blob: b75dc2990574e9549d483846d30f77e6f0eb08c1 [file] [log] [blame]
Kwangwoo Lee50b6f1f2008-12-20 04:26:01 -05001/*
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/hrtimer.h>
25#include <linux/slab.h>
26#include <linux/input.h>
27#include <linux/interrupt.h>
28#include <linux/i2c.h>
29#include <linux/i2c/tsc2007.h>
30
31#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
32#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
33
34#define TSC2007_MEASURE_TEMP0 (0x0 << 4)
35#define TSC2007_MEASURE_AUX (0x2 << 4)
36#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
37#define TSC2007_ACTIVATE_XN (0x8 << 4)
38#define TSC2007_ACTIVATE_YN (0x9 << 4)
39#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
40#define TSC2007_SETUP (0xb << 4)
41#define TSC2007_MEASURE_X (0xc << 4)
42#define TSC2007_MEASURE_Y (0xd << 4)
43#define TSC2007_MEASURE_Z1 (0xe << 4)
44#define TSC2007_MEASURE_Z2 (0xf << 4)
45
46#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
47#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
48#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
49#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
50
51#define TSC2007_12BIT (0x0 << 1)
52#define TSC2007_8BIT (0x1 << 1)
53
54#define MAX_12BIT ((1 << 12) - 1)
55
56#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
57
58#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
59#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
60#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
61#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
62#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
63
64struct ts_event {
65 u16 x;
66 u16 y;
67 u16 z1, z2;
68};
69
70struct tsc2007 {
71 struct input_dev *input;
72 char phys[32];
73 struct hrtimer timer;
74 struct ts_event tc;
75
76 struct i2c_client *client;
77
78 spinlock_t lock;
79
80 u16 model;
81 u16 x_plate_ohms;
82
83 unsigned pendown;
84 int irq;
85
86 int (*get_pendown_state)(void);
87 void (*clear_penirq)(void);
88};
89
90static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
91{
92 s32 data;
93 u16 val;
94
95 data = i2c_smbus_read_word_data(tsc->client, cmd);
96 if (data < 0) {
97 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
98 return data;
99 }
100
101 /* The protocol and raw data format from i2c interface:
102 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
103 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
104 */
105 val = swab16(data) >> 4;
106
107 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
108
109 return val;
110}
111
112static void tsc2007_send_event(void *tsc)
113{
114 struct tsc2007 *ts = tsc;
115 u32 rt;
116 u16 x, y, z1, z2;
117
118 x = ts->tc.x;
119 y = ts->tc.y;
120 z1 = ts->tc.z1;
121 z2 = ts->tc.z2;
122
123 /* range filtering */
124 if (x == MAX_12BIT)
125 x = 0;
126
127 if (likely(x && z1)) {
128 /* compute touch pressure resistance using equation #1 */
129 rt = z2;
130 rt -= z1;
131 rt *= x;
132 rt *= ts->x_plate_ohms;
133 rt /= z1;
134 rt = (rt + 2047) >> 12;
135 } else
136 rt = 0;
137
138 /* Sample found inconsistent by debouncing or pressure is beyond
139 * the maximum. Don't report it to user space, repeat at least
140 * once more the measurement
141 */
142 if (rt > MAX_12BIT) {
143 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
144
145 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
146 HRTIMER_MODE_REL);
147 return;
148 }
149
150 /* NOTE: We can't rely on the pressure to determine the pen down
151 * state, even this controller has a pressure sensor. The pressure
152 * value can fluctuate for quite a while after lifting the pen and
153 * in some cases may not even settle at the expected value.
154 *
155 * The only safe way to check for the pen up condition is in the
156 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
157 */
158 if (rt) {
159 struct input_dev *input = ts->input;
160
161 if (!ts->pendown) {
162 dev_dbg(&ts->client->dev, "DOWN\n");
163
164 input_report_key(input, BTN_TOUCH, 1);
165 ts->pendown = 1;
166 }
167
168 input_report_abs(input, ABS_X, x);
169 input_report_abs(input, ABS_Y, y);
170 input_report_abs(input, ABS_PRESSURE, rt);
171
172 input_sync(input);
173
174 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
175 x, y, rt);
176 }
177
178 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
179 HRTIMER_MODE_REL);
180}
181
182static int tsc2007_read_values(struct tsc2007 *tsc)
183{
184 /* y- still on; turn on only y+ (and ADC) */
185 tsc->tc.y = tsc2007_xfer(tsc, READ_Y);
186
187 /* turn y- off, x+ on, then leave in lowpower */
188 tsc->tc.x = tsc2007_xfer(tsc, READ_X);
189
190 /* turn y+ off, x- on; we'll use formula #1 */
191 tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
192 tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);
193
194 /* power down */
195 tsc2007_xfer(tsc, PWRDOWN);
196
197 return 0;
198}
199
200static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
201{
202 struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
203
204 spin_lock_irq(&ts->lock);
205
206 if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
207 struct input_dev *input = ts->input;
208
209 dev_dbg(&ts->client->dev, "UP\n");
210
211 input_report_key(input, BTN_TOUCH, 0);
212 input_report_abs(input, ABS_PRESSURE, 0);
213 input_sync(input);
214
215 ts->pendown = 0;
216 enable_irq(ts->irq);
217 } else {
218 /* pen is still down, continue with the measurement */
219 dev_dbg(&ts->client->dev, "pen is still down\n");
220
221 tsc2007_read_values(ts);
222 tsc2007_send_event(ts);
223 }
224
225 spin_unlock_irq(&ts->lock);
226
227 return HRTIMER_NORESTART;
228}
229
230static irqreturn_t tsc2007_irq(int irq, void *handle)
231{
232 struct tsc2007 *ts = handle;
233 unsigned long flags;
234
235 spin_lock_irqsave(&ts->lock, flags);
236
237 if (likely(ts->get_pendown_state())) {
238 disable_irq(ts->irq);
239 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
240 HRTIMER_MODE_REL);
241 }
242
243 if (ts->clear_penirq)
244 ts->clear_penirq();
245
246 spin_unlock_irqrestore(&ts->lock, flags);
247
248 return IRQ_HANDLED;
249}
250
251static int tsc2007_probe(struct i2c_client *client,
252 const struct i2c_device_id *id)
253{
254 struct tsc2007 *ts;
255 struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
256 struct input_dev *input_dev;
257 int err;
258
259 if (!pdata) {
260 dev_err(&client->dev, "platform data is required!\n");
261 return -EINVAL;
262 }
263
264 if (!i2c_check_functionality(client->adapter,
265 I2C_FUNC_SMBUS_READ_WORD_DATA))
266 return -EIO;
267
268 ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
269 input_dev = input_allocate_device();
270 if (!ts || !input_dev) {
271 err = -ENOMEM;
272 goto err_free_mem;
273 }
274
275 ts->client = client;
276 i2c_set_clientdata(client, ts);
277
278 ts->input = input_dev;
279
280 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
281 ts->timer.function = tsc2007_timer;
282
283 spin_lock_init(&ts->lock);
284
285 ts->model = pdata->model;
286 ts->x_plate_ohms = pdata->x_plate_ohms;
287 ts->get_pendown_state = pdata->get_pendown_state;
288 ts->clear_penirq = pdata->clear_penirq;
289
290 pdata->init_platform_hw();
291
292 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", client->dev.bus_id);
293
294 input_dev->name = "TSC2007 Touchscreen";
295 input_dev->phys = ts->phys;
296 input_dev->id.bustype = BUS_I2C;
297
298 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
299 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
300
301 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
302 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
303 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
304
305 tsc2007_read_values(ts);
306
307 ts->irq = client->irq;
308
309 err = request_irq(ts->irq, tsc2007_irq, 0,
310 client->dev.driver->name, ts);
311 if (err < 0) {
312 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
313 goto err_free_mem;
314 }
315
316 err = input_register_device(input_dev);
317 if (err)
318 goto err_free_irq;
319
320 dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
321
322 return 0;
323
324 err_free_irq:
325 free_irq(ts->irq, ts);
326 hrtimer_cancel(&ts->timer);
327 err_free_mem:
328 input_free_device(input_dev);
329 kfree(ts);
330 return err;
331}
332
333static int tsc2007_remove(struct i2c_client *client)
334{
335 struct tsc2007 *ts = i2c_get_clientdata(client);
336 struct tsc2007_platform_data *pdata;
337
338 pdata = client->dev.platform_data;
339 pdata->exit_platform_hw();
340
341 free_irq(ts->irq, ts);
342 hrtimer_cancel(&ts->timer);
343 input_unregister_device(ts->input);
344 kfree(ts);
345
346 return 0;
347}
348
349static struct i2c_device_id tsc2007_idtable[] = {
350 { "tsc2007", 0 },
351 { }
352};
353
354MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
355
356static struct i2c_driver tsc2007_driver = {
357 .driver = {
358 .owner = THIS_MODULE,
359 .name = "tsc2007"
360 },
361 .id_table = tsc2007_idtable,
362 .probe = tsc2007_probe,
363 .remove = tsc2007_remove,
364};
365
366static int __init tsc2007_init(void)
367{
368 return i2c_add_driver(&tsc2007_driver);
369}
370
371static void __exit tsc2007_exit(void)
372{
373 i2c_del_driver(&tsc2007_driver);
374}
375
376module_init(tsc2007_init);
377module_exit(tsc2007_exit);
378
379MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
380MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
381MODULE_LICENSE("GPL");