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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
31int 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
53static 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
69u32 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
89bool 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
111static 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
175static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
176{
177 struct tsc2007 *ts = handle;
178
179 if (tsc2007_is_pen_down(ts))
180 return IRQ_WAKE_THREAD;
181
182 if (ts->clear_penirq)
183 ts->clear_penirq();
184
185 return IRQ_HANDLED;
186}
187
188static void tsc2007_stop(struct tsc2007 *ts)
189{
190 ts->stopped = true;
191 mb();
192 wake_up(&ts->wait);
193
194 disable_irq(ts->irq);
195}
196
197static int tsc2007_open(struct input_dev *input_dev)
198{
199 struct tsc2007 *ts = input_get_drvdata(input_dev);
200 int err;
201
202 ts->stopped = false;
203 mb();
204
205 enable_irq(ts->irq);
206
207 /* Prepare for touch readings - power down ADC and enable PENIRQ */
208 err = tsc2007_xfer(ts, PWRDOWN);
209 if (err < 0) {
210 tsc2007_stop(ts);
211 return err;
212 }
213
214 return 0;
215}
216
217static void tsc2007_close(struct input_dev *input_dev)
218{
219 struct tsc2007 *ts = input_get_drvdata(input_dev);
220
221 tsc2007_stop(ts);
222}
223
224static 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 gpiod_get_value(ts->gpiod);
230}
231
232static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts)
233{
234 u32 val32;
235 u64 val64;
236
237 if (!device_property_read_u32(dev, "ti,max-rt", &val32))
238 ts->max_rt = val32;
239 else
240 ts->max_rt = MAX_12BIT;
241
242 if (!device_property_read_u32(dev, "ti,fuzzx", &val32))
243 ts->fuzzx = val32;
244
245 if (!device_property_read_u32(dev, "ti,fuzzy", &val32))
246 ts->fuzzy = val32;
247
248 if (!device_property_read_u32(dev, "ti,fuzzz", &val32))
249 ts->fuzzz = val32;
250
251 if (!device_property_read_u64(dev, "ti,poll-period", &val64))
252 ts->poll_period = msecs_to_jiffies(val64);
253 else
254 ts->poll_period = msecs_to_jiffies(1);
255
256 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) {
257 ts->x_plate_ohms = val32;
258 } else {
259 dev_err(dev, "Missing ti,x-plate-ohms device property\n");
260 return -EINVAL;
261 }
262
263 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
264 if (IS_ERR(ts->gpiod))
265 return PTR_ERR(ts->gpiod);
266
267 if (ts->gpiod)
268 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
269 else
270 dev_warn(dev, "Pen down GPIO is not specified in properties\n");
271
272 return 0;
273}
274
275static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts,
276 const struct tsc2007_platform_data *pdata,
277 const struct i2c_device_id *id)
278{
279 ts->model = pdata->model;
280 ts->x_plate_ohms = pdata->x_plate_ohms;
281 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
282 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
283 ts->get_pendown_state = pdata->get_pendown_state;
284 ts->clear_penirq = pdata->clear_penirq;
285 ts->fuzzx = pdata->fuzzx;
286 ts->fuzzy = pdata->fuzzy;
287 ts->fuzzz = pdata->fuzzz;
288
289 if (pdata->x_plate_ohms == 0) {
290 dev_err(dev, "x_plate_ohms is not set up in platform data\n");
291 return -EINVAL;
292 }
293
294 return 0;
295}
296
297static void tsc2007_call_exit_platform_hw(void *data)
298{
299 struct device *dev = data;
300 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
301
302 pdata->exit_platform_hw();
303}
304
305static int tsc2007_probe(struct i2c_client *client)
306{
307 const struct i2c_device_id *id = i2c_client_get_device_id(client);
308 const struct tsc2007_platform_data *pdata =
309 dev_get_platdata(&client->dev);
310 struct tsc2007 *ts;
311 struct input_dev *input_dev;
312 int err;
313
314 if (!i2c_check_functionality(client->adapter,
315 I2C_FUNC_SMBUS_READ_WORD_DATA))
316 return -EIO;
317
318 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
319 if (!ts)
320 return -ENOMEM;
321
322 if (pdata)
323 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id);
324 else
325 err = tsc2007_probe_properties(&client->dev, ts);
326 if (err)
327 return err;
328
329 input_dev = devm_input_allocate_device(&client->dev);
330 if (!input_dev)
331 return -ENOMEM;
332
333 i2c_set_clientdata(client, ts);
334
335 ts->client = client;
336 ts->irq = client->irq;
337 ts->input = input_dev;
338
339 init_waitqueue_head(&ts->wait);
340 mutex_init(&ts->mlock);
341
342 snprintf(ts->phys, sizeof(ts->phys),
343 "%s/input0", dev_name(&client->dev));
344
345 input_dev->name = "TSC2007 Touchscreen";
346 input_dev->phys = ts->phys;
347 input_dev->id.bustype = BUS_I2C;
348
349 input_dev->open = tsc2007_open;
350 input_dev->close = tsc2007_close;
351
352 input_set_drvdata(input_dev, ts);
353
354 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
355
356 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
357 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
358 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
359 ts->fuzzz, 0);
360
361 if (pdata) {
362 if (pdata->exit_platform_hw) {
363 err = devm_add_action(&client->dev,
364 tsc2007_call_exit_platform_hw,
365 &client->dev);
366 if (err) {
367 dev_err(&client->dev,
368 "Failed to register exit_platform_hw action, %d\n",
369 err);
370 return err;
371 }
372 }
373
374 if (pdata->init_platform_hw)
375 pdata->init_platform_hw();
376 }
377
378 err = devm_request_threaded_irq(&client->dev, ts->irq,
379 tsc2007_hard_irq, tsc2007_soft_irq,
380 IRQF_ONESHOT,
381 client->dev.driver->name, ts);
382 if (err) {
383 dev_err(&client->dev, "Failed to request irq %d: %d\n",
384 ts->irq, err);
385 return err;
386 }
387
388 tsc2007_stop(ts);
389
390 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
391 err = tsc2007_xfer(ts, PWRDOWN);
392 if (err < 0) {
393 dev_err(&client->dev,
394 "Failed to setup chip: %d\n", err);
395 return err; /* chip does not respond */
396 }
397
398 err = input_register_device(input_dev);
399 if (err) {
400 dev_err(&client->dev,
401 "Failed to register input device: %d\n", err);
402 return err;
403 }
404
405 err = tsc2007_iio_configure(ts);
406 if (err) {
407 dev_err(&client->dev,
408 "Failed to register with IIO: %d\n", err);
409 return err;
410 }
411
412 return 0;
413}
414
415static const struct i2c_device_id tsc2007_idtable[] = {
416 { "tsc2007", 0 },
417 { }
418};
419
420MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
421
422static const struct of_device_id tsc2007_of_match[] = {
423 { .compatible = "ti,tsc2007" },
424 { /* sentinel */ }
425};
426MODULE_DEVICE_TABLE(of, tsc2007_of_match);
427
428static struct i2c_driver tsc2007_driver = {
429 .driver = {
430 .name = "tsc2007",
431 .of_match_table = tsc2007_of_match,
432 },
433 .id_table = tsc2007_idtable,
434 .probe_new = tsc2007_probe,
435};
436
437module_i2c_driver(tsc2007_driver);
438
439MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
440MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
441MODULE_LICENSE("GPL");