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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 TSC2007_MEASURE_TEMP0 (0x0 << 4)
31#define TSC2007_MEASURE_AUX (0x2 << 4)
32#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
33#define TSC2007_ACTIVATE_XN (0x8 << 4)
34#define TSC2007_ACTIVATE_YN (0x9 << 4)
35#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
36#define TSC2007_SETUP (0xb << 4)
37#define TSC2007_MEASURE_X (0xc << 4)
38#define TSC2007_MEASURE_Y (0xd << 4)
39#define TSC2007_MEASURE_Z1 (0xe << 4)
40#define TSC2007_MEASURE_Z2 (0xf << 4)
41
42#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
43#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
44#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
45#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
46
47#define TSC2007_12BIT (0x0 << 1)
48#define TSC2007_8BIT (0x1 << 1)
49
50#define MAX_12BIT ((1 << 12) - 1)
51
52#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
53
54#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
55#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
56#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
57#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
58#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
59
60struct ts_event {
61 u16 x;
62 u16 y;
63 u16 z1, z2;
64};
65
66struct tsc2007 {
67 struct input_dev *input;
68 char phys[32];
69 struct delayed_work work;
70
71 struct i2c_client *client;
72
73 u16 model;
74 u16 x_plate_ohms;
75 u16 max_rt;
76 unsigned long poll_delay;
77 unsigned long poll_period;
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 bool debounced = false;
160 struct ts_event tc;
161 u32 rt;
162
163 /*
164 * NOTE: We can't rely on the pressure to determine the pen down
165 * state, even though this controller has a pressure sensor.
166 * The pressure value can fluctuate for quite a while after
167 * lifting the pen and in some cases may not even settle at the
168 * expected value.
169 *
170 * The only safe way to check for the pen up condition is in the
171 * work function by reading the pen signal state (it's a GPIO
172 * and IRQ). Unfortunately such callback is not always available,
173 * in that case we have rely on the pressure anyway.
174 */
175 if (ts->get_pendown_state) {
176 if (unlikely(!ts->get_pendown_state())) {
177 tsc2007_send_up_event(ts);
178 ts->pendown = false;
179 goto out;
180 }
181
182 dev_dbg(&ts->client->dev, "pen is still down\n");
183 }
184
185 tsc2007_read_values(ts, &tc);
186
187 rt = tsc2007_calculate_pressure(ts, &tc);
188 if (rt > ts->max_rt) {
189 /*
190 * Sample found inconsistent by debouncing or pressure is
191 * beyond the maximum. Don't report it to user space,
192 * repeat at least once more the measurement.
193 */
194 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
195 debounced = true;
196 goto out;
197
198 }
199
200 if (rt) {
201 struct input_dev *input = ts->input;
202
203 if (!ts->pendown) {
204 dev_dbg(&ts->client->dev, "DOWN\n");
205
206 input_report_key(input, BTN_TOUCH, 1);
207 ts->pendown = true;
208 }
209
210 input_report_abs(input, ABS_X, tc.x);
211 input_report_abs(input, ABS_Y, tc.y);
212 input_report_abs(input, ABS_PRESSURE, rt);
213
214 input_sync(input);
215
216 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
217 tc.x, tc.y, rt);
218
219 } else if (!ts->get_pendown_state && ts->pendown) {
220 /*
221 * We don't have callback to check pendown state, so we
222 * have to assume that since pressure reported is 0 the
223 * pen was lifted up.
224 */
225 tsc2007_send_up_event(ts);
226 ts->pendown = false;
227 }
228
229 out:
230 if (ts->pendown || debounced)
231 schedule_delayed_work(&ts->work,
232 msecs_to_jiffies(ts->poll_period));
233 else
234 enable_irq(ts->irq);
235}
236
237static irqreturn_t tsc2007_irq(int irq, void *handle)
238{
239 struct tsc2007 *ts = handle;
240
241 if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
242 disable_irq_nosync(ts->irq);
243 schedule_delayed_work(&ts->work,
244 msecs_to_jiffies(ts->poll_delay));
245 }
246
247 if (ts->clear_penirq)
248 ts->clear_penirq();
249
250 return IRQ_HANDLED;
251}
252
253static void tsc2007_free_irq(struct tsc2007 *ts)
254{
255 free_irq(ts->irq, ts);
256 if (cancel_delayed_work_sync(&ts->work)) {
257 /*
258 * Work was pending, therefore we need to enable
259 * IRQ here to balance the disable_irq() done in the
260 * interrupt handler.
261 */
262 enable_irq(ts->irq);
263 }
264}
265
266static int __devinit tsc2007_probe(struct i2c_client *client,
267 const struct i2c_device_id *id)
268{
269 struct tsc2007 *ts;
270 struct tsc2007_platform_data *pdata = client->dev.platform_data;
271 struct input_dev *input_dev;
272 int err;
273
274 if (!pdata) {
275 dev_err(&client->dev, "platform data is required!\n");
276 return -EINVAL;
277 }
278
279 if (!i2c_check_functionality(client->adapter,
280 I2C_FUNC_SMBUS_READ_WORD_DATA))
281 return -EIO;
282
283 ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
284 input_dev = input_allocate_device();
285 if (!ts || !input_dev) {
286 err = -ENOMEM;
287 goto err_free_mem;
288 }
289
290 ts->client = client;
291 ts->irq = client->irq;
292 ts->input = input_dev;
293 INIT_DELAYED_WORK(&ts->work, tsc2007_work);
294
295 ts->model = pdata->model;
296 ts->x_plate_ohms = pdata->x_plate_ohms;
297 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
298 ts->poll_delay = pdata->poll_delay ? : 1;
299 ts->poll_period = pdata->poll_period ? : 1;
300 ts->get_pendown_state = pdata->get_pendown_state;
301 ts->clear_penirq = pdata->clear_penirq;
302
303 snprintf(ts->phys, sizeof(ts->phys),
304 "%s/input0", dev_name(&client->dev));
305
306 input_dev->name = "TSC2007 Touchscreen";
307 input_dev->phys = ts->phys;
308 input_dev->id.bustype = BUS_I2C;
309
310 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
311 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
312
313 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, pdata->fuzzx, 0);
314 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, pdata->fuzzy, 0);
315 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
316 pdata->fuzzz, 0);
317
318 if (pdata->init_platform_hw)
319 pdata->init_platform_hw();
320
321 err = request_irq(ts->irq, tsc2007_irq, 0,
322 client->dev.driver->name, ts);
323 if (err < 0) {
324 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
325 goto err_free_mem;
326 }
327
328 /* Prepare for touch readings - power down ADC and enable PENIRQ */
329 err = tsc2007_xfer(ts, PWRDOWN);
330 if (err < 0)
331 goto err_free_irq;
332
333 err = input_register_device(input_dev);
334 if (err)
335 goto err_free_irq;
336
337 i2c_set_clientdata(client, ts);
338
339 return 0;
340
341 err_free_irq:
342 tsc2007_free_irq(ts);
343 if (pdata->exit_platform_hw)
344 pdata->exit_platform_hw();
345 err_free_mem:
346 input_free_device(input_dev);
347 kfree(ts);
348 return err;
349}
350
351static int __devexit tsc2007_remove(struct i2c_client *client)
352{
353 struct tsc2007 *ts = i2c_get_clientdata(client);
354 struct tsc2007_platform_data *pdata = client->dev.platform_data;
355
356 tsc2007_free_irq(ts);
357
358 if (pdata->exit_platform_hw)
359 pdata->exit_platform_hw();
360
361 input_unregister_device(ts->input);
362 kfree(ts);
363
364 return 0;
365}
366
367static const struct i2c_device_id tsc2007_idtable[] = {
368 { "tsc2007", 0 },
369 { }
370};
371
372MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
373
374static struct i2c_driver tsc2007_driver = {
375 .driver = {
376 .owner = THIS_MODULE,
377 .name = "tsc2007"
378 },
379 .id_table = tsc2007_idtable,
380 .probe = tsc2007_probe,
381 .remove = __devexit_p(tsc2007_remove),
382};
383
384static int __init tsc2007_init(void)
385{
386 return i2c_add_driver(&tsc2007_driver);
387}
388
389static void __exit tsc2007_exit(void)
390{
391 i2c_del_driver(&tsc2007_driver);
392}
393
394module_init(tsc2007_init);
395module_exit(tsc2007_exit);
396
397MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
398MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
399MODULE_LICENSE("GPL");