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

source code of linux/drivers/hid/hid-mcp2221.c