xref: /openbmc/linux/drivers/hid/hid-mcp2221.c (revision b58c6630)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * MCP2221A - Microchip USB to I2C Host Protocol Bridge
4  *
5  * Copyright (c) 2020, Rishi Gupta <gupt21@gmail.com>
6  *
7  * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/20005565B.pdf
8  */
9 
10 #include <linux/module.h>
11 #include <linux/err.h>
12 #include <linux/mutex.h>
13 #include <linux/completion.h>
14 #include <linux/delay.h>
15 #include <linux/hid.h>
16 #include <linux/hidraw.h>
17 #include <linux/i2c.h>
18 #include "hid-ids.h"
19 
20 /* Commands codes in a raw output report */
21 enum {
22 	MCP2221_I2C_WR_DATA = 0x90,
23 	MCP2221_I2C_WR_NO_STOP = 0x94,
24 	MCP2221_I2C_RD_DATA = 0x91,
25 	MCP2221_I2C_RD_RPT_START = 0x93,
26 	MCP2221_I2C_GET_DATA = 0x40,
27 	MCP2221_I2C_PARAM_OR_STATUS	= 0x10,
28 	MCP2221_I2C_SET_SPEED = 0x20,
29 	MCP2221_I2C_CANCEL = 0x10,
30 };
31 
32 /* Response codes in a raw input report */
33 enum {
34 	MCP2221_SUCCESS = 0x00,
35 	MCP2221_I2C_ENG_BUSY = 0x01,
36 	MCP2221_I2C_START_TOUT = 0x12,
37 	MCP2221_I2C_STOP_TOUT = 0x62,
38 	MCP2221_I2C_WRADDRL_TOUT = 0x23,
39 	MCP2221_I2C_WRDATA_TOUT = 0x44,
40 	MCP2221_I2C_WRADDRL_NACK = 0x25,
41 	MCP2221_I2C_MASK_ADDR_NACK = 0x40,
42 	MCP2221_I2C_WRADDRL_SEND = 0x21,
43 	MCP2221_I2C_ADDR_NACK = 0x25,
44 	MCP2221_I2C_READ_COMPL = 0x55,
45 };
46 
47 /*
48  * There is no way to distinguish responses. Therefore next command
49  * is sent only after response to previous has been received. Mutex
50  * lock is used for this purpose mainly.
51  */
52 struct mcp2221 {
53 	struct hid_device *hdev;
54 	struct i2c_adapter adapter;
55 	struct mutex lock;
56 	struct completion wait_in_report;
57 	u8 *rxbuf;
58 	u8 txbuf[64];
59 	int rxbuf_idx;
60 	int status;
61 	u8 cur_i2c_clk_div;
62 };
63 
64 /*
65  * Default i2c bus clock frequency 400 kHz. Modify this if you
66  * want to set some other frequency (min 50 kHz - max 400 kHz).
67  */
68 static uint i2c_clk_freq = 400;
69 
70 /* Synchronously send output report to the device */
71 static int mcp_send_report(struct mcp2221 *mcp,
72 					u8 *out_report, size_t len)
73 {
74 	u8 *buf;
75 	int ret;
76 
77 	buf = kmemdup(out_report, len, GFP_KERNEL);
78 	if (!buf)
79 		return -ENOMEM;
80 
81 	/* mcp2221 uses interrupt endpoint for out reports */
82 	ret = hid_hw_output_report(mcp->hdev, buf, len);
83 	kfree(buf);
84 
85 	if (ret < 0)
86 		return ret;
87 	return 0;
88 }
89 
90 /*
91  * Send o/p report to the device and wait for i/p report to be
92  * received from the device. If the device does not respond,
93  * we timeout.
94  */
95 static int mcp_send_data_req_status(struct mcp2221 *mcp,
96 			u8 *out_report, int len)
97 {
98 	int ret;
99 	unsigned long t;
100 
101 	reinit_completion(&mcp->wait_in_report);
102 
103 	ret = mcp_send_report(mcp, out_report, len);
104 	if (ret)
105 		return ret;
106 
107 	t = wait_for_completion_timeout(&mcp->wait_in_report,
108 							msecs_to_jiffies(4000));
109 	if (!t)
110 		return -ETIMEDOUT;
111 
112 	return mcp->status;
113 }
114 
115 /* Check pass/fail for actual communication with i2c slave */
116 static int mcp_chk_last_cmd_status(struct mcp2221 *mcp)
117 {
118 	memset(mcp->txbuf, 0, 8);
119 	mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
120 
121 	return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
122 }
123 
124 /* Cancels last command releasing i2c bus just in case occupied */
125 static int mcp_cancel_last_cmd(struct mcp2221 *mcp)
126 {
127 	memset(mcp->txbuf, 0, 8);
128 	mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
129 	mcp->txbuf[2] = MCP2221_I2C_CANCEL;
130 
131 	return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
132 }
133 
134 static int mcp_set_i2c_speed(struct mcp2221 *mcp)
135 {
136 	int ret;
137 
138 	memset(mcp->txbuf, 0, 8);
139 	mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
140 	mcp->txbuf[3] = MCP2221_I2C_SET_SPEED;
141 	mcp->txbuf[4] = mcp->cur_i2c_clk_div;
142 
143 	ret = mcp_send_data_req_status(mcp, mcp->txbuf, 8);
144 	if (ret) {
145 		/* Small delay is needed here */
146 		usleep_range(980, 1000);
147 		mcp_cancel_last_cmd(mcp);
148 	}
149 
150 	return 0;
151 }
152 
153 /*
154  * An output report can contain minimum 1 and maximum 60 user data
155  * bytes. If the number of data bytes is more then 60, we send it
156  * in chunks of 60 bytes. Last chunk may contain exactly 60 or less
157  * bytes. Total number of bytes is informed in very first report to
158  * mcp2221, from that point onwards it first collect all the data
159  * from host and then send to i2c slave device.
160  */
161 static int mcp_i2c_write(struct mcp2221 *mcp,
162 				struct i2c_msg *msg, int type, u8 last_status)
163 {
164 	int ret, len, idx, sent;
165 
166 	idx = 0;
167 	sent  = 0;
168 	if (msg->len < 60)
169 		len = msg->len;
170 	else
171 		len = 60;
172 
173 	do {
174 		mcp->txbuf[0] = type;
175 		mcp->txbuf[1] = msg->len & 0xff;
176 		mcp->txbuf[2] = msg->len >> 8;
177 		mcp->txbuf[3] = (u8)(msg->addr << 1);
178 
179 		memcpy(&mcp->txbuf[4], &msg->buf[idx], len);
180 
181 		ret = mcp_send_data_req_status(mcp, mcp->txbuf, len + 4);
182 		if (ret)
183 			return ret;
184 
185 		usleep_range(980, 1000);
186 
187 		if (last_status) {
188 			ret = mcp_chk_last_cmd_status(mcp);
189 			if (ret)
190 				return ret;
191 		}
192 
193 		sent = sent + len;
194 		if (sent >= msg->len)
195 			break;
196 
197 		idx = idx + len;
198 		if ((msg->len - sent) < 60)
199 			len = msg->len - sent;
200 		else
201 			len = 60;
202 
203 		/*
204 		 * Testing shows delay is needed between successive writes
205 		 * otherwise next write fails on first-try from i2c core.
206 		 * This value is obtained through automated stress testing.
207 		 */
208 		usleep_range(980, 1000);
209 	} while (len > 0);
210 
211 	return ret;
212 }
213 
214 /*
215  * Device reads all data (0 - 65535 bytes) from i2c slave device and
216  * stores it in device itself. This data is read back from device to
217  * host in multiples of 60 bytes using input reports.
218  */
219 static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
220 				struct i2c_msg *msg, int type, u16 smbus_addr,
221 				u8 smbus_len, u8 *smbus_buf)
222 {
223 	int ret;
224 	u16 total_len;
225 
226 	mcp->txbuf[0] = type;
227 	if (msg) {
228 		mcp->txbuf[1] = msg->len & 0xff;
229 		mcp->txbuf[2] = msg->len >> 8;
230 		mcp->txbuf[3] = (u8)(msg->addr << 1);
231 		total_len = msg->len;
232 		mcp->rxbuf = msg->buf;
233 	} else {
234 		mcp->txbuf[1] = smbus_len;
235 		mcp->txbuf[2] = 0;
236 		mcp->txbuf[3] = (u8)(smbus_addr << 1);
237 		total_len = smbus_len;
238 		mcp->rxbuf = smbus_buf;
239 	}
240 
241 	ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4);
242 	if (ret)
243 		return ret;
244 
245 	mcp->rxbuf_idx = 0;
246 
247 	do {
248 		memset(mcp->txbuf, 0, 4);
249 		mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
250 
251 		ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
252 		if (ret)
253 			return ret;
254 
255 		ret = mcp_chk_last_cmd_status(mcp);
256 		if (ret)
257 			return ret;
258 
259 		usleep_range(980, 1000);
260 	} while (mcp->rxbuf_idx < total_len);
261 
262 	return ret;
263 }
264 
265 static int mcp_i2c_xfer(struct i2c_adapter *adapter,
266 				struct i2c_msg msgs[], int num)
267 {
268 	int ret;
269 	struct mcp2221 *mcp = i2c_get_adapdata(adapter);
270 
271 	hid_hw_power(mcp->hdev, PM_HINT_FULLON);
272 
273 	mutex_lock(&mcp->lock);
274 
275 	/* Setting speed before every transaction is required for mcp2221 */
276 	ret = mcp_set_i2c_speed(mcp);
277 	if (ret)
278 		goto exit;
279 
280 	if (num == 1) {
281 		if (msgs->flags & I2C_M_RD) {
282 			ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA,
283 							0, 0, NULL);
284 		} else {
285 			ret = mcp_i2c_write(mcp, msgs, MCP2221_I2C_WR_DATA, 1);
286 		}
287 		if (ret)
288 			goto exit;
289 		ret = num;
290 	} else if (num == 2) {
291 		/* Ex transaction; send reg address and read its contents */
292 		if (msgs[0].addr == msgs[1].addr &&
293 			!(msgs[0].flags & I2C_M_RD) &&
294 			 (msgs[1].flags & I2C_M_RD)) {
295 
296 			ret = mcp_i2c_write(mcp, &msgs[0],
297 						MCP2221_I2C_WR_NO_STOP, 0);
298 			if (ret)
299 				goto exit;
300 
301 			ret = mcp_i2c_smbus_read(mcp, &msgs[1],
302 						MCP2221_I2C_RD_RPT_START,
303 						0, 0, NULL);
304 			if (ret)
305 				goto exit;
306 			ret = num;
307 		} else {
308 			dev_err(&adapter->dev,
309 				"unsupported multi-msg i2c transaction\n");
310 			ret = -EOPNOTSUPP;
311 		}
312 	} else {
313 		dev_err(&adapter->dev,
314 			"unsupported multi-msg i2c transaction\n");
315 		ret = -EOPNOTSUPP;
316 	}
317 
318 exit:
319 	hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
320 	mutex_unlock(&mcp->lock);
321 	return ret;
322 }
323 
324 static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
325 				u8 command, u8 *buf, u8 len, int type,
326 				u8 last_status)
327 {
328 	int data_len, ret;
329 
330 	mcp->txbuf[0] = type;
331 	mcp->txbuf[1] = len + 1; /* 1 is due to command byte itself */
332 	mcp->txbuf[2] = 0;
333 	mcp->txbuf[3] = (u8)(addr << 1);
334 	mcp->txbuf[4] = command;
335 
336 	switch (len) {
337 	case 0:
338 		data_len = 5;
339 		break;
340 	case 1:
341 		mcp->txbuf[5] = buf[0];
342 		data_len = 6;
343 		break;
344 	case 2:
345 		mcp->txbuf[5] = buf[0];
346 		mcp->txbuf[6] = buf[1];
347 		data_len = 7;
348 		break;
349 	default:
350 		memcpy(&mcp->txbuf[5], buf, len);
351 		data_len = len + 5;
352 	}
353 
354 	ret = mcp_send_data_req_status(mcp, mcp->txbuf, data_len);
355 	if (ret)
356 		return ret;
357 
358 	if (last_status) {
359 		usleep_range(980, 1000);
360 
361 		ret = mcp_chk_last_cmd_status(mcp);
362 		if (ret)
363 			return ret;
364 	}
365 
366 	return ret;
367 }
368 
369 static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
370 				unsigned short flags, char read_write,
371 				u8 command, int size,
372 				union i2c_smbus_data *data)
373 {
374 	int ret;
375 	struct mcp2221 *mcp = i2c_get_adapdata(adapter);
376 
377 	hid_hw_power(mcp->hdev, PM_HINT_FULLON);
378 
379 	mutex_lock(&mcp->lock);
380 
381 	ret = mcp_set_i2c_speed(mcp);
382 	if (ret)
383 		goto exit;
384 
385 	switch (size) {
386 
387 	case I2C_SMBUS_QUICK:
388 		if (read_write == I2C_SMBUS_READ)
389 			ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
390 						addr, 0, &data->byte);
391 		else
392 			ret = mcp_smbus_write(mcp, addr, command, NULL,
393 						0, MCP2221_I2C_WR_DATA, 1);
394 		break;
395 	case I2C_SMBUS_BYTE:
396 		if (read_write == I2C_SMBUS_READ)
397 			ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
398 						addr, 1, &data->byte);
399 		else
400 			ret = mcp_smbus_write(mcp, addr, command, NULL,
401 						0, MCP2221_I2C_WR_DATA, 1);
402 		break;
403 	case I2C_SMBUS_BYTE_DATA:
404 		if (read_write == I2C_SMBUS_READ) {
405 			ret = mcp_smbus_write(mcp, addr, command, NULL,
406 						0, MCP2221_I2C_WR_NO_STOP, 0);
407 			if (ret)
408 				goto exit;
409 
410 			ret = mcp_i2c_smbus_read(mcp, NULL,
411 						MCP2221_I2C_RD_RPT_START,
412 						addr, 1, &data->byte);
413 		} else {
414 			ret = mcp_smbus_write(mcp, addr, command, &data->byte,
415 						1, MCP2221_I2C_WR_DATA, 1);
416 		}
417 		break;
418 	case I2C_SMBUS_WORD_DATA:
419 		if (read_write == I2C_SMBUS_READ) {
420 			ret = mcp_smbus_write(mcp, addr, command, NULL,
421 						0, MCP2221_I2C_WR_NO_STOP, 0);
422 			if (ret)
423 				goto exit;
424 
425 			ret = mcp_i2c_smbus_read(mcp, NULL,
426 						MCP2221_I2C_RD_RPT_START,
427 						addr, 2, (u8 *)&data->word);
428 		} else {
429 			ret = mcp_smbus_write(mcp, addr, command,
430 						(u8 *)&data->word, 2,
431 						MCP2221_I2C_WR_DATA, 1);
432 		}
433 		break;
434 	case I2C_SMBUS_BLOCK_DATA:
435 		if (read_write == I2C_SMBUS_READ) {
436 			ret = mcp_smbus_write(mcp, addr, command, NULL,
437 						0, MCP2221_I2C_WR_NO_STOP, 1);
438 			if (ret)
439 				goto exit;
440 
441 			mcp->rxbuf_idx = 0;
442 			mcp->rxbuf = data->block;
443 			mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
444 			ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
445 			if (ret)
446 				goto exit;
447 		} else {
448 			if (!data->block[0]) {
449 				ret = -EINVAL;
450 				goto exit;
451 			}
452 			ret = mcp_smbus_write(mcp, addr, command, data->block,
453 						data->block[0] + 1,
454 						MCP2221_I2C_WR_DATA, 1);
455 		}
456 		break;
457 	case I2C_SMBUS_I2C_BLOCK_DATA:
458 		if (read_write == I2C_SMBUS_READ) {
459 			ret = mcp_smbus_write(mcp, addr, command, NULL,
460 						0, MCP2221_I2C_WR_NO_STOP, 1);
461 			if (ret)
462 				goto exit;
463 
464 			mcp->rxbuf_idx = 0;
465 			mcp->rxbuf = data->block;
466 			mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
467 			ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
468 			if (ret)
469 				goto exit;
470 		} else {
471 			if (!data->block[0]) {
472 				ret = -EINVAL;
473 				goto exit;
474 			}
475 			ret = mcp_smbus_write(mcp, addr, command,
476 						&data->block[1], data->block[0],
477 						MCP2221_I2C_WR_DATA, 1);
478 		}
479 		break;
480 	case I2C_SMBUS_PROC_CALL:
481 		ret = mcp_smbus_write(mcp, addr, command,
482 						(u8 *)&data->word,
483 						2, MCP2221_I2C_WR_NO_STOP, 0);
484 		if (ret)
485 			goto exit;
486 
487 		ret = mcp_i2c_smbus_read(mcp, NULL,
488 						MCP2221_I2C_RD_RPT_START,
489 						addr, 2, (u8 *)&data->word);
490 		break;
491 	case I2C_SMBUS_BLOCK_PROC_CALL:
492 		ret = mcp_smbus_write(mcp, addr, command, data->block,
493 						data->block[0] + 1,
494 						MCP2221_I2C_WR_NO_STOP, 0);
495 		if (ret)
496 			goto exit;
497 
498 		ret = mcp_i2c_smbus_read(mcp, NULL,
499 						MCP2221_I2C_RD_RPT_START,
500 						addr, I2C_SMBUS_BLOCK_MAX,
501 						data->block);
502 		break;
503 	default:
504 		dev_err(&mcp->adapter.dev,
505 			"unsupported smbus transaction size:%d\n", size);
506 		ret = -EOPNOTSUPP;
507 	}
508 
509 exit:
510 	hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
511 	mutex_unlock(&mcp->lock);
512 	return ret;
513 }
514 
515 static u32 mcp_i2c_func(struct i2c_adapter *adapter)
516 {
517 	return I2C_FUNC_I2C |
518 			I2C_FUNC_SMBUS_READ_BLOCK_DATA |
519 			I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
520 			(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_PEC);
521 }
522 
523 static const struct i2c_algorithm mcp_i2c_algo = {
524 	.master_xfer = mcp_i2c_xfer,
525 	.smbus_xfer = mcp_smbus_xfer,
526 	.functionality = mcp_i2c_func,
527 };
528 
529 /* Gives current state of i2c engine inside mcp2221 */
530 static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
531 				u8 *data, u8 idx)
532 {
533 	int ret;
534 
535 	switch (data[idx]) {
536 	case MCP2221_I2C_WRADDRL_NACK:
537 	case MCP2221_I2C_WRADDRL_SEND:
538 		ret = -ENXIO;
539 		break;
540 	case MCP2221_I2C_START_TOUT:
541 	case MCP2221_I2C_STOP_TOUT:
542 	case MCP2221_I2C_WRADDRL_TOUT:
543 	case MCP2221_I2C_WRDATA_TOUT:
544 		ret = -ETIMEDOUT;
545 		break;
546 	case MCP2221_I2C_ENG_BUSY:
547 		ret = -EAGAIN;
548 		break;
549 	case MCP2221_SUCCESS:
550 		ret = 0x00;
551 		break;
552 	default:
553 		ret = -EIO;
554 	}
555 
556 	return ret;
557 }
558 
559 /*
560  * MCP2221 uses interrupt endpoint for input reports. This function
561  * is called by HID layer when it receives i/p report from mcp2221,
562  * which is actually a response to the previously sent command.
563  *
564  * MCP2221A firmware specific return codes are parsed and 0 or
565  * appropriate negative error code is returned. Delayed response
566  * results in timeout error and stray reponses results in -EIO.
567  */
568 static int mcp2221_raw_event(struct hid_device *hdev,
569 				struct hid_report *report, u8 *data, int size)
570 {
571 	u8 *buf;
572 	struct mcp2221 *mcp = hid_get_drvdata(hdev);
573 
574 	switch (data[0]) {
575 
576 	case MCP2221_I2C_WR_DATA:
577 	case MCP2221_I2C_WR_NO_STOP:
578 	case MCP2221_I2C_RD_DATA:
579 	case MCP2221_I2C_RD_RPT_START:
580 		switch (data[1]) {
581 		case MCP2221_SUCCESS:
582 			mcp->status = 0;
583 			break;
584 		default:
585 			mcp->status = mcp_get_i2c_eng_state(mcp, data, 2);
586 		}
587 		complete(&mcp->wait_in_report);
588 		break;
589 
590 	case MCP2221_I2C_PARAM_OR_STATUS:
591 		switch (data[1]) {
592 		case MCP2221_SUCCESS:
593 			if ((mcp->txbuf[3] == MCP2221_I2C_SET_SPEED) &&
594 				(data[3] != MCP2221_I2C_SET_SPEED)) {
595 				mcp->status = -EAGAIN;
596 				break;
597 			}
598 			if (data[20] & MCP2221_I2C_MASK_ADDR_NACK) {
599 				mcp->status = -ENXIO;
600 				break;
601 			}
602 			mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
603 			break;
604 		default:
605 			mcp->status = -EIO;
606 		}
607 		complete(&mcp->wait_in_report);
608 		break;
609 
610 	case MCP2221_I2C_GET_DATA:
611 		switch (data[1]) {
612 		case MCP2221_SUCCESS:
613 			if (data[2] == MCP2221_I2C_ADDR_NACK) {
614 				mcp->status = -ENXIO;
615 				break;
616 			}
617 			if (!mcp_get_i2c_eng_state(mcp, data, 2)
618 				&& (data[3] == 0)) {
619 				mcp->status = 0;
620 				break;
621 			}
622 			if (data[3] == 127) {
623 				mcp->status = -EIO;
624 				break;
625 			}
626 			if (data[2] == MCP2221_I2C_READ_COMPL) {
627 				buf = mcp->rxbuf;
628 				memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
629 				mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
630 				mcp->status = 0;
631 				break;
632 			}
633 			mcp->status = -EIO;
634 			break;
635 		default:
636 			mcp->status = -EIO;
637 		}
638 		complete(&mcp->wait_in_report);
639 		break;
640 
641 	default:
642 		mcp->status = -EIO;
643 		complete(&mcp->wait_in_report);
644 	}
645 
646 	return 1;
647 }
648 
649 static int mcp2221_probe(struct hid_device *hdev,
650 					const struct hid_device_id *id)
651 {
652 	int ret;
653 	struct mcp2221 *mcp;
654 
655 	mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
656 	if (!mcp)
657 		return -ENOMEM;
658 
659 	ret = hid_parse(hdev);
660 	if (ret) {
661 		hid_err(hdev, "can't parse reports\n");
662 		return ret;
663 	}
664 
665 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
666 	if (ret) {
667 		hid_err(hdev, "can't start hardware\n");
668 		return ret;
669 	}
670 
671 	ret = hid_hw_open(hdev);
672 	if (ret) {
673 		hid_err(hdev, "can't open device\n");
674 		goto err_hstop;
675 	}
676 
677 	mutex_init(&mcp->lock);
678 	init_completion(&mcp->wait_in_report);
679 	hid_set_drvdata(hdev, mcp);
680 	mcp->hdev = hdev;
681 
682 	/* Set I2C bus clock diviser */
683 	if (i2c_clk_freq > 400)
684 		i2c_clk_freq = 400;
685 	if (i2c_clk_freq < 50)
686 		i2c_clk_freq = 50;
687 	mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
688 
689 	mcp->adapter.owner = THIS_MODULE;
690 	mcp->adapter.class = I2C_CLASS_HWMON;
691 	mcp->adapter.algo = &mcp_i2c_algo;
692 	mcp->adapter.retries = 1;
693 	mcp->adapter.dev.parent = &hdev->dev;
694 	snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
695 			"MCP2221 usb-i2c bridge on hidraw%d",
696 			((struct hidraw *)hdev->hidraw)->minor);
697 
698 	ret = i2c_add_adapter(&mcp->adapter);
699 	if (ret) {
700 		hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
701 		goto err_i2c;
702 	}
703 	i2c_set_adapdata(&mcp->adapter, mcp);
704 
705 	return 0;
706 
707 err_i2c:
708 	hid_hw_close(mcp->hdev);
709 err_hstop:
710 	hid_hw_stop(mcp->hdev);
711 	return ret;
712 }
713 
714 static void mcp2221_remove(struct hid_device *hdev)
715 {
716 	struct mcp2221 *mcp = hid_get_drvdata(hdev);
717 
718 	i2c_del_adapter(&mcp->adapter);
719 	hid_hw_close(mcp->hdev);
720 	hid_hw_stop(mcp->hdev);
721 }
722 
723 static const struct hid_device_id mcp2221_devices[] = {
724 	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
725 	{ }
726 };
727 MODULE_DEVICE_TABLE(hid, mcp2221_devices);
728 
729 static struct hid_driver mcp2221_driver = {
730 	.name		= "mcp2221",
731 	.id_table	= mcp2221_devices,
732 	.probe		= mcp2221_probe,
733 	.remove		= mcp2221_remove,
734 	.raw_event	= mcp2221_raw_event,
735 };
736 
737 /* Register with HID core */
738 module_hid_driver(mcp2221_driver);
739 
740 MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
741 MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
742 MODULE_LICENSE("GPL v2");
743