2 * drivers/input/touchscreen/tsc2007.c
4 * Copyright (c) 2008 MtekVision Co., Ltd.
5 * Kwangwoo Lee <kwlee@mtekvision.com>
9 * Copyright (c) 2005 David Brownell
10 * Copyright (c) 2006 Nokia Corporation
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
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.
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>
30 #define TS_POLL_DELAY 1 /* ms delay between samples */
31 #define TS_POLL_PERIOD 1 /* ms delay between samples */
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)
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)
50 #define TSC2007_12BIT (0x0 << 1)
51 #define TSC2007_8BIT (0x1 << 1)
53 #define MAX_12BIT ((1 << 12) - 1)
55 #define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
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)
70 struct input_dev *input;
72 struct delayed_work work;
74 struct i2c_client *client;
82 int (*get_pendown_state)(void);
83 void (*clear_penirq)(void);
86 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
91 data = i2c_smbus_read_word_data(tsc->client, cmd);
93 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
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].
101 val = swab16(data) >> 4;
103 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
108 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
110 /* y- still on; turn on only y+ (and ADC) */
111 tc->y = tsc2007_xfer(tsc, READ_Y);
113 /* turn y- off, x+ on, then leave in lowpower */
114 tc->x = tsc2007_xfer(tsc, READ_X);
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);
120 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
121 tsc2007_xfer(tsc, PWRDOWN);
124 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
128 /* range filtering */
129 if (tc->x == MAX_12BIT)
132 if (likely(tc->x && tc->z1)) {
133 /* compute touch pressure resistance using equation #1 */
134 rt = tc->z2 - tc->z1;
136 rt *= tsc->x_plate_ohms;
138 rt = (rt + 2047) >> 12;
144 static void tsc2007_send_up_event(struct tsc2007 *tsc)
146 struct input_dev *input = tsc->input;
148 dev_dbg(&tsc->client->dev, "UP\n");
150 input_report_key(input, BTN_TOUCH, 0);
151 input_report_abs(input, ABS_PRESSURE, 0);
155 static void tsc2007_work(struct work_struct *work)
158 container_of(to_delayed_work(work), struct tsc2007, work);
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
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.
174 if (ts->get_pendown_state) {
175 if (unlikely(!ts->get_pendown_state())) {
176 tsc2007_send_up_event(ts);
181 dev_dbg(&ts->client->dev, "pen is still down\n");
184 tsc2007_read_values(ts, &tc);
186 rt = tsc2007_calculate_pressure(ts, &tc);
187 if (rt > MAX_12BIT) {
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.
193 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
199 struct input_dev *input = ts->input;
202 dev_dbg(&ts->client->dev, "DOWN\n");
204 input_report_key(input, BTN_TOUCH, 1);
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);
214 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
217 } else if (!ts->get_pendown_state && ts->pendown) {
219 * We don't have callback to check pendown state, so we
220 * have to assume that since pressure reported is 0 the
223 tsc2007_send_up_event(ts);
229 schedule_delayed_work(&ts->work,
230 msecs_to_jiffies(TS_POLL_PERIOD));
235 static irqreturn_t tsc2007_irq(int irq, void *handle)
237 struct tsc2007 *ts = handle;
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));
245 if (ts->clear_penirq)
251 static void tsc2007_free_irq(struct tsc2007 *ts)
253 free_irq(ts->irq, ts);
254 if (cancel_delayed_work_sync(&ts->work)) {
256 * Work was pending, therefore we need to enable
257 * IRQ here to balance the disable_irq() done in the
264 static int __devinit tsc2007_probe(struct i2c_client *client,
265 const struct i2c_device_id *id)
268 struct tsc2007_platform_data *pdata = client->dev.platform_data;
269 struct input_dev *input_dev;
273 dev_err(&client->dev, "platform data is required!\n");
277 if (!i2c_check_functionality(client->adapter,
278 I2C_FUNC_SMBUS_READ_WORD_DATA))
281 ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
282 input_dev = input_allocate_device();
283 if (!ts || !input_dev) {
289 ts->irq = client->irq;
290 ts->input = input_dev;
291 INIT_DELAYED_WORK(&ts->work, tsc2007_work);
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;
298 snprintf(ts->phys, sizeof(ts->phys),
299 "%s/input0", dev_name(&client->dev));
301 input_dev->name = "TSC2007 Touchscreen";
302 input_dev->phys = ts->phys;
303 input_dev->id.bustype = BUS_I2C;
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);
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);
312 if (pdata->init_platform_hw)
313 pdata->init_platform_hw();
315 err = request_irq(ts->irq, tsc2007_irq, 0,
316 client->dev.driver->name, ts);
318 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
322 /* Prepare for touch readings - power down ADC and enable PENIRQ */
323 err = tsc2007_xfer(ts, PWRDOWN);
327 err = input_register_device(input_dev);
331 i2c_set_clientdata(client, ts);
336 tsc2007_free_irq(ts);
337 if (pdata->exit_platform_hw)
338 pdata->exit_platform_hw();
340 input_free_device(input_dev);
345 static int __devexit tsc2007_remove(struct i2c_client *client)
347 struct tsc2007 *ts = i2c_get_clientdata(client);
348 struct tsc2007_platform_data *pdata = client->dev.platform_data;
350 tsc2007_free_irq(ts);
352 if (pdata->exit_platform_hw)
353 pdata->exit_platform_hw();
355 input_unregister_device(ts->input);
361 static const struct i2c_device_id tsc2007_idtable[] = {
366 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
368 static struct i2c_driver tsc2007_driver = {
370 .owner = THIS_MODULE,
373 .id_table = tsc2007_idtable,
374 .probe = tsc2007_probe,
375 .remove = __devexit_p(tsc2007_remove),
378 static int __init tsc2007_init(void)
380 return i2c_add_driver(&tsc2007_driver);
383 static void __exit tsc2007_exit(void)
385 i2c_del_driver(&tsc2007_driver);
388 module_init(tsc2007_init);
389 module_exit(tsc2007_exit);
391 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
392 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
393 MODULE_LICENSE("GPL");