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/gpio/consumer.h>
23 #include <linux/input.h>
24 #include <linux/interrupt.h>
25 #include <linux/i2c.h>
26 #include <linux/mod_devicetable.h>
27 #include <linux/property.h>
28 #include <linux/platform_data/tsc2007.h>
29 #include "tsc2007.h"
30
tsc2007_xfer(struct tsc2007 * tsc,u8 cmd)31 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
32 {
33 s32 data;
34 u16 val;
35
36 data = i2c_smbus_read_word_data(tsc->client, cmd);
37 if (data < 0) {
38 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
39 return data;
40 }
41
42 /* The protocol and raw data format from i2c interface:
43 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
44 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
45 */
46 val = swab16(data) >> 4;
47
48 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
49
50 return val;
51 }
52
tsc2007_read_values(struct tsc2007 * tsc,struct ts_event * tc)53 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
54 {
55 /* y- still on; turn on only y+ (and ADC) */
56 tc->y = tsc2007_xfer(tsc, READ_Y);
57
58 /* turn y- off, x+ on, then leave in lowpower */
59 tc->x = tsc2007_xfer(tsc, READ_X);
60
61 /* turn y+ off, x- on; we'll use formula #1 */
62 tc->z1 = tsc2007_xfer(tsc, READ_Z1);
63 tc->z2 = tsc2007_xfer(tsc, READ_Z2);
64
65 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
66 tsc2007_xfer(tsc, PWRDOWN);
67 }
68
tsc2007_calculate_resistance(struct tsc2007 * tsc,struct ts_event * tc)69 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc)
70 {
71 u32 rt = 0;
72
73 /* range filtering */
74 if (tc->x == MAX_12BIT)
75 tc->x = 0;
76
77 if (likely(tc->x && tc->z1)) {
78 /* compute touch resistance using equation #1 */
79 rt = tc->z2 - tc->z1;
80 rt *= tc->x;
81 rt *= tsc->x_plate_ohms;
82 rt /= tc->z1;
83 rt = (rt + 2047) >> 12;
84 }
85
86 return rt;
87 }
88
tsc2007_is_pen_down(struct tsc2007 * ts)89 bool tsc2007_is_pen_down(struct tsc2007 *ts)
90 {
91 /*
92 * NOTE: We can't rely on the pressure to determine the pen down
93 * state, even though this controller has a pressure sensor.
94 * The pressure value can fluctuate for quite a while after
95 * lifting the pen and in some cases may not even settle at the
96 * expected value.
97 *
98 * The only safe way to check for the pen up condition is in the
99 * work function by reading the pen signal state (it's a GPIO
100 * and IRQ). Unfortunately such callback is not always available,
101 * in that case we assume that the pen is down and expect caller
102 * to fall back on the pressure reading.
103 */
104
105 if (!ts->get_pendown_state)
106 return true;
107
108 return ts->get_pendown_state(&ts->client->dev);
109 }
110
tsc2007_soft_irq(int irq,void * handle)111 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
112 {
113 struct tsc2007 *ts = handle;
114 struct input_dev *input = ts->input;
115 struct ts_event tc;
116 u32 rt;
117
118 while (!ts->stopped && tsc2007_is_pen_down(ts)) {
119
120 /* pen is down, continue with the measurement */
121
122 mutex_lock(&ts->mlock);
123 tsc2007_read_values(ts, &tc);
124 mutex_unlock(&ts->mlock);
125
126 rt = tsc2007_calculate_resistance(ts, &tc);
127
128 if (!rt && !ts->get_pendown_state) {
129 /*
130 * If pressure reported is 0 and we don't have
131 * callback to check pendown state, we have to
132 * assume that pen was lifted up.
133 */
134 break;
135 }
136
137 if (rt <= ts->max_rt) {
138 dev_dbg(&ts->client->dev,
139 "DOWN point(%4d,%4d), resistance (%4u)\n",
140 tc.x, tc.y, rt);
141
142 rt = ts->max_rt - rt;
143
144 input_report_key(input, BTN_TOUCH, 1);
145 input_report_abs(input, ABS_X, tc.x);
146 input_report_abs(input, ABS_Y, tc.y);
147 input_report_abs(input, ABS_PRESSURE, rt);
148
149 input_sync(input);
150
151 } else {
152 /*
153 * Sample found inconsistent by debouncing or pressure is
154 * beyond the maximum. Don't report it to user space,
155 * repeat at least once more the measurement.
156 */
157 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
158 }
159
160 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
161 }
162
163 dev_dbg(&ts->client->dev, "UP\n");
164
165 input_report_key(input, BTN_TOUCH, 0);
166 input_report_abs(input, ABS_PRESSURE, 0);
167 input_sync(input);
168
169 if (ts->clear_penirq)
170 ts->clear_penirq();
171
172 return IRQ_HANDLED;
173 }
174
tsc2007_stop(struct tsc2007 * ts)175 static void tsc2007_stop(struct tsc2007 *ts)
176 {
177 ts->stopped = true;
178 mb();
179 wake_up(&ts->wait);
180
181 disable_irq(ts->irq);
182 }
183
tsc2007_open(struct input_dev * input_dev)184 static int tsc2007_open(struct input_dev *input_dev)
185 {
186 struct tsc2007 *ts = input_get_drvdata(input_dev);
187 int err;
188
189 ts->stopped = false;
190 mb();
191
192 enable_irq(ts->irq);
193
194 /* Prepare for touch readings - power down ADC and enable PENIRQ */
195 err = tsc2007_xfer(ts, PWRDOWN);
196 if (err < 0) {
197 tsc2007_stop(ts);
198 return err;
199 }
200
201 return 0;
202 }
203
tsc2007_close(struct input_dev * input_dev)204 static void tsc2007_close(struct input_dev *input_dev)
205 {
206 struct tsc2007 *ts = input_get_drvdata(input_dev);
207
208 tsc2007_stop(ts);
209 }
210
tsc2007_get_pendown_state_gpio(struct device * dev)211 static int tsc2007_get_pendown_state_gpio(struct device *dev)
212 {
213 struct i2c_client *client = to_i2c_client(dev);
214 struct tsc2007 *ts = i2c_get_clientdata(client);
215
216 return gpiod_get_value_cansleep(ts->gpiod);
217 }
218
tsc2007_probe_properties(struct device * dev,struct tsc2007 * ts)219 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts)
220 {
221 u32 val32;
222 u64 val64;
223
224 if (!device_property_read_u32(dev, "ti,max-rt", &val32))
225 ts->max_rt = val32;
226 else
227 ts->max_rt = MAX_12BIT;
228
229 if (!device_property_read_u32(dev, "ti,fuzzx", &val32))
230 ts->fuzzx = val32;
231
232 if (!device_property_read_u32(dev, "ti,fuzzy", &val32))
233 ts->fuzzy = val32;
234
235 if (!device_property_read_u32(dev, "ti,fuzzz", &val32))
236 ts->fuzzz = val32;
237
238 if (!device_property_read_u64(dev, "ti,poll-period", &val64))
239 ts->poll_period = msecs_to_jiffies(val64);
240 else
241 ts->poll_period = msecs_to_jiffies(1);
242
243 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) {
244 ts->x_plate_ohms = val32;
245 } else {
246 dev_err(dev, "Missing ti,x-plate-ohms device property\n");
247 return -EINVAL;
248 }
249
250 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
251 if (IS_ERR(ts->gpiod))
252 return PTR_ERR(ts->gpiod);
253
254 if (ts->gpiod)
255 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
256 else
257 dev_warn(dev, "Pen down GPIO is not specified in properties\n");
258
259 return 0;
260 }
261
tsc2007_probe_pdev(struct device * dev,struct tsc2007 * ts,const struct tsc2007_platform_data * pdata,const struct i2c_device_id * id)262 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts,
263 const struct tsc2007_platform_data *pdata,
264 const struct i2c_device_id *id)
265 {
266 ts->model = pdata->model;
267 ts->x_plate_ohms = pdata->x_plate_ohms;
268 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
269 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
270 ts->get_pendown_state = pdata->get_pendown_state;
271 ts->clear_penirq = pdata->clear_penirq;
272 ts->fuzzx = pdata->fuzzx;
273 ts->fuzzy = pdata->fuzzy;
274 ts->fuzzz = pdata->fuzzz;
275
276 if (pdata->x_plate_ohms == 0) {
277 dev_err(dev, "x_plate_ohms is not set up in platform data\n");
278 return -EINVAL;
279 }
280
281 return 0;
282 }
283
tsc2007_call_exit_platform_hw(void * data)284 static void tsc2007_call_exit_platform_hw(void *data)
285 {
286 struct device *dev = data;
287 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
288
289 pdata->exit_platform_hw();
290 }
291
tsc2007_probe(struct i2c_client * client)292 static int tsc2007_probe(struct i2c_client *client)
293 {
294 const struct i2c_device_id *id = i2c_client_get_device_id(client);
295 const struct tsc2007_platform_data *pdata =
296 dev_get_platdata(&client->dev);
297 struct tsc2007 *ts;
298 struct input_dev *input_dev;
299 int err;
300
301 if (!i2c_check_functionality(client->adapter,
302 I2C_FUNC_SMBUS_READ_WORD_DATA))
303 return -EIO;
304
305 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
306 if (!ts)
307 return -ENOMEM;
308
309 if (pdata)
310 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id);
311 else
312 err = tsc2007_probe_properties(&client->dev, ts);
313 if (err)
314 return err;
315
316 input_dev = devm_input_allocate_device(&client->dev);
317 if (!input_dev)
318 return -ENOMEM;
319
320 i2c_set_clientdata(client, ts);
321
322 ts->client = client;
323 ts->irq = client->irq;
324 ts->input = input_dev;
325
326 init_waitqueue_head(&ts->wait);
327 mutex_init(&ts->mlock);
328
329 snprintf(ts->phys, sizeof(ts->phys),
330 "%s/input0", dev_name(&client->dev));
331
332 input_dev->name = "TSC2007 Touchscreen";
333 input_dev->phys = ts->phys;
334 input_dev->id.bustype = BUS_I2C;
335
336 input_dev->open = tsc2007_open;
337 input_dev->close = tsc2007_close;
338
339 input_set_drvdata(input_dev, ts);
340
341 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
342
343 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
344 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
345 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
346 ts->fuzzz, 0);
347
348 if (pdata) {
349 if (pdata->exit_platform_hw) {
350 err = devm_add_action(&client->dev,
351 tsc2007_call_exit_platform_hw,
352 &client->dev);
353 if (err) {
354 dev_err(&client->dev,
355 "Failed to register exit_platform_hw action, %d\n",
356 err);
357 return err;
358 }
359 }
360
361 if (pdata->init_platform_hw)
362 pdata->init_platform_hw();
363 }
364
365 err = devm_request_threaded_irq(&client->dev, ts->irq,
366 NULL, tsc2007_soft_irq,
367 IRQF_ONESHOT,
368 client->dev.driver->name, ts);
369 if (err) {
370 dev_err(&client->dev, "Failed to request irq %d: %d\n",
371 ts->irq, err);
372 return err;
373 }
374
375 tsc2007_stop(ts);
376
377 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
378 err = tsc2007_xfer(ts, PWRDOWN);
379 if (err < 0) {
380 dev_err(&client->dev,
381 "Failed to setup chip: %d\n", err);
382 return err; /* chip does not respond */
383 }
384
385 err = input_register_device(input_dev);
386 if (err) {
387 dev_err(&client->dev,
388 "Failed to register input device: %d\n", err);
389 return err;
390 }
391
392 err = tsc2007_iio_configure(ts);
393 if (err) {
394 dev_err(&client->dev,
395 "Failed to register with IIO: %d\n", err);
396 return err;
397 }
398
399 return 0;
400 }
401
402 static const struct i2c_device_id tsc2007_idtable[] = {
403 { "tsc2007", 0 },
404 { }
405 };
406
407 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
408
409 static const struct of_device_id tsc2007_of_match[] = {
410 { .compatible = "ti,tsc2007" },
411 { /* sentinel */ }
412 };
413 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
414
415 static struct i2c_driver tsc2007_driver = {
416 .driver = {
417 .name = "tsc2007",
418 .of_match_table = tsc2007_of_match,
419 },
420 .id_table = tsc2007_idtable,
421 .probe = tsc2007_probe,
422 };
423
424 module_i2c_driver(tsc2007_driver);
425
426 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
427 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
428 MODULE_LICENSE("GPL");
429