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 */
37static int rpu = 8;
38module_param(rpu, int, 0);
39MODULE_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 */
51static int pil;
52module_param(pil, int, 0);
53MODULE_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 */
60static int pressure = DEFAULT_PRESSURE & 0xfff;
61module_param(pressure, int, 0);
62MODULE_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 */
76static int delay = 4;
77module_param(delay, int, 0);
78MODULE_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 */
85static int five_wire;
86module_param(five_wire, int, 0);
87MODULE_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 */
102static int mask;
103module_param(mask, int, 0);
104MODULE_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 */
112static int coord;
113module_param(coord, int, 0);
114MODULE_PARM_DESC(coord, "Polling coordinate mode");
115
116/*
117 * ADC sample delay times in uS
118 */
119static 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 */
143static 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 */
151static 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
214static 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
232static 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
239static 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
247static 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 */
255static 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 */
320static 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;
383err:
384	return 0;
385}
386
387/*
388 * Sample the WM9713 touchscreen in polling mode
389 */
390static 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 */
420static 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
460struct 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};
471EXPORT_SYMBOL_GPL(wm9713_codec);
472
473/* Module information */
474MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
475MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
476MODULE_LICENSE("GPL");
477