1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * wm9713.c -- Codec touch driver for Wolfson WM9713 AC97 Codec.
4 *
5 * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
6 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
7 * Parts Copyright : Ian Molton <spyro@f2s.com>
8 * Andrew Zabolotny <zap@homelink.ru>
9 * Russell King <rmk@arm.linux.org.uk>
10 */
11
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/kernel.h>
15 #include <linux/input.h>
16 #include <linux/delay.h>
17 #include <linux/bitops.h>
18 #include <linux/wm97xx.h>
19
20 #define TS_NAME "wm97xx"
21 #define WM9713_VERSION "1.00"
22 #define DEFAULT_PRESSURE 0xb0c0
23
24 /*
25 * Module parameters
26 */
27
28 /*
29 * Set internal pull up for pen detect.
30 *
31 * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
32 * i.e. pull up resistance = 64k Ohms / rpu.
33 *
34 * Adjust this value if you are having problems with pen detect not
35 * detecting any down event.
36 */
37 static int rpu = 8;
38 module_param(rpu, int, 0);
39 MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect.");
40
41 /*
42 * Set current used for pressure measurement.
43 *
44 * Set pil = 2 to use 400uA
45 * pil = 1 to use 200uA and
46 * pil = 0 to disable pressure measurement.
47 *
48 * This is used to increase the range of values returned by the adc
49 * when measureing touchpanel pressure.
50 */
51 static int pil;
52 module_param(pil, int, 0);
53 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
54
55 /*
56 * Set threshold for pressure measurement.
57 *
58 * Pen down pressure below threshold is ignored.
59 */
60 static int pressure = DEFAULT_PRESSURE & 0xfff;
61 module_param(pressure, int, 0);
62 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
63
64 /*
65 * Set adc sample delay.
66 *
67 * For accurate touchpanel measurements, some settling time may be
68 * required between the switch matrix applying a voltage across the
69 * touchpanel plate and the ADC sampling the signal.
70 *
71 * This delay can be set by setting delay = n, where n is the array
72 * position of the delay in the array delay_table below.
73 * Long delays > 1ms are supported for completeness, but are not
74 * recommended.
75 */
76 static int delay = 4;
77 module_param(delay, int, 0);
78 MODULE_PARM_DESC(delay, "Set adc sample delay.");
79
80 /*
81 * Set five_wire = 1 to use a 5 wire touchscreen.
82 *
83 * NOTE: Five wire mode does not allow for readback of pressure.
84 */
85 static int five_wire;
86 module_param(five_wire, int, 0);
87 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
88
89 /*
90 * Set adc mask function.
91 *
92 * Sources of glitch noise, such as signals driving an LCD display, may feed
93 * through to the touch screen plates and affect measurement accuracy. In
94 * order to minimise this, a signal may be applied to the MASK pin to delay or
95 * synchronise the sampling.
96 *
97 * 0 = No delay or sync
98 * 1 = High on pin stops conversions
99 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
100 * 3 = Edge triggered, edge on pin starts conversion after delay param
101 */
102 static int mask;
103 module_param(mask, int, 0);
104 MODULE_PARM_DESC(mask, "Set adc mask function.");
105
106 /*
107 * Coordinate Polling Enable.
108 *
109 * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
110 * for every poll.
111 */
112 static int coord;
113 module_param(coord, int, 0);
114 MODULE_PARM_DESC(coord, "Polling coordinate mode");
115
116 /*
117 * ADC sample delay times in uS
118 */
119 static const int delay_table[] = {
120 21, /* 1 AC97 Link frames */
121 42, /* 2 */
122 84, /* 4 */
123 167, /* 8 */
124 333, /* 16 */
125 667, /* 32 */
126 1000, /* 48 */
127 1333, /* 64 */
128 2000, /* 96 */
129 2667, /* 128 */
130 3333, /* 160 */
131 4000, /* 192 */
132 4667, /* 224 */
133 5333, /* 256 */
134 6000, /* 288 */
135 0 /* No delay, switch matrix always on */
136 };
137
138 /*
139 * Delay after issuing a POLL command.
140 *
141 * The delay is 3 AC97 link frames + the touchpanel settling delay
142 */
poll_delay(int d)143 static inline void poll_delay(int d)
144 {
145 udelay(3 * AC97_LINK_FRAME + delay_table[d]);
146 }
147
148 /*
149 * set up the physical settings of the WM9713
150 */
wm9713_phy_init(struct wm97xx * wm)151 static void wm9713_phy_init(struct wm97xx *wm)
152 {
153 u16 dig1 = 0, dig2, dig3;
154
155 /* default values */
156 dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
157 dig3 = WM9712_RPU(1);
158
159 /* rpu */
160 if (rpu) {
161 dig3 &= 0xffc0;
162 dig3 |= WM9712_RPU(rpu);
163 dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
164 64000 / rpu);
165 }
166
167 /* Five wire panel? */
168 if (five_wire) {
169 dig3 |= WM9713_45W;
170 dev_info(wm->dev, "setting 5-wire touchscreen mode.");
171
172 if (pil) {
173 dev_warn(wm->dev,
174 "Pressure measurement not supported in 5 "
175 "wire mode, disabling\n");
176 pil = 0;
177 }
178 }
179
180 /* touchpanel pressure */
181 if (pil == 2) {
182 dig3 |= WM9712_PIL;
183 dev_info(wm->dev,
184 "setting pressure measurement current to 400uA.");
185 } else if (pil)
186 dev_info(wm->dev,
187 "setting pressure measurement current to 200uA.");
188 if (!pil)
189 pressure = 0;
190
191 /* sample settling delay */
192 if (delay < 0 || delay > 15) {
193 dev_info(wm->dev, "supplied delay out of range.");
194 delay = 4;
195 dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
196 delay_table[delay]);
197 }
198 dig2 &= 0xff0f;
199 dig2 |= WM97XX_DELAY(delay);
200
201 /* mask */
202 dig3 |= ((mask & 0x3) << 4);
203 if (coord)
204 dig3 |= WM9713_WAIT;
205
206 wm->misc = wm97xx_reg_read(wm, 0x5a);
207
208 wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
209 wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
210 wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
211 wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
212 }
213
wm9713_dig_enable(struct wm97xx * wm,int enable)214 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
215 {
216 u16 val;
217
218 if (enable) {
219 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
220 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
221 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
222 WM97XX_PRP_DET_DIG);
223 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
224 } else {
225 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
226 ~WM97XX_PRP_DET_DIG);
227 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
228 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
229 }
230 }
231
wm9713_dig_restore(struct wm97xx * wm)232 static void wm9713_dig_restore(struct wm97xx *wm)
233 {
234 wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
235 wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
236 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
237 }
238
wm9713_aux_prepare(struct wm97xx * wm)239 static void wm9713_aux_prepare(struct wm97xx *wm)
240 {
241 memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
242 wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
243 wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
244 wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
245 }
246
is_pden(struct wm97xx * wm)247 static inline int is_pden(struct wm97xx *wm)
248 {
249 return wm->dig[2] & WM9713_PDEN;
250 }
251
252 /*
253 * Read a sample from the WM9713 adc in polling mode.
254 */
wm9713_poll_sample(struct wm97xx * wm,int adcsel,int * sample)255 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
256 {
257 u16 dig1;
258 int timeout = 5 * delay;
259 bool wants_pen = adcsel & WM97XX_PEN_DOWN;
260
261 if (wants_pen && !wm->pen_probably_down) {
262 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
263 if (!(data & WM97XX_PEN_DOWN))
264 return RC_PENUP;
265 wm->pen_probably_down = 1;
266 }
267
268 /* set up digitiser */
269 dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
270 dig1 &= ~WM9713_ADCSEL_MASK;
271 /* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
272 dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
273
274 if (wm->mach_ops && wm->mach_ops->pre_sample)
275 wm->mach_ops->pre_sample(adcsel);
276 wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | WM9713_POLL);
277
278 /* wait 3 AC97 time slots + delay for conversion */
279 poll_delay(delay);
280
281 /* wait for POLL to go low */
282 while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
283 timeout) {
284 udelay(AC97_LINK_FRAME);
285 timeout--;
286 }
287
288 if (timeout <= 0) {
289 /* If PDEN is set, we can get a timeout when pen goes up */
290 if (is_pden(wm))
291 wm->pen_probably_down = 0;
292 else
293 dev_dbg(wm->dev, "adc sample timeout");
294 return RC_PENUP;
295 }
296
297 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
298 if (wm->mach_ops && wm->mach_ops->post_sample)
299 wm->mach_ops->post_sample(adcsel);
300
301 /* check we have correct sample */
302 if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
303 dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
304 adcsel & WM97XX_ADCSEL_MASK,
305 *sample & WM97XX_ADCSEL_MASK);
306 return RC_PENUP;
307 }
308
309 if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
310 wm->pen_probably_down = 0;
311 return RC_PENUP;
312 }
313
314 return RC_VALID;
315 }
316
317 /*
318 * Read a coordinate from the WM9713 adc in polling mode.
319 */
wm9713_poll_coord(struct wm97xx * wm,struct wm97xx_data * data)320 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
321 {
322 u16 dig1;
323 int timeout = 5 * delay;
324
325 if (!wm->pen_probably_down) {
326 u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
327 if (!(val & WM97XX_PEN_DOWN))
328 return RC_PENUP;
329 wm->pen_probably_down = 1;
330 }
331
332 /* set up digitiser */
333 dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
334 dig1 &= ~WM9713_ADCSEL_MASK;
335 if (pil)
336 dig1 |= WM9713_ADCSEL_PRES;
337
338 if (wm->mach_ops && wm->mach_ops->pre_sample)
339 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
340 wm97xx_reg_write(wm, AC97_WM9713_DIG1,
341 dig1 | WM9713_POLL | WM9713_COO);
342
343 /* wait 3 AC97 time slots + delay for conversion */
344 poll_delay(delay);
345 data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
346 /* wait for POLL to go low */
347 while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
348 && timeout) {
349 udelay(AC97_LINK_FRAME);
350 timeout--;
351 }
352
353 if (timeout <= 0) {
354 /* If PDEN is set, we can get a timeout when pen goes up */
355 if (is_pden(wm))
356 wm->pen_probably_down = 0;
357 else
358 dev_dbg(wm->dev, "adc sample timeout");
359 return RC_PENUP;
360 }
361
362 /* read back data */
363 data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
364 if (pil)
365 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
366 else
367 data->p = DEFAULT_PRESSURE;
368
369 if (wm->mach_ops && wm->mach_ops->post_sample)
370 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
371
372 /* check we have correct sample */
373 if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
374 goto err;
375 if (pil && !(data->p & WM97XX_ADCSEL_PRES))
376 goto err;
377
378 if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
379 wm->pen_probably_down = 0;
380 return RC_PENUP;
381 }
382 return RC_VALID;
383 err:
384 return 0;
385 }
386
387 /*
388 * Sample the WM9713 touchscreen in polling mode
389 */
wm9713_poll_touch(struct wm97xx * wm,struct wm97xx_data * data)390 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
391 {
392 int rc;
393
394 if (coord) {
395 rc = wm9713_poll_coord(wm, data);
396 if (rc != RC_VALID)
397 return rc;
398 } else {
399 rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
400 if (rc != RC_VALID)
401 return rc;
402 rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
403 if (rc != RC_VALID)
404 return rc;
405 if (pil) {
406 rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
407 &data->p);
408 if (rc != RC_VALID)
409 return rc;
410 } else
411 data->p = DEFAULT_PRESSURE;
412 }
413 return RC_VALID;
414 }
415
416 /*
417 * Enable WM9713 continuous mode, i.e. touch data is streamed across
418 * an AC97 slot
419 */
wm9713_acc_enable(struct wm97xx * wm,int enable)420 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
421 {
422 u16 dig1, dig2, dig3;
423 int ret = 0;
424
425 dig1 = wm->dig[0];
426 dig2 = wm->dig[1];
427 dig3 = wm->dig[2];
428
429 if (enable) {
430 /* continuous mode */
431 if (wm->mach_ops->acc_startup &&
432 (ret = wm->mach_ops->acc_startup(wm)) < 0)
433 return ret;
434
435 dig1 &= ~WM9713_ADCSEL_MASK;
436 dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
437 WM9713_ADCSEL_Y;
438 if (pil)
439 dig1 |= WM9713_ADCSEL_PRES;
440 dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK |
441 WM97XX_CM_RATE_MASK);
442 dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
443 WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
444 dig3 |= WM9713_PDEN;
445 } else {
446 dig1 &= ~(WM9713_CTC | WM9713_COO);
447 dig2 &= ~WM97XX_SLEN;
448 dig3 &= ~WM9713_PDEN;
449 if (wm->mach_ops->acc_shutdown)
450 wm->mach_ops->acc_shutdown(wm);
451 }
452
453 wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
454 wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
455 wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
456
457 return ret;
458 }
459
460 struct wm97xx_codec_drv wm9713_codec = {
461 .id = WM9713_ID2,
462 .name = "wm9713",
463 .poll_sample = wm9713_poll_sample,
464 .poll_touch = wm9713_poll_touch,
465 .acc_enable = wm9713_acc_enable,
466 .phy_init = wm9713_phy_init,
467 .dig_enable = wm9713_dig_enable,
468 .dig_restore = wm9713_dig_restore,
469 .aux_prepare = wm9713_aux_prepare,
470 };
471 EXPORT_SYMBOL_GPL(wm9713_codec);
472
473 /* Module information */
474 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
475 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
476 MODULE_LICENSE("GPL");
477