1/* 2 * drivers/input/touchscreen/tsc2007.c 3 * 4 * Copyright (c) 2008 MtekVision Co., Ltd. 5 * Kwangwoo Lee <kwlee@mtekvision.com> 6 * 7 * Using code from: 8 * - ads7846.c 9 * Copyright (c) 2005 David Brownell 10 * Copyright (c) 2006 Nokia Corporation 11 * - corgi_ts.c 12 * Copyright (C) 2004-2005 Richard Purdie 13 * - omap_ts.[hc], ads7846.h, ts_osk.c 14 * Copyright (C) 2002 MontaVista Software 15 * Copyright (C) 2004 Texas Instruments 16 * Copyright (C) 2005 Dirk Behme 17 * 18 * This program is free software; you can redistribute it and/or modify 19 * it under the terms of the GNU General Public License version 2 as 20 * published by the Free Software Foundation. 21 */ 22 23#include <linux/module.h> 24#include <linux/slab.h> 25#include <linux/input.h> 26#include <linux/interrupt.h> 27#include <linux/i2c.h> 28#include <linux/i2c/tsc2007.h> 29 30#define TS_POLL_DELAY 1 /* ms delay between samples */ 31#define TS_POLL_PERIOD 1 /* ms delay between samples */ 32 33#define TSC2007_MEASURE_TEMP0 (0x0 << 4) 34#define TSC2007_MEASURE_AUX (0x2 << 4) 35#define TSC2007_MEASURE_TEMP1 (0x4 << 4) 36#define TSC2007_ACTIVATE_XN (0x8 << 4) 37#define TSC2007_ACTIVATE_YN (0x9 << 4) 38#define TSC2007_ACTIVATE_YP_XN (0xa << 4) 39#define TSC2007_SETUP (0xb << 4) 40#define TSC2007_MEASURE_X (0xc << 4) 41#define TSC2007_MEASURE_Y (0xd << 4) 42#define TSC2007_MEASURE_Z1 (0xe << 4) 43#define TSC2007_MEASURE_Z2 (0xf << 4) 44 45#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2) 46#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2) 47#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2) 48#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2) 49 50#define TSC2007_12BIT (0x0 << 1) 51#define TSC2007_8BIT (0x1 << 1) 52 53#define MAX_12BIT ((1 << 12) - 1) 54 55#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0) 56 57#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y) 58#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1) 59#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2) 60#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X) 61#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN) 62 63struct ts_event { 64 u16 x; 65 u16 y; 66 u16 z1, z2; 67}; 68 69struct tsc2007 { 70 struct input_dev *input; 71 char phys[32]; 72 struct delayed_work work; 73 74 struct i2c_client *client; 75 76 u16 model; 77 u16 x_plate_ohms; 78 79 bool pendown; 80 int irq; 81 82 int (*get_pendown_state)(void); 83 void (*clear_penirq)(void); 84}; 85 86static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) 87{ 88 s32 data; 89 u16 val; 90 91 data = i2c_smbus_read_word_data(tsc->client, cmd); 92 if (data < 0) { 93 dev_err(&tsc->client->dev, "i2c io error: %d\n", data); 94 return data; 95 } 96 97 /* The protocol and raw data format from i2c interface: 98 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P 99 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit]. 100 */ 101 val = swab16(data) >> 4; 102 103 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val); 104 105 return val; 106} 107 108static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) 109{ 110 /* y- still on; turn on only y+ (and ADC) */ 111 tc->y = tsc2007_xfer(tsc, READ_Y); 112 113 /* turn y- off, x+ on, then leave in lowpower */ 114 tc->x = tsc2007_xfer(tsc, READ_X); 115 116 /* turn y+ off, x- on; we'll use formula #1 */ 117 tc->z1 = tsc2007_xfer(tsc, READ_Z1); 118 tc->z2 = tsc2007_xfer(tsc, READ_Z2); 119 120 /* Prepare for next touch reading - power down ADC, enable PENIRQ */ 121 tsc2007_xfer(tsc, PWRDOWN); 122} 123 124static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc) 125{ 126 u32 rt = 0; 127 128 /* range filtering */ 129 if (tc->x == MAX_12BIT) 130 tc->x = 0; 131 132 if (likely(tc->x && tc->z1)) { 133 /* compute touch pressure resistance using equation #1 */ 134 rt = tc->z2 - tc->z1; 135 rt *= tc->x; 136 rt *= tsc->x_plate_ohms; 137 rt /= tc->z1; 138 rt = (rt + 2047) >> 12; 139 } 140 141 return rt; 142} 143 144static void tsc2007_send_up_event(struct tsc2007 *tsc) 145{ 146 struct input_dev *input = tsc->input; 147 148 dev_dbg(&tsc->client->dev, "UP\n"); 149 150 input_report_key(input, BTN_TOUCH, 0); 151 input_report_abs(input, ABS_PRESSURE, 0); 152 input_sync(input); 153} 154 155static void tsc2007_work(struct work_struct *work) 156{ 157 struct tsc2007 *ts = 158 container_of(to_delayed_work(work), struct tsc2007, work); 159 struct ts_event tc; 160 u32 rt; 161 162 /* 163 * NOTE: We can't rely on the pressure to determine the pen down 164 * state, even though this controller has a pressure sensor. 165 * The pressure value can fluctuate for quite a while after 166 * lifting the pen and in some cases may not even settle at the 167 * expected value. 168 * 169 * The only safe way to check for the pen up condition is in the 170 * work function by reading the pen signal state (it's a GPIO 171 * and IRQ). Unfortunately such callback is not always available, 172 * in that case we have rely on the pressure anyway. 173 */ 174 if (ts->get_pendown_state) { 175 if (unlikely(!ts->get_pendown_state())) { 176 tsc2007_send_up_event(ts); 177 ts->pendown = false; 178 goto out; 179 } 180 181 dev_dbg(&ts->client->dev, "pen is still down\n"); 182 } 183 184 tsc2007_read_values(ts, &tc); 185 186 rt = tsc2007_calculate_pressure(ts, &tc); 187 if (rt > MAX_12BIT) { 188 /* 189 * Sample found inconsistent by debouncing or pressure is 190 * beyond the maximum. Don't report it to user space, 191 * repeat at least once more the measurement. 192 */ 193 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); 194 goto out; 195 196 } 197 198 if (rt) { 199 struct input_dev *input = ts->input; 200 201 if (!ts->pendown) { 202 dev_dbg(&ts->client->dev, "DOWN\n"); 203 204 input_report_key(input, BTN_TOUCH, 1); 205 ts->pendown = true; 206 } 207 208 input_report_abs(input, ABS_X, tc.x); 209 input_report_abs(input, ABS_Y, tc.y); 210 input_report_abs(input, ABS_PRESSURE, rt); 211 212 input_sync(input); 213 214 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n", 215 tc.x, tc.y, rt); 216 217 } else if (!ts->get_pendown_state && ts->pendown) { 218 /* 219 * We don't have callback to check pendown state, so we 220 * have to assume that since pressure reported is 0 the 221 * pen was lifted up. 222 */ 223 tsc2007_send_up_event(ts); 224 ts->pendown = false; 225 } 226 227 out: 228 if (ts->pendown) 229 schedule_delayed_work(&ts->work, 230 msecs_to_jiffies(TS_POLL_PERIOD)); 231 else 232 enable_irq(ts->irq); 233} 234 235static irqreturn_t tsc2007_irq(int irq, void *handle) 236{ 237 struct tsc2007 *ts = handle; 238 239 if (!ts->get_pendown_state || likely(ts->get_pendown_state())) { 240 disable_irq_nosync(ts->irq); 241 schedule_delayed_work(&ts->work, 242 msecs_to_jiffies(TS_POLL_DELAY)); 243 } 244 245 if (ts->clear_penirq) 246 ts->clear_penirq(); 247 248 return IRQ_HANDLED; 249} 250 251static void tsc2007_free_irq(struct tsc2007 *ts) 252{ 253 free_irq(ts->irq, ts); 254 if (cancel_delayed_work_sync(&ts->work)) { 255 /* 256 * Work was pending, therefore we need to enable 257 * IRQ here to balance the disable_irq() done in the 258 * interrupt handler. 259 */ 260 enable_irq(ts->irq); 261 } 262} 263 264static int __devinit tsc2007_probe(struct i2c_client *client, 265 const struct i2c_device_id *id) 266{ 267 struct tsc2007 *ts; 268 struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data; 269 struct input_dev *input_dev; 270 int err; 271 272 if (!pdata) { 273 dev_err(&client->dev, "platform data is required!\n"); 274 return -EINVAL; 275 } 276 277 if (!i2c_check_functionality(client->adapter, 278 I2C_FUNC_SMBUS_READ_WORD_DATA)) 279 return -EIO; 280 281 ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL); 282 input_dev = input_allocate_device(); 283 if (!ts || !input_dev) { 284 err = -ENOMEM; 285 goto err_free_mem; 286 } 287 288 ts->client = client; 289 ts->irq = client->irq; 290 ts->input = input_dev; 291 INIT_DELAYED_WORK(&ts->work, tsc2007_work); 292 293 ts->model = pdata->model; 294 ts->x_plate_ohms = pdata->x_plate_ohms; 295 ts->get_pendown_state = pdata->get_pendown_state; 296 ts->clear_penirq = pdata->clear_penirq; 297 298 snprintf(ts->phys, sizeof(ts->phys), 299 "%s/input0", dev_name(&client->dev)); 300 301 input_dev->name = "TSC2007 Touchscreen"; 302 input_dev->phys = ts->phys; 303 input_dev->id.bustype = BUS_I2C; 304 305 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 306 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 307 308 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0); 309 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0); 310 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); 311 312 if (pdata->init_platform_hw) 313 pdata->init_platform_hw(); 314 315 err = request_irq(ts->irq, tsc2007_irq, 0, 316 client->dev.driver->name, ts); 317 if (err < 0) { 318 dev_err(&client->dev, "irq %d busy?\n", ts->irq); 319 goto err_free_mem; 320 } 321 322 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 323 err = tsc2007_xfer(ts, PWRDOWN); 324 if (err < 0) 325 goto err_free_irq; 326 327 err = input_register_device(input_dev); 328 if (err) 329 goto err_free_irq; 330 331 i2c_set_clientdata(client, ts); 332 333 return 0; 334 335 err_free_irq: 336 tsc2007_free_irq(ts); 337 if (pdata->exit_platform_hw) 338 pdata->exit_platform_hw(); 339 err_free_mem: 340 input_free_device(input_dev); 341 kfree(ts); 342 return err; 343} 344 345static int __devexit tsc2007_remove(struct i2c_client *client) 346{ 347 struct tsc2007 *ts = i2c_get_clientdata(client); 348 struct tsc2007_platform_data *pdata = client->dev.platform_data; 349 350 tsc2007_free_irq(ts); 351 352 if (pdata->exit_platform_hw) 353 pdata->exit_platform_hw(); 354 355 input_unregister_device(ts->input); 356 kfree(ts); 357 358 return 0; 359} 360 361static const struct i2c_device_id tsc2007_idtable[] = { 362 { "tsc2007", 0 }, 363 { } 364}; 365 366MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 367 368static struct i2c_driver tsc2007_driver = { 369 .driver = { 370 .owner = THIS_MODULE, 371 .name = "tsc2007" 372 }, 373 .id_table = tsc2007_idtable, 374 .probe = tsc2007_probe, 375 .remove = __devexit_p(tsc2007_remove), 376}; 377 378static int __init tsc2007_init(void) 379{ 380 return i2c_add_driver(&tsc2007_driver); 381} 382 383static void __exit tsc2007_exit(void) 384{ 385 i2c_del_driver(&tsc2007_driver); 386} 387 388module_init(tsc2007_init); 389module_exit(tsc2007_exit); 390 391MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 392MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 393MODULE_LICENSE("GPL"); 394