1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for ELAN eKTF2127 i2c touchscreen controller
4  *
5  * For this driver the layout of the Chipone icn8318 i2c
6  * touchscreencontroller is used.
7  *
8  * Author:
9  * Michel Verlaan <michel.verl@gmail.com>
10  * Siebren Vroegindeweij <siebren.vroegindeweij@hotmail.com>
11  *
12  * Original chipone_icn8318 driver:
13  * Hans de Goede <hdegoede@redhat.com>
14  */
15 
16 #include <linux/gpio/consumer.h>
17 #include <linux/interrupt.h>
18 #include <linux/i2c.h>
19 #include <linux/input.h>
20 #include <linux/input/mt.h>
21 #include <linux/input/touchscreen.h>
22 #include <linux/module.h>
23 #include <linux/of.h>
24 #include <linux/delay.h>
25 
26 /* Packet header defines (first byte of data send / received) */
27 #define EKTF2127_NOISE			0x40
28 #define EKTF2127_RESPONSE		0x52
29 #define EKTF2127_REQUEST		0x53
30 #define EKTF2127_HELLO			0x55
31 #define EKTF2127_REPORT2		0x5a
32 #define EKTF2127_REPORT			0x5d
33 #define EKTF2127_CALIB_DONE		0x66
34 
35 /* Register defines (second byte of data send / received) */
36 #define EKTF2127_ENV_NOISY		0x41
37 #define EKTF2127_HEIGHT			0x60
38 #define EKTF2127_WIDTH			0x63
39 
40 /* 2 bytes header + 5 * 3 bytes coordinates + 3 bytes pressure info + footer */
41 #define EKTF2127_TOUCH_REPORT_SIZE	21
42 #define EKTF2127_MAX_TOUCHES		5
43 
44 struct ektf2127_ts {
45 	struct i2c_client *client;
46 	struct input_dev *input;
47 	struct gpio_desc *power_gpios;
48 	struct touchscreen_properties prop;
49 };
50 
51 static void ektf2127_parse_coordinates(const u8 *buf, unsigned int touch_count,
52 				       struct input_mt_pos *touches)
53 {
54 	int index = 0;
55 	int i;
56 
57 	for (i = 0; i < touch_count; i++) {
58 		index = 2 + i * 3;
59 
60 		touches[i].x = (buf[index] & 0x0f);
61 		touches[i].x <<= 8;
62 		touches[i].x |= buf[index + 2];
63 
64 		touches[i].y = (buf[index] & 0xf0);
65 		touches[i].y <<= 4;
66 		touches[i].y |= buf[index + 1];
67 	}
68 }
69 
70 static void ektf2127_report_event(struct ektf2127_ts *ts, const u8 *buf)
71 {
72 	struct input_mt_pos touches[EKTF2127_MAX_TOUCHES];
73 	int slots[EKTF2127_MAX_TOUCHES];
74 	unsigned int touch_count, i;
75 
76 	touch_count = buf[1] & 0x07;
77 	if (touch_count > EKTF2127_MAX_TOUCHES) {
78 		dev_err(&ts->client->dev,
79 			"Too many touches %d > %d\n",
80 			touch_count, EKTF2127_MAX_TOUCHES);
81 		touch_count = EKTF2127_MAX_TOUCHES;
82 	}
83 
84 	ektf2127_parse_coordinates(buf, touch_count, touches);
85 	input_mt_assign_slots(ts->input, slots, touches,
86 			      touch_count, 0);
87 
88 	for (i = 0; i < touch_count; i++) {
89 		input_mt_slot(ts->input, slots[i]);
90 		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
91 		touchscreen_report_pos(ts->input, &ts->prop,
92 				       touches[i].x, touches[i].y, true);
93 	}
94 
95 	input_mt_sync_frame(ts->input);
96 	input_sync(ts->input);
97 }
98 
99 static void ektf2127_report2_contact(struct ektf2127_ts *ts, int slot,
100 				     const u8 *buf, bool active)
101 {
102 	input_mt_slot(ts->input, slot);
103 	input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, active);
104 
105 	if (active) {
106 		int x = (buf[0] & 0xf0) << 4 | buf[1];
107 		int y = (buf[0] & 0x0f) << 8 | buf[2];
108 
109 		touchscreen_report_pos(ts->input, &ts->prop, x, y, true);
110 	}
111 }
112 
113 static void ektf2127_report2_event(struct ektf2127_ts *ts, const u8 *buf)
114 {
115 	ektf2127_report2_contact(ts, 0, &buf[1], !!(buf[7] & 2));
116 	ektf2127_report2_contact(ts, 1, &buf[4], !!(buf[7] & 4));
117 
118 	input_mt_sync_frame(ts->input);
119 	input_sync(ts->input);
120 }
121 
122 static irqreturn_t ektf2127_irq(int irq, void *dev_id)
123 {
124 	struct ektf2127_ts *ts = dev_id;
125 	struct device *dev = &ts->client->dev;
126 	char buf[EKTF2127_TOUCH_REPORT_SIZE];
127 	int ret;
128 
129 	ret = i2c_master_recv(ts->client, buf, EKTF2127_TOUCH_REPORT_SIZE);
130 	if (ret != EKTF2127_TOUCH_REPORT_SIZE) {
131 		dev_err(dev, "Error reading touch data: %d\n", ret);
132 		goto out;
133 	}
134 
135 	switch (buf[0]) {
136 	case EKTF2127_REPORT:
137 		ektf2127_report_event(ts, buf);
138 		break;
139 
140 	case EKTF2127_REPORT2:
141 		ektf2127_report2_event(ts, buf);
142 		break;
143 
144 	case EKTF2127_NOISE:
145 		if (buf[1] == EKTF2127_ENV_NOISY)
146 			dev_dbg(dev, "Environment is electrically noisy\n");
147 		break;
148 
149 	case EKTF2127_HELLO:
150 	case EKTF2127_CALIB_DONE:
151 		break;
152 
153 	default:
154 		dev_err(dev, "Unexpected packet header byte %#02x\n", buf[0]);
155 		break;
156 	}
157 
158 out:
159 	return IRQ_HANDLED;
160 }
161 
162 static int ektf2127_start(struct input_dev *dev)
163 {
164 	struct ektf2127_ts *ts = input_get_drvdata(dev);
165 
166 	enable_irq(ts->client->irq);
167 	gpiod_set_value_cansleep(ts->power_gpios, 1);
168 
169 	return 0;
170 }
171 
172 static void ektf2127_stop(struct input_dev *dev)
173 {
174 	struct ektf2127_ts *ts = input_get_drvdata(dev);
175 
176 	disable_irq(ts->client->irq);
177 	gpiod_set_value_cansleep(ts->power_gpios, 0);
178 }
179 
180 static int ektf2127_suspend(struct device *dev)
181 {
182 	struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
183 
184 	mutex_lock(&ts->input->mutex);
185 	if (input_device_enabled(ts->input))
186 		ektf2127_stop(ts->input);
187 	mutex_unlock(&ts->input->mutex);
188 
189 	return 0;
190 }
191 
192 static int ektf2127_resume(struct device *dev)
193 {
194 	struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
195 
196 	mutex_lock(&ts->input->mutex);
197 	if (input_device_enabled(ts->input))
198 		ektf2127_start(ts->input);
199 	mutex_unlock(&ts->input->mutex);
200 
201 	return 0;
202 }
203 
204 static DEFINE_SIMPLE_DEV_PM_OPS(ektf2127_pm_ops, ektf2127_suspend,
205 				ektf2127_resume);
206 
207 static int ektf2127_query_dimension(struct i2c_client *client, bool width)
208 {
209 	struct device *dev = &client->dev;
210 	const char *what = width ? "width" : "height";
211 	u8 what_code = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
212 	u8 buf[4];
213 	int ret;
214 	int error;
215 
216 	/* Request dimension */
217 	buf[0] = EKTF2127_REQUEST;
218 	buf[1] = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
219 	buf[2] = 0x00;
220 	buf[3] = 0x00;
221 	ret = i2c_master_send(client, buf, sizeof(buf));
222 	if (ret != sizeof(buf)) {
223 		error = ret < 0 ? ret : -EIO;
224 		dev_err(dev, "Failed to request %s: %d\n", what, error);
225 		return error;
226 	}
227 
228 	msleep(20);
229 
230 	/* Read response */
231 	ret = i2c_master_recv(client, buf, sizeof(buf));
232 	if (ret != sizeof(buf)) {
233 		error = ret < 0 ? ret : -EIO;
234 		dev_err(dev, "Failed to receive %s data: %d\n", what, error);
235 		return error;
236 	}
237 
238 	if (buf[0] != EKTF2127_RESPONSE || buf[1] != what_code) {
239 		dev_err(dev, "Unexpected %s data: %#02x %#02x\n",
240 			what, buf[0], buf[1]);
241 		return -EIO;
242 	}
243 
244 	return (((buf[3] & 0xf0) << 4) | buf[2]) - 1;
245 }
246 
247 static int ektf2127_probe(struct i2c_client *client)
248 {
249 	struct device *dev = &client->dev;
250 	struct ektf2127_ts *ts;
251 	struct input_dev *input;
252 	u8 buf[4];
253 	int max_x, max_y;
254 	int error;
255 
256 	if (!client->irq) {
257 		dev_err(dev, "Error no irq specified\n");
258 		return -EINVAL;
259 	}
260 
261 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
262 	if (!ts)
263 		return -ENOMEM;
264 
265 	/* This requests the gpio *and* turns on the touchscreen controller */
266 	ts->power_gpios = devm_gpiod_get(dev, "power", GPIOD_OUT_HIGH);
267 	if (IS_ERR(ts->power_gpios)) {
268 		error = PTR_ERR(ts->power_gpios);
269 		if (error != -EPROBE_DEFER)
270 			dev_err(dev, "Error getting power gpio: %d\n", error);
271 		return error;
272 	}
273 
274 	input = devm_input_allocate_device(dev);
275 	if (!input)
276 		return -ENOMEM;
277 
278 	input->name = client->name;
279 	input->id.bustype = BUS_I2C;
280 	input->open = ektf2127_start;
281 	input->close = ektf2127_stop;
282 
283 	ts->client = client;
284 
285 	/* Read hello (ignore result, depends on initial power state) */
286 	msleep(20);
287 	i2c_master_recv(ts->client, buf, sizeof(buf));
288 
289 	/* Read resolution from chip */
290 	max_x = ektf2127_query_dimension(client, true);
291 	if (max_x < 0)
292 		return max_x;
293 
294 	max_y = ektf2127_query_dimension(client, false);
295 	if (max_y < 0)
296 		return max_y;
297 
298 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_x, 0, 0);
299 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_y, 0, 0);
300 	touchscreen_parse_properties(input, true, &ts->prop);
301 
302 	error = input_mt_init_slots(input, EKTF2127_MAX_TOUCHES,
303 				    INPUT_MT_DIRECT |
304 					INPUT_MT_DROP_UNUSED |
305 					INPUT_MT_TRACK);
306 	if (error)
307 		return error;
308 
309 	ts->input = input;
310 	input_set_drvdata(input, ts);
311 
312 	error = devm_request_threaded_irq(dev, client->irq,
313 					  NULL, ektf2127_irq,
314 					  IRQF_ONESHOT, client->name, ts);
315 	if (error) {
316 		dev_err(dev, "Error requesting irq: %d\n", error);
317 		return error;
318 	}
319 
320 	/* Stop device till opened */
321 	ektf2127_stop(ts->input);
322 
323 	error = input_register_device(input);
324 	if (error)
325 		return error;
326 
327 	i2c_set_clientdata(client, ts);
328 
329 	return 0;
330 }
331 
332 #ifdef CONFIG_OF
333 static const struct of_device_id ektf2127_of_match[] = {
334 	{ .compatible = "elan,ektf2127" },
335 	{ .compatible = "elan,ektf2132" },
336 	{}
337 };
338 MODULE_DEVICE_TABLE(of, ektf2127_of_match);
339 #endif
340 
341 static const struct i2c_device_id ektf2127_i2c_id[] = {
342 	{ "ektf2127", 0 },
343 	{ "ektf2132", 0 },
344 	{}
345 };
346 MODULE_DEVICE_TABLE(i2c, ektf2127_i2c_id);
347 
348 static struct i2c_driver ektf2127_driver = {
349 	.driver = {
350 		.name	= "elan_ektf2127",
351 		.pm	= pm_sleep_ptr(&ektf2127_pm_ops),
352 		.of_match_table = of_match_ptr(ektf2127_of_match),
353 	},
354 	.probe = ektf2127_probe,
355 	.id_table = ektf2127_i2c_id,
356 };
357 module_i2c_driver(ektf2127_driver);
358 
359 MODULE_DESCRIPTION("ELAN eKTF2127/eKTF2132 I2C Touchscreen Driver");
360 MODULE_AUTHOR("Michel Verlaan, Siebren Vroegindeweij");
361 MODULE_LICENSE("GPL");
362