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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: https://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/bitfield.h>
14#include <linux/completion.h>
15#include <linux/delay.h>
16#include <linux/hid.h>
17#include <linux/hidraw.h>
18#include <linux/i2c.h>
19#include <linux/gpio/driver.h>
20#include <linux/iio/iio.h>
21#include "hid-ids.h"
22
23/* Commands codes in a raw output report */
24enum {
25 MCP2221_I2C_WR_DATA = 0x90,
26 MCP2221_I2C_WR_NO_STOP = 0x94,
27 MCP2221_I2C_RD_DATA = 0x91,
28 MCP2221_I2C_RD_RPT_START = 0x93,
29 MCP2221_I2C_GET_DATA = 0x40,
30 MCP2221_I2C_PARAM_OR_STATUS = 0x10,
31 MCP2221_I2C_SET_SPEED = 0x20,
32 MCP2221_I2C_CANCEL = 0x10,
33 MCP2221_GPIO_SET = 0x50,
34 MCP2221_GPIO_GET = 0x51,
35 MCP2221_SET_SRAM_SETTINGS = 0x60,
36 MCP2221_GET_SRAM_SETTINGS = 0x61,
37 MCP2221_READ_FLASH_DATA = 0xb0,
38};
39
40/* Response codes in a raw input report */
41enum {
42 MCP2221_SUCCESS = 0x00,
43 MCP2221_I2C_ENG_BUSY = 0x01,
44 MCP2221_I2C_START_TOUT = 0x12,
45 MCP2221_I2C_STOP_TOUT = 0x62,
46 MCP2221_I2C_WRADDRL_TOUT = 0x23,
47 MCP2221_I2C_WRDATA_TOUT = 0x44,
48 MCP2221_I2C_WRADDRL_NACK = 0x25,
49 MCP2221_I2C_MASK_ADDR_NACK = 0x40,
50 MCP2221_I2C_WRADDRL_SEND = 0x21,
51 MCP2221_I2C_ADDR_NACK = 0x25,
52 MCP2221_I2C_READ_PARTIAL = 0x54,
53 MCP2221_I2C_READ_COMPL = 0x55,
54 MCP2221_ALT_F_NOT_GPIOV = 0xEE,
55 MCP2221_ALT_F_NOT_GPIOD = 0xEF,
56};
57
58/* MCP GPIO direction encoding */
59enum {
60 MCP2221_DIR_OUT = 0x00,
61 MCP2221_DIR_IN = 0x01,
62};
63
64#define MCP_NGPIO 4
65
66/* MCP GPIO set command layout */
67struct mcp_set_gpio {
68 u8 cmd;
69 u8 dummy;
70 struct {
71 u8 change_value;
72 u8 value;
73 u8 change_direction;
74 u8 direction;
75 } gpio[MCP_NGPIO];
76} __packed;
77
78/* MCP GPIO get command layout */
79struct mcp_get_gpio {
80 u8 cmd;
81 u8 dummy;
82 struct {
83 u8 value;
84 u8 direction;
85 } gpio[MCP_NGPIO];
86} __packed;
87
88/*
89 * There is no way to distinguish responses. Therefore next command
90 * is sent only after response to previous has been received. Mutex
91 * lock is used for this purpose mainly.
92 */
93struct mcp2221 {
94 struct hid_device *hdev;
95 struct i2c_adapter adapter;
96 struct mutex lock;
97 struct completion wait_in_report;
98 struct delayed_work init_work;
99 u8 *rxbuf;
100 u8 txbuf[64];
101 int rxbuf_idx;
102 int status;
103 u8 cur_i2c_clk_div;
104 struct gpio_chip *gc;
105 u8 gp_idx;
106 u8 gpio_dir;
107 u8 mode[4];
108#if IS_REACHABLE(CONFIG_IIO)
109 struct iio_chan_spec iio_channels[3];
110 u16 adc_values[3];
111 u8 adc_scale;
112 u8 dac_value;
113 u16 dac_scale;
114#endif
115};
116
117struct mcp2221_iio {
118 struct mcp2221 *mcp;
119};
120
121/*
122 * Default i2c bus clock frequency 400 kHz. Modify this if you
123 * want to set some other frequency (min 50 kHz - max 400 kHz).
124 */
125static uint i2c_clk_freq = 400;
126
127/* Synchronously send output report to the device */
128static int mcp_send_report(struct mcp2221 *mcp,
129 u8 *out_report, size_t len)
130{
131 u8 *buf;
132 int ret;
133
134 buf = kmemdup(out_report, len, GFP_KERNEL);
135 if (!buf)
136 return -ENOMEM;
137
138 /* mcp2221 uses interrupt endpoint for out reports */
139 ret = hid_hw_output_report(mcp->hdev, buf, len);
140 kfree(buf);
141
142 if (ret < 0)
143 return ret;
144 return 0;
145}
146
147/*
148 * Send o/p report to the device and wait for i/p report to be
149 * received from the device. If the device does not respond,
150 * we timeout.
151 */
152static int mcp_send_data_req_status(struct mcp2221 *mcp,
153 u8 *out_report, int len)
154{
155 int ret;
156 unsigned long t;
157
158 reinit_completion(&mcp->wait_in_report);
159
160 ret = mcp_send_report(mcp, out_report, len);
161 if (ret)
162 return ret;
163
164 t = wait_for_completion_timeout(&mcp->wait_in_report,
165 msecs_to_jiffies(4000));
166 if (!t)
167 return -ETIMEDOUT;
168
169 return mcp->status;
170}
171
172/* Check pass/fail for actual communication with i2c slave */
173static int mcp_chk_last_cmd_status(struct mcp2221 *mcp)
174{
175 memset(mcp->txbuf, 0, 8);
176 mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
177
178 return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
179}
180
181/* Cancels last command releasing i2c bus just in case occupied */
182static int mcp_cancel_last_cmd(struct mcp2221 *mcp)
183{
184 memset(mcp->txbuf, 0, 8);
185 mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
186 mcp->txbuf[2] = MCP2221_I2C_CANCEL;
187
188 return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
189}
190
191/* Check if the last command succeeded or failed and return the result.
192 * If the command did fail, cancel that command which will free the i2c bus.
193 */
194static int mcp_chk_last_cmd_status_free_bus(struct mcp2221 *mcp)
195{
196 int ret;
197
198 ret = mcp_chk_last_cmd_status(mcp);
199 if (ret) {
200 /* The last command was a failure.
201 * Send a cancel which will also free the bus.
202 */
203 usleep_range(980, 1000);
204 mcp_cancel_last_cmd(mcp);
205 }
206
207 return ret;
208}
209
210static int mcp_set_i2c_speed(struct mcp2221 *mcp)
211{
212 int ret;
213
214 memset(mcp->txbuf, 0, 8);
215 mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
216 mcp->txbuf[3] = MCP2221_I2C_SET_SPEED;
217 mcp->txbuf[4] = mcp->cur_i2c_clk_div;
218
219 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 8);
220 if (ret) {
221 /* Small delay is needed here */
222 usleep_range(980, 1000);
223 mcp_cancel_last_cmd(mcp);
224 }
225
226 return 0;
227}
228
229/*
230 * An output report can contain minimum 1 and maximum 60 user data
231 * bytes. If the number of data bytes is more then 60, we send it
232 * in chunks of 60 bytes. Last chunk may contain exactly 60 or less
233 * bytes. Total number of bytes is informed in very first report to
234 * mcp2221, from that point onwards it first collect all the data
235 * from host and then send to i2c slave device.
236 */
237static int mcp_i2c_write(struct mcp2221 *mcp,
238 struct i2c_msg *msg, int type, u8 last_status)
239{
240 int ret, len, idx, sent;
241
242 idx = 0;
243 sent = 0;
244 if (msg->len < 60)
245 len = msg->len;
246 else
247 len = 60;
248
249 do {
250 mcp->txbuf[0] = type;
251 mcp->txbuf[1] = msg->len & 0xff;
252 mcp->txbuf[2] = msg->len >> 8;
253 mcp->txbuf[3] = (u8)(msg->addr << 1);
254
255 memcpy(&mcp->txbuf[4], &msg->buf[idx], len);
256
257 ret = mcp_send_data_req_status(mcp, mcp->txbuf, len + 4);
258 if (ret)
259 return ret;
260
261 usleep_range(980, 1000);
262
263 if (last_status) {
264 ret = mcp_chk_last_cmd_status_free_bus(mcp);
265 if (ret)
266 return ret;
267 }
268
269 sent = sent + len;
270 if (sent >= msg->len)
271 break;
272
273 idx = idx + len;
274 if ((msg->len - sent) < 60)
275 len = msg->len - sent;
276 else
277 len = 60;
278
279 /*
280 * Testing shows delay is needed between successive writes
281 * otherwise next write fails on first-try from i2c core.
282 * This value is obtained through automated stress testing.
283 */
284 usleep_range(980, 1000);
285 } while (len > 0);
286
287 return ret;
288}
289
290/*
291 * Device reads all data (0 - 65535 bytes) from i2c slave device and
292 * stores it in device itself. This data is read back from device to
293 * host in multiples of 60 bytes using input reports.
294 */
295static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
296 struct i2c_msg *msg, int type, u16 smbus_addr,
297 u8 smbus_len, u8 *smbus_buf)
298{
299 int ret;
300 u16 total_len;
301 int retries = 0;
302
303 mcp->txbuf[0] = type;
304 if (msg) {
305 mcp->txbuf[1] = msg->len & 0xff;
306 mcp->txbuf[2] = msg->len >> 8;
307 mcp->txbuf[3] = (u8)(msg->addr << 1);
308 total_len = msg->len;
309 mcp->rxbuf = msg->buf;
310 } else {
311 mcp->txbuf[1] = smbus_len;
312 mcp->txbuf[2] = 0;
313 mcp->txbuf[3] = (u8)(smbus_addr << 1);
314 total_len = smbus_len;
315 mcp->rxbuf = smbus_buf;
316 }
317
318 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4);
319 if (ret)
320 return ret;
321
322 mcp->rxbuf_idx = 0;
323
324 do {
325 /* Wait for the data to be read by the device */
326 usleep_range(980, 1000);
327
328 memset(mcp->txbuf, 0, 4);
329 mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
330
331 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
332 if (ret) {
333 if (retries < 5) {
334 /* The data wasn't ready to read.
335 * Wait a bit longer and try again.
336 */
337 usleep_range(90, 100);
338 retries++;
339 } else {
340 return ret;
341 }
342 } else {
343 retries = 0;
344 }
345 } while (mcp->rxbuf_idx < total_len);
346
347 usleep_range(980, 1000);
348 ret = mcp_chk_last_cmd_status_free_bus(mcp);
349
350 return ret;
351}
352
353static int mcp_i2c_xfer(struct i2c_adapter *adapter,
354 struct i2c_msg msgs[], int num)
355{
356 int ret;
357 struct mcp2221 *mcp = i2c_get_adapdata(adapter);
358
359 hid_hw_power(mcp->hdev, PM_HINT_FULLON);
360
361 mutex_lock(&mcp->lock);
362
363 if (num == 1) {
364 if (msgs->flags & I2C_M_RD) {
365 ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA,
366 0, 0, NULL);
367 } else {
368 ret = mcp_i2c_write(mcp, msgs, MCP2221_I2C_WR_DATA, 1);
369 }
370 if (ret)
371 goto exit;
372 ret = num;
373 } else if (num == 2) {
374 /* Ex transaction; send reg address and read its contents */
375 if (msgs[0].addr == msgs[1].addr &&
376 !(msgs[0].flags & I2C_M_RD) &&
377 (msgs[1].flags & I2C_M_RD)) {
378
379 ret = mcp_i2c_write(mcp, &msgs[0],
380 MCP2221_I2C_WR_NO_STOP, 0);
381 if (ret)
382 goto exit;
383
384 ret = mcp_i2c_smbus_read(mcp, &msgs[1],
385 MCP2221_I2C_RD_RPT_START,
386 0, 0, NULL);
387 if (ret)
388 goto exit;
389 ret = num;
390 } else {
391 dev_err(&adapter->dev,
392 "unsupported multi-msg i2c transaction\n");
393 ret = -EOPNOTSUPP;
394 }
395 } else {
396 dev_err(&adapter->dev,
397 "unsupported multi-msg i2c transaction\n");
398 ret = -EOPNOTSUPP;
399 }
400
401exit:
402 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
403 mutex_unlock(&mcp->lock);
404 return ret;
405}
406
407static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
408 u8 command, u8 *buf, u8 len, int type,
409 u8 last_status)
410{
411 int data_len, ret;
412
413 mcp->txbuf[0] = type;
414 mcp->txbuf[1] = len + 1; /* 1 is due to command byte itself */
415 mcp->txbuf[2] = 0;
416 mcp->txbuf[3] = (u8)(addr << 1);
417 mcp->txbuf[4] = command;
418
419 switch (len) {
420 case 0:
421 data_len = 5;
422 break;
423 case 1:
424 mcp->txbuf[5] = buf[0];
425 data_len = 6;
426 break;
427 case 2:
428 mcp->txbuf[5] = buf[0];
429 mcp->txbuf[6] = buf[1];
430 data_len = 7;
431 break;
432 default:
433 if (len > I2C_SMBUS_BLOCK_MAX)
434 return -EINVAL;
435
436 memcpy(&mcp->txbuf[5], buf, len);
437 data_len = len + 5;
438 }
439
440 ret = mcp_send_data_req_status(mcp, mcp->txbuf, data_len);
441 if (ret)
442 return ret;
443
444 if (last_status) {
445 usleep_range(980, 1000);
446
447 ret = mcp_chk_last_cmd_status_free_bus(mcp);
448 }
449
450 return ret;
451}
452
453static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
454 unsigned short flags, char read_write,
455 u8 command, int size,
456 union i2c_smbus_data *data)
457{
458 int ret;
459 struct mcp2221 *mcp = i2c_get_adapdata(adapter);
460
461 hid_hw_power(mcp->hdev, PM_HINT_FULLON);
462
463 mutex_lock(&mcp->lock);
464
465 switch (size) {
466
467 case I2C_SMBUS_QUICK:
468 if (read_write == I2C_SMBUS_READ)
469 ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
470 addr, 0, &data->byte);
471 else
472 ret = mcp_smbus_write(mcp, addr, command, NULL,
473 0, MCP2221_I2C_WR_DATA, 1);
474 break;
475 case I2C_SMBUS_BYTE:
476 if (read_write == I2C_SMBUS_READ)
477 ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
478 addr, 1, &data->byte);
479 else
480 ret = mcp_smbus_write(mcp, addr, command, NULL,
481 0, MCP2221_I2C_WR_DATA, 1);
482 break;
483 case I2C_SMBUS_BYTE_DATA:
484 if (read_write == I2C_SMBUS_READ) {
485 ret = mcp_smbus_write(mcp, addr, command, NULL,
486 0, MCP2221_I2C_WR_NO_STOP, 0);
487 if (ret)
488 goto exit;
489
490 ret = mcp_i2c_smbus_read(mcp, NULL,
491 MCP2221_I2C_RD_RPT_START,
492 addr, 1, &data->byte);
493 } else {
494 ret = mcp_smbus_write(mcp, addr, command, &data->byte,
495 1, MCP2221_I2C_WR_DATA, 1);
496 }
497 break;
498 case I2C_SMBUS_WORD_DATA:
499 if (read_write == I2C_SMBUS_READ) {
500 ret = mcp_smbus_write(mcp, addr, command, NULL,
501 0, MCP2221_I2C_WR_NO_STOP, 0);
502 if (ret)
503 goto exit;
504
505 ret = mcp_i2c_smbus_read(mcp, NULL,
506 MCP2221_I2C_RD_RPT_START,
507 addr, 2, (u8 *)&data->word);
508 } else {
509 ret = mcp_smbus_write(mcp, addr, command,
510 (u8 *)&data->word, 2,
511 MCP2221_I2C_WR_DATA, 1);
512 }
513 break;
514 case I2C_SMBUS_BLOCK_DATA:
515 if (read_write == I2C_SMBUS_READ) {
516 ret = mcp_smbus_write(mcp, addr, command, NULL,
517 0, MCP2221_I2C_WR_NO_STOP, 1);
518 if (ret)
519 goto exit;
520
521 mcp->rxbuf_idx = 0;
522 mcp->rxbuf = data->block;
523 mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
524 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
525 if (ret)
526 goto exit;
527 } else {
528 if (!data->block[0]) {
529 ret = -EINVAL;
530 goto exit;
531 }
532 ret = mcp_smbus_write(mcp, addr, command, data->block,
533 data->block[0] + 1,
534 MCP2221_I2C_WR_DATA, 1);
535 }
536 break;
537 case I2C_SMBUS_I2C_BLOCK_DATA:
538 if (read_write == I2C_SMBUS_READ) {
539 ret = mcp_smbus_write(mcp, addr, command, NULL,
540 0, MCP2221_I2C_WR_NO_STOP, 1);
541 if (ret)
542 goto exit;
543
544 mcp->rxbuf_idx = 0;
545 mcp->rxbuf = data->block;
546 mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
547 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
548 if (ret)
549 goto exit;
550 } else {
551 if (!data->block[0]) {
552 ret = -EINVAL;
553 goto exit;
554 }
555 ret = mcp_smbus_write(mcp, addr, command,
556 &data->block[1], data->block[0],
557 MCP2221_I2C_WR_DATA, 1);
558 }
559 break;
560 case I2C_SMBUS_PROC_CALL:
561 ret = mcp_smbus_write(mcp, addr, command,
562 (u8 *)&data->word,
563 2, MCP2221_I2C_WR_NO_STOP, 0);
564 if (ret)
565 goto exit;
566
567 ret = mcp_i2c_smbus_read(mcp, NULL,
568 MCP2221_I2C_RD_RPT_START,
569 addr, 2, (u8 *)&data->word);
570 break;
571 case I2C_SMBUS_BLOCK_PROC_CALL:
572 ret = mcp_smbus_write(mcp, addr, command, data->block,
573 data->block[0] + 1,
574 MCP2221_I2C_WR_NO_STOP, 0);
575 if (ret)
576 goto exit;
577
578 ret = mcp_i2c_smbus_read(mcp, NULL,
579 MCP2221_I2C_RD_RPT_START,
580 addr, I2C_SMBUS_BLOCK_MAX,
581 data->block);
582 break;
583 default:
584 dev_err(&mcp->adapter.dev,
585 "unsupported smbus transaction size:%d\n", size);
586 ret = -EOPNOTSUPP;
587 }
588
589exit:
590 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
591 mutex_unlock(&mcp->lock);
592 return ret;
593}
594
595static u32 mcp_i2c_func(struct i2c_adapter *adapter)
596{
597 return I2C_FUNC_I2C |
598 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
599 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
600 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_PEC);
601}
602
603static const struct i2c_algorithm mcp_i2c_algo = {
604 .master_xfer = mcp_i2c_xfer,
605 .smbus_xfer = mcp_smbus_xfer,
606 .functionality = mcp_i2c_func,
607};
608
609#if IS_REACHABLE(CONFIG_GPIOLIB)
610static int mcp_gpio_get(struct gpio_chip *gc,
611 unsigned int offset)
612{
613 int ret;
614 struct mcp2221 *mcp = gpiochip_get_data(gc);
615
616 mcp->txbuf[0] = MCP2221_GPIO_GET;
617
618 mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset]);
619
620 mutex_lock(&mcp->lock);
621 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
622 mutex_unlock(&mcp->lock);
623
624 return ret;
625}
626
627static void mcp_gpio_set(struct gpio_chip *gc,
628 unsigned int offset, int value)
629{
630 struct mcp2221 *mcp = gpiochip_get_data(gc);
631
632 memset(mcp->txbuf, 0, 18);
633 mcp->txbuf[0] = MCP2221_GPIO_SET;
634
635 mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].value);
636
637 mcp->txbuf[mcp->gp_idx - 1] = 1;
638 mcp->txbuf[mcp->gp_idx] = !!value;
639
640 mutex_lock(&mcp->lock);
641 mcp_send_data_req_status(mcp, mcp->txbuf, 18);
642 mutex_unlock(&mcp->lock);
643}
644
645static int mcp_gpio_dir_set(struct mcp2221 *mcp,
646 unsigned int offset, u8 val)
647{
648 memset(mcp->txbuf, 0, 18);
649 mcp->txbuf[0] = MCP2221_GPIO_SET;
650
651 mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].direction);
652
653 mcp->txbuf[mcp->gp_idx - 1] = 1;
654 mcp->txbuf[mcp->gp_idx] = val;
655
656 return mcp_send_data_req_status(mcp, mcp->txbuf, 18);
657}
658
659static int mcp_gpio_direction_input(struct gpio_chip *gc,
660 unsigned int offset)
661{
662 int ret;
663 struct mcp2221 *mcp = gpiochip_get_data(gc);
664
665 mutex_lock(&mcp->lock);
666 ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_IN);
667 mutex_unlock(&mcp->lock);
668
669 return ret;
670}
671
672static int mcp_gpio_direction_output(struct gpio_chip *gc,
673 unsigned int offset, int value)
674{
675 int ret;
676 struct mcp2221 *mcp = gpiochip_get_data(gc);
677
678 mutex_lock(&mcp->lock);
679 ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_OUT);
680 mutex_unlock(&mcp->lock);
681
682 /* Can't configure as output, bailout early */
683 if (ret)
684 return ret;
685
686 mcp_gpio_set(gc, offset, value);
687
688 return 0;
689}
690
691static int mcp_gpio_get_direction(struct gpio_chip *gc,
692 unsigned int offset)
693{
694 int ret;
695 struct mcp2221 *mcp = gpiochip_get_data(gc);
696
697 mcp->txbuf[0] = MCP2221_GPIO_GET;
698
699 mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset]);
700
701 mutex_lock(&mcp->lock);
702 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
703 mutex_unlock(&mcp->lock);
704
705 if (ret)
706 return ret;
707
708 if (mcp->gpio_dir == MCP2221_DIR_IN)
709 return GPIO_LINE_DIRECTION_IN;
710
711 return GPIO_LINE_DIRECTION_OUT;
712}
713#endif
714
715/* Gives current state of i2c engine inside mcp2221 */
716static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
717 u8 *data, u8 idx)
718{
719 int ret;
720
721 switch (data[idx]) {
722 case MCP2221_I2C_WRADDRL_NACK:
723 case MCP2221_I2C_WRADDRL_SEND:
724 ret = -ENXIO;
725 break;
726 case MCP2221_I2C_START_TOUT:
727 case MCP2221_I2C_STOP_TOUT:
728 case MCP2221_I2C_WRADDRL_TOUT:
729 case MCP2221_I2C_WRDATA_TOUT:
730 ret = -ETIMEDOUT;
731 break;
732 case MCP2221_I2C_ENG_BUSY:
733 ret = -EAGAIN;
734 break;
735 case MCP2221_SUCCESS:
736 ret = 0x00;
737 break;
738 default:
739 ret = -EIO;
740 }
741
742 return ret;
743}
744
745/*
746 * MCP2221 uses interrupt endpoint for input reports. This function
747 * is called by HID layer when it receives i/p report from mcp2221,
748 * which is actually a response to the previously sent command.
749 *
750 * MCP2221A firmware specific return codes are parsed and 0 or
751 * appropriate negative error code is returned. Delayed response
752 * results in timeout error and stray reponses results in -EIO.
753 */
754static int mcp2221_raw_event(struct hid_device *hdev,
755 struct hid_report *report, u8 *data, int size)
756{
757 u8 *buf;
758 struct mcp2221 *mcp = hid_get_drvdata(hdev);
759
760 switch (data[0]) {
761
762 case MCP2221_I2C_WR_DATA:
763 case MCP2221_I2C_WR_NO_STOP:
764 case MCP2221_I2C_RD_DATA:
765 case MCP2221_I2C_RD_RPT_START:
766 switch (data[1]) {
767 case MCP2221_SUCCESS:
768 mcp->status = 0;
769 break;
770 default:
771 mcp->status = mcp_get_i2c_eng_state(mcp, data, 2);
772 }
773 complete(&mcp->wait_in_report);
774 break;
775
776 case MCP2221_I2C_PARAM_OR_STATUS:
777 switch (data[1]) {
778 case MCP2221_SUCCESS:
779 if ((mcp->txbuf[3] == MCP2221_I2C_SET_SPEED) &&
780 (data[3] != MCP2221_I2C_SET_SPEED)) {
781 mcp->status = -EAGAIN;
782 break;
783 }
784 if (data[20] & MCP2221_I2C_MASK_ADDR_NACK) {
785 mcp->status = -ENXIO;
786 break;
787 }
788 mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
789#if IS_REACHABLE(CONFIG_IIO)
790 memcpy(&mcp->adc_values, &data[50], sizeof(mcp->adc_values));
791#endif
792 break;
793 default:
794 mcp->status = -EIO;
795 }
796 complete(&mcp->wait_in_report);
797 break;
798
799 case MCP2221_I2C_GET_DATA:
800 switch (data[1]) {
801 case MCP2221_SUCCESS:
802 if (data[2] == MCP2221_I2C_ADDR_NACK) {
803 mcp->status = -ENXIO;
804 break;
805 }
806 if (!mcp_get_i2c_eng_state(mcp, data, 2)
807 && (data[3] == 0)) {
808 mcp->status = 0;
809 break;
810 }
811 if (data[3] == 127) {
812 mcp->status = -EIO;
813 break;
814 }
815 if (data[2] == MCP2221_I2C_READ_COMPL ||
816 data[2] == MCP2221_I2C_READ_PARTIAL) {
817 buf = mcp->rxbuf;
818 memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
819 mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
820 mcp->status = 0;
821 break;
822 }
823 mcp->status = -EIO;
824 break;
825 default:
826 mcp->status = -EIO;
827 }
828 complete(&mcp->wait_in_report);
829 break;
830
831 case MCP2221_GPIO_GET:
832 switch (data[1]) {
833 case MCP2221_SUCCESS:
834 if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
835 (data[mcp->gp_idx + 1] == MCP2221_ALT_F_NOT_GPIOD)) {
836 mcp->status = -ENOENT;
837 } else {
838 mcp->status = !!data[mcp->gp_idx];
839 mcp->gpio_dir = data[mcp->gp_idx + 1];
840 }
841 break;
842 default:
843 mcp->status = -EAGAIN;
844 }
845 complete(&mcp->wait_in_report);
846 break;
847
848 case MCP2221_GPIO_SET:
849 switch (data[1]) {
850 case MCP2221_SUCCESS:
851 if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
852 (data[mcp->gp_idx - 1] == MCP2221_ALT_F_NOT_GPIOV)) {
853 mcp->status = -ENOENT;
854 } else {
855 mcp->status = 0;
856 }
857 break;
858 default:
859 mcp->status = -EAGAIN;
860 }
861 complete(&mcp->wait_in_report);
862 break;
863
864 case MCP2221_SET_SRAM_SETTINGS:
865 switch (data[1]) {
866 case MCP2221_SUCCESS:
867 mcp->status = 0;
868 break;
869 default:
870 mcp->status = -EAGAIN;
871 }
872 complete(&mcp->wait_in_report);
873 break;
874
875 case MCP2221_GET_SRAM_SETTINGS:
876 switch (data[1]) {
877 case MCP2221_SUCCESS:
878 memcpy(&mcp->mode, &data[22], 4);
879#if IS_REACHABLE(CONFIG_IIO)
880 mcp->dac_value = data[6] & GENMASK(4, 0);
881#endif
882 mcp->status = 0;
883 break;
884 default:
885 mcp->status = -EAGAIN;
886 }
887 complete(&mcp->wait_in_report);
888 break;
889
890 case MCP2221_READ_FLASH_DATA:
891 switch (data[1]) {
892 case MCP2221_SUCCESS:
893 mcp->status = 0;
894
895 /* Only handles CHIP SETTINGS subpage currently */
896 if (mcp->txbuf[1] != 0) {
897 mcp->status = -EIO;
898 break;
899 }
900
901#if IS_REACHABLE(CONFIG_IIO)
902 {
903 u8 tmp;
904 /* DAC scale value */
905 tmp = FIELD_GET(GENMASK(7, 6), data[6]);
906 if ((data[6] & BIT(5)) && tmp)
907 mcp->dac_scale = tmp + 4;
908 else
909 mcp->dac_scale = 5;
910
911 /* ADC scale value */
912 tmp = FIELD_GET(GENMASK(4, 3), data[7]);
913 if ((data[7] & BIT(2)) && tmp)
914 mcp->adc_scale = tmp - 1;
915 else
916 mcp->adc_scale = 0;
917 }
918#endif
919
920 break;
921 default:
922 mcp->status = -EAGAIN;
923 }
924 complete(&mcp->wait_in_report);
925 break;
926
927 default:
928 mcp->status = -EIO;
929 complete(&mcp->wait_in_report);
930 }
931
932 return 1;
933}
934
935/* Device resource managed function for HID unregistration */
936static void mcp2221_hid_unregister(void *ptr)
937{
938 struct hid_device *hdev = ptr;
939
940 hid_hw_close(hdev);
941 hid_hw_stop(hdev);
942}
943
944/* This is needed to be sure hid_hw_stop() isn't called twice by the subsystem */
945static void mcp2221_remove(struct hid_device *hdev)
946{
947 struct mcp2221 *mcp = hid_get_drvdata(hdev);
948
949 cancel_delayed_work_sync(&mcp->init_work);
950}
951
952#if IS_REACHABLE(CONFIG_IIO)
953static int mcp2221_read_raw(struct iio_dev *indio_dev,
954 struct iio_chan_spec const *channel, int *val,
955 int *val2, long mask)
956{
957 struct mcp2221_iio *priv = iio_priv(indio_dev);
958 struct mcp2221 *mcp = priv->mcp;
959 int ret;
960
961 if (mask == IIO_CHAN_INFO_SCALE) {
962 if (channel->output)
963 *val = 1 << mcp->dac_scale;
964 else
965 *val = 1 << mcp->adc_scale;
966
967 return IIO_VAL_INT;
968 }
969
970 mutex_lock(&mcp->lock);
971
972 if (channel->output) {
973 *val = mcp->dac_value;
974 ret = IIO_VAL_INT;
975 } else {
976 /* Read ADC values */
977 ret = mcp_chk_last_cmd_status(mcp);
978
979 if (!ret) {
980 *val = le16_to_cpu((__force __le16) mcp->adc_values[channel->address]);
981 if (*val >= BIT(10))
982 ret = -EINVAL;
983 else
984 ret = IIO_VAL_INT;
985 }
986 }
987
988 mutex_unlock(&mcp->lock);
989
990 return ret;
991}
992
993static int mcp2221_write_raw(struct iio_dev *indio_dev,
994 struct iio_chan_spec const *chan,
995 int val, int val2, long mask)
996{
997 struct mcp2221_iio *priv = iio_priv(indio_dev);
998 struct mcp2221 *mcp = priv->mcp;
999 int ret;
1000
1001 if (val < 0 || val >= BIT(5))
1002 return -EINVAL;
1003
1004 mutex_lock(&mcp->lock);
1005
1006 memset(mcp->txbuf, 0, 12);
1007 mcp->txbuf[0] = MCP2221_SET_SRAM_SETTINGS;
1008 mcp->txbuf[4] = BIT(7) | val;
1009
1010 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 12);
1011 if (!ret)
1012 mcp->dac_value = val;
1013
1014 mutex_unlock(&mcp->lock);
1015
1016 return ret;
1017}
1018
1019static const struct iio_info mcp2221_info = {
1020 .read_raw = &mcp2221_read_raw,
1021 .write_raw = &mcp2221_write_raw,
1022};
1023
1024static int mcp_iio_channels(struct mcp2221 *mcp)
1025{
1026 int idx, cnt = 0;
1027 bool dac_created = false;
1028
1029 /* GP0 doesn't have ADC/DAC alternative function */
1030 for (idx = 1; idx < MCP_NGPIO; idx++) {
1031 struct iio_chan_spec *chan = &mcp->iio_channels[cnt];
1032
1033 switch (mcp->mode[idx]) {
1034 case 2:
1035 chan->address = idx - 1;
1036 chan->channel = cnt++;
1037 break;
1038 case 3:
1039 /* GP1 doesn't have DAC alternative function */
1040 if (idx == 1 || dac_created)
1041 continue;
1042 /* DAC1 and DAC2 outputs are connected to the same DAC */
1043 dac_created = true;
1044 chan->output = 1;
1045 cnt++;
1046 break;
1047 default:
1048 continue;
1049 };
1050
1051 chan->type = IIO_VOLTAGE;
1052 chan->indexed = 1;
1053 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
1054 chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
1055 chan->scan_index = -1;
1056 }
1057
1058 return cnt;
1059}
1060
1061static void mcp_init_work(struct work_struct *work)
1062{
1063 struct iio_dev *indio_dev;
1064 struct mcp2221 *mcp = container_of(work, struct mcp2221, init_work.work);
1065 struct mcp2221_iio *data;
1066 static int retries = 5;
1067 int ret, num_channels;
1068
1069 hid_hw_power(mcp->hdev, PM_HINT_FULLON);
1070 mutex_lock(&mcp->lock);
1071
1072 mcp->txbuf[0] = MCP2221_GET_SRAM_SETTINGS;
1073 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
1074
1075 if (ret == -EAGAIN)
1076 goto reschedule_task;
1077
1078 num_channels = mcp_iio_channels(mcp);
1079 if (!num_channels)
1080 goto unlock;
1081
1082 mcp->txbuf[0] = MCP2221_READ_FLASH_DATA;
1083 mcp->txbuf[1] = 0;
1084 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 2);
1085
1086 if (ret == -EAGAIN)
1087 goto reschedule_task;
1088
1089 indio_dev = devm_iio_device_alloc(&mcp->hdev->dev, sizeof(*data));
1090 if (!indio_dev)
1091 goto unlock;
1092
1093 data = iio_priv(indio_dev);
1094 data->mcp = mcp;
1095
1096 indio_dev->name = "mcp2221";
1097 indio_dev->modes = INDIO_DIRECT_MODE;
1098 indio_dev->info = &mcp2221_info;
1099 indio_dev->channels = mcp->iio_channels;
1100 indio_dev->num_channels = num_channels;
1101
1102 devm_iio_device_register(&mcp->hdev->dev, indio_dev);
1103
1104unlock:
1105 mutex_unlock(&mcp->lock);
1106 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
1107
1108 return;
1109
1110reschedule_task:
1111 mutex_unlock(&mcp->lock);
1112 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
1113
1114 if (!retries--)
1115 return;
1116
1117 /* Device is not ready to read SRAM or FLASH data, try again */
1118 schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
1119}
1120#endif
1121
1122static int mcp2221_probe(struct hid_device *hdev,
1123 const struct hid_device_id *id)
1124{
1125 int ret;
1126 struct mcp2221 *mcp;
1127
1128 mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
1129 if (!mcp)
1130 return -ENOMEM;
1131
1132 ret = hid_parse(hdev);
1133 if (ret) {
1134 hid_err(hdev, "can't parse reports\n");
1135 return ret;
1136 }
1137
1138 /*
1139 * This driver uses the .raw_event callback and therefore does not need any
1140 * HID_CONNECT_xxx flags.
1141 */
1142 ret = hid_hw_start(hdev, 0);
1143 if (ret) {
1144 hid_err(hdev, "can't start hardware\n");
1145 return ret;
1146 }
1147
1148 hid_info(hdev, "USB HID v%x.%02x Device [%s] on %s\n", hdev->version >> 8,
1149 hdev->version & 0xff, hdev->name, hdev->phys);
1150
1151 ret = hid_hw_open(hdev);
1152 if (ret) {
1153 hid_err(hdev, "can't open device\n");
1154 hid_hw_stop(hdev);
1155 return ret;
1156 }
1157
1158 mutex_init(&mcp->lock);
1159 init_completion(&mcp->wait_in_report);
1160 hid_set_drvdata(hdev, mcp);
1161 mcp->hdev = hdev;
1162
1163 ret = devm_add_action_or_reset(&hdev->dev, mcp2221_hid_unregister, hdev);
1164 if (ret)
1165 return ret;
1166
1167 hid_device_io_start(hdev);
1168
1169 /* Set I2C bus clock diviser */
1170 if (i2c_clk_freq > 400)
1171 i2c_clk_freq = 400;
1172 if (i2c_clk_freq < 50)
1173 i2c_clk_freq = 50;
1174 mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
1175 ret = mcp_set_i2c_speed(mcp);
1176 if (ret) {
1177 hid_err(hdev, "can't set i2c speed: %d\n", ret);
1178 return ret;
1179 }
1180
1181 mcp->adapter.owner = THIS_MODULE;
1182 mcp->adapter.class = I2C_CLASS_HWMON;
1183 mcp->adapter.algo = &mcp_i2c_algo;
1184 mcp->adapter.retries = 1;
1185 mcp->adapter.dev.parent = &hdev->dev;
1186 ACPI_COMPANION_SET(&mcp->adapter.dev, ACPI_COMPANION(hdev->dev.parent));
1187 snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
1188 "MCP2221 usb-i2c bridge");
1189
1190 i2c_set_adapdata(&mcp->adapter, mcp);
1191 ret = devm_i2c_add_adapter(&hdev->dev, &mcp->adapter);
1192 if (ret) {
1193 hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
1194 return ret;
1195 }
1196
1197#if IS_REACHABLE(CONFIG_GPIOLIB)
1198 /* Setup GPIO chip */
1199 mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);
1200 if (!mcp->gc)
1201 return -ENOMEM;
1202
1203 mcp->gc->label = "mcp2221_gpio";
1204 mcp->gc->direction_input = mcp_gpio_direction_input;
1205 mcp->gc->direction_output = mcp_gpio_direction_output;
1206 mcp->gc->get_direction = mcp_gpio_get_direction;
1207 mcp->gc->set = mcp_gpio_set;
1208 mcp->gc->get = mcp_gpio_get;
1209 mcp->gc->ngpio = MCP_NGPIO;
1210 mcp->gc->base = -1;
1211 mcp->gc->can_sleep = 1;
1212 mcp->gc->parent = &hdev->dev;
1213
1214 ret = devm_gpiochip_add_data(&hdev->dev, mcp->gc, mcp);
1215 if (ret)
1216 return ret;
1217#endif
1218
1219#if IS_REACHABLE(CONFIG_IIO)
1220 INIT_DELAYED_WORK(&mcp->init_work, mcp_init_work);
1221 schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
1222#endif
1223
1224 return 0;
1225}
1226
1227static const struct hid_device_id mcp2221_devices[] = {
1228 { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
1229 { }
1230};
1231MODULE_DEVICE_TABLE(hid, mcp2221_devices);
1232
1233static struct hid_driver mcp2221_driver = {
1234 .name = "mcp2221",
1235 .id_table = mcp2221_devices,
1236 .probe = mcp2221_probe,
1237 .remove = mcp2221_remove,
1238 .raw_event = mcp2221_raw_event,
1239};
1240
1241/* Register with HID core */
1242module_hid_driver(mcp2221_driver);
1243
1244MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
1245MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
1246MODULE_LICENSE("GPL v2");