xref: /openbmc/linux/drivers/hid/hid-cp2112.c (revision ae3473231e77a3f1909d48cd144cebe5e1d049b3)
1 /*
2  * hid-cp2112.c - Silicon Labs HID USB to SMBus master bridge
3  * Copyright (c) 2013,2014 Uplogix, Inc.
4  * David Barksdale <dbarksdale@uplogix.com>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  */
15 
16 /*
17  * The Silicon Labs CP2112 chip is a USB HID device which provides an
18  * SMBus controller for talking to slave devices and 8 GPIO pins. The
19  * host communicates with the CP2112 via raw HID reports.
20  *
21  * Data Sheet:
22  *   http://www.silabs.com/Support%20Documents/TechnicalDocs/CP2112.pdf
23  * Programming Interface Specification:
24  *   http://www.silabs.com/Support%20Documents/TechnicalDocs/AN495.pdf
25  */
26 
27 #include <linux/gpio.h>
28 #include <linux/gpio/driver.h>
29 #include <linux/hid.h>
30 #include <linux/i2c.h>
31 #include <linux/module.h>
32 #include <linux/nls.h>
33 #include <linux/usb/ch9.h>
34 #include "hid-ids.h"
35 
36 #define CP2112_REPORT_MAX_LENGTH		64
37 #define CP2112_GPIO_CONFIG_LENGTH		5
38 #define CP2112_GPIO_GET_LENGTH			2
39 #define CP2112_GPIO_SET_LENGTH			3
40 
41 enum {
42 	CP2112_GPIO_CONFIG		= 0x02,
43 	CP2112_GPIO_GET			= 0x03,
44 	CP2112_GPIO_SET			= 0x04,
45 	CP2112_GET_VERSION_INFO		= 0x05,
46 	CP2112_SMBUS_CONFIG		= 0x06,
47 	CP2112_DATA_READ_REQUEST	= 0x10,
48 	CP2112_DATA_WRITE_READ_REQUEST	= 0x11,
49 	CP2112_DATA_READ_FORCE_SEND	= 0x12,
50 	CP2112_DATA_READ_RESPONSE	= 0x13,
51 	CP2112_DATA_WRITE_REQUEST	= 0x14,
52 	CP2112_TRANSFER_STATUS_REQUEST	= 0x15,
53 	CP2112_TRANSFER_STATUS_RESPONSE	= 0x16,
54 	CP2112_CANCEL_TRANSFER		= 0x17,
55 	CP2112_LOCK_BYTE		= 0x20,
56 	CP2112_USB_CONFIG		= 0x21,
57 	CP2112_MANUFACTURER_STRING	= 0x22,
58 	CP2112_PRODUCT_STRING		= 0x23,
59 	CP2112_SERIAL_STRING		= 0x24,
60 };
61 
62 enum {
63 	STATUS0_IDLE		= 0x00,
64 	STATUS0_BUSY		= 0x01,
65 	STATUS0_COMPLETE	= 0x02,
66 	STATUS0_ERROR		= 0x03,
67 };
68 
69 enum {
70 	STATUS1_TIMEOUT_NACK		= 0x00,
71 	STATUS1_TIMEOUT_BUS		= 0x01,
72 	STATUS1_ARBITRATION_LOST	= 0x02,
73 	STATUS1_READ_INCOMPLETE		= 0x03,
74 	STATUS1_WRITE_INCOMPLETE	= 0x04,
75 	STATUS1_SUCCESS			= 0x05,
76 };
77 
78 struct cp2112_smbus_config_report {
79 	u8 report;		/* CP2112_SMBUS_CONFIG */
80 	__be32 clock_speed;	/* Hz */
81 	u8 device_address;	/* Stored in the upper 7 bits */
82 	u8 auto_send_read;	/* 1 = enabled, 0 = disabled */
83 	__be16 write_timeout;	/* ms, 0 = no timeout */
84 	__be16 read_timeout;	/* ms, 0 = no timeout */
85 	u8 scl_low_timeout;	/* 1 = enabled, 0 = disabled */
86 	__be16 retry_time;	/* # of retries, 0 = no limit */
87 } __packed;
88 
89 struct cp2112_usb_config_report {
90 	u8 report;	/* CP2112_USB_CONFIG */
91 	__le16 vid;	/* Vendor ID */
92 	__le16 pid;	/* Product ID */
93 	u8 max_power;	/* Power requested in 2mA units */
94 	u8 power_mode;	/* 0x00 = bus powered
95 			   0x01 = self powered & regulator off
96 			   0x02 = self powered & regulator on */
97 	u8 release_major;
98 	u8 release_minor;
99 	u8 mask;	/* What fields to program */
100 } __packed;
101 
102 struct cp2112_read_req_report {
103 	u8 report;	/* CP2112_DATA_READ_REQUEST */
104 	u8 slave_address;
105 	__be16 length;
106 } __packed;
107 
108 struct cp2112_write_read_req_report {
109 	u8 report;	/* CP2112_DATA_WRITE_READ_REQUEST */
110 	u8 slave_address;
111 	__be16 length;
112 	u8 target_address_length;
113 	u8 target_address[16];
114 } __packed;
115 
116 struct cp2112_write_req_report {
117 	u8 report;	/* CP2112_DATA_WRITE_REQUEST */
118 	u8 slave_address;
119 	u8 length;
120 	u8 data[61];
121 } __packed;
122 
123 struct cp2112_force_read_report {
124 	u8 report;	/* CP2112_DATA_READ_FORCE_SEND */
125 	__be16 length;
126 } __packed;
127 
128 struct cp2112_xfer_status_report {
129 	u8 report;	/* CP2112_TRANSFER_STATUS_RESPONSE */
130 	u8 status0;	/* STATUS0_* */
131 	u8 status1;	/* STATUS1_* */
132 	__be16 retries;
133 	__be16 length;
134 } __packed;
135 
136 struct cp2112_string_report {
137 	u8 dummy;		/* force .string to be aligned */
138 	u8 report;		/* CP2112_*_STRING */
139 	u8 length;		/* length in bytes of everyting after .report */
140 	u8 type;		/* USB_DT_STRING */
141 	wchar_t string[30];	/* UTF16_LITTLE_ENDIAN string */
142 } __packed;
143 
144 /* Number of times to request transfer status before giving up waiting for a
145    transfer to complete. This may need to be changed if SMBUS clock, retries,
146    or read/write/scl_low timeout settings are changed. */
147 static const int XFER_STATUS_RETRIES = 10;
148 
149 /* Time in ms to wait for a CP2112_DATA_READ_RESPONSE or
150    CP2112_TRANSFER_STATUS_RESPONSE. */
151 static const int RESPONSE_TIMEOUT = 50;
152 
153 static const struct hid_device_id cp2112_devices[] = {
154 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_CP2112) },
155 	{ }
156 };
157 MODULE_DEVICE_TABLE(hid, cp2112_devices);
158 
159 struct cp2112_device {
160 	struct i2c_adapter adap;
161 	struct hid_device *hdev;
162 	wait_queue_head_t wait;
163 	u8 read_data[61];
164 	u8 read_length;
165 	u8 hwversion;
166 	int xfer_status;
167 	atomic_t read_avail;
168 	atomic_t xfer_avail;
169 	struct gpio_chip gc;
170 	u8 *in_out_buffer;
171 	spinlock_t lock;
172 
173 	struct gpio_desc *desc[8];
174 	bool gpio_poll;
175 	struct delayed_work gpio_poll_worker;
176 	unsigned long irq_mask;
177 	u8 gpio_prev_state;
178 };
179 
180 static int gpio_push_pull = 0xFF;
181 module_param(gpio_push_pull, int, S_IRUGO | S_IWUSR);
182 MODULE_PARM_DESC(gpio_push_pull, "GPIO push-pull configuration bitmask");
183 
184 static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
185 {
186 	struct cp2112_device *dev = gpiochip_get_data(chip);
187 	struct hid_device *hdev = dev->hdev;
188 	u8 *buf = dev->in_out_buffer;
189 	unsigned long flags;
190 	int ret;
191 
192 	spin_lock_irqsave(&dev->lock, flags);
193 
194 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
195 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
196 				 HID_REQ_GET_REPORT);
197 	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
198 		hid_err(hdev, "error requesting GPIO config: %d\n", ret);
199 		goto exit;
200 	}
201 
202 	buf[1] &= ~(1 << offset);
203 	buf[2] = gpio_push_pull;
204 
205 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
206 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
207 				 HID_REQ_SET_REPORT);
208 	if (ret < 0) {
209 		hid_err(hdev, "error setting GPIO config: %d\n", ret);
210 		goto exit;
211 	}
212 
213 	ret = 0;
214 
215 exit:
216 	spin_unlock_irqrestore(&dev->lock, flags);
217 	return ret <= 0 ? ret : -EIO;
218 }
219 
220 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
221 {
222 	struct cp2112_device *dev = gpiochip_get_data(chip);
223 	struct hid_device *hdev = dev->hdev;
224 	u8 *buf = dev->in_out_buffer;
225 	unsigned long flags;
226 	int ret;
227 
228 	spin_lock_irqsave(&dev->lock, flags);
229 
230 	buf[0] = CP2112_GPIO_SET;
231 	buf[1] = value ? 0xff : 0;
232 	buf[2] = 1 << offset;
233 
234 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf,
235 				 CP2112_GPIO_SET_LENGTH, HID_FEATURE_REPORT,
236 				 HID_REQ_SET_REPORT);
237 	if (ret < 0)
238 		hid_err(hdev, "error setting GPIO values: %d\n", ret);
239 
240 	spin_unlock_irqrestore(&dev->lock, flags);
241 }
242 
243 static int cp2112_gpio_get_all(struct gpio_chip *chip)
244 {
245 	struct cp2112_device *dev = gpiochip_get_data(chip);
246 	struct hid_device *hdev = dev->hdev;
247 	u8 *buf = dev->in_out_buffer;
248 	unsigned long flags;
249 	int ret;
250 
251 	spin_lock_irqsave(&dev->lock, flags);
252 
253 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf,
254 				 CP2112_GPIO_GET_LENGTH, HID_FEATURE_REPORT,
255 				 HID_REQ_GET_REPORT);
256 	if (ret != CP2112_GPIO_GET_LENGTH) {
257 		hid_err(hdev, "error requesting GPIO values: %d\n", ret);
258 		ret = ret < 0 ? ret : -EIO;
259 		goto exit;
260 	}
261 
262 	ret = buf[1];
263 
264 exit:
265 	spin_unlock_irqrestore(&dev->lock, flags);
266 
267 	return ret;
268 }
269 
270 static int cp2112_gpio_get(struct gpio_chip *chip, unsigned int offset)
271 {
272 	int ret;
273 
274 	ret = cp2112_gpio_get_all(chip);
275 	if (ret < 0)
276 		return ret;
277 
278 	return (ret >> offset) & 1;
279 }
280 
281 static int cp2112_gpio_direction_output(struct gpio_chip *chip,
282 					unsigned offset, int value)
283 {
284 	struct cp2112_device *dev = gpiochip_get_data(chip);
285 	struct hid_device *hdev = dev->hdev;
286 	u8 *buf = dev->in_out_buffer;
287 	unsigned long flags;
288 	int ret;
289 
290 	spin_lock_irqsave(&dev->lock, flags);
291 
292 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
293 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
294 				 HID_REQ_GET_REPORT);
295 	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
296 		hid_err(hdev, "error requesting GPIO config: %d\n", ret);
297 		goto fail;
298 	}
299 
300 	buf[1] |= 1 << offset;
301 	buf[2] = gpio_push_pull;
302 
303 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
304 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
305 				 HID_REQ_SET_REPORT);
306 	if (ret < 0) {
307 		hid_err(hdev, "error setting GPIO config: %d\n", ret);
308 		goto fail;
309 	}
310 
311 	spin_unlock_irqrestore(&dev->lock, flags);
312 
313 	/*
314 	 * Set gpio value when output direction is already set,
315 	 * as specified in AN495, Rev. 0.2, cpt. 4.4
316 	 */
317 	cp2112_gpio_set(chip, offset, value);
318 
319 	return 0;
320 
321 fail:
322 	spin_unlock_irqrestore(&dev->lock, flags);
323 	return ret < 0 ? ret : -EIO;
324 }
325 
326 static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
327 			  u8 *data, size_t count, unsigned char report_type)
328 {
329 	u8 *buf;
330 	int ret;
331 
332 	buf = kmalloc(count, GFP_KERNEL);
333 	if (!buf)
334 		return -ENOMEM;
335 
336 	ret = hid_hw_raw_request(hdev, report_number, buf, count,
337 				       report_type, HID_REQ_GET_REPORT);
338 	memcpy(data, buf, count);
339 	kfree(buf);
340 	return ret;
341 }
342 
343 static int cp2112_hid_output(struct hid_device *hdev, u8 *data, size_t count,
344 			     unsigned char report_type)
345 {
346 	u8 *buf;
347 	int ret;
348 
349 	buf = kmemdup(data, count, GFP_KERNEL);
350 	if (!buf)
351 		return -ENOMEM;
352 
353 	if (report_type == HID_OUTPUT_REPORT)
354 		ret = hid_hw_output_report(hdev, buf, count);
355 	else
356 		ret = hid_hw_raw_request(hdev, buf[0], buf, count, report_type,
357 				HID_REQ_SET_REPORT);
358 
359 	kfree(buf);
360 	return ret;
361 }
362 
363 static int cp2112_wait(struct cp2112_device *dev, atomic_t *avail)
364 {
365 	int ret = 0;
366 
367 	/* We have sent either a CP2112_TRANSFER_STATUS_REQUEST or a
368 	 * CP2112_DATA_READ_FORCE_SEND and we are waiting for the response to
369 	 * come in cp2112_raw_event or timeout. There will only be one of these
370 	 * in flight at any one time. The timeout is extremely large and is a
371 	 * last resort if the CP2112 has died. If we do timeout we don't expect
372 	 * to receive the response which would cause data races, it's not like
373 	 * we can do anything about it anyway.
374 	 */
375 	ret = wait_event_interruptible_timeout(dev->wait,
376 		atomic_read(avail), msecs_to_jiffies(RESPONSE_TIMEOUT));
377 	if (-ERESTARTSYS == ret)
378 		return ret;
379 	if (!ret)
380 		return -ETIMEDOUT;
381 
382 	atomic_set(avail, 0);
383 	return 0;
384 }
385 
386 static int cp2112_xfer_status(struct cp2112_device *dev)
387 {
388 	struct hid_device *hdev = dev->hdev;
389 	u8 buf[2];
390 	int ret;
391 
392 	buf[0] = CP2112_TRANSFER_STATUS_REQUEST;
393 	buf[1] = 0x01;
394 	atomic_set(&dev->xfer_avail, 0);
395 
396 	ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
397 	if (ret < 0) {
398 		hid_warn(hdev, "Error requesting status: %d\n", ret);
399 		return ret;
400 	}
401 
402 	ret = cp2112_wait(dev, &dev->xfer_avail);
403 	if (ret)
404 		return ret;
405 
406 	return dev->xfer_status;
407 }
408 
409 static int cp2112_read(struct cp2112_device *dev, u8 *data, size_t size)
410 {
411 	struct hid_device *hdev = dev->hdev;
412 	struct cp2112_force_read_report report;
413 	int ret;
414 
415 	if (size > sizeof(dev->read_data))
416 		size = sizeof(dev->read_data);
417 	report.report = CP2112_DATA_READ_FORCE_SEND;
418 	report.length = cpu_to_be16(size);
419 
420 	atomic_set(&dev->read_avail, 0);
421 
422 	ret = cp2112_hid_output(hdev, &report.report, sizeof(report),
423 				HID_OUTPUT_REPORT);
424 	if (ret < 0) {
425 		hid_warn(hdev, "Error requesting data: %d\n", ret);
426 		return ret;
427 	}
428 
429 	ret = cp2112_wait(dev, &dev->read_avail);
430 	if (ret)
431 		return ret;
432 
433 	hid_dbg(hdev, "read %d of %zd bytes requested\n",
434 		dev->read_length, size);
435 
436 	if (size > dev->read_length)
437 		size = dev->read_length;
438 
439 	memcpy(data, dev->read_data, size);
440 	return dev->read_length;
441 }
442 
443 static int cp2112_read_req(void *buf, u8 slave_address, u16 length)
444 {
445 	struct cp2112_read_req_report *report = buf;
446 
447 	if (length < 1 || length > 512)
448 		return -EINVAL;
449 
450 	report->report = CP2112_DATA_READ_REQUEST;
451 	report->slave_address = slave_address << 1;
452 	report->length = cpu_to_be16(length);
453 	return sizeof(*report);
454 }
455 
456 static int cp2112_write_read_req(void *buf, u8 slave_address, u16 length,
457 				 u8 command, u8 *data, u8 data_length)
458 {
459 	struct cp2112_write_read_req_report *report = buf;
460 
461 	if (length < 1 || length > 512
462 	    || data_length > sizeof(report->target_address) - 1)
463 		return -EINVAL;
464 
465 	report->report = CP2112_DATA_WRITE_READ_REQUEST;
466 	report->slave_address = slave_address << 1;
467 	report->length = cpu_to_be16(length);
468 	report->target_address_length = data_length + 1;
469 	report->target_address[0] = command;
470 	memcpy(&report->target_address[1], data, data_length);
471 	return data_length + 6;
472 }
473 
474 static int cp2112_write_req(void *buf, u8 slave_address, u8 command, u8 *data,
475 			    u8 data_length)
476 {
477 	struct cp2112_write_req_report *report = buf;
478 
479 	if (data_length > sizeof(report->data) - 1)
480 		return -EINVAL;
481 
482 	report->report = CP2112_DATA_WRITE_REQUEST;
483 	report->slave_address = slave_address << 1;
484 	report->length = data_length + 1;
485 	report->data[0] = command;
486 	memcpy(&report->data[1], data, data_length);
487 	return data_length + 4;
488 }
489 
490 static int cp2112_i2c_write_req(void *buf, u8 slave_address, u8 *data,
491 				u8 data_length)
492 {
493 	struct cp2112_write_req_report *report = buf;
494 
495 	if (data_length > sizeof(report->data))
496 		return -EINVAL;
497 
498 	report->report = CP2112_DATA_WRITE_REQUEST;
499 	report->slave_address = slave_address << 1;
500 	report->length = data_length;
501 	memcpy(report->data, data, data_length);
502 	return data_length + 3;
503 }
504 
505 static int cp2112_i2c_write_read_req(void *buf, u8 slave_address,
506 				     u8 *addr, int addr_length,
507 				     int read_length)
508 {
509 	struct cp2112_write_read_req_report *report = buf;
510 
511 	if (read_length < 1 || read_length > 512 ||
512 	    addr_length > sizeof(report->target_address))
513 		return -EINVAL;
514 
515 	report->report = CP2112_DATA_WRITE_READ_REQUEST;
516 	report->slave_address = slave_address << 1;
517 	report->length = cpu_to_be16(read_length);
518 	report->target_address_length = addr_length;
519 	memcpy(report->target_address, addr, addr_length);
520 	return addr_length + 5;
521 }
522 
523 static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
524 			   int num)
525 {
526 	struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
527 	struct hid_device *hdev = dev->hdev;
528 	u8 buf[64];
529 	ssize_t count;
530 	ssize_t read_length = 0;
531 	u8 *read_buf = NULL;
532 	unsigned int retries;
533 	int ret;
534 
535 	hid_dbg(hdev, "I2C %d messages\n", num);
536 
537 	if (num == 1) {
538 		if (msgs->flags & I2C_M_RD) {
539 			hid_dbg(hdev, "I2C read %#04x len %d\n",
540 				msgs->addr, msgs->len);
541 			read_length = msgs->len;
542 			read_buf = msgs->buf;
543 			count = cp2112_read_req(buf, msgs->addr, msgs->len);
544 		} else {
545 			hid_dbg(hdev, "I2C write %#04x len %d\n",
546 				msgs->addr, msgs->len);
547 			count = cp2112_i2c_write_req(buf, msgs->addr,
548 						     msgs->buf, msgs->len);
549 		}
550 		if (count < 0)
551 			return count;
552 	} else if (dev->hwversion > 1 &&  /* no repeated start in rev 1 */
553 		   num == 2 &&
554 		   msgs[0].addr == msgs[1].addr &&
555 		   !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
556 		hid_dbg(hdev, "I2C write-read %#04x wlen %d rlen %d\n",
557 			msgs[0].addr, msgs[0].len, msgs[1].len);
558 		read_length = msgs[1].len;
559 		read_buf = msgs[1].buf;
560 		count = cp2112_i2c_write_read_req(buf, msgs[0].addr,
561 				msgs[0].buf, msgs[0].len, msgs[1].len);
562 		if (count < 0)
563 			return count;
564 	} else {
565 		hid_err(hdev,
566 			"Multi-message I2C transactions not supported\n");
567 		return -EOPNOTSUPP;
568 	}
569 
570 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
571 	if (ret < 0) {
572 		hid_err(hdev, "power management error: %d\n", ret);
573 		return ret;
574 	}
575 
576 	ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
577 	if (ret < 0) {
578 		hid_warn(hdev, "Error starting transaction: %d\n", ret);
579 		goto power_normal;
580 	}
581 
582 	for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
583 		ret = cp2112_xfer_status(dev);
584 		if (-EBUSY == ret)
585 			continue;
586 		if (ret < 0)
587 			goto power_normal;
588 		break;
589 	}
590 
591 	if (XFER_STATUS_RETRIES <= retries) {
592 		hid_warn(hdev, "Transfer timed out, cancelling.\n");
593 		buf[0] = CP2112_CANCEL_TRANSFER;
594 		buf[1] = 0x01;
595 
596 		ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
597 		if (ret < 0)
598 			hid_warn(hdev, "Error cancelling transaction: %d\n",
599 				 ret);
600 
601 		ret = -ETIMEDOUT;
602 		goto power_normal;
603 	}
604 
605 	for (count = 0; count < read_length;) {
606 		ret = cp2112_read(dev, read_buf + count, read_length - count);
607 		if (ret < 0)
608 			goto power_normal;
609 		if (ret == 0) {
610 			hid_err(hdev, "read returned 0\n");
611 			ret = -EIO;
612 			goto power_normal;
613 		}
614 		count += ret;
615 		if (count > read_length) {
616 			/*
617 			 * The hardware returned too much data.
618 			 * This is mostly harmless because cp2112_read()
619 			 * has a limit check so didn't overrun our
620 			 * buffer.  Nevertheless, we return an error
621 			 * because something is seriously wrong and
622 			 * it shouldn't go unnoticed.
623 			 */
624 			hid_err(hdev, "long read: %d > %zd\n",
625 				ret, read_length - count + ret);
626 			ret = -EIO;
627 			goto power_normal;
628 		}
629 	}
630 
631 	/* return the number of transferred messages */
632 	ret = num;
633 
634 power_normal:
635 	hid_hw_power(hdev, PM_HINT_NORMAL);
636 	hid_dbg(hdev, "I2C transfer finished: %d\n", ret);
637 	return ret;
638 }
639 
640 static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
641 		       unsigned short flags, char read_write, u8 command,
642 		       int size, union i2c_smbus_data *data)
643 {
644 	struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
645 	struct hid_device *hdev = dev->hdev;
646 	u8 buf[64];
647 	__le16 word;
648 	ssize_t count;
649 	size_t read_length = 0;
650 	unsigned int retries;
651 	int ret;
652 
653 	hid_dbg(hdev, "%s addr 0x%x flags 0x%x cmd 0x%x size %d\n",
654 		read_write == I2C_SMBUS_WRITE ? "write" : "read",
655 		addr, flags, command, size);
656 
657 	switch (size) {
658 	case I2C_SMBUS_BYTE:
659 		read_length = 1;
660 
661 		if (I2C_SMBUS_READ == read_write)
662 			count = cp2112_read_req(buf, addr, read_length);
663 		else
664 			count = cp2112_write_req(buf, addr, command, NULL,
665 						 0);
666 		break;
667 	case I2C_SMBUS_BYTE_DATA:
668 		read_length = 1;
669 
670 		if (I2C_SMBUS_READ == read_write)
671 			count = cp2112_write_read_req(buf, addr, read_length,
672 						      command, NULL, 0);
673 		else
674 			count = cp2112_write_req(buf, addr, command,
675 						 &data->byte, 1);
676 		break;
677 	case I2C_SMBUS_WORD_DATA:
678 		read_length = 2;
679 		word = cpu_to_le16(data->word);
680 
681 		if (I2C_SMBUS_READ == read_write)
682 			count = cp2112_write_read_req(buf, addr, read_length,
683 						      command, NULL, 0);
684 		else
685 			count = cp2112_write_req(buf, addr, command,
686 						 (u8 *)&word, 2);
687 		break;
688 	case I2C_SMBUS_PROC_CALL:
689 		size = I2C_SMBUS_WORD_DATA;
690 		read_write = I2C_SMBUS_READ;
691 		read_length = 2;
692 		word = cpu_to_le16(data->word);
693 
694 		count = cp2112_write_read_req(buf, addr, read_length, command,
695 					      (u8 *)&word, 2);
696 		break;
697 	case I2C_SMBUS_I2C_BLOCK_DATA:
698 		size = I2C_SMBUS_BLOCK_DATA;
699 		/* fallthrough */
700 	case I2C_SMBUS_BLOCK_DATA:
701 		if (I2C_SMBUS_READ == read_write) {
702 			count = cp2112_write_read_req(buf, addr,
703 						      I2C_SMBUS_BLOCK_MAX,
704 						      command, NULL, 0);
705 		} else {
706 			count = cp2112_write_req(buf, addr, command,
707 						 data->block,
708 						 data->block[0] + 1);
709 		}
710 		break;
711 	case I2C_SMBUS_BLOCK_PROC_CALL:
712 		size = I2C_SMBUS_BLOCK_DATA;
713 		read_write = I2C_SMBUS_READ;
714 
715 		count = cp2112_write_read_req(buf, addr, I2C_SMBUS_BLOCK_MAX,
716 					      command, data->block,
717 					      data->block[0] + 1);
718 		break;
719 	default:
720 		hid_warn(hdev, "Unsupported transaction %d\n", size);
721 		return -EOPNOTSUPP;
722 	}
723 
724 	if (count < 0)
725 		return count;
726 
727 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
728 	if (ret < 0) {
729 		hid_err(hdev, "power management error: %d\n", ret);
730 		return ret;
731 	}
732 
733 	ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
734 	if (ret < 0) {
735 		hid_warn(hdev, "Error starting transaction: %d\n", ret);
736 		goto power_normal;
737 	}
738 
739 	for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
740 		ret = cp2112_xfer_status(dev);
741 		if (-EBUSY == ret)
742 			continue;
743 		if (ret < 0)
744 			goto power_normal;
745 		break;
746 	}
747 
748 	if (XFER_STATUS_RETRIES <= retries) {
749 		hid_warn(hdev, "Transfer timed out, cancelling.\n");
750 		buf[0] = CP2112_CANCEL_TRANSFER;
751 		buf[1] = 0x01;
752 
753 		ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
754 		if (ret < 0)
755 			hid_warn(hdev, "Error cancelling transaction: %d\n",
756 				 ret);
757 
758 		ret = -ETIMEDOUT;
759 		goto power_normal;
760 	}
761 
762 	if (I2C_SMBUS_WRITE == read_write) {
763 		ret = 0;
764 		goto power_normal;
765 	}
766 
767 	if (I2C_SMBUS_BLOCK_DATA == size)
768 		read_length = ret;
769 
770 	ret = cp2112_read(dev, buf, read_length);
771 	if (ret < 0)
772 		goto power_normal;
773 	if (ret != read_length) {
774 		hid_warn(hdev, "short read: %d < %zd\n", ret, read_length);
775 		ret = -EIO;
776 		goto power_normal;
777 	}
778 
779 	switch (size) {
780 	case I2C_SMBUS_BYTE:
781 	case I2C_SMBUS_BYTE_DATA:
782 		data->byte = buf[0];
783 		break;
784 	case I2C_SMBUS_WORD_DATA:
785 		data->word = le16_to_cpup((__le16 *)buf);
786 		break;
787 	case I2C_SMBUS_BLOCK_DATA:
788 		if (read_length > I2C_SMBUS_BLOCK_MAX) {
789 			ret = -EPROTO;
790 			goto power_normal;
791 		}
792 
793 		memcpy(data->block, buf, read_length);
794 		break;
795 	}
796 
797 	ret = 0;
798 power_normal:
799 	hid_hw_power(hdev, PM_HINT_NORMAL);
800 	hid_dbg(hdev, "transfer finished: %d\n", ret);
801 	return ret;
802 }
803 
804 static u32 cp2112_functionality(struct i2c_adapter *adap)
805 {
806 	return I2C_FUNC_I2C |
807 		I2C_FUNC_SMBUS_BYTE |
808 		I2C_FUNC_SMBUS_BYTE_DATA |
809 		I2C_FUNC_SMBUS_WORD_DATA |
810 		I2C_FUNC_SMBUS_BLOCK_DATA |
811 		I2C_FUNC_SMBUS_I2C_BLOCK |
812 		I2C_FUNC_SMBUS_PROC_CALL |
813 		I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
814 }
815 
816 static const struct i2c_algorithm smbus_algorithm = {
817 	.master_xfer	= cp2112_i2c_xfer,
818 	.smbus_xfer	= cp2112_xfer,
819 	.functionality	= cp2112_functionality,
820 };
821 
822 static int cp2112_get_usb_config(struct hid_device *hdev,
823 				 struct cp2112_usb_config_report *cfg)
824 {
825 	int ret;
826 
827 	ret = cp2112_hid_get(hdev, CP2112_USB_CONFIG, (u8 *)cfg, sizeof(*cfg),
828 			     HID_FEATURE_REPORT);
829 	if (ret != sizeof(*cfg)) {
830 		hid_err(hdev, "error reading usb config: %d\n", ret);
831 		if (ret < 0)
832 			return ret;
833 		return -EIO;
834 	}
835 
836 	return 0;
837 }
838 
839 static int cp2112_set_usb_config(struct hid_device *hdev,
840 				 struct cp2112_usb_config_report *cfg)
841 {
842 	int ret;
843 
844 	BUG_ON(cfg->report != CP2112_USB_CONFIG);
845 
846 	ret = cp2112_hid_output(hdev, (u8 *)cfg, sizeof(*cfg),
847 				HID_FEATURE_REPORT);
848 	if (ret != sizeof(*cfg)) {
849 		hid_err(hdev, "error writing usb config: %d\n", ret);
850 		if (ret < 0)
851 			return ret;
852 		return -EIO;
853 	}
854 
855 	return 0;
856 }
857 
858 static void chmod_sysfs_attrs(struct hid_device *hdev);
859 
860 #define CP2112_CONFIG_ATTR(name, store, format, ...) \
861 static ssize_t name##_store(struct device *kdev, \
862 			    struct device_attribute *attr, const char *buf, \
863 			    size_t count) \
864 { \
865 	struct hid_device *hdev = to_hid_device(kdev); \
866 	struct cp2112_usb_config_report cfg; \
867 	int ret = cp2112_get_usb_config(hdev, &cfg); \
868 	if (ret) \
869 		return ret; \
870 	store; \
871 	ret = cp2112_set_usb_config(hdev, &cfg); \
872 	if (ret) \
873 		return ret; \
874 	chmod_sysfs_attrs(hdev); \
875 	return count; \
876 } \
877 static ssize_t name##_show(struct device *kdev, \
878 			   struct device_attribute *attr, char *buf) \
879 { \
880 	struct hid_device *hdev = to_hid_device(kdev); \
881 	struct cp2112_usb_config_report cfg; \
882 	int ret = cp2112_get_usb_config(hdev, &cfg); \
883 	if (ret) \
884 		return ret; \
885 	return scnprintf(buf, PAGE_SIZE, format, ##__VA_ARGS__); \
886 } \
887 static DEVICE_ATTR_RW(name);
888 
889 CP2112_CONFIG_ATTR(vendor_id, ({
890 	u16 vid;
891 
892 	if (sscanf(buf, "%hi", &vid) != 1)
893 		return -EINVAL;
894 
895 	cfg.vid = cpu_to_le16(vid);
896 	cfg.mask = 0x01;
897 }), "0x%04x\n", le16_to_cpu(cfg.vid));
898 
899 CP2112_CONFIG_ATTR(product_id, ({
900 	u16 pid;
901 
902 	if (sscanf(buf, "%hi", &pid) != 1)
903 		return -EINVAL;
904 
905 	cfg.pid = cpu_to_le16(pid);
906 	cfg.mask = 0x02;
907 }), "0x%04x\n", le16_to_cpu(cfg.pid));
908 
909 CP2112_CONFIG_ATTR(max_power, ({
910 	int mA;
911 
912 	if (sscanf(buf, "%i", &mA) != 1)
913 		return -EINVAL;
914 
915 	cfg.max_power = (mA + 1) / 2;
916 	cfg.mask = 0x04;
917 }), "%u mA\n", cfg.max_power * 2);
918 
919 CP2112_CONFIG_ATTR(power_mode, ({
920 	if (sscanf(buf, "%hhi", &cfg.power_mode) != 1)
921 		return -EINVAL;
922 
923 	cfg.mask = 0x08;
924 }), "%u\n", cfg.power_mode);
925 
926 CP2112_CONFIG_ATTR(release_version, ({
927 	if (sscanf(buf, "%hhi.%hhi", &cfg.release_major, &cfg.release_minor)
928 	    != 2)
929 		return -EINVAL;
930 
931 	cfg.mask = 0x10;
932 }), "%u.%u\n", cfg.release_major, cfg.release_minor);
933 
934 #undef CP2112_CONFIG_ATTR
935 
936 struct cp2112_pstring_attribute {
937 	struct device_attribute attr;
938 	unsigned char report;
939 };
940 
941 static ssize_t pstr_store(struct device *kdev,
942 			  struct device_attribute *kattr, const char *buf,
943 			  size_t count)
944 {
945 	struct hid_device *hdev = to_hid_device(kdev);
946 	struct cp2112_pstring_attribute *attr =
947 		container_of(kattr, struct cp2112_pstring_attribute, attr);
948 	struct cp2112_string_report report;
949 	int ret;
950 
951 	memset(&report, 0, sizeof(report));
952 
953 	ret = utf8s_to_utf16s(buf, count, UTF16_LITTLE_ENDIAN,
954 			      report.string, ARRAY_SIZE(report.string));
955 	report.report = attr->report;
956 	report.length = ret * sizeof(report.string[0]) + 2;
957 	report.type = USB_DT_STRING;
958 
959 	ret = cp2112_hid_output(hdev, &report.report, report.length + 1,
960 				HID_FEATURE_REPORT);
961 	if (ret != report.length + 1) {
962 		hid_err(hdev, "error writing %s string: %d\n", kattr->attr.name,
963 			ret);
964 		if (ret < 0)
965 			return ret;
966 		return -EIO;
967 	}
968 
969 	chmod_sysfs_attrs(hdev);
970 	return count;
971 }
972 
973 static ssize_t pstr_show(struct device *kdev,
974 			 struct device_attribute *kattr, char *buf)
975 {
976 	struct hid_device *hdev = to_hid_device(kdev);
977 	struct cp2112_pstring_attribute *attr =
978 		container_of(kattr, struct cp2112_pstring_attribute, attr);
979 	struct cp2112_string_report report;
980 	u8 length;
981 	int ret;
982 
983 	ret = cp2112_hid_get(hdev, attr->report, &report.report,
984 			     sizeof(report) - 1, HID_FEATURE_REPORT);
985 	if (ret < 3) {
986 		hid_err(hdev, "error reading %s string: %d\n", kattr->attr.name,
987 			ret);
988 		if (ret < 0)
989 			return ret;
990 		return -EIO;
991 	}
992 
993 	if (report.length < 2) {
994 		hid_err(hdev, "invalid %s string length: %d\n",
995 			kattr->attr.name, report.length);
996 		return -EIO;
997 	}
998 
999 	length = report.length > ret - 1 ? ret - 1 : report.length;
1000 	length = (length - 2) / sizeof(report.string[0]);
1001 	ret = utf16s_to_utf8s(report.string, length, UTF16_LITTLE_ENDIAN, buf,
1002 			      PAGE_SIZE - 1);
1003 	buf[ret++] = '\n';
1004 	return ret;
1005 }
1006 
1007 #define CP2112_PSTR_ATTR(name, _report) \
1008 static struct cp2112_pstring_attribute dev_attr_##name = { \
1009 	.attr = __ATTR(name, (S_IWUSR | S_IRUGO), pstr_show, pstr_store), \
1010 	.report = _report, \
1011 };
1012 
1013 CP2112_PSTR_ATTR(manufacturer,	CP2112_MANUFACTURER_STRING);
1014 CP2112_PSTR_ATTR(product,	CP2112_PRODUCT_STRING);
1015 CP2112_PSTR_ATTR(serial,	CP2112_SERIAL_STRING);
1016 
1017 #undef CP2112_PSTR_ATTR
1018 
1019 static const struct attribute_group cp2112_attr_group = {
1020 	.attrs = (struct attribute *[]){
1021 		&dev_attr_vendor_id.attr,
1022 		&dev_attr_product_id.attr,
1023 		&dev_attr_max_power.attr,
1024 		&dev_attr_power_mode.attr,
1025 		&dev_attr_release_version.attr,
1026 		&dev_attr_manufacturer.attr.attr,
1027 		&dev_attr_product.attr.attr,
1028 		&dev_attr_serial.attr.attr,
1029 		NULL
1030 	}
1031 };
1032 
1033 /* Chmoding our sysfs attributes is simply a way to expose which fields in the
1034  * PROM have already been programmed. We do not depend on this preventing
1035  * writing to these attributes since the CP2112 will simply ignore writes to
1036  * already-programmed fields. This is why there is no sense in fixing this
1037  * racy behaviour.
1038  */
1039 static void chmod_sysfs_attrs(struct hid_device *hdev)
1040 {
1041 	struct attribute **attr;
1042 	u8 buf[2];
1043 	int ret;
1044 
1045 	ret = cp2112_hid_get(hdev, CP2112_LOCK_BYTE, buf, sizeof(buf),
1046 			     HID_FEATURE_REPORT);
1047 	if (ret != sizeof(buf)) {
1048 		hid_err(hdev, "error reading lock byte: %d\n", ret);
1049 		return;
1050 	}
1051 
1052 	for (attr = cp2112_attr_group.attrs; *attr; ++attr) {
1053 		umode_t mode = (buf[1] & 1) ? S_IWUSR | S_IRUGO : S_IRUGO;
1054 		ret = sysfs_chmod_file(&hdev->dev.kobj, *attr, mode);
1055 		if (ret < 0)
1056 			hid_err(hdev, "error chmoding sysfs file %s\n",
1057 				(*attr)->name);
1058 		buf[1] >>= 1;
1059 	}
1060 }
1061 
1062 static void cp2112_gpio_irq_ack(struct irq_data *d)
1063 {
1064 }
1065 
1066 static void cp2112_gpio_irq_mask(struct irq_data *d)
1067 {
1068 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
1069 	struct cp2112_device *dev = gpiochip_get_data(gc);
1070 
1071 	__clear_bit(d->hwirq, &dev->irq_mask);
1072 }
1073 
1074 static void cp2112_gpio_irq_unmask(struct irq_data *d)
1075 {
1076 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
1077 	struct cp2112_device *dev = gpiochip_get_data(gc);
1078 
1079 	__set_bit(d->hwirq, &dev->irq_mask);
1080 }
1081 
1082 static void cp2112_gpio_poll_callback(struct work_struct *work)
1083 {
1084 	struct cp2112_device *dev = container_of(work, struct cp2112_device,
1085 						 gpio_poll_worker.work);
1086 	struct irq_data *d;
1087 	u8 gpio_mask;
1088 	u8 virqs = (u8)dev->irq_mask;
1089 	u32 irq_type;
1090 	int irq, virq, ret;
1091 
1092 	ret = cp2112_gpio_get_all(&dev->gc);
1093 	if (ret == -ENODEV) /* the hardware has been disconnected */
1094 		return;
1095 	if (ret < 0)
1096 		goto exit;
1097 
1098 	gpio_mask = ret;
1099 
1100 	while (virqs) {
1101 		virq = ffs(virqs) - 1;
1102 		virqs &= ~BIT(virq);
1103 
1104 		if (!dev->gc.to_irq)
1105 			break;
1106 
1107 		irq = dev->gc.to_irq(&dev->gc, virq);
1108 
1109 		d = irq_get_irq_data(irq);
1110 		if (!d)
1111 			continue;
1112 
1113 		irq_type = irqd_get_trigger_type(d);
1114 
1115 		if (gpio_mask & BIT(virq)) {
1116 			/* Level High */
1117 
1118 			if (irq_type & IRQ_TYPE_LEVEL_HIGH)
1119 				handle_nested_irq(irq);
1120 
1121 			if ((irq_type & IRQ_TYPE_EDGE_RISING) &&
1122 			    !(dev->gpio_prev_state & BIT(virq)))
1123 				handle_nested_irq(irq);
1124 		} else {
1125 			/* Level Low */
1126 
1127 			if (irq_type & IRQ_TYPE_LEVEL_LOW)
1128 				handle_nested_irq(irq);
1129 
1130 			if ((irq_type & IRQ_TYPE_EDGE_FALLING) &&
1131 			    (dev->gpio_prev_state & BIT(virq)))
1132 				handle_nested_irq(irq);
1133 		}
1134 	}
1135 
1136 	dev->gpio_prev_state = gpio_mask;
1137 
1138 exit:
1139 	if (dev->gpio_poll)
1140 		schedule_delayed_work(&dev->gpio_poll_worker, 10);
1141 }
1142 
1143 
1144 static unsigned int cp2112_gpio_irq_startup(struct irq_data *d)
1145 {
1146 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
1147 	struct cp2112_device *dev = gpiochip_get_data(gc);
1148 
1149 	INIT_DELAYED_WORK(&dev->gpio_poll_worker, cp2112_gpio_poll_callback);
1150 
1151 	cp2112_gpio_direction_input(gc, d->hwirq);
1152 
1153 	if (!dev->gpio_poll) {
1154 		dev->gpio_poll = true;
1155 		schedule_delayed_work(&dev->gpio_poll_worker, 0);
1156 	}
1157 
1158 	cp2112_gpio_irq_unmask(d);
1159 	return 0;
1160 }
1161 
1162 static void cp2112_gpio_irq_shutdown(struct irq_data *d)
1163 {
1164 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
1165 	struct cp2112_device *dev = gpiochip_get_data(gc);
1166 
1167 	cancel_delayed_work_sync(&dev->gpio_poll_worker);
1168 }
1169 
1170 static int cp2112_gpio_irq_type(struct irq_data *d, unsigned int type)
1171 {
1172 	return 0;
1173 }
1174 
1175 static struct irq_chip cp2112_gpio_irqchip = {
1176 	.name = "cp2112-gpio",
1177 	.irq_startup = cp2112_gpio_irq_startup,
1178 	.irq_shutdown = cp2112_gpio_irq_shutdown,
1179 	.irq_ack = cp2112_gpio_irq_ack,
1180 	.irq_mask = cp2112_gpio_irq_mask,
1181 	.irq_unmask = cp2112_gpio_irq_unmask,
1182 	.irq_set_type = cp2112_gpio_irq_type,
1183 };
1184 
1185 static int __maybe_unused cp2112_allocate_irq(struct cp2112_device *dev,
1186 					      int pin)
1187 {
1188 	int ret;
1189 
1190 	if (dev->desc[pin])
1191 		return -EINVAL;
1192 
1193 	dev->desc[pin] = gpiochip_request_own_desc(&dev->gc, pin,
1194 						   "HID/I2C:Event");
1195 	if (IS_ERR(dev->desc[pin])) {
1196 		dev_err(dev->gc.parent, "Failed to request GPIO\n");
1197 		return PTR_ERR(dev->desc[pin]);
1198 	}
1199 
1200 	ret = gpiochip_lock_as_irq(&dev->gc, pin);
1201 	if (ret) {
1202 		dev_err(dev->gc.parent, "Failed to lock GPIO as interrupt\n");
1203 		goto err_desc;
1204 	}
1205 
1206 	ret = gpiod_to_irq(dev->desc[pin]);
1207 	if (ret < 0) {
1208 		dev_err(dev->gc.parent, "Failed to translate GPIO to IRQ\n");
1209 		goto err_lock;
1210 	}
1211 
1212 	return ret;
1213 
1214 err_lock:
1215 	gpiochip_unlock_as_irq(&dev->gc, pin);
1216 err_desc:
1217 	gpiochip_free_own_desc(dev->desc[pin]);
1218 	dev->desc[pin] = NULL;
1219 	return ret;
1220 }
1221 
1222 static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
1223 {
1224 	struct cp2112_device *dev;
1225 	u8 buf[3];
1226 	struct cp2112_smbus_config_report config;
1227 	int ret;
1228 
1229 	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
1230 	if (!dev)
1231 		return -ENOMEM;
1232 
1233 	dev->in_out_buffer = devm_kzalloc(&hdev->dev, CP2112_REPORT_MAX_LENGTH,
1234 					  GFP_KERNEL);
1235 	if (!dev->in_out_buffer)
1236 		return -ENOMEM;
1237 
1238 	spin_lock_init(&dev->lock);
1239 
1240 	ret = hid_parse(hdev);
1241 	if (ret) {
1242 		hid_err(hdev, "parse failed\n");
1243 		return ret;
1244 	}
1245 
1246 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
1247 	if (ret) {
1248 		hid_err(hdev, "hw start failed\n");
1249 		return ret;
1250 	}
1251 
1252 	ret = hid_hw_open(hdev);
1253 	if (ret) {
1254 		hid_err(hdev, "hw open failed\n");
1255 		goto err_hid_stop;
1256 	}
1257 
1258 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
1259 	if (ret < 0) {
1260 		hid_err(hdev, "power management error: %d\n", ret);
1261 		goto err_hid_close;
1262 	}
1263 
1264 	ret = cp2112_hid_get(hdev, CP2112_GET_VERSION_INFO, buf, sizeof(buf),
1265 			     HID_FEATURE_REPORT);
1266 	if (ret != sizeof(buf)) {
1267 		hid_err(hdev, "error requesting version\n");
1268 		if (ret >= 0)
1269 			ret = -EIO;
1270 		goto err_power_normal;
1271 	}
1272 
1273 	hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
1274 		 buf[1], buf[2]);
1275 
1276 	ret = cp2112_hid_get(hdev, CP2112_SMBUS_CONFIG, (u8 *)&config,
1277 			     sizeof(config), HID_FEATURE_REPORT);
1278 	if (ret != sizeof(config)) {
1279 		hid_err(hdev, "error requesting SMBus config\n");
1280 		if (ret >= 0)
1281 			ret = -EIO;
1282 		goto err_power_normal;
1283 	}
1284 
1285 	config.retry_time = cpu_to_be16(1);
1286 
1287 	ret = cp2112_hid_output(hdev, (u8 *)&config, sizeof(config),
1288 				HID_FEATURE_REPORT);
1289 	if (ret != sizeof(config)) {
1290 		hid_err(hdev, "error setting SMBus config\n");
1291 		if (ret >= 0)
1292 			ret = -EIO;
1293 		goto err_power_normal;
1294 	}
1295 
1296 	hid_set_drvdata(hdev, (void *)dev);
1297 	dev->hdev		= hdev;
1298 	dev->adap.owner		= THIS_MODULE;
1299 	dev->adap.class		= I2C_CLASS_HWMON;
1300 	dev->adap.algo		= &smbus_algorithm;
1301 	dev->adap.algo_data	= dev;
1302 	dev->adap.dev.parent	= &hdev->dev;
1303 	snprintf(dev->adap.name, sizeof(dev->adap.name),
1304 		 "CP2112 SMBus Bridge on hiddev%d", hdev->minor);
1305 	dev->hwversion = buf[2];
1306 	init_waitqueue_head(&dev->wait);
1307 
1308 	hid_device_io_start(hdev);
1309 	ret = i2c_add_adapter(&dev->adap);
1310 	hid_device_io_stop(hdev);
1311 
1312 	if (ret) {
1313 		hid_err(hdev, "error registering i2c adapter\n");
1314 		goto err_power_normal;
1315 	}
1316 
1317 	hid_dbg(hdev, "adapter registered\n");
1318 
1319 	dev->gc.label			= "cp2112_gpio";
1320 	dev->gc.direction_input		= cp2112_gpio_direction_input;
1321 	dev->gc.direction_output	= cp2112_gpio_direction_output;
1322 	dev->gc.set			= cp2112_gpio_set;
1323 	dev->gc.get			= cp2112_gpio_get;
1324 	dev->gc.base			= -1;
1325 	dev->gc.ngpio			= 8;
1326 	dev->gc.can_sleep		= 1;
1327 	dev->gc.parent			= &hdev->dev;
1328 
1329 	ret = gpiochip_add_data(&dev->gc, dev);
1330 	if (ret < 0) {
1331 		hid_err(hdev, "error registering gpio chip\n");
1332 		goto err_free_i2c;
1333 	}
1334 
1335 	ret = sysfs_create_group(&hdev->dev.kobj, &cp2112_attr_group);
1336 	if (ret < 0) {
1337 		hid_err(hdev, "error creating sysfs attrs\n");
1338 		goto err_gpiochip_remove;
1339 	}
1340 
1341 	chmod_sysfs_attrs(hdev);
1342 	hid_hw_power(hdev, PM_HINT_NORMAL);
1343 
1344 	ret = gpiochip_irqchip_add(&dev->gc, &cp2112_gpio_irqchip, 0,
1345 				   handle_simple_irq, IRQ_TYPE_NONE);
1346 	if (ret) {
1347 		dev_err(dev->gc.parent, "failed to add IRQ chip\n");
1348 		goto err_sysfs_remove;
1349 	}
1350 
1351 	return ret;
1352 
1353 err_sysfs_remove:
1354 	sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
1355 err_gpiochip_remove:
1356 	gpiochip_remove(&dev->gc);
1357 err_free_i2c:
1358 	i2c_del_adapter(&dev->adap);
1359 err_power_normal:
1360 	hid_hw_power(hdev, PM_HINT_NORMAL);
1361 err_hid_close:
1362 	hid_hw_close(hdev);
1363 err_hid_stop:
1364 	hid_hw_stop(hdev);
1365 	return ret;
1366 }
1367 
1368 static void cp2112_remove(struct hid_device *hdev)
1369 {
1370 	struct cp2112_device *dev = hid_get_drvdata(hdev);
1371 	int i;
1372 
1373 	sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
1374 	i2c_del_adapter(&dev->adap);
1375 
1376 	if (dev->gpio_poll) {
1377 		dev->gpio_poll = false;
1378 		cancel_delayed_work_sync(&dev->gpio_poll_worker);
1379 	}
1380 
1381 	for (i = 0; i < ARRAY_SIZE(dev->desc); i++) {
1382 		gpiochip_unlock_as_irq(&dev->gc, i);
1383 		gpiochip_free_own_desc(dev->desc[i]);
1384 	}
1385 
1386 	gpiochip_remove(&dev->gc);
1387 	/* i2c_del_adapter has finished removing all i2c devices from our
1388 	 * adapter. Well behaved devices should no longer call our cp2112_xfer
1389 	 * and should have waited for any pending calls to finish. It has also
1390 	 * waited for device_unregister(&adap->dev) to complete. Therefore we
1391 	 * can safely free our struct cp2112_device.
1392 	 */
1393 	hid_hw_close(hdev);
1394 	hid_hw_stop(hdev);
1395 }
1396 
1397 static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
1398 			    u8 *data, int size)
1399 {
1400 	struct cp2112_device *dev = hid_get_drvdata(hdev);
1401 	struct cp2112_xfer_status_report *xfer = (void *)data;
1402 
1403 	switch (data[0]) {
1404 	case CP2112_TRANSFER_STATUS_RESPONSE:
1405 		hid_dbg(hdev, "xfer status: %02x %02x %04x %04x\n",
1406 			xfer->status0, xfer->status1,
1407 			be16_to_cpu(xfer->retries), be16_to_cpu(xfer->length));
1408 
1409 		switch (xfer->status0) {
1410 		case STATUS0_IDLE:
1411 			dev->xfer_status = -EAGAIN;
1412 			break;
1413 		case STATUS0_BUSY:
1414 			dev->xfer_status = -EBUSY;
1415 			break;
1416 		case STATUS0_COMPLETE:
1417 			dev->xfer_status = be16_to_cpu(xfer->length);
1418 			break;
1419 		case STATUS0_ERROR:
1420 			switch (xfer->status1) {
1421 			case STATUS1_TIMEOUT_NACK:
1422 			case STATUS1_TIMEOUT_BUS:
1423 				dev->xfer_status = -ETIMEDOUT;
1424 				break;
1425 			default:
1426 				dev->xfer_status = -EIO;
1427 				break;
1428 			}
1429 			break;
1430 		default:
1431 			dev->xfer_status = -EINVAL;
1432 			break;
1433 		}
1434 
1435 		atomic_set(&dev->xfer_avail, 1);
1436 		break;
1437 	case CP2112_DATA_READ_RESPONSE:
1438 		hid_dbg(hdev, "read response: %02x %02x\n", data[1], data[2]);
1439 
1440 		dev->read_length = data[2];
1441 		if (dev->read_length > sizeof(dev->read_data))
1442 			dev->read_length = sizeof(dev->read_data);
1443 
1444 		memcpy(dev->read_data, &data[3], dev->read_length);
1445 		atomic_set(&dev->read_avail, 1);
1446 		break;
1447 	default:
1448 		hid_err(hdev, "unknown report\n");
1449 
1450 		return 0;
1451 	}
1452 
1453 	wake_up_interruptible(&dev->wait);
1454 	return 1;
1455 }
1456 
1457 static struct hid_driver cp2112_driver = {
1458 	.name		= "cp2112",
1459 	.id_table	= cp2112_devices,
1460 	.probe		= cp2112_probe,
1461 	.remove		= cp2112_remove,
1462 	.raw_event	= cp2112_raw_event,
1463 };
1464 
1465 module_hid_driver(cp2112_driver);
1466 MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
1467 MODULE_AUTHOR("David Barksdale <dbarksdale@uplogix.com>");
1468 MODULE_LICENSE("GPL");
1469 
1470