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