1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * drivers/input/touchscreen/tsc2007.c
4 *
5 * Copyright (c) 2008 MtekVision Co., Ltd.
6 * Kwangwoo Lee <kwlee@mtekvision.com>
7 *
8 * Using code from:
9 * - ads7846.c
10 * Copyright (c) 2005 David Brownell
11 * Copyright (c) 2006 Nokia Corporation
12 * - corgi_ts.c
13 * Copyright (C) 2004-2005 Richard Purdie
14 * - omap_ts.[hc], ads7846.h, ts_osk.c
15 * Copyright (C) 2002 MontaVista Software
16 * Copyright (C) 2004 Texas Instruments
17 * Copyright (C) 2005 Dirk Behme
18 */
19
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/input.h>
23 #include <linux/interrupt.h>
24 #include <linux/i2c.h>
25 #include <linux/of_device.h>
26 #include <linux/of_gpio.h>
27 #include <linux/platform_data/tsc2007.h>
28 #include "tsc2007.h"
29
tsc2007_xfer(struct tsc2007 * tsc,u8 cmd)30 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
31 {
32 s32 data;
33 u16 val;
34
35 data = i2c_smbus_read_word_data(tsc->client, cmd);
36 if (data < 0) {
37 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
38 return data;
39 }
40
41 /* The protocol and raw data format from i2c interface:
42 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
43 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
44 */
45 val = swab16(data) >> 4;
46
47 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
48
49 return val;
50 }
51
tsc2007_read_values(struct tsc2007 * tsc,struct ts_event * tc)52 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
53 {
54 /* y- still on; turn on only y+ (and ADC) */
55 tc->y = tsc2007_xfer(tsc, READ_Y);
56
57 /* turn y- off, x+ on, then leave in lowpower */
58 tc->x = tsc2007_xfer(tsc, READ_X);
59
60 /* turn y+ off, x- on; we'll use formula #1 */
61 tc->z1 = tsc2007_xfer(tsc, READ_Z1);
62 tc->z2 = tsc2007_xfer(tsc, READ_Z2);
63
64 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
65 tsc2007_xfer(tsc, PWRDOWN);
66 }
67
tsc2007_calculate_resistance(struct tsc2007 * tsc,struct ts_event * tc)68 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc)
69 {
70 u32 rt = 0;
71
72 /* range filtering */
73 if (tc->x == MAX_12BIT)
74 tc->x = 0;
75
76 if (likely(tc->x && tc->z1)) {
77 /* compute touch resistance using equation #1 */
78 rt = tc->z2 - tc->z1;
79 rt *= tc->x;
80 rt *= tsc->x_plate_ohms;
81 rt /= tc->z1;
82 rt = (rt + 2047) >> 12;
83 }
84
85 return rt;
86 }
87
tsc2007_is_pen_down(struct tsc2007 * ts)88 bool tsc2007_is_pen_down(struct tsc2007 *ts)
89 {
90 /*
91 * NOTE: We can't rely on the pressure to determine the pen down
92 * state, even though this controller has a pressure sensor.
93 * The pressure value can fluctuate for quite a while after
94 * lifting the pen and in some cases may not even settle at the
95 * expected value.
96 *
97 * The only safe way to check for the pen up condition is in the
98 * work function by reading the pen signal state (it's a GPIO
99 * and IRQ). Unfortunately such callback is not always available,
100 * in that case we assume that the pen is down and expect caller
101 * to fall back on the pressure reading.
102 */
103
104 if (!ts->get_pendown_state)
105 return true;
106
107 return ts->get_pendown_state(&ts->client->dev);
108 }
109
tsc2007_soft_irq(int irq,void * handle)110 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
111 {
112 struct tsc2007 *ts = handle;
113 struct input_dev *input = ts->input;
114 struct ts_event tc;
115 u32 rt;
116
117 while (!ts->stopped && tsc2007_is_pen_down(ts)) {
118
119 /* pen is down, continue with the measurement */
120
121 mutex_lock(&ts->mlock);
122 tsc2007_read_values(ts, &tc);
123 mutex_unlock(&ts->mlock);
124
125 rt = tsc2007_calculate_resistance(ts, &tc);
126
127 if (!rt && !ts->get_pendown_state) {
128 /*
129 * If pressure reported is 0 and we don't have
130 * callback to check pendown state, we have to
131 * assume that pen was lifted up.
132 */
133 break;
134 }
135
136 if (rt <= ts->max_rt) {
137 dev_dbg(&ts->client->dev,
138 "DOWN point(%4d,%4d), resistance (%4u)\n",
139 tc.x, tc.y, rt);
140
141 rt = ts->max_rt - rt;
142
143 input_report_key(input, BTN_TOUCH, 1);
144 input_report_abs(input, ABS_X, tc.x);
145 input_report_abs(input, ABS_Y, tc.y);
146 input_report_abs(input, ABS_PRESSURE, rt);
147
148 input_sync(input);
149
150 } else {
151 /*
152 * Sample found inconsistent by debouncing or pressure is
153 * beyond the maximum. Don't report it to user space,
154 * repeat at least once more the measurement.
155 */
156 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
157 }
158
159 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
160 }
161
162 dev_dbg(&ts->client->dev, "UP\n");
163
164 input_report_key(input, BTN_TOUCH, 0);
165 input_report_abs(input, ABS_PRESSURE, 0);
166 input_sync(input);
167
168 if (ts->clear_penirq)
169 ts->clear_penirq();
170
171 return IRQ_HANDLED;
172 }
173
tsc2007_hard_irq(int irq,void * handle)174 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
175 {
176 struct tsc2007 *ts = handle;
177
178 if (tsc2007_is_pen_down(ts))
179 return IRQ_WAKE_THREAD;
180
181 if (ts->clear_penirq)
182 ts->clear_penirq();
183
184 return IRQ_HANDLED;
185 }
186
tsc2007_stop(struct tsc2007 * ts)187 static void tsc2007_stop(struct tsc2007 *ts)
188 {
189 ts->stopped = true;
190 mb();
191 wake_up(&ts->wait);
192
193 disable_irq(ts->irq);
194 }
195
tsc2007_open(struct input_dev * input_dev)196 static int tsc2007_open(struct input_dev *input_dev)
197 {
198 struct tsc2007 *ts = input_get_drvdata(input_dev);
199 int err;
200
201 ts->stopped = false;
202 mb();
203
204 enable_irq(ts->irq);
205
206 /* Prepare for touch readings - power down ADC and enable PENIRQ */
207 err = tsc2007_xfer(ts, PWRDOWN);
208 if (err < 0) {
209 tsc2007_stop(ts);
210 return err;
211 }
212
213 return 0;
214 }
215
tsc2007_close(struct input_dev * input_dev)216 static void tsc2007_close(struct input_dev *input_dev)
217 {
218 struct tsc2007 *ts = input_get_drvdata(input_dev);
219
220 tsc2007_stop(ts);
221 }
222
223 #ifdef CONFIG_OF
tsc2007_get_pendown_state_gpio(struct device * dev)224 static int tsc2007_get_pendown_state_gpio(struct device *dev)
225 {
226 struct i2c_client *client = to_i2c_client(dev);
227 struct tsc2007 *ts = i2c_get_clientdata(client);
228
229 return !gpio_get_value(ts->gpio);
230 }
231
tsc2007_probe_dt(struct i2c_client * client,struct tsc2007 * ts)232 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
233 {
234 struct device_node *np = client->dev.of_node;
235 u32 val32;
236 u64 val64;
237
238 if (!np) {
239 dev_err(&client->dev, "missing device tree data\n");
240 return -EINVAL;
241 }
242
243 if (!of_property_read_u32(np, "ti,max-rt", &val32))
244 ts->max_rt = val32;
245 else
246 ts->max_rt = MAX_12BIT;
247
248 if (!of_property_read_u32(np, "ti,fuzzx", &val32))
249 ts->fuzzx = val32;
250
251 if (!of_property_read_u32(np, "ti,fuzzy", &val32))
252 ts->fuzzy = val32;
253
254 if (!of_property_read_u32(np, "ti,fuzzz", &val32))
255 ts->fuzzz = val32;
256
257 if (!of_property_read_u64(np, "ti,poll-period", &val64))
258 ts->poll_period = msecs_to_jiffies(val64);
259 else
260 ts->poll_period = msecs_to_jiffies(1);
261
262 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
263 ts->x_plate_ohms = val32;
264 } else {
265 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
266 return -EINVAL;
267 }
268
269 ts->gpio = of_get_gpio(np, 0);
270 if (gpio_is_valid(ts->gpio))
271 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
272 else
273 dev_warn(&client->dev,
274 "GPIO not specified in DT (of_get_gpio returned %d)\n",
275 ts->gpio);
276
277 return 0;
278 }
279 #else
tsc2007_probe_dt(struct i2c_client * client,struct tsc2007 * ts)280 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
281 {
282 dev_err(&client->dev, "platform data is required!\n");
283 return -EINVAL;
284 }
285 #endif
286
tsc2007_probe_pdev(struct i2c_client * client,struct tsc2007 * ts,const struct tsc2007_platform_data * pdata,const struct i2c_device_id * id)287 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
288 const struct tsc2007_platform_data *pdata,
289 const struct i2c_device_id *id)
290 {
291 ts->model = pdata->model;
292 ts->x_plate_ohms = pdata->x_plate_ohms;
293 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
294 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
295 ts->get_pendown_state = pdata->get_pendown_state;
296 ts->clear_penirq = pdata->clear_penirq;
297 ts->fuzzx = pdata->fuzzx;
298 ts->fuzzy = pdata->fuzzy;
299 ts->fuzzz = pdata->fuzzz;
300
301 if (pdata->x_plate_ohms == 0) {
302 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
303 return -EINVAL;
304 }
305
306 return 0;
307 }
308
tsc2007_call_exit_platform_hw(void * data)309 static void tsc2007_call_exit_platform_hw(void *data)
310 {
311 struct device *dev = data;
312 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
313
314 pdata->exit_platform_hw();
315 }
316
tsc2007_probe(struct i2c_client * client,const struct i2c_device_id * id)317 static int tsc2007_probe(struct i2c_client *client,
318 const struct i2c_device_id *id)
319 {
320 const struct tsc2007_platform_data *pdata =
321 dev_get_platdata(&client->dev);
322 struct tsc2007 *ts;
323 struct input_dev *input_dev;
324 int err;
325
326 if (!i2c_check_functionality(client->adapter,
327 I2C_FUNC_SMBUS_READ_WORD_DATA))
328 return -EIO;
329
330 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
331 if (!ts)
332 return -ENOMEM;
333
334 if (pdata)
335 err = tsc2007_probe_pdev(client, ts, pdata, id);
336 else
337 err = tsc2007_probe_dt(client, ts);
338 if (err)
339 return err;
340
341 input_dev = devm_input_allocate_device(&client->dev);
342 if (!input_dev)
343 return -ENOMEM;
344
345 i2c_set_clientdata(client, ts);
346
347 ts->client = client;
348 ts->irq = client->irq;
349 ts->input = input_dev;
350
351 init_waitqueue_head(&ts->wait);
352 mutex_init(&ts->mlock);
353
354 snprintf(ts->phys, sizeof(ts->phys),
355 "%s/input0", dev_name(&client->dev));
356
357 input_dev->name = "TSC2007 Touchscreen";
358 input_dev->phys = ts->phys;
359 input_dev->id.bustype = BUS_I2C;
360
361 input_dev->open = tsc2007_open;
362 input_dev->close = tsc2007_close;
363
364 input_set_drvdata(input_dev, ts);
365
366 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
367
368 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
369 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
370 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
371 ts->fuzzz, 0);
372
373 if (pdata) {
374 if (pdata->exit_platform_hw) {
375 err = devm_add_action(&client->dev,
376 tsc2007_call_exit_platform_hw,
377 &client->dev);
378 if (err) {
379 dev_err(&client->dev,
380 "Failed to register exit_platform_hw action, %d\n",
381 err);
382 return err;
383 }
384 }
385
386 if (pdata->init_platform_hw)
387 pdata->init_platform_hw();
388 }
389
390 err = devm_request_threaded_irq(&client->dev, ts->irq,
391 tsc2007_hard_irq, tsc2007_soft_irq,
392 IRQF_ONESHOT,
393 client->dev.driver->name, ts);
394 if (err) {
395 dev_err(&client->dev, "Failed to request irq %d: %d\n",
396 ts->irq, err);
397 return err;
398 }
399
400 tsc2007_stop(ts);
401
402 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
403 err = tsc2007_xfer(ts, PWRDOWN);
404 if (err < 0) {
405 dev_err(&client->dev,
406 "Failed to setup chip: %d\n", err);
407 return err; /* chip does not respond */
408 }
409
410 err = input_register_device(input_dev);
411 if (err) {
412 dev_err(&client->dev,
413 "Failed to register input device: %d\n", err);
414 return err;
415 }
416
417 err = tsc2007_iio_configure(ts);
418 if (err) {
419 dev_err(&client->dev,
420 "Failed to register with IIO: %d\n", err);
421 return err;
422 }
423
424 return 0;
425 }
426
427 static const struct i2c_device_id tsc2007_idtable[] = {
428 { "tsc2007", 0 },
429 { }
430 };
431
432 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
433
434 #ifdef CONFIG_OF
435 static const struct of_device_id tsc2007_of_match[] = {
436 { .compatible = "ti,tsc2007" },
437 { /* sentinel */ }
438 };
439 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
440 #endif
441
442 static struct i2c_driver tsc2007_driver = {
443 .driver = {
444 .name = "tsc2007",
445 .of_match_table = of_match_ptr(tsc2007_of_match),
446 },
447 .id_table = tsc2007_idtable,
448 .probe = tsc2007_probe,
449 };
450
451 module_i2c_driver(tsc2007_driver);
452
453 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
454 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
455 MODULE_LICENSE("GPL");
456