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 touchscreen_report_pos(input, &ts->prop, tc.x, tc.y, false);
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_stop(struct tsc2007 * ts)174 static void tsc2007_stop(struct tsc2007 *ts)
175 {
176 ts->stopped = true;
177 mb();
178 wake_up(&ts->wait);
179
180 disable_irq(ts->irq);
181 }
182
tsc2007_open(struct input_dev * input_dev)183 static int tsc2007_open(struct input_dev *input_dev)
184 {
185 struct tsc2007 *ts = input_get_drvdata(input_dev);
186 int err;
187
188 ts->stopped = false;
189 mb();
190
191 enable_irq(ts->irq);
192
193 /* Prepare for touch readings - power down ADC and enable PENIRQ */
194 err = tsc2007_xfer(ts, PWRDOWN);
195 if (err < 0) {
196 tsc2007_stop(ts);
197 return err;
198 }
199
200 return 0;
201 }
202
tsc2007_close(struct input_dev * input_dev)203 static void tsc2007_close(struct input_dev *input_dev)
204 {
205 struct tsc2007 *ts = input_get_drvdata(input_dev);
206
207 tsc2007_stop(ts);
208 }
209
tsc2007_get_pendown_state_gpio(struct device * dev)210 static int tsc2007_get_pendown_state_gpio(struct device *dev)
211 {
212 struct i2c_client *client = to_i2c_client(dev);
213 struct tsc2007 *ts = i2c_get_clientdata(client);
214
215 return gpiod_get_value_cansleep(ts->gpiod);
216 }
217
tsc2007_probe_properties(struct device * dev,struct tsc2007 * ts)218 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts)
219 {
220 u32 val32;
221 u64 val64;
222
223 if (!device_property_read_u32(dev, "ti,max-rt", &val32))
224 ts->max_rt = val32;
225 else
226 ts->max_rt = MAX_12BIT;
227
228 if (!device_property_read_u32(dev, "ti,fuzzx", &val32))
229 ts->fuzzx = val32;
230
231 if (!device_property_read_u32(dev, "ti,fuzzy", &val32))
232 ts->fuzzy = val32;
233
234 if (!device_property_read_u32(dev, "ti,fuzzz", &val32))
235 ts->fuzzz = val32;
236
237 if (!device_property_read_u64(dev, "ti,poll-period", &val64))
238 ts->poll_period = msecs_to_jiffies(val64);
239 else
240 ts->poll_period = msecs_to_jiffies(1);
241
242 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) {
243 ts->x_plate_ohms = val32;
244 } else {
245 dev_err(dev, "Missing ti,x-plate-ohms device property\n");
246 return -EINVAL;
247 }
248
249 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
250 if (IS_ERR(ts->gpiod))
251 return PTR_ERR(ts->gpiod);
252
253 if (ts->gpiod)
254 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
255 else
256 dev_warn(dev, "Pen down GPIO is not specified in properties\n");
257
258 return 0;
259 }
260
tsc2007_probe_pdev(struct device * dev,struct tsc2007 * ts,const struct tsc2007_platform_data * pdata,const struct i2c_device_id * id)261 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts,
262 const struct tsc2007_platform_data *pdata,
263 const struct i2c_device_id *id)
264 {
265 ts->model = pdata->model;
266 ts->x_plate_ohms = pdata->x_plate_ohms;
267 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
268 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
269 ts->get_pendown_state = pdata->get_pendown_state;
270 ts->clear_penirq = pdata->clear_penirq;
271 ts->fuzzx = pdata->fuzzx;
272 ts->fuzzy = pdata->fuzzy;
273 ts->fuzzz = pdata->fuzzz;
274
275 if (pdata->x_plate_ohms == 0) {
276 dev_err(dev, "x_plate_ohms is not set up in platform data\n");
277 return -EINVAL;
278 }
279
280 return 0;
281 }
282
tsc2007_call_exit_platform_hw(void * data)283 static void tsc2007_call_exit_platform_hw(void *data)
284 {
285 struct device *dev = data;
286 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
287
288 pdata->exit_platform_hw();
289 }
290
tsc2007_probe(struct i2c_client * client)291 static int tsc2007_probe(struct i2c_client *client)
292 {
293 const struct i2c_device_id *id = i2c_client_get_device_id(client);
294 const struct tsc2007_platform_data *pdata =
295 dev_get_platdata(&client->dev);
296 struct tsc2007 *ts;
297 struct input_dev *input_dev;
298 int err;
299
300 if (!i2c_check_functionality(client->adapter,
301 I2C_FUNC_SMBUS_READ_WORD_DATA))
302 return -EIO;
303
304 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
305 if (!ts)
306 return -ENOMEM;
307
308 if (pdata)
309 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id);
310 else
311 err = tsc2007_probe_properties(&client->dev, ts);
312 if (err)
313 return err;
314
315 input_dev = devm_input_allocate_device(&client->dev);
316 if (!input_dev)
317 return -ENOMEM;
318
319 i2c_set_clientdata(client, ts);
320
321 ts->client = client;
322 ts->irq = client->irq;
323 ts->input = input_dev;
324
325 init_waitqueue_head(&ts->wait);
326 mutex_init(&ts->mlock);
327
328 snprintf(ts->phys, sizeof(ts->phys),
329 "%s/input0", dev_name(&client->dev));
330
331 input_dev->name = "TSC2007 Touchscreen";
332 input_dev->phys = ts->phys;
333 input_dev->id.bustype = BUS_I2C;
334
335 input_dev->open = tsc2007_open;
336 input_dev->close = tsc2007_close;
337
338 input_set_drvdata(input_dev, ts);
339
340 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
341 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
342 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
343 touchscreen_parse_properties(input_dev, false, &ts->prop);
344 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
345 ts->fuzzz, 0);
346
347 if (pdata) {
348 if (pdata->exit_platform_hw) {
349 err = devm_add_action(&client->dev,
350 tsc2007_call_exit_platform_hw,
351 &client->dev);
352 if (err) {
353 dev_err(&client->dev,
354 "Failed to register exit_platform_hw action, %d\n",
355 err);
356 return err;
357 }
358 }
359
360 if (pdata->init_platform_hw)
361 pdata->init_platform_hw();
362 }
363
364 err = devm_request_threaded_irq(&client->dev, ts->irq,
365 NULL, tsc2007_soft_irq,
366 IRQF_ONESHOT,
367 client->dev.driver->name, ts);
368 if (err) {
369 dev_err(&client->dev, "Failed to request irq %d: %d\n",
370 ts->irq, err);
371 return err;
372 }
373
374 tsc2007_stop(ts);
375
376 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
377 err = tsc2007_xfer(ts, PWRDOWN);
378 if (err < 0) {
379 dev_err(&client->dev,
380 "Failed to setup chip: %d\n", err);
381 return err; /* chip does not respond */
382 }
383
384 err = input_register_device(input_dev);
385 if (err) {
386 dev_err(&client->dev,
387 "Failed to register input device: %d\n", err);
388 return err;
389 }
390
391 err = tsc2007_iio_configure(ts);
392 if (err) {
393 dev_err(&client->dev,
394 "Failed to register with IIO: %d\n", err);
395 return err;
396 }
397
398 return 0;
399 }
400
401 static const struct i2c_device_id tsc2007_idtable[] = {
402 { "tsc2007" },
403 { }
404 };
405
406 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
407
408 static const struct of_device_id tsc2007_of_match[] = {
409 { .compatible = "ti,tsc2007" },
410 { /* sentinel */ }
411 };
412 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
413
414 static struct i2c_driver tsc2007_driver = {
415 .driver = {
416 .name = "tsc2007",
417 .of_match_table = tsc2007_of_match,
418 },
419 .id_table = tsc2007_idtable,
420 .probe = tsc2007_probe,
421 };
422
423 module_i2c_driver(tsc2007_driver);
424
425 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
426 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
427 MODULE_LICENSE("GPL");
428