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 <linux/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{
163	struct device *dev = &client->dev;
164	struct eeti_ts *eeti;
165	struct input_dev *input;
166	int error;
167
168	/*
169	 * In contrast to what's described in the datasheet, there seems
170	 * to be no way of probing the presence of that device using I2C
171	 * commands. So we need to blindly believe it is there, and wait
172	 * for interrupts to occur.
173	 */
174
175	eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
176	if (!eeti) {
177		dev_err(dev, "failed to allocate driver data\n");
178		return -ENOMEM;
179	}
180
181	mutex_init(&eeti->mutex);
182
183	input = devm_input_allocate_device(dev);
184	if (!input) {
185		dev_err(dev, "Failed to allocate input device.\n");
186		return -ENOMEM;
187	}
188
189	input_set_capability(input, EV_KEY, BTN_TOUCH);
190
191	input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
192	input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
193	input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
194
195	touchscreen_parse_properties(input, false, &eeti->props);
196
197	input->name = client->name;
198	input->id.bustype = BUS_I2C;
199	input->open = eeti_ts_open;
200	input->close = eeti_ts_close;
201
202	eeti->client = client;
203	eeti->input = input;
204
205	eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
206	if (IS_ERR(eeti->attn_gpio))
207		return PTR_ERR(eeti->attn_gpio);
208
209	i2c_set_clientdata(client, eeti);
210	input_set_drvdata(input, eeti);
211
212	error = devm_request_threaded_irq(dev, client->irq,
213					  NULL, eeti_ts_isr,
214					  IRQF_ONESHOT,
215					  client->name, eeti);
216	if (error) {
217		dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
218			error);
219		return error;
220	}
221
222	/*
223	 * Disable the device for now. It will be enabled once the
224	 * input device is opened.
225	 */
226	eeti_ts_stop(eeti);
227
228	error = input_register_device(input);
229	if (error)
230		return error;
231
232	return 0;
233}
234
235static int eeti_ts_suspend(struct device *dev)
236{
237	struct i2c_client *client = to_i2c_client(dev);
238	struct eeti_ts *eeti = i2c_get_clientdata(client);
239	struct input_dev *input_dev = eeti->input;
240
241	mutex_lock(&input_dev->mutex);
242
243	if (input_device_enabled(input_dev))
244		eeti_ts_stop(eeti);
245
246	mutex_unlock(&input_dev->mutex);
247
248	if (device_may_wakeup(&client->dev))
249		enable_irq_wake(client->irq);
250
251	return 0;
252}
253
254static int eeti_ts_resume(struct device *dev)
255{
256	struct i2c_client *client = to_i2c_client(dev);
257	struct eeti_ts *eeti = i2c_get_clientdata(client);
258	struct input_dev *input_dev = eeti->input;
259
260	if (device_may_wakeup(&client->dev))
261		disable_irq_wake(client->irq);
262
263	mutex_lock(&input_dev->mutex);
264
265	if (input_device_enabled(input_dev))
266		eeti_ts_start(eeti);
267
268	mutex_unlock(&input_dev->mutex);
269
270	return 0;
271}
272
273static DEFINE_SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
274
275static const struct i2c_device_id eeti_ts_id[] = {
276	{ "eeti_ts" },
277	{ }
278};
279MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
280
281#ifdef CONFIG_OF
282static const struct of_device_id of_eeti_ts_match[] = {
283	{ .compatible = "eeti,exc3000-i2c", },
284	{ }
285};
286#endif
287
288static struct i2c_driver eeti_ts_driver = {
289	.driver = {
290		.name = "eeti_ts",
291		.pm = pm_sleep_ptr(&eeti_ts_pm),
292		.of_match_table = of_match_ptr(of_eeti_ts_match),
293	},
294	.probe = eeti_ts_probe,
295	.id_table = eeti_ts_id,
296};
297
298module_i2c_driver(eeti_ts_driver);
299
300MODULE_DESCRIPTION("EETI Touchscreen driver");
301MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
302MODULE_LICENSE("GPL");

  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{
163	struct device *dev = &client->dev;
164	struct eeti_ts *eeti;
165	struct input_dev *input;
166	int error;
167
168	/*
169	 * In contrast to what's described in the datasheet, there seems
170	 * to be no way of probing the presence of that device using I2C
171	 * commands. So we need to blindly believe it is there, and wait
172	 * for interrupts to occur.
173	 */
174
175	eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
176	if (!eeti) {
177		dev_err(dev, "failed to allocate driver data\n");
178		return -ENOMEM;
179	}
180
181	mutex_init(&eeti->mutex);
182
183	input = devm_input_allocate_device(dev);
184	if (!input) {
185		dev_err(dev, "Failed to allocate input device.\n");
186		return -ENOMEM;
187	}
188
189	input_set_capability(input, EV_KEY, BTN_TOUCH);
190
191	input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
192	input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
193	input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
194
195	touchscreen_parse_properties(input, false, &eeti->props);
196
197	input->name = client->name;
198	input->id.bustype = BUS_I2C;
199	input->open = eeti_ts_open;
200	input->close = eeti_ts_close;
201
202	eeti->client = client;
203	eeti->input = input;
204
205	eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
206	if (IS_ERR(eeti->attn_gpio))
207		return PTR_ERR(eeti->attn_gpio);
208
209	i2c_set_clientdata(client, eeti);
210	input_set_drvdata(input, eeti);
211
212	error = devm_request_threaded_irq(dev, client->irq,
213					  NULL, eeti_ts_isr,
214					  IRQF_ONESHOT,
215					  client->name, eeti);
216	if (error) {
217		dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
218			error);
219		return error;
220	}
221
222	/*
223	 * Disable the device for now. It will be enabled once the
224	 * input device is opened.
225	 */
226	eeti_ts_stop(eeti);
227
228	error = input_register_device(input);
229	if (error)
230		return error;
231
232	return 0;
233}
234
235static int eeti_ts_suspend(struct device *dev)
236{
237	struct i2c_client *client = to_i2c_client(dev);
238	struct eeti_ts *eeti = i2c_get_clientdata(client);
239	struct input_dev *input_dev = eeti->input;
240
241	mutex_lock(&input_dev->mutex);
242
243	if (input_device_enabled(input_dev))
244		eeti_ts_stop(eeti);
245
246	mutex_unlock(&input_dev->mutex);
247
248	if (device_may_wakeup(&client->dev))
249		enable_irq_wake(client->irq);
250
251	return 0;
252}
253
254static int eeti_ts_resume(struct device *dev)
255{
256	struct i2c_client *client = to_i2c_client(dev);
257	struct eeti_ts *eeti = i2c_get_clientdata(client);
258	struct input_dev *input_dev = eeti->input;
259
260	if (device_may_wakeup(&client->dev))
261		disable_irq_wake(client->irq);
262
263	mutex_lock(&input_dev->mutex);
264
265	if (input_device_enabled(input_dev))
266		eeti_ts_start(eeti);
267
268	mutex_unlock(&input_dev->mutex);
269
270	return 0;
271}
272
273static DEFINE_SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
274
275static const struct i2c_device_id eeti_ts_id[] = {
276	{ "eeti_ts", 0 },
277	{ }
278};
279MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
280
281#ifdef CONFIG_OF
282static const struct of_device_id of_eeti_ts_match[] = {
283	{ .compatible = "eeti,exc3000-i2c", },
284	{ }
285};
286#endif
287
288static struct i2c_driver eeti_ts_driver = {
289	.driver = {
290		.name = "eeti_ts",
291		.pm = pm_sleep_ptr(&eeti_ts_pm),
292		.of_match_table = of_match_ptr(of_eeti_ts_match),
293	},
294	.probe = eeti_ts_probe,
295	.id_table = eeti_ts_id,
296};
297
298module_i2c_driver(eeti_ts_driver);
299
300MODULE_DESCRIPTION("EETI Touchscreen driver");
301MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
302MODULE_LICENSE("GPL");