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 #include <linux/of_device.h>
30 #include <linux/of.h>
31 #include <linux/of_gpio.h>
32
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)
44
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)
49
50 #define TSC2007_12BIT (0x0 << 1)
51 #define TSC2007_8BIT (0x1 << 1)
52
53 #define MAX_12BIT ((1 << 12) - 1)
54
55 #define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
56
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)
62
63 struct ts_event {
64 u16 x;
65 u16 y;
66 u16 z1, z2;
67 };
68
69 struct tsc2007 {
70 struct input_dev *input;
71 char phys[32];
72
73 struct i2c_client *client;
74
75 u16 model;
76 u16 x_plate_ohms;
77 u16 max_rt;
78 unsigned long poll_period; /* in jiffies */
79 int fuzzx;
80 int fuzzy;
81 int fuzzz;
82
83 unsigned gpio;
84 int irq;
85
86 wait_queue_head_t wait;
87 bool stopped;
88
89 int (*get_pendown_state)(struct device *);
90 void (*clear_penirq)(void);
91 };
92
tsc2007_xfer(struct tsc2007 * tsc,u8 cmd)93 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
94 {
95 s32 data;
96 u16 val;
97
98 data = i2c_smbus_read_word_data(tsc->client, cmd);
99 if (data < 0) {
100 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
101 return data;
102 }
103
104 /* The protocol and raw data format from i2c interface:
105 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
106 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
107 */
108 val = swab16(data) >> 4;
109
110 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
111
112 return val;
113 }
114
tsc2007_read_values(struct tsc2007 * tsc,struct ts_event * tc)115 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
116 {
117 /* y- still on; turn on only y+ (and ADC) */
118 tc->y = tsc2007_xfer(tsc, READ_Y);
119
120 /* turn y- off, x+ on, then leave in lowpower */
121 tc->x = tsc2007_xfer(tsc, READ_X);
122
123 /* turn y+ off, x- on; we'll use formula #1 */
124 tc->z1 = tsc2007_xfer(tsc, READ_Z1);
125 tc->z2 = tsc2007_xfer(tsc, READ_Z2);
126
127 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
128 tsc2007_xfer(tsc, PWRDOWN);
129 }
130
tsc2007_calculate_pressure(struct tsc2007 * tsc,struct ts_event * tc)131 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
132 {
133 u32 rt = 0;
134
135 /* range filtering */
136 if (tc->x == MAX_12BIT)
137 tc->x = 0;
138
139 if (likely(tc->x && tc->z1)) {
140 /* compute touch pressure resistance using equation #1 */
141 rt = tc->z2 - tc->z1;
142 rt *= tc->x;
143 rt *= tsc->x_plate_ohms;
144 rt /= tc->z1;
145 rt = (rt + 2047) >> 12;
146 }
147
148 return rt;
149 }
150
tsc2007_is_pen_down(struct tsc2007 * ts)151 static bool tsc2007_is_pen_down(struct tsc2007 *ts)
152 {
153 /*
154 * NOTE: We can't rely on the pressure to determine the pen down
155 * state, even though this controller has a pressure sensor.
156 * The pressure value can fluctuate for quite a while after
157 * lifting the pen and in some cases may not even settle at the
158 * expected value.
159 *
160 * The only safe way to check for the pen up condition is in the
161 * work function by reading the pen signal state (it's a GPIO
162 * and IRQ). Unfortunately such callback is not always available,
163 * in that case we assume that the pen is down and expect caller
164 * to fall back on the pressure reading.
165 */
166
167 if (!ts->get_pendown_state)
168 return true;
169
170 return ts->get_pendown_state(&ts->client->dev);
171 }
172
tsc2007_soft_irq(int irq,void * handle)173 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
174 {
175 struct tsc2007 *ts = handle;
176 struct input_dev *input = ts->input;
177 struct ts_event tc;
178 u32 rt;
179
180 while (!ts->stopped && tsc2007_is_pen_down(ts)) {
181
182 /* pen is down, continue with the measurement */
183 tsc2007_read_values(ts, &tc);
184
185 rt = tsc2007_calculate_pressure(ts, &tc);
186
187 if (!rt && !ts->get_pendown_state) {
188 /*
189 * If pressure reported is 0 and we don't have
190 * callback to check pendown state, we have to
191 * assume that pen was lifted up.
192 */
193 break;
194 }
195
196 if (rt <= ts->max_rt) {
197 dev_dbg(&ts->client->dev,
198 "DOWN point(%4d,%4d), pressure (%4u)\n",
199 tc.x, tc.y, rt);
200
201 input_report_key(input, BTN_TOUCH, 1);
202 input_report_abs(input, ABS_X, tc.x);
203 input_report_abs(input, ABS_Y, tc.y);
204 input_report_abs(input, ABS_PRESSURE, rt);
205
206 input_sync(input);
207
208 } else {
209 /*
210 * Sample found inconsistent by debouncing or pressure is
211 * beyond the maximum. Don't report it to user space,
212 * repeat at least once more the measurement.
213 */
214 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
215 }
216
217 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
218 }
219
220 dev_dbg(&ts->client->dev, "UP\n");
221
222 input_report_key(input, BTN_TOUCH, 0);
223 input_report_abs(input, ABS_PRESSURE, 0);
224 input_sync(input);
225
226 if (ts->clear_penirq)
227 ts->clear_penirq();
228
229 return IRQ_HANDLED;
230 }
231
tsc2007_hard_irq(int irq,void * handle)232 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
233 {
234 struct tsc2007 *ts = handle;
235
236 if (tsc2007_is_pen_down(ts))
237 return IRQ_WAKE_THREAD;
238
239 if (ts->clear_penirq)
240 ts->clear_penirq();
241
242 return IRQ_HANDLED;
243 }
244
tsc2007_stop(struct tsc2007 * ts)245 static void tsc2007_stop(struct tsc2007 *ts)
246 {
247 ts->stopped = true;
248 mb();
249 wake_up(&ts->wait);
250
251 disable_irq(ts->irq);
252 }
253
tsc2007_open(struct input_dev * input_dev)254 static int tsc2007_open(struct input_dev *input_dev)
255 {
256 struct tsc2007 *ts = input_get_drvdata(input_dev);
257 int err;
258
259 ts->stopped = false;
260 mb();
261
262 enable_irq(ts->irq);
263
264 /* Prepare for touch readings - power down ADC and enable PENIRQ */
265 err = tsc2007_xfer(ts, PWRDOWN);
266 if (err < 0) {
267 tsc2007_stop(ts);
268 return err;
269 }
270
271 return 0;
272 }
273
tsc2007_close(struct input_dev * input_dev)274 static void tsc2007_close(struct input_dev *input_dev)
275 {
276 struct tsc2007 *ts = input_get_drvdata(input_dev);
277
278 tsc2007_stop(ts);
279 }
280
281 #ifdef CONFIG_OF
tsc2007_get_pendown_state_gpio(struct device * dev)282 static int tsc2007_get_pendown_state_gpio(struct device *dev)
283 {
284 struct i2c_client *client = to_i2c_client(dev);
285 struct tsc2007 *ts = i2c_get_clientdata(client);
286
287 return !gpio_get_value(ts->gpio);
288 }
289
tsc2007_probe_dt(struct i2c_client * client,struct tsc2007 * ts)290 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
291 {
292 struct device_node *np = client->dev.of_node;
293 u32 val32;
294 u64 val64;
295
296 if (!np) {
297 dev_err(&client->dev, "missing device tree data\n");
298 return -EINVAL;
299 }
300
301 if (!of_property_read_u32(np, "ti,max-rt", &val32))
302 ts->max_rt = val32;
303 else
304 ts->max_rt = MAX_12BIT;
305
306 if (!of_property_read_u32(np, "ti,fuzzx", &val32))
307 ts->fuzzx = val32;
308
309 if (!of_property_read_u32(np, "ti,fuzzy", &val32))
310 ts->fuzzy = val32;
311
312 if (!of_property_read_u32(np, "ti,fuzzz", &val32))
313 ts->fuzzz = val32;
314
315 if (!of_property_read_u64(np, "ti,poll-period", &val64))
316 ts->poll_period = msecs_to_jiffies(val64);
317 else
318 ts->poll_period = msecs_to_jiffies(1);
319
320 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
321 ts->x_plate_ohms = val32;
322 } else {
323 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
324 return -EINVAL;
325 }
326
327 ts->gpio = of_get_gpio(np, 0);
328 if (gpio_is_valid(ts->gpio))
329 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
330 else
331 dev_warn(&client->dev,
332 "GPIO not specified in DT (of_get_gpio returned %d)\n",
333 ts->gpio);
334
335 return 0;
336 }
337 #else
tsc2007_probe_dt(struct i2c_client * client,struct tsc2007 * ts)338 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
339 {
340 dev_err(&client->dev, "platform data is required!\n");
341 return -EINVAL;
342 }
343 #endif
344
tsc2007_probe_pdev(struct i2c_client * client,struct tsc2007 * ts,const struct tsc2007_platform_data * pdata,const struct i2c_device_id * id)345 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
346 const struct tsc2007_platform_data *pdata,
347 const struct i2c_device_id *id)
348 {
349 ts->model = pdata->model;
350 ts->x_plate_ohms = pdata->x_plate_ohms;
351 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
352 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
353 ts->get_pendown_state = pdata->get_pendown_state;
354 ts->clear_penirq = pdata->clear_penirq;
355 ts->fuzzx = pdata->fuzzx;
356 ts->fuzzy = pdata->fuzzy;
357 ts->fuzzz = pdata->fuzzz;
358
359 if (pdata->x_plate_ohms == 0) {
360 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
361 return -EINVAL;
362 }
363
364 return 0;
365 }
366
tsc2007_call_exit_platform_hw(void * data)367 static void tsc2007_call_exit_platform_hw(void *data)
368 {
369 struct device *dev = data;
370 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
371
372 pdata->exit_platform_hw();
373 }
374
tsc2007_probe(struct i2c_client * client,const struct i2c_device_id * id)375 static int tsc2007_probe(struct i2c_client *client,
376 const struct i2c_device_id *id)
377 {
378 const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
379 struct tsc2007 *ts;
380 struct input_dev *input_dev;
381 int err;
382
383 if (!i2c_check_functionality(client->adapter,
384 I2C_FUNC_SMBUS_READ_WORD_DATA))
385 return -EIO;
386
387 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
388 if (!ts)
389 return -ENOMEM;
390
391 if (pdata)
392 err = tsc2007_probe_pdev(client, ts, pdata, id);
393 else
394 err = tsc2007_probe_dt(client, ts);
395 if (err)
396 return err;
397
398 input_dev = devm_input_allocate_device(&client->dev);
399 if (!input_dev)
400 return -ENOMEM;
401
402 i2c_set_clientdata(client, ts);
403
404 ts->client = client;
405 ts->irq = client->irq;
406 ts->input = input_dev;
407 init_waitqueue_head(&ts->wait);
408
409 snprintf(ts->phys, sizeof(ts->phys),
410 "%s/input0", dev_name(&client->dev));
411
412 input_dev->name = "TSC2007 Touchscreen";
413 input_dev->phys = ts->phys;
414 input_dev->id.bustype = BUS_I2C;
415
416 input_dev->open = tsc2007_open;
417 input_dev->close = tsc2007_close;
418
419 input_set_drvdata(input_dev, ts);
420
421 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
422 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
423
424 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
425 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
426 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
427 ts->fuzzz, 0);
428
429 if (pdata) {
430 if (pdata->exit_platform_hw) {
431 err = devm_add_action(&client->dev,
432 tsc2007_call_exit_platform_hw,
433 &client->dev);
434 if (err) {
435 dev_err(&client->dev,
436 "Failed to register exit_platform_hw action, %d\n",
437 err);
438 return err;
439 }
440 }
441
442 if (pdata->init_platform_hw)
443 pdata->init_platform_hw();
444 }
445
446 err = devm_request_threaded_irq(&client->dev, ts->irq,
447 tsc2007_hard_irq, tsc2007_soft_irq,
448 IRQF_ONESHOT,
449 client->dev.driver->name, ts);
450 if (err) {
451 dev_err(&client->dev, "Failed to request irq %d: %d\n",
452 ts->irq, err);
453 return err;
454 }
455
456 tsc2007_stop(ts);
457
458 err = input_register_device(input_dev);
459 if (err) {
460 dev_err(&client->dev,
461 "Failed to register input device: %d\n", err);
462 return err;
463 }
464
465 return 0;
466 }
467
468 static const struct i2c_device_id tsc2007_idtable[] = {
469 { "tsc2007", 0 },
470 { }
471 };
472
473 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
474
475 #ifdef CONFIG_OF
476 static const struct of_device_id tsc2007_of_match[] = {
477 { .compatible = "ti,tsc2007" },
478 { /* sentinel */ }
479 };
480 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
481 #endif
482
483 static struct i2c_driver tsc2007_driver = {
484 .driver = {
485 .name = "tsc2007",
486 .of_match_table = of_match_ptr(tsc2007_of_match),
487 },
488 .id_table = tsc2007_idtable,
489 .probe = tsc2007_probe,
490 };
491
492 module_i2c_driver(tsc2007_driver);
493
494 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
495 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
496 MODULE_LICENSE("GPL");
497