2 * TSC2301 touchscreen driver
4 * Copyright (C) 2005-2008 Nokia Corporation
6 * Written by Jarkko Oikarinen, Imre Deak and Juha Yrjola
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/delay.h>
29 #include <linux/spi/spi.h>
31 #include <linux/spi/tsc2301.h>
34 * The touchscreen interface operates as follows:
37 * Request access to GPIO103 (DAV)
38 * tsc2301_ts_irq_handler will trigger when DAV line goes down
40 * 1) Pen is pressed against touchscreeen
41 * 2) TSC2301 performs AD conversion
42 * 3) After the conversion is done TSC2301 drives DAV line down
43 * 4) GPIO IRQ is received and tsc2301_ts_irq_handler is called
44 * 5) tsc2301_ts_irq_handler queues up an spi transfer to fetch
45 * the x, y, z1, z2 values
46 * 6) SPI framework calls tsc2301_ts_rx after the coordinates are read
47 * 7) When the penup_timer expires, there have not been DAV interrupts
48 * during the last 20ms which means the pen has been lifted.
52 #define TSC2301_TOUCHSCREEN_PRODUCT_ID 0x0052
53 #define TSC2301_TOUCHSCREEN_PRODUCT_VERSION 0x0001
55 #define TSC2301_TS_PENUP_TIME 20
57 #define TSC2301_ADCREG_CONVERSION_CTRL_BY_TSC2301 0x8000
58 #define TSC2301_ADCREG_CONVERSION_CTRL_BY_HOST 0x0000
60 #define TSC2301_ADCREG_FUNCTION_NONE 0x0000
61 #define TSC2301_ADCREG_FUNCTION_XY 0x0400
62 #define TSC2301_ADCREG_FUNCTION_XYZ 0x0800
63 #define TSC2301_ADCREG_FUNCTION_X 0x0C00
64 #define TSC2301_ADCREG_FUNCTION_Y 0x1000
65 #define TSC2301_ADCREG_FUNCTION_Z 0x1400
66 #define TSC2301_ADCREG_FUNCTION_DAT1 0x1800
67 #define TSC2301_ADCREG_FUNCTION_DAT2 0x1C00
68 #define TSC2301_ADCREG_FUNCTION_AUX1 0x2000
69 #define TSC2301_ADCREG_FUNCTION_AUX2 0x2400
70 #define TSC2301_ADCREG_FUNCTION_TEMP 0x2800
72 #define TSC2301_ADCREG_RESOLUTION_8BIT 0x0100
73 #define TSC2301_ADCREG_RESOLUTION_10BIT 0x0200
74 #define TSC2301_ADCREG_RESOLUTION_12BIT 0x0300
76 #define TSC2301_ADCREG_AVERAGING_NONE 0x0000
77 #define TSC2301_ADCREG_AVERAGING_4AVG 0x0040
78 #define TSC2301_ADCREG_AVERAGING_8AVG 0x0080
79 #define TSC2301_ADCREG_AVERAGING_16AVG 0x00C0
81 #define TSC2301_ADCREG_CLOCK_8MHZ 0x0000
82 #define TSC2301_ADCREG_CLOCK_4MHZ 0x0010
83 #define TSC2301_ADCREG_CLOCK_2MHZ 0x0020
84 #define TSC2301_ADCREG_CLOCK_1MHZ 0x0030
86 #define TSC2301_ADCREG_VOLTAGE_STAB_0US 0x0000
87 #define TSC2301_ADCREG_VOLTAGE_STAB_100US 0x0002
88 #define TSC2301_ADCREG_VOLTAGE_STAB_500US 0x0004
89 #define TSC2301_ADCREG_VOLTAGE_STAB_1MS 0x0006
90 #define TSC2301_ADCREG_VOLTAGE_STAB_5MS 0x0008
91 #define TSC2301_ADCREG_VOLTAGE_STAB_10MS 0x000A
92 #define TSC2301_ADCREG_VOLTAGE_STAB_50MS 0x000C
93 #define TSC2301_ADCREG_VOLTAGE_STAB_100MS 0x000E
95 #define TSC2301_ADCREG_STOP_CONVERSION 0x4000
97 #define MAX_12BIT ((1 << 12) - 1)
99 #define TS_RECT_SIZE 8
100 #define TSF_MIN_Z1 100
101 #define TSF_MAX_Z2 4000
103 #define TSF_SAMPLES 4
122 struct input_dev *idev;
124 struct timer_list penup_timer;
127 struct spi_transfer read_xfer[2];
128 struct spi_message read_msg;
129 struct ts_coords *coords;
131 struct ts_filter filter;
153 static const u16 tsc2301_ts_read_data = 0x8000 | TSC2301_REG_X;
155 static int tsc2301_ts_check_config(struct tsc2301_ts *ts, int *hw_flags)
160 switch (ts->hw_avg_max) {
162 flags |= TSC2301_ADCREG_AVERAGING_NONE;
165 flags |= TSC2301_ADCREG_AVERAGING_4AVG;
168 flags |= TSC2301_ADCREG_AVERAGING_8AVG;
171 flags |= TSC2301_ADCREG_AVERAGING_16AVG;
177 switch (ts->stab_time) {
179 flags |= TSC2301_ADCREG_VOLTAGE_STAB_0US;
182 flags |= TSC2301_ADCREG_VOLTAGE_STAB_100US;
185 flags |= TSC2301_ADCREG_VOLTAGE_STAB_500US;
188 flags |= TSC2301_ADCREG_VOLTAGE_STAB_1MS;
191 flags |= TSC2301_ADCREG_VOLTAGE_STAB_5MS;
194 flags |= TSC2301_ADCREG_VOLTAGE_STAB_10MS;
197 flags |= TSC2301_ADCREG_VOLTAGE_STAB_50MS;
200 flags |= TSC2301_ADCREG_VOLTAGE_STAB_100MS;
211 * This odd three-time initialization is to work around a bug in TSC2301.
212 * See TSC2301 errata for details.
214 static int tsc2301_ts_configure(struct tsc2301 *tsc, int flags)
216 struct spi_transfer xfer[5];
217 struct spi_transfer *x;
218 struct spi_message m;
220 u16 val1, val2, val3;
223 val1 = TSC2301_ADCREG_CONVERSION_CTRL_BY_HOST |
224 TSC2301_ADCREG_STOP_CONVERSION |
225 TSC2301_ADCREG_FUNCTION_NONE |
226 TSC2301_ADCREG_RESOLUTION_12BIT |
227 TSC2301_ADCREG_AVERAGING_NONE |
228 TSC2301_ADCREG_CLOCK_2MHZ |
229 TSC2301_ADCREG_VOLTAGE_STAB_100MS;
231 val2 = TSC2301_ADCREG_CONVERSION_CTRL_BY_HOST |
232 TSC2301_ADCREG_FUNCTION_XYZ |
233 TSC2301_ADCREG_RESOLUTION_12BIT |
234 TSC2301_ADCREG_AVERAGING_16AVG |
235 TSC2301_ADCREG_CLOCK_1MHZ |
236 TSC2301_ADCREG_VOLTAGE_STAB_100MS;
238 /* Averaging and voltage stabilization settings in flags */
239 val3 = TSC2301_ADCREG_CONVERSION_CTRL_BY_TSC2301 |
240 TSC2301_ADCREG_FUNCTION_XYZ |
241 TSC2301_ADCREG_RESOLUTION_12BIT |
242 TSC2301_ADCREG_CLOCK_2MHZ |
245 /* Now we prepare the command for transferring */
246 data[0] = TSC2301_REG_ADC;
248 data[2] = TSC2301_REG_ADC;
250 data[4] = TSC2301_REG_ADC;
252 data[6] = TSC2301_REG_REF;
253 data[7] = 1 << 4 | 1 << 2 | 1; /* intref, 100uS settl, 2.5V ref */
254 data[8] = TSC2301_REG_CONFIG;
255 data[9] = 3 << 3 | 2 << 0; /* 340uS pre-chrg, 544us delay */
257 spi_message_init(&m);
260 memset(xfer, 0, sizeof(xfer));
263 for (i = 0; i < 10; i += 2) {
264 x->tx_buf = &data[i];
268 spi_message_add_tail(x, &m);
276 static void tsc2301_ts_start_scan(struct tsc2301 *tsc)
278 tsc2301_ts_configure(tsc, tsc->ts->hw_flags);
279 tsc2301_kp_restart(tsc);
282 static void tsc2301_ts_stop_scan(struct tsc2301 *tsc)
284 tsc2301_write_reg(tsc, TSC2301_REG_ADC, TSC2301_ADCREG_STOP_CONVERSION);
285 tsc2301_kp_restart(tsc);
288 static void update_pen_state(struct tsc2301_ts *ts, int x, int y, int pressure)
291 input_report_abs(ts->idev, ABS_X, x);
292 input_report_abs(ts->idev, ABS_Y, y);
293 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
295 input_report_key(ts->idev, BTN_TOUCH, 1);
298 input_report_abs(ts->idev, ABS_PRESSURE, 0);
300 input_report_key(ts->idev, BTN_TOUCH, 0);
304 input_sync(ts->idev);
307 dev_dbg(&tsc->spi->dev, "x %4d y %4d p %4d\n", x, y, pressure);
311 static int filter(struct tsc2301_ts *ts, int x, int y, int z1, int z2)
313 int inside_rect, pressure_limit, Rt;
314 struct ts_filter *tsf = &ts->filter;
316 /* validate pressure and position */
317 if (x > MAX_12BIT || y > MAX_12BIT)
320 /* skip coords if the pressure-components are out of range */
321 if (z1 < TSF_MIN_Z1 || z2 > TSF_MAX_Z2)
324 /* Use the x,y,z1,z2 directly on the first "pen down" event */
325 if (ts->event_sent) {
331 if (++tsf->sample_cnt < TSF_SAMPLES)
333 x = tsf->avg_x / TSF_SAMPLES;
334 y = tsf->avg_y / TSF_SAMPLES;
335 z1 = tsf->avg_z1 / TSF_SAMPLES;
336 z2 = tsf->avg_z2 / TSF_SAMPLES;
344 pressure_limit = ts->event_sent? ts->max_pressure: ts->touch_pressure;
346 /* z1 is always at least 100: */
347 Rt = x * (z2 - z1) / z1;
348 Rt = Rt * ts->x_plate_ohm / 4096;
349 if (Rt > pressure_limit)
352 /* discard the event if it still is within the previous rect - unless
353 * if the pressure is harder, but then use previous x,y position */
355 x > (int)ts->x - TS_RECT_SIZE && x < (int)ts->x + TS_RECT_SIZE &&
356 y > (int)ts->y - TS_RECT_SIZE && y < (int)ts->y + TS_RECT_SIZE);
358 if (!ts->event_sent || !inside_rect) {
363 } else if (Rt < ts->p) {
371 * This procedure is called by the SPI framework after the coordinates
372 * have been read from TSC2301
374 static void tsc2301_ts_rx(void *arg)
376 struct tsc2301 *tsc = arg;
377 struct tsc2301_ts *ts = tsc->ts;
386 send_event = filter(ts, x, y, z1, z2);
388 update_pen_state(ts, ts->x, ts->y, ts->p);
392 mod_timer(&ts->penup_timer,
393 jiffies + msecs_to_jiffies(TSC2301_TS_PENUP_TIME));
397 * Timer is called TSC2301_TS_PENUP_TIME after pen is up
399 static void tsc2301_ts_timer_handler(unsigned long data)
401 struct tsc2301 *tsc = (struct tsc2301 *)data;
402 struct tsc2301_ts *ts = tsc->ts;
404 if (ts->event_sent) {
406 update_pen_state(ts, 0, 0, 0);
411 * This interrupt is called when pen is down and coordinates are
412 * available. That is indicated by a falling edge on DEV line.
414 static irqreturn_t tsc2301_ts_irq_handler(int irq, void *dev_id)
416 struct tsc2301 *tsc = dev_id;
417 struct tsc2301_ts *ts = tsc->ts;
420 r = spi_async(tsc->spi, &ts->read_msg);
422 dev_err(&tsc->spi->dev, "ts: spi_async() failed");
424 mod_timer(&ts->penup_timer,
425 jiffies + msecs_to_jiffies(TSC2301_TS_PENUP_TIME));
430 static void tsc2301_ts_disable(struct tsc2301 *tsc)
432 struct tsc2301_ts *ts = tsc->ts;
434 if (ts->disable_depth++ != 0)
437 disable_irq(ts->irq);
439 /* wait until penup timer expire normally */
442 } while (ts->event_sent);
444 tsc2301_ts_stop_scan(tsc);
447 static void tsc2301_ts_enable(struct tsc2301 *tsc)
449 struct tsc2301_ts *ts = tsc->ts;
451 if (--ts->disable_depth != 0)
456 tsc2301_ts_start_scan(tsc);
460 int tsc2301_ts_suspend(struct tsc2301 *tsc)
462 struct tsc2301_ts *ts = tsc->ts;
464 mutex_lock(&ts->mutex);
465 tsc2301_ts_disable(tsc);
466 mutex_unlock(&ts->mutex);
471 void tsc2301_ts_resume(struct tsc2301 *tsc)
473 struct tsc2301_ts *ts = tsc->ts;
475 mutex_lock(&ts->mutex);
476 tsc2301_ts_enable(tsc);
477 mutex_unlock(&ts->mutex);
481 static void tsc2301_ts_setup_spi_xfer(struct tsc2301 *tsc)
483 struct tsc2301_ts *ts = tsc->ts;
484 struct spi_message *m = &ts->read_msg;
485 struct spi_transfer *x = &ts->read_xfer[0];
489 x->tx_buf = &tsc2301_ts_read_data;
491 spi_message_add_tail(x, m);
494 x->rx_buf = ts->coords;
496 spi_message_add_tail(x, m);
498 m->complete = tsc2301_ts_rx;
502 static ssize_t tsc2301_ts_pen_down_show(struct device *dev,
503 struct device_attribute *attr,
506 struct tsc2301 *tsc = dev_get_drvdata(dev);
508 return sprintf(buf, "%u\n", tsc->ts->pen_down);
511 static DEVICE_ATTR(pen_down, S_IRUGO, tsc2301_ts_pen_down_show, NULL);
513 static ssize_t tsc2301_ts_disable_show(struct device *dev,
514 struct device_attribute *attr, char *buf)
516 struct tsc2301 *tsc = dev_get_drvdata(dev);
517 struct tsc2301_ts *ts = tsc->ts;
519 return sprintf(buf, "%u\n", ts->disabled);
522 static ssize_t tsc2301_ts_disable_store(struct device *dev,
523 struct device_attribute *attr,
524 const char *buf, size_t count)
526 struct tsc2301 *tsc = dev_get_drvdata(dev);
527 struct tsc2301_ts *ts = tsc->ts;
531 i = simple_strtoul(buf, &endp, 10);
533 mutex_lock(&ts->mutex);
534 if (i == ts->disabled) goto out;
538 tsc2301_ts_disable(tsc);
540 tsc2301_ts_enable(tsc);
542 mutex_unlock(&ts->mutex);
546 static DEVICE_ATTR(disable_ts, 0664, tsc2301_ts_disable_show,
547 tsc2301_ts_disable_store);
549 int __devinit tsc2301_ts_init(struct tsc2301 *tsc,
550 struct tsc2301_platform_data *pdata)
552 struct tsc2301_ts *ts;
553 struct input_dev *idev;
556 int x_fudge, y_fudge, p_fudge;
558 if (pdata->dav_int <= 0) {
559 dev_err(&tsc->spi->dev, "need DAV IRQ");
563 ts = kzalloc(sizeof(*ts), GFP_KERNEL);
568 ts->coords = kzalloc(sizeof(*ts->coords), GFP_KERNEL);
569 if (ts->coords == NULL) {
574 ts->irq = pdata->dav_int;
576 init_timer(&ts->penup_timer);
577 setup_timer(&ts->penup_timer, tsc2301_ts_timer_handler,
580 mutex_init(&ts->mutex);
582 ts->x_plate_ohm = pdata->ts_x_plate_ohm ? : 280;
583 ts->hw_avg_max = pdata->ts_hw_avg;
584 ts->max_pressure = pdata->ts_max_pressure ? : MAX_12BIT;
585 ts->touch_pressure = pdata->ts_touch_pressure ? : ts->max_pressure;
586 ts->stab_time = pdata->ts_stab_time;
588 x_max = pdata->ts_x_max ? : 4096;
589 y_max = pdata->ts_y_max ? : 4096;
590 x_fudge = pdata->ts_x_fudge ? : 4;
591 y_fudge = pdata->ts_y_fudge ? : 8;
592 p_fudge = pdata->ts_pressure_fudge ? : 2;
594 if ((r = tsc2301_ts_check_config(ts, &ts->hw_flags))) {
595 dev_err(&tsc->spi->dev, "invalid configuration\n");
599 idev = input_allocate_device();
604 idev->name = "TSC2301 touchscreen";
605 snprintf(ts->phys, sizeof(ts->phys),
606 "%s/input-ts", tsc->spi->dev.bus_id);
607 idev->phys = ts->phys;
608 idev->dev.parent = &tsc->spi->dev;
610 idev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
611 idev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
614 tsc2301_ts_setup_spi_xfer(tsc);
616 /* These parameters should perhaps be configurable? */
617 input_set_abs_params(idev, ABS_X, 0, x_max, x_fudge, 0);
618 input_set_abs_params(idev, ABS_Y, 0, y_max, y_fudge, 0);
619 input_set_abs_params(idev, ABS_PRESSURE, 0, ts->max_pressure,
622 tsc2301_ts_start_scan(tsc);
624 r = request_irq(ts->irq, tsc2301_ts_irq_handler,
625 IRQF_SAMPLE_RANDOM | IRQF_TRIGGER_FALLING,
628 dev_err(&tsc->spi->dev, "unable to get DAV IRQ");
631 set_irq_wake(ts->irq, 1);
633 if (device_create_file(&tsc->spi->dev, &dev_attr_pen_down) < 0)
635 if (device_create_file(&tsc->spi->dev, &dev_attr_disable_ts) < 0)
638 r = input_register_device(idev);
640 dev_err(&tsc->spi->dev, "can't register touchscreen device\n");
646 device_remove_file(&tsc->spi->dev, &dev_attr_disable_ts);
648 device_remove_file(&tsc->spi->dev, &dev_attr_pen_down);
650 free_irq(ts->irq, tsc);
652 tsc2301_ts_stop_scan(tsc);
653 input_free_device(idev);
660 void __devexit tsc2301_ts_exit(struct tsc2301 *tsc)
662 struct tsc2301_ts *ts = tsc->ts;
664 tsc2301_ts_disable(tsc);
666 device_remove_file(&tsc->spi->dev, &dev_attr_disable_ts);
667 device_remove_file(&tsc->spi->dev, &dev_attr_pen_down);
669 free_irq(ts->irq, tsc);
670 input_unregister_device(ts->idev);
675 MODULE_AUTHOR("Jarkko Oikarinen <jarkko.oikarinen@nokia.com>");
676 MODULE_LICENSE("GPL");