_RPR;

	/*
	* mute VIDEO and AUX as they share X and Y touchscreen
	* inputs on the WM9705
	*/
	wm97xx_reg_write(wm, AC97_AUX, 0x8000);
	wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);

	/* touchpanel pressure current*/
	if (pil == 2) {
		dig2 |= WM9705_PIL;
		dev_dbg(wm->dev,
			"setting pressure measurement current to 400uA.");
	} else if (pil)
		dev_dbg(wm->dev,
			"setting pressure measurement current to 200uA.");
	if (!pil)
		pressure = 0;

	/* polling mode sample settling delay */
	if (delay != 4) {
		if (delay < 0 || delay > 15) {
			dev_dbg(wm->dev, "supplied delay out of range.");
			delay = 4;
		}
	}
	dig1 &= 0xff0f;
	dig1 |= WM97XX_DELAY(delay);
	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
		delay_table[delay]);

	/* WM9705 pdd */
	dig2 |= (pdd & 0x000f);
	dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));

	/* mask */
	dig2 |= ((mask & 0x3) << 4);

	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
}

static void wm9705_dig_enable(struct wm97xx *wm, int enable)
{
	if (enable) {
		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
				 wm->dig[2] | WM97XX_PRP_DET_DIG);
		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
	} else
		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
				 wm->dig[2] & ~WM97XX_PRP_DET_DIG);
}

static void wm9705_aux_prepare(struct wm97xx *wm)
{
	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
}

static void wm9705_dig_restore(struct wm97xx *wm)
{
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
}

static inline int is_pden(struct wm97xx *wm)
{
	return wm->dig[2] & WM9705_PDEN;
}

/*
 * Read a sample from the WM9705 adc in polling mode.
 */
static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
{
	int timeout = 5 * delay;

	if (!wm->pen_probably_down) {
		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
		if (!(data & WM97XX_PEN_DOWN))
			return RC_PENUP;
		wm->pen_probably_down = 1;
	}

	/* set up digitiser */
	if (adcsel & 0x8000)
		adcsel = ((adcsel & 0x7fff) + 3) << 12;

	if (wm->mach_ops && wm->mach_ops->pre_sample)
		wm->mach_ops->pre_sample(adcsel);
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
			 adcsel | WM97XX_POLL | WM97XX_DELAY(delay));

	/* wait 3 AC97 time slots + delay for conversion */
	poll_delay(delay);

	/* wait for POLL to go low */
	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
	       && timeout) {
		udelay(AC97_LINK_FRAME);
		timeout--;
	}

	if (timeout == 0) {
		/* If PDEN is set, we can get a timeout when pen goes up */
		if (is_pden(wm))
			wm->pen_probably_down = 0;
		else
			dev_dbg(wm->dev, "adc sample timeout");
		return RC_PENUP;
	}

	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	if (wm->mach_ops && wm->mach_ops->post_sample)
		wm->mach_ops->post_sample(adcsel);

	/* check we have correct sample */
	if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) {
		dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
		*sample & WM97XX_ADCSEL_MASK);
		return RC_PENUP;
	}

	if (!(*sample & WM97XX_PEN_DOWN)) {
		wm->pen_probably_down = 0;
		return RC_PENUP;
	}

	return RC_VALID;
}

/*
 * Sample the WM9705 touchscreen in polling mode
 */
static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
{
	int rc;

	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
	if (rc != RC_VALID)
		return rc;
	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
	if (rc != RC_VALID)
		return rc;
	if (pil) {
		rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES, &data->p);
		if (rc != RC_VALID)
			return rc;
	} else
		data->p = DEFAULT_PRESSURE;

	return RC_VALID;
}

/*
 * Enable WM9705 continuous mode, i.e. touch data is streamed across
 * an AC97 slot
 */
static int wm9705_acc_enable(struct wm97xx *wm, int enable)
{
	u16 dig1, dig2;
	int ret = 0;

	dig1 = wm->dig[1];
	dig2 = wm->dig[2];

	if (enable) {
		/* continous mode */
		if (wm->mach_ops->acc_startup &&
		    (ret = wm->mach_ops->acc_startup(wm)) < 0)
			return ret;
		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
			  WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
			WM97XX_DELAY(delay) |
			WM97XX_SLT(wm->acc_slot) |
			WM97XX_RATE(wm->acc_rate);
		if (pil)
			dig1 |= WM97XX_ADCSEL_PRES;
		dig2 |= WM9705_PDEN;
	} else {
		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
		dig2 &= ~WM9705_PDEN;
		if (wm->mach_ops->acc_shutdown)
			wm->mach_ops->acc_shutdown(wm);
	}

	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);

	return ret;
}

struct wm97xx_codec_drv wm9705_codec = {
	.id = WM9705_ID2,
	.name = "wm9705",
	.poll_sample = wm9705_poll_sample,
	.poll_touch = wm9705_poll_touch,
	.acc_enable = wm9705_acc_enable,
	.phy_init = wm9705_phy_init,
	.dig_enable = wm9705_dig_enable,
	.dig_restore = wm9705_dig_restore,
	.aux_prepare = wm9705_aux_prepare,
};
EXPORT_SYMBOL_GPL(wm9705_codec);

/* Module information */
MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
MODULE_LICENSE("GPL");