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 
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 
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 
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 
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 
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 
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 
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 
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 
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
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 
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
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 
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 
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 
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