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 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
184static 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
204static 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
211static 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
219static 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
262static 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
284static 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
292static 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
402static const struct i2c_device_id tsc2007_idtable[] = {
403	{ "tsc2007", 0 },
404	{ }
405};
406
407MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
408
409static const struct of_device_id tsc2007_of_match[] = {
410	{ .compatible = "ti,tsc2007" },
411	{ /* sentinel */ }
412};
413MODULE_DEVICE_TABLE(of, tsc2007_of_match);
414
415static 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
424module_i2c_driver(tsc2007_driver);
425
426MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
427MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
428MODULE_LICENSE("GPL");
429