1// SPDX-License-Identifier: GPL-2.0
2//
3// Register map access API - SPI AVMM support
4//
5// Copyright (C) 2018-2020 Intel Corporation. All rights reserved.
6
7#include <linux/module.h>
8#include <linux/regmap.h>
9#include <linux/spi/spi.h>
10#include <linux/swab.h>
11
12/*
13 * This driver implements the regmap operations for a generic SPI
14 * master to access the registers of the spi slave chip which has an
15 * Avalone bus in it.
16 *
17 * The "SPI slave to Avalon Master Bridge" (spi-avmm) IP should be integrated
18 * in the spi slave chip. The IP acts as a bridge to convert encoded streams of
19 * bytes from the host to the internal register read/write on Avalon bus. In
20 * order to issue register access requests to the slave chip, the host should
21 * send formatted bytes that conform to the transfer protocol.
22 * The transfer protocol contains 3 layers: transaction layer, packet layer
23 * and physical layer.
24 *
25 * Reference Documents could be found at:
26 * https://www.intel.com/content/www/us/en/programmable/documentation/sfo1400787952932.html
27 *
28 * Chapter "SPI Slave/JTAG to Avalon Master Bridge Cores" is a general
29 * introduction to the protocol.
30 *
31 * Chapter "Avalon Packets to Transactions Converter Core" describes
32 * the transaction layer.
33 *
34 * Chapter "Avalon-ST Bytes to Packets and Packets to Bytes Converter Cores"
35 * describes the packet layer.
36 *
37 * Chapter "Avalon-ST Serial Peripheral Interface Core" describes the
38 * physical layer.
39 *
40 *
41 * When host issues a regmap read/write, the driver will transform the request
42 * to byte stream layer by layer. It formats the register addr, value and
43 * length to the transaction layer request, then converts the request to packet
44 * layer bytes stream and then to physical layer bytes stream. Finally the
45 * driver sends the formatted byte stream over SPI bus to the slave chip.
46 *
47 * The spi-avmm IP on the slave chip decodes the byte stream and initiates
48 * register read/write on its internal Avalon bus, and then encodes the
49 * response to byte stream and sends back to host.
50 *
51 * The driver receives the byte stream, reverses the 3 layers transformation,
52 * and finally gets the response value (read out data for register read,
53 * successful written size for register write).
54 */
55
56#define PKT_SOP 0x7a
57#define PKT_EOP 0x7b
58#define PKT_CHANNEL 0x7c
59#define PKT_ESC 0x7d
60
61#define PHY_IDLE 0x4a
62#define PHY_ESC 0x4d
63
64#define TRANS_CODE_WRITE 0x0
65#define TRANS_CODE_SEQ_WRITE 0x4
66#define TRANS_CODE_READ 0x10
67#define TRANS_CODE_SEQ_READ 0x14
68#define TRANS_CODE_NO_TRANS 0x7f
69
70#define SPI_AVMM_XFER_TIMEOUT (msecs_to_jiffies(200))
71
72/* slave's register addr is 32 bits */
73#define SPI_AVMM_REG_SIZE 4UL
74/* slave's register value is 32 bits */
75#define SPI_AVMM_VAL_SIZE 4UL
76
77/*
78 * max rx size could be larger. But considering the buffer consuming,
79 * it is proper that we limit 1KB xfer at max.
80 */
81#define MAX_READ_CNT 256UL
82#define MAX_WRITE_CNT 1UL
83
84struct trans_req_header {
85 u8 code;
86 u8 rsvd;
87 __be16 size;
88 __be32 addr;
89} __packed;
90
91struct trans_resp_header {
92 u8 r_code;
93 u8 rsvd;
94 __be16 size;
95} __packed;
96
97#define TRANS_REQ_HD_SIZE (sizeof(struct trans_req_header))
98#define TRANS_RESP_HD_SIZE (sizeof(struct trans_resp_header))
99
100/*
101 * In transaction layer,
102 * the write request format is: Transaction request header + data
103 * the read request format is: Transaction request header
104 * the write response format is: Transaction response header
105 * the read response format is: pure data, no Transaction response header
106 */
107#define TRANS_WR_TX_SIZE(n) (TRANS_REQ_HD_SIZE + SPI_AVMM_VAL_SIZE * (n))
108#define TRANS_RD_TX_SIZE TRANS_REQ_HD_SIZE
109#define TRANS_TX_MAX TRANS_WR_TX_SIZE(MAX_WRITE_CNT)
110
111#define TRANS_RD_RX_SIZE(n) (SPI_AVMM_VAL_SIZE * (n))
112#define TRANS_WR_RX_SIZE TRANS_RESP_HD_SIZE
113#define TRANS_RX_MAX TRANS_RD_RX_SIZE(MAX_READ_CNT)
114
115/* tx & rx share one transaction layer buffer */
116#define TRANS_BUF_SIZE ((TRANS_TX_MAX > TRANS_RX_MAX) ? \
117 TRANS_TX_MAX : TRANS_RX_MAX)
118
119/*
120 * In tx phase, the host prepares all the phy layer bytes of a request in the
121 * phy buffer and sends them in a batch.
122 *
123 * The packet layer and physical layer defines several special chars for
124 * various purpose, when a transaction layer byte hits one of these special
125 * chars, it should be escaped. The escape rule is, "Escape char first,
126 * following the byte XOR'ed with 0x20".
127 *
128 * This macro defines the max possible length of the phy data. In the worst
129 * case, all transaction layer bytes need to be escaped (so the data length
130 * doubles), plus 4 special chars (SOP, CHANNEL, CHANNEL_NUM, EOP). Finally
131 * we should make sure the length is aligned to SPI BPW.
132 */
133#define PHY_TX_MAX ALIGN(2 * TRANS_TX_MAX + 4, 4)
134
135/*
136 * Unlike tx, phy rx is affected by possible PHY_IDLE bytes from slave, the max
137 * length of the rx bit stream is unpredictable. So the driver reads the words
138 * one by one, and parses each word immediately into transaction layer buffer.
139 * Only one word length of phy buffer is used for rx.
140 */
141#define PHY_BUF_SIZE PHY_TX_MAX
142
143/**
144 * struct spi_avmm_bridge - SPI slave to AVMM bus master bridge
145 *
146 * @spi: spi slave associated with this bridge.
147 * @word_len: bytes of word for spi transfer.
148 * @trans_len: length of valid data in trans_buf.
149 * @phy_len: length of valid data in phy_buf.
150 * @trans_buf: the bridge buffer for transaction layer data.
151 * @phy_buf: the bridge buffer for physical layer data.
152 * @swap_words: the word swapping cb for phy data. NULL if not needed.
153 *
154 * As a device's registers are implemented on the AVMM bus address space, it
155 * requires the driver to issue formatted requests to spi slave to AVMM bus
156 * master bridge to perform register access.
157 */
158struct spi_avmm_bridge {
159 struct spi_device *spi;
160 unsigned char word_len;
161 unsigned int trans_len;
162 unsigned int phy_len;
163 /* bridge buffer used in translation between protocol layers */
164 char trans_buf[TRANS_BUF_SIZE];
165 char phy_buf[PHY_BUF_SIZE];
166 void (*swap_words)(void *buf, unsigned int len);
167};
168
169static void br_swap_words_32(void *buf, unsigned int len)
170{
171 swab32_array(buf, words: len / 4);
172}
173
174/*
175 * Format transaction layer data in br->trans_buf according to the register
176 * access request, Store valid transaction layer data length in br->trans_len.
177 */
178static int br_trans_tx_prepare(struct spi_avmm_bridge *br, bool is_read, u32 reg,
179 u32 *wr_val, u32 count)
180{
181 struct trans_req_header *header;
182 unsigned int trans_len;
183 u8 code;
184 __le32 *data;
185 int i;
186
187 if (is_read) {
188 if (count == 1)
189 code = TRANS_CODE_READ;
190 else
191 code = TRANS_CODE_SEQ_READ;
192 } else {
193 if (count == 1)
194 code = TRANS_CODE_WRITE;
195 else
196 code = TRANS_CODE_SEQ_WRITE;
197 }
198
199 header = (struct trans_req_header *)br->trans_buf;
200 header->code = code;
201 header->rsvd = 0;
202 header->size = cpu_to_be16((u16)count * SPI_AVMM_VAL_SIZE);
203 header->addr = cpu_to_be32(reg);
204
205 trans_len = TRANS_REQ_HD_SIZE;
206
207 if (!is_read) {
208 trans_len += SPI_AVMM_VAL_SIZE * count;
209 if (trans_len > sizeof(br->trans_buf))
210 return -ENOMEM;
211
212 data = (__le32 *)(br->trans_buf + TRANS_REQ_HD_SIZE);
213
214 for (i = 0; i < count; i++)
215 *data++ = cpu_to_le32(*wr_val++);
216 }
217
218 /* Store valid trans data length for next layer */
219 br->trans_len = trans_len;
220
221 return 0;
222}
223
224/*
225 * Convert transaction layer data (in br->trans_buf) to phy layer data, store
226 * them in br->phy_buf. Pad the phy_buf aligned with SPI's BPW. Store valid phy
227 * layer data length in br->phy_len.
228 *
229 * phy_buf len should be aligned with SPI's BPW. Spare bytes should be padded
230 * with PHY_IDLE, then the slave will just drop them.
231 *
232 * The driver will not simply pad 4a at the tail. The concern is that driver
233 * will not store MISO data during tx phase, if the driver pads 4a at the tail,
234 * it is possible that if the slave is fast enough to response at the padding
235 * time. As a result these rx bytes are lost. In the following case, 7a,7c,00
236 * will lost.
237 * MOSI ...|7a|7c|00|10| |00|00|04|02| |4b|7d|5a|7b| |40|4a|4a|4a| |XX|XX|...
238 * MISO ...|4a|4a|4a|4a| |4a|4a|4a|4a| |4a|4a|4a|4a| |4a|7a|7c|00| |78|56|...
239 *
240 * So the driver moves EOP and bytes after EOP to the end of the aligned size,
241 * then fill the hole with PHY_IDLE. As following:
242 * before pad ...|7a|7c|00|10| |00|00|04|02| |4b|7d|5a|7b| |40|
243 * after pad ...|7a|7c|00|10| |00|00|04|02| |4b|7d|5a|4a| |4a|4a|7b|40|
244 * Then if the slave will not get the entire packet before the tx phase is
245 * over, it can't responsed to anything either.
246 */
247static int br_pkt_phy_tx_prepare(struct spi_avmm_bridge *br)
248{
249 char *tb, *tb_end, *pb, *pb_limit, *pb_eop = NULL;
250 unsigned int aligned_phy_len, move_size;
251 bool need_esc = false;
252
253 tb = br->trans_buf;
254 tb_end = tb + br->trans_len;
255 pb = br->phy_buf;
256 pb_limit = pb + ARRAY_SIZE(br->phy_buf);
257
258 *pb++ = PKT_SOP;
259
260 /*
261 * The driver doesn't support multiple channels so the channel number
262 * is always 0.
263 */
264 *pb++ = PKT_CHANNEL;
265 *pb++ = 0x0;
266
267 for (; pb < pb_limit && tb < tb_end; pb++) {
268 if (need_esc) {
269 *pb = *tb++ ^ 0x20;
270 need_esc = false;
271 continue;
272 }
273
274 /* EOP should be inserted before the last valid char */
275 if (tb == tb_end - 1 && !pb_eop) {
276 *pb = PKT_EOP;
277 pb_eop = pb;
278 continue;
279 }
280
281 /*
282 * insert an ESCAPE char if the data value equals any special
283 * char.
284 */
285 switch (*tb) {
286 case PKT_SOP:
287 case PKT_EOP:
288 case PKT_CHANNEL:
289 case PKT_ESC:
290 *pb = PKT_ESC;
291 need_esc = true;
292 break;
293 case PHY_IDLE:
294 case PHY_ESC:
295 *pb = PHY_ESC;
296 need_esc = true;
297 break;
298 default:
299 *pb = *tb++;
300 break;
301 }
302 }
303
304 /* The phy buffer is used out but transaction layer data remains */
305 if (tb < tb_end)
306 return -ENOMEM;
307
308 /* Store valid phy data length for spi transfer */
309 br->phy_len = pb - br->phy_buf;
310
311 if (br->word_len == 1)
312 return 0;
313
314 /* Do phy buf padding if word_len > 1 byte. */
315 aligned_phy_len = ALIGN(br->phy_len, br->word_len);
316 if (aligned_phy_len > sizeof(br->phy_buf))
317 return -ENOMEM;
318
319 if (aligned_phy_len == br->phy_len)
320 return 0;
321
322 /* move EOP and bytes after EOP to the end of aligned size */
323 move_size = pb - pb_eop;
324 memmove(&br->phy_buf[aligned_phy_len - move_size], pb_eop, move_size);
325
326 /* fill the hole with PHY_IDLEs */
327 memset(pb_eop, PHY_IDLE, aligned_phy_len - br->phy_len);
328
329 /* update the phy data length */
330 br->phy_len = aligned_phy_len;
331
332 return 0;
333}
334
335/*
336 * In tx phase, the slave only returns PHY_IDLE (0x4a). So the driver will
337 * ignore rx in tx phase.
338 */
339static int br_do_tx(struct spi_avmm_bridge *br)
340{
341 /* reorder words for spi transfer */
342 if (br->swap_words)
343 br->swap_words(br->phy_buf, br->phy_len);
344
345 /* send all data in phy_buf */
346 return spi_write(spi: br->spi, buf: br->phy_buf, len: br->phy_len);
347}
348
349/*
350 * This function read the rx byte stream from SPI word by word and convert
351 * them to transaction layer data in br->trans_buf. It also stores the length
352 * of rx transaction layer data in br->trans_len
353 *
354 * The slave may send an unknown number of PHY_IDLEs in rx phase, so we cannot
355 * prepare a fixed length buffer to receive all of the rx data in a batch. We
356 * have to read word by word and convert them to transaction layer data at
357 * once.
358 */
359static int br_do_rx_and_pkt_phy_parse(struct spi_avmm_bridge *br)
360{
361 bool eop_found = false, channel_found = false, esc_found = false;
362 bool valid_word = false, last_try = false;
363 struct device *dev = &br->spi->dev;
364 char *pb, *tb_limit, *tb = NULL;
365 unsigned long poll_timeout;
366 int ret, i;
367
368 tb_limit = br->trans_buf + ARRAY_SIZE(br->trans_buf);
369 pb = br->phy_buf;
370 poll_timeout = jiffies + SPI_AVMM_XFER_TIMEOUT;
371 while (tb < tb_limit) {
372 ret = spi_read(spi: br->spi, buf: pb, len: br->word_len);
373 if (ret)
374 return ret;
375
376 /* reorder the word back */
377 if (br->swap_words)
378 br->swap_words(pb, br->word_len);
379
380 valid_word = false;
381 for (i = 0; i < br->word_len; i++) {
382 /* drop everything before first SOP */
383 if (!tb && pb[i] != PKT_SOP)
384 continue;
385
386 /* drop PHY_IDLE */
387 if (pb[i] == PHY_IDLE)
388 continue;
389
390 valid_word = true;
391
392 /*
393 * We don't support multiple channels, so error out if
394 * a non-zero channel number is found.
395 */
396 if (channel_found) {
397 if (pb[i] != 0) {
398 dev_err(dev, "%s channel num != 0\n",
399 __func__);
400 return -EFAULT;
401 }
402
403 channel_found = false;
404 continue;
405 }
406
407 switch (pb[i]) {
408 case PKT_SOP:
409 /*
410 * reset the parsing if a second SOP appears.
411 */
412 tb = br->trans_buf;
413 eop_found = false;
414 channel_found = false;
415 esc_found = false;
416 break;
417 case PKT_EOP:
418 /*
419 * No special char is expected after ESC char.
420 * No special char (except ESC & PHY_IDLE) is
421 * expected after EOP char.
422 *
423 * The special chars are all dropped.
424 */
425 if (esc_found || eop_found)
426 return -EFAULT;
427
428 eop_found = true;
429 break;
430 case PKT_CHANNEL:
431 if (esc_found || eop_found)
432 return -EFAULT;
433
434 channel_found = true;
435 break;
436 case PKT_ESC:
437 case PHY_ESC:
438 if (esc_found)
439 return -EFAULT;
440
441 esc_found = true;
442 break;
443 default:
444 /* Record the normal byte in trans_buf. */
445 if (esc_found) {
446 *tb++ = pb[i] ^ 0x20;
447 esc_found = false;
448 } else {
449 *tb++ = pb[i];
450 }
451
452 /*
453 * We get the last normal byte after EOP, it is
454 * time we finish. Normally the function should
455 * return here.
456 */
457 if (eop_found) {
458 br->trans_len = tb - br->trans_buf;
459 return 0;
460 }
461 }
462 }
463
464 if (valid_word) {
465 /* update poll timeout when we get valid word */
466 poll_timeout = jiffies + SPI_AVMM_XFER_TIMEOUT;
467 last_try = false;
468 } else {
469 /*
470 * We timeout when rx keeps invalid for some time. But
471 * it is possible we are scheduled out for long time
472 * after a spi_read. So when we are scheduled in, a SW
473 * timeout happens. But actually HW may have worked fine and
474 * has been ready long time ago. So we need to do an extra
475 * read, if we get a valid word then we could continue rx,
476 * otherwise real a HW issue happens.
477 */
478 if (last_try)
479 return -ETIMEDOUT;
480
481 if (time_after(jiffies, poll_timeout))
482 last_try = true;
483 }
484 }
485
486 /*
487 * We have used out all transfer layer buffer but cannot find the end
488 * of the byte stream.
489 */
490 dev_err(dev, "%s transfer buffer is full but rx doesn't end\n",
491 __func__);
492
493 return -EFAULT;
494}
495
496/*
497 * For read transactions, the avmm bus will directly return register values
498 * without transaction response header.
499 */
500static int br_rd_trans_rx_parse(struct spi_avmm_bridge *br,
501 u32 *val, unsigned int expected_count)
502{
503 unsigned int i, trans_len = br->trans_len;
504 __le32 *data;
505
506 if (expected_count * SPI_AVMM_VAL_SIZE != trans_len)
507 return -EFAULT;
508
509 data = (__le32 *)br->trans_buf;
510 for (i = 0; i < expected_count; i++)
511 *val++ = le32_to_cpu(*data++);
512
513 return 0;
514}
515
516/*
517 * For write transactions, the slave will return a transaction response
518 * header.
519 */
520static int br_wr_trans_rx_parse(struct spi_avmm_bridge *br,
521 unsigned int expected_count)
522{
523 unsigned int trans_len = br->trans_len;
524 struct trans_resp_header *resp;
525 u8 code;
526 u16 val_len;
527
528 if (trans_len != TRANS_RESP_HD_SIZE)
529 return -EFAULT;
530
531 resp = (struct trans_resp_header *)br->trans_buf;
532
533 code = resp->r_code ^ 0x80;
534 val_len = be16_to_cpu(resp->size);
535 if (!val_len || val_len != expected_count * SPI_AVMM_VAL_SIZE)
536 return -EFAULT;
537
538 /* error out if the trans code doesn't align with the val size */
539 if ((val_len == SPI_AVMM_VAL_SIZE && code != TRANS_CODE_WRITE) ||
540 (val_len > SPI_AVMM_VAL_SIZE && code != TRANS_CODE_SEQ_WRITE))
541 return -EFAULT;
542
543 return 0;
544}
545
546static int do_reg_access(void *context, bool is_read, unsigned int reg,
547 unsigned int *value, unsigned int count)
548{
549 struct spi_avmm_bridge *br = context;
550 int ret;
551
552 /* invalidate bridge buffers first */
553 br->trans_len = 0;
554 br->phy_len = 0;
555
556 ret = br_trans_tx_prepare(br, is_read, reg, wr_val: value, count);
557 if (ret)
558 return ret;
559
560 ret = br_pkt_phy_tx_prepare(br);
561 if (ret)
562 return ret;
563
564 ret = br_do_tx(br);
565 if (ret)
566 return ret;
567
568 ret = br_do_rx_and_pkt_phy_parse(br);
569 if (ret)
570 return ret;
571
572 if (is_read)
573 return br_rd_trans_rx_parse(br, val: value, expected_count: count);
574 else
575 return br_wr_trans_rx_parse(br, expected_count: count);
576}
577
578static int regmap_spi_avmm_gather_write(void *context,
579 const void *reg_buf, size_t reg_len,
580 const void *val_buf, size_t val_len)
581{
582 if (reg_len != SPI_AVMM_REG_SIZE)
583 return -EINVAL;
584
585 if (!IS_ALIGNED(val_len, SPI_AVMM_VAL_SIZE))
586 return -EINVAL;
587
588 return do_reg_access(context, is_read: false, reg: *(u32 *)reg_buf, value: (u32 *)val_buf,
589 count: val_len / SPI_AVMM_VAL_SIZE);
590}
591
592static int regmap_spi_avmm_write(void *context, const void *data, size_t bytes)
593{
594 if (bytes < SPI_AVMM_REG_SIZE + SPI_AVMM_VAL_SIZE)
595 return -EINVAL;
596
597 return regmap_spi_avmm_gather_write(context, reg_buf: data, SPI_AVMM_REG_SIZE,
598 val_buf: data + SPI_AVMM_REG_SIZE,
599 val_len: bytes - SPI_AVMM_REG_SIZE);
600}
601
602static int regmap_spi_avmm_read(void *context,
603 const void *reg_buf, size_t reg_len,
604 void *val_buf, size_t val_len)
605{
606 if (reg_len != SPI_AVMM_REG_SIZE)
607 return -EINVAL;
608
609 if (!IS_ALIGNED(val_len, SPI_AVMM_VAL_SIZE))
610 return -EINVAL;
611
612 return do_reg_access(context, is_read: true, reg: *(u32 *)reg_buf, value: val_buf,
613 count: (val_len / SPI_AVMM_VAL_SIZE));
614}
615
616static struct spi_avmm_bridge *
617spi_avmm_bridge_ctx_gen(struct spi_device *spi)
618{
619 struct spi_avmm_bridge *br;
620
621 if (!spi)
622 return ERR_PTR(error: -ENODEV);
623
624 /* Only support BPW == 8 or 32 now. Try 32 BPW first. */
625 spi->mode = SPI_MODE_1;
626 spi->bits_per_word = 32;
627 if (spi_setup(spi)) {
628 spi->bits_per_word = 8;
629 if (spi_setup(spi))
630 return ERR_PTR(error: -EINVAL);
631 }
632
633 br = kzalloc(sizeof(*br), GFP_KERNEL);
634 if (!br)
635 return ERR_PTR(error: -ENOMEM);
636
637 br->spi = spi;
638 br->word_len = spi->bits_per_word / 8;
639 if (br->word_len == 4) {
640 /*
641 * The protocol requires little endian byte order but MSB
642 * first. So driver needs to swap the byte order word by word
643 * if word length > 1.
644 */
645 br->swap_words = br_swap_words_32;
646 }
647
648 return br;
649}
650
651static void spi_avmm_bridge_ctx_free(void *context)
652{
653 kfree(objp: context);
654}
655
656static const struct regmap_bus regmap_spi_avmm_bus = {
657 .write = regmap_spi_avmm_write,
658 .gather_write = regmap_spi_avmm_gather_write,
659 .read = regmap_spi_avmm_read,
660 .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
661 .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
662 .max_raw_read = SPI_AVMM_VAL_SIZE * MAX_READ_CNT,
663 .max_raw_write = SPI_AVMM_VAL_SIZE * MAX_WRITE_CNT,
664 .free_context = spi_avmm_bridge_ctx_free,
665};
666
667struct regmap *__regmap_init_spi_avmm(struct spi_device *spi,
668 const struct regmap_config *config,
669 struct lock_class_key *lock_key,
670 const char *lock_name)
671{
672 struct spi_avmm_bridge *bridge;
673 struct regmap *map;
674
675 bridge = spi_avmm_bridge_ctx_gen(spi);
676 if (IS_ERR(ptr: bridge))
677 return ERR_CAST(ptr: bridge);
678
679 map = __regmap_init(dev: &spi->dev, bus: &regmap_spi_avmm_bus,
680 bus_context: bridge, config, lock_key, lock_name);
681 if (IS_ERR(ptr: map)) {
682 spi_avmm_bridge_ctx_free(context: bridge);
683 return ERR_CAST(ptr: map);
684 }
685
686 return map;
687}
688EXPORT_SYMBOL_GPL(__regmap_init_spi_avmm);
689
690struct regmap *__devm_regmap_init_spi_avmm(struct spi_device *spi,
691 const struct regmap_config *config,
692 struct lock_class_key *lock_key,
693 const char *lock_name)
694{
695 struct spi_avmm_bridge *bridge;
696 struct regmap *map;
697
698 bridge = spi_avmm_bridge_ctx_gen(spi);
699 if (IS_ERR(ptr: bridge))
700 return ERR_CAST(ptr: bridge);
701
702 map = __devm_regmap_init(dev: &spi->dev, bus: &regmap_spi_avmm_bus,
703 bus_context: bridge, config, lock_key, lock_name);
704 if (IS_ERR(ptr: map)) {
705 spi_avmm_bridge_ctx_free(context: bridge);
706 return ERR_CAST(ptr: map);
707 }
708
709 return map;
710}
711EXPORT_SYMBOL_GPL(__devm_regmap_init_spi_avmm);
712
713MODULE_DESCRIPTION("Register map access API - SPI AVMM support");
714MODULE_LICENSE("GPL v2");
715

source code of linux/drivers/base/regmap/regmap-spi-avmm.c