wm9713.c

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