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 */ 38 static int rpu = 8; 39 module_param(rpu, int, 0); 40 MODULE_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 */ 52 static int pil; 53 module_param(pil, int, 0); 54 MODULE_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 */ 61 static int pressure = DEFAULT_PRESSURE & 0xfff; 62 module_param(pressure, int, 0); 63 MODULE_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 */ 77 static int delay = 3; 78 module_param(delay, int, 0); 79 MODULE_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 */ 86 static int five_wire; 87 module_param(five_wire, int, 0); 88 MODULE_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 */ 103 static int mask; 104 module_param(mask, int, 0); 105 MODULE_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 */ 113 static int coord; 114 module_param(coord, int, 0); 115 MODULE_PARM_DESC(coord, "Polling coordinate mode"); 116 117 /* 118 * ADC sample delay times in uS 119 */ 120 static 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 */ 144 static 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 */ 152 static 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 } 216 217 static 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 } 229 230 static 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 } 236 237 static 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 } 242 243 static 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 */ 251 static 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 */ 315 static 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; 373 err: 374 return 0; 375 } 376 377 /* 378 * Sample the WM9712 touchscreen in polling mode 379 */ 380 static 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 */ 414 static 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 } 450 451 struct 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 }; 462 EXPORT_SYMBOL_GPL(wm9712_codec); 463 464 /* Module information */ 465 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>"); 466 MODULE_DESCRIPTION("WM9712 Touch Screen Driver"); 467 MODULE_LICENSE("GPL"); 468