1/*
2 * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
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 WM9705_VERSION		"1.00"
27#define DEFAULT_PRESSURE	0xb0c0
28
29/*
30 * Module parameters
31 */
32
33/*
34 * Set current used for pressure measurement.
35 *
36 * Set pil = 2 to use 400uA
37 *     pil = 1 to use 200uA and
38 *     pil = 0 to disable pressure measurement.
39 *
40 * This is used to increase the range of values returned by the adc
41 * when measureing touchpanel pressure.
42 */
43static int pil;
44module_param(pil, int, 0);
45MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
46
47/*
48 * Set threshold for pressure measurement.
49 *
50 * Pen down pressure below threshold is ignored.
51 */
52static int pressure = DEFAULT_PRESSURE & 0xfff;
53module_param(pressure, int, 0);
54MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
55
56/*
57 * Set adc sample delay.
58 *
59 * For accurate touchpanel measurements, some settling time may be
60 * required between the switch matrix applying a voltage across the
61 * touchpanel plate and the ADC sampling the signal.
62 *
63 * This delay can be set by setting delay = n, where n is the array
64 * position of the delay in the array delay_table below.
65 * Long delays > 1ms are supported for completeness, but are not
66 * recommended.
67 */
68static int delay = 4;
69module_param(delay, int, 0);
70MODULE_PARM_DESC(delay, "Set adc sample delay.");
71
72/*
73 * Pen detect comparator threshold.
74 *
75 * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
76 * i.e. 1 =  Vmid/15 threshold
77 *      15 =  Vmid/1 threshold
78 *
79 * Adjust this value if you are having problems with pen detect not
80 * detecting any down events.
81 */
82static int pdd = 8;
83module_param(pdd, int, 0);
84MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
85
86/*
87 * Set adc mask function.
88 *
89 * Sources of glitch noise, such as signals driving an LCD display, may feed
90 * through to the touch screen plates and affect measurement accuracy. In
91 * order to minimise this, a signal may be applied to the MASK pin to delay or
92 * synchronise the sampling.
93 *
94 * 0 = No delay or sync
95 * 1 = High on pin stops conversions
96 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
97 * 3 = Edge triggered, edge on pin starts conversion after delay param
98 */
99static int mask;
100module_param(mask, int, 0);
101MODULE_PARM_DESC(mask, "Set adc mask function.");
102
103/*
104 * ADC sample delay times in uS
105 */
106static const int delay_table[] = {
107	21,    /* 1 AC97 Link frames */
108	42,    /* 2                  */
109	84,    /* 4                  */
110	167,   /* 8                  */
111	333,   /* 16                 */
112	667,   /* 32                 */
113	1000,  /* 48                 */
114	1333,  /* 64                 */
115	2000,  /* 96                 */
116	2667,  /* 128                */
117	3333,  /* 160                */
118	4000,  /* 192                */
119	4667,  /* 224                */
120	5333,  /* 256                */
121	6000,  /* 288                */
122	0      /* No delay, switch matrix always on */
123};
124
125/*
126 * Delay after issuing a POLL command.
127 *
128 * The delay is 3 AC97 link frames + the touchpanel settling delay
129 */
130static inline void poll_delay(int d)
131{
132	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
133}
134
135/*
136 * set up the physical settings of the WM9705
137 */
138static void wm9705_phy_init(struct wm97xx *wm)
139{
140	u16 dig1 = 0, dig2 = WM97XX_RPR;
141
142	/*
143	* mute VIDEO and AUX as they share X and Y touchscreen
144	* inputs on the WM9705
145	*/
146	wm97xx_reg_write(wm, AC97_AUX, 0x8000);
147	wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
148
149	/* touchpanel pressure current*/
150	if (pil == 2) {
151		dig2 |= WM9705_PIL;
152		dev_dbg(wm->dev,
153			"setting pressure measurement current to 400uA.");
154	} else if (pil)
155		dev_dbg(wm->dev,
156			"setting pressure measurement current to 200uA.");
157	if (!pil)
158		pressure = 0;
159
160	/* polling mode sample settling delay */
161	if (delay != 4) {
162		if (delay < 0 || delay > 15) {
163			dev_dbg(wm->dev, "supplied delay out of range.");
164			delay = 4;
165		}
166	}
167	dig1 &= 0xff0f;
168	dig1 |= WM97XX_DELAY(delay);
169	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
170		delay_table[delay]);
171
172	/* WM9705 pdd */
173	dig2 |= (pdd & 0x000f);
174	dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
175
176	/* mask */
177	dig2 |= ((mask & 0x3) << 4);
178
179	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
180	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
181}
182
183static void wm9705_dig_enable(struct wm97xx *wm, int enable)
184{
185	if (enable) {
186		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
187				 wm->dig[2] | WM97XX_PRP_DET_DIG);
188		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
189	} else
190		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
191				 wm->dig[2] & ~WM97XX_PRP_DET_DIG);
192}
193
194static void wm9705_aux_prepare(struct wm97xx *wm)
195{
196	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
197	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
198	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
199}
200
201static void wm9705_dig_restore(struct wm97xx *wm)
202{
203	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
204	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
205}
206
207static inline int is_pden(struct wm97xx *wm)
208{
209	return wm->dig[2] & WM9705_PDEN;
210}
211
212/*
213 * Read a sample from the WM9705 adc in polling mode.
214 */
215static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
216{
217	int timeout = 5 * delay;
218	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
219
220	if (wants_pen && !wm->pen_probably_down) {
221		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
222		if (!(data & WM97XX_PEN_DOWN))
223			return RC_PENUP;
224		wm->pen_probably_down = 1;
225	}
226
227	/* set up digitiser */
228	if (wm->mach_ops && wm->mach_ops->pre_sample)
229		wm->mach_ops->pre_sample(adcsel);
230	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
231				| WM97XX_POLL | WM97XX_DELAY(delay));
232
233	/* wait 3 AC97 time slots + delay for conversion */
234	poll_delay(delay);
235
236	/* wait for POLL to go low */
237	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
238	       && timeout) {
239		udelay(AC97_LINK_FRAME);
240		timeout--;
241	}
242
243	if (timeout == 0) {
244		/* If PDEN is set, we can get a timeout when pen goes up */
245		if (is_pden(wm))
246			wm->pen_probably_down = 0;
247		else
248			dev_dbg(wm->dev, "adc sample timeout");
249		return RC_PENUP;
250	}
251
252	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
253	if (wm->mach_ops && wm->mach_ops->post_sample)
254		wm->mach_ops->post_sample(adcsel);
255
256	/* check we have correct sample */
257	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
258		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
259			adcsel & WM97XX_ADCSEL_MASK,
260			*sample & WM97XX_ADCSEL_MASK);
261		return RC_PENUP;
262	}
263
264	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
265		wm->pen_probably_down = 0;
266		return RC_PENUP;
267	}
268
269	return RC_VALID;
270}
271
272/*
273 * Sample the WM9705 touchscreen in polling mode
274 */
275static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
276{
277	int rc;
278
279	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
280	if (rc != RC_VALID)
281		return rc;
282	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
283	if (rc != RC_VALID)
284		return rc;
285	if (pil) {
286		rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN, &data->p);
287		if (rc != RC_VALID)
288			return rc;
289	} else
290		data->p = DEFAULT_PRESSURE;
291
292	return RC_VALID;
293}
294
295/*
296 * Enable WM9705 continuous mode, i.e. touch data is streamed across
297 * an AC97 slot
298 */
299static int wm9705_acc_enable(struct wm97xx *wm, int enable)
300{
301	u16 dig1, dig2;
302	int ret = 0;
303
304	dig1 = wm->dig[1];
305	dig2 = wm->dig[2];
306
307	if (enable) {
308		/* continuous mode */
309		if (wm->mach_ops->acc_startup &&
310		    (ret = wm->mach_ops->acc_startup(wm)) < 0)
311			return ret;
312		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
313			  WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
314		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
315			WM97XX_DELAY(delay) |
316			WM97XX_SLT(wm->acc_slot) |
317			WM97XX_RATE(wm->acc_rate);
318		if (pil)
319			dig1 |= WM97XX_ADCSEL_PRES;
320		dig2 |= WM9705_PDEN;
321	} else {
322		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
323		dig2 &= ~WM9705_PDEN;
324		if (wm->mach_ops->acc_shutdown)
325			wm->mach_ops->acc_shutdown(wm);
326	}
327
328	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
329	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
330
331	return ret;
332}
333
334struct wm97xx_codec_drv wm9705_codec = {
335	.id = WM9705_ID2,
336	.name = "wm9705",
337	.poll_sample = wm9705_poll_sample,
338	.poll_touch = wm9705_poll_touch,
339	.acc_enable = wm9705_acc_enable,
340	.phy_init = wm9705_phy_init,
341	.dig_enable = wm9705_dig_enable,
342	.dig_restore = wm9705_dig_restore,
343	.aux_prepare = wm9705_aux_prepare,
344};
345EXPORT_SYMBOL_GPL(wm9705_codec);
346
347/* Module information */
348MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
349MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
350MODULE_LICENSE("GPL");
351