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/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 WM9712_VERSION "1.00" 22 #define DEFAULT_PRESSURE 0xb0c0 23 24 /* 25 * Module parameters 26 */ 27 28 /* 29 * Set internal pull up for pen detect. 30 * 31 * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive) 32 * i.e. pull up resistance = 64k Ohms / rpu. 33 * 34 * Adjust this value if you are having problems with pen detect not 35 * detecting any down event. 36 */ 37 static int rpu = 8; 38 module_param(rpu, int, 0); 39 MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect."); 40 41 /* 42 * Set current used for pressure measurement. 43 * 44 * Set pil = 2 to use 400uA 45 * pil = 1 to use 200uA and 46 * pil = 0 to disable pressure measurement. 47 * 48 * This is used to increase the range of values returned by the adc 49 * when measureing touchpanel pressure. 50 */ 51 static int pil; 52 module_param(pil, int, 0); 53 MODULE_PARM_DESC(pil, "Set current used for pressure measurement."); 54 55 /* 56 * Set threshold for pressure measurement. 57 * 58 * Pen down pressure below threshold is ignored. 59 */ 60 static int pressure = DEFAULT_PRESSURE & 0xfff; 61 module_param(pressure, int, 0); 62 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement."); 63 64 /* 65 * Set adc sample delay. 66 * 67 * For accurate touchpanel measurements, some settling time may be 68 * required between the switch matrix applying a voltage across the 69 * touchpanel plate and the ADC sampling the signal. 70 * 71 * This delay can be set by setting delay = n, where n is the array 72 * position of the delay in the array delay_table below. 73 * Long delays > 1ms are supported for completeness, but are not 74 * recommended. 75 */ 76 static int delay = 3; 77 module_param(delay, int, 0); 78 MODULE_PARM_DESC(delay, "Set adc sample delay."); 79 80 /* 81 * Set five_wire = 1 to use a 5 wire touchscreen. 82 * 83 * NOTE: Five wire mode does not allow for readback of pressure. 84 */ 85 static int five_wire; 86 module_param(five_wire, int, 0); 87 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen."); 88 89 /* 90 * Set adc mask function. 91 * 92 * Sources of glitch noise, such as signals driving an LCD display, may feed 93 * through to the touch screen plates and affect measurement accuracy. In 94 * order to minimise this, a signal may be applied to the MASK pin to delay or 95 * synchronise the sampling. 96 * 97 * 0 = No delay or sync 98 * 1 = High on pin stops conversions 99 * 2 = Edge triggered, edge on pin delays conversion by delay param (above) 100 * 3 = Edge triggered, edge on pin starts conversion after delay param 101 */ 102 static int mask; 103 module_param(mask, int, 0); 104 MODULE_PARM_DESC(mask, "Set adc mask function."); 105 106 /* 107 * Coordinate Polling Enable. 108 * 109 * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together 110 * for every poll. 111 */ 112 static int coord; 113 module_param(coord, int, 0); 114 MODULE_PARM_DESC(coord, "Polling coordinate mode"); 115 116 /* 117 * ADC sample delay times in uS 118 */ 119 static const int delay_table[] = { 120 21, /* 1 AC97 Link frames */ 121 42, /* 2 */ 122 84, /* 4 */ 123 167, /* 8 */ 124 333, /* 16 */ 125 667, /* 32 */ 126 1000, /* 48 */ 127 1333, /* 64 */ 128 2000, /* 96 */ 129 2667, /* 128 */ 130 3333, /* 160 */ 131 4000, /* 192 */ 132 4667, /* 224 */ 133 5333, /* 256 */ 134 6000, /* 288 */ 135 0 /* No delay, switch matrix always on */ 136 }; 137 138 /* 139 * Delay after issuing a POLL command. 140 * 141 * The delay is 3 AC97 link frames + the touchpanel settling delay 142 */ 143 static inline void poll_delay(int d) 144 { 145 udelay(3 * AC97_LINK_FRAME + delay_table[d]); 146 } 147 148 /* 149 * set up the physical settings of the WM9712 150 */ 151 static void wm9712_phy_init(struct wm97xx *wm) 152 { 153 u16 dig1 = 0; 154 u16 dig2 = WM97XX_RPR | WM9712_RPU(1); 155 156 /* WM9712 rpu */ 157 if (rpu) { 158 dig2 &= 0xffc0; 159 dig2 |= WM9712_RPU(rpu); 160 dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms\n", 161 64000 / rpu); 162 } 163 164 /* WM9712 five wire */ 165 if (five_wire) { 166 dig2 |= WM9712_45W; 167 dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n"); 168 169 if (pil) { 170 dev_warn(wm->dev, "pressure measurement is not " 171 "supported in 5-wire mode\n"); 172 pil = 0; 173 } 174 } 175 176 /* touchpanel pressure current*/ 177 if (pil == 2) { 178 dig2 |= WM9712_PIL; 179 dev_dbg(wm->dev, 180 "setting pressure measurement current to 400uA.\n"); 181 } else if (pil) 182 dev_dbg(wm->dev, 183 "setting pressure measurement current to 200uA.\n"); 184 if (!pil) 185 pressure = 0; 186 187 /* polling mode sample settling delay */ 188 if (delay < 0 || delay > 15) { 189 dev_dbg(wm->dev, "supplied delay out of range.\n"); 190 delay = 4; 191 } 192 dig1 &= 0xff0f; 193 dig1 |= WM97XX_DELAY(delay); 194 dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n", 195 delay_table[delay]); 196 197 /* mask */ 198 dig2 |= ((mask & 0x3) << 6); 199 if (mask) { 200 u16 reg; 201 /* Set GPIO4 as Mask Pin*/ 202 reg = wm97xx_reg_read(wm, AC97_MISC_AFE); 203 wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4); 204 reg = wm97xx_reg_read(wm, AC97_GPIO_CFG); 205 wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4); 206 } 207 208 /* wait - coord mode */ 209 if (coord) 210 dig2 |= WM9712_WAIT; 211 212 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1); 213 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2); 214 } 215 216 static void wm9712_dig_enable(struct wm97xx *wm, int enable) 217 { 218 u16 dig2 = wm->dig[2]; 219 220 if (enable) { 221 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, 222 dig2 | WM97XX_PRP_DET_DIG); 223 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */ 224 } else 225 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, 226 dig2 & ~WM97XX_PRP_DET_DIG); 227 } 228 229 static void wm9712_aux_prepare(struct wm97xx *wm) 230 { 231 memcpy(wm->dig_save, wm->dig, sizeof(wm->dig)); 232 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0); 233 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG); 234 } 235 236 static void wm9712_dig_restore(struct wm97xx *wm) 237 { 238 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]); 239 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]); 240 } 241 242 static inline int is_pden(struct wm97xx *wm) 243 { 244 return wm->dig[2] & WM9712_PDEN; 245 } 246 247 /* 248 * Read a sample from the WM9712 adc in polling mode. 249 */ 250 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample) 251 { 252 int timeout = 5 * delay; 253 bool wants_pen = adcsel & WM97XX_PEN_DOWN; 254 255 if (wants_pen && !wm->pen_probably_down) { 256 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 257 if (!(data & WM97XX_PEN_DOWN)) 258 return RC_PENUP; 259 wm->pen_probably_down = 1; 260 } 261 262 /* set up digitiser */ 263 if (wm->mach_ops && wm->mach_ops->pre_sample) 264 wm->mach_ops->pre_sample(adcsel); 265 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK) 266 | WM97XX_POLL | WM97XX_DELAY(delay)); 267 268 /* wait 3 AC97 time slots + delay for conversion */ 269 poll_delay(delay); 270 271 /* wait for POLL to go low */ 272 while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL) 273 && timeout) { 274 udelay(AC97_LINK_FRAME); 275 timeout--; 276 } 277 278 if (timeout <= 0) { 279 /* If PDEN is set, we can get a timeout when pen goes up */ 280 if (is_pden(wm)) 281 wm->pen_probably_down = 0; 282 else 283 dev_dbg(wm->dev, "adc sample timeout\n"); 284 return RC_PENUP; 285 } 286 287 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 288 if (wm->mach_ops && wm->mach_ops->post_sample) 289 wm->mach_ops->post_sample(adcsel); 290 291 /* check we have correct sample */ 292 if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) { 293 dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x\n", 294 adcsel & WM97XX_ADCSEL_MASK, 295 *sample & WM97XX_ADCSEL_MASK); 296 return RC_AGAIN; 297 } 298 299 if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) { 300 /* Sometimes it reads a wrong value the first time. */ 301 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 302 if (!(*sample & WM97XX_PEN_DOWN)) { 303 wm->pen_probably_down = 0; 304 return RC_PENUP; 305 } 306 } 307 308 return RC_VALID; 309 } 310 311 /* 312 * Read a coord from the WM9712 adc in polling mode. 313 */ 314 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data) 315 { 316 int timeout = 5 * delay; 317 318 if (!wm->pen_probably_down) { 319 u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 320 if (!(data_rd & WM97XX_PEN_DOWN)) 321 return RC_PENUP; 322 wm->pen_probably_down = 1; 323 } 324 325 /* set up digitiser */ 326 if (wm->mach_ops && wm->mach_ops->pre_sample) 327 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y); 328 329 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 330 WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay)); 331 332 /* wait 3 AC97 time slots + delay for conversion and read x */ 333 poll_delay(delay); 334 data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 335 /* wait for POLL to go low */ 336 while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL) 337 && timeout) { 338 udelay(AC97_LINK_FRAME); 339 timeout--; 340 } 341 342 if (timeout <= 0) { 343 /* If PDEN is set, we can get a timeout when pen goes up */ 344 if (is_pden(wm)) 345 wm->pen_probably_down = 0; 346 else 347 dev_dbg(wm->dev, "adc sample timeout\n"); 348 return RC_PENUP; 349 } 350 351 /* read back y data */ 352 data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 353 if (pil) 354 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 355 else 356 data->p = DEFAULT_PRESSURE; 357 358 if (wm->mach_ops && wm->mach_ops->post_sample) 359 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y); 360 361 /* check we have correct sample */ 362 if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y)) 363 goto err; 364 if (pil && !(data->p & WM97XX_ADCSEL_PRES)) 365 goto err; 366 367 if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) { 368 wm->pen_probably_down = 0; 369 return RC_PENUP; 370 } 371 return RC_VALID; 372 err: 373 return 0; 374 } 375 376 /* 377 * Sample the WM9712 touchscreen in polling mode 378 */ 379 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data) 380 { 381 int rc; 382 383 if (coord) { 384 rc = wm9712_poll_coord(wm, data); 385 if (rc != RC_VALID) 386 return rc; 387 } else { 388 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, 389 &data->x); 390 if (rc != RC_VALID) 391 return rc; 392 393 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, 394 &data->y); 395 if (rc != RC_VALID) 396 return rc; 397 398 if (pil && !five_wire) { 399 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN, 400 &data->p); 401 if (rc != RC_VALID) 402 return rc; 403 } else 404 data->p = DEFAULT_PRESSURE; 405 } 406 return RC_VALID; 407 } 408 409 /* 410 * Enable WM9712 continuous mode, i.e. touch data is streamed across 411 * an AC97 slot 412 */ 413 static int wm9712_acc_enable(struct wm97xx *wm, int enable) 414 { 415 u16 dig1, dig2; 416 int ret = 0; 417 418 dig1 = wm->dig[1]; 419 dig2 = wm->dig[2]; 420 421 if (enable) { 422 /* continuous mode */ 423 if (wm->mach_ops->acc_startup) { 424 ret = wm->mach_ops->acc_startup(wm); 425 if (ret < 0) 426 return ret; 427 } 428 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK | 429 WM97XX_DELAY_MASK | WM97XX_SLT_MASK); 430 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN | 431 WM97XX_DELAY(delay) | 432 WM97XX_SLT(wm->acc_slot) | 433 WM97XX_RATE(wm->acc_rate); 434 if (pil) 435 dig1 |= WM97XX_ADCSEL_PRES; 436 dig2 |= WM9712_PDEN; 437 } else { 438 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN); 439 dig2 &= ~WM9712_PDEN; 440 if (wm->mach_ops->acc_shutdown) 441 wm->mach_ops->acc_shutdown(wm); 442 } 443 444 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1); 445 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2); 446 447 return 0; 448 } 449 450 struct wm97xx_codec_drv wm9712_codec = { 451 .id = WM9712_ID2, 452 .name = "wm9712", 453 .poll_sample = wm9712_poll_sample, 454 .poll_touch = wm9712_poll_touch, 455 .acc_enable = wm9712_acc_enable, 456 .phy_init = wm9712_phy_init, 457 .dig_enable = wm9712_dig_enable, 458 .dig_restore = wm9712_dig_restore, 459 .aux_prepare = wm9712_aux_prepare, 460 }; 461 EXPORT_SYMBOL_GPL(wm9712_codec); 462 463 /* Module information */ 464 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>"); 465 MODULE_DESCRIPTION("WM9712 Touch Screen Driver"); 466 MODULE_LICENSE("GPL"); 467