1 /* 2 * wm9705.c -- Codec driver for Wolfson WM9705 AC97 Codec. 3 * 4 * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC. 5 * Author: Liam Girdwood 6 * liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com 7 * Parts Copyright : Ian Molton <spyro@f2s.com> 8 * Andrew Zabolotny <zap@homelink.ru> 9 * Russell King <rmk@arm.linux.org.uk> 10 * 11 * This program is free software; you can redistribute it and/or modify it 12 * under the terms of the GNU General Public License as published by the 13 * Free Software Foundation; either version 2 of the License, or (at your 14 * option) any later version. 15 * 16 */ 17 18 #include <linux/module.h> 19 #include <linux/moduleparam.h> 20 #include <linux/version.h> 21 #include <linux/kernel.h> 22 #include <linux/input.h> 23 #include <linux/delay.h> 24 #include <linux/bitops.h> 25 #include <linux/wm97xx.h> 26 27 #define TS_NAME "wm97xx" 28 #define WM9705_VERSION "1.00" 29 #define DEFAULT_PRESSURE 0xb0c0 30 31 /* 32 * Module parameters 33 */ 34 35 /* 36 * Set current used for pressure measurement. 37 * 38 * Set pil = 2 to use 400uA 39 * pil = 1 to use 200uA and 40 * pil = 0 to disable pressure measurement. 41 * 42 * This is used to increase the range of values returned by the adc 43 * when measureing touchpanel pressure. 44 */ 45 static int pil; 46 module_param(pil, int, 0); 47 MODULE_PARM_DESC(pil, "Set current used for pressure measurement."); 48 49 /* 50 * Set threshold for pressure measurement. 51 * 52 * Pen down pressure below threshold is ignored. 53 */ 54 static int pressure = DEFAULT_PRESSURE & 0xfff; 55 module_param(pressure, int, 0); 56 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement."); 57 58 /* 59 * Set adc sample delay. 60 * 61 * For accurate touchpanel measurements, some settling time may be 62 * required between the switch matrix applying a voltage across the 63 * touchpanel plate and the ADC sampling the signal. 64 * 65 * This delay can be set by setting delay = n, where n is the array 66 * position of the delay in the array delay_table below. 67 * Long delays > 1ms are supported for completeness, but are not 68 * recommended. 69 */ 70 static int delay = 4; 71 module_param(delay, int, 0); 72 MODULE_PARM_DESC(delay, "Set adc sample delay."); 73 74 /* 75 * Pen detect comparator threshold. 76 * 77 * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold 78 * i.e. 1 = Vmid/15 threshold 79 * 15 = Vmid/1 threshold 80 * 81 * Adjust this value if you are having problems with pen detect not 82 * detecting any down events. 83 */ 84 static int pdd = 8; 85 module_param(pdd, int, 0); 86 MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold"); 87 88 /* 89 * Set adc mask function. 90 * 91 * Sources of glitch noise, such as signals driving an LCD display, may feed 92 * through to the touch screen plates and affect measurement accuracy. In 93 * order to minimise this, a signal may be applied to the MASK pin to delay or 94 * synchronise the sampling. 95 * 96 * 0 = No delay or sync 97 * 1 = High on pin stops conversions 98 * 2 = Edge triggered, edge on pin delays conversion by delay param (above) 99 * 3 = Edge triggered, edge on pin starts conversion after delay param 100 */ 101 static int mask; 102 module_param(mask, int, 0); 103 MODULE_PARM_DESC(mask, "Set adc mask function."); 104 105 /* 106 * ADC sample delay times in uS 107 */ 108 static const int delay_table[] = { 109 21, /* 1 AC97 Link frames */ 110 42, /* 2 */ 111 84, /* 4 */ 112 167, /* 8 */ 113 333, /* 16 */ 114 667, /* 32 */ 115 1000, /* 48 */ 116 1333, /* 64 */ 117 2000, /* 96 */ 118 2667, /* 128 */ 119 3333, /* 160 */ 120 4000, /* 192 */ 121 4667, /* 224 */ 122 5333, /* 256 */ 123 6000, /* 288 */ 124 0 /* No delay, switch matrix always on */ 125 }; 126 127 /* 128 * Delay after issuing a POLL command. 129 * 130 * The delay is 3 AC97 link frames + the touchpanel settling delay 131 */ 132 static inline void poll_delay(int d) 133 { 134 udelay(3 * AC97_LINK_FRAME + delay_table[d]); 135 } 136 137 /* 138 * set up the physical settings of the WM9705 139 */ 140 static void wm9705_phy_init(struct wm97xx *wm) 141 { 142 u16 dig1 = 0, dig2 = WM97XX_RPR; 143 144 /* 145 * mute VIDEO and AUX as they share X and Y touchscreen 146 * inputs on the WM9705 147 */ 148 wm97xx_reg_write(wm, AC97_AUX, 0x8000); 149 wm97xx_reg_write(wm, AC97_VIDEO, 0x8000); 150 151 /* touchpanel pressure current*/ 152 if (pil == 2) { 153 dig2 |= WM9705_PIL; 154 dev_dbg(wm->dev, 155 "setting pressure measurement current to 400uA."); 156 } else if (pil) 157 dev_dbg(wm->dev, 158 "setting pressure measurement current to 200uA."); 159 if (!pil) 160 pressure = 0; 161 162 /* polling mode sample settling delay */ 163 if (delay != 4) { 164 if (delay < 0 || delay > 15) { 165 dev_dbg(wm->dev, "supplied delay out of range."); 166 delay = 4; 167 } 168 } 169 dig1 &= 0xff0f; 170 dig1 |= WM97XX_DELAY(delay); 171 dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.", 172 delay_table[delay]); 173 174 /* WM9705 pdd */ 175 dig2 |= (pdd & 0x000f); 176 dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f)); 177 178 /* mask */ 179 dig2 |= ((mask & 0x3) << 4); 180 181 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1); 182 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2); 183 } 184 185 static void wm9705_dig_enable(struct wm97xx *wm, int enable) 186 { 187 if (enable) { 188 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, 189 wm->dig[2] | WM97XX_PRP_DET_DIG); 190 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */ 191 } else 192 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, 193 wm->dig[2] & ~WM97XX_PRP_DET_DIG); 194 } 195 196 static void wm9705_aux_prepare(struct wm97xx *wm) 197 { 198 memcpy(wm->dig_save, wm->dig, sizeof(wm->dig)); 199 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0); 200 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG); 201 } 202 203 static void wm9705_dig_restore(struct wm97xx *wm) 204 { 205 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]); 206 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]); 207 } 208 209 static inline int is_pden(struct wm97xx *wm) 210 { 211 return wm->dig[2] & WM9705_PDEN; 212 } 213 214 /* 215 * Read a sample from the WM9705 adc in polling mode. 216 */ 217 static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample) 218 { 219 int timeout = 5 * delay; 220 221 if (!wm->pen_probably_down) { 222 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 223 if (!(data & WM97XX_PEN_DOWN)) 224 return RC_PENUP; 225 wm->pen_probably_down = 1; 226 } 227 228 /* set up digitiser */ 229 if (adcsel & 0x8000) 230 adcsel = ((adcsel & 0x7fff) + 3) << 12; 231 232 if (wm->mach_ops && wm->mach_ops->pre_sample) 233 wm->mach_ops->pre_sample(adcsel); 234 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 235 adcsel | WM97XX_POLL | WM97XX_DELAY(delay)); 236 237 /* wait 3 AC97 time slots + delay for conversion */ 238 poll_delay(delay); 239 240 /* wait for POLL to go low */ 241 while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL) 242 && timeout) { 243 udelay(AC97_LINK_FRAME); 244 timeout--; 245 } 246 247 if (timeout == 0) { 248 /* If PDEN is set, we can get a timeout when pen goes up */ 249 if (is_pden(wm)) 250 wm->pen_probably_down = 0; 251 else 252 dev_dbg(wm->dev, "adc sample timeout"); 253 return RC_PENUP; 254 } 255 256 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); 257 if (wm->mach_ops && wm->mach_ops->post_sample) 258 wm->mach_ops->post_sample(adcsel); 259 260 /* check we have correct sample */ 261 if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) { 262 dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel, 263 *sample & WM97XX_ADCSEL_MASK); 264 return RC_PENUP; 265 } 266 267 if (!(*sample & WM97XX_PEN_DOWN)) { 268 wm->pen_probably_down = 0; 269 return RC_PENUP; 270 } 271 272 return RC_VALID; 273 } 274 275 /* 276 * Sample the WM9705 touchscreen in polling mode 277 */ 278 static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data) 279 { 280 int rc; 281 282 rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X, &data->x); 283 if (rc != RC_VALID) 284 return rc; 285 rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y); 286 if (rc != RC_VALID) 287 return rc; 288 if (pil) { 289 rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES, &data->p); 290 if (rc != RC_VALID) 291 return rc; 292 } else 293 data->p = DEFAULT_PRESSURE; 294 295 return RC_VALID; 296 } 297 298 /* 299 * Enable WM9705 continuous mode, i.e. touch data is streamed across 300 * an AC97 slot 301 */ 302 static int wm9705_acc_enable(struct wm97xx *wm, int enable) 303 { 304 u16 dig1, dig2; 305 int ret = 0; 306 307 dig1 = wm->dig[1]; 308 dig2 = wm->dig[2]; 309 310 if (enable) { 311 /* continous mode */ 312 if (wm->mach_ops->acc_startup && 313 (ret = wm->mach_ops->acc_startup(wm)) < 0) 314 return ret; 315 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK | 316 WM97XX_DELAY_MASK | WM97XX_SLT_MASK); 317 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN | 318 WM97XX_DELAY(delay) | 319 WM97XX_SLT(wm->acc_slot) | 320 WM97XX_RATE(wm->acc_rate); 321 if (pil) 322 dig1 |= WM97XX_ADCSEL_PRES; 323 dig2 |= WM9705_PDEN; 324 } else { 325 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN); 326 dig2 &= ~WM9705_PDEN; 327 if (wm->mach_ops->acc_shutdown) 328 wm->mach_ops->acc_shutdown(wm); 329 } 330 331 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1); 332 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2); 333 334 return ret; 335 } 336 337 struct wm97xx_codec_drv wm9705_codec = { 338 .id = WM9705_ID2, 339 .name = "wm9705", 340 .poll_sample = wm9705_poll_sample, 341 .poll_touch = wm9705_poll_touch, 342 .acc_enable = wm9705_acc_enable, 343 .phy_init = wm9705_phy_init, 344 .dig_enable = wm9705_dig_enable, 345 .dig_restore = wm9705_dig_restore, 346 .aux_prepare = wm9705_aux_prepare, 347 }; 348 EXPORT_SYMBOL_GPL(wm9705_codec); 349 350 /* Module information */ 351 MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>"); 352 MODULE_DESCRIPTION("WM9705 Touch Screen Driver"); 353 MODULE_LICENSE("GPL"); 354