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 */ 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 */ 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 } 177 178 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 } 188 189 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 } 195 196 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 } 201 202 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 */ 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 */ 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 */ 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