tjh.dev
Linux kernel mirror (for testing)
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linux
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 int mcp_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
628{
629 struct mcp2221 *mcp = gpiochip_get_data(gc);
630 int ret;
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 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 18);
642 mutex_unlock(&mcp->lock);
643
644 return ret;
645}
646
647static int mcp_gpio_dir_set(struct mcp2221 *mcp,
648 unsigned int offset, u8 val)
649{
650 memset(mcp->txbuf, 0, 18);
651 mcp->txbuf[0] = MCP2221_GPIO_SET;
652
653 mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].direction);
654
655 mcp->txbuf[mcp->gp_idx - 1] = 1;
656 mcp->txbuf[mcp->gp_idx] = val;
657
658 return mcp_send_data_req_status(mcp, mcp->txbuf, 18);
659}
660
661static int mcp_gpio_direction_input(struct gpio_chip *gc,
662 unsigned int offset)
663{
664 int ret;
665 struct mcp2221 *mcp = gpiochip_get_data(gc);
666
667 mutex_lock(&mcp->lock);
668 ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_IN);
669 mutex_unlock(&mcp->lock);
670
671 return ret;
672}
673
674static int mcp_gpio_direction_output(struct gpio_chip *gc,
675 unsigned int offset, int value)
676{
677 int ret;
678 struct mcp2221 *mcp = gpiochip_get_data(gc);
679
680 mutex_lock(&mcp->lock);
681 ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_OUT);
682 mutex_unlock(&mcp->lock);
683
684 /* Can't configure as output, bailout early */
685 if (ret)
686 return ret;
687
688 mcp_gpio_set(gc, offset, value);
689
690 return 0;
691}
692
693static int mcp_gpio_get_direction(struct gpio_chip *gc,
694 unsigned int offset)
695{
696 int ret;
697 struct mcp2221 *mcp = gpiochip_get_data(gc);
698
699 mcp->txbuf[0] = MCP2221_GPIO_GET;
700
701 mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset]);
702
703 mutex_lock(&mcp->lock);
704 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
705 mutex_unlock(&mcp->lock);
706
707 if (ret)
708 return ret;
709
710 if (mcp->gpio_dir == MCP2221_DIR_IN)
711 return GPIO_LINE_DIRECTION_IN;
712
713 return GPIO_LINE_DIRECTION_OUT;
714}
715#endif
716
717/* Gives current state of i2c engine inside mcp2221 */
718static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
719 u8 *data, u8 idx)
720{
721 int ret;
722
723 switch (data[idx]) {
724 case MCP2221_I2C_WRADDRL_NACK:
725 case MCP2221_I2C_WRADDRL_SEND:
726 ret = -ENXIO;
727 break;
728 case MCP2221_I2C_START_TOUT:
729 case MCP2221_I2C_STOP_TOUT:
730 case MCP2221_I2C_WRADDRL_TOUT:
731 case MCP2221_I2C_WRDATA_TOUT:
732 ret = -ETIMEDOUT;
733 break;
734 case MCP2221_I2C_ENG_BUSY:
735 ret = -EAGAIN;
736 break;
737 case MCP2221_SUCCESS:
738 ret = 0x00;
739 break;
740 default:
741 ret = -EIO;
742 }
743
744 return ret;
745}
746
747/*
748 * MCP2221 uses interrupt endpoint for input reports. This function
749 * is called by HID layer when it receives i/p report from mcp2221,
750 * which is actually a response to the previously sent command.
751 *
752 * MCP2221A firmware specific return codes are parsed and 0 or
753 * appropriate negative error code is returned. Delayed response
754 * results in timeout error and stray reponses results in -EIO.
755 */
756static int mcp2221_raw_event(struct hid_device *hdev,
757 struct hid_report *report, u8 *data, int size)
758{
759 u8 *buf;
760 struct mcp2221 *mcp = hid_get_drvdata(hdev);
761
762 switch (data[0]) {
763
764 case MCP2221_I2C_WR_DATA:
765 case MCP2221_I2C_WR_NO_STOP:
766 case MCP2221_I2C_RD_DATA:
767 case MCP2221_I2C_RD_RPT_START:
768 switch (data[1]) {
769 case MCP2221_SUCCESS:
770 mcp->status = 0;
771 break;
772 default:
773 mcp->status = mcp_get_i2c_eng_state(mcp, data, 2);
774 }
775 complete(&mcp->wait_in_report);
776 break;
777
778 case MCP2221_I2C_PARAM_OR_STATUS:
779 switch (data[1]) {
780 case MCP2221_SUCCESS:
781 if ((mcp->txbuf[3] == MCP2221_I2C_SET_SPEED) &&
782 (data[3] != MCP2221_I2C_SET_SPEED)) {
783 mcp->status = -EAGAIN;
784 break;
785 }
786 if (data[20] & MCP2221_I2C_MASK_ADDR_NACK) {
787 mcp->status = -ENXIO;
788 break;
789 }
790 mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
791#if IS_REACHABLE(CONFIG_IIO)
792 memcpy(&mcp->adc_values, &data[50], sizeof(mcp->adc_values));
793#endif
794 break;
795 default:
796 mcp->status = -EIO;
797 }
798 complete(&mcp->wait_in_report);
799 break;
800
801 case MCP2221_I2C_GET_DATA:
802 switch (data[1]) {
803 case MCP2221_SUCCESS:
804 if (data[2] == MCP2221_I2C_ADDR_NACK) {
805 mcp->status = -ENXIO;
806 break;
807 }
808 if (!mcp_get_i2c_eng_state(mcp, data, 2)
809 && (data[3] == 0)) {
810 mcp->status = 0;
811 break;
812 }
813 if (data[3] == 127) {
814 mcp->status = -EIO;
815 break;
816 }
817 if (data[2] == MCP2221_I2C_READ_COMPL ||
818 data[2] == MCP2221_I2C_READ_PARTIAL) {
819 buf = mcp->rxbuf;
820 memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
821 mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
822 mcp->status = 0;
823 break;
824 }
825 mcp->status = -EIO;
826 break;
827 default:
828 mcp->status = -EIO;
829 }
830 complete(&mcp->wait_in_report);
831 break;
832
833 case MCP2221_GPIO_GET:
834 switch (data[1]) {
835 case MCP2221_SUCCESS:
836 if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
837 (data[mcp->gp_idx + 1] == MCP2221_ALT_F_NOT_GPIOD)) {
838 mcp->status = -ENOENT;
839 } else {
840 mcp->status = !!data[mcp->gp_idx];
841 mcp->gpio_dir = data[mcp->gp_idx + 1];
842 }
843 break;
844 default:
845 mcp->status = -EAGAIN;
846 }
847 complete(&mcp->wait_in_report);
848 break;
849
850 case MCP2221_GPIO_SET:
851 switch (data[1]) {
852 case MCP2221_SUCCESS:
853 if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
854 (data[mcp->gp_idx - 1] == MCP2221_ALT_F_NOT_GPIOV)) {
855 mcp->status = -ENOENT;
856 } else {
857 mcp->status = 0;
858 }
859 break;
860 default:
861 mcp->status = -EAGAIN;
862 }
863 complete(&mcp->wait_in_report);
864 break;
865
866 case MCP2221_SET_SRAM_SETTINGS:
867 switch (data[1]) {
868 case MCP2221_SUCCESS:
869 mcp->status = 0;
870 break;
871 default:
872 mcp->status = -EAGAIN;
873 }
874 complete(&mcp->wait_in_report);
875 break;
876
877 case MCP2221_GET_SRAM_SETTINGS:
878 switch (data[1]) {
879 case MCP2221_SUCCESS:
880 memcpy(&mcp->mode, &data[22], 4);
881#if IS_REACHABLE(CONFIG_IIO)
882 mcp->dac_value = data[6] & GENMASK(4, 0);
883#endif
884 mcp->status = 0;
885 break;
886 default:
887 mcp->status = -EAGAIN;
888 }
889 complete(&mcp->wait_in_report);
890 break;
891
892 case MCP2221_READ_FLASH_DATA:
893 switch (data[1]) {
894 case MCP2221_SUCCESS:
895 mcp->status = 0;
896
897 /* Only handles CHIP SETTINGS subpage currently */
898 if (mcp->txbuf[1] != 0) {
899 mcp->status = -EIO;
900 break;
901 }
902
903#if IS_REACHABLE(CONFIG_IIO)
904 {
905 u8 tmp;
906 /* DAC scale value */
907 tmp = FIELD_GET(GENMASK(7, 6), data[6]);
908 if ((data[6] & BIT(5)) && tmp)
909 mcp->dac_scale = tmp + 4;
910 else
911 mcp->dac_scale = 5;
912
913 /* ADC scale value */
914 tmp = FIELD_GET(GENMASK(4, 3), data[7]);
915 if ((data[7] & BIT(2)) && tmp)
916 mcp->adc_scale = tmp - 1;
917 else
918 mcp->adc_scale = 0;
919 }
920#endif
921
922 break;
923 default:
924 mcp->status = -EAGAIN;
925 }
926 complete(&mcp->wait_in_report);
927 break;
928
929 default:
930 mcp->status = -EIO;
931 complete(&mcp->wait_in_report);
932 }
933
934 return 1;
935}
936
937/* Device resource managed function for HID unregistration */
938static void mcp2221_hid_unregister(void *ptr)
939{
940 struct hid_device *hdev = ptr;
941
942 hid_hw_close(hdev);
943 hid_hw_stop(hdev);
944}
945
946/* This is needed to be sure hid_hw_stop() isn't called twice by the subsystem */
947static void mcp2221_remove(struct hid_device *hdev)
948{
949#if IS_REACHABLE(CONFIG_IIO)
950 struct mcp2221 *mcp = hid_get_drvdata(hdev);
951
952 cancel_delayed_work_sync(&mcp->init_work);
953#endif
954}
955
956#if IS_REACHABLE(CONFIG_IIO)
957static int mcp2221_read_raw(struct iio_dev *indio_dev,
958 struct iio_chan_spec const *channel, int *val,
959 int *val2, long mask)
960{
961 struct mcp2221_iio *priv = iio_priv(indio_dev);
962 struct mcp2221 *mcp = priv->mcp;
963 int ret;
964
965 if (mask == IIO_CHAN_INFO_SCALE) {
966 if (channel->output)
967 *val = 1 << mcp->dac_scale;
968 else
969 *val = 1 << mcp->adc_scale;
970
971 return IIO_VAL_INT;
972 }
973
974 mutex_lock(&mcp->lock);
975
976 if (channel->output) {
977 *val = mcp->dac_value;
978 ret = IIO_VAL_INT;
979 } else {
980 /* Read ADC values */
981 ret = mcp_chk_last_cmd_status(mcp);
982
983 if (!ret) {
984 *val = le16_to_cpu((__force __le16) mcp->adc_values[channel->address]);
985 if (*val >= BIT(10))
986 ret = -EINVAL;
987 else
988 ret = IIO_VAL_INT;
989 }
990 }
991
992 mutex_unlock(&mcp->lock);
993
994 return ret;
995}
996
997static int mcp2221_write_raw(struct iio_dev *indio_dev,
998 struct iio_chan_spec const *chan,
999 int val, int val2, long mask)
1000{
1001 struct mcp2221_iio *priv = iio_priv(indio_dev);
1002 struct mcp2221 *mcp = priv->mcp;
1003 int ret;
1004
1005 if (val < 0 || val >= BIT(5))
1006 return -EINVAL;
1007
1008 mutex_lock(&mcp->lock);
1009
1010 memset(mcp->txbuf, 0, 12);
1011 mcp->txbuf[0] = MCP2221_SET_SRAM_SETTINGS;
1012 mcp->txbuf[4] = BIT(7) | val;
1013
1014 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 12);
1015 if (!ret)
1016 mcp->dac_value = val;
1017
1018 mutex_unlock(&mcp->lock);
1019
1020 return ret;
1021}
1022
1023static const struct iio_info mcp2221_info = {
1024 .read_raw = &mcp2221_read_raw,
1025 .write_raw = &mcp2221_write_raw,
1026};
1027
1028static int mcp_iio_channels(struct mcp2221 *mcp)
1029{
1030 int idx, cnt = 0;
1031 bool dac_created = false;
1032
1033 /* GP0 doesn't have ADC/DAC alternative function */
1034 for (idx = 1; idx < MCP_NGPIO; idx++) {
1035 struct iio_chan_spec *chan = &mcp->iio_channels[cnt];
1036
1037 switch (mcp->mode[idx]) {
1038 case 2:
1039 chan->address = idx - 1;
1040 chan->channel = cnt++;
1041 break;
1042 case 3:
1043 /* GP1 doesn't have DAC alternative function */
1044 if (idx == 1 || dac_created)
1045 continue;
1046 /* DAC1 and DAC2 outputs are connected to the same DAC */
1047 dac_created = true;
1048 chan->output = 1;
1049 cnt++;
1050 break;
1051 default:
1052 continue;
1053 }
1054
1055 chan->type = IIO_VOLTAGE;
1056 chan->indexed = 1;
1057 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
1058 chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
1059 chan->scan_index = -1;
1060 }
1061
1062 return cnt;
1063}
1064
1065static void mcp_init_work(struct work_struct *work)
1066{
1067 struct iio_dev *indio_dev;
1068 struct mcp2221 *mcp = container_of(work, struct mcp2221, init_work.work);
1069 struct mcp2221_iio *data;
1070 static int retries = 5;
1071 int ret, num_channels;
1072
1073 hid_hw_power(mcp->hdev, PM_HINT_FULLON);
1074 mutex_lock(&mcp->lock);
1075
1076 mcp->txbuf[0] = MCP2221_GET_SRAM_SETTINGS;
1077 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
1078
1079 if (ret == -EAGAIN)
1080 goto reschedule_task;
1081
1082 num_channels = mcp_iio_channels(mcp);
1083 if (!num_channels)
1084 goto unlock;
1085
1086 mcp->txbuf[0] = MCP2221_READ_FLASH_DATA;
1087 mcp->txbuf[1] = 0;
1088 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 2);
1089
1090 if (ret == -EAGAIN)
1091 goto reschedule_task;
1092
1093 indio_dev = devm_iio_device_alloc(&mcp->hdev->dev, sizeof(*data));
1094 if (!indio_dev)
1095 goto unlock;
1096
1097 data = iio_priv(indio_dev);
1098 data->mcp = mcp;
1099
1100 indio_dev->name = "mcp2221";
1101 indio_dev->modes = INDIO_DIRECT_MODE;
1102 indio_dev->info = &mcp2221_info;
1103 indio_dev->channels = mcp->iio_channels;
1104 indio_dev->num_channels = num_channels;
1105
1106 devm_iio_device_register(&mcp->hdev->dev, indio_dev);
1107
1108unlock:
1109 mutex_unlock(&mcp->lock);
1110 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
1111
1112 return;
1113
1114reschedule_task:
1115 mutex_unlock(&mcp->lock);
1116 hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
1117
1118 if (!retries--)
1119 return;
1120
1121 /* Device is not ready to read SRAM or FLASH data, try again */
1122 schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
1123}
1124#endif
1125
1126static int mcp2221_probe(struct hid_device *hdev,
1127 const struct hid_device_id *id)
1128{
1129 int ret;
1130 struct mcp2221 *mcp;
1131
1132 mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
1133 if (!mcp)
1134 return -ENOMEM;
1135
1136 ret = hid_parse(hdev);
1137 if (ret) {
1138 hid_err(hdev, "can't parse reports\n");
1139 return ret;
1140 }
1141
1142 /*
1143 * This driver uses the .raw_event callback and therefore does not need any
1144 * HID_CONNECT_xxx flags.
1145 */
1146 ret = hid_hw_start(hdev, 0);
1147 if (ret) {
1148 hid_err(hdev, "can't start hardware\n");
1149 return ret;
1150 }
1151
1152 hid_info(hdev, "USB HID v%x.%02x Device [%s] on %s\n", hdev->version >> 8,
1153 hdev->version & 0xff, hdev->name, hdev->phys);
1154
1155 ret = hid_hw_open(hdev);
1156 if (ret) {
1157 hid_err(hdev, "can't open device\n");
1158 hid_hw_stop(hdev);
1159 return ret;
1160 }
1161
1162 mutex_init(&mcp->lock);
1163 init_completion(&mcp->wait_in_report);
1164 hid_set_drvdata(hdev, mcp);
1165 mcp->hdev = hdev;
1166
1167 ret = devm_add_action_or_reset(&hdev->dev, mcp2221_hid_unregister, hdev);
1168 if (ret)
1169 return ret;
1170
1171 hid_device_io_start(hdev);
1172
1173 /* Set I2C bus clock diviser */
1174 if (i2c_clk_freq > 400)
1175 i2c_clk_freq = 400;
1176 if (i2c_clk_freq < 50)
1177 i2c_clk_freq = 50;
1178 mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
1179 ret = mcp_set_i2c_speed(mcp);
1180 if (ret) {
1181 hid_err(hdev, "can't set i2c speed: %d\n", ret);
1182 return ret;
1183 }
1184
1185 mcp->adapter.owner = THIS_MODULE;
1186 mcp->adapter.class = I2C_CLASS_HWMON;
1187 mcp->adapter.algo = &mcp_i2c_algo;
1188 mcp->adapter.retries = 1;
1189 mcp->adapter.dev.parent = &hdev->dev;
1190 ACPI_COMPANION_SET(&mcp->adapter.dev, ACPI_COMPANION(hdev->dev.parent));
1191 snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
1192 "MCP2221 usb-i2c bridge");
1193
1194 i2c_set_adapdata(&mcp->adapter, mcp);
1195 ret = devm_i2c_add_adapter(&hdev->dev, &mcp->adapter);
1196 if (ret) {
1197 hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
1198 return ret;
1199 }
1200
1201#if IS_REACHABLE(CONFIG_GPIOLIB)
1202 /* Setup GPIO chip */
1203 mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);
1204 if (!mcp->gc)
1205 return -ENOMEM;
1206
1207 mcp->gc->label = "mcp2221_gpio";
1208 mcp->gc->direction_input = mcp_gpio_direction_input;
1209 mcp->gc->direction_output = mcp_gpio_direction_output;
1210 mcp->gc->get_direction = mcp_gpio_get_direction;
1211 mcp->gc->set_rv = mcp_gpio_set;
1212 mcp->gc->get = mcp_gpio_get;
1213 mcp->gc->ngpio = MCP_NGPIO;
1214 mcp->gc->base = -1;
1215 mcp->gc->can_sleep = 1;
1216 mcp->gc->parent = &hdev->dev;
1217
1218 ret = devm_gpiochip_add_data(&hdev->dev, mcp->gc, mcp);
1219 if (ret)
1220 return ret;
1221#endif
1222
1223#if IS_REACHABLE(CONFIG_IIO)
1224 INIT_DELAYED_WORK(&mcp->init_work, mcp_init_work);
1225 schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
1226#endif
1227
1228 return 0;
1229}
1230
1231static const struct hid_device_id mcp2221_devices[] = {
1232 { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
1233 { }
1234};
1235MODULE_DEVICE_TABLE(hid, mcp2221_devices);
1236
1237static struct hid_driver mcp2221_driver = {
1238 .name = "mcp2221",
1239 .id_table = mcp2221_devices,
1240 .probe = mcp2221_probe,
1241 .remove = mcp2221_remove,
1242 .raw_event = mcp2221_raw_event,
1243};
1244
1245/* Register with HID core */
1246module_hid_driver(mcp2221_driver);
1247
1248MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
1249MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
1250MODULE_LICENSE("GPL v2");