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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#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
63struct ts_event {
64 u16 x;
65 u16 y;
66 u16 z1, z2;
67};
68
69struct 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;
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
93static 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
115static 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
131static 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
151static 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
173static 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,
218 msecs_to_jiffies(ts->poll_period));
219 }
220
221 dev_dbg(&ts->client->dev, "UP\n");
222
223 input_report_key(input, BTN_TOUCH, 0);
224 input_report_abs(input, ABS_PRESSURE, 0);
225 input_sync(input);
226
227 if (ts->clear_penirq)
228 ts->clear_penirq();
229
230 return IRQ_HANDLED;
231}
232
233static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
234{
235 struct tsc2007 *ts = handle;
236
237 if (tsc2007_is_pen_down(ts))
238 return IRQ_WAKE_THREAD;
239
240 if (ts->clear_penirq)
241 ts->clear_penirq();
242
243 return IRQ_HANDLED;
244}
245
246static void tsc2007_stop(struct tsc2007 *ts)
247{
248 ts->stopped = true;
249 mb();
250 wake_up(&ts->wait);
251
252 disable_irq(ts->irq);
253}
254
255static int tsc2007_open(struct input_dev *input_dev)
256{
257 struct tsc2007 *ts = input_get_drvdata(input_dev);
258 int err;
259
260 ts->stopped = false;
261 mb();
262
263 enable_irq(ts->irq);
264
265 /* Prepare for touch readings - power down ADC and enable PENIRQ */
266 err = tsc2007_xfer(ts, PWRDOWN);
267 if (err < 0) {
268 tsc2007_stop(ts);
269 return err;
270 }
271
272 return 0;
273}
274
275static void tsc2007_close(struct input_dev *input_dev)
276{
277 struct tsc2007 *ts = input_get_drvdata(input_dev);
278
279 tsc2007_stop(ts);
280}
281
282#ifdef CONFIG_OF
283static int tsc2007_get_pendown_state_gpio(struct device *dev)
284{
285 struct i2c_client *client = to_i2c_client(dev);
286 struct tsc2007 *ts = i2c_get_clientdata(client);
287
288 return !gpio_get_value(ts->gpio);
289}
290
291static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
292{
293 struct device_node *np = client->dev.of_node;
294 u32 val32;
295 u64 val64;
296
297 if (!np) {
298 dev_err(&client->dev, "missing device tree data\n");
299 return -EINVAL;
300 }
301
302 if (!of_property_read_u32(np, "ti,max-rt", &val32))
303 ts->max_rt = val32;
304 else
305 ts->max_rt = MAX_12BIT;
306
307 if (!of_property_read_u32(np, "ti,fuzzx", &val32))
308 ts->fuzzx = val32;
309
310 if (!of_property_read_u32(np, "ti,fuzzy", &val32))
311 ts->fuzzy = val32;
312
313 if (!of_property_read_u32(np, "ti,fuzzz", &val32))
314 ts->fuzzz = val32;
315
316 if (!of_property_read_u64(np, "ti,poll-period", &val64))
317 ts->poll_period = val64;
318 else
319 ts->poll_period = 1;
320
321 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
322 ts->x_plate_ohms = val32;
323 } else {
324 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
325 return -EINVAL;
326 }
327
328 ts->gpio = of_get_gpio(np, 0);
329 if (gpio_is_valid(ts->gpio))
330 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
331 else
332 dev_warn(&client->dev,
333 "GPIO not specified in DT (of_get_gpio returned %d)\n",
334 ts->gpio);
335
336 return 0;
337}
338#else
339static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
340{
341 dev_err(&client->dev, "platform data is required!\n");
342 return -EINVAL;
343}
344#endif
345
346static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
347 const struct tsc2007_platform_data *pdata,
348 const struct i2c_device_id *id)
349{
350 ts->model = pdata->model;
351 ts->x_plate_ohms = pdata->x_plate_ohms;
352 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
353 ts->poll_period = pdata->poll_period ? : 1;
354 ts->get_pendown_state = pdata->get_pendown_state;
355 ts->clear_penirq = pdata->clear_penirq;
356 ts->fuzzx = pdata->fuzzx;
357 ts->fuzzy = pdata->fuzzy;
358 ts->fuzzz = pdata->fuzzz;
359
360 if (pdata->x_plate_ohms == 0) {
361 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
362 return -EINVAL;
363 }
364
365 return 0;
366}
367
368static void tsc2007_call_exit_platform_hw(void *data)
369{
370 struct device *dev = data;
371 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
372
373 pdata->exit_platform_hw();
374}
375
376static int tsc2007_probe(struct i2c_client *client,
377 const struct i2c_device_id *id)
378{
379 const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
380 struct tsc2007 *ts;
381 struct input_dev *input_dev;
382 int err;
383
384 if (!i2c_check_functionality(client->adapter,
385 I2C_FUNC_SMBUS_READ_WORD_DATA))
386 return -EIO;
387
388 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
389 if (!ts)
390 return -ENOMEM;
391
392 if (pdata)
393 err = tsc2007_probe_pdev(client, ts, pdata, id);
394 else
395 err = tsc2007_probe_dt(client, ts);
396 if (err)
397 return err;
398
399 input_dev = devm_input_allocate_device(&client->dev);
400 if (!input_dev)
401 return -ENOMEM;
402
403 i2c_set_clientdata(client, ts);
404
405 ts->client = client;
406 ts->irq = client->irq;
407 ts->input = input_dev;
408 init_waitqueue_head(&ts->wait);
409
410 snprintf(ts->phys, sizeof(ts->phys),
411 "%s/input0", dev_name(&client->dev));
412
413 input_dev->name = "TSC2007 Touchscreen";
414 input_dev->phys = ts->phys;
415 input_dev->id.bustype = BUS_I2C;
416
417 input_dev->open = tsc2007_open;
418 input_dev->close = tsc2007_close;
419
420 input_set_drvdata(input_dev, ts);
421
422 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
423 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
424
425 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
426 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
427 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
428 ts->fuzzz, 0);
429
430 if (pdata) {
431 if (pdata->exit_platform_hw) {
432 err = devm_add_action(&client->dev,
433 tsc2007_call_exit_platform_hw,
434 &client->dev);
435 if (err) {
436 dev_err(&client->dev,
437 "Failed to register exit_platform_hw action, %d\n",
438 err);
439 return err;
440 }
441 }
442
443 if (pdata->init_platform_hw)
444 pdata->init_platform_hw();
445 }
446
447 err = devm_request_threaded_irq(&client->dev, ts->irq,
448 tsc2007_hard_irq, tsc2007_soft_irq,
449 IRQF_ONESHOT,
450 client->dev.driver->name, ts);
451 if (err) {
452 dev_err(&client->dev, "Failed to request irq %d: %d\n",
453 ts->irq, err);
454 return err;
455 }
456
457 tsc2007_stop(ts);
458
459 err = input_register_device(input_dev);
460 if (err) {
461 dev_err(&client->dev,
462 "Failed to register input device: %d\n", err);
463 return err;
464 }
465
466 return 0;
467}
468
469static const struct i2c_device_id tsc2007_idtable[] = {
470 { "tsc2007", 0 },
471 { }
472};
473
474MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
475
476#ifdef CONFIG_OF
477static const struct of_device_id tsc2007_of_match[] = {
478 { .compatible = "ti,tsc2007" },
479 { /* sentinel */ }
480};
481MODULE_DEVICE_TABLE(of, tsc2007_of_match);
482#endif
483
484static struct i2c_driver tsc2007_driver = {
485 .driver = {
486 .owner = THIS_MODULE,
487 .name = "tsc2007",
488 .of_match_table = of_match_ptr(tsc2007_of_match),
489 },
490 .id_table = tsc2007_idtable,
491 .probe = tsc2007_probe,
492};
493
494module_i2c_driver(tsc2007_driver);
495
496MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
497MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
498MODULE_LICENSE("GPL");