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