xref: /openbmc/linux/drivers/hid/hid-ft260.c (revision 7a010c3c)
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 	if (report.bus_status & FT260_I2C_STATUS_BUS_BUSY)
317 		return -EBUSY;
318 
319 	if (report.bus_status & FT260_I2C_STATUS_ERROR)
320 		return -EIO;
321 
322 	ret = -EIO;
323 
324 	if (report.bus_status & FT260_I2C_STATUS_ADDR_NO_ACK)
325 		ft260_dbg("unacknowledged address\n");
326 
327 	if (report.bus_status & FT260_I2C_STATUS_DATA_NO_ACK)
328 		ft260_dbg("unacknowledged data\n");
329 
330 	if (report.bus_status & FT260_I2C_STATUS_ARBITR_LOST)
331 		ft260_dbg("arbitration loss\n");
332 
333 	if (report.bus_status & FT260_I2C_STATUS_CTRL_IDLE)
334 		ret = 0;
335 
336 	return ret;
337 }
338 
339 static int ft260_hid_output_report(struct hid_device *hdev, u8 *data,
340 				   size_t len)
341 {
342 	u8 *buf;
343 	int ret;
344 
345 	buf = kmemdup(data, len, GFP_KERNEL);
346 	if (!buf)
347 		return -ENOMEM;
348 
349 	ret = hid_hw_output_report(hdev, buf, len);
350 
351 	kfree(buf);
352 	return ret;
353 }
354 
355 static int ft260_hid_output_report_check_status(struct ft260_device *dev,
356 						u8 *data, int len)
357 {
358 	int ret, usec, try = 3;
359 	struct hid_device *hdev = dev->hdev;
360 
361 	ret = ft260_hid_output_report(hdev, data, len);
362 	if (ret < 0) {
363 		hid_err(hdev, "%s: failed to start transfer, ret %d\n",
364 			__func__, ret);
365 		ft260_i2c_reset(hdev);
366 		return ret;
367 	}
368 
369 	/* transfer time = 1 / clock(KHz) * 10 bits * bytes */
370 	usec = 10000 / dev->clock * len;
371 	usleep_range(usec, usec + 100);
372 	ft260_dbg("wait %d usec, len %d\n", usec, len);
373 	do {
374 		ret = ft260_xfer_status(dev);
375 		if (ret != -EAGAIN)
376 			break;
377 	} while (--try);
378 
379 	if (ret == 0 || ret == -EBUSY)
380 		return 0;
381 
382 	ft260_i2c_reset(hdev);
383 	return -EIO;
384 }
385 
386 static int ft260_i2c_write(struct ft260_device *dev, u8 addr, u8 *data,
387 			   int data_len, u8 flag)
388 {
389 	int len, ret, idx = 0;
390 	struct hid_device *hdev = dev->hdev;
391 	struct ft260_i2c_write_request_report *rep =
392 		(struct ft260_i2c_write_request_report *)dev->write_buf;
393 
394 	do {
395 		if (data_len <= FT260_WR_DATA_MAX)
396 			len = data_len;
397 		else
398 			len = FT260_WR_DATA_MAX;
399 
400 		rep->report = FT260_I2C_DATA_REPORT_ID(len);
401 		rep->address = addr;
402 		rep->length = len;
403 		rep->flag = flag;
404 
405 		memcpy(rep->data, &data[idx], len);
406 
407 		ft260_dbg("rep %#02x addr %#02x off %d len %d d[0] %#02x\n",
408 			  rep->report, addr, idx, len, data[0]);
409 
410 		ret = ft260_hid_output_report_check_status(dev, (u8 *)rep,
411 							   len + 4);
412 		if (ret < 0) {
413 			hid_err(hdev, "%s: failed to start transfer, ret %d\n",
414 				__func__, ret);
415 			return ret;
416 		}
417 
418 		data_len -= len;
419 		idx += len;
420 
421 	} while (data_len > 0);
422 
423 	return 0;
424 }
425 
426 static int ft260_smbus_write(struct ft260_device *dev, u8 addr, u8 cmd,
427 			     u8 *data, u8 data_len, u8 flag)
428 {
429 	int ret = 0;
430 	int len = 4;
431 
432 	struct ft260_i2c_write_request_report *rep =
433 		(struct ft260_i2c_write_request_report *)dev->write_buf;
434 
435 	if (data_len >= sizeof(rep->data))
436 		return -EINVAL;
437 
438 	rep->address = addr;
439 	rep->data[0] = cmd;
440 	rep->length = data_len + 1;
441 	rep->flag = flag;
442 	len += rep->length;
443 
444 	rep->report = FT260_I2C_DATA_REPORT_ID(len);
445 
446 	if (data_len > 0)
447 		memcpy(&rep->data[1], data, data_len);
448 
449 	ft260_dbg("rep %#02x addr %#02x cmd %#02x datlen %d replen %d\n",
450 		  rep->report, addr, cmd, rep->length, len);
451 
452 	ret = ft260_hid_output_report_check_status(dev, (u8 *)rep, len);
453 
454 	return ret;
455 }
456 
457 static int ft260_i2c_read(struct ft260_device *dev, u8 addr, u8 *data,
458 			  u16 len, u8 flag)
459 {
460 	struct ft260_i2c_read_request_report rep;
461 	struct hid_device *hdev = dev->hdev;
462 	int timeout;
463 	int ret;
464 
465 	if (len > FT260_RD_DATA_MAX) {
466 		hid_err(hdev, "%s: unsupported rd len: %d\n", __func__, len);
467 		return -EINVAL;
468 	}
469 
470 	dev->read_idx = 0;
471 	dev->read_buf = data;
472 	dev->read_len = len;
473 
474 	rep.report = FT260_I2C_READ_REQ;
475 	rep.length = cpu_to_le16(len);
476 	rep.address = addr;
477 	rep.flag = flag;
478 
479 	ft260_dbg("rep %#02x addr %#02x len %d\n", rep.report, rep.address,
480 		  rep.length);
481 
482 	reinit_completion(&dev->wait);
483 
484 	ret = ft260_hid_output_report(hdev, (u8 *)&rep, sizeof(rep));
485 	if (ret < 0) {
486 		hid_err(hdev, "%s: failed to start transaction, ret %d\n",
487 			__func__, ret);
488 		return ret;
489 	}
490 
491 	timeout = msecs_to_jiffies(5000);
492 	if (!wait_for_completion_timeout(&dev->wait, timeout)) {
493 		ft260_i2c_reset(hdev);
494 		return -ETIMEDOUT;
495 	}
496 
497 	ret = ft260_xfer_status(dev);
498 	if (ret == 0)
499 		return 0;
500 
501 	ft260_i2c_reset(hdev);
502 	return -EIO;
503 }
504 
505 /*
506  * A random read operation is implemented as a dummy write operation, followed
507  * by a current address read operation. The dummy write operation is used to
508  * load the target byte address into the current byte address counter, from
509  * which the subsequent current address read operation then reads.
510  */
511 static int ft260_i2c_write_read(struct ft260_device *dev, struct i2c_msg *msgs)
512 {
513 	int len, ret;
514 	u16 left_len = msgs[1].len;
515 	u8 *read_buf = msgs[1].buf;
516 	u8 addr = msgs[0].addr;
517 	u16 read_off = 0;
518 	struct hid_device *hdev = dev->hdev;
519 
520 	if (msgs[0].len > 2) {
521 		hid_err(hdev, "%s: unsupported wr len: %d\n", __func__,
522 			msgs[0].len);
523 		return -EOPNOTSUPP;
524 	}
525 
526 	memcpy(&read_off, msgs[0].buf, msgs[0].len);
527 
528 	do {
529 		if (left_len <= FT260_RD_DATA_MAX)
530 			len = left_len;
531 		else
532 			len = FT260_RD_DATA_MAX;
533 
534 		ft260_dbg("read_off %#x left_len %d len %d\n", read_off,
535 			  left_len, len);
536 
537 		ret = ft260_i2c_write(dev, addr, (u8 *)&read_off, msgs[0].len,
538 				      FT260_FLAG_START);
539 		if (ret < 0)
540 			return ret;
541 
542 		ret = ft260_i2c_read(dev, addr, read_buf, len,
543 				     FT260_FLAG_START_STOP);
544 		if (ret < 0)
545 			return ret;
546 
547 		left_len -= len;
548 		read_buf += len;
549 		read_off += len;
550 
551 	} while (left_len > 0);
552 
553 	return 0;
554 }
555 
556 static int ft260_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
557 			  int num)
558 {
559 	int ret;
560 	struct ft260_device *dev = i2c_get_adapdata(adapter);
561 	struct hid_device *hdev = dev->hdev;
562 
563 	mutex_lock(&dev->lock);
564 
565 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
566 	if (ret < 0) {
567 		hid_err(hdev, "failed to enter FULLON power mode: %d\n", ret);
568 		mutex_unlock(&dev->lock);
569 		return ret;
570 	}
571 
572 	if (num == 1) {
573 		if (msgs->flags & I2C_M_RD)
574 			ret = ft260_i2c_read(dev, msgs->addr, msgs->buf,
575 					     msgs->len, FT260_FLAG_START_STOP);
576 		else
577 			ret = ft260_i2c_write(dev, msgs->addr, msgs->buf,
578 					      msgs->len, FT260_FLAG_START_STOP);
579 		if (ret < 0)
580 			goto i2c_exit;
581 
582 	} else {
583 		/* Combined write then read message */
584 		ret = ft260_i2c_write_read(dev, msgs);
585 		if (ret < 0)
586 			goto i2c_exit;
587 	}
588 
589 	ret = num;
590 i2c_exit:
591 	hid_hw_power(hdev, PM_HINT_NORMAL);
592 	mutex_unlock(&dev->lock);
593 	return ret;
594 }
595 
596 static int ft260_smbus_xfer(struct i2c_adapter *adapter, u16 addr, u16 flags,
597 			    char read_write, u8 cmd, int size,
598 			    union i2c_smbus_data *data)
599 {
600 	int ret;
601 	struct ft260_device *dev = i2c_get_adapdata(adapter);
602 	struct hid_device *hdev = dev->hdev;
603 
604 	ft260_dbg("smbus size %d\n", size);
605 
606 	mutex_lock(&dev->lock);
607 
608 	ret = hid_hw_power(hdev, PM_HINT_FULLON);
609 	if (ret < 0) {
610 		hid_err(hdev, "power management error: %d\n", ret);
611 		mutex_unlock(&dev->lock);
612 		return ret;
613 	}
614 
615 	switch (size) {
616 	case I2C_SMBUS_QUICK:
617 		if (read_write == I2C_SMBUS_READ)
618 			ret = ft260_i2c_read(dev, addr, &data->byte, 0,
619 					     FT260_FLAG_START_STOP);
620 		else
621 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
622 						FT260_FLAG_START_STOP);
623 		break;
624 	case I2C_SMBUS_BYTE:
625 		if (read_write == I2C_SMBUS_READ)
626 			ret = ft260_i2c_read(dev, addr, &data->byte, 1,
627 					     FT260_FLAG_START_STOP);
628 		else
629 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
630 						FT260_FLAG_START_STOP);
631 		break;
632 	case I2C_SMBUS_BYTE_DATA:
633 		if (read_write == I2C_SMBUS_READ) {
634 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
635 						FT260_FLAG_START);
636 			if (ret)
637 				goto smbus_exit;
638 
639 			ret = ft260_i2c_read(dev, addr, &data->byte, 1,
640 					     FT260_FLAG_START_STOP_REPEATED);
641 		} else {
642 			ret = ft260_smbus_write(dev, addr, cmd, &data->byte, 1,
643 						FT260_FLAG_START_STOP);
644 		}
645 		break;
646 	case I2C_SMBUS_WORD_DATA:
647 		if (read_write == I2C_SMBUS_READ) {
648 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
649 						FT260_FLAG_START);
650 			if (ret)
651 				goto smbus_exit;
652 
653 			ret = ft260_i2c_read(dev, addr, (u8 *)&data->word, 2,
654 					     FT260_FLAG_START_STOP_REPEATED);
655 		} else {
656 			ret = ft260_smbus_write(dev, addr, cmd,
657 						(u8 *)&data->word, 2,
658 						FT260_FLAG_START_STOP);
659 		}
660 		break;
661 	case I2C_SMBUS_BLOCK_DATA:
662 		if (read_write == I2C_SMBUS_READ) {
663 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
664 						FT260_FLAG_START);
665 			if (ret)
666 				goto smbus_exit;
667 
668 			ret = ft260_i2c_read(dev, addr, data->block,
669 					     data->block[0] + 1,
670 					     FT260_FLAG_START_STOP_REPEATED);
671 		} else {
672 			ret = ft260_smbus_write(dev, addr, cmd, data->block,
673 						data->block[0] + 1,
674 						FT260_FLAG_START_STOP);
675 		}
676 		break;
677 	case I2C_SMBUS_I2C_BLOCK_DATA:
678 		if (read_write == I2C_SMBUS_READ) {
679 			ret = ft260_smbus_write(dev, addr, cmd, NULL, 0,
680 						FT260_FLAG_START);
681 			if (ret)
682 				goto smbus_exit;
683 
684 			ret = ft260_i2c_read(dev, addr, data->block + 1,
685 					     data->block[0],
686 					     FT260_FLAG_START_STOP_REPEATED);
687 		} else {
688 			ret = ft260_smbus_write(dev, addr, cmd, data->block + 1,
689 						data->block[0],
690 						FT260_FLAG_START_STOP);
691 		}
692 		break;
693 	default:
694 		hid_err(hdev, "unsupported smbus transaction size %d\n", size);
695 		ret = -EOPNOTSUPP;
696 	}
697 
698 smbus_exit:
699 	hid_hw_power(hdev, PM_HINT_NORMAL);
700 	mutex_unlock(&dev->lock);
701 	return ret;
702 }
703 
704 static u32 ft260_functionality(struct i2c_adapter *adap)
705 {
706 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_QUICK |
707 	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
708 	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
709 }
710 
711 static const struct i2c_adapter_quirks ft260_i2c_quirks = {
712 	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
713 	.max_comb_1st_msg_len = 2,
714 };
715 
716 static const struct i2c_algorithm ft260_i2c_algo = {
717 	.master_xfer = ft260_i2c_xfer,
718 	.smbus_xfer = ft260_smbus_xfer,
719 	.functionality = ft260_functionality,
720 };
721 
722 static int ft260_get_system_config(struct hid_device *hdev,
723 				   struct ft260_get_system_status_report *cfg)
724 {
725 	int ret;
726 	int len = sizeof(struct ft260_get_system_status_report);
727 
728 	ret = ft260_hid_feature_report_get(hdev, FT260_SYSTEM_SETTINGS,
729 					   (u8 *)cfg, len);
730 	if (ret < 0) {
731 		hid_err(hdev, "failed to retrieve system status\n");
732 		return ret;
733 	}
734 	return 0;
735 }
736 
737 static int ft260_is_interface_enabled(struct hid_device *hdev)
738 {
739 	struct ft260_get_system_status_report cfg;
740 	struct usb_interface *usbif = to_usb_interface(hdev->dev.parent);
741 	int interface = usbif->cur_altsetting->desc.bInterfaceNumber;
742 	int ret;
743 
744 	ret = ft260_get_system_config(hdev, &cfg);
745 	if (ret < 0)
746 		return ret;
747 
748 	ft260_dbg("interface:  0x%02x\n", interface);
749 	ft260_dbg("chip mode:  0x%02x\n", cfg.chip_mode);
750 	ft260_dbg("clock_ctl:  0x%02x\n", cfg.clock_ctl);
751 	ft260_dbg("i2c_enable: 0x%02x\n", cfg.i2c_enable);
752 	ft260_dbg("uart_mode:  0x%02x\n", cfg.uart_mode);
753 
754 	switch (cfg.chip_mode) {
755 	case FT260_MODE_ALL:
756 	case FT260_MODE_BOTH:
757 		if (interface == 1)
758 			hid_info(hdev, "uart interface is not supported\n");
759 		else
760 			ret = 1;
761 		break;
762 	case FT260_MODE_UART:
763 		hid_info(hdev, "uart interface is not supported\n");
764 		break;
765 	case FT260_MODE_I2C:
766 		ret = 1;
767 		break;
768 	}
769 	return ret;
770 }
771 
772 static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len,
773 			   u8 *field, u8 *buf)
774 {
775 	int ret;
776 
777 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
778 	if (ret < 0)
779 		return ret;
780 
781 	return scnprintf(buf, PAGE_SIZE, "%d\n", *field);
782 }
783 
784 static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
785 			   u16 *field, u8 *buf)
786 {
787 	int ret;
788 
789 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
790 	if (ret < 0)
791 		return ret;
792 
793 	return scnprintf(buf, PAGE_SIZE, "%d\n", le16_to_cpu(*field));
794 }
795 
796 #define FT260_ATTR_SHOW(name, reptype, id, type, func)			       \
797 	static ssize_t name##_show(struct device *kdev,			       \
798 				   struct device_attribute *attr, char *buf)   \
799 	{								       \
800 		struct reptype rep;					       \
801 		struct hid_device *hdev = to_hid_device(kdev);		       \
802 		type *field = &rep.name;				       \
803 		int len = sizeof(rep);					       \
804 									       \
805 		return func(hdev, id, (u8 *)&rep, len, field, buf);	       \
806 	}
807 
808 #define FT260_SSTAT_ATTR_SHOW(name)					       \
809 		FT260_ATTR_SHOW(name, ft260_get_system_status_report,	       \
810 				FT260_SYSTEM_SETTINGS, u8, ft260_byte_show)
811 
812 #define FT260_I2CST_ATTR_SHOW(name)					       \
813 		FT260_ATTR_SHOW(name, ft260_get_i2c_status_report,	       \
814 				FT260_I2C_STATUS, u16, ft260_word_show)
815 
816 #define FT260_ATTR_STORE(name, reptype, id, req, type, func)		       \
817 	static ssize_t name##_store(struct device *kdev,		       \
818 				    struct device_attribute *attr,	       \
819 				    const char *buf, size_t count)	       \
820 	{								       \
821 		struct reptype rep;					       \
822 		struct hid_device *hdev = to_hid_device(kdev);		       \
823 		type name;						       \
824 		int ret;						       \
825 									       \
826 		if (!func(buf, 10, &name)) {				       \
827 			rep.name = name;				       \
828 			rep.report = id;				       \
829 			rep.request = req;				       \
830 			ret = ft260_hid_feature_report_set(hdev, (u8 *)&rep,   \
831 							   sizeof(rep));       \
832 			if (!ret)					       \
833 				ret = count;				       \
834 		} else {						       \
835 			ret = -EINVAL;					       \
836 		}							       \
837 		return ret;						       \
838 	}
839 
840 #define FT260_BYTE_ATTR_STORE(name, reptype, req)			       \
841 		FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req,    \
842 				 u8, kstrtou8)
843 
844 #define FT260_WORD_ATTR_STORE(name, reptype, req)			       \
845 		FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req,    \
846 				 u16, kstrtou16)
847 
848 FT260_SSTAT_ATTR_SHOW(chip_mode);
849 static DEVICE_ATTR_RO(chip_mode);
850 
851 FT260_SSTAT_ATTR_SHOW(pwren_status);
852 static DEVICE_ATTR_RO(pwren_status);
853 
854 FT260_SSTAT_ATTR_SHOW(suspend_status);
855 static DEVICE_ATTR_RO(suspend_status);
856 
857 FT260_SSTAT_ATTR_SHOW(hid_over_i2c_en);
858 static DEVICE_ATTR_RO(hid_over_i2c_en);
859 
860 FT260_SSTAT_ATTR_SHOW(power_saving_en);
861 static DEVICE_ATTR_RO(power_saving_en);
862 
863 FT260_SSTAT_ATTR_SHOW(i2c_enable);
864 FT260_BYTE_ATTR_STORE(i2c_enable, ft260_set_i2c_mode_report,
865 		      FT260_SET_I2C_MODE);
866 static DEVICE_ATTR_RW(i2c_enable);
867 
868 FT260_SSTAT_ATTR_SHOW(uart_mode);
869 FT260_BYTE_ATTR_STORE(uart_mode, ft260_set_uart_mode_report,
870 		      FT260_SET_UART_MODE);
871 static DEVICE_ATTR_RW(uart_mode);
872 
873 FT260_SSTAT_ATTR_SHOW(clock_ctl);
874 FT260_BYTE_ATTR_STORE(clock_ctl, ft260_set_system_clock_report,
875 		      FT260_SET_CLOCK);
876 static DEVICE_ATTR_RW(clock_ctl);
877 
878 FT260_I2CST_ATTR_SHOW(clock);
879 FT260_WORD_ATTR_STORE(clock, ft260_set_i2c_speed_report,
880 		      FT260_SET_I2C_CLOCK_SPEED);
881 static DEVICE_ATTR_RW(clock);
882 
883 static ssize_t i2c_reset_store(struct device *kdev,
884 			       struct device_attribute *attr, const char *buf,
885 			       size_t count)
886 {
887 	struct hid_device *hdev = to_hid_device(kdev);
888 	int ret = ft260_i2c_reset(hdev);
889 
890 	if (ret)
891 		return ret;
892 	return count;
893 }
894 static DEVICE_ATTR_WO(i2c_reset);
895 
896 static const struct attribute_group ft260_attr_group = {
897 	.attrs = (struct attribute *[]) {
898 		  &dev_attr_chip_mode.attr,
899 		  &dev_attr_pwren_status.attr,
900 		  &dev_attr_suspend_status.attr,
901 		  &dev_attr_hid_over_i2c_en.attr,
902 		  &dev_attr_power_saving_en.attr,
903 		  &dev_attr_i2c_enable.attr,
904 		  &dev_attr_uart_mode.attr,
905 		  &dev_attr_clock_ctl.attr,
906 		  &dev_attr_i2c_reset.attr,
907 		  &dev_attr_clock.attr,
908 		  NULL
909 	}
910 };
911 
912 static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
913 {
914 	struct ft260_device *dev;
915 	struct ft260_get_chip_version_report version;
916 	int ret;
917 
918 	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
919 	if (!dev)
920 		return -ENOMEM;
921 
922 	ret = hid_parse(hdev);
923 	if (ret) {
924 		hid_err(hdev, "failed to parse HID\n");
925 		return ret;
926 	}
927 
928 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
929 	if (ret) {
930 		hid_err(hdev, "failed to start HID HW\n");
931 		return ret;
932 	}
933 
934 	ret = hid_hw_open(hdev);
935 	if (ret) {
936 		hid_err(hdev, "failed to open HID HW\n");
937 		goto err_hid_stop;
938 	}
939 
940 	ret = ft260_hid_feature_report_get(hdev, FT260_CHIP_VERSION,
941 					   (u8 *)&version, sizeof(version));
942 	if (ret < 0) {
943 		hid_err(hdev, "failed to retrieve chip version\n");
944 		goto err_hid_close;
945 	}
946 
947 	hid_info(hdev, "chip code: %02x%02x %02x%02x\n",
948 		 version.chip_code[0], version.chip_code[1],
949 		 version.chip_code[2], version.chip_code[3]);
950 
951 	ret = ft260_is_interface_enabled(hdev);
952 	if (ret <= 0)
953 		goto err_hid_close;
954 
955 	hid_set_drvdata(hdev, dev);
956 	dev->hdev = hdev;
957 	dev->adap.owner = THIS_MODULE;
958 	dev->adap.class = I2C_CLASS_HWMON;
959 	dev->adap.algo = &ft260_i2c_algo;
960 	dev->adap.quirks = &ft260_i2c_quirks;
961 	dev->adap.dev.parent = &hdev->dev;
962 	snprintf(dev->adap.name, sizeof(dev->adap.name),
963 		 "FT260 usb-i2c bridge on hidraw%d",
964 		 ((struct hidraw *)hdev->hidraw)->minor);
965 
966 	mutex_init(&dev->lock);
967 	init_completion(&dev->wait);
968 
969 	ret = i2c_add_adapter(&dev->adap);
970 	if (ret) {
971 		hid_err(hdev, "failed to add i2c adapter\n");
972 		goto err_hid_close;
973 	}
974 
975 	i2c_set_adapdata(&dev->adap, dev);
976 
977 	ret = sysfs_create_group(&hdev->dev.kobj, &ft260_attr_group);
978 	if (ret < 0) {
979 		hid_err(hdev, "failed to create sysfs attrs\n");
980 		goto err_i2c_free;
981 	}
982 
983 	ret = ft260_xfer_status(dev);
984 	if (ret)
985 		ft260_i2c_reset(hdev);
986 
987 	return 0;
988 
989 err_i2c_free:
990 	i2c_del_adapter(&dev->adap);
991 err_hid_close:
992 	hid_hw_close(hdev);
993 err_hid_stop:
994 	hid_hw_stop(hdev);
995 	return ret;
996 }
997 
998 static void ft260_remove(struct hid_device *hdev)
999 {
1000 	struct ft260_device *dev = hid_get_drvdata(hdev);
1001 
1002 	if (!dev)
1003 		return;
1004 
1005 	sysfs_remove_group(&hdev->dev.kobj, &ft260_attr_group);
1006 	i2c_del_adapter(&dev->adap);
1007 
1008 	hid_hw_close(hdev);
1009 	hid_hw_stop(hdev);
1010 }
1011 
1012 static int ft260_raw_event(struct hid_device *hdev, struct hid_report *report,
1013 			   u8 *data, int size)
1014 {
1015 	struct ft260_device *dev = hid_get_drvdata(hdev);
1016 	struct ft260_i2c_input_report *xfer = (void *)data;
1017 
1018 	if (xfer->report >= FT260_I2C_REPORT_MIN &&
1019 	    xfer->report <= FT260_I2C_REPORT_MAX) {
1020 		ft260_dbg("i2c resp: rep %#02x len %d\n", xfer->report,
1021 			  xfer->length);
1022 
1023 		memcpy(&dev->read_buf[dev->read_idx], &xfer->data,
1024 		       xfer->length);
1025 		dev->read_idx += xfer->length;
1026 
1027 		if (dev->read_idx == dev->read_len)
1028 			complete(&dev->wait);
1029 
1030 	} else {
1031 		hid_err(hdev, "unknown report: %#02x\n", xfer->report);
1032 		return 0;
1033 	}
1034 	return 1;
1035 }
1036 
1037 static struct hid_driver ft260_driver = {
1038 	.name		= "ft260",
1039 	.id_table	= ft260_devices,
1040 	.probe		= ft260_probe,
1041 	.remove		= ft260_remove,
1042 	.raw_event	= ft260_raw_event,
1043 };
1044 
1045 module_hid_driver(ft260_driver);
1046 MODULE_DESCRIPTION("FTDI FT260 USB HID to I2C host bridge");
1047 MODULE_AUTHOR("Michael Zaidman <michael.zaidman@gmail.com>");
1048 MODULE_LICENSE("GPL v2");
1049