1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
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 WM9705_VERSION		"1.00"
22#define DEFAULT_PRESSURE	0xb0c0
23
24/*
25 * Module parameters
26 */
27
28/*
29 * Set current used for pressure measurement.
30 *
31 * Set pil = 2 to use 400uA
32 *     pil = 1 to use 200uA and
33 *     pil = 0 to disable pressure measurement.
34 *
35 * This is used to increase the range of values returned by the adc
36 * when measureing touchpanel pressure.
37 */
38static int pil;
39module_param(pil, int, 0);
40MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
41
42/*
43 * Set threshold for pressure measurement.
44 *
45 * Pen down pressure below threshold is ignored.
46 */
47static int pressure = DEFAULT_PRESSURE & 0xfff;
48module_param(pressure, int, 0);
49MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
50
51/*
52 * Set adc sample delay.
53 *
54 * For accurate touchpanel measurements, some settling time may be
55 * required between the switch matrix applying a voltage across the
56 * touchpanel plate and the ADC sampling the signal.
57 *
58 * This delay can be set by setting delay = n, where n is the array
59 * position of the delay in the array delay_table below.
60 * Long delays > 1ms are supported for completeness, but are not
61 * recommended.
62 */
63static int delay = 4;
64module_param(delay, int, 0);
65MODULE_PARM_DESC(delay, "Set adc sample delay.");
66
67/*
68 * Pen detect comparator threshold.
69 *
70 * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
71 * i.e. 1 =  Vmid/15 threshold
72 *      15 =  Vmid/1 threshold
73 *
74 * Adjust this value if you are having problems with pen detect not
75 * detecting any down events.
76 */
77static int pdd = 8;
78module_param(pdd, int, 0);
79MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
80
81/*
82 * Set adc mask function.
83 *
84 * Sources of glitch noise, such as signals driving an LCD display, may feed
85 * through to the touch screen plates and affect measurement accuracy. In
86 * order to minimise this, a signal may be applied to the MASK pin to delay or
87 * synchronise the sampling.
88 *
89 * 0 = No delay or sync
90 * 1 = High on pin stops conversions
91 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
92 * 3 = Edge triggered, edge on pin starts conversion after delay param
93 */
94static int mask;
95module_param(mask, int, 0);
96MODULE_PARM_DESC(mask, "Set adc mask function.");
97
98/*
99 * ADC sample delay times in uS
100 */
101static const int delay_table[] = {
102	21,    /* 1 AC97 Link frames */
103	42,    /* 2                  */
104	84,    /* 4                  */
105	167,   /* 8                  */
106	333,   /* 16                 */
107	667,   /* 32                 */
108	1000,  /* 48                 */
109	1333,  /* 64                 */
110	2000,  /* 96                 */
111	2667,  /* 128                */
112	3333,  /* 160                */
113	4000,  /* 192                */
114	4667,  /* 224                */
115	5333,  /* 256                */
116	6000,  /* 288                */
117	0      /* No delay, switch matrix always on */
118};
119
120/*
121 * Delay after issuing a POLL command.
122 *
123 * The delay is 3 AC97 link frames + the touchpanel settling delay
124 */
125static inline void poll_delay(int d)
126{
127	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
128}
129
130/*
131 * set up the physical settings of the WM9705
132 */
133static void wm9705_phy_init(struct wm97xx *wm)
134{
135	u16 dig1 = 0, dig2 = WM97XX_RPR;
136
137	/*
138	* mute VIDEO and AUX as they share X and Y touchscreen
139	* inputs on the WM9705
140	*/
141	wm97xx_reg_write(wm, AC97_AUX, 0x8000);
142	wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
143
144	/* touchpanel pressure current*/
145	if (pil == 2) {
146		dig2 |= WM9705_PIL;
147		dev_dbg(wm->dev,
148			"setting pressure measurement current to 400uA.");
149	} else if (pil)
150		dev_dbg(wm->dev,
151			"setting pressure measurement current to 200uA.");
152	if (!pil)
153		pressure = 0;
154
155	/* polling mode sample settling delay */
156	if (delay != 4) {
157		if (delay < 0 || delay > 15) {
158			dev_dbg(wm->dev, "supplied delay out of range.");
159			delay = 4;
160		}
161	}
162	dig1 &= 0xff0f;
163	dig1 |= WM97XX_DELAY(delay);
164	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
165		delay_table[delay]);
166
167	/* WM9705 pdd */
168	dig2 |= (pdd & 0x000f);
169	dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
170
171	/* mask */
172	dig2 |= ((mask & 0x3) << 4);
173
174	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
175	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
176}
177
178static void wm9705_dig_enable(struct wm97xx *wm, int enable)
179{
180	if (enable) {
181		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
182				 wm->dig[2] | WM97XX_PRP_DET_DIG);
183		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
184	} else
185		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
186				 wm->dig[2] & ~WM97XX_PRP_DET_DIG);
187}
188
189static void wm9705_aux_prepare(struct wm97xx *wm)
190{
191	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
192	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
193	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
194}
195
196static void wm9705_dig_restore(struct wm97xx *wm)
197{
198	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
199	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
200}
201
202static inline int is_pden(struct wm97xx *wm)
203{
204	return wm->dig[2] & WM9705_PDEN;
205}
206
207/*
208 * Read a sample from the WM9705 adc in polling mode.
209 */
210static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
211{
212	int timeout = 5 * delay;
213	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
214
215	if (wants_pen && !wm->pen_probably_down) {
216		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
217		if (!(data & WM97XX_PEN_DOWN))
218			return RC_PENUP;
219		wm->pen_probably_down = 1;
220	}
221
222	/* set up digitiser */
223	if (wm->mach_ops && wm->mach_ops->pre_sample)
224		wm->mach_ops->pre_sample(adcsel);
225	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
226				| WM97XX_POLL | WM97XX_DELAY(delay));
227
228	/* wait 3 AC97 time slots + delay for conversion */
229	poll_delay(delay);
230
231	/* wait for POLL to go low */
232	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
233	       && timeout) {
234		udelay(AC97_LINK_FRAME);
235		timeout--;
236	}
237
238	if (timeout == 0) {
239		/* If PDEN is set, we can get a timeout when pen goes up */
240		if (is_pden(wm))
241			wm->pen_probably_down = 0;
242		else
243			dev_dbg(wm->dev, "adc sample timeout");
244		return RC_PENUP;
245	}
246
247	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
248	if (wm->mach_ops && wm->mach_ops->post_sample)
249		wm->mach_ops->post_sample(adcsel);
250
251	/* check we have correct sample */
252	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
253		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
254			adcsel & WM97XX_ADCSEL_MASK,
255			*sample & WM97XX_ADCSEL_MASK);
256		return RC_PENUP;
257	}
258
259	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
260		wm->pen_probably_down = 0;
261		return RC_PENUP;
262	}
263
264	return RC_VALID;
265}
266
267/*
268 * Sample the WM9705 touchscreen in polling mode
269 */
270static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
271{
272	int rc;
273
274	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
275	if (rc != RC_VALID)
276		return rc;
277	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
278	if (rc != RC_VALID)
279		return rc;
280	if (pil) {
281		rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN, &data->p);
282		if (rc != RC_VALID)
283			return rc;
284	} else
285		data->p = DEFAULT_PRESSURE;
286
287	return RC_VALID;
288}
289
290/*
291 * Enable WM9705 continuous mode, i.e. touch data is streamed across
292 * an AC97 slot
293 */
294static int wm9705_acc_enable(struct wm97xx *wm, int enable)
295{
296	u16 dig1, dig2;
297	int ret = 0;
298
299	dig1 = wm->dig[1];
300	dig2 = wm->dig[2];
301
302	if (enable) {
303		/* continuous mode */
304		if (wm->mach_ops->acc_startup &&
305		    (ret = wm->mach_ops->acc_startup(wm)) < 0)
306			return ret;
307		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
308			  WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
309		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
310			WM97XX_DELAY(delay) |
311			WM97XX_SLT(wm->acc_slot) |
312			WM97XX_RATE(wm->acc_rate);
313		if (pil)
314			dig1 |= WM97XX_ADCSEL_PRES;
315		dig2 |= WM9705_PDEN;
316	} else {
317		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
318		dig2 &= ~WM9705_PDEN;
319		if (wm->mach_ops->acc_shutdown)
320			wm->mach_ops->acc_shutdown(wm);
321	}
322
323	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
324	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
325
326	return ret;
327}
328
329struct wm97xx_codec_drv wm9705_codec = {
330	.id = WM9705_ID2,
331	.name = "wm9705",
332	.poll_sample = wm9705_poll_sample,
333	.poll_touch = wm9705_poll_touch,
334	.acc_enable = wm9705_acc_enable,
335	.phy_init = wm9705_phy_init,
336	.dig_enable = wm9705_dig_enable,
337	.dig_restore = wm9705_dig_restore,
338	.aux_prepare = wm9705_aux_prepare,
339};
340EXPORT_SYMBOL_GPL(wm9705_codec);
341
342/* Module information */
343MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
344MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
345MODULE_LICENSE("GPL");
346