1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * wm9712.c  --  Codec driver for Wolfson WM9712 AC97 Codecs.
4  *
5  * Copyright 2003, 2004, 2005, 2006, 2007 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 WM9712_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 = 3;
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  */
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 WM9712
150  */
151 static void wm9712_phy_init(struct wm97xx *wm)
152 {
153 	u16 dig1 = 0;
154 	u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
155 
156 	/* WM9712 rpu */
157 	if (rpu) {
158 		dig2 &= 0xffc0;
159 		dig2 |= WM9712_RPU(rpu);
160 		dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms\n",
161 			64000 / rpu);
162 	}
163 
164 	/* WM9712 five wire */
165 	if (five_wire) {
166 		dig2 |= WM9712_45W;
167 		dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n");
168 
169 		if (pil) {
170 			dev_warn(wm->dev, "pressure measurement is not "
171 				 "supported in 5-wire mode\n");
172 			pil = 0;
173 		}
174 	}
175 
176 	/* touchpanel pressure current*/
177 	if (pil == 2) {
178 		dig2 |= WM9712_PIL;
179 		dev_dbg(wm->dev,
180 			"setting pressure measurement current to 400uA.\n");
181 	} else if (pil)
182 		dev_dbg(wm->dev,
183 			"setting pressure measurement current to 200uA.\n");
184 	if (!pil)
185 		pressure = 0;
186 
187 	/* polling mode sample settling delay */
188 	if (delay < 0 || delay > 15) {
189 		dev_dbg(wm->dev, "supplied delay out of range.\n");
190 		delay = 4;
191 	}
192 	dig1 &= 0xff0f;
193 	dig1 |= WM97XX_DELAY(delay);
194 	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n",
195 		delay_table[delay]);
196 
197 	/* mask */
198 	dig2 |= ((mask & 0x3) << 6);
199 	if (mask) {
200 		u16 reg;
201 		/* Set GPIO4 as Mask Pin*/
202 		reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
203 		wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
204 		reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
205 		wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
206 	}
207 
208 	/* wait - coord mode */
209 	if (coord)
210 		dig2 |= WM9712_WAIT;
211 
212 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
213 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
214 }
215 
216 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
217 {
218 	u16 dig2 = wm->dig[2];
219 
220 	if (enable) {
221 		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
222 				 dig2 | WM97XX_PRP_DET_DIG);
223 		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
224 	} else
225 		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
226 				 dig2 & ~WM97XX_PRP_DET_DIG);
227 }
228 
229 static void wm9712_aux_prepare(struct wm97xx *wm)
230 {
231 	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
232 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
233 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
234 }
235 
236 static void wm9712_dig_restore(struct wm97xx *wm)
237 {
238 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
239 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
240 }
241 
242 static inline int is_pden(struct wm97xx *wm)
243 {
244 	return wm->dig[2] & WM9712_PDEN;
245 }
246 
247 /*
248  * Read a sample from the WM9712 adc in polling mode.
249  */
250 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
251 {
252 	int timeout = 5 * delay;
253 	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
254 
255 	if (wants_pen && !wm->pen_probably_down) {
256 		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
257 		if (!(data & WM97XX_PEN_DOWN))
258 			return RC_PENUP;
259 		wm->pen_probably_down = 1;
260 	}
261 
262 	/* set up digitiser */
263 	if (wm->mach_ops && wm->mach_ops->pre_sample)
264 		wm->mach_ops->pre_sample(adcsel);
265 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
266 				| WM97XX_POLL | WM97XX_DELAY(delay));
267 
268 	/* wait 3 AC97 time slots + delay for conversion */
269 	poll_delay(delay);
270 
271 	/* wait for POLL to go low */
272 	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
273 	       && timeout) {
274 		udelay(AC97_LINK_FRAME);
275 		timeout--;
276 	}
277 
278 	if (timeout <= 0) {
279 		/* If PDEN is set, we can get a timeout when pen goes up */
280 		if (is_pden(wm))
281 			wm->pen_probably_down = 0;
282 		else
283 			dev_dbg(wm->dev, "adc sample timeout\n");
284 		return RC_PENUP;
285 	}
286 
287 	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
288 	if (wm->mach_ops && wm->mach_ops->post_sample)
289 		wm->mach_ops->post_sample(adcsel);
290 
291 	/* check we have correct sample */
292 	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
293 		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x\n",
294 			adcsel & WM97XX_ADCSEL_MASK,
295 			*sample & WM97XX_ADCSEL_MASK);
296 		return RC_AGAIN;
297 	}
298 
299 	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
300 		/* Sometimes it reads a wrong value the first time. */
301 		*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
302 		if (!(*sample & WM97XX_PEN_DOWN)) {
303 			wm->pen_probably_down = 0;
304 			return RC_PENUP;
305 		}
306 	}
307 
308 	return RC_VALID;
309 }
310 
311 /*
312  * Read a coord from the WM9712 adc in polling mode.
313  */
314 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
315 {
316 	int timeout = 5 * delay;
317 
318 	if (!wm->pen_probably_down) {
319 		u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
320 		if (!(data_rd & WM97XX_PEN_DOWN))
321 			return RC_PENUP;
322 		wm->pen_probably_down = 1;
323 	}
324 
325 	/* set up digitiser */
326 	if (wm->mach_ops && wm->mach_ops->pre_sample)
327 		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
328 
329 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
330 		WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
331 
332 	/* wait 3 AC97 time slots + delay for conversion and read x */
333 	poll_delay(delay);
334 	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
335 	/* wait for POLL to go low */
336 	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
337 	       && timeout) {
338 		udelay(AC97_LINK_FRAME);
339 		timeout--;
340 	}
341 
342 	if (timeout <= 0) {
343 		/* If PDEN is set, we can get a timeout when pen goes up */
344 		if (is_pden(wm))
345 			wm->pen_probably_down = 0;
346 		else
347 			dev_dbg(wm->dev, "adc sample timeout\n");
348 		return RC_PENUP;
349 	}
350 
351 	/* read back y data */
352 	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
353 	if (pil)
354 		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
355 	else
356 		data->p = DEFAULT_PRESSURE;
357 
358 	if (wm->mach_ops && wm->mach_ops->post_sample)
359 		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
360 
361 	/* check we have correct sample */
362 	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
363 		goto err;
364 	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
365 		goto err;
366 
367 	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
368 		wm->pen_probably_down = 0;
369 		return RC_PENUP;
370 	}
371 	return RC_VALID;
372 err:
373 	return 0;
374 }
375 
376 /*
377  * Sample the WM9712 touchscreen in polling mode
378  */
379 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
380 {
381 	int rc;
382 
383 	if (coord) {
384 		rc = wm9712_poll_coord(wm, data);
385 		if (rc != RC_VALID)
386 			return rc;
387 	} else {
388 		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN,
389 					&data->x);
390 		if (rc != RC_VALID)
391 			return rc;
392 
393 		rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN,
394 					&data->y);
395 		if (rc != RC_VALID)
396 			return rc;
397 
398 		if (pil && !five_wire) {
399 			rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
400 						&data->p);
401 			if (rc != RC_VALID)
402 				return rc;
403 		} else
404 			data->p = DEFAULT_PRESSURE;
405 	}
406 	return RC_VALID;
407 }
408 
409 /*
410  * Enable WM9712 continuous mode, i.e. touch data is streamed across
411  * an AC97 slot
412  */
413 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
414 {
415 	u16 dig1, dig2;
416 	int ret = 0;
417 
418 	dig1 = wm->dig[1];
419 	dig2 = wm->dig[2];
420 
421 	if (enable) {
422 		/* continuous mode */
423 		if (wm->mach_ops->acc_startup) {
424 			ret = wm->mach_ops->acc_startup(wm);
425 			if (ret < 0)
426 				return ret;
427 		}
428 		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
429 			WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
430 		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
431 			WM97XX_DELAY(delay) |
432 			WM97XX_SLT(wm->acc_slot) |
433 			WM97XX_RATE(wm->acc_rate);
434 		if (pil)
435 			dig1 |= WM97XX_ADCSEL_PRES;
436 		dig2 |= WM9712_PDEN;
437 	} else {
438 		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
439 		dig2 &= ~WM9712_PDEN;
440 		if (wm->mach_ops->acc_shutdown)
441 			wm->mach_ops->acc_shutdown(wm);
442 	}
443 
444 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
445 	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
446 
447 	return 0;
448 }
449 
450 struct wm97xx_codec_drv wm9712_codec = {
451 	.id = WM9712_ID2,
452 	.name = "wm9712",
453 	.poll_sample = wm9712_poll_sample,
454 	.poll_touch = wm9712_poll_touch,
455 	.acc_enable = wm9712_acc_enable,
456 	.phy_init = wm9712_phy_init,
457 	.dig_enable = wm9712_dig_enable,
458 	.dig_restore = wm9712_dig_restore,
459 	.aux_prepare = wm9712_aux_prepare,
460 };
461 EXPORT_SYMBOL_GPL(wm9712_codec);
462 
463 /* Module information */
464 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
465 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
466 MODULE_LICENSE("GPL");
467