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 */
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 = 3;
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 WM9712
150 */
151static 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
216static 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
229static 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
236static 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
242static 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 */
250static 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 */
314static 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;
372err:
373	return 0;
374}
375
376/*
377 * Sample the WM9712 touchscreen in polling mode
378 */
379static 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 */
413static 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
450struct 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};
461EXPORT_SYMBOL_GPL(wm9712_codec);
462
463/* Module information */
464MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
465MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
466MODULE_LICENSE("GPL");
467