1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for the Diolan DLN-2 USB-SPI adapter
4 *
5 * Copyright (c) 2014 Intel Corporation
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/mfd/dln2.h>
12 #include <linux/spi/spi.h>
13 #include <linux/pm_runtime.h>
14 #include <asm/unaligned.h>
15
16 #define DLN2_SPI_MODULE_ID 0x02
17 #define DLN2_SPI_CMD(cmd) DLN2_CMD(cmd, DLN2_SPI_MODULE_ID)
18
19 /* SPI commands */
20 #define DLN2_SPI_GET_PORT_COUNT DLN2_SPI_CMD(0x00)
21 #define DLN2_SPI_ENABLE DLN2_SPI_CMD(0x11)
22 #define DLN2_SPI_DISABLE DLN2_SPI_CMD(0x12)
23 #define DLN2_SPI_IS_ENABLED DLN2_SPI_CMD(0x13)
24 #define DLN2_SPI_SET_MODE DLN2_SPI_CMD(0x14)
25 #define DLN2_SPI_GET_MODE DLN2_SPI_CMD(0x15)
26 #define DLN2_SPI_SET_FRAME_SIZE DLN2_SPI_CMD(0x16)
27 #define DLN2_SPI_GET_FRAME_SIZE DLN2_SPI_CMD(0x17)
28 #define DLN2_SPI_SET_FREQUENCY DLN2_SPI_CMD(0x18)
29 #define DLN2_SPI_GET_FREQUENCY DLN2_SPI_CMD(0x19)
30 #define DLN2_SPI_READ_WRITE DLN2_SPI_CMD(0x1A)
31 #define DLN2_SPI_READ DLN2_SPI_CMD(0x1B)
32 #define DLN2_SPI_WRITE DLN2_SPI_CMD(0x1C)
33 #define DLN2_SPI_SET_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x20)
34 #define DLN2_SPI_GET_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x21)
35 #define DLN2_SPI_SET_DELAY_AFTER_SS DLN2_SPI_CMD(0x22)
36 #define DLN2_SPI_GET_DELAY_AFTER_SS DLN2_SPI_CMD(0x23)
37 #define DLN2_SPI_SET_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x24)
38 #define DLN2_SPI_GET_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x25)
39 #define DLN2_SPI_SET_SS DLN2_SPI_CMD(0x26)
40 #define DLN2_SPI_GET_SS DLN2_SPI_CMD(0x27)
41 #define DLN2_SPI_RELEASE_SS DLN2_SPI_CMD(0x28)
42 #define DLN2_SPI_SS_VARIABLE_ENABLE DLN2_SPI_CMD(0x2B)
43 #define DLN2_SPI_SS_VARIABLE_DISABLE DLN2_SPI_CMD(0x2C)
44 #define DLN2_SPI_SS_VARIABLE_IS_ENABLED DLN2_SPI_CMD(0x2D)
45 #define DLN2_SPI_SS_AAT_ENABLE DLN2_SPI_CMD(0x2E)
46 #define DLN2_SPI_SS_AAT_DISABLE DLN2_SPI_CMD(0x2F)
47 #define DLN2_SPI_SS_AAT_IS_ENABLED DLN2_SPI_CMD(0x30)
48 #define DLN2_SPI_SS_BETWEEN_FRAMES_ENABLE DLN2_SPI_CMD(0x31)
49 #define DLN2_SPI_SS_BETWEEN_FRAMES_DISABLE DLN2_SPI_CMD(0x32)
50 #define DLN2_SPI_SS_BETWEEN_FRAMES_IS_ENABLED DLN2_SPI_CMD(0x33)
51 #define DLN2_SPI_SET_CPHA DLN2_SPI_CMD(0x34)
52 #define DLN2_SPI_GET_CPHA DLN2_SPI_CMD(0x35)
53 #define DLN2_SPI_SET_CPOL DLN2_SPI_CMD(0x36)
54 #define DLN2_SPI_GET_CPOL DLN2_SPI_CMD(0x37)
55 #define DLN2_SPI_SS_MULTI_ENABLE DLN2_SPI_CMD(0x38)
56 #define DLN2_SPI_SS_MULTI_DISABLE DLN2_SPI_CMD(0x39)
57 #define DLN2_SPI_SS_MULTI_IS_ENABLED DLN2_SPI_CMD(0x3A)
58 #define DLN2_SPI_GET_SUPPORTED_MODES DLN2_SPI_CMD(0x40)
59 #define DLN2_SPI_GET_SUPPORTED_CPHA_VALUES DLN2_SPI_CMD(0x41)
60 #define DLN2_SPI_GET_SUPPORTED_CPOL_VALUES DLN2_SPI_CMD(0x42)
61 #define DLN2_SPI_GET_SUPPORTED_FRAME_SIZES DLN2_SPI_CMD(0x43)
62 #define DLN2_SPI_GET_SS_COUNT DLN2_SPI_CMD(0x44)
63 #define DLN2_SPI_GET_MIN_FREQUENCY DLN2_SPI_CMD(0x45)
64 #define DLN2_SPI_GET_MAX_FREQUENCY DLN2_SPI_CMD(0x46)
65 #define DLN2_SPI_GET_MIN_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x47)
66 #define DLN2_SPI_GET_MAX_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x48)
67 #define DLN2_SPI_GET_MIN_DELAY_AFTER_SS DLN2_SPI_CMD(0x49)
68 #define DLN2_SPI_GET_MAX_DELAY_AFTER_SS DLN2_SPI_CMD(0x4A)
69 #define DLN2_SPI_GET_MIN_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x4B)
70 #define DLN2_SPI_GET_MAX_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x4C)
71
72 #define DLN2_SPI_MAX_XFER_SIZE 256
73 #define DLN2_SPI_BUF_SIZE (DLN2_SPI_MAX_XFER_SIZE + 16)
74 #define DLN2_SPI_ATTR_LEAVE_SS_LOW BIT(0)
75 #define DLN2_TRANSFERS_WAIT_COMPLETE 1
76 #define DLN2_TRANSFERS_CANCEL 0
77 #define DLN2_RPM_AUTOSUSPEND_TIMEOUT 2000
78
79 struct dln2_spi {
80 struct platform_device *pdev;
81 struct spi_master *master;
82 u8 port;
83
84 /*
85 * This buffer will be used mainly for read/write operations. Since
86 * they're quite large, we cannot use the stack. Protection is not
87 * needed because all SPI communication is serialized by the SPI core.
88 */
89 void *buf;
90
91 u8 bpw;
92 u32 speed;
93 u16 mode;
94 u8 cs;
95 };
96
97 /*
98 * Enable/Disable SPI module. The disable command will wait for transfers to
99 * complete first.
100 */
dln2_spi_enable(struct dln2_spi * dln2,bool enable)101 static int dln2_spi_enable(struct dln2_spi *dln2, bool enable)
102 {
103 u16 cmd;
104 struct {
105 u8 port;
106 u8 wait_for_completion;
107 } tx;
108 unsigned len = sizeof(tx);
109
110 tx.port = dln2->port;
111
112 if (enable) {
113 cmd = DLN2_SPI_ENABLE;
114 len -= sizeof(tx.wait_for_completion);
115 } else {
116 tx.wait_for_completion = DLN2_TRANSFERS_WAIT_COMPLETE;
117 cmd = DLN2_SPI_DISABLE;
118 }
119
120 return dln2_transfer_tx(dln2->pdev, cmd, &tx, len);
121 }
122
123 /*
124 * Select/unselect multiple CS lines. The selected lines will be automatically
125 * toggled LOW/HIGH by the board firmware during transfers, provided they're
126 * enabled first.
127 *
128 * Ex: cs_mask = 0x03 -> CS0 & CS1 will be selected and the next WR/RD operation
129 * will toggle the lines LOW/HIGH automatically.
130 */
dln2_spi_cs_set(struct dln2_spi * dln2,u8 cs_mask)131 static int dln2_spi_cs_set(struct dln2_spi *dln2, u8 cs_mask)
132 {
133 struct {
134 u8 port;
135 u8 cs;
136 } tx;
137
138 tx.port = dln2->port;
139
140 /*
141 * According to Diolan docs, "a slave device can be selected by changing
142 * the corresponding bit value to 0". The rest must be set to 1. Hence
143 * the bitwise NOT in front.
144 */
145 tx.cs = ~cs_mask;
146
147 return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_SS, &tx, sizeof(tx));
148 }
149
150 /*
151 * Select one CS line. The other lines will be un-selected.
152 */
dln2_spi_cs_set_one(struct dln2_spi * dln2,u8 cs)153 static int dln2_spi_cs_set_one(struct dln2_spi *dln2, u8 cs)
154 {
155 return dln2_spi_cs_set(dln2, BIT(cs));
156 }
157
158 /*
159 * Enable/disable CS lines for usage. The module has to be disabled first.
160 */
dln2_spi_cs_enable(struct dln2_spi * dln2,u8 cs_mask,bool enable)161 static int dln2_spi_cs_enable(struct dln2_spi *dln2, u8 cs_mask, bool enable)
162 {
163 struct {
164 u8 port;
165 u8 cs;
166 } tx;
167 u16 cmd;
168
169 tx.port = dln2->port;
170 tx.cs = cs_mask;
171 cmd = enable ? DLN2_SPI_SS_MULTI_ENABLE : DLN2_SPI_SS_MULTI_DISABLE;
172
173 return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
174 }
175
dln2_spi_cs_enable_all(struct dln2_spi * dln2,bool enable)176 static int dln2_spi_cs_enable_all(struct dln2_spi *dln2, bool enable)
177 {
178 u8 cs_mask = GENMASK(dln2->master->num_chipselect - 1, 0);
179
180 return dln2_spi_cs_enable(dln2, cs_mask, enable);
181 }
182
dln2_spi_get_cs_num(struct dln2_spi * dln2,u16 * cs_num)183 static int dln2_spi_get_cs_num(struct dln2_spi *dln2, u16 *cs_num)
184 {
185 int ret;
186 struct {
187 u8 port;
188 } tx;
189 struct {
190 __le16 cs_count;
191 } rx;
192 unsigned rx_len = sizeof(rx);
193
194 tx.port = dln2->port;
195 ret = dln2_transfer(dln2->pdev, DLN2_SPI_GET_SS_COUNT, &tx, sizeof(tx),
196 &rx, &rx_len);
197 if (ret < 0)
198 return ret;
199 if (rx_len < sizeof(rx))
200 return -EPROTO;
201
202 *cs_num = le16_to_cpu(rx.cs_count);
203
204 dev_dbg(&dln2->pdev->dev, "cs_num = %d\n", *cs_num);
205
206 return 0;
207 }
208
dln2_spi_get_speed(struct dln2_spi * dln2,u16 cmd,u32 * freq)209 static int dln2_spi_get_speed(struct dln2_spi *dln2, u16 cmd, u32 *freq)
210 {
211 int ret;
212 struct {
213 u8 port;
214 } tx;
215 struct {
216 __le32 speed;
217 } rx;
218 unsigned rx_len = sizeof(rx);
219
220 tx.port = dln2->port;
221
222 ret = dln2_transfer(dln2->pdev, cmd, &tx, sizeof(tx), &rx, &rx_len);
223 if (ret < 0)
224 return ret;
225 if (rx_len < sizeof(rx))
226 return -EPROTO;
227
228 *freq = le32_to_cpu(rx.speed);
229
230 return 0;
231 }
232
233 /*
234 * Get bus min/max frequencies.
235 */
dln2_spi_get_speed_range(struct dln2_spi * dln2,u32 * fmin,u32 * fmax)236 static int dln2_spi_get_speed_range(struct dln2_spi *dln2, u32 *fmin, u32 *fmax)
237 {
238 int ret;
239
240 ret = dln2_spi_get_speed(dln2, DLN2_SPI_GET_MIN_FREQUENCY, fmin);
241 if (ret < 0)
242 return ret;
243
244 ret = dln2_spi_get_speed(dln2, DLN2_SPI_GET_MAX_FREQUENCY, fmax);
245 if (ret < 0)
246 return ret;
247
248 dev_dbg(&dln2->pdev->dev, "freq_min = %d, freq_max = %d\n",
249 *fmin, *fmax);
250
251 return 0;
252 }
253
254 /*
255 * Set the bus speed. The module will automatically round down to the closest
256 * available frequency and returns it. The module has to be disabled first.
257 */
dln2_spi_set_speed(struct dln2_spi * dln2,u32 speed)258 static int dln2_spi_set_speed(struct dln2_spi *dln2, u32 speed)
259 {
260 int ret;
261 struct {
262 u8 port;
263 __le32 speed;
264 } __packed tx;
265 struct {
266 __le32 speed;
267 } rx;
268 int rx_len = sizeof(rx);
269
270 tx.port = dln2->port;
271 tx.speed = cpu_to_le32(speed);
272
273 ret = dln2_transfer(dln2->pdev, DLN2_SPI_SET_FREQUENCY, &tx, sizeof(tx),
274 &rx, &rx_len);
275 if (ret < 0)
276 return ret;
277 if (rx_len < sizeof(rx))
278 return -EPROTO;
279
280 return 0;
281 }
282
283 /*
284 * Change CPOL & CPHA. The module has to be disabled first.
285 */
dln2_spi_set_mode(struct dln2_spi * dln2,u8 mode)286 static int dln2_spi_set_mode(struct dln2_spi *dln2, u8 mode)
287 {
288 struct {
289 u8 port;
290 u8 mode;
291 } tx;
292
293 tx.port = dln2->port;
294 tx.mode = mode;
295
296 return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_MODE, &tx, sizeof(tx));
297 }
298
299 /*
300 * Change frame size. The module has to be disabled first.
301 */
dln2_spi_set_bpw(struct dln2_spi * dln2,u8 bpw)302 static int dln2_spi_set_bpw(struct dln2_spi *dln2, u8 bpw)
303 {
304 struct {
305 u8 port;
306 u8 bpw;
307 } tx;
308
309 tx.port = dln2->port;
310 tx.bpw = bpw;
311
312 return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_FRAME_SIZE,
313 &tx, sizeof(tx));
314 }
315
dln2_spi_get_supported_frame_sizes(struct dln2_spi * dln2,u32 * bpw_mask)316 static int dln2_spi_get_supported_frame_sizes(struct dln2_spi *dln2,
317 u32 *bpw_mask)
318 {
319 int ret;
320 struct {
321 u8 port;
322 } tx;
323 struct {
324 u8 count;
325 u8 frame_sizes[36];
326 } *rx = dln2->buf;
327 unsigned rx_len = sizeof(*rx);
328 int i;
329
330 tx.port = dln2->port;
331
332 ret = dln2_transfer(dln2->pdev, DLN2_SPI_GET_SUPPORTED_FRAME_SIZES,
333 &tx, sizeof(tx), rx, &rx_len);
334 if (ret < 0)
335 return ret;
336 if (rx_len < sizeof(*rx))
337 return -EPROTO;
338 if (rx->count > ARRAY_SIZE(rx->frame_sizes))
339 return -EPROTO;
340
341 *bpw_mask = 0;
342 for (i = 0; i < rx->count; i++)
343 *bpw_mask |= BIT(rx->frame_sizes[i] - 1);
344
345 dev_dbg(&dln2->pdev->dev, "bpw_mask = 0x%X\n", *bpw_mask);
346
347 return 0;
348 }
349
350 /*
351 * Copy the data to DLN2 buffer and change the byte order to LE, requested by
352 * DLN2 module. SPI core makes sure that the data length is a multiple of word
353 * size.
354 */
dln2_spi_copy_to_buf(u8 * dln2_buf,const u8 * src,u16 len,u8 bpw)355 static int dln2_spi_copy_to_buf(u8 *dln2_buf, const u8 *src, u16 len, u8 bpw)
356 {
357 #ifdef __LITTLE_ENDIAN
358 memcpy(dln2_buf, src, len);
359 #else
360 if (bpw <= 8) {
361 memcpy(dln2_buf, src, len);
362 } else if (bpw <= 16) {
363 __le16 *d = (__le16 *)dln2_buf;
364 u16 *s = (u16 *)src;
365
366 len = len / 2;
367 while (len--)
368 *d++ = cpu_to_le16p(s++);
369 } else {
370 __le32 *d = (__le32 *)dln2_buf;
371 u32 *s = (u32 *)src;
372
373 len = len / 4;
374 while (len--)
375 *d++ = cpu_to_le32p(s++);
376 }
377 #endif
378
379 return 0;
380 }
381
382 /*
383 * Copy the data from DLN2 buffer and convert to CPU byte order since the DLN2
384 * buffer is LE ordered. SPI core makes sure that the data length is a multiple
385 * of word size. The RX dln2_buf is 2 byte aligned so, for BE, we have to make
386 * sure we avoid unaligned accesses for 32 bit case.
387 */
dln2_spi_copy_from_buf(u8 * dest,const u8 * dln2_buf,u16 len,u8 bpw)388 static int dln2_spi_copy_from_buf(u8 *dest, const u8 *dln2_buf, u16 len, u8 bpw)
389 {
390 #ifdef __LITTLE_ENDIAN
391 memcpy(dest, dln2_buf, len);
392 #else
393 if (bpw <= 8) {
394 memcpy(dest, dln2_buf, len);
395 } else if (bpw <= 16) {
396 u16 *d = (u16 *)dest;
397 __le16 *s = (__le16 *)dln2_buf;
398
399 len = len / 2;
400 while (len--)
401 *d++ = le16_to_cpup(s++);
402 } else {
403 u32 *d = (u32 *)dest;
404 __le32 *s = (__le32 *)dln2_buf;
405
406 len = len / 4;
407 while (len--)
408 *d++ = get_unaligned_le32(s++);
409 }
410 #endif
411
412 return 0;
413 }
414
415 /*
416 * Perform one write operation.
417 */
dln2_spi_write_one(struct dln2_spi * dln2,const u8 * data,u16 data_len,u8 attr)418 static int dln2_spi_write_one(struct dln2_spi *dln2, const u8 *data,
419 u16 data_len, u8 attr)
420 {
421 struct {
422 u8 port;
423 __le16 size;
424 u8 attr;
425 u8 buf[DLN2_SPI_MAX_XFER_SIZE];
426 } __packed *tx = dln2->buf;
427 unsigned tx_len;
428
429 BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE);
430
431 if (data_len > DLN2_SPI_MAX_XFER_SIZE)
432 return -EINVAL;
433
434 tx->port = dln2->port;
435 tx->size = cpu_to_le16(data_len);
436 tx->attr = attr;
437
438 dln2_spi_copy_to_buf(tx->buf, data, data_len, dln2->bpw);
439
440 tx_len = sizeof(*tx) + data_len - DLN2_SPI_MAX_XFER_SIZE;
441 return dln2_transfer_tx(dln2->pdev, DLN2_SPI_WRITE, tx, tx_len);
442 }
443
444 /*
445 * Perform one read operation.
446 */
dln2_spi_read_one(struct dln2_spi * dln2,u8 * data,u16 data_len,u8 attr)447 static int dln2_spi_read_one(struct dln2_spi *dln2, u8 *data,
448 u16 data_len, u8 attr)
449 {
450 int ret;
451 struct {
452 u8 port;
453 __le16 size;
454 u8 attr;
455 } __packed tx;
456 struct {
457 __le16 size;
458 u8 buf[DLN2_SPI_MAX_XFER_SIZE];
459 } __packed *rx = dln2->buf;
460 unsigned rx_len = sizeof(*rx);
461
462 BUILD_BUG_ON(sizeof(*rx) > DLN2_SPI_BUF_SIZE);
463
464 if (data_len > DLN2_SPI_MAX_XFER_SIZE)
465 return -EINVAL;
466
467 tx.port = dln2->port;
468 tx.size = cpu_to_le16(data_len);
469 tx.attr = attr;
470
471 ret = dln2_transfer(dln2->pdev, DLN2_SPI_READ, &tx, sizeof(tx),
472 rx, &rx_len);
473 if (ret < 0)
474 return ret;
475 if (rx_len < sizeof(rx->size) + data_len)
476 return -EPROTO;
477 if (le16_to_cpu(rx->size) != data_len)
478 return -EPROTO;
479
480 dln2_spi_copy_from_buf(data, rx->buf, data_len, dln2->bpw);
481
482 return 0;
483 }
484
485 /*
486 * Perform one write & read operation.
487 */
dln2_spi_read_write_one(struct dln2_spi * dln2,const u8 * tx_data,u8 * rx_data,u16 data_len,u8 attr)488 static int dln2_spi_read_write_one(struct dln2_spi *dln2, const u8 *tx_data,
489 u8 *rx_data, u16 data_len, u8 attr)
490 {
491 int ret;
492 struct {
493 u8 port;
494 __le16 size;
495 u8 attr;
496 u8 buf[DLN2_SPI_MAX_XFER_SIZE];
497 } __packed *tx;
498 struct {
499 __le16 size;
500 u8 buf[DLN2_SPI_MAX_XFER_SIZE];
501 } __packed *rx;
502 unsigned tx_len, rx_len;
503
504 BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE ||
505 sizeof(*rx) > DLN2_SPI_BUF_SIZE);
506
507 if (data_len > DLN2_SPI_MAX_XFER_SIZE)
508 return -EINVAL;
509
510 /*
511 * Since this is a pseudo full-duplex communication, we're perfectly
512 * safe to use the same buffer for both tx and rx. When DLN2 sends the
513 * response back, with the rx data, we don't need the tx buffer anymore.
514 */
515 tx = dln2->buf;
516 rx = dln2->buf;
517
518 tx->port = dln2->port;
519 tx->size = cpu_to_le16(data_len);
520 tx->attr = attr;
521
522 dln2_spi_copy_to_buf(tx->buf, tx_data, data_len, dln2->bpw);
523
524 tx_len = sizeof(*tx) + data_len - DLN2_SPI_MAX_XFER_SIZE;
525 rx_len = sizeof(*rx);
526
527 ret = dln2_transfer(dln2->pdev, DLN2_SPI_READ_WRITE, tx, tx_len,
528 rx, &rx_len);
529 if (ret < 0)
530 return ret;
531 if (rx_len < sizeof(rx->size) + data_len)
532 return -EPROTO;
533 if (le16_to_cpu(rx->size) != data_len)
534 return -EPROTO;
535
536 dln2_spi_copy_from_buf(rx_data, rx->buf, data_len, dln2->bpw);
537
538 return 0;
539 }
540
541 /*
542 * Read/Write wrapper. It will automatically split an operation into multiple
543 * single ones due to device buffer constraints.
544 */
dln2_spi_rdwr(struct dln2_spi * dln2,const u8 * tx_data,u8 * rx_data,u16 data_len,u8 attr)545 static int dln2_spi_rdwr(struct dln2_spi *dln2, const u8 *tx_data,
546 u8 *rx_data, u16 data_len, u8 attr)
547 {
548 int ret;
549 u16 len;
550 u8 temp_attr;
551 u16 remaining = data_len;
552 u16 offset;
553
554 do {
555 if (remaining > DLN2_SPI_MAX_XFER_SIZE) {
556 len = DLN2_SPI_MAX_XFER_SIZE;
557 temp_attr = DLN2_SPI_ATTR_LEAVE_SS_LOW;
558 } else {
559 len = remaining;
560 temp_attr = attr;
561 }
562
563 offset = data_len - remaining;
564
565 if (tx_data && rx_data) {
566 ret = dln2_spi_read_write_one(dln2,
567 tx_data + offset,
568 rx_data + offset,
569 len, temp_attr);
570 } else if (tx_data) {
571 ret = dln2_spi_write_one(dln2,
572 tx_data + offset,
573 len, temp_attr);
574 } else if (rx_data) {
575 ret = dln2_spi_read_one(dln2,
576 rx_data + offset,
577 len, temp_attr);
578 } else {
579 return -EINVAL;
580 }
581
582 if (ret < 0)
583 return ret;
584
585 remaining -= len;
586 } while (remaining);
587
588 return 0;
589 }
590
dln2_spi_prepare_message(struct spi_master * master,struct spi_message * message)591 static int dln2_spi_prepare_message(struct spi_master *master,
592 struct spi_message *message)
593 {
594 int ret;
595 struct dln2_spi *dln2 = spi_master_get_devdata(master);
596 struct spi_device *spi = message->spi;
597
598 if (dln2->cs != spi->chip_select) {
599 ret = dln2_spi_cs_set_one(dln2, spi->chip_select);
600 if (ret < 0)
601 return ret;
602
603 dln2->cs = spi->chip_select;
604 }
605
606 return 0;
607 }
608
dln2_spi_transfer_setup(struct dln2_spi * dln2,u32 speed,u8 bpw,u8 mode)609 static int dln2_spi_transfer_setup(struct dln2_spi *dln2, u32 speed,
610 u8 bpw, u8 mode)
611 {
612 int ret;
613 bool bus_setup_change;
614
615 bus_setup_change = dln2->speed != speed || dln2->mode != mode ||
616 dln2->bpw != bpw;
617
618 if (!bus_setup_change)
619 return 0;
620
621 ret = dln2_spi_enable(dln2, false);
622 if (ret < 0)
623 return ret;
624
625 if (dln2->speed != speed) {
626 ret = dln2_spi_set_speed(dln2, speed);
627 if (ret < 0)
628 return ret;
629
630 dln2->speed = speed;
631 }
632
633 if (dln2->mode != mode) {
634 ret = dln2_spi_set_mode(dln2, mode & 0x3);
635 if (ret < 0)
636 return ret;
637
638 dln2->mode = mode;
639 }
640
641 if (dln2->bpw != bpw) {
642 ret = dln2_spi_set_bpw(dln2, bpw);
643 if (ret < 0)
644 return ret;
645
646 dln2->bpw = bpw;
647 }
648
649 return dln2_spi_enable(dln2, true);
650 }
651
dln2_spi_transfer_one(struct spi_master * master,struct spi_device * spi,struct spi_transfer * xfer)652 static int dln2_spi_transfer_one(struct spi_master *master,
653 struct spi_device *spi,
654 struct spi_transfer *xfer)
655 {
656 struct dln2_spi *dln2 = spi_master_get_devdata(master);
657 int status;
658 u8 attr = 0;
659
660 status = dln2_spi_transfer_setup(dln2, xfer->speed_hz,
661 xfer->bits_per_word,
662 spi->mode);
663 if (status < 0) {
664 dev_err(&dln2->pdev->dev, "Cannot setup transfer\n");
665 return status;
666 }
667
668 if (!xfer->cs_change && !spi_transfer_is_last(master, xfer))
669 attr = DLN2_SPI_ATTR_LEAVE_SS_LOW;
670
671 status = dln2_spi_rdwr(dln2, xfer->tx_buf, xfer->rx_buf,
672 xfer->len, attr);
673 if (status < 0)
674 dev_err(&dln2->pdev->dev, "write/read failed!\n");
675
676 return status;
677 }
678
dln2_spi_probe(struct platform_device * pdev)679 static int dln2_spi_probe(struct platform_device *pdev)
680 {
681 struct spi_master *master;
682 struct dln2_spi *dln2;
683 struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
684 struct device *dev = &pdev->dev;
685 int ret;
686
687 master = spi_alloc_master(&pdev->dev, sizeof(*dln2));
688 if (!master)
689 return -ENOMEM;
690
691 platform_set_drvdata(pdev, master);
692
693 dln2 = spi_master_get_devdata(master);
694
695 dln2->buf = devm_kmalloc(&pdev->dev, DLN2_SPI_BUF_SIZE, GFP_KERNEL);
696 if (!dln2->buf) {
697 ret = -ENOMEM;
698 goto exit_free_master;
699 }
700
701 dln2->master = master;
702 dln2->master->dev.of_node = dev->of_node;
703 dln2->pdev = pdev;
704 dln2->port = pdata->port;
705 /* cs/mode can never be 0xff, so the first transfer will set them */
706 dln2->cs = 0xff;
707 dln2->mode = 0xff;
708
709 /* disable SPI module before continuing with the setup */
710 ret = dln2_spi_enable(dln2, false);
711 if (ret < 0) {
712 dev_err(&pdev->dev, "Failed to disable SPI module\n");
713 goto exit_free_master;
714 }
715
716 ret = dln2_spi_get_cs_num(dln2, &master->num_chipselect);
717 if (ret < 0) {
718 dev_err(&pdev->dev, "Failed to get number of CS pins\n");
719 goto exit_free_master;
720 }
721
722 ret = dln2_spi_get_speed_range(dln2,
723 &master->min_speed_hz,
724 &master->max_speed_hz);
725 if (ret < 0) {
726 dev_err(&pdev->dev, "Failed to read bus min/max freqs\n");
727 goto exit_free_master;
728 }
729
730 ret = dln2_spi_get_supported_frame_sizes(dln2,
731 &master->bits_per_word_mask);
732 if (ret < 0) {
733 dev_err(&pdev->dev, "Failed to read supported frame sizes\n");
734 goto exit_free_master;
735 }
736
737 ret = dln2_spi_cs_enable_all(dln2, true);
738 if (ret < 0) {
739 dev_err(&pdev->dev, "Failed to enable CS pins\n");
740 goto exit_free_master;
741 }
742
743 master->bus_num = -1;
744 master->mode_bits = SPI_CPOL | SPI_CPHA;
745 master->prepare_message = dln2_spi_prepare_message;
746 master->transfer_one = dln2_spi_transfer_one;
747 master->auto_runtime_pm = true;
748
749 /* enable SPI module, we're good to go */
750 ret = dln2_spi_enable(dln2, true);
751 if (ret < 0) {
752 dev_err(&pdev->dev, "Failed to enable SPI module\n");
753 goto exit_free_master;
754 }
755
756 pm_runtime_set_autosuspend_delay(&pdev->dev,
757 DLN2_RPM_AUTOSUSPEND_TIMEOUT);
758 pm_runtime_use_autosuspend(&pdev->dev);
759 pm_runtime_set_active(&pdev->dev);
760 pm_runtime_enable(&pdev->dev);
761
762 ret = devm_spi_register_master(&pdev->dev, master);
763 if (ret < 0) {
764 dev_err(&pdev->dev, "Failed to register master\n");
765 goto exit_register;
766 }
767
768 return ret;
769
770 exit_register:
771 pm_runtime_disable(&pdev->dev);
772 pm_runtime_set_suspended(&pdev->dev);
773
774 if (dln2_spi_enable(dln2, false) < 0)
775 dev_err(&pdev->dev, "Failed to disable SPI module\n");
776 exit_free_master:
777 spi_master_put(master);
778
779 return ret;
780 }
781
dln2_spi_remove(struct platform_device * pdev)782 static int dln2_spi_remove(struct platform_device *pdev)
783 {
784 struct spi_master *master = platform_get_drvdata(pdev);
785 struct dln2_spi *dln2 = spi_master_get_devdata(master);
786
787 pm_runtime_disable(&pdev->dev);
788
789 if (dln2_spi_enable(dln2, false) < 0)
790 dev_err(&pdev->dev, "Failed to disable SPI module\n");
791
792 return 0;
793 }
794
795 #ifdef CONFIG_PM_SLEEP
dln2_spi_suspend(struct device * dev)796 static int dln2_spi_suspend(struct device *dev)
797 {
798 int ret;
799 struct spi_master *master = dev_get_drvdata(dev);
800 struct dln2_spi *dln2 = spi_master_get_devdata(master);
801
802 ret = spi_master_suspend(master);
803 if (ret < 0)
804 return ret;
805
806 if (!pm_runtime_suspended(dev)) {
807 ret = dln2_spi_enable(dln2, false);
808 if (ret < 0)
809 return ret;
810 }
811
812 /*
813 * USB power may be cut off during sleep. Resetting the following
814 * parameters will force the board to be set up before first transfer.
815 */
816 dln2->cs = 0xff;
817 dln2->speed = 0;
818 dln2->bpw = 0;
819 dln2->mode = 0xff;
820
821 return 0;
822 }
823
dln2_spi_resume(struct device * dev)824 static int dln2_spi_resume(struct device *dev)
825 {
826 int ret;
827 struct spi_master *master = dev_get_drvdata(dev);
828 struct dln2_spi *dln2 = spi_master_get_devdata(master);
829
830 if (!pm_runtime_suspended(dev)) {
831 ret = dln2_spi_cs_enable_all(dln2, true);
832 if (ret < 0)
833 return ret;
834
835 ret = dln2_spi_enable(dln2, true);
836 if (ret < 0)
837 return ret;
838 }
839
840 return spi_master_resume(master);
841 }
842 #endif /* CONFIG_PM_SLEEP */
843
844 #ifdef CONFIG_PM
dln2_spi_runtime_suspend(struct device * dev)845 static int dln2_spi_runtime_suspend(struct device *dev)
846 {
847 struct spi_master *master = dev_get_drvdata(dev);
848 struct dln2_spi *dln2 = spi_master_get_devdata(master);
849
850 return dln2_spi_enable(dln2, false);
851 }
852
dln2_spi_runtime_resume(struct device * dev)853 static int dln2_spi_runtime_resume(struct device *dev)
854 {
855 struct spi_master *master = dev_get_drvdata(dev);
856 struct dln2_spi *dln2 = spi_master_get_devdata(master);
857
858 return dln2_spi_enable(dln2, true);
859 }
860 #endif /* CONFIG_PM */
861
862 static const struct dev_pm_ops dln2_spi_pm = {
863 SET_SYSTEM_SLEEP_PM_OPS(dln2_spi_suspend, dln2_spi_resume)
864 SET_RUNTIME_PM_OPS(dln2_spi_runtime_suspend,
865 dln2_spi_runtime_resume, NULL)
866 };
867
868 static struct platform_driver spi_dln2_driver = {
869 .driver = {
870 .name = "dln2-spi",
871 .pm = &dln2_spi_pm,
872 },
873 .probe = dln2_spi_probe,
874 .remove = dln2_spi_remove,
875 };
876 module_platform_driver(spi_dln2_driver);
877
878 MODULE_DESCRIPTION("Driver for the Diolan DLN2 SPI master interface");
879 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
880 MODULE_LICENSE("GPL v2");
881 MODULE_ALIAS("platform:dln2-spi");
882