1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/delay.h>
3 #include <linux/gpio/consumer.h>
4 #include <linux/i2c.h>
5 #include <linux/input.h>
6 #include <linux/input/mt.h>
7 #include <linux/input/touchscreen.h>
8 #include <linux/interrupt.h>
9 #include <linux/module.h>
10 #include <linux/of_device.h>
11 #include <linux/sizes.h>
12 #include <linux/slab.h>
13 #include <asm/unaligned.h>
14 
15 #define ILI2XXX_POLL_PERIOD	20
16 
17 #define ILI210X_DATA_SIZE	64
18 #define ILI211X_DATA_SIZE	43
19 #define ILI251X_DATA_SIZE1	31
20 #define ILI251X_DATA_SIZE2	20
21 
22 /* Touchscreen commands */
23 #define REG_TOUCHDATA		0x10
24 #define REG_PANEL_INFO		0x20
25 #define REG_CALIBRATE		0xcc
26 
27 struct ili2xxx_chip {
28 	int (*read_reg)(struct i2c_client *client, u8 reg,
29 			void *buf, size_t len);
30 	int (*get_touch_data)(struct i2c_client *client, u8 *data);
31 	bool (*parse_touch_data)(const u8 *data, unsigned int finger,
32 				 unsigned int *x, unsigned int *y);
33 	bool (*continue_polling)(const u8 *data, bool touch);
34 	unsigned int max_touches;
35 	unsigned int resolution;
36 	bool has_calibrate_reg;
37 };
38 
39 struct ili210x {
40 	struct i2c_client *client;
41 	struct input_dev *input;
42 	struct gpio_desc *reset_gpio;
43 	struct touchscreen_properties prop;
44 	const struct ili2xxx_chip *chip;
45 	bool stop;
46 };
47 
48 static int ili210x_read_reg(struct i2c_client *client,
49 			    u8 reg, void *buf, size_t len)
50 {
51 	struct i2c_msg msg[] = {
52 		{
53 			.addr	= client->addr,
54 			.flags	= 0,
55 			.len	= 1,
56 			.buf	= &reg,
57 		},
58 		{
59 			.addr	= client->addr,
60 			.flags	= I2C_M_RD,
61 			.len	= len,
62 			.buf	= buf,
63 		}
64 	};
65 	int error, ret;
66 
67 	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
68 	if (ret != ARRAY_SIZE(msg)) {
69 		error = ret < 0 ? ret : -EIO;
70 		dev_err(&client->dev, "%s failed: %d\n", __func__, error);
71 		return error;
72 	}
73 
74 	return 0;
75 }
76 
77 static int ili210x_read_touch_data(struct i2c_client *client, u8 *data)
78 {
79 	return ili210x_read_reg(client, REG_TOUCHDATA,
80 				data, ILI210X_DATA_SIZE);
81 }
82 
83 static bool ili210x_touchdata_to_coords(const u8 *touchdata,
84 					unsigned int finger,
85 					unsigned int *x, unsigned int *y)
86 {
87 	if (touchdata[0] & BIT(finger))
88 		return false;
89 
90 	*x = get_unaligned_be16(touchdata + 1 + (finger * 4) + 0);
91 	*y = get_unaligned_be16(touchdata + 1 + (finger * 4) + 2);
92 
93 	return true;
94 }
95 
96 static bool ili210x_check_continue_polling(const u8 *data, bool touch)
97 {
98 	return data[0] & 0xf3;
99 }
100 
101 static const struct ili2xxx_chip ili210x_chip = {
102 	.read_reg		= ili210x_read_reg,
103 	.get_touch_data		= ili210x_read_touch_data,
104 	.parse_touch_data	= ili210x_touchdata_to_coords,
105 	.continue_polling	= ili210x_check_continue_polling,
106 	.max_touches		= 2,
107 	.has_calibrate_reg	= true,
108 };
109 
110 static int ili211x_read_touch_data(struct i2c_client *client, u8 *data)
111 {
112 	s16 sum = 0;
113 	int error;
114 	int ret;
115 	int i;
116 
117 	ret = i2c_master_recv(client, data, ILI211X_DATA_SIZE);
118 	if (ret != ILI211X_DATA_SIZE) {
119 		error = ret < 0 ? ret : -EIO;
120 		dev_err(&client->dev, "%s failed: %d\n", __func__, error);
121 		return error;
122 	}
123 
124 	/* This chip uses custom checksum at the end of data */
125 	for (i = 0; i < ILI211X_DATA_SIZE - 1; i++)
126 		sum = (sum + data[i]) & 0xff;
127 
128 	if ((-sum & 0xff) != data[ILI211X_DATA_SIZE - 1]) {
129 		dev_err(&client->dev,
130 			"CRC error (crc=0x%02x expected=0x%02x)\n",
131 			sum, data[ILI211X_DATA_SIZE - 1]);
132 		return -EIO;
133 	}
134 
135 	return 0;
136 }
137 
138 static bool ili211x_touchdata_to_coords(const u8 *touchdata,
139 					unsigned int finger,
140 					unsigned int *x, unsigned int *y)
141 {
142 	u32 data;
143 
144 	data = get_unaligned_be32(touchdata + 1 + (finger * 4) + 0);
145 	if (data == 0xffffffff)	/* Finger up */
146 		return false;
147 
148 	*x = ((touchdata[1 + (finger * 4) + 0] & 0xf0) << 4) |
149 	     touchdata[1 + (finger * 4) + 1];
150 	*y = ((touchdata[1 + (finger * 4) + 0] & 0x0f) << 8) |
151 	     touchdata[1 + (finger * 4) + 2];
152 
153 	return true;
154 }
155 
156 static bool ili211x_decline_polling(const u8 *data, bool touch)
157 {
158 	return false;
159 }
160 
161 static const struct ili2xxx_chip ili211x_chip = {
162 	.read_reg		= ili210x_read_reg,
163 	.get_touch_data		= ili211x_read_touch_data,
164 	.parse_touch_data	= ili211x_touchdata_to_coords,
165 	.continue_polling	= ili211x_decline_polling,
166 	.max_touches		= 10,
167 	.resolution		= 2048,
168 };
169 
170 static int ili251x_read_reg(struct i2c_client *client,
171 			    u8 reg, void *buf, size_t len)
172 {
173 	int error;
174 	int ret;
175 
176 	ret = i2c_master_send(client, &reg, 1);
177 	if (ret == 1) {
178 		usleep_range(5000, 5500);
179 
180 		ret = i2c_master_recv(client, buf, len);
181 		if (ret == len)
182 			return 0;
183 	}
184 
185 	error = ret < 0 ? ret : -EIO;
186 	dev_err(&client->dev, "%s failed: %d\n", __func__, error);
187 	return ret;
188 }
189 
190 static int ili251x_read_touch_data(struct i2c_client *client, u8 *data)
191 {
192 	int error;
193 
194 	error = ili251x_read_reg(client, REG_TOUCHDATA,
195 				 data, ILI251X_DATA_SIZE1);
196 	if (!error && data[0] == 2) {
197 		error = i2c_master_recv(client, data + ILI251X_DATA_SIZE1,
198 					ILI251X_DATA_SIZE2);
199 		if (error >= 0 && error != ILI251X_DATA_SIZE2)
200 			error = -EIO;
201 	}
202 
203 	return error;
204 }
205 
206 static bool ili251x_touchdata_to_coords(const u8 *touchdata,
207 					unsigned int finger,
208 					unsigned int *x, unsigned int *y)
209 {
210 	u16 val;
211 
212 	val = get_unaligned_be16(touchdata + 1 + (finger * 5) + 0);
213 	if (!(val & BIT(15)))	/* Touch indication */
214 		return false;
215 
216 	*x = val & 0x3fff;
217 	*y = get_unaligned_be16(touchdata + 1 + (finger * 5) + 2);
218 
219 	return true;
220 }
221 
222 static bool ili251x_check_continue_polling(const u8 *data, bool touch)
223 {
224 	return touch;
225 }
226 
227 static const struct ili2xxx_chip ili251x_chip = {
228 	.read_reg		= ili251x_read_reg,
229 	.get_touch_data		= ili251x_read_touch_data,
230 	.parse_touch_data	= ili251x_touchdata_to_coords,
231 	.continue_polling	= ili251x_check_continue_polling,
232 	.max_touches		= 10,
233 	.has_calibrate_reg	= true,
234 };
235 
236 static bool ili210x_report_events(struct ili210x *priv, u8 *touchdata)
237 {
238 	struct input_dev *input = priv->input;
239 	int i;
240 	bool contact = false, touch;
241 	unsigned int x = 0, y = 0;
242 
243 	for (i = 0; i < priv->chip->max_touches; i++) {
244 		touch = priv->chip->parse_touch_data(touchdata, i, &x, &y);
245 
246 		input_mt_slot(input, i);
247 		if (input_mt_report_slot_state(input, MT_TOOL_FINGER, touch)) {
248 			touchscreen_report_pos(input, &priv->prop, x, y, true);
249 			contact = true;
250 		}
251 	}
252 
253 	input_mt_report_pointer_emulation(input, false);
254 	input_sync(input);
255 
256 	return contact;
257 }
258 
259 static irqreturn_t ili210x_irq(int irq, void *irq_data)
260 {
261 	struct ili210x *priv = irq_data;
262 	struct i2c_client *client = priv->client;
263 	const struct ili2xxx_chip *chip = priv->chip;
264 	u8 touchdata[ILI210X_DATA_SIZE] = { 0 };
265 	bool keep_polling;
266 	bool touch;
267 	int error;
268 
269 	do {
270 		error = chip->get_touch_data(client, touchdata);
271 		if (error) {
272 			dev_err(&client->dev,
273 				"Unable to get touch data: %d\n", error);
274 			break;
275 		}
276 
277 		touch = ili210x_report_events(priv, touchdata);
278 		keep_polling = chip->continue_polling(touchdata, touch);
279 		if (keep_polling)
280 			msleep(ILI2XXX_POLL_PERIOD);
281 	} while (!priv->stop && keep_polling);
282 
283 	return IRQ_HANDLED;
284 }
285 
286 static ssize_t ili210x_calibrate(struct device *dev,
287 				 struct device_attribute *attr,
288 				 const char *buf, size_t count)
289 {
290 	struct i2c_client *client = to_i2c_client(dev);
291 	struct ili210x *priv = i2c_get_clientdata(client);
292 	unsigned long calibrate;
293 	int rc;
294 	u8 cmd = REG_CALIBRATE;
295 
296 	if (kstrtoul(buf, 10, &calibrate))
297 		return -EINVAL;
298 
299 	if (calibrate > 1)
300 		return -EINVAL;
301 
302 	if (calibrate) {
303 		rc = i2c_master_send(priv->client, &cmd, sizeof(cmd));
304 		if (rc != sizeof(cmd))
305 			return -EIO;
306 	}
307 
308 	return count;
309 }
310 static DEVICE_ATTR(calibrate, S_IWUSR, NULL, ili210x_calibrate);
311 
312 static struct attribute *ili210x_attributes[] = {
313 	&dev_attr_calibrate.attr,
314 	NULL,
315 };
316 
317 static umode_t ili210x_calibrate_visible(struct kobject *kobj,
318 					  struct attribute *attr, int index)
319 {
320 	struct device *dev = kobj_to_dev(kobj);
321 	struct i2c_client *client = to_i2c_client(dev);
322 	struct ili210x *priv = i2c_get_clientdata(client);
323 
324 	return priv->chip->has_calibrate_reg;
325 }
326 
327 static const struct attribute_group ili210x_attr_group = {
328 	.attrs = ili210x_attributes,
329 	.is_visible = ili210x_calibrate_visible,
330 };
331 
332 static void ili210x_power_down(void *data)
333 {
334 	struct gpio_desc *reset_gpio = data;
335 
336 	gpiod_set_value_cansleep(reset_gpio, 1);
337 }
338 
339 static void ili210x_stop(void *data)
340 {
341 	struct ili210x *priv = data;
342 
343 	/* Tell ISR to quit even if there is a contact. */
344 	priv->stop = true;
345 }
346 
347 static int ili210x_i2c_probe(struct i2c_client *client,
348 			     const struct i2c_device_id *id)
349 {
350 	struct device *dev = &client->dev;
351 	const struct ili2xxx_chip *chip;
352 	struct ili210x *priv;
353 	struct gpio_desc *reset_gpio;
354 	struct input_dev *input;
355 	int error;
356 	unsigned int max_xy;
357 
358 	dev_dbg(dev, "Probing for ILI210X I2C Touschreen driver");
359 
360 	chip = device_get_match_data(dev);
361 	if (!chip && id)
362 		chip = (const struct ili2xxx_chip *)id->driver_data;
363 	if (!chip) {
364 		dev_err(&client->dev, "unknown device model\n");
365 		return -ENODEV;
366 	}
367 
368 	if (client->irq <= 0) {
369 		dev_err(dev, "No IRQ!\n");
370 		return -EINVAL;
371 	}
372 
373 	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
374 	if (IS_ERR(reset_gpio))
375 		return PTR_ERR(reset_gpio);
376 
377 	if (reset_gpio) {
378 		error = devm_add_action_or_reset(dev, ili210x_power_down,
379 						 reset_gpio);
380 		if (error)
381 			return error;
382 
383 		usleep_range(50, 100);
384 		gpiod_set_value_cansleep(reset_gpio, 0);
385 		msleep(100);
386 	}
387 
388 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
389 	if (!priv)
390 		return -ENOMEM;
391 
392 	input = devm_input_allocate_device(dev);
393 	if (!input)
394 		return -ENOMEM;
395 
396 	priv->client = client;
397 	priv->input = input;
398 	priv->reset_gpio = reset_gpio;
399 	priv->chip = chip;
400 	i2c_set_clientdata(client, priv);
401 
402 	/* Setup input device */
403 	input->name = "ILI210x Touchscreen";
404 	input->id.bustype = BUS_I2C;
405 
406 	/* Multi touch */
407 	max_xy = (chip->resolution ?: SZ_64K) - 1;
408 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
409 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
410 	touchscreen_parse_properties(input, true, &priv->prop);
411 
412 	error = input_mt_init_slots(input, priv->chip->max_touches,
413 				    INPUT_MT_DIRECT);
414 	if (error) {
415 		dev_err(dev, "Unable to set up slots, err: %d\n", error);
416 		return error;
417 	}
418 
419 	error = devm_request_threaded_irq(dev, client->irq, NULL, ili210x_irq,
420 					  IRQF_ONESHOT, client->name, priv);
421 	if (error) {
422 		dev_err(dev, "Unable to request touchscreen IRQ, err: %d\n",
423 			error);
424 		return error;
425 	}
426 
427 	error = devm_add_action_or_reset(dev, ili210x_stop, priv);
428 	if (error)
429 		return error;
430 
431 	error = devm_device_add_group(dev, &ili210x_attr_group);
432 	if (error) {
433 		dev_err(dev, "Unable to create sysfs attributes, err: %d\n",
434 			error);
435 		return error;
436 	}
437 
438 	error = input_register_device(priv->input);
439 	if (error) {
440 		dev_err(dev, "Cannot register input device, err: %d\n", error);
441 		return error;
442 	}
443 
444 	return 0;
445 }
446 
447 static const struct i2c_device_id ili210x_i2c_id[] = {
448 	{ "ili210x", (long)&ili210x_chip },
449 	{ "ili2117", (long)&ili211x_chip },
450 	{ "ili251x", (long)&ili251x_chip },
451 	{ }
452 };
453 MODULE_DEVICE_TABLE(i2c, ili210x_i2c_id);
454 
455 static const struct of_device_id ili210x_dt_ids[] = {
456 	{ .compatible = "ilitek,ili210x", .data = &ili210x_chip },
457 	{ .compatible = "ilitek,ili2117", .data = &ili211x_chip },
458 	{ .compatible = "ilitek,ili251x", .data = &ili251x_chip },
459 	{ }
460 };
461 MODULE_DEVICE_TABLE(of, ili210x_dt_ids);
462 
463 static struct i2c_driver ili210x_ts_driver = {
464 	.driver = {
465 		.name = "ili210x_i2c",
466 		.of_match_table = ili210x_dt_ids,
467 	},
468 	.id_table = ili210x_i2c_id,
469 	.probe = ili210x_i2c_probe,
470 };
471 
472 module_i2c_driver(ili210x_ts_driver);
473 
474 MODULE_AUTHOR("Olivier Sobrie <olivier@sobrie.be>");
475 MODULE_DESCRIPTION("ILI210X I2C Touchscreen Driver");
476 MODULE_LICENSE("GPL");
477