wm9712.c

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