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/drivers/input/touchscreen/eeti_ts.c

http://github.com/mirrors/linux
C | 303 lines | 200 code | 64 blank | 39 comment | 19 complexity | 291a9da47d2ff562dbeff7f5bb5bb38c MD5 | raw file
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Touch Screen driver for EETI's I2C connected touch screen panels
  4 *   Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
  5 *
  6 * See EETI's software guide for the protocol specification:
  7 *   http://home.eeti.com.tw/documentation.html
  8 *
  9 * Based on migor_ts.c
 10 *   Copyright (c) 2008 Magnus Damm
 11 *   Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>
 12 */
 13
 14#include <linux/module.h>
 15#include <linux/kernel.h>
 16#include <linux/input.h>
 17#include <linux/input/touchscreen.h>
 18#include <linux/interrupt.h>
 19#include <linux/i2c.h>
 20#include <linux/timer.h>
 21#include <linux/gpio/consumer.h>
 22#include <linux/of.h>
 23#include <linux/slab.h>
 24#include <asm/unaligned.h>
 25
 26struct eeti_ts {
 27	struct i2c_client *client;
 28	struct input_dev *input;
 29	struct gpio_desc *attn_gpio;
 30	struct touchscreen_properties props;
 31	struct mutex mutex;
 32	bool running;
 33};
 34
 35#define EETI_TS_BITDEPTH	(11)
 36#define EETI_MAXVAL		((1 << (EETI_TS_BITDEPTH + 1)) - 1)
 37
 38#define REPORT_BIT_PRESSED	BIT(0)
 39#define REPORT_BIT_AD0		BIT(1)
 40#define REPORT_BIT_AD1		BIT(2)
 41#define REPORT_BIT_HAS_PRESSURE	BIT(6)
 42#define REPORT_RES_BITS(v)	(((v) >> 1) + EETI_TS_BITDEPTH)
 43
 44static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
 45{
 46	unsigned int res;
 47	u16 x, y;
 48
 49	res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
 50
 51	x = get_unaligned_be16(&buf[1]);
 52	y = get_unaligned_be16(&buf[3]);
 53
 54	/* fix the range to 11 bits */
 55	x >>= res - EETI_TS_BITDEPTH;
 56	y >>= res - EETI_TS_BITDEPTH;
 57
 58	if (buf[0] & REPORT_BIT_HAS_PRESSURE)
 59		input_report_abs(eeti->input, ABS_PRESSURE, buf[5]);
 60
 61	touchscreen_report_pos(eeti->input, &eeti->props, x, y, false);
 62	input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
 63	input_sync(eeti->input);
 64}
 65
 66static int eeti_ts_read(struct eeti_ts *eeti)
 67{
 68	int len, error;
 69	char buf[6];
 70
 71	len = i2c_master_recv(eeti->client, buf, sizeof(buf));
 72	if (len != sizeof(buf)) {
 73		error = len < 0 ? len : -EIO;
 74		dev_err(&eeti->client->dev,
 75			"failed to read touchscreen data: %d\n",
 76			error);
 77		return error;
 78	}
 79
 80	/* Motion packet */
 81	if (buf[0] & 0x80)
 82		eeti_ts_report_event(eeti, buf);
 83
 84	return 0;
 85}
 86
 87static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
 88{
 89	struct eeti_ts *eeti = dev_id;
 90	int error;
 91
 92	mutex_lock(&eeti->mutex);
 93
 94	do {
 95		/*
 96		 * If we have attention GPIO, trust it. Otherwise we'll read
 97		 * once and exit. We assume that in this case we are using
 98		 * level triggered interrupt and it will get raised again
 99		 * if/when there is more data.
100		 */
101		if (eeti->attn_gpio &&
102		    !gpiod_get_value_cansleep(eeti->attn_gpio)) {
103			break;
104		}
105
106		error = eeti_ts_read(eeti);
107		if (error)
108			break;
109
110	} while (eeti->running && eeti->attn_gpio);
111
112	mutex_unlock(&eeti->mutex);
113	return IRQ_HANDLED;
114}
115
116static void eeti_ts_start(struct eeti_ts *eeti)
117{
118	mutex_lock(&eeti->mutex);
119
120	eeti->running = true;
121	enable_irq(eeti->client->irq);
122
123	/*
124	 * Kick the controller in case we are using edge interrupt and
125	 * we missed our edge while interrupt was disabled. We expect
126	 * the attention GPIO to be wired in this case.
127	 */
128	if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio))
129		eeti_ts_read(eeti);
130
131	mutex_unlock(&eeti->mutex);
132}
133
134static void eeti_ts_stop(struct eeti_ts *eeti)
135{
136	/*
137	 * Not locking here, just setting a flag and expect that the
138	 * interrupt thread will notice the flag eventually.
139	 */
140	eeti->running = false;
141	wmb();
142	disable_irq(eeti->client->irq);
143}
144
145static int eeti_ts_open(struct input_dev *dev)
146{
147	struct eeti_ts *eeti = input_get_drvdata(dev);
148
149	eeti_ts_start(eeti);
150
151	return 0;
152}
153
154static void eeti_ts_close(struct input_dev *dev)
155{
156	struct eeti_ts *eeti = input_get_drvdata(dev);
157
158	eeti_ts_stop(eeti);
159}
160
161static int eeti_ts_probe(struct i2c_client *client,
162			 const struct i2c_device_id *idp)
163{
164	struct device *dev = &client->dev;
165	struct eeti_ts *eeti;
166	struct input_dev *input;
167	int error;
168
169	/*
170	 * In contrast to what's described in the datasheet, there seems
171	 * to be no way of probing the presence of that device using I2C
172	 * commands. So we need to blindly believe it is there, and wait
173	 * for interrupts to occur.
174	 */
175
176	eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
177	if (!eeti) {
178		dev_err(dev, "failed to allocate driver data\n");
179		return -ENOMEM;
180	}
181
182	mutex_init(&eeti->mutex);
183
184	input = devm_input_allocate_device(dev);
185	if (!input) {
186		dev_err(dev, "Failed to allocate input device.\n");
187		return -ENOMEM;
188	}
189
190	input_set_capability(input, EV_KEY, BTN_TOUCH);
191
192	input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
193	input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
194	input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
195
196	touchscreen_parse_properties(input, false, &eeti->props);
197
198	input->name = client->name;
199	input->id.bustype = BUS_I2C;
200	input->open = eeti_ts_open;
201	input->close = eeti_ts_close;
202
203	eeti->client = client;
204	eeti->input = input;
205
206	eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
207	if (IS_ERR(eeti->attn_gpio))
208		return PTR_ERR(eeti->attn_gpio);
209
210	i2c_set_clientdata(client, eeti);
211	input_set_drvdata(input, eeti);
212
213	error = devm_request_threaded_irq(dev, client->irq,
214					  NULL, eeti_ts_isr,
215					  IRQF_ONESHOT,
216					  client->name, eeti);
217	if (error) {
218		dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
219			error);
220		return error;
221	}
222
223	/*
224	 * Disable the device for now. It will be enabled once the
225	 * input device is opened.
226	 */
227	eeti_ts_stop(eeti);
228
229	error = input_register_device(input);
230	if (error)
231		return error;
232
233	return 0;
234}
235
236static int __maybe_unused eeti_ts_suspend(struct device *dev)
237{
238	struct i2c_client *client = to_i2c_client(dev);
239	struct eeti_ts *eeti = i2c_get_clientdata(client);
240	struct input_dev *input_dev = eeti->input;
241
242	mutex_lock(&input_dev->mutex);
243
244	if (input_dev->users)
245		eeti_ts_stop(eeti);
246
247	mutex_unlock(&input_dev->mutex);
248
249	if (device_may_wakeup(&client->dev))
250		enable_irq_wake(client->irq);
251
252	return 0;
253}
254
255static int __maybe_unused eeti_ts_resume(struct device *dev)
256{
257	struct i2c_client *client = to_i2c_client(dev);
258	struct eeti_ts *eeti = i2c_get_clientdata(client);
259	struct input_dev *input_dev = eeti->input;
260
261	if (device_may_wakeup(&client->dev))
262		disable_irq_wake(client->irq);
263
264	mutex_lock(&input_dev->mutex);
265
266	if (input_dev->users)
267		eeti_ts_start(eeti);
268
269	mutex_unlock(&input_dev->mutex);
270
271	return 0;
272}
273
274static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
275
276static const struct i2c_device_id eeti_ts_id[] = {
277	{ "eeti_ts", 0 },
278	{ }
279};
280MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
281
282#ifdef CONFIG_OF
283static const struct of_device_id of_eeti_ts_match[] = {
284	{ .compatible = "eeti,exc3000-i2c", },
285	{ }
286};
287#endif
288
289static struct i2c_driver eeti_ts_driver = {
290	.driver = {
291		.name = "eeti_ts",
292		.pm = &eeti_ts_pm,
293		.of_match_table = of_match_ptr(of_eeti_ts_match),
294	},
295	.probe = eeti_ts_probe,
296	.id_table = eeti_ts_id,
297};
298
299module_i2c_driver(eeti_ts_driver);
300
301MODULE_DESCRIPTION("EETI Touchscreen driver");
302MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
303MODULE_LICENSE("GPL");