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
60 struct ts_event {
61 u16 x;
62 u16 y;
63 u16 z1, z2;
64 };
65
66 struct tsc2007 {
67 struct input_dev *input;
68 char phys[32];
69
70 struct i2c_client *client;
71
72 u16 model;
73 u16 x_plate_ohms;
74 u16 max_rt;
75 unsigned long poll_delay;
76 unsigned long poll_period;
77
78 int irq;
79
80 wait_queue_head_t wait;
81 bool stopped;
82
83 int (*get_pendown_state)(void);
84 void (*clear_penirq)(void);
85 };
86
tsc2007_xfer(struct tsc2007 * tsc,u8 cmd)87 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
88 {
89 s32 data;
90 u16 val;
91
92 data = i2c_smbus_read_word_data(tsc->client, cmd);
93 if (data < 0) {
94 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
95 return data;
96 }
97
98 /* The protocol and raw data format from i2c interface:
99 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
100 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
101 */
102 val = swab16(data) >> 4;
103
104 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
105
106 return val;
107 }
108
tsc2007_read_values(struct tsc2007 * tsc,struct ts_event * tc)109 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
110 {
111 /* y- still on; turn on only y+ (and ADC) */
112 tc->y = tsc2007_xfer(tsc, READ_Y);
113
114 /* turn y- off, x+ on, then leave in lowpower */
115 tc->x = tsc2007_xfer(tsc, READ_X);
116
117 /* turn y+ off, x- on; we'll use formula #1 */
118 tc->z1 = tsc2007_xfer(tsc, READ_Z1);
119 tc->z2 = tsc2007_xfer(tsc, READ_Z2);
120
121 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
122 tsc2007_xfer(tsc, PWRDOWN);
123 }
124
tsc2007_calculate_pressure(struct tsc2007 * tsc,struct ts_event * tc)125 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
126 {
127 u32 rt = 0;
128
129 /* range filtering */
130 if (tc->x == MAX_12BIT)
131 tc->x = 0;
132
133 if (likely(tc->x && tc->z1)) {
134 /* compute touch pressure resistance using equation #1 */
135 rt = tc->z2 - tc->z1;
136 rt *= tc->x;
137 rt *= tsc->x_plate_ohms;
138 rt /= tc->z1;
139 rt = (rt + 2047) >> 12;
140 }
141
142 return rt;
143 }
144
tsc2007_is_pen_down(struct tsc2007 * ts)145 static bool tsc2007_is_pen_down(struct tsc2007 *ts)
146 {
147 /*
148 * NOTE: We can't rely on the pressure to determine the pen down
149 * state, even though this controller has a pressure sensor.
150 * The pressure value can fluctuate for quite a while after
151 * lifting the pen and in some cases may not even settle at the
152 * expected value.
153 *
154 * The only safe way to check for the pen up condition is in the
155 * work function by reading the pen signal state (it's a GPIO
156 * and IRQ). Unfortunately such callback is not always available,
157 * in that case we assume that the pen is down and expect caller
158 * to fall back on the pressure reading.
159 */
160
161 if (!ts->get_pendown_state)
162 return true;
163
164 return ts->get_pendown_state();
165 }
166
tsc2007_soft_irq(int irq,void * handle)167 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
168 {
169 struct tsc2007 *ts = handle;
170 struct input_dev *input = ts->input;
171 struct ts_event tc;
172 u32 rt;
173
174 while (!ts->stopped && tsc2007_is_pen_down(ts)) {
175
176 /* pen is down, continue with the measurement */
177 tsc2007_read_values(ts, &tc);
178
179 rt = tsc2007_calculate_pressure(ts, &tc);
180
181 if (rt == 0 && !ts->get_pendown_state) {
182 /*
183 * If pressure reported is 0 and we don't have
184 * callback to check pendown state, we have to
185 * assume that pen was lifted up.
186 */
187 break;
188 }
189
190 if (rt <= ts->max_rt) {
191 dev_dbg(&ts->client->dev,
192 "DOWN point(%4d,%4d), pressure (%4u)\n",
193 tc.x, tc.y, rt);
194
195 input_report_key(input, BTN_TOUCH, 1);
196 input_report_abs(input, ABS_X, tc.x);
197 input_report_abs(input, ABS_Y, tc.y);
198 input_report_abs(input, ABS_PRESSURE, rt);
199
200 input_sync(input);
201
202 } else {
203 /*
204 * Sample found inconsistent by debouncing or pressure is
205 * beyond the maximum. Don't report it to user space,
206 * repeat at least once more the measurement.
207 */
208 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
209 }
210
211 wait_event_timeout(ts->wait, ts->stopped,
212 msecs_to_jiffies(ts->poll_period));
213 }
214
215 dev_dbg(&ts->client->dev, "UP\n");
216
217 input_report_key(input, BTN_TOUCH, 0);
218 input_report_abs(input, ABS_PRESSURE, 0);
219 input_sync(input);
220
221 if (ts->clear_penirq)
222 ts->clear_penirq();
223
224 return IRQ_HANDLED;
225 }
226
tsc2007_hard_irq(int irq,void * handle)227 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
228 {
229 struct tsc2007 *ts = handle;
230
231 if (!ts->get_pendown_state || likely(ts->get_pendown_state()))
232 return IRQ_WAKE_THREAD;
233
234 if (ts->clear_penirq)
235 ts->clear_penirq();
236
237 return IRQ_HANDLED;
238 }
239
tsc2007_stop(struct tsc2007 * ts)240 static void tsc2007_stop(struct tsc2007 *ts)
241 {
242 ts->stopped = true;
243 mb();
244 wake_up(&ts->wait);
245
246 disable_irq(ts->irq);
247 }
248
tsc2007_open(struct input_dev * input_dev)249 static int tsc2007_open(struct input_dev *input_dev)
250 {
251 struct tsc2007 *ts = input_get_drvdata(input_dev);
252 int err;
253
254 ts->stopped = false;
255 mb();
256
257 enable_irq(ts->irq);
258
259 /* Prepare for touch readings - power down ADC and enable PENIRQ */
260 err = tsc2007_xfer(ts, PWRDOWN);
261 if (err < 0) {
262 tsc2007_stop(ts);
263 return err;
264 }
265
266 return 0;
267 }
268
tsc2007_close(struct input_dev * input_dev)269 static void tsc2007_close(struct input_dev *input_dev)
270 {
271 struct tsc2007 *ts = input_get_drvdata(input_dev);
272
273 tsc2007_stop(ts);
274 }
275
tsc2007_probe(struct i2c_client * client,const struct i2c_device_id * id)276 static int __devinit tsc2007_probe(struct i2c_client *client,
277 const struct i2c_device_id *id)
278 {
279 struct tsc2007 *ts;
280 struct tsc2007_platform_data *pdata = client->dev.platform_data;
281 struct input_dev *input_dev;
282 int err;
283
284 if (!pdata) {
285 dev_err(&client->dev, "platform data is required!\n");
286 return -EINVAL;
287 }
288
289 if (!i2c_check_functionality(client->adapter,
290 I2C_FUNC_SMBUS_READ_WORD_DATA))
291 return -EIO;
292
293 ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
294 input_dev = input_allocate_device();
295 if (!ts || !input_dev) {
296 err = -ENOMEM;
297 goto err_free_mem;
298 }
299
300 ts->client = client;
301 ts->irq = client->irq;
302 ts->input = input_dev;
303 init_waitqueue_head(&ts->wait);
304
305 ts->model = pdata->model;
306 ts->x_plate_ohms = pdata->x_plate_ohms;
307 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
308 ts->poll_delay = pdata->poll_delay ? : 1;
309 ts->poll_period = pdata->poll_period ? : 1;
310 ts->get_pendown_state = pdata->get_pendown_state;
311 ts->clear_penirq = pdata->clear_penirq;
312
313 if (pdata->x_plate_ohms == 0) {
314 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
315 err = -EINVAL;
316 goto err_free_mem;
317 }
318
319 snprintf(ts->phys, sizeof(ts->phys),
320 "%s/input0", dev_name(&client->dev));
321
322 input_dev->name = "TSC2007 Touchscreen";
323 input_dev->phys = ts->phys;
324 input_dev->id.bustype = BUS_I2C;
325
326 input_dev->open = tsc2007_open;
327 input_dev->close = tsc2007_close;
328
329 input_set_drvdata(input_dev, ts);
330
331 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
332 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
333
334 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, pdata->fuzzx, 0);
335 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, pdata->fuzzy, 0);
336 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
337 pdata->fuzzz, 0);
338
339 if (pdata->init_platform_hw)
340 pdata->init_platform_hw();
341
342 err = request_threaded_irq(ts->irq, tsc2007_hard_irq, tsc2007_soft_irq,
343 IRQF_ONESHOT, client->dev.driver->name, ts);
344 if (err < 0) {
345 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
346 goto err_free_mem;
347 }
348
349 tsc2007_stop(ts);
350
351 err = input_register_device(input_dev);
352 if (err)
353 goto err_free_irq;
354
355 i2c_set_clientdata(client, ts);
356
357 return 0;
358
359 err_free_irq:
360 free_irq(ts->irq, ts);
361 if (pdata->exit_platform_hw)
362 pdata->exit_platform_hw();
363 err_free_mem:
364 input_free_device(input_dev);
365 kfree(ts);
366 return err;
367 }
368
tsc2007_remove(struct i2c_client * client)369 static int __devexit tsc2007_remove(struct i2c_client *client)
370 {
371 struct tsc2007 *ts = i2c_get_clientdata(client);
372 struct tsc2007_platform_data *pdata = client->dev.platform_data;
373
374 free_irq(ts->irq, ts);
375
376 if (pdata->exit_platform_hw)
377 pdata->exit_platform_hw();
378
379 input_unregister_device(ts->input);
380 kfree(ts);
381
382 return 0;
383 }
384
385 static const struct i2c_device_id tsc2007_idtable[] = {
386 { "tsc2007", 0 },
387 { }
388 };
389
390 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
391
392 static struct i2c_driver tsc2007_driver = {
393 .driver = {
394 .owner = THIS_MODULE,
395 .name = "tsc2007"
396 },
397 .id_table = tsc2007_idtable,
398 .probe = tsc2007_probe,
399 .remove = __devexit_p(tsc2007_remove),
400 };
401
402 module_i2c_driver(tsc2007_driver);
403
404 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
405 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
406 MODULE_LICENSE("GPL");
407