xref: /openbmc/linux/drivers/hid/hid-ft260.c (revision f45d50ede6f9e6d76a218e6ed06cc352acad466f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * hid-ft260.c - FTDI FT260 USB HID to I2C host bridge
4  *
5  * Copyright (c) 2021, Michael Zaidman <michaelz@xsightlabs.com>
6  *
7  * Data Sheet:
8  *   https://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT260.pdf
9  */
10 
11 #include "hid-ids.h"
12 #include <linux/hidraw.h>
13 #include <linux/i2c.h>
14 #include <linux/module.h>
15 #include <linux/usb.h>
16 
17 #ifdef DEBUG
18 static int ft260_debug = 1;
19 #else
20 static int ft260_debug;
21 #endif
22 module_param_named(debug, ft260_debug, int, 0600);
23 MODULE_PARM_DESC(debug, "Toggle FT260 debugging messages");
24 
25 #define ft260_dbg(format, arg...)					  \
26 	do {								  \
27 		if (ft260_debug)					  \
28 			pr_info("%s: " format, __func__, ##arg);	  \
29 	} while (0)
30 
31 #define FT260_REPORT_MAX_LENGTH (64)
32 #define FT260_I2C_DATA_REPORT_ID(len) (FT260_I2C_REPORT_MIN + (len - 1) / 4)
33 /*
34  * The input report format assigns 62 bytes for the data payload, but ft260
35  * returns 60 and 2 in two separate transactions. To minimize transfer time
36  * in reading chunks mode, set the maximum read payload length to 60 bytes.
37  */
38 #define FT260_RD_DATA_MAX (60)
39 #define FT260_WR_DATA_MAX (60)
40 
41 /*
42  * Device interface configuration.
43  * The FT260 has 2 interfaces that are controlled by DCNF0 and DCNF1 pins.
44  * First implementes USB HID to I2C bridge function and
45  * second - USB HID to UART bridge function.
46  */
47 enum {
48 	FT260_MODE_ALL			= 0x00,
49 	FT260_MODE_I2C			= 0x01,
50 	FT260_MODE_UART			= 0x02,
51 	FT260_MODE_BOTH			= 0x03,
52 };
53 
54 /* Control pipe */
55 enum {
56 	FT260_GET_RQST_TYPE		= 0xA1,
57 	FT260_GET_REPORT		= 0x01,
58 	FT260_SET_RQST_TYPE		= 0x21,
59 	FT260_SET_REPORT		= 0x09,
60 	FT260_FEATURE			= 0x03,
61 };
62 
63 /* Report IDs / Feature In */
64 enum {
65 	FT260_CHIP_VERSION		= 0xA0,
66 	FT260_SYSTEM_SETTINGS		= 0xA1,
67 	FT260_I2C_STATUS		= 0xC0,
68 	FT260_I2C_READ_REQ		= 0xC2,
69 	FT260_I2C_REPORT_MIN		= 0xD0,
70 	FT260_I2C_REPORT_MAX		= 0xDE,
71 	FT260_GPIO			= 0xB0,
72 	FT260_UART_INTERRUPT_STATUS	= 0xB1,
73 	FT260_UART_STATUS		= 0xE0,
74 	FT260_UART_RI_DCD_STATUS	= 0xE1,
75 	FT260_UART_REPORT		= 0xF0,
76 };
77 
78 /* Feature Out */
79 enum {
80 	FT260_SET_CLOCK			= 0x01,
81 	FT260_SET_I2C_MODE		= 0x02,
82 	FT260_SET_UART_MODE		= 0x03,
83 	FT260_ENABLE_INTERRUPT		= 0x05,
84 	FT260_SELECT_GPIO2_FUNC		= 0x06,
85 	FT260_ENABLE_UART_DCD_RI	= 0x07,
86 	FT260_SELECT_GPIOA_FUNC		= 0x08,
87 	FT260_SELECT_GPIOG_FUNC		= 0x09,
88 	FT260_SET_INTERRUPT_TRIGGER	= 0x0A,
89 	FT260_SET_SUSPEND_OUT_POLAR	= 0x0B,
90 	FT260_ENABLE_UART_RI_WAKEUP	= 0x0C,
91 	FT260_SET_UART_RI_WAKEUP_CFG	= 0x0D,
92 	FT260_SET_I2C_RESET		= 0x20,
93 	FT260_SET_I2C_CLOCK_SPEED	= 0x22,
94 	FT260_SET_UART_RESET		= 0x40,
95 	FT260_SET_UART_CONFIG		= 0x41,
96 	FT260_SET_UART_BAUD_RATE	= 0x42,
97 	FT260_SET_UART_DATA_BIT		= 0x43,
98 	FT260_SET_UART_PARITY		= 0x44,
99 	FT260_SET_UART_STOP_BIT		= 0x45,
100 	FT260_SET_UART_BREAKING		= 0x46,
101 	FT260_SET_UART_XON_XOFF		= 0x49,
102 };
103 
104 /* Response codes in I2C status report */
105 enum {
106 	FT260_I2C_STATUS_SUCCESS	= 0x00,
107 	FT260_I2C_STATUS_CTRL_BUSY	= 0x01,
108 	FT260_I2C_STATUS_ERROR		= 0x02,
109 	FT260_I2C_STATUS_ADDR_NO_ACK	= 0x04,
110 	FT260_I2C_STATUS_DATA_NO_ACK	= 0x08,
111 	FT260_I2C_STATUS_ARBITR_LOST	= 0x10,
112 	FT260_I2C_STATUS_CTRL_IDLE	= 0x20,
113 	FT260_I2C_STATUS_BUS_BUSY	= 0x40,
114 };
115 
116 /* I2C Conditions flags */
117 enum {
118 	FT260_FLAG_NONE			= 0x00,
119 	FT260_FLAG_START		= 0x02,
120 	FT260_FLAG_START_REPEATED	= 0x03,
121 	FT260_FLAG_STOP			= 0x04,
122 	FT260_FLAG_START_STOP		= 0x06,
123 	FT260_FLAG_START_STOP_REPEATED	= 0x07,
124 };
125 
126 #define FT260_SET_REQUEST_VALUE(report_id) ((FT260_FEATURE << 8) | report_id)
127 
128 /* Feature In reports */
129 
130 struct ft260_get_chip_version_report {
131 	u8 report;		/* FT260_CHIP_VERSION */
132 	u8 chip_code[4];	/* FTDI chip identification code */
133 	u8 reserved[8];
134 } __packed;
135 
136 struct ft260_get_system_status_report {
137 	u8 report;		/* FT260_SYSTEM_SETTINGS */
138 	u8 chip_mode;		/* DCNF0 and DCNF1 status, bits 0-1 */
139 	u8 clock_ctl;		/* 0 - 12MHz, 1 - 24MHz, 2 - 48MHz */
140 	u8 suspend_status;	/* 0 - not suspended, 1 - suspended */
141 	u8 pwren_status;	/* 0 - FT260 is not ready, 1 - ready */
142 	u8 i2c_enable;		/* 0 - disabled, 1 - enabled */
143 	u8 uart_mode;		/* 0 - OFF; 1 - RTS_CTS, 2 - DTR_DSR, */
144 				/* 3 - XON_XOFF, 4 - No flow control */
145 	u8 hid_over_i2c_en;	/* 0 - disabled, 1 - enabled */
146 	u8 gpio2_function;	/* 0 - GPIO,  1 - SUSPOUT, */
147 				/* 2 - PWREN, 4 - TX_LED */
148 	u8 gpioA_function;	/* 0 - GPIO, 3 - TX_ACTIVE, 4 - TX_LED */
149 	u8 gpioG_function;	/* 0 - GPIO, 2 - PWREN, */
150 				/* 5 - RX_LED, 6 - BCD_DET */
151 	u8 suspend_out_pol;	/* 0 - active-high, 1 - active-low */
152 	u8 enable_wakeup_int;	/* 0 - disabled, 1 - enabled */
153 	u8 intr_cond;		/* Interrupt trigger conditions */
154 	u8 power_saving_en;	/* 0 - disabled, 1 - enabled */
155 	u8 reserved[10];
156 } __packed;
157 
158 struct ft260_get_i2c_status_report {
159 	u8 report;		/* FT260_I2C_STATUS */
160 	u8 bus_status;		/* I2C bus status */
161 	__le16 clock;		/* I2C bus clock in range 60-3400 KHz */
162 	u8 reserved;
163 } __packed;
164 
165 /* Feature Out reports */
166 
167 struct ft260_set_system_clock_report {
168 	u8 report;		/* FT260_SYSTEM_SETTINGS */
169 	u8 request;		/* FT260_SET_CLOCK */
170 	u8 clock_ctl;		/* 0 - 12MHz, 1 - 24MHz, 2 - 48MHz */
171 } __packed;
172 
173 struct ft260_set_i2c_mode_report {
174 	u8 report;		/* FT260_SYSTEM_SETTINGS */
175 	u8 request;		/* FT260_SET_I2C_MODE */
176 	u8 i2c_enable;		/* 0 - disabled, 1 - enabled */
177 } __packed;
178 
179 struct ft260_set_uart_mode_report {
180 	u8 report;		/* FT260_SYSTEM_SETTINGS */
181 	u8 request;		/* FT260_SET_UART_MODE */
182 	u8 uart_mode;		/* 0 - OFF; 1 - RTS_CTS, 2 - DTR_DSR, */
183 				/* 3 - XON_XOFF, 4 - No flow control */
184 } __packed;
185 
186 struct ft260_set_i2c_reset_report {
187 	u8 report;		/* FT260_SYSTEM_SETTINGS */
188 	u8 request;		/* FT260_SET_I2C_RESET */
189 } __packed;
190 
191 struct ft260_set_i2c_speed_report {
192 	u8 report;		/* FT260_SYSTEM_SETTINGS */
193 	u8 request;		/* FT260_SET_I2C_CLOCK_SPEED */
194 	__le16 clock;		/* I2C bus clock in range 60-3400 KHz */
195 } __packed;
196 
197 /* Data transfer reports */
198 
199 struct ft260_i2c_write_request_report {
200 	u8 report;		/* FT260_I2C_REPORT */
201 	u8 address;		/* 7-bit I2C address */
202 	u8 flag;		/* I2C transaction condition */
203 	u8 length;		/* data payload length */
204 	u8 data[FT260_WR_DATA_MAX]; /* data payload */
205 } __packed;
206 
207 struct ft260_i2c_read_request_report {
208 	u8 report;		/* FT260_I2C_READ_REQ */
209 	u8 address;		/* 7-bit I2C address */
210 	u8 flag;		/* I2C transaction condition */
211 	__le16 length;		/* data payload length */
212 } __packed;
213 
214 struct ft260_i2c_input_report {
215 	u8 report;		/* FT260_I2C_REPORT */
216 	u8 length;		/* data payload length */
217 	u8 data[2];		/* data payload */
218 } __packed;
219 
220 static const struct hid_device_id ft260_devices[] = {
221 	{ HID_USB_DEVICE(USB_VENDOR_ID_FUTURE_TECHNOLOGY,
222 			 USB_DEVICE_ID_FT260) },
223 	{ /* END OF LIST */ }
224 };
225 MODULE_DEVICE_TABLE(hid, ft260_devices);
226 
227 struct ft260_device {
228 	struct i2c_adapter adap;
229 	struct hid_device *hdev;
230 	struct completion wait;
231 	struct mutex lock;
232 	u8 write_buf[FT260_REPORT_MAX_LENGTH];
233 	u8 *read_buf;
234 	u16 read_idx;
235 	u16 read_len;
236 	u16 clock;
237 };
238 
239 static int ft260_hid_feature_report_get(struct hid_device *hdev,
240 					unsigned char report_id, u8 *data,
241 					size_t len)
242 {
243 	u8 *buf;
244 	int ret;
245 
246 	buf = kmalloc(len, GFP_KERNEL);
247 	if (!buf)
248 		return -ENOMEM;
249 
250 	ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT,
251 				 HID_REQ_GET_REPORT);
252 	if (likely(ret == len))
253 		memcpy(data, buf, len);
254 	else if (ret >= 0)
255 		ret = -EIO;
256 	kfree(buf);
257 	return ret;
258 }
259 
260 static int ft260_hid_feature_report_set(struct hid_device *hdev, u8 *data,
261 					size_t len)
262 {
263 	u8 *buf;
264 	int ret;
265 
266 	buf = kmemdup(data, len, GFP_KERNEL);
267 	if (!buf)
268 		return -ENOMEM;
269 
270 	buf[0] = FT260_SYSTEM_SETTINGS;
271 
272 	ret = hid_hw_raw_request(hdev, buf[0], buf, len, HID_FEATURE_REPORT,
273 				 HID_REQ_SET_REPORT);
274 
275 	kfree(buf);
276 	return ret;
277 }
278 
279 static int ft260_i2c_reset(struct hid_device *hdev)
280 {
281 	struct ft260_set_i2c_reset_report report;
282 	int ret;
283 
284 	report.request = FT260_SET_I2C_RESET;
285 
286 	ret = ft260_hid_feature_report_set(hdev, (u8 *)&report, sizeof(report));
287 	if (ret < 0) {
288 		hid_err(hdev, "failed to reset I2C controller: %d\n", ret);
289 		return ret;
290 	}
291 
292 	ft260_dbg("done\n");
293 	return ret;
294 }
295 
296 static int ft260_xfer_status(struct ft260_device *dev)
297 {
298 	struct hid_device *hdev = dev->hdev;
299 	struct ft260_get_i2c_status_report report;
300 	int ret;
301 
302 	ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
303 					   (u8 *)&report, sizeof(report));
304 	if (unlikely(ret < 0)) {
305 		hid_err(hdev, "failed to retrieve status: %d\n", ret);
306 		return ret;
307 	}
308 
309 	dev->clock = le16_to_cpu(report.clock);
310 	ft260_dbg("bus_status %#02x, clock %u\n", report.bus_status,
311 		  dev->clock);
312 
313 	if (report.bus_status & FT260_I2C_STATUS_CTRL_BUSY)
314 		return -EAGAIN;
315 
316 	/*
317 	 * The error condition (bit 1) is a status bit reflecting any
318 	 * error conditions. When any of the bits 2, 3, or 4 are raised
319 	 * to 1, bit 1 is also set to 1.
320 	 */
321 	if (report.bus_status & FT260_I2C_STATUS_ERROR) {
322 		hid_err(hdev, "i2c bus error: %#02x\n", report.bus_status);
323 		return -EIO;
324 	}
325 
326 	return 0;
327 }
328 
329 static int ft260_hid_output_report(struct hid_device *hdev, u8 *data,
330 				   size_t len)
331 {
332 	u8 *buf;
333 	int ret;
334 
335 	buf = kmemdup(data, len, GFP_KERNEL);
336 	if (!buf)
337 		return -ENOMEM;
338 
339 	ret = hid_hw_output_report(hdev, buf, len);
340 
341 	kfree(buf);
342 	return ret;
343 }
344 
345 static int ft260_hid_output_report_check_status(struct ft260_device *dev,
346 						u8 *data, int len)
347 {
348 	int ret, usec, try = 3;
349 	struct hid_device *hdev = dev->hdev;
350 
351 	ret = ft260_hid_output_report(hdev, data, len);
352 	if (ret < 0) {
353 		hid_err(hdev, "%s: failed to start transfer, ret %d\n",
354 			__func__, ret);
355 		ft260_i2c_reset(hdev);
356 		return ret;
357 	}
358 
359 	/* transfer time = 1 / clock(KHz) * 10 bits * bytes */
360 	usec = 10000 / dev->clock * len;
361 	usleep_range(usec, usec + 100);
362 	ft260_dbg("wait %d usec, len %d\n", usec, len);
363 	do {
364 		ret = ft260_xfer_status(dev);
365 		if (ret != -EAGAIN)
366 			break;
367 	} while (--try);
368 
369 	if (ret == 0)
370 		return 0;
371 
372 	ft260_i2c_reset(hdev);
373 	return -EIO;
374 }
375 
376 static int ft260_i2c_write(struct ft260_device *dev, u8 addr, u8 *data,
377 			   int data_len, u8 flag)
378 {
379 	int len, ret, idx = 0;
380 	struct hid_device *hdev = dev->hdev;
381 	struct ft260_i2c_write_request_report *rep =
382 		(struct ft260_i2c_write_request_report *)dev->write_buf;
383 
384 	do {
385 		if (data_len <= FT260_WR_DATA_MAX)
386 			len = data_len;
387 		else
388 			len = FT260_WR_DATA_MAX;
389 
390 		rep->report = FT260_I2C_DATA_REPORT_ID(len);
391 		rep->address = addr;
392 		rep->length = len;
393 		rep->flag = flag;
394 
395 		memcpy(rep->data, &data[idx], len);
396 
397 		ft260_dbg("rep %#02x addr %#02x off %d len %d d[0] %#02x\n",
398 			  rep->report, addr, idx, len, data[0]);
399 
400 		ret = ft260_hid_output_report_check_status(dev, (u8 *)rep,
401 							   len + 4);
402 		if (ret < 0) {
403 			hid_err(hdev, "%s: failed to start transfer, ret %d\n",
404 				__func__, ret);
405 			return ret;
406 		}
407 
408 		data_len -= len;
409 		idx += len;
410 
411 	} while (data_len > 0);
412 
413 	return 0;
414 }
415 
416 static int ft260_smbus_write(struct ft260_device *dev, u8 addr, u8 cmd,
417 			     u8 *data, u8 data_len, u8 flag)
418 {
419 	int ret = 0;
420 	int len = 4;
421 
422 	struct ft260_i2c_write_request_report *rep =
423 		(struct ft260_i2c_write_request_report *)dev->write_buf;
424 
425 	if (data_len >= sizeof(rep->data))
426 		return -EINVAL;
427 
428 	rep->address = addr;
429 	rep->data[0] = cmd;
430 	rep->length = data_len + 1;
431 	rep->flag = flag;
432 	len += rep->length;
433 
434 	rep->report = FT260_I2C_DATA_REPORT_ID(len);
435 
436 	if (data_len > 0)
437 		memcpy(&rep->data[1], data, data_len);
438 
439 	ft260_dbg("rep %#02x addr %#02x cmd %#02x datlen %d replen %d\n",
440 		  rep->report, addr, cmd, rep->length, len);
441 
442 	ret = ft260_hid_output_report_check_status(dev, (u8 *)rep, len);
443 
444 	return ret;
445 }
446 
447 static int ft260_i2c_read(struct ft260_device *dev, u8 addr, u8 *data,
448 			  u16 len, u8 flag)
449 {
450 	struct ft260_i2c_read_request_report rep;
451 	struct hid_device *hdev = dev->hdev;
452 	int timeout;
453 	int ret;
454 
455 	if (len > FT260_RD_DATA_MAX) {
456 		hid_err(hdev, "%s: unsupported rd len: %d\n", __func__, len);
457 		return -EINVAL;
458 	}
459 
460 	dev->read_idx = 0;
461 	dev->read_buf = data;
462 	dev->read_len = len;
463 
464 	rep.report = FT260_I2C_READ_REQ;
465 	rep.length = cpu_to_le16(len);
466 	rep.address = addr;
467 	rep.flag = flag;
468 
469 	ft260_dbg("rep %#02x addr %#02x len %d\n", rep.report, rep.address,
470 		  rep.length);
471 
472 	reinit_completion(&dev->wait);
473 
474 	ret = ft260_hid_output_report(hdev, (u8 *)&rep, sizeof(rep));
475 	if (ret < 0) {
476 		hid_err(hdev, "%s: failed to start transaction, ret %d\n",
477 			__func__, ret);
478 		return ret;
479 	}
480 
481 	timeout = msecs_to_jiffies(5000);
482 	if (!wait_for_completion_timeout(&dev->wait, timeout)) {
483 		ft260_i2c_reset(hdev);
484 		return -ETIMEDOUT;
485 	}
486 
487 	ret = ft260_xfer_status(dev);
488 	if (ret == 0)
489 		return 0;
490 
491 	ft260_i2c_reset(hdev);
492 	return -EIO;
493 }
494 
495 /*
496  * A random read operation is implemented as a dummy write operation, followed
497  * by a current address read operation. The dummy write operation is used to
498  * load the target byte address into the current byte address counter, from
499  * which the subsequent current address read operation then reads.
500  */
501 static int ft260_i2c_write_read(struct ft260_device *dev, struct i2c_msg *msgs)
502 {
503 	int len, ret;
504 	u16 left_len = msgs[1].len;
505 	u8 *read_buf = msgs[1].buf;
506 	u8 addr = msgs[0].addr;
507 	u16 read_off = 0;
508 	struct hid_device *hdev = dev->hdev;
509 
510 	if (msgs[0].len > 2) {
511 		hid_err(hdev, "%s: unsupported wr len: %d\n", __func__,
512 			msgs[0].len);
513 		return -EOPNOTSUPP;
514 	}
515 
516 	memcpy(&read_off, msgs[0].buf, msgs[0].len);
517 
518 	do {
519 		if (left_len <= FT260_RD_DATA_MAX)
520 			len = left_len;
521 		else
522 			len = FT260_RD_DATA_MAX;
523 
524 		ft260_dbg("read_off %#x left_len %d len %d\n", read_off,
525 			  left_len, len);
526 
527 		ret = ft260_i2c_write(dev, addr, (u8 *)&read_off, msgs[0].len,
528 				      FT260_FLAG_START);
529 		if (ret < 0)
530 			return ret;
531 
532 		ret = ft260_i2c_read(dev, addr, read_buf, len,
533 				     FT260_FLAG_START_STOP);
534 		if (ret < 0)
535 			return ret;
536 
537 		left_len -= len;
538 		read_buf += len;
539 		read_off += len;
540 
541 	} while (left_len > 0);
542 
543 	return 0;
544 }
545 
546 static int ft260_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
547 			  int num)
548 {
549 	int ret;
550 	struct ft260_device *dev = i2c_get_adapdata(adapter);
551 	struct hid_device *hdev = dev->hdev;
552 
553 	mutex_lock(&dev->lock);
554 
555 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
556 	if (ret < 0) {
557 		hid_err(hdev, "failed to enter FULLON power mode: %d\n", ret);
558 		mutex_unlock(&dev->lock);
559 		return ret;
560 	}
561 
562 	if (num == 1) {
563 		if (msgs->flags & I2C_M_RD)
564 			ret = ft260_i2c_read(dev, msgs->addr, msgs->buf,
565 					     msgs->len, FT260_FLAG_START_STOP);
566 		else
567 			ret = ft260_i2c_write(dev, msgs->addr, msgs->buf,
568 					      msgs->len, FT260_FLAG_START_STOP);
569 		if (ret < 0)
570 			goto i2c_exit;
571 
572 	} else {
573 		/* Combined write then read message */
574 		ret = ft260_i2c_write_read(dev, msgs);
575 		if (ret < 0)
576 			goto i2c_exit;
577 	}
578 
579 	ret = num;
580 i2c_exit:
581 	hid_hw_power(hdev, PM_HINT_NORMAL);
582 	mutex_unlock(&dev->lock);
583 	return ret;
584 }
585 
586 static int ft260_smbus_xfer(struct i2c_adapter *adapter, u16 addr, u16 flags,
587 			    char read_write, u8 cmd, int size,
588 			    union i2c_smbus_data *data)
589 {
590 	int ret;
591 	struct ft260_device *dev = i2c_get_adapdata(adapter);
592 	struct hid_device *hdev = dev->hdev;
593 
594 	ft260_dbg("smbus size %d\n", size);
595 
596 	mutex_lock(&dev->lock);
597 
598 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
599 	if (ret < 0) {
600 		hid_err(hdev, "power management error: %d\n", ret);
601 		mutex_unlock(&dev->lock);
602 		return ret;
603 	}
604 
605 	switch (size) {
606 	case I2C_SMBUS_QUICK:
607 		if (read_write == I2C_SMBUS_READ)
608 			ret = ft260_i2c_read(dev, addr, &data->byte, 0,
609 					     FT260_FLAG_START_STOP);
610 		else
611 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
612 						FT260_FLAG_START_STOP);
613 		break;
614 	case I2C_SMBUS_BYTE:
615 		if (read_write == I2C_SMBUS_READ)
616 			ret = ft260_i2c_read(dev, addr, &data->byte, 1,
617 					     FT260_FLAG_START_STOP);
618 		else
619 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
620 						FT260_FLAG_START_STOP);
621 		break;
622 	case I2C_SMBUS_BYTE_DATA:
623 		if (read_write == I2C_SMBUS_READ) {
624 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
625 						FT260_FLAG_START);
626 			if (ret)
627 				goto smbus_exit;
628 
629 			ret = ft260_i2c_read(dev, addr, &data->byte, 1,
630 					     FT260_FLAG_START_STOP_REPEATED);
631 		} else {
632 			ret = ft260_smbus_write(dev, addr, cmd, &data->byte, 1,
633 						FT260_FLAG_START_STOP);
634 		}
635 		break;
636 	case I2C_SMBUS_WORD_DATA:
637 		if (read_write == I2C_SMBUS_READ) {
638 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
639 						FT260_FLAG_START);
640 			if (ret)
641 				goto smbus_exit;
642 
643 			ret = ft260_i2c_read(dev, addr, (u8 *)&data->word, 2,
644 					     FT260_FLAG_START_STOP_REPEATED);
645 		} else {
646 			ret = ft260_smbus_write(dev, addr, cmd,
647 						(u8 *)&data->word, 2,
648 						FT260_FLAG_START_STOP);
649 		}
650 		break;
651 	case I2C_SMBUS_BLOCK_DATA:
652 		if (read_write == I2C_SMBUS_READ) {
653 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
654 						FT260_FLAG_START);
655 			if (ret)
656 				goto smbus_exit;
657 
658 			ret = ft260_i2c_read(dev, addr, data->block,
659 					     data->block[0] + 1,
660 					     FT260_FLAG_START_STOP_REPEATED);
661 		} else {
662 			ret = ft260_smbus_write(dev, addr, cmd, data->block,
663 						data->block[0] + 1,
664 						FT260_FLAG_START_STOP);
665 		}
666 		break;
667 	case I2C_SMBUS_I2C_BLOCK_DATA:
668 		if (read_write == I2C_SMBUS_READ) {
669 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
670 						FT260_FLAG_START);
671 			if (ret)
672 				goto smbus_exit;
673 
674 			ret = ft260_i2c_read(dev, addr, data->block + 1,
675 					     data->block[0],
676 					     FT260_FLAG_START_STOP_REPEATED);
677 		} else {
678 			ret = ft260_smbus_write(dev, addr, cmd, data->block + 1,
679 						data->block[0],
680 						FT260_FLAG_START_STOP);
681 		}
682 		break;
683 	default:
684 		hid_err(hdev, "unsupported smbus transaction size %d\n", size);
685 		ret = -EOPNOTSUPP;
686 	}
687 
688 smbus_exit:
689 	hid_hw_power(hdev, PM_HINT_NORMAL);
690 	mutex_unlock(&dev->lock);
691 	return ret;
692 }
693 
694 static u32 ft260_functionality(struct i2c_adapter *adap)
695 {
696 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_QUICK |
697 	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
698 	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
699 }
700 
701 static const struct i2c_adapter_quirks ft260_i2c_quirks = {
702 	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
703 	.max_comb_1st_msg_len = 2,
704 };
705 
706 static const struct i2c_algorithm ft260_i2c_algo = {
707 	.master_xfer = ft260_i2c_xfer,
708 	.smbus_xfer = ft260_smbus_xfer,
709 	.functionality = ft260_functionality,
710 };
711 
712 static int ft260_get_system_config(struct hid_device *hdev,
713 				   struct ft260_get_system_status_report *cfg)
714 {
715 	int ret;
716 	int len = sizeof(struct ft260_get_system_status_report);
717 
718 	ret = ft260_hid_feature_report_get(hdev, FT260_SYSTEM_SETTINGS,
719 					   (u8 *)cfg, len);
720 	if (ret < 0) {
721 		hid_err(hdev, "failed to retrieve system status\n");
722 		return ret;
723 	}
724 	return 0;
725 }
726 
727 static int ft260_is_interface_enabled(struct hid_device *hdev)
728 {
729 	struct ft260_get_system_status_report cfg;
730 	struct usb_interface *usbif = to_usb_interface(hdev->dev.parent);
731 	int interface = usbif->cur_altsetting->desc.bInterfaceNumber;
732 	int ret;
733 
734 	ret = ft260_get_system_config(hdev, &cfg);
735 	if (ret < 0)
736 		return ret;
737 
738 	ft260_dbg("interface:  0x%02x\n", interface);
739 	ft260_dbg("chip mode:  0x%02x\n", cfg.chip_mode);
740 	ft260_dbg("clock_ctl:  0x%02x\n", cfg.clock_ctl);
741 	ft260_dbg("i2c_enable: 0x%02x\n", cfg.i2c_enable);
742 	ft260_dbg("uart_mode:  0x%02x\n", cfg.uart_mode);
743 
744 	switch (cfg.chip_mode) {
745 	case FT260_MODE_ALL:
746 	case FT260_MODE_BOTH:
747 		if (interface == 1)
748 			hid_info(hdev, "uart interface is not supported\n");
749 		else
750 			ret = 1;
751 		break;
752 	case FT260_MODE_UART:
753 		hid_info(hdev, "uart interface is not supported\n");
754 		break;
755 	case FT260_MODE_I2C:
756 		ret = 1;
757 		break;
758 	}
759 	return ret;
760 }
761 
762 static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len,
763 			   u8 *field, u8 *buf)
764 {
765 	int ret;
766 
767 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
768 	if (ret < 0)
769 		return ret;
770 
771 	return scnprintf(buf, PAGE_SIZE, "%d\n", *field);
772 }
773 
774 static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
775 			   u16 *field, u8 *buf)
776 {
777 	int ret;
778 
779 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
780 	if (ret < 0)
781 		return ret;
782 
783 	return scnprintf(buf, PAGE_SIZE, "%d\n", le16_to_cpu(*field));
784 }
785 
786 #define FT260_ATTR_SHOW(name, reptype, id, type, func)			       \
787 	static ssize_t name##_show(struct device *kdev,			       \
788 				   struct device_attribute *attr, char *buf)   \
789 	{								       \
790 		struct reptype rep;					       \
791 		struct hid_device *hdev = to_hid_device(kdev);		       \
792 		type *field = &rep.name;				       \
793 		int len = sizeof(rep);					       \
794 									       \
795 		return func(hdev, id, (u8 *)&rep, len, field, buf);	       \
796 	}
797 
798 #define FT260_SSTAT_ATTR_SHOW(name)					       \
799 		FT260_ATTR_SHOW(name, ft260_get_system_status_report,	       \
800 				FT260_SYSTEM_SETTINGS, u8, ft260_byte_show)
801 
802 #define FT260_I2CST_ATTR_SHOW(name)					       \
803 		FT260_ATTR_SHOW(name, ft260_get_i2c_status_report,	       \
804 				FT260_I2C_STATUS, u16, ft260_word_show)
805 
806 #define FT260_ATTR_STORE(name, reptype, id, req, type, func)		       \
807 	static ssize_t name##_store(struct device *kdev,		       \
808 				    struct device_attribute *attr,	       \
809 				    const char *buf, size_t count)	       \
810 	{								       \
811 		struct reptype rep;					       \
812 		struct hid_device *hdev = to_hid_device(kdev);		       \
813 		type name;						       \
814 		int ret;						       \
815 									       \
816 		if (!func(buf, 10, &name)) {				       \
817 			rep.name = name;				       \
818 			rep.report = id;				       \
819 			rep.request = req;				       \
820 			ret = ft260_hid_feature_report_set(hdev, (u8 *)&rep,   \
821 							   sizeof(rep));       \
822 			if (!ret)					       \
823 				ret = count;				       \
824 		} else {						       \
825 			ret = -EINVAL;					       \
826 		}							       \
827 		return ret;						       \
828 	}
829 
830 #define FT260_BYTE_ATTR_STORE(name, reptype, req)			       \
831 		FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req,    \
832 				 u8, kstrtou8)
833 
834 #define FT260_WORD_ATTR_STORE(name, reptype, req)			       \
835 		FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req,    \
836 				 u16, kstrtou16)
837 
838 FT260_SSTAT_ATTR_SHOW(chip_mode);
839 static DEVICE_ATTR_RO(chip_mode);
840 
841 FT260_SSTAT_ATTR_SHOW(pwren_status);
842 static DEVICE_ATTR_RO(pwren_status);
843 
844 FT260_SSTAT_ATTR_SHOW(suspend_status);
845 static DEVICE_ATTR_RO(suspend_status);
846 
847 FT260_SSTAT_ATTR_SHOW(hid_over_i2c_en);
848 static DEVICE_ATTR_RO(hid_over_i2c_en);
849 
850 FT260_SSTAT_ATTR_SHOW(power_saving_en);
851 static DEVICE_ATTR_RO(power_saving_en);
852 
853 FT260_SSTAT_ATTR_SHOW(i2c_enable);
854 FT260_BYTE_ATTR_STORE(i2c_enable, ft260_set_i2c_mode_report,
855 		      FT260_SET_I2C_MODE);
856 static DEVICE_ATTR_RW(i2c_enable);
857 
858 FT260_SSTAT_ATTR_SHOW(uart_mode);
859 FT260_BYTE_ATTR_STORE(uart_mode, ft260_set_uart_mode_report,
860 		      FT260_SET_UART_MODE);
861 static DEVICE_ATTR_RW(uart_mode);
862 
863 FT260_SSTAT_ATTR_SHOW(clock_ctl);
864 FT260_BYTE_ATTR_STORE(clock_ctl, ft260_set_system_clock_report,
865 		      FT260_SET_CLOCK);
866 static DEVICE_ATTR_RW(clock_ctl);
867 
868 FT260_I2CST_ATTR_SHOW(clock);
869 FT260_WORD_ATTR_STORE(clock, ft260_set_i2c_speed_report,
870 		      FT260_SET_I2C_CLOCK_SPEED);
871 static DEVICE_ATTR_RW(clock);
872 
873 static ssize_t i2c_reset_store(struct device *kdev,
874 			       struct device_attribute *attr, const char *buf,
875 			       size_t count)
876 {
877 	struct hid_device *hdev = to_hid_device(kdev);
878 	int ret = ft260_i2c_reset(hdev);
879 
880 	if (ret)
881 		return ret;
882 	return count;
883 }
884 static DEVICE_ATTR_WO(i2c_reset);
885 
886 static const struct attribute_group ft260_attr_group = {
887 	.attrs = (struct attribute *[]) {
888 		  &dev_attr_chip_mode.attr,
889 		  &dev_attr_pwren_status.attr,
890 		  &dev_attr_suspend_status.attr,
891 		  &dev_attr_hid_over_i2c_en.attr,
892 		  &dev_attr_power_saving_en.attr,
893 		  &dev_attr_i2c_enable.attr,
894 		  &dev_attr_uart_mode.attr,
895 		  &dev_attr_clock_ctl.attr,
896 		  &dev_attr_i2c_reset.attr,
897 		  &dev_attr_clock.attr,
898 		  NULL
899 	}
900 };
901 
902 static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
903 {
904 	struct ft260_device *dev;
905 	struct ft260_get_chip_version_report version;
906 	int ret;
907 
908 	if (!hid_is_usb(hdev))
909 		return -EINVAL;
910 
911 	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
912 	if (!dev)
913 		return -ENOMEM;
914 
915 	ret = hid_parse(hdev);
916 	if (ret) {
917 		hid_err(hdev, "failed to parse HID\n");
918 		return ret;
919 	}
920 
921 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
922 	if (ret) {
923 		hid_err(hdev, "failed to start HID HW\n");
924 		return ret;
925 	}
926 
927 	ret = hid_hw_open(hdev);
928 	if (ret) {
929 		hid_err(hdev, "failed to open HID HW\n");
930 		goto err_hid_stop;
931 	}
932 
933 	ret = ft260_hid_feature_report_get(hdev, FT260_CHIP_VERSION,
934 					   (u8 *)&version, sizeof(version));
935 	if (ret < 0) {
936 		hid_err(hdev, "failed to retrieve chip version\n");
937 		goto err_hid_close;
938 	}
939 
940 	hid_info(hdev, "chip code: %02x%02x %02x%02x\n",
941 		 version.chip_code[0], version.chip_code[1],
942 		 version.chip_code[2], version.chip_code[3]);
943 
944 	ret = ft260_is_interface_enabled(hdev);
945 	if (ret <= 0)
946 		goto err_hid_close;
947 
948 	hid_set_drvdata(hdev, dev);
949 	dev->hdev = hdev;
950 	dev->adap.owner = THIS_MODULE;
951 	dev->adap.class = I2C_CLASS_HWMON;
952 	dev->adap.algo = &ft260_i2c_algo;
953 	dev->adap.quirks = &ft260_i2c_quirks;
954 	dev->adap.dev.parent = &hdev->dev;
955 	snprintf(dev->adap.name, sizeof(dev->adap.name),
956 		 "FT260 usb-i2c bridge on hidraw%d",
957 		 ((struct hidraw *)hdev->hidraw)->minor);
958 
959 	mutex_init(&dev->lock);
960 	init_completion(&dev->wait);
961 
962 	ret = ft260_xfer_status(dev);
963 	if (ret)
964 		ft260_i2c_reset(hdev);
965 
966 	i2c_set_adapdata(&dev->adap, dev);
967 	ret = i2c_add_adapter(&dev->adap);
968 	if (ret) {
969 		hid_err(hdev, "failed to add i2c adapter\n");
970 		goto err_hid_close;
971 	}
972 
973 	ret = sysfs_create_group(&hdev->dev.kobj, &ft260_attr_group);
974 	if (ret < 0) {
975 		hid_err(hdev, "failed to create sysfs attrs\n");
976 		goto err_i2c_free;
977 	}
978 
979 	return 0;
980 
981 err_i2c_free:
982 	i2c_del_adapter(&dev->adap);
983 err_hid_close:
984 	hid_hw_close(hdev);
985 err_hid_stop:
986 	hid_hw_stop(hdev);
987 	return ret;
988 }
989 
990 static void ft260_remove(struct hid_device *hdev)
991 {
992 	struct ft260_device *dev = hid_get_drvdata(hdev);
993 
994 	if (!dev)
995 		return;
996 
997 	sysfs_remove_group(&hdev->dev.kobj, &ft260_attr_group);
998 	i2c_del_adapter(&dev->adap);
999 
1000 	hid_hw_close(hdev);
1001 	hid_hw_stop(hdev);
1002 }
1003 
1004 static int ft260_raw_event(struct hid_device *hdev, struct hid_report *report,
1005 			   u8 *data, int size)
1006 {
1007 	struct ft260_device *dev = hid_get_drvdata(hdev);
1008 	struct ft260_i2c_input_report *xfer = (void *)data;
1009 
1010 	if (xfer->report >= FT260_I2C_REPORT_MIN &&
1011 	    xfer->report <= FT260_I2C_REPORT_MAX) {
1012 		ft260_dbg("i2c resp: rep %#02x len %d\n", xfer->report,
1013 			  xfer->length);
1014 
1015 		memcpy(&dev->read_buf[dev->read_idx], &xfer->data,
1016 		       xfer->length);
1017 		dev->read_idx += xfer->length;
1018 
1019 		if (dev->read_idx == dev->read_len)
1020 			complete(&dev->wait);
1021 
1022 	} else {
1023 		hid_err(hdev, "unknown report: %#02x\n", xfer->report);
1024 		return 0;
1025 	}
1026 	return 1;
1027 }
1028 
1029 static struct hid_driver ft260_driver = {
1030 	.name		= "ft260",
1031 	.id_table	= ft260_devices,
1032 	.probe		= ft260_probe,
1033 	.remove		= ft260_remove,
1034 	.raw_event	= ft260_raw_event,
1035 };
1036 
1037 module_hid_driver(ft260_driver);
1038 MODULE_DESCRIPTION("FTDI FT260 USB HID to I2C host bridge");
1039 MODULE_AUTHOR("Michael Zaidman <michael.zaidman@gmail.com>");
1040 MODULE_LICENSE("GPL v2");
1041