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 */
43 static int pil;
44 module_param(pil, int, 0);
45 MODULE_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 */
52 static int pressure = DEFAULT_PRESSURE & 0xfff;
53 module_param(pressure, int, 0);
54 MODULE_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 */
68 static int delay = 4;
69 module_param(delay, int, 0);
70 MODULE_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 */
82 static int pdd = 8;
83 module_param(pdd, int, 0);
84 MODULE_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 */
99 static int mask;
100 module_param(mask, int, 0);
101 MODULE_PARM_DESC(mask, "Set adc mask function.");
102
103 /*
104 * ADC sample delay times in uS
105 */
106 static 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 */
poll_delay(int d)130 static 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 */
wm9705_phy_init(struct wm97xx * wm)138 static 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
wm9705_dig_enable(struct wm97xx * wm,int enable)183 static 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
wm9705_aux_prepare(struct wm97xx * wm)194 static 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
wm9705_dig_restore(struct wm97xx * wm)201 static 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
is_pden(struct wm97xx * wm)207 static 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 */
wm9705_poll_sample(struct wm97xx * wm,int adcsel,int * sample)215 static 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 */
wm9705_poll_touch(struct wm97xx * wm,struct wm97xx_data * data)275 static 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 */
wm9705_acc_enable(struct wm97xx * wm,int enable)299 static 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
334 struct 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 };
345 EXPORT_SYMBOL_GPL(wm9705_codec);
346
347 /* Module information */
348 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
349 MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
350 MODULE_LICENSE("GPL");
351