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 */
38 static int pil;
39 module_param(pil, int, 0);
40 MODULE_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 */
47 static int pressure = DEFAULT_PRESSURE & 0xfff;
48 module_param(pressure, int, 0);
49 MODULE_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 */
63 static int delay = 4;
64 module_param(delay, int, 0);
65 MODULE_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 */
77 static int pdd = 8;
78 module_param(pdd, int, 0);
79 MODULE_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 */
94 static int mask;
95 module_param(mask, int, 0);
96 MODULE_PARM_DESC(mask, "Set adc mask function.");
97
98 /*
99 * ADC sample delay times in uS
100 */
101 static 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 */
poll_delay(int d)125 static 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 */
wm9705_phy_init(struct wm97xx * wm)133 static 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
wm9705_dig_enable(struct wm97xx * wm,int enable)178 static 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
wm9705_aux_prepare(struct wm97xx * wm)189 static 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
wm9705_dig_restore(struct wm97xx * wm)196 static 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
is_pden(struct wm97xx * wm)202 static 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 */
wm9705_poll_sample(struct wm97xx * wm,int adcsel,int * sample)210 static 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 */
wm9705_poll_touch(struct wm97xx * wm,struct wm97xx_data * data)270 static 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 */
wm9705_acc_enable(struct wm97xx * wm,int enable)294 static 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
329 struct 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 };
340 EXPORT_SYMBOL_GPL(wm9705_codec);
341
342 /* Module information */
343 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
344 MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
345 MODULE_LICENSE("GPL");
346