1 /*
2  *   This file is provided under a GPLv2 license.  When using or
3  *   redistributing this file, you may do so under that license.
4  *
5  *   GPL LICENSE SUMMARY
6  *
7  *   Copyright (C) 2016 T-Platforms. All Rights Reserved.
8  *
9  *   This program is free software; you can redistribute it and/or modify it
10  *   under the terms and conditions of the GNU General Public License,
11  *   version 2, as published by the Free Software Foundation.
12  *
13  *   This program is distributed in the hope that it will be useful, but WITHOUT
14  *   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  *   FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16  *   more details.
17  *
18  *   You should have received a copy of the GNU General Public License along
19  *   with this program; if not, it can be found <http://www.gnu.org/licenses/>.
20  *
21  *   The full GNU General Public License is included in this distribution in
22  *   the file called "COPYING".
23  *
24  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
27  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
28  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
34  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  *
36  * IDT PCIe-switch NTB Linux driver
37  *
38  * Contact Information:
39  * Serge Semin <fancer.lancer@gmail.com>, <Sergey.Semin@t-platforms.ru>
40  */
41 /*
42  *           NOTE of the IDT 89HPESx SMBus-slave interface driver
43  *    This driver primarily is developed to have an access to EEPROM device of
44  * IDT PCIe-switches. IDT provides a simple SMBus interface to perform IO-
45  * operations from/to EEPROM, which is located at private (so called Master)
46  * SMBus of switches. Using that interface this the driver creates a simple
47  * binary sysfs-file in the device directory:
48  * /sys/bus/i2c/devices/<bus>-<devaddr>/eeprom
49  * In case if read-only flag is specified in the dts-node of device desription,
50  * User-space applications won't be able to write to the EEPROM sysfs-node.
51  *    Additionally IDT 89HPESx SMBus interface has an ability to write/read
52  * data of device CSRs. This driver exposes debugf-file to perform simple IO
53  * operations using that ability for just basic debug purpose. Particularly
54  * next file is created in the specific debugfs-directory:
55  * /sys/kernel/debug/idt_csr/
56  * Format of the debugfs-node is:
57  * $ cat /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
58  * <CSR address>:<CSR value>
59  * So reading the content of the file gives current CSR address and it value.
60  * If User-space application wishes to change current CSR address,
61  * it can just write a proper value to the sysfs-file:
62  * $ echo "<CSR address>" > /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>
63  * If it wants to change the CSR value as well, the format of the write
64  * operation is:
65  * $ echo "<CSR address>:<CSR value>" > \
66  *        /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
67  * CSR address and value can be any of hexadecimal, decimal or octal format.
68  */
69 
70 #include <linux/kernel.h>
71 #include <linux/init.h>
72 #include <linux/module.h>
73 #include <linux/types.h>
74 #include <linux/sizes.h>
75 #include <linux/slab.h>
76 #include <linux/mutex.h>
77 #include <linux/sysfs.h>
78 #include <linux/debugfs.h>
79 #include <linux/mod_devicetable.h>
80 #include <linux/property.h>
81 #include <linux/i2c.h>
82 #include <linux/pci_ids.h>
83 #include <linux/delay.h>
84 
85 #define IDT_NAME		"89hpesx"
86 #define IDT_89HPESX_DESC	"IDT 89HPESx SMBus-slave interface driver"
87 #define IDT_89HPESX_VER		"1.0"
88 
89 MODULE_DESCRIPTION(IDT_89HPESX_DESC);
90 MODULE_VERSION(IDT_89HPESX_VER);
91 MODULE_LICENSE("GPL v2");
92 MODULE_AUTHOR("T-platforms");
93 
94 /*
95  * csr_dbgdir - CSR read/write operations Debugfs directory
96  */
97 static struct dentry *csr_dbgdir;
98 
99 /*
100  * struct idt_89hpesx_dev - IDT 89HPESx device data structure
101  * @eesize:	Size of EEPROM in bytes (calculated from "idt,eecompatible")
102  * @eero:	EEPROM Read-only flag
103  * @eeaddr:	EEPROM custom address
104  *
105  * @inieecmd:	Initial cmd value for EEPROM read/write operations
106  * @inicsrcmd:	Initial cmd value for CSR read/write operations
107  * @iniccode:	Initialial command code value for IO-operations
108  *
109  * @csr:	CSR address to perform read operation
110  *
111  * @smb_write:	SMBus write method
112  * @smb_read:	SMBus read method
113  * @smb_mtx:	SMBus mutex
114  *
115  * @client:	i2c client used to perform IO operations
116  *
117  * @ee_file:	EEPROM read/write sysfs-file
118  */
119 struct idt_smb_seq;
120 struct idt_89hpesx_dev {
121 	u32 eesize;
122 	bool eero;
123 	u8 eeaddr;
124 
125 	u8 inieecmd;
126 	u8 inicsrcmd;
127 	u8 iniccode;
128 
129 	u16 csr;
130 
131 	int (*smb_write)(struct idt_89hpesx_dev *, const struct idt_smb_seq *);
132 	int (*smb_read)(struct idt_89hpesx_dev *, struct idt_smb_seq *);
133 	struct mutex smb_mtx;
134 
135 	struct i2c_client *client;
136 
137 	struct bin_attribute *ee_file;
138 	struct dentry *csr_dir;
139 };
140 
141 /*
142  * struct idt_smb_seq - sequence of data to be read/written from/to IDT 89HPESx
143  * @ccode:	SMBus command code
144  * @bytecnt:	Byte count of operation
145  * @data:	Data to by written
146  */
147 struct idt_smb_seq {
148 	u8 ccode;
149 	u8 bytecnt;
150 	u8 *data;
151 };
152 
153 /*
154  * struct idt_eeprom_seq - sequence of data to be read/written from/to EEPROM
155  * @cmd:	Transaction CMD
156  * @eeaddr:	EEPROM custom address
157  * @memaddr:	Internal memory address of EEPROM
158  * @data:	Data to be written at the memory address
159  */
160 struct idt_eeprom_seq {
161 	u8 cmd;
162 	u8 eeaddr;
163 	u16 memaddr;
164 	u8 data;
165 } __packed;
166 
167 /*
168  * struct idt_csr_seq - sequence of data to be read/written from/to CSR
169  * @cmd:	Transaction CMD
170  * @csraddr:	Internal IDT device CSR address
171  * @data:	Data to be read/written from/to the CSR address
172  */
173 struct idt_csr_seq {
174 	u8 cmd;
175 	u16 csraddr;
176 	u32 data;
177 } __packed;
178 
179 /*
180  * SMBus command code macros
181  * @CCODE_END:		Indicates the end of transaction
182  * @CCODE_START:	Indicates the start of transaction
183  * @CCODE_CSR:		CSR read/write transaction
184  * @CCODE_EEPROM:	EEPROM read/write transaction
185  * @CCODE_BYTE:		Supplied data has BYTE length
186  * @CCODE_WORD:		Supplied data has WORD length
187  * @CCODE_BLOCK:	Supplied data has variable length passed in bytecnt
188  *			byte right following CCODE byte
189  */
190 #define CCODE_END	((u8)0x01)
191 #define CCODE_START	((u8)0x02)
192 #define CCODE_CSR	((u8)0x00)
193 #define CCODE_EEPROM	((u8)0x04)
194 #define CCODE_BYTE	((u8)0x00)
195 #define CCODE_WORD	((u8)0x20)
196 #define CCODE_BLOCK	((u8)0x40)
197 #define CCODE_PEC	((u8)0x80)
198 
199 /*
200  * EEPROM command macros
201  * @EEPROM_OP_WRITE:	EEPROM write operation
202  * @EEPROM_OP_READ:	EEPROM read operation
203  * @EEPROM_USA:		Use specified address of EEPROM
204  * @EEPROM_NAERR:	EEPROM device is not ready to respond
205  * @EEPROM_LAERR:	EEPROM arbitration loss error
206  * @EEPROM_MSS:		EEPROM misplace start & stop bits error
207  * @EEPROM_WR_CNT:	Bytes count to perform write operation
208  * @EEPROM_WRRD_CNT:	Bytes count to write before reading
209  * @EEPROM_RD_CNT:	Bytes count to perform read operation
210  * @EEPROM_DEF_SIZE:	Fall back size of EEPROM
211  * @EEPROM_DEF_ADDR:	Defatul EEPROM address
212  * @EEPROM_TOUT:	Timeout before retry read operation if eeprom is busy
213  */
214 #define EEPROM_OP_WRITE	((u8)0x00)
215 #define EEPROM_OP_READ	((u8)0x01)
216 #define EEPROM_USA	((u8)0x02)
217 #define EEPROM_NAERR	((u8)0x08)
218 #define EEPROM_LAERR    ((u8)0x10)
219 #define EEPROM_MSS	((u8)0x20)
220 #define EEPROM_WR_CNT	((u8)5)
221 #define EEPROM_WRRD_CNT	((u8)4)
222 #define EEPROM_RD_CNT	((u8)5)
223 #define EEPROM_DEF_SIZE	((u16)4096)
224 #define EEPROM_DEF_ADDR	((u8)0x50)
225 #define EEPROM_TOUT	(100)
226 
227 /*
228  * CSR command macros
229  * @CSR_DWE:		Enable all four bytes of the operation
230  * @CSR_OP_WRITE:	CSR write operation
231  * @CSR_OP_READ:	CSR read operation
232  * @CSR_RERR:		Read operation error
233  * @CSR_WERR:		Write operation error
234  * @CSR_WR_CNT:		Bytes count to perform write operation
235  * @CSR_WRRD_CNT:	Bytes count to write before reading
236  * @CSR_RD_CNT:		Bytes count to perform read operation
237  * @CSR_MAX:		Maximum CSR address
238  * @CSR_DEF:		Default CSR address
239  * @CSR_REAL_ADDR:	CSR real unshifted address
240  */
241 #define CSR_DWE			((u8)0x0F)
242 #define CSR_OP_WRITE		((u8)0x00)
243 #define CSR_OP_READ		((u8)0x10)
244 #define CSR_RERR		((u8)0x40)
245 #define CSR_WERR		((u8)0x80)
246 #define CSR_WR_CNT		((u8)7)
247 #define CSR_WRRD_CNT		((u8)3)
248 #define CSR_RD_CNT		((u8)7)
249 #define CSR_MAX			((u32)0x3FFFF)
250 #define CSR_DEF			((u16)0x0000)
251 #define CSR_REAL_ADDR(val)	((unsigned int)val << 2)
252 
253 /*
254  * IDT 89HPESx basic register
255  * @IDT_VIDDID_CSR:	PCIe VID and DID of IDT 89HPESx
256  * @IDT_VID_MASK:	Mask of VID
257  */
258 #define IDT_VIDDID_CSR	((u32)0x0000)
259 #define IDT_VID_MASK	((u32)0xFFFF)
260 
261 /*
262  * IDT 89HPESx can send NACK when new command is sent before previous one
263  * fininshed execution. In this case driver retries operation
264  * certain times.
265  * @RETRY_CNT:		Number of retries before giving up and fail
266  * @idt_smb_safe:	Generate a retry loop on corresponding SMBus method
267  */
268 #define RETRY_CNT (128)
269 #define idt_smb_safe(ops, args...) ({ \
270 	int __retry = RETRY_CNT; \
271 	s32 __sts; \
272 	do { \
273 		__sts = i2c_smbus_ ## ops ## _data(args); \
274 	} while (__retry-- && __sts < 0); \
275 	__sts; \
276 })
277 
278 /*===========================================================================
279  *                         i2c bus level IO-operations
280  *===========================================================================
281  */
282 
283 /*
284  * idt_smb_write_byte() - SMBus write method when I2C_SMBUS_BYTE_DATA operation
285  *                        is only available
286  * @pdev:	Pointer to the driver data
287  * @seq:	Sequence of data to be written
288  */
289 static int idt_smb_write_byte(struct idt_89hpesx_dev *pdev,
290 			      const struct idt_smb_seq *seq)
291 {
292 	s32 sts;
293 	u8 ccode;
294 	int idx;
295 
296 	/* Loop over the supplied data sending byte one-by-one */
297 	for (idx = 0; idx < seq->bytecnt; idx++) {
298 		/* Collect the command code byte */
299 		ccode = seq->ccode | CCODE_BYTE;
300 		if (idx == 0)
301 			ccode |= CCODE_START;
302 		if (idx == seq->bytecnt - 1)
303 			ccode |= CCODE_END;
304 
305 		/* Send data to the device */
306 		sts = idt_smb_safe(write_byte, pdev->client, ccode,
307 			seq->data[idx]);
308 		if (sts != 0)
309 			return (int)sts;
310 	}
311 
312 	return 0;
313 }
314 
315 /*
316  * idt_smb_read_byte() - SMBus read method when I2C_SMBUS_BYTE_DATA operation
317  *                        is only available
318  * @pdev:	Pointer to the driver data
319  * @seq:	Buffer to read data to
320  */
321 static int idt_smb_read_byte(struct idt_89hpesx_dev *pdev,
322 			     struct idt_smb_seq *seq)
323 {
324 	s32 sts;
325 	u8 ccode;
326 	int idx;
327 
328 	/* Loop over the supplied buffer receiving byte one-by-one */
329 	for (idx = 0; idx < seq->bytecnt; idx++) {
330 		/* Collect the command code byte */
331 		ccode = seq->ccode | CCODE_BYTE;
332 		if (idx == 0)
333 			ccode |= CCODE_START;
334 		if (idx == seq->bytecnt - 1)
335 			ccode |= CCODE_END;
336 
337 		/* Read data from the device */
338 		sts = idt_smb_safe(read_byte, pdev->client, ccode);
339 		if (sts < 0)
340 			return (int)sts;
341 
342 		seq->data[idx] = (u8)sts;
343 	}
344 
345 	return 0;
346 }
347 
348 /*
349  * idt_smb_write_word() - SMBus write method when I2C_SMBUS_BYTE_DATA and
350  *                        I2C_FUNC_SMBUS_WORD_DATA operations are available
351  * @pdev:	Pointer to the driver data
352  * @seq:	Sequence of data to be written
353  */
354 static int idt_smb_write_word(struct idt_89hpesx_dev *pdev,
355 			      const struct idt_smb_seq *seq)
356 {
357 	s32 sts;
358 	u8 ccode;
359 	int idx, evencnt;
360 
361 	/* Calculate the even count of data to send */
362 	evencnt = seq->bytecnt - (seq->bytecnt % 2);
363 
364 	/* Loop over the supplied data sending two bytes at a time */
365 	for (idx = 0; idx < evencnt; idx += 2) {
366 		/* Collect the command code byte */
367 		ccode = seq->ccode | CCODE_WORD;
368 		if (idx == 0)
369 			ccode |= CCODE_START;
370 		if (idx == evencnt - 2)
371 			ccode |= CCODE_END;
372 
373 		/* Send word data to the device */
374 		sts = idt_smb_safe(write_word, pdev->client, ccode,
375 			*(u16 *)&seq->data[idx]);
376 		if (sts != 0)
377 			return (int)sts;
378 	}
379 
380 	/* If there is odd number of bytes then send just one last byte */
381 	if (seq->bytecnt != evencnt) {
382 		/* Collect the command code byte */
383 		ccode = seq->ccode | CCODE_BYTE | CCODE_END;
384 		if (idx == 0)
385 			ccode |= CCODE_START;
386 
387 		/* Send byte data to the device */
388 		sts = idt_smb_safe(write_byte, pdev->client, ccode,
389 			seq->data[idx]);
390 		if (sts != 0)
391 			return (int)sts;
392 	}
393 
394 	return 0;
395 }
396 
397 /*
398  * idt_smb_read_word() - SMBus read method when I2C_SMBUS_BYTE_DATA and
399  *                       I2C_FUNC_SMBUS_WORD_DATA operations are available
400  * @pdev:	Pointer to the driver data
401  * @seq:	Buffer to read data to
402  */
403 static int idt_smb_read_word(struct idt_89hpesx_dev *pdev,
404 			     struct idt_smb_seq *seq)
405 {
406 	s32 sts;
407 	u8 ccode;
408 	int idx, evencnt;
409 
410 	/* Calculate the even count of data to send */
411 	evencnt = seq->bytecnt - (seq->bytecnt % 2);
412 
413 	/* Loop over the supplied data reading two bytes at a time */
414 	for (idx = 0; idx < evencnt; idx += 2) {
415 		/* Collect the command code byte */
416 		ccode = seq->ccode | CCODE_WORD;
417 		if (idx == 0)
418 			ccode |= CCODE_START;
419 		if (idx == evencnt - 2)
420 			ccode |= CCODE_END;
421 
422 		/* Read word data from the device */
423 		sts = idt_smb_safe(read_word, pdev->client, ccode);
424 		if (sts < 0)
425 			return (int)sts;
426 
427 		*(u16 *)&seq->data[idx] = (u16)sts;
428 	}
429 
430 	/* If there is odd number of bytes then receive just one last byte */
431 	if (seq->bytecnt != evencnt) {
432 		/* Collect the command code byte */
433 		ccode = seq->ccode | CCODE_BYTE | CCODE_END;
434 		if (idx == 0)
435 			ccode |= CCODE_START;
436 
437 		/* Read last data byte from the device */
438 		sts = idt_smb_safe(read_byte, pdev->client, ccode);
439 		if (sts < 0)
440 			return (int)sts;
441 
442 		seq->data[idx] = (u8)sts;
443 	}
444 
445 	return 0;
446 }
447 
448 /*
449  * idt_smb_write_block() - SMBus write method when I2C_SMBUS_BLOCK_DATA
450  *                         operation is available
451  * @pdev:	Pointer to the driver data
452  * @seq:	Sequence of data to be written
453  */
454 static int idt_smb_write_block(struct idt_89hpesx_dev *pdev,
455 			       const struct idt_smb_seq *seq)
456 {
457 	u8 ccode;
458 
459 	/* Return error if too much data passed to send */
460 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
461 		return -EINVAL;
462 
463 	/* Collect the command code byte */
464 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
465 
466 	/* Send block of data to the device */
467 	return idt_smb_safe(write_block, pdev->client, ccode, seq->bytecnt,
468 		seq->data);
469 }
470 
471 /*
472  * idt_smb_read_block() - SMBus read method when I2C_SMBUS_BLOCK_DATA
473  *                        operation is available
474  * @pdev:	Pointer to the driver data
475  * @seq:	Buffer to read data to
476  */
477 static int idt_smb_read_block(struct idt_89hpesx_dev *pdev,
478 			      struct idt_smb_seq *seq)
479 {
480 	s32 sts;
481 	u8 ccode;
482 
483 	/* Return error if too much data passed to send */
484 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
485 		return -EINVAL;
486 
487 	/* Collect the command code byte */
488 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
489 
490 	/* Read block of data from the device */
491 	sts = idt_smb_safe(read_block, pdev->client, ccode, seq->data);
492 	if (sts != seq->bytecnt)
493 		return (sts < 0 ? sts : -ENODATA);
494 
495 	return 0;
496 }
497 
498 /*
499  * idt_smb_write_i2c_block() - SMBus write method when I2C_SMBUS_I2C_BLOCK_DATA
500  *                             operation is available
501  * @pdev:	Pointer to the driver data
502  * @seq:	Sequence of data to be written
503  *
504  * NOTE It's usual SMBus write block operation, except the actual data length is
505  * sent as first byte of data
506  */
507 static int idt_smb_write_i2c_block(struct idt_89hpesx_dev *pdev,
508 				   const struct idt_smb_seq *seq)
509 {
510 	u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
511 
512 	/* Return error if too much data passed to send */
513 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
514 		return -EINVAL;
515 
516 	/* Collect the data to send. Length byte must be added prior the data */
517 	buf[0] = seq->bytecnt;
518 	memcpy(&buf[1], seq->data, seq->bytecnt);
519 
520 	/* Collect the command code byte */
521 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
522 
523 	/* Send length and block of data to the device */
524 	return idt_smb_safe(write_i2c_block, pdev->client, ccode,
525 		seq->bytecnt + 1, buf);
526 }
527 
528 /*
529  * idt_smb_read_i2c_block() - SMBus read method when I2C_SMBUS_I2C_BLOCK_DATA
530  *                            operation is available
531  * @pdev:	Pointer to the driver data
532  * @seq:	Buffer to read data to
533  *
534  * NOTE It's usual SMBus read block operation, except the actual data length is
535  * retrieved as first byte of data
536  */
537 static int idt_smb_read_i2c_block(struct idt_89hpesx_dev *pdev,
538 				  struct idt_smb_seq *seq)
539 {
540 	u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
541 	s32 sts;
542 
543 	/* Return error if too much data passed to send */
544 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
545 		return -EINVAL;
546 
547 	/* Collect the command code byte */
548 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
549 
550 	/* Read length and block of data from the device */
551 	sts = idt_smb_safe(read_i2c_block, pdev->client, ccode,
552 		seq->bytecnt + 1, buf);
553 	if (sts != seq->bytecnt + 1)
554 		return (sts < 0 ? sts : -ENODATA);
555 	if (buf[0] != seq->bytecnt)
556 		return -ENODATA;
557 
558 	/* Copy retrieved data to the output data buffer */
559 	memcpy(seq->data, &buf[1], seq->bytecnt);
560 
561 	return 0;
562 }
563 
564 /*===========================================================================
565  *                          EEPROM IO-operations
566  *===========================================================================
567  */
568 
569 /*
570  * idt_eeprom_read_byte() - read just one byte from EEPROM
571  * @pdev:	Pointer to the driver data
572  * @memaddr:	Start EEPROM memory address
573  * @data:	Data to be written to EEPROM
574  */
575 static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr,
576 				u8 *data)
577 {
578 	struct device *dev = &pdev->client->dev;
579 	struct idt_eeprom_seq eeseq;
580 	struct idt_smb_seq smbseq;
581 	int ret, retry;
582 
583 	/* Initialize SMBus sequence fields */
584 	smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
585 	smbseq.data = (u8 *)&eeseq;
586 
587 	/*
588 	 * Sometimes EEPROM may respond with NACK if it's busy with previous
589 	 * operation, so we need to perform a few attempts of read cycle
590 	 */
591 	retry = RETRY_CNT;
592 	do {
593 		/* Send EEPROM memory address to read data from */
594 		smbseq.bytecnt = EEPROM_WRRD_CNT;
595 		eeseq.cmd = pdev->inieecmd | EEPROM_OP_READ;
596 		eeseq.eeaddr = pdev->eeaddr;
597 		eeseq.memaddr = cpu_to_le16(memaddr);
598 		ret = pdev->smb_write(pdev, &smbseq);
599 		if (ret != 0) {
600 			dev_err(dev, "Failed to init eeprom addr 0x%02hhx",
601 				memaddr);
602 			break;
603 		}
604 
605 		/* Perform read operation */
606 		smbseq.bytecnt = EEPROM_RD_CNT;
607 		ret = pdev->smb_read(pdev, &smbseq);
608 		if (ret != 0) {
609 			dev_err(dev, "Failed to read eeprom data 0x%02hhx",
610 				memaddr);
611 			break;
612 		}
613 
614 		/* Restart read operation if the device is busy */
615 		if (retry && (eeseq.cmd & EEPROM_NAERR)) {
616 			dev_dbg(dev, "EEPROM busy, retry reading after %d ms",
617 				EEPROM_TOUT);
618 			msleep(EEPROM_TOUT);
619 			continue;
620 		}
621 
622 		/* Check whether IDT successfully read data from EEPROM */
623 		if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
624 			dev_err(dev,
625 				"Communication with eeprom failed, cmd 0x%hhx",
626 				eeseq.cmd);
627 			ret = -EREMOTEIO;
628 			break;
629 		}
630 
631 		/* Save retrieved data and exit the loop */
632 		*data = eeseq.data;
633 		break;
634 	} while (retry--);
635 
636 	/* Return the status of operation */
637 	return ret;
638 }
639 
640 /*
641  * idt_eeprom_write() - EEPROM write operation
642  * @pdev:	Pointer to the driver data
643  * @memaddr:	Start EEPROM memory address
644  * @len:	Length of data to be written
645  * @data:	Data to be written to EEPROM
646  */
647 static int idt_eeprom_write(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
648 			    const u8 *data)
649 {
650 	struct device *dev = &pdev->client->dev;
651 	struct idt_eeprom_seq eeseq;
652 	struct idt_smb_seq smbseq;
653 	int ret;
654 	u16 idx;
655 
656 	/* Initialize SMBus sequence fields */
657 	smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
658 	smbseq.data = (u8 *)&eeseq;
659 
660 	/* Send data byte-by-byte, checking if it is successfully written */
661 	for (idx = 0; idx < len; idx++, memaddr++) {
662 		/* Lock IDT SMBus device */
663 		mutex_lock(&pdev->smb_mtx);
664 
665 		/* Perform write operation */
666 		smbseq.bytecnt = EEPROM_WR_CNT;
667 		eeseq.cmd = pdev->inieecmd | EEPROM_OP_WRITE;
668 		eeseq.eeaddr = pdev->eeaddr;
669 		eeseq.memaddr = cpu_to_le16(memaddr);
670 		eeseq.data = data[idx];
671 		ret = pdev->smb_write(pdev, &smbseq);
672 		if (ret != 0) {
673 			dev_err(dev,
674 				"Failed to write 0x%04hx:0x%02hhx to eeprom",
675 				memaddr, data[idx]);
676 			goto err_mutex_unlock;
677 		}
678 
679 		/*
680 		 * Check whether the data is successfully written by reading
681 		 * from the same EEPROM memory address.
682 		 */
683 		eeseq.data = ~data[idx];
684 		ret = idt_eeprom_read_byte(pdev, memaddr, &eeseq.data);
685 		if (ret != 0)
686 			goto err_mutex_unlock;
687 
688 		/* Check whether the read byte is the same as written one */
689 		if (eeseq.data != data[idx]) {
690 			dev_err(dev, "Values don't match 0x%02hhx != 0x%02hhx",
691 				eeseq.data, data[idx]);
692 			ret = -EREMOTEIO;
693 			goto err_mutex_unlock;
694 		}
695 
696 		/* Unlock IDT SMBus device */
697 err_mutex_unlock:
698 		mutex_unlock(&pdev->smb_mtx);
699 		if (ret != 0)
700 			return ret;
701 	}
702 
703 	return 0;
704 }
705 
706 /*
707  * idt_eeprom_read() - EEPROM read operation
708  * @pdev:	Pointer to the driver data
709  * @memaddr:	Start EEPROM memory address
710  * @len:	Length of data to read
711  * @buf:	Buffer to read data to
712  */
713 static int idt_eeprom_read(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
714 			   u8 *buf)
715 {
716 	int ret;
717 	u16 idx;
718 
719 	/* Read data byte-by-byte, retrying if it wasn't successful */
720 	for (idx = 0; idx < len; idx++, memaddr++) {
721 		/* Lock IDT SMBus device */
722 		mutex_lock(&pdev->smb_mtx);
723 
724 		/* Just read the byte to the buffer */
725 		ret = idt_eeprom_read_byte(pdev, memaddr, &buf[idx]);
726 
727 		/* Unlock IDT SMBus device */
728 		mutex_unlock(&pdev->smb_mtx);
729 
730 		/* Return error if read operation failed */
731 		if (ret != 0)
732 			return ret;
733 	}
734 
735 	return 0;
736 }
737 
738 /*===========================================================================
739  *                          CSR IO-operations
740  *===========================================================================
741  */
742 
743 /*
744  * idt_csr_write() - CSR write operation
745  * @pdev:	Pointer to the driver data
746  * @csraddr:	CSR address (with no two LS bits)
747  * @data:	Data to be written to CSR
748  */
749 static int idt_csr_write(struct idt_89hpesx_dev *pdev, u16 csraddr,
750 			 const u32 data)
751 {
752 	struct device *dev = &pdev->client->dev;
753 	struct idt_csr_seq csrseq;
754 	struct idt_smb_seq smbseq;
755 	int ret;
756 
757 	/* Initialize SMBus sequence fields */
758 	smbseq.ccode = pdev->iniccode | CCODE_CSR;
759 	smbseq.data = (u8 *)&csrseq;
760 
761 	/* Lock IDT SMBus device */
762 	mutex_lock(&pdev->smb_mtx);
763 
764 	/* Perform write operation */
765 	smbseq.bytecnt = CSR_WR_CNT;
766 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_WRITE;
767 	csrseq.csraddr = cpu_to_le16(csraddr);
768 	csrseq.data = cpu_to_le32(data);
769 	ret = pdev->smb_write(pdev, &smbseq);
770 	if (ret != 0) {
771 		dev_err(dev, "Failed to write 0x%04x: 0x%04x to csr",
772 			CSR_REAL_ADDR(csraddr), data);
773 		goto err_mutex_unlock;
774 	}
775 
776 	/* Send CSR address to read data from */
777 	smbseq.bytecnt = CSR_WRRD_CNT;
778 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
779 	ret = pdev->smb_write(pdev, &smbseq);
780 	if (ret != 0) {
781 		dev_err(dev, "Failed to init csr address 0x%04x",
782 			CSR_REAL_ADDR(csraddr));
783 		goto err_mutex_unlock;
784 	}
785 
786 	/* Perform read operation */
787 	smbseq.bytecnt = CSR_RD_CNT;
788 	ret = pdev->smb_read(pdev, &smbseq);
789 	if (ret != 0) {
790 		dev_err(dev, "Failed to read csr 0x%04x",
791 			CSR_REAL_ADDR(csraddr));
792 		goto err_mutex_unlock;
793 	}
794 
795 	/* Check whether IDT successfully retrieved CSR data */
796 	if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
797 		dev_err(dev, "IDT failed to perform CSR r/w");
798 		ret = -EREMOTEIO;
799 		goto err_mutex_unlock;
800 	}
801 
802 	/* Unlock IDT SMBus device */
803 err_mutex_unlock:
804 	mutex_unlock(&pdev->smb_mtx);
805 
806 	return ret;
807 }
808 
809 /*
810  * idt_csr_read() - CSR read operation
811  * @pdev:	Pointer to the driver data
812  * @csraddr:	CSR address (with no two LS bits)
813  * @data:	Data to be written to CSR
814  */
815 static int idt_csr_read(struct idt_89hpesx_dev *pdev, u16 csraddr, u32 *data)
816 {
817 	struct device *dev = &pdev->client->dev;
818 	struct idt_csr_seq csrseq;
819 	struct idt_smb_seq smbseq;
820 	int ret;
821 
822 	/* Initialize SMBus sequence fields */
823 	smbseq.ccode = pdev->iniccode | CCODE_CSR;
824 	smbseq.data = (u8 *)&csrseq;
825 
826 	/* Lock IDT SMBus device */
827 	mutex_lock(&pdev->smb_mtx);
828 
829 	/* Send CSR register address before reading it */
830 	smbseq.bytecnt = CSR_WRRD_CNT;
831 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
832 	csrseq.csraddr = cpu_to_le16(csraddr);
833 	ret = pdev->smb_write(pdev, &smbseq);
834 	if (ret != 0) {
835 		dev_err(dev, "Failed to init csr address 0x%04x",
836 			CSR_REAL_ADDR(csraddr));
837 		goto err_mutex_unlock;
838 	}
839 
840 	/* Perform read operation */
841 	smbseq.bytecnt = CSR_RD_CNT;
842 	ret = pdev->smb_read(pdev, &smbseq);
843 	if (ret != 0) {
844 		dev_err(dev, "Failed to read csr 0x%04hx",
845 			CSR_REAL_ADDR(csraddr));
846 		goto err_mutex_unlock;
847 	}
848 
849 	/* Check whether IDT successfully retrieved CSR data */
850 	if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
851 		dev_err(dev, "IDT failed to perform CSR r/w");
852 		ret = -EREMOTEIO;
853 		goto err_mutex_unlock;
854 	}
855 
856 	/* Save data retrieved from IDT */
857 	*data = le32_to_cpu(csrseq.data);
858 
859 	/* Unlock IDT SMBus device */
860 err_mutex_unlock:
861 	mutex_unlock(&pdev->smb_mtx);
862 
863 	return ret;
864 }
865 
866 /*===========================================================================
867  *                          Sysfs/debugfs-nodes IO-operations
868  *===========================================================================
869  */
870 
871 /*
872  * eeprom_write() - EEPROM sysfs-node write callback
873  * @filep:	Pointer to the file system node
874  * @kobj:	Pointer to the kernel object related to the sysfs-node
875  * @attr:	Attributes of the file
876  * @buf:	Buffer to write data to
877  * @off:	Offset at which data should be written to
878  * @count:	Number of bytes to write
879  */
880 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
881 			    struct bin_attribute *attr,
882 			    char *buf, loff_t off, size_t count)
883 {
884 	struct idt_89hpesx_dev *pdev;
885 	int ret;
886 
887 	/* Retrieve driver data */
888 	pdev = dev_get_drvdata(kobj_to_dev(kobj));
889 
890 	/* Perform EEPROM write operation */
891 	ret = idt_eeprom_write(pdev, (u16)off, (u16)count, (u8 *)buf);
892 	return (ret != 0 ? ret : count);
893 }
894 
895 /*
896  * eeprom_read() - EEPROM sysfs-node read callback
897  * @filep:	Pointer to the file system node
898  * @kobj:	Pointer to the kernel object related to the sysfs-node
899  * @attr:	Attributes of the file
900  * @buf:	Buffer to write data to
901  * @off:	Offset at which data should be written to
902  * @count:	Number of bytes to write
903  */
904 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
905 			   struct bin_attribute *attr,
906 			   char *buf, loff_t off, size_t count)
907 {
908 	struct idt_89hpesx_dev *pdev;
909 	int ret;
910 
911 	/* Retrieve driver data */
912 	pdev = dev_get_drvdata(kobj_to_dev(kobj));
913 
914 	/* Perform EEPROM read operation */
915 	ret = idt_eeprom_read(pdev, (u16)off, (u16)count, (u8 *)buf);
916 	return (ret != 0 ? ret : count);
917 }
918 
919 /*
920  * idt_dbgfs_csr_write() - CSR debugfs-node write callback
921  * @filep:	Pointer to the file system file descriptor
922  * @buf:	Buffer to read data from
923  * @count:	Size of the buffer
924  * @offp:	Offset within the file
925  *
926  * It accepts either "0x<reg addr>:0x<value>" for saving register address
927  * and writing value to specified DWORD register or "0x<reg addr>" for
928  * just saving register address in order to perform next read operation.
929  *
930  * WARNING No spaces are allowed. Incoming string must be strictly formated as:
931  * "<reg addr>:<value>". Register address must be aligned within 4 bytes
932  * (one DWORD).
933  */
934 static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf,
935 				   size_t count, loff_t *offp)
936 {
937 	struct idt_89hpesx_dev *pdev = filep->private_data;
938 	char *colon_ch, *csraddr_str, *csrval_str;
939 	int ret, csraddr_len;
940 	u32 csraddr, csrval;
941 	char *buf;
942 
943 	/* Copy data from User-space */
944 	buf = kmalloc(count + 1, GFP_KERNEL);
945 	if (!buf)
946 		return -ENOMEM;
947 
948 	ret = simple_write_to_buffer(buf, count, offp, ubuf, count);
949 	if (ret < 0)
950 		goto free_buf;
951 	buf[count] = 0;
952 
953 	/* Find position of colon in the buffer */
954 	colon_ch = strnchr(buf, count, ':');
955 
956 	/*
957 	 * If there is colon passed then new CSR value should be parsed as
958 	 * well, so allocate buffer for CSR address substring.
959 	 * If no colon is found, then string must have just one number with
960 	 * no new CSR value
961 	 */
962 	if (colon_ch != NULL) {
963 		csraddr_len = colon_ch - buf;
964 		csraddr_str =
965 			kmalloc(csraddr_len + 1, GFP_KERNEL);
966 		if (csraddr_str == NULL) {
967 			ret = -ENOMEM;
968 			goto free_buf;
969 		}
970 		/* Copy the register address to the substring buffer */
971 		strncpy(csraddr_str, buf, csraddr_len);
972 		csraddr_str[csraddr_len] = '\0';
973 		/* Register value must follow the colon */
974 		csrval_str = colon_ch + 1;
975 	} else /* if (str_colon == NULL) */ {
976 		csraddr_str = (char *)buf; /* Just to shut warning up */
977 		csraddr_len = strnlen(csraddr_str, count);
978 		csrval_str = NULL;
979 	}
980 
981 	/* Convert CSR address to u32 value */
982 	ret = kstrtou32(csraddr_str, 0, &csraddr);
983 	if (ret != 0)
984 		goto free_csraddr_str;
985 
986 	/* Check whether passed register address is valid */
987 	if (csraddr > CSR_MAX || !IS_ALIGNED(csraddr, SZ_4)) {
988 		ret = -EINVAL;
989 		goto free_csraddr_str;
990 	}
991 
992 	/* Shift register address to the right so to have u16 address */
993 	pdev->csr = (csraddr >> 2);
994 
995 	/* Parse new CSR value and send it to IDT, if colon has been found */
996 	if (colon_ch != NULL) {
997 		ret = kstrtou32(csrval_str, 0, &csrval);
998 		if (ret != 0)
999 			goto free_csraddr_str;
1000 
1001 		ret = idt_csr_write(pdev, pdev->csr, csrval);
1002 		if (ret != 0)
1003 			goto free_csraddr_str;
1004 	}
1005 
1006 	/* Free memory only if colon has been found */
1007 free_csraddr_str:
1008 	if (colon_ch != NULL)
1009 		kfree(csraddr_str);
1010 
1011 	/* Free buffer allocated for data retrieved from User-space */
1012 free_buf:
1013 	kfree(buf);
1014 
1015 	return (ret != 0 ? ret : count);
1016 }
1017 
1018 /*
1019  * idt_dbgfs_csr_read() - CSR debugfs-node read callback
1020  * @filep:	Pointer to the file system file descriptor
1021  * @buf:	Buffer to write data to
1022  * @count:	Size of the buffer
1023  * @offp:	Offset within the file
1024  *
1025  * It just prints the pair "0x<reg addr>:0x<value>" to passed buffer.
1026  */
1027 #define CSRBUF_SIZE	((size_t)32)
1028 static ssize_t idt_dbgfs_csr_read(struct file *filep, char __user *ubuf,
1029 				  size_t count, loff_t *offp)
1030 {
1031 	struct idt_89hpesx_dev *pdev = filep->private_data;
1032 	u32 csraddr, csrval;
1033 	char buf[CSRBUF_SIZE];
1034 	int ret, size;
1035 
1036 	/* Perform CSR read operation */
1037 	ret = idt_csr_read(pdev, pdev->csr, &csrval);
1038 	if (ret != 0)
1039 		return ret;
1040 
1041 	/* Shift register address to the left so to have real address */
1042 	csraddr = ((u32)pdev->csr << 2);
1043 
1044 	/* Print the "0x<reg addr>:0x<value>" to buffer */
1045 	size = snprintf(buf, CSRBUF_SIZE, "0x%05x:0x%08x\n",
1046 		(unsigned int)csraddr, (unsigned int)csrval);
1047 
1048 	/* Copy data to User-space */
1049 	return simple_read_from_buffer(ubuf, count, offp, buf, size);
1050 }
1051 
1052 /*
1053  * eeprom_attribute - EEPROM sysfs-node attributes
1054  *
1055  * NOTE Size will be changed in compliance with OF node. EEPROM attribute will
1056  * be read-only as well if the corresponding flag is specified in OF node.
1057  */
1058 static BIN_ATTR_RW(eeprom, EEPROM_DEF_SIZE);
1059 
1060 /*
1061  * csr_dbgfs_ops - CSR debugfs-node read/write operations
1062  */
1063 static const struct file_operations csr_dbgfs_ops = {
1064 	.owner = THIS_MODULE,
1065 	.open = simple_open,
1066 	.write = idt_dbgfs_csr_write,
1067 	.read = idt_dbgfs_csr_read
1068 };
1069 
1070 /*===========================================================================
1071  *                       Driver init/deinit methods
1072  *===========================================================================
1073  */
1074 
1075 /*
1076  * idt_set_defval() - disable EEPROM access by default
1077  * @pdev:	Pointer to the driver data
1078  */
1079 static void idt_set_defval(struct idt_89hpesx_dev *pdev)
1080 {
1081 	/* If OF info is missing then use next values */
1082 	pdev->eesize = 0;
1083 	pdev->eero = true;
1084 	pdev->inieecmd = 0;
1085 	pdev->eeaddr = 0;
1086 }
1087 
1088 static const struct i2c_device_id ee_ids[];
1089 
1090 /*
1091  * idt_ee_match_id() - check whether the node belongs to compatible EEPROMs
1092  */
1093 static const struct i2c_device_id *idt_ee_match_id(struct fwnode_handle *fwnode)
1094 {
1095 	const struct i2c_device_id *id = ee_ids;
1096 	const char *compatible, *p;
1097 	char devname[I2C_NAME_SIZE];
1098 	int ret;
1099 
1100 	ret = fwnode_property_read_string(fwnode, "compatible", &compatible);
1101 	if (ret)
1102 		return NULL;
1103 
1104 	p = strchr(compatible, ',');
1105 	strlcpy(devname, p ? p + 1 : compatible, sizeof(devname));
1106 	/* Search through the device name */
1107 	while (id->name[0]) {
1108 		if (strcmp(devname, id->name) == 0)
1109 			return id;
1110 		id++;
1111 	}
1112 	return NULL;
1113 }
1114 
1115 /*
1116  * idt_get_fw_data() - get IDT i2c-device parameters from device tree
1117  * @pdev:	Pointer to the driver data
1118  */
1119 static void idt_get_fw_data(struct idt_89hpesx_dev *pdev)
1120 {
1121 	struct device *dev = &pdev->client->dev;
1122 	struct fwnode_handle *fwnode;
1123 	const struct i2c_device_id *ee_id = NULL;
1124 	u32 eeprom_addr;
1125 	int ret;
1126 
1127 	device_for_each_child_node(dev, fwnode) {
1128 		ee_id = idt_ee_match_id(fwnode);
1129 		if (!ee_id) {
1130 			dev_warn(dev, "Skip unsupported EEPROM device");
1131 			continue;
1132 		} else
1133 			break;
1134 	}
1135 
1136 	/* If there is no fwnode EEPROM device, then set zero size */
1137 	if (!ee_id) {
1138 		dev_warn(dev, "No fwnode, EEPROM access disabled");
1139 		idt_set_defval(pdev);
1140 		return;
1141 	}
1142 
1143 	/* Retrieve EEPROM size */
1144 	pdev->eesize = (u32)ee_id->driver_data;
1145 
1146 	/* Get custom EEPROM address from 'reg' attribute */
1147 	ret = fwnode_property_read_u32(fwnode, "reg", &eeprom_addr);
1148 	if (ret || (eeprom_addr == 0)) {
1149 		dev_warn(dev, "No EEPROM reg found, use default address 0x%x",
1150 			 EEPROM_DEF_ADDR);
1151 		pdev->inieecmd = 0;
1152 		pdev->eeaddr = EEPROM_DEF_ADDR << 1;
1153 	} else {
1154 		pdev->inieecmd = EEPROM_USA;
1155 		pdev->eeaddr = eeprom_addr << 1;
1156 	}
1157 
1158 	/* Check EEPROM 'read-only' flag */
1159 	if (fwnode_property_read_bool(fwnode, "read-only"))
1160 		pdev->eero = true;
1161 	else /* if (!fwnode_property_read_bool(node, "read-only")) */
1162 		pdev->eero = false;
1163 
1164 	dev_info(dev, "EEPROM of %d bytes found by 0x%x",
1165 		pdev->eesize, pdev->eeaddr);
1166 }
1167 
1168 /*
1169  * idt_create_pdev() - create and init data structure of the driver
1170  * @client:	i2c client of IDT PCIe-switch device
1171  */
1172 static struct idt_89hpesx_dev *idt_create_pdev(struct i2c_client *client)
1173 {
1174 	struct idt_89hpesx_dev *pdev;
1175 
1176 	/* Allocate memory for driver data */
1177 	pdev = devm_kmalloc(&client->dev, sizeof(struct idt_89hpesx_dev),
1178 		GFP_KERNEL);
1179 	if (pdev == NULL)
1180 		return ERR_PTR(-ENOMEM);
1181 
1182 	/* Initialize basic fields of the data */
1183 	pdev->client = client;
1184 	i2c_set_clientdata(client, pdev);
1185 
1186 	/* Read firmware nodes information */
1187 	idt_get_fw_data(pdev);
1188 
1189 	/* Initialize basic CSR CMD field - use full DWORD-sized r/w ops */
1190 	pdev->inicsrcmd = CSR_DWE;
1191 	pdev->csr = CSR_DEF;
1192 
1193 	/* Enable Packet Error Checking if it's supported by adapter */
1194 	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_PEC)) {
1195 		pdev->iniccode = CCODE_PEC;
1196 		client->flags |= I2C_CLIENT_PEC;
1197 	} else /* PEC is unsupported */ {
1198 		pdev->iniccode = 0;
1199 	}
1200 
1201 	return pdev;
1202 }
1203 
1204 /*
1205  * idt_free_pdev() - free data structure of the driver
1206  * @pdev:	Pointer to the driver data
1207  */
1208 static void idt_free_pdev(struct idt_89hpesx_dev *pdev)
1209 {
1210 	/* Clear driver data from device private field */
1211 	i2c_set_clientdata(pdev->client, NULL);
1212 }
1213 
1214 /*
1215  * idt_set_smbus_ops() - set supported SMBus operations
1216  * @pdev:	Pointer to the driver data
1217  * Return status of smbus check operations
1218  */
1219 static int idt_set_smbus_ops(struct idt_89hpesx_dev *pdev)
1220 {
1221 	struct i2c_adapter *adapter = pdev->client->adapter;
1222 	struct device *dev = &pdev->client->dev;
1223 
1224 	/* Check i2c adapter read functionality */
1225 	if (i2c_check_functionality(adapter,
1226 				    I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
1227 		pdev->smb_read = idt_smb_read_block;
1228 		dev_dbg(dev, "SMBus block-read op chosen");
1229 	} else if (i2c_check_functionality(adapter,
1230 					   I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
1231 		pdev->smb_read = idt_smb_read_i2c_block;
1232 		dev_dbg(dev, "SMBus i2c-block-read op chosen");
1233 	} else if (i2c_check_functionality(adapter,
1234 					   I2C_FUNC_SMBUS_READ_WORD_DATA) &&
1235 		   i2c_check_functionality(adapter,
1236 					   I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
1237 		pdev->smb_read = idt_smb_read_word;
1238 		dev_warn(dev, "Use slow word/byte SMBus read ops");
1239 	} else if (i2c_check_functionality(adapter,
1240 					   I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
1241 		pdev->smb_read = idt_smb_read_byte;
1242 		dev_warn(dev, "Use slow byte SMBus read op");
1243 	} else /* no supported smbus read operations */ {
1244 		dev_err(dev, "No supported SMBus read op");
1245 		return -EPFNOSUPPORT;
1246 	}
1247 
1248 	/* Check i2c adapter write functionality */
1249 	if (i2c_check_functionality(adapter,
1250 				    I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)) {
1251 		pdev->smb_write = idt_smb_write_block;
1252 		dev_dbg(dev, "SMBus block-write op chosen");
1253 	} else if (i2c_check_functionality(adapter,
1254 					   I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
1255 		pdev->smb_write = idt_smb_write_i2c_block;
1256 		dev_dbg(dev, "SMBus i2c-block-write op chosen");
1257 	} else if (i2c_check_functionality(adapter,
1258 					   I2C_FUNC_SMBUS_WRITE_WORD_DATA) &&
1259 		   i2c_check_functionality(adapter,
1260 					   I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
1261 		pdev->smb_write = idt_smb_write_word;
1262 		dev_warn(dev, "Use slow word/byte SMBus write op");
1263 	} else if (i2c_check_functionality(adapter,
1264 					   I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
1265 		pdev->smb_write = idt_smb_write_byte;
1266 		dev_warn(dev, "Use slow byte SMBus write op");
1267 	} else /* no supported smbus write operations */ {
1268 		dev_err(dev, "No supported SMBus write op");
1269 		return -EPFNOSUPPORT;
1270 	}
1271 
1272 	/* Initialize IDT SMBus slave interface mutex */
1273 	mutex_init(&pdev->smb_mtx);
1274 
1275 	return 0;
1276 }
1277 
1278 /*
1279  * idt_check_dev() - check whether it's really IDT 89HPESx device
1280  * @pdev:	Pointer to the driver data
1281  * Return status of i2c adapter check operation
1282  */
1283 static int idt_check_dev(struct idt_89hpesx_dev *pdev)
1284 {
1285 	struct device *dev = &pdev->client->dev;
1286 	u32 viddid;
1287 	int ret;
1288 
1289 	/* Read VID and DID directly from IDT memory space */
1290 	ret = idt_csr_read(pdev, IDT_VIDDID_CSR, &viddid);
1291 	if (ret != 0) {
1292 		dev_err(dev, "Failed to read VID/DID");
1293 		return ret;
1294 	}
1295 
1296 	/* Check whether it's IDT device */
1297 	if ((viddid & IDT_VID_MASK) != PCI_VENDOR_ID_IDT) {
1298 		dev_err(dev, "Got unsupported VID/DID: 0x%08x", viddid);
1299 		return -ENODEV;
1300 	}
1301 
1302 	dev_info(dev, "Found IDT 89HPES device VID:0x%04x, DID:0x%04x",
1303 		(viddid & IDT_VID_MASK), (viddid >> 16));
1304 
1305 	return 0;
1306 }
1307 
1308 /*
1309  * idt_create_sysfs_files() - create sysfs attribute files
1310  * @pdev:	Pointer to the driver data
1311  * Return status of operation
1312  */
1313 static int idt_create_sysfs_files(struct idt_89hpesx_dev *pdev)
1314 {
1315 	struct device *dev = &pdev->client->dev;
1316 	int ret;
1317 
1318 	/* Don't do anything if EEPROM isn't accessible */
1319 	if (pdev->eesize == 0) {
1320 		dev_dbg(dev, "Skip creating sysfs-files");
1321 		return 0;
1322 	}
1323 
1324 	/* Allocate memory for attribute file */
1325 	pdev->ee_file = devm_kmalloc(dev, sizeof(*pdev->ee_file), GFP_KERNEL);
1326 	if (!pdev->ee_file)
1327 		return -ENOMEM;
1328 
1329 	/* Copy the declared EEPROM attr structure to change some of fields */
1330 	memcpy(pdev->ee_file, &bin_attr_eeprom, sizeof(*pdev->ee_file));
1331 
1332 	/* In case of read-only EEPROM get rid of write ability */
1333 	if (pdev->eero) {
1334 		pdev->ee_file->attr.mode &= ~0200;
1335 		pdev->ee_file->write = NULL;
1336 	}
1337 	/* Create EEPROM sysfs file */
1338 	pdev->ee_file->size = pdev->eesize;
1339 	ret = sysfs_create_bin_file(&dev->kobj, pdev->ee_file);
1340 	if (ret != 0) {
1341 		dev_err(dev, "Failed to create EEPROM sysfs-node");
1342 		return ret;
1343 	}
1344 
1345 	return 0;
1346 }
1347 
1348 /*
1349  * idt_remove_sysfs_files() - remove sysfs attribute files
1350  * @pdev:	Pointer to the driver data
1351  */
1352 static void idt_remove_sysfs_files(struct idt_89hpesx_dev *pdev)
1353 {
1354 	struct device *dev = &pdev->client->dev;
1355 
1356 	/* Don't do anything if EEPROM wasn't accessible */
1357 	if (pdev->eesize == 0)
1358 		return;
1359 
1360 	/* Remove EEPROM sysfs file */
1361 	sysfs_remove_bin_file(&dev->kobj, pdev->ee_file);
1362 }
1363 
1364 /*
1365  * idt_create_dbgfs_files() - create debugfs files
1366  * @pdev:	Pointer to the driver data
1367  */
1368 #define CSRNAME_LEN	((size_t)32)
1369 static void idt_create_dbgfs_files(struct idt_89hpesx_dev *pdev)
1370 {
1371 	struct i2c_client *cli = pdev->client;
1372 	char fname[CSRNAME_LEN];
1373 
1374 	/* Create Debugfs directory for CSR file */
1375 	snprintf(fname, CSRNAME_LEN, "%d-%04hx", cli->adapter->nr, cli->addr);
1376 	pdev->csr_dir = debugfs_create_dir(fname, csr_dbgdir);
1377 
1378 	/* Create Debugfs file for CSR read/write operations */
1379 	debugfs_create_file(cli->name, 0600, pdev->csr_dir, pdev,
1380 			    &csr_dbgfs_ops);
1381 }
1382 
1383 /*
1384  * idt_remove_dbgfs_files() - remove debugfs files
1385  * @pdev:	Pointer to the driver data
1386  */
1387 static void idt_remove_dbgfs_files(struct idt_89hpesx_dev *pdev)
1388 {
1389 	/* Remove CSR directory and it sysfs-node */
1390 	debugfs_remove_recursive(pdev->csr_dir);
1391 }
1392 
1393 /*
1394  * idt_probe() - IDT 89HPESx driver probe() callback method
1395  */
1396 static int idt_probe(struct i2c_client *client, const struct i2c_device_id *id)
1397 {
1398 	struct idt_89hpesx_dev *pdev;
1399 	int ret;
1400 
1401 	/* Create driver data */
1402 	pdev = idt_create_pdev(client);
1403 	if (IS_ERR(pdev))
1404 		return PTR_ERR(pdev);
1405 
1406 	/* Set SMBus operations */
1407 	ret = idt_set_smbus_ops(pdev);
1408 	if (ret != 0)
1409 		goto err_free_pdev;
1410 
1411 	/* Check whether it is truly IDT 89HPESx device */
1412 	ret = idt_check_dev(pdev);
1413 	if (ret != 0)
1414 		goto err_free_pdev;
1415 
1416 	/* Create sysfs files */
1417 	ret = idt_create_sysfs_files(pdev);
1418 	if (ret != 0)
1419 		goto err_free_pdev;
1420 
1421 	/* Create debugfs files */
1422 	idt_create_dbgfs_files(pdev);
1423 
1424 	return 0;
1425 
1426 err_free_pdev:
1427 	idt_free_pdev(pdev);
1428 
1429 	return ret;
1430 }
1431 
1432 /*
1433  * idt_remove() - IDT 89HPESx driver remove() callback method
1434  */
1435 static int idt_remove(struct i2c_client *client)
1436 {
1437 	struct idt_89hpesx_dev *pdev = i2c_get_clientdata(client);
1438 
1439 	/* Remove debugfs files first */
1440 	idt_remove_dbgfs_files(pdev);
1441 
1442 	/* Remove sysfs files */
1443 	idt_remove_sysfs_files(pdev);
1444 
1445 	/* Discard driver data structure */
1446 	idt_free_pdev(pdev);
1447 
1448 	return 0;
1449 }
1450 
1451 /*
1452  * ee_ids - array of supported EEPROMs
1453  */
1454 static const struct i2c_device_id ee_ids[] = {
1455 	{ "24c32",  4096},
1456 	{ "24c64",  8192},
1457 	{ "24c128", 16384},
1458 	{ "24c256", 32768},
1459 	{ "24c512", 65536},
1460 	{}
1461 };
1462 MODULE_DEVICE_TABLE(i2c, ee_ids);
1463 
1464 /*
1465  * idt_ids - supported IDT 89HPESx devices
1466  */
1467 static const struct i2c_device_id idt_ids[] = {
1468 	{ "89hpes8nt2", 0 },
1469 	{ "89hpes12nt3", 0 },
1470 
1471 	{ "89hpes24nt6ag2", 0 },
1472 	{ "89hpes32nt8ag2", 0 },
1473 	{ "89hpes32nt8bg2", 0 },
1474 	{ "89hpes12nt12g2", 0 },
1475 	{ "89hpes16nt16g2", 0 },
1476 	{ "89hpes24nt24g2", 0 },
1477 	{ "89hpes32nt24ag2", 0 },
1478 	{ "89hpes32nt24bg2", 0 },
1479 
1480 	{ "89hpes12n3", 0 },
1481 	{ "89hpes12n3a", 0 },
1482 	{ "89hpes24n3", 0 },
1483 	{ "89hpes24n3a", 0 },
1484 
1485 	{ "89hpes32h8", 0 },
1486 	{ "89hpes32h8g2", 0 },
1487 	{ "89hpes48h12", 0 },
1488 	{ "89hpes48h12g2", 0 },
1489 	{ "89hpes48h12ag2", 0 },
1490 	{ "89hpes16h16", 0 },
1491 	{ "89hpes22h16", 0 },
1492 	{ "89hpes22h16g2", 0 },
1493 	{ "89hpes34h16", 0 },
1494 	{ "89hpes34h16g2", 0 },
1495 	{ "89hpes64h16", 0 },
1496 	{ "89hpes64h16g2", 0 },
1497 	{ "89hpes64h16ag2", 0 },
1498 
1499 	/* { "89hpes3t3", 0 }, // No SMBus-slave iface */
1500 	{ "89hpes12t3g2", 0 },
1501 	{ "89hpes24t3g2", 0 },
1502 	/* { "89hpes4t4", 0 }, // No SMBus-slave iface */
1503 	{ "89hpes16t4", 0 },
1504 	{ "89hpes4t4g2", 0 },
1505 	{ "89hpes10t4g2", 0 },
1506 	{ "89hpes16t4g2", 0 },
1507 	{ "89hpes16t4ag2", 0 },
1508 	{ "89hpes5t5", 0 },
1509 	{ "89hpes6t5", 0 },
1510 	{ "89hpes8t5", 0 },
1511 	{ "89hpes8t5a", 0 },
1512 	{ "89hpes24t6", 0 },
1513 	{ "89hpes6t6g2", 0 },
1514 	{ "89hpes24t6g2", 0 },
1515 	{ "89hpes16t7", 0 },
1516 	{ "89hpes32t8", 0 },
1517 	{ "89hpes32t8g2", 0 },
1518 	{ "89hpes48t12", 0 },
1519 	{ "89hpes48t12g2", 0 },
1520 	{ /* END OF LIST */ }
1521 };
1522 MODULE_DEVICE_TABLE(i2c, idt_ids);
1523 
1524 static const struct of_device_id idt_of_match[] = {
1525 	{ .compatible = "idt,89hpes8nt2", },
1526 	{ .compatible = "idt,89hpes12nt3", },
1527 
1528 	{ .compatible = "idt,89hpes24nt6ag2", },
1529 	{ .compatible = "idt,89hpes32nt8ag2", },
1530 	{ .compatible = "idt,89hpes32nt8bg2", },
1531 	{ .compatible = "idt,89hpes12nt12g2", },
1532 	{ .compatible = "idt,89hpes16nt16g2", },
1533 	{ .compatible = "idt,89hpes24nt24g2", },
1534 	{ .compatible = "idt,89hpes32nt24ag2", },
1535 	{ .compatible = "idt,89hpes32nt24bg2", },
1536 
1537 	{ .compatible = "idt,89hpes12n3", },
1538 	{ .compatible = "idt,89hpes12n3a", },
1539 	{ .compatible = "idt,89hpes24n3", },
1540 	{ .compatible = "idt,89hpes24n3a", },
1541 
1542 	{ .compatible = "idt,89hpes32h8", },
1543 	{ .compatible = "idt,89hpes32h8g2", },
1544 	{ .compatible = "idt,89hpes48h12", },
1545 	{ .compatible = "idt,89hpes48h12g2", },
1546 	{ .compatible = "idt,89hpes48h12ag2", },
1547 	{ .compatible = "idt,89hpes16h16", },
1548 	{ .compatible = "idt,89hpes22h16", },
1549 	{ .compatible = "idt,89hpes22h16g2", },
1550 	{ .compatible = "idt,89hpes34h16", },
1551 	{ .compatible = "idt,89hpes34h16g2", },
1552 	{ .compatible = "idt,89hpes64h16", },
1553 	{ .compatible = "idt,89hpes64h16g2", },
1554 	{ .compatible = "idt,89hpes64h16ag2", },
1555 
1556 	{ .compatible = "idt,89hpes12t3g2", },
1557 	{ .compatible = "idt,89hpes24t3g2", },
1558 
1559 	{ .compatible = "idt,89hpes16t4", },
1560 	{ .compatible = "idt,89hpes4t4g2", },
1561 	{ .compatible = "idt,89hpes10t4g2", },
1562 	{ .compatible = "idt,89hpes16t4g2", },
1563 	{ .compatible = "idt,89hpes16t4ag2", },
1564 	{ .compatible = "idt,89hpes5t5", },
1565 	{ .compatible = "idt,89hpes6t5", },
1566 	{ .compatible = "idt,89hpes8t5", },
1567 	{ .compatible = "idt,89hpes8t5a", },
1568 	{ .compatible = "idt,89hpes24t6", },
1569 	{ .compatible = "idt,89hpes6t6g2", },
1570 	{ .compatible = "idt,89hpes24t6g2", },
1571 	{ .compatible = "idt,89hpes16t7", },
1572 	{ .compatible = "idt,89hpes32t8", },
1573 	{ .compatible = "idt,89hpes32t8g2", },
1574 	{ .compatible = "idt,89hpes48t12", },
1575 	{ .compatible = "idt,89hpes48t12g2", },
1576 	{ },
1577 };
1578 MODULE_DEVICE_TABLE(of, idt_of_match);
1579 
1580 /*
1581  * idt_driver - IDT 89HPESx driver structure
1582  */
1583 static struct i2c_driver idt_driver = {
1584 	.driver = {
1585 		.name = IDT_NAME,
1586 		.of_match_table = idt_of_match,
1587 	},
1588 	.probe = idt_probe,
1589 	.remove = idt_remove,
1590 	.id_table = idt_ids,
1591 };
1592 
1593 /*
1594  * idt_init() - IDT 89HPESx driver init() callback method
1595  */
1596 static int __init idt_init(void)
1597 {
1598 	/* Create Debugfs directory first */
1599 	if (debugfs_initialized())
1600 		csr_dbgdir = debugfs_create_dir("idt_csr", NULL);
1601 
1602 	/* Add new i2c-device driver */
1603 	return i2c_add_driver(&idt_driver);
1604 }
1605 module_init(idt_init);
1606 
1607 /*
1608  * idt_exit() - IDT 89HPESx driver exit() callback method
1609  */
1610 static void __exit idt_exit(void)
1611 {
1612 	/* Discard debugfs directory and all files if any */
1613 	debugfs_remove_recursive(csr_dbgdir);
1614 
1615 	/* Unregister i2c-device driver */
1616 	i2c_del_driver(&idt_driver);
1617 }
1618 module_exit(idt_exit);
1619