xref: /linux/drivers/input/touchscreen/iqs5xx.c (revision 4fd18fc38757217c746aa063ba9e4729814dc737)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Azoteq IQS550/572/525 Trackpad/Touchscreen Controller
4  *
5  * Copyright (C) 2018
6  * Author: Jeff LaBundy <jeff@labundy.com>
7  *
8  * These devices require firmware exported from a PC-based configuration tool
9  * made available by the vendor. Firmware files may be pushed to the device's
10  * nonvolatile memory by writing the filename to the 'fw_file' sysfs control.
11  *
12  * Link to PC-based configuration tool and data sheet: http://www.azoteq.com/
13  */
14 
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/firmware.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/i2c.h>
21 #include <linux/input.h>
22 #include <linux/input/mt.h>
23 #include <linux/input/touchscreen.h>
24 #include <linux/interrupt.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/of_device.h>
28 #include <linux/slab.h>
29 #include <asm/unaligned.h>
30 
31 #define IQS5XX_FW_FILE_LEN	64
32 #define IQS5XX_NUM_RETRIES	10
33 #define IQS5XX_NUM_POINTS	256
34 #define IQS5XX_NUM_CONTACTS	5
35 #define IQS5XX_WR_BYTES_MAX	2
36 
37 #define IQS5XX_PROD_NUM_IQS550	40
38 #define IQS5XX_PROD_NUM_IQS572	58
39 #define IQS5XX_PROD_NUM_IQS525	52
40 #define IQS5XX_PROJ_NUM_A000	0
41 #define IQS5XX_PROJ_NUM_B000	15
42 #define IQS5XX_MAJOR_VER_MIN	2
43 
44 #define IQS5XX_RESUME		0x00
45 #define IQS5XX_SUSPEND		0x01
46 
47 #define IQS5XX_SW_INPUT_EVENT	0x10
48 #define IQS5XX_SETUP_COMPLETE	0x40
49 #define IQS5XX_EVENT_MODE	0x01
50 #define IQS5XX_TP_EVENT		0x04
51 
52 #define IQS5XX_FLIP_X		0x01
53 #define IQS5XX_FLIP_Y		0x02
54 #define IQS5XX_SWITCH_XY_AXIS	0x04
55 
56 #define IQS5XX_PROD_NUM		0x0000
57 #define IQS5XX_ABS_X		0x0016
58 #define IQS5XX_ABS_Y		0x0018
59 #define IQS5XX_SYS_CTRL0	0x0431
60 #define IQS5XX_SYS_CTRL1	0x0432
61 #define IQS5XX_SYS_CFG0		0x058E
62 #define IQS5XX_SYS_CFG1		0x058F
63 #define IQS5XX_TOTAL_RX		0x063D
64 #define IQS5XX_TOTAL_TX		0x063E
65 #define IQS5XX_XY_CFG0		0x0669
66 #define IQS5XX_X_RES		0x066E
67 #define IQS5XX_Y_RES		0x0670
68 #define IQS5XX_CHKSM		0x83C0
69 #define IQS5XX_APP		0x8400
70 #define IQS5XX_CSTM		0xBE00
71 #define IQS5XX_PMAP_END		0xBFFF
72 #define IQS5XX_END_COMM		0xEEEE
73 
74 #define IQS5XX_CHKSM_LEN	(IQS5XX_APP - IQS5XX_CHKSM)
75 #define IQS5XX_APP_LEN		(IQS5XX_CSTM - IQS5XX_APP)
76 #define IQS5XX_CSTM_LEN		(IQS5XX_PMAP_END + 1 - IQS5XX_CSTM)
77 #define IQS5XX_PMAP_LEN		(IQS5XX_PMAP_END + 1 - IQS5XX_CHKSM)
78 
79 #define IQS5XX_REC_HDR_LEN	4
80 #define IQS5XX_REC_LEN_MAX	255
81 #define IQS5XX_REC_TYPE_DATA	0x00
82 #define IQS5XX_REC_TYPE_EOF	0x01
83 
84 #define IQS5XX_BL_ADDR_MASK	0x40
85 #define IQS5XX_BL_CMD_VER	0x00
86 #define IQS5XX_BL_CMD_READ	0x01
87 #define IQS5XX_BL_CMD_EXEC	0x02
88 #define IQS5XX_BL_CMD_CRC	0x03
89 #define IQS5XX_BL_BLK_LEN_MAX	64
90 #define IQS5XX_BL_ID		0x0200
91 #define IQS5XX_BL_STATUS_RESET	0x00
92 #define IQS5XX_BL_STATUS_AVAIL	0xA5
93 #define IQS5XX_BL_STATUS_NONE	0xEE
94 #define IQS5XX_BL_CRC_PASS	0x00
95 #define IQS5XX_BL_CRC_FAIL	0x01
96 #define IQS5XX_BL_ATTEMPTS	3
97 
98 struct iqs5xx_private {
99 	struct i2c_client *client;
100 	struct input_dev *input;
101 	struct gpio_desc *reset_gpio;
102 	struct mutex lock;
103 	u8 bl_status;
104 };
105 
106 struct iqs5xx_dev_id_info {
107 	__be16 prod_num;
108 	__be16 proj_num;
109 	u8 major_ver;
110 	u8 minor_ver;
111 	u8 bl_status;
112 } __packed;
113 
114 struct iqs5xx_ihex_rec {
115 	char start;
116 	char len[2];
117 	char addr[4];
118 	char type[2];
119 	char data[2];
120 } __packed;
121 
122 struct iqs5xx_touch_data {
123 	__be16 abs_x;
124 	__be16 abs_y;
125 	__be16 strength;
126 	u8 area;
127 } __packed;
128 
129 static int iqs5xx_read_burst(struct i2c_client *client,
130 			     u16 reg, void *val, u16 len)
131 {
132 	__be16 reg_buf = cpu_to_be16(reg);
133 	int ret, i;
134 	struct i2c_msg msg[] = {
135 		{
136 			.addr = client->addr,
137 			.flags = 0,
138 			.len = sizeof(reg_buf),
139 			.buf = (u8 *)&reg_buf,
140 		},
141 		{
142 			.addr = client->addr,
143 			.flags = I2C_M_RD,
144 			.len = len,
145 			.buf = (u8 *)val,
146 		},
147 	};
148 
149 	/*
150 	 * The first addressing attempt outside of a communication window fails
151 	 * and must be retried, after which the device clock stretches until it
152 	 * is available.
153 	 */
154 	for (i = 0; i < IQS5XX_NUM_RETRIES; i++) {
155 		ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
156 		if (ret == ARRAY_SIZE(msg))
157 			return 0;
158 
159 		usleep_range(200, 300);
160 	}
161 
162 	if (ret >= 0)
163 		ret = -EIO;
164 
165 	dev_err(&client->dev, "Failed to read from address 0x%04X: %d\n",
166 		reg, ret);
167 
168 	return ret;
169 }
170 
171 static int iqs5xx_read_word(struct i2c_client *client, u16 reg, u16 *val)
172 {
173 	__be16 val_buf;
174 	int error;
175 
176 	error = iqs5xx_read_burst(client, reg, &val_buf, sizeof(val_buf));
177 	if (error)
178 		return error;
179 
180 	*val = be16_to_cpu(val_buf);
181 
182 	return 0;
183 }
184 
185 static int iqs5xx_read_byte(struct i2c_client *client, u16 reg, u8 *val)
186 {
187 	return iqs5xx_read_burst(client, reg, val, sizeof(*val));
188 }
189 
190 static int iqs5xx_write_burst(struct i2c_client *client,
191 			      u16 reg, const void *val, u16 len)
192 {
193 	int ret, i;
194 	u16 mlen = sizeof(reg) + len;
195 	u8 mbuf[sizeof(reg) + IQS5XX_WR_BYTES_MAX];
196 
197 	if (len > IQS5XX_WR_BYTES_MAX)
198 		return -EINVAL;
199 
200 	put_unaligned_be16(reg, mbuf);
201 	memcpy(mbuf + sizeof(reg), val, len);
202 
203 	/*
204 	 * The first addressing attempt outside of a communication window fails
205 	 * and must be retried, after which the device clock stretches until it
206 	 * is available.
207 	 */
208 	for (i = 0; i < IQS5XX_NUM_RETRIES; i++) {
209 		ret = i2c_master_send(client, mbuf, mlen);
210 		if (ret == mlen)
211 			return 0;
212 
213 		usleep_range(200, 300);
214 	}
215 
216 	if (ret >= 0)
217 		ret = -EIO;
218 
219 	dev_err(&client->dev, "Failed to write to address 0x%04X: %d\n",
220 		reg, ret);
221 
222 	return ret;
223 }
224 
225 static int iqs5xx_write_word(struct i2c_client *client, u16 reg, u16 val)
226 {
227 	__be16 val_buf = cpu_to_be16(val);
228 
229 	return iqs5xx_write_burst(client, reg, &val_buf, sizeof(val_buf));
230 }
231 
232 static int iqs5xx_write_byte(struct i2c_client *client, u16 reg, u8 val)
233 {
234 	return iqs5xx_write_burst(client, reg, &val, sizeof(val));
235 }
236 
237 static void iqs5xx_reset(struct i2c_client *client)
238 {
239 	struct iqs5xx_private *iqs5xx = i2c_get_clientdata(client);
240 
241 	gpiod_set_value_cansleep(iqs5xx->reset_gpio, 1);
242 	usleep_range(200, 300);
243 
244 	gpiod_set_value_cansleep(iqs5xx->reset_gpio, 0);
245 }
246 
247 static int iqs5xx_bl_cmd(struct i2c_client *client, u8 bl_cmd, u16 bl_addr)
248 {
249 	struct i2c_msg msg;
250 	int ret;
251 	u8 mbuf[sizeof(bl_cmd) + sizeof(bl_addr)];
252 
253 	msg.addr = client->addr ^ IQS5XX_BL_ADDR_MASK;
254 	msg.flags = 0;
255 	msg.len = sizeof(bl_cmd);
256 	msg.buf = mbuf;
257 
258 	*mbuf = bl_cmd;
259 
260 	switch (bl_cmd) {
261 	case IQS5XX_BL_CMD_VER:
262 	case IQS5XX_BL_CMD_CRC:
263 	case IQS5XX_BL_CMD_EXEC:
264 		break;
265 	case IQS5XX_BL_CMD_READ:
266 		msg.len += sizeof(bl_addr);
267 		put_unaligned_be16(bl_addr, mbuf + sizeof(bl_cmd));
268 		break;
269 	default:
270 		return -EINVAL;
271 	}
272 
273 	ret = i2c_transfer(client->adapter, &msg, 1);
274 	if (ret != 1)
275 		goto msg_fail;
276 
277 	switch (bl_cmd) {
278 	case IQS5XX_BL_CMD_VER:
279 		msg.len = sizeof(u16);
280 		break;
281 	case IQS5XX_BL_CMD_CRC:
282 		msg.len = sizeof(u8);
283 		/*
284 		 * This delay saves the bus controller the trouble of having to
285 		 * tolerate a relatively long clock-stretching period while the
286 		 * CRC is calculated.
287 		 */
288 		msleep(50);
289 		break;
290 	case IQS5XX_BL_CMD_EXEC:
291 		usleep_range(10000, 10100);
292 		fallthrough;
293 	default:
294 		return 0;
295 	}
296 
297 	msg.flags = I2C_M_RD;
298 
299 	ret = i2c_transfer(client->adapter, &msg, 1);
300 	if (ret != 1)
301 		goto msg_fail;
302 
303 	if (bl_cmd == IQS5XX_BL_CMD_VER &&
304 	    get_unaligned_be16(mbuf) != IQS5XX_BL_ID) {
305 		dev_err(&client->dev, "Unrecognized bootloader ID: 0x%04X\n",
306 			get_unaligned_be16(mbuf));
307 		return -EINVAL;
308 	}
309 
310 	if (bl_cmd == IQS5XX_BL_CMD_CRC && *mbuf != IQS5XX_BL_CRC_PASS) {
311 		dev_err(&client->dev, "Bootloader CRC failed\n");
312 		return -EIO;
313 	}
314 
315 	return 0;
316 
317 msg_fail:
318 	if (ret >= 0)
319 		ret = -EIO;
320 
321 	if (bl_cmd != IQS5XX_BL_CMD_VER)
322 		dev_err(&client->dev,
323 			"Unsuccessful bootloader command 0x%02X: %d\n",
324 			bl_cmd, ret);
325 
326 	return ret;
327 }
328 
329 static int iqs5xx_bl_open(struct i2c_client *client)
330 {
331 	int error, i, j;
332 
333 	/*
334 	 * The device opens a bootloader polling window for 2 ms following the
335 	 * release of reset. If the host cannot establish communication during
336 	 * this time frame, it must cycle reset again.
337 	 */
338 	for (i = 0; i < IQS5XX_BL_ATTEMPTS; i++) {
339 		iqs5xx_reset(client);
340 
341 		for (j = 0; j < IQS5XX_NUM_RETRIES; j++) {
342 			error = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_VER, 0);
343 			if (!error || error == -EINVAL)
344 				return error;
345 		}
346 	}
347 
348 	dev_err(&client->dev, "Failed to open bootloader: %d\n", error);
349 
350 	return error;
351 }
352 
353 static int iqs5xx_bl_write(struct i2c_client *client,
354 			   u16 bl_addr, u8 *pmap_data, u16 pmap_len)
355 {
356 	struct i2c_msg msg;
357 	int ret, i;
358 	u8 mbuf[sizeof(bl_addr) + IQS5XX_BL_BLK_LEN_MAX];
359 
360 	if (pmap_len % IQS5XX_BL_BLK_LEN_MAX)
361 		return -EINVAL;
362 
363 	msg.addr = client->addr ^ IQS5XX_BL_ADDR_MASK;
364 	msg.flags = 0;
365 	msg.len = sizeof(mbuf);
366 	msg.buf = mbuf;
367 
368 	for (i = 0; i < pmap_len; i += IQS5XX_BL_BLK_LEN_MAX) {
369 		put_unaligned_be16(bl_addr + i, mbuf);
370 		memcpy(mbuf + sizeof(bl_addr), pmap_data + i,
371 		       sizeof(mbuf) - sizeof(bl_addr));
372 
373 		ret = i2c_transfer(client->adapter, &msg, 1);
374 		if (ret != 1)
375 			goto msg_fail;
376 
377 		usleep_range(10000, 10100);
378 	}
379 
380 	return 0;
381 
382 msg_fail:
383 	if (ret >= 0)
384 		ret = -EIO;
385 
386 	dev_err(&client->dev, "Failed to write block at address 0x%04X: %d\n",
387 		bl_addr + i, ret);
388 
389 	return ret;
390 }
391 
392 static int iqs5xx_bl_verify(struct i2c_client *client,
393 			    u16 bl_addr, u8 *pmap_data, u16 pmap_len)
394 {
395 	struct i2c_msg msg;
396 	int ret, i;
397 	u8 bl_data[IQS5XX_BL_BLK_LEN_MAX];
398 
399 	if (pmap_len % IQS5XX_BL_BLK_LEN_MAX)
400 		return -EINVAL;
401 
402 	msg.addr = client->addr ^ IQS5XX_BL_ADDR_MASK;
403 	msg.flags = I2C_M_RD;
404 	msg.len = sizeof(bl_data);
405 	msg.buf = bl_data;
406 
407 	for (i = 0; i < pmap_len; i += IQS5XX_BL_BLK_LEN_MAX) {
408 		ret = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_READ, bl_addr + i);
409 		if (ret)
410 			return ret;
411 
412 		ret = i2c_transfer(client->adapter, &msg, 1);
413 		if (ret != 1)
414 			goto msg_fail;
415 
416 		if (memcmp(bl_data, pmap_data + i, sizeof(bl_data))) {
417 			dev_err(&client->dev,
418 				"Failed to verify block at address 0x%04X\n",
419 				bl_addr + i);
420 			return -EIO;
421 		}
422 	}
423 
424 	return 0;
425 
426 msg_fail:
427 	if (ret >= 0)
428 		ret = -EIO;
429 
430 	dev_err(&client->dev, "Failed to read block at address 0x%04X: %d\n",
431 		bl_addr + i, ret);
432 
433 	return ret;
434 }
435 
436 static int iqs5xx_set_state(struct i2c_client *client, u8 state)
437 {
438 	struct iqs5xx_private *iqs5xx = i2c_get_clientdata(client);
439 	int error1, error2;
440 
441 	if (iqs5xx->bl_status == IQS5XX_BL_STATUS_RESET)
442 		return 0;
443 
444 	mutex_lock(&iqs5xx->lock);
445 
446 	/*
447 	 * Addressing the device outside of a communication window prompts it
448 	 * to assert the RDY output, so disable the interrupt line to prevent
449 	 * the handler from servicing a false interrupt.
450 	 */
451 	disable_irq(client->irq);
452 
453 	error1 = iqs5xx_write_byte(client, IQS5XX_SYS_CTRL1, state);
454 	error2 = iqs5xx_write_byte(client, IQS5XX_END_COMM, 0);
455 
456 	usleep_range(50, 100);
457 	enable_irq(client->irq);
458 
459 	mutex_unlock(&iqs5xx->lock);
460 
461 	if (error1)
462 		return error1;
463 
464 	return error2;
465 }
466 
467 static int iqs5xx_open(struct input_dev *input)
468 {
469 	struct iqs5xx_private *iqs5xx = input_get_drvdata(input);
470 
471 	return iqs5xx_set_state(iqs5xx->client, IQS5XX_RESUME);
472 }
473 
474 static void iqs5xx_close(struct input_dev *input)
475 {
476 	struct iqs5xx_private *iqs5xx = input_get_drvdata(input);
477 
478 	iqs5xx_set_state(iqs5xx->client, IQS5XX_SUSPEND);
479 }
480 
481 static int iqs5xx_axis_init(struct i2c_client *client)
482 {
483 	struct iqs5xx_private *iqs5xx = i2c_get_clientdata(client);
484 	struct touchscreen_properties prop;
485 	struct input_dev *input;
486 	int error;
487 	u16 max_x, max_x_hw;
488 	u16 max_y, max_y_hw;
489 	u8 val;
490 
491 	if (!iqs5xx->input) {
492 		input = devm_input_allocate_device(&client->dev);
493 		if (!input)
494 			return -ENOMEM;
495 
496 		input->name = client->name;
497 		input->id.bustype = BUS_I2C;
498 		input->open = iqs5xx_open;
499 		input->close = iqs5xx_close;
500 
501 		input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
502 		input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
503 		input_set_capability(input, EV_ABS, ABS_MT_PRESSURE);
504 
505 		input_set_drvdata(input, iqs5xx);
506 		iqs5xx->input = input;
507 	}
508 
509 	touchscreen_parse_properties(iqs5xx->input, true, &prop);
510 
511 	error = iqs5xx_read_byte(client, IQS5XX_TOTAL_RX, &val);
512 	if (error)
513 		return error;
514 	max_x_hw = (val - 1) * IQS5XX_NUM_POINTS;
515 
516 	error = iqs5xx_read_byte(client, IQS5XX_TOTAL_TX, &val);
517 	if (error)
518 		return error;
519 	max_y_hw = (val - 1) * IQS5XX_NUM_POINTS;
520 
521 	error = iqs5xx_read_byte(client, IQS5XX_XY_CFG0, &val);
522 	if (error)
523 		return error;
524 
525 	if (val & IQS5XX_SWITCH_XY_AXIS)
526 		swap(max_x_hw, max_y_hw);
527 
528 	if (prop.swap_x_y)
529 		val ^= IQS5XX_SWITCH_XY_AXIS;
530 
531 	if (prop.invert_x)
532 		val ^= prop.swap_x_y ? IQS5XX_FLIP_Y : IQS5XX_FLIP_X;
533 
534 	if (prop.invert_y)
535 		val ^= prop.swap_x_y ? IQS5XX_FLIP_X : IQS5XX_FLIP_Y;
536 
537 	error = iqs5xx_write_byte(client, IQS5XX_XY_CFG0, val);
538 	if (error)
539 		return error;
540 
541 	if (prop.max_x > max_x_hw) {
542 		dev_err(&client->dev, "Invalid maximum x-coordinate: %u > %u\n",
543 			prop.max_x, max_x_hw);
544 		return -EINVAL;
545 	} else if (prop.max_x == 0) {
546 		error = iqs5xx_read_word(client, IQS5XX_X_RES, &max_x);
547 		if (error)
548 			return error;
549 
550 		input_abs_set_max(iqs5xx->input,
551 				  prop.swap_x_y ? ABS_MT_POSITION_Y :
552 						  ABS_MT_POSITION_X,
553 				  max_x);
554 	} else {
555 		max_x = (u16)prop.max_x;
556 	}
557 
558 	if (prop.max_y > max_y_hw) {
559 		dev_err(&client->dev, "Invalid maximum y-coordinate: %u > %u\n",
560 			prop.max_y, max_y_hw);
561 		return -EINVAL;
562 	} else if (prop.max_y == 0) {
563 		error = iqs5xx_read_word(client, IQS5XX_Y_RES, &max_y);
564 		if (error)
565 			return error;
566 
567 		input_abs_set_max(iqs5xx->input,
568 				  prop.swap_x_y ? ABS_MT_POSITION_X :
569 						  ABS_MT_POSITION_Y,
570 				  max_y);
571 	} else {
572 		max_y = (u16)prop.max_y;
573 	}
574 
575 	/*
576 	 * Write horizontal and vertical resolution to the device in case its
577 	 * original defaults were overridden or swapped as per the properties
578 	 * specified in the device tree.
579 	 */
580 	error = iqs5xx_write_word(client,
581 				  prop.swap_x_y ? IQS5XX_Y_RES : IQS5XX_X_RES,
582 				  max_x);
583 	if (error)
584 		return error;
585 
586 	error = iqs5xx_write_word(client,
587 				  prop.swap_x_y ? IQS5XX_X_RES : IQS5XX_Y_RES,
588 				  max_y);
589 	if (error)
590 		return error;
591 
592 	error = input_mt_init_slots(iqs5xx->input, IQS5XX_NUM_CONTACTS,
593 				    INPUT_MT_DIRECT);
594 	if (error)
595 		dev_err(&client->dev, "Failed to initialize slots: %d\n",
596 			error);
597 
598 	return error;
599 }
600 
601 static int iqs5xx_dev_init(struct i2c_client *client)
602 {
603 	struct iqs5xx_private *iqs5xx = i2c_get_clientdata(client);
604 	struct iqs5xx_dev_id_info *dev_id_info;
605 	int error;
606 	u8 val;
607 	u8 buf[sizeof(*dev_id_info) + 1];
608 
609 	error = iqs5xx_read_burst(client, IQS5XX_PROD_NUM,
610 				  &buf[1], sizeof(*dev_id_info));
611 	if (error)
612 		return iqs5xx_bl_open(client);
613 
614 	/*
615 	 * A000 and B000 devices use 8-bit and 16-bit addressing, respectively.
616 	 * Querying an A000 device's version information with 16-bit addressing
617 	 * gives the appearance that the data is shifted by one byte; a nonzero
618 	 * leading array element suggests this could be the case (in which case
619 	 * the missing zero is prepended).
620 	 */
621 	buf[0] = 0;
622 	dev_id_info = (struct iqs5xx_dev_id_info *)&buf[(buf[1] > 0) ? 0 : 1];
623 
624 	switch (be16_to_cpu(dev_id_info->prod_num)) {
625 	case IQS5XX_PROD_NUM_IQS550:
626 	case IQS5XX_PROD_NUM_IQS572:
627 	case IQS5XX_PROD_NUM_IQS525:
628 		break;
629 	default:
630 		dev_err(&client->dev, "Unrecognized product number: %u\n",
631 			be16_to_cpu(dev_id_info->prod_num));
632 		return -EINVAL;
633 	}
634 
635 	switch (be16_to_cpu(dev_id_info->proj_num)) {
636 	case IQS5XX_PROJ_NUM_A000:
637 		dev_err(&client->dev, "Unsupported project number: %u\n",
638 			be16_to_cpu(dev_id_info->proj_num));
639 		return iqs5xx_bl_open(client);
640 	case IQS5XX_PROJ_NUM_B000:
641 		break;
642 	default:
643 		dev_err(&client->dev, "Unrecognized project number: %u\n",
644 			be16_to_cpu(dev_id_info->proj_num));
645 		return -EINVAL;
646 	}
647 
648 	if (dev_id_info->major_ver < IQS5XX_MAJOR_VER_MIN) {
649 		dev_err(&client->dev, "Unsupported major version: %u\n",
650 			dev_id_info->major_ver);
651 		return iqs5xx_bl_open(client);
652 	}
653 
654 	switch (dev_id_info->bl_status) {
655 	case IQS5XX_BL_STATUS_AVAIL:
656 	case IQS5XX_BL_STATUS_NONE:
657 		break;
658 	default:
659 		dev_err(&client->dev,
660 			"Unrecognized bootloader status: 0x%02X\n",
661 			dev_id_info->bl_status);
662 		return -EINVAL;
663 	}
664 
665 	error = iqs5xx_axis_init(client);
666 	if (error)
667 		return error;
668 
669 	error = iqs5xx_read_byte(client, IQS5XX_SYS_CFG0, &val);
670 	if (error)
671 		return error;
672 
673 	val |= IQS5XX_SETUP_COMPLETE;
674 	val &= ~IQS5XX_SW_INPUT_EVENT;
675 	error = iqs5xx_write_byte(client, IQS5XX_SYS_CFG0, val);
676 	if (error)
677 		return error;
678 
679 	val = IQS5XX_TP_EVENT | IQS5XX_EVENT_MODE;
680 	error = iqs5xx_write_byte(client, IQS5XX_SYS_CFG1, val);
681 	if (error)
682 		return error;
683 
684 	error = iqs5xx_write_byte(client, IQS5XX_END_COMM, 0);
685 	if (error)
686 		return error;
687 
688 	iqs5xx->bl_status = dev_id_info->bl_status;
689 
690 	/*
691 	 * Closure of the first communication window that appears following the
692 	 * release of reset appears to kick off an initialization period during
693 	 * which further communication is met with clock stretching. The return
694 	 * from this function is delayed so that further communication attempts
695 	 * avoid this period.
696 	 */
697 	msleep(100);
698 
699 	return 0;
700 }
701 
702 static irqreturn_t iqs5xx_irq(int irq, void *data)
703 {
704 	struct iqs5xx_private *iqs5xx = data;
705 	struct iqs5xx_touch_data touch_data[IQS5XX_NUM_CONTACTS];
706 	struct i2c_client *client = iqs5xx->client;
707 	struct input_dev *input = iqs5xx->input;
708 	int error, i;
709 
710 	/*
711 	 * This check is purely a precaution, as the device does not assert the
712 	 * RDY output during bootloader mode. If the device operates outside of
713 	 * bootloader mode, the input device is guaranteed to be allocated.
714 	 */
715 	if (iqs5xx->bl_status == IQS5XX_BL_STATUS_RESET)
716 		return IRQ_NONE;
717 
718 	error = iqs5xx_read_burst(client, IQS5XX_ABS_X,
719 				  touch_data, sizeof(touch_data));
720 	if (error)
721 		return IRQ_NONE;
722 
723 	for (i = 0; i < ARRAY_SIZE(touch_data); i++) {
724 		u16 pressure = be16_to_cpu(touch_data[i].strength);
725 
726 		input_mt_slot(input, i);
727 		if (input_mt_report_slot_state(input, MT_TOOL_FINGER,
728 					       pressure != 0)) {
729 			input_report_abs(input, ABS_MT_POSITION_X,
730 					 be16_to_cpu(touch_data[i].abs_x));
731 			input_report_abs(input, ABS_MT_POSITION_Y,
732 					 be16_to_cpu(touch_data[i].abs_y));
733 			input_report_abs(input, ABS_MT_PRESSURE, pressure);
734 		}
735 	}
736 
737 	input_mt_sync_frame(input);
738 	input_sync(input);
739 
740 	error = iqs5xx_write_byte(client, IQS5XX_END_COMM, 0);
741 	if (error)
742 		return IRQ_NONE;
743 
744 	/*
745 	 * Once the communication window is closed, a small delay is added to
746 	 * ensure the device's RDY output has been deasserted by the time the
747 	 * interrupt handler returns.
748 	 */
749 	usleep_range(50, 100);
750 
751 	return IRQ_HANDLED;
752 }
753 
754 static int iqs5xx_fw_file_parse(struct i2c_client *client,
755 				const char *fw_file, u8 *pmap)
756 {
757 	const struct firmware *fw;
758 	struct iqs5xx_ihex_rec *rec;
759 	size_t pos = 0;
760 	int error, i;
761 	u16 rec_num = 1;
762 	u16 rec_addr;
763 	u8 rec_len, rec_type, rec_chksm, chksm;
764 	u8 rec_hdr[IQS5XX_REC_HDR_LEN];
765 	u8 rec_data[IQS5XX_REC_LEN_MAX];
766 
767 	/*
768 	 * Firmware exported from the vendor's configuration tool deviates from
769 	 * standard ihex as follows: (1) the checksum for records corresponding
770 	 * to user-exported settings is not recalculated, and (2) an address of
771 	 * 0xFFFF is used for the EOF record.
772 	 *
773 	 * Because the ihex2fw tool tolerates neither (1) nor (2), the slightly
774 	 * nonstandard ihex firmware is parsed directly by the driver.
775 	 */
776 	error = request_firmware(&fw, fw_file, &client->dev);
777 	if (error) {
778 		dev_err(&client->dev, "Failed to request firmware %s: %d\n",
779 			fw_file, error);
780 		return error;
781 	}
782 
783 	do {
784 		if (pos + sizeof(*rec) > fw->size) {
785 			dev_err(&client->dev, "Insufficient firmware size\n");
786 			error = -EINVAL;
787 			break;
788 		}
789 		rec = (struct iqs5xx_ihex_rec *)(fw->data + pos);
790 		pos += sizeof(*rec);
791 
792 		if (rec->start != ':') {
793 			dev_err(&client->dev, "Invalid start at record %u\n",
794 				rec_num);
795 			error = -EINVAL;
796 			break;
797 		}
798 
799 		error = hex2bin(rec_hdr, rec->len, sizeof(rec_hdr));
800 		if (error) {
801 			dev_err(&client->dev, "Invalid header at record %u\n",
802 				rec_num);
803 			break;
804 		}
805 
806 		rec_len = *rec_hdr;
807 		rec_addr = get_unaligned_be16(rec_hdr + sizeof(rec_len));
808 		rec_type = *(rec_hdr + sizeof(rec_len) + sizeof(rec_addr));
809 
810 		if (pos + rec_len * 2 > fw->size) {
811 			dev_err(&client->dev, "Insufficient firmware size\n");
812 			error = -EINVAL;
813 			break;
814 		}
815 		pos += (rec_len * 2);
816 
817 		error = hex2bin(rec_data, rec->data, rec_len);
818 		if (error) {
819 			dev_err(&client->dev, "Invalid data at record %u\n",
820 				rec_num);
821 			break;
822 		}
823 
824 		error = hex2bin(&rec_chksm,
825 				rec->data + rec_len * 2, sizeof(rec_chksm));
826 		if (error) {
827 			dev_err(&client->dev, "Invalid checksum at record %u\n",
828 				rec_num);
829 			break;
830 		}
831 
832 		chksm = 0;
833 		for (i = 0; i < sizeof(rec_hdr); i++)
834 			chksm += rec_hdr[i];
835 		for (i = 0; i < rec_len; i++)
836 			chksm += rec_data[i];
837 		chksm = ~chksm + 1;
838 
839 		if (chksm != rec_chksm && rec_addr < IQS5XX_CSTM) {
840 			dev_err(&client->dev,
841 				"Incorrect checksum at record %u\n",
842 				rec_num);
843 			error = -EINVAL;
844 			break;
845 		}
846 
847 		switch (rec_type) {
848 		case IQS5XX_REC_TYPE_DATA:
849 			if (rec_addr < IQS5XX_CHKSM ||
850 			    rec_addr > IQS5XX_PMAP_END) {
851 				dev_err(&client->dev,
852 					"Invalid address at record %u\n",
853 					rec_num);
854 				error = -EINVAL;
855 			} else {
856 				memcpy(pmap + rec_addr - IQS5XX_CHKSM,
857 				       rec_data, rec_len);
858 			}
859 			break;
860 		case IQS5XX_REC_TYPE_EOF:
861 			break;
862 		default:
863 			dev_err(&client->dev, "Invalid type at record %u\n",
864 				rec_num);
865 			error = -EINVAL;
866 		}
867 
868 		if (error)
869 			break;
870 
871 		rec_num++;
872 		while (pos < fw->size) {
873 			if (*(fw->data + pos) == ':')
874 				break;
875 			pos++;
876 		}
877 	} while (rec_type != IQS5XX_REC_TYPE_EOF);
878 
879 	release_firmware(fw);
880 
881 	return error;
882 }
883 
884 static int iqs5xx_fw_file_write(struct i2c_client *client, const char *fw_file)
885 {
886 	struct iqs5xx_private *iqs5xx = i2c_get_clientdata(client);
887 	int error;
888 	u8 *pmap;
889 
890 	if (iqs5xx->bl_status == IQS5XX_BL_STATUS_NONE)
891 		return -EPERM;
892 
893 	pmap = kzalloc(IQS5XX_PMAP_LEN, GFP_KERNEL);
894 	if (!pmap)
895 		return -ENOMEM;
896 
897 	error = iqs5xx_fw_file_parse(client, fw_file, pmap);
898 	if (error)
899 		goto err_kfree;
900 
901 	mutex_lock(&iqs5xx->lock);
902 
903 	/*
904 	 * Disable the interrupt line in case the first attempt(s) to enter the
905 	 * bootloader don't happen quickly enough, in which case the device may
906 	 * assert the RDY output until the next attempt.
907 	 */
908 	disable_irq(client->irq);
909 
910 	iqs5xx->bl_status = IQS5XX_BL_STATUS_RESET;
911 
912 	error = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_VER, 0);
913 	if (error) {
914 		error = iqs5xx_bl_open(client);
915 		if (error)
916 			goto err_reset;
917 	}
918 
919 	error = iqs5xx_bl_write(client, IQS5XX_CHKSM, pmap, IQS5XX_PMAP_LEN);
920 	if (error)
921 		goto err_reset;
922 
923 	error = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_CRC, 0);
924 	if (error)
925 		goto err_reset;
926 
927 	error = iqs5xx_bl_verify(client, IQS5XX_CSTM,
928 				 pmap + IQS5XX_CHKSM_LEN + IQS5XX_APP_LEN,
929 				 IQS5XX_CSTM_LEN);
930 	if (error)
931 		goto err_reset;
932 
933 	error = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_EXEC, 0);
934 
935 err_reset:
936 	if (error) {
937 		iqs5xx_reset(client);
938 		usleep_range(10000, 10100);
939 	}
940 
941 	error = iqs5xx_dev_init(client);
942 	if (!error && iqs5xx->bl_status == IQS5XX_BL_STATUS_RESET)
943 		error = -EINVAL;
944 
945 	enable_irq(client->irq);
946 
947 	mutex_unlock(&iqs5xx->lock);
948 
949 err_kfree:
950 	kfree(pmap);
951 
952 	return error;
953 }
954 
955 static ssize_t fw_file_store(struct device *dev, struct device_attribute *attr,
956 				const char *buf, size_t count)
957 {
958 	struct iqs5xx_private *iqs5xx = dev_get_drvdata(dev);
959 	struct i2c_client *client = iqs5xx->client;
960 	size_t len = count;
961 	bool input_reg = !iqs5xx->input;
962 	char fw_file[IQS5XX_FW_FILE_LEN + 1];
963 	int error;
964 
965 	if (!len)
966 		return -EINVAL;
967 
968 	if (buf[len - 1] == '\n')
969 		len--;
970 
971 	if (len > IQS5XX_FW_FILE_LEN)
972 		return -ENAMETOOLONG;
973 
974 	memcpy(fw_file, buf, len);
975 	fw_file[len] = '\0';
976 
977 	error = iqs5xx_fw_file_write(client, fw_file);
978 	if (error)
979 		return error;
980 
981 	/*
982 	 * If the input device was not allocated already, it is guaranteed to
983 	 * be allocated by this point and can finally be registered.
984 	 */
985 	if (input_reg) {
986 		error = input_register_device(iqs5xx->input);
987 		if (error) {
988 			dev_err(&client->dev,
989 				"Failed to register device: %d\n",
990 				error);
991 			return error;
992 		}
993 	}
994 
995 	return count;
996 }
997 
998 static DEVICE_ATTR_WO(fw_file);
999 
1000 static struct attribute *iqs5xx_attrs[] = {
1001 	&dev_attr_fw_file.attr,
1002 	NULL,
1003 };
1004 
1005 static const struct attribute_group iqs5xx_attr_group = {
1006 	.attrs = iqs5xx_attrs,
1007 };
1008 
1009 static int __maybe_unused iqs5xx_suspend(struct device *dev)
1010 {
1011 	struct iqs5xx_private *iqs5xx = dev_get_drvdata(dev);
1012 	struct input_dev *input = iqs5xx->input;
1013 	int error = 0;
1014 
1015 	if (!input)
1016 		return error;
1017 
1018 	mutex_lock(&input->mutex);
1019 
1020 	if (input_device_enabled(input))
1021 		error = iqs5xx_set_state(iqs5xx->client, IQS5XX_SUSPEND);
1022 
1023 	mutex_unlock(&input->mutex);
1024 
1025 	return error;
1026 }
1027 
1028 static int __maybe_unused iqs5xx_resume(struct device *dev)
1029 {
1030 	struct iqs5xx_private *iqs5xx = dev_get_drvdata(dev);
1031 	struct input_dev *input = iqs5xx->input;
1032 	int error = 0;
1033 
1034 	if (!input)
1035 		return error;
1036 
1037 	mutex_lock(&input->mutex);
1038 
1039 	if (input_device_enabled(input))
1040 		error = iqs5xx_set_state(iqs5xx->client, IQS5XX_RESUME);
1041 
1042 	mutex_unlock(&input->mutex);
1043 
1044 	return error;
1045 }
1046 
1047 static SIMPLE_DEV_PM_OPS(iqs5xx_pm, iqs5xx_suspend, iqs5xx_resume);
1048 
1049 static int iqs5xx_probe(struct i2c_client *client,
1050 			const struct i2c_device_id *id)
1051 {
1052 	struct iqs5xx_private *iqs5xx;
1053 	int error;
1054 
1055 	iqs5xx = devm_kzalloc(&client->dev, sizeof(*iqs5xx), GFP_KERNEL);
1056 	if (!iqs5xx)
1057 		return -ENOMEM;
1058 
1059 	i2c_set_clientdata(client, iqs5xx);
1060 	iqs5xx->client = client;
1061 
1062 	iqs5xx->reset_gpio = devm_gpiod_get(&client->dev,
1063 					    "reset", GPIOD_OUT_LOW);
1064 	if (IS_ERR(iqs5xx->reset_gpio)) {
1065 		error = PTR_ERR(iqs5xx->reset_gpio);
1066 		dev_err(&client->dev, "Failed to request GPIO: %d\n", error);
1067 		return error;
1068 	}
1069 
1070 	mutex_init(&iqs5xx->lock);
1071 
1072 	iqs5xx_reset(client);
1073 	usleep_range(10000, 10100);
1074 
1075 	error = iqs5xx_dev_init(client);
1076 	if (error)
1077 		return error;
1078 
1079 	error = devm_request_threaded_irq(&client->dev, client->irq,
1080 					  NULL, iqs5xx_irq, IRQF_ONESHOT,
1081 					  client->name, iqs5xx);
1082 	if (error) {
1083 		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
1084 		return error;
1085 	}
1086 
1087 	error = devm_device_add_group(&client->dev, &iqs5xx_attr_group);
1088 	if (error) {
1089 		dev_err(&client->dev, "Failed to add attributes: %d\n", error);
1090 		return error;
1091 	}
1092 
1093 	if (iqs5xx->input) {
1094 		error = input_register_device(iqs5xx->input);
1095 		if (error)
1096 			dev_err(&client->dev,
1097 				"Failed to register device: %d\n",
1098 				error);
1099 	}
1100 
1101 	return error;
1102 }
1103 
1104 static const struct i2c_device_id iqs5xx_id[] = {
1105 	{ "iqs550", 0 },
1106 	{ "iqs572", 1 },
1107 	{ "iqs525", 2 },
1108 	{ }
1109 };
1110 MODULE_DEVICE_TABLE(i2c, iqs5xx_id);
1111 
1112 static const struct of_device_id iqs5xx_of_match[] = {
1113 	{ .compatible = "azoteq,iqs550" },
1114 	{ .compatible = "azoteq,iqs572" },
1115 	{ .compatible = "azoteq,iqs525" },
1116 	{ }
1117 };
1118 MODULE_DEVICE_TABLE(of, iqs5xx_of_match);
1119 
1120 static struct i2c_driver iqs5xx_i2c_driver = {
1121 	.driver = {
1122 		.name		= "iqs5xx",
1123 		.of_match_table	= iqs5xx_of_match,
1124 		.pm		= &iqs5xx_pm,
1125 	},
1126 	.id_table	= iqs5xx_id,
1127 	.probe		= iqs5xx_probe,
1128 };
1129 module_i2c_driver(iqs5xx_i2c_driver);
1130 
1131 MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
1132 MODULE_DESCRIPTION("Azoteq IQS550/572/525 Trackpad/Touchscreen Controller");
1133 MODULE_LICENSE("GPL");
1134