1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Common SPI Interface: Controller-specific definitions
4 *
5 * (C) Copyright 2001
6 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
7 */
8
9 #ifndef _SPI_H_
10 #define _SPI_H_
11
12 #include <linux/bitops.h>
13
14 struct spinand_info;
15
16 /* SPI mode flags */
17 #define SPI_CPHA BIT(0) /* clock phase (1 = SPI_CLOCK_PHASE_SECOND) */
18 #define SPI_CPOL BIT(1) /* clock polarity (1 = SPI_POLARITY_HIGH) */
19 #define SPI_MODE_0 (0|0) /* (original MicroWire) */
20 #define SPI_MODE_1 (0|SPI_CPHA)
21 #define SPI_MODE_2 (SPI_CPOL|0)
22 #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
23 #define SPI_CS_HIGH BIT(2) /* CS active high */
24 #define SPI_LSB_FIRST BIT(3) /* per-word bits-on-wire */
25 #define SPI_3WIRE BIT(4) /* SI/SO signals shared */
26 #define SPI_LOOP BIT(5) /* loopback mode */
27 #define SPI_SLAVE BIT(6) /* slave mode */
28 #define SPI_PREAMBLE BIT(7) /* Skip preamble bytes */
29 #define SPI_TX_BYTE BIT(8) /* transmit with 1 wire byte */
30 #define SPI_TX_DUAL BIT(9) /* transmit with 2 wires */
31 #define SPI_TX_QUAD BIT(10) /* transmit with 4 wires */
32 #define SPI_RX_SLOW BIT(11) /* receive with 1 wire slow */
33 #define SPI_RX_DUAL BIT(12) /* receive with 2 wires */
34 #define SPI_RX_QUAD BIT(13) /* receive with 4 wires */
35 #define SPI_TX_OCTAL BIT(14) /* transmit with 8 wires */
36 #define SPI_RX_OCTAL BIT(15) /* receive with 8 wires */
37
38 /* Header byte that marks the start of the message */
39 #define SPI_PREAMBLE_END_BYTE 0xec
40
41 #define SPI_DEFAULT_WORDLEN 8
42
43 #define SPI_3BYTE_MODE 0x0
44 #define SPI_4BYTE_MODE 0x1
45
46 /* Max no. of CS supported per spi device */
47 #define SPI_CS_CNT_MAX 2
48
49 /**
50 * struct dm_spi_bus - SPI bus info
51 *
52 * This contains information about a SPI bus. To obtain this structure, use
53 * dev_get_uclass_priv(bus) where bus is the SPI bus udevice.
54 *
55 * @max_hz: Maximum speed that the bus can tolerate.
56 * @speed: Current bus speed. This is 0 until the bus is first claimed.
57 * @mode: Current bus mode. This is 0 until the bus is first claimed.
58 *
59 * TODO(sjg@chromium.org): Remove this and use max_hz from struct spi_slave.
60 */
61 struct dm_spi_bus {
62 uint max_hz;
63 uint speed;
64 uint mode;
65 };
66
67 /**
68 * struct dm_spi_plat - platform data for all SPI slaves
69 *
70 * This describes a SPI slave, a child device of the SPI bus. To obtain this
71 * struct from a spi_slave, use dev_get_parent_plat(dev) or
72 * dev_get_parent_plat(slave->dev).
73 *
74 * This data is immutable. Each time the device is probed, @max_hz and @mode
75 * will be copied to struct spi_slave.
76 *
77 * @cs: Chip select number (0..n-1)
78 * @max_hz: Maximum bus speed that this slave can tolerate
79 * @mode: SPI mode to use for this device (see SPI mode flags)
80 */
81 struct dm_spi_slave_plat {
82 unsigned int cs[SPI_CS_CNT_MAX];
83 uint max_hz;
84 uint mode;
85 };
86
87 /**
88 * enum spi_clock_phase - indicates the clock phase to use for SPI (CPHA)
89 *
90 * @SPI_CLOCK_PHASE_FIRST: Data sampled on the first phase
91 * @SPI_CLOCK_PHASE_SECOND: Data sampled on the second phase
92 */
93 enum spi_clock_phase {
94 SPI_CLOCK_PHASE_FIRST,
95 SPI_CLOCK_PHASE_SECOND,
96 };
97
98 /**
99 * enum spi_wire_mode - indicates the number of wires used for SPI
100 *
101 * @SPI_4_WIRE_MODE: Normal bidirectional mode with MOSI and MISO
102 * @SPI_3_WIRE_MODE: Unidirectional version with a single data line SISO
103 */
104 enum spi_wire_mode {
105 SPI_4_WIRE_MODE,
106 SPI_3_WIRE_MODE,
107 };
108
109 /**
110 * enum spi_polarity - indicates the polarity of the SPI bus (CPOL)
111 *
112 * @SPI_POLARITY_LOW: Clock is low in idle state
113 * @SPI_POLARITY_HIGH: Clock is high in idle state
114 */
115 enum spi_polarity {
116 SPI_POLARITY_LOW,
117 SPI_POLARITY_HIGH,
118 };
119
120 /**
121 * struct spi_slave - Representation of a SPI slave
122 *
123 * For driver model this is the per-child data used by the SPI bus. It can
124 * be accessed using dev_get_parent_priv() on the slave device. The SPI uclass
125 * sets up per_child_auto to sizeof(struct spi_slave), and the
126 * driver should not override it. Two platform data fields (max_hz and mode)
127 * are copied into this structure to provide an initial value. This allows
128 * them to be changed, since we should never change platform data in drivers.
129 *
130 * If not using driver model, drivers are expected to extend this with
131 * controller-specific data.
132 *
133 * @dev: SPI slave device
134 * @max_hz: Maximum speed for this slave
135 * @bus: ID of the bus that the slave is attached to. For
136 * driver model this is the sequence number of the SPI
137 * bus (dev_seq(bus)) so does not need to be stored
138 * @cs: ID of the chip select connected to the slave.
139 * @mode: SPI mode to use for this slave (see SPI mode flags)
140 * @wordlen: Size of SPI word in number of bits
141 * @max_read_size: If non-zero, the maximum number of bytes which can
142 * be read at once.
143 * @max_write_size: If non-zero, the maximum number of bytes which can
144 * be written at once.
145 * @memory_map: Address of read-only SPI flash access.
146 * @flags: Indication of SPI flags.
147 */
148 struct spi_slave {
149 #if CONFIG_IS_ENABLED(DM_SPI)
150 struct udevice *dev; /* struct spi_slave is dev->parentdata */
151 uint max_hz;
152 #else
153 unsigned int bus;
154 unsigned int cs;
155 #endif
156 uint mode;
157 unsigned int wordlen;
158 unsigned int max_read_size;
159 unsigned int max_write_size;
160 void *memory_map;
161
162 u8 flags;
163 #define SPI_XFER_BEGIN BIT(0) /* Assert CS before transfer */
164 #define SPI_XFER_END BIT(1) /* Deassert CS after transfer */
165 #define SPI_XFER_ONCE (SPI_XFER_BEGIN | SPI_XFER_END)
166 #define SPI_XFER_U_PAGE BIT(4)
167 #define SPI_XFER_STACKED BIT(5)
168 #define SPI_XFER_LOWER BIT(6)
169
170 /*
171 * Flag indicating that the spi-controller has multi chip select
172 * capability and can assert/de-assert more than one chip select
173 * at once.
174 */
175 bool multi_cs_cap;
176 u32 bytemode;
177 };
178
179 /**
180 * spi_do_alloc_slave - Allocate a new SPI slave (internal)
181 *
182 * Allocate and zero all fields in the spi slave, and set the bus/chip
183 * select. Use the helper macro spi_alloc_slave() to call this.
184 *
185 * @offset: Offset of struct spi_slave within slave structure.
186 * @size: Size of slave structure.
187 * @bus: Bus ID of the slave chip.
188 * @cs: Chip select ID of the slave chip on the specified bus.
189 */
190 void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
191 unsigned int cs);
192
193 /**
194 * spi_alloc_slave - Allocate a new SPI slave
195 *
196 * Allocate and zero all fields in the spi slave, and set the bus/chip
197 * select.
198 *
199 * @_struct: Name of structure to allocate (e.g. struct tegra_spi).
200 * This structure must contain a member 'struct spi_slave *slave'.
201 * @bus: Bus ID of the slave chip.
202 * @cs: Chip select ID of the slave chip on the specified bus.
203 */
204 #define spi_alloc_slave(_struct, bus, cs) \
205 spi_do_alloc_slave(offsetof(_struct, slave), \
206 sizeof(_struct), bus, cs)
207
208 /**
209 * spi_alloc_slave_base - Allocate a new SPI slave with no private data
210 *
211 * Allocate and zero all fields in the spi slave, and set the bus/chip
212 * select.
213 *
214 * @bus: Bus ID of the slave chip.
215 * @cs: Chip select ID of the slave chip on the specified bus.
216 */
217 #define spi_alloc_slave_base(bus, cs) \
218 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
219
220 /**
221 * Set up communications parameters for a SPI slave.
222 *
223 * This must be called once for each slave. Note that this function
224 * usually doesn't touch any actual hardware, it only initializes the
225 * contents of spi_slave so that the hardware can be easily
226 * initialized later.
227 *
228 * @bus: Bus ID of the slave chip.
229 * @cs: Chip select ID of the slave chip on the specified bus.
230 * @max_hz: Maximum SCK rate in Hz.
231 * @mode: Clock polarity, clock phase and other parameters.
232 *
233 * Returns: A spi_slave reference that can be used in subsequent SPI
234 * calls, or NULL if one or more of the parameters are not supported.
235 */
236 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
237 unsigned int max_hz, unsigned int mode);
238
239 /**
240 * Free any memory associated with a SPI slave.
241 *
242 * @slave: The SPI slave
243 */
244 void spi_free_slave(struct spi_slave *slave);
245
246 /**
247 * Claim the bus and prepare it for communication with a given slave.
248 *
249 * This must be called before doing any transfers with a SPI slave. It
250 * will enable and initialize any SPI hardware as necessary, and make
251 * sure that the SCK line is in the correct idle state. It is not
252 * allowed to claim the same bus for several slaves without releasing
253 * the bus in between.
254 *
255 * @slave: The SPI slave
256 *
257 * Returns: 0 if the bus was claimed successfully, or a negative value
258 * if it wasn't.
259 */
260 int spi_claim_bus(struct spi_slave *slave);
261
262 /**
263 * Release the SPI bus
264 *
265 * This must be called once for every call to spi_claim_bus() after
266 * all transfers have finished. It may disable any SPI hardware as
267 * appropriate.
268 *
269 * @slave: The SPI slave
270 */
271 void spi_release_bus(struct spi_slave *slave);
272
273 /**
274 * Set the word length for SPI transactions
275 *
276 * Set the word length (number of bits per word) for SPI transactions.
277 *
278 * @slave: The SPI slave
279 * @wordlen: The number of bits in a word
280 *
281 * Returns: 0 on success, -1 on failure.
282 */
283 int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen);
284
285 /**
286 * SPI transfer (optional if mem_ops is used)
287 *
288 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
289 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
290 *
291 * The source of the outgoing bits is the "dout" parameter and the
292 * destination of the input bits is the "din" parameter. Note that "dout"
293 * and "din" can point to the same memory location, in which case the
294 * input data overwrites the output data (since both are buffered by
295 * temporary variables, this is OK).
296 *
297 * spi_xfer() interface:
298 * @slave: The SPI slave which will be sending/receiving the data.
299 * @bitlen: How many bits to write and read.
300 * @dout: Pointer to a string of bits to send out. The bits are
301 * held in a byte array and are sent MSB first.
302 * @din: Pointer to a string of bits that will be filled in.
303 * @flags: A bitwise combination of SPI_XFER_* flags.
304 *
305 * Returns: 0 on success, not 0 on failure
306 */
307 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
308 void *din, unsigned long flags);
309
310 /**
311 * spi_write_then_read - SPI synchronous write followed by read
312 *
313 * This performs a half duplex transaction in which the first transaction
314 * is to send the opcode and if the length of buf is non-zero then it start
315 * the second transaction as tx or rx based on the need from respective slave.
316 *
317 * @slave: The SPI slave device with which opcode/data will be exchanged
318 * @opcode: opcode used for specific transfer
319 * @n_opcode: size of opcode, in bytes
320 * @txbuf: buffer into which data to be written
321 * @rxbuf: buffer into which data will be read
322 * @n_buf: size of buf (whether it's [tx|rx]buf), in bytes
323 *
324 * Returns: 0 on success, not 0 on failure
325 */
326 int spi_write_then_read(struct spi_slave *slave, const u8 *opcode,
327 size_t n_opcode, const u8 *txbuf, u8 *rxbuf,
328 size_t n_buf);
329
330 /* Copy memory mapped data */
331 void spi_flash_copy_mmap(void *data, void *offset, size_t len);
332
333 /**
334 * Determine if a SPI chipselect is valid.
335 * This function is provided by the board if the low-level SPI driver
336 * needs it to determine if a given chipselect is actually valid.
337 *
338 * Returns: 1 if bus:cs identifies a valid chip on this board, 0
339 * otherwise.
340 */
341 int spi_cs_is_valid(unsigned int bus, unsigned int cs);
342
343 /*
344 * These names are used in several drivers and these declarations will be
345 * removed soon as part of the SPI DM migration. Drop them if driver model is
346 * enabled for SPI.
347 */
348 #if !CONFIG_IS_ENABLED(DM_SPI)
349 /**
350 * Activate a SPI chipselect.
351 * This function is provided by the board code when using a driver
352 * that can't control its chipselects automatically (e.g.
353 * common/soft_spi.c). When called, it should activate the chip select
354 * to the device identified by "slave".
355 */
356 void spi_cs_activate(struct spi_slave *slave);
357
358 /**
359 * Deactivate a SPI chipselect.
360 * This function is provided by the board code when using a driver
361 * that can't control its chipselects automatically (e.g.
362 * common/soft_spi.c). When called, it should deactivate the chip
363 * select to the device identified by "slave".
364 */
365 void spi_cs_deactivate(struct spi_slave *slave);
366 #endif
367
368 /**
369 * Set transfer speed.
370 * This sets a new speed to be applied for next spi_xfer().
371 * @slave: The SPI slave
372 * @hz: The transfer speed
373 *
374 * Returns: 0 on success, or a negative value on error.
375 */
376 int spi_set_speed(struct spi_slave *slave, uint hz);
377
378 /**
379 * Write 8 bits, then read 8 bits.
380 * @slave: The SPI slave we're communicating with
381 * @byte: Byte to be written
382 *
383 * Returns: The value that was read, or a negative value on error.
384 *
385 * TODO: This function probably shouldn't be inlined.
386 */
spi_w8r8(struct spi_slave * slave,unsigned char byte)387 static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
388 {
389 unsigned char dout[2];
390 unsigned char din[2];
391 int ret;
392
393 dout[0] = byte;
394 dout[1] = 0;
395
396 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
397 return ret < 0 ? ret : din[1];
398 }
399
400 /**
401 * struct spi_cs_info - Information about a bus chip select
402 *
403 * @dev: Connected device, or NULL if none
404 */
405 struct spi_cs_info {
406 struct udevice *dev;
407 };
408
409 /**
410 * struct struct dm_spi_ops - Driver model SPI operations
411 *
412 * The uclass interface is implemented by all SPI devices which use
413 * driver model.
414 */
415 struct dm_spi_ops {
416 /**
417 * Claim the bus and prepare it for communication.
418 *
419 * The device provided is the slave device. It's parent controller
420 * will be used to provide the communication.
421 *
422 * This must be called before doing any transfers with a SPI slave. It
423 * will enable and initialize any SPI hardware as necessary, and make
424 * sure that the SCK line is in the correct idle state. It is not
425 * allowed to claim the same bus for several slaves without releasing
426 * the bus in between.
427 *
428 * @dev: The SPI slave
429 *
430 * Returns: 0 if the bus was claimed successfully, or a negative value
431 * if it wasn't.
432 */
433 int (*claim_bus)(struct udevice *dev);
434
435 /**
436 * Release the SPI bus
437 *
438 * This must be called once for every call to spi_claim_bus() after
439 * all transfers have finished. It may disable any SPI hardware as
440 * appropriate.
441 *
442 * @dev: The SPI slave
443 */
444 int (*release_bus)(struct udevice *dev);
445
446 /**
447 * Set the word length for SPI transactions
448 *
449 * Set the word length (number of bits per word) for SPI transactions.
450 *
451 * @bus: The SPI slave
452 * @wordlen: The number of bits in a word
453 *
454 * Returns: 0 on success, -ve on failure.
455 */
456 int (*set_wordlen)(struct udevice *dev, unsigned int wordlen);
457
458 /**
459 * SPI transfer
460 *
461 * This writes "bitlen" bits out the SPI MOSI port and simultaneously
462 * clocks "bitlen" bits in the SPI MISO port. That's just the way SPI
463 * works.
464 *
465 * The source of the outgoing bits is the "dout" parameter and the
466 * destination of the input bits is the "din" parameter. Note that
467 * "dout" and "din" can point to the same memory location, in which
468 * case the input data overwrites the output data (since both are
469 * buffered by temporary variables, this is OK).
470 *
471 * spi_xfer() interface:
472 * @dev: The slave device to communicate with
473 * @bitlen: How many bits to write and read.
474 * @dout: Pointer to a string of bits to send out. The bits are
475 * held in a byte array and are sent MSB first.
476 * @din: Pointer to a string of bits that will be filled in.
477 * @flags: A bitwise combination of SPI_XFER_* flags.
478 *
479 * Returns: 0 on success, not -1 on failure
480 */
481 int (*xfer)(struct udevice *dev, unsigned int bitlen, const void *dout,
482 void *din, unsigned long flags);
483
484 /**
485 * Optimized handlers for SPI memory-like operations.
486 *
487 * Optimized/dedicated operations for interactions with SPI memory. This
488 * field is optional and should only be implemented if the controller
489 * has native support for memory like operations.
490 */
491 const struct spi_controller_mem_ops *mem_ops;
492
493 /**
494 * Set transfer speed.
495 * This sets a new speed to be applied for next spi_xfer().
496 * @bus: The SPI bus
497 * @hz: The transfer speed
498 * @return 0 if OK, -ve on error
499 */
500 int (*set_speed)(struct udevice *bus, uint hz);
501
502 /**
503 * Set the SPI mode/flags
504 *
505 * It is unclear if we want to set speed and mode together instead
506 * of separately.
507 *
508 * @bus: The SPI bus
509 * @mode: Requested SPI mode (SPI_... flags)
510 * @return 0 if OK, -ve on error
511 */
512 int (*set_mode)(struct udevice *bus, uint mode);
513
514 /**
515 * Get information on a chip select
516 *
517 * This is only called when the SPI uclass does not know about a
518 * chip select, i.e. it has no attached device. It gives the driver
519 * a chance to allow activity on that chip select even so.
520 *
521 * @bus: The SPI bus
522 * @cs: The chip select (0..n-1)
523 * @info: Returns information about the chip select, if valid.
524 * On entry info->dev is NULL
525 * @return 0 if OK (and @info is set up), -EINVAL if the chip select
526 * is invalid, other -ve value on error
527 */
528 int (*cs_info)(struct udevice *bus, uint cs, struct spi_cs_info *info);
529
530 /**
531 * get_mmap() - Get memory-mapped SPI
532 *
533 * @dev: The SPI flash slave device
534 * @map_basep: Returns base memory address for mapped SPI
535 * @map_sizep: Returns size of mapped SPI
536 * @offsetp: Returns start offset of SPI flash where the map works
537 * correctly (offsets before this are not visible)
538 * @return 0 if OK, -EFAULT if memory mapping is not available
539 */
540 int (*get_mmap)(struct udevice *dev, ulong *map_basep,
541 uint *map_sizep, uint *offsetp);
542
543 /**
544 * setup_for_spinand() - Setup the SPI for attached SPI NAND
545 *
546 * @dev: The SPI flash slave device
547 * @spinand_info: The SPI NAND info to configure for
548 * @return 0 if OK, -ve value on error
549 */
550 int (*setup_for_spinand)(struct spi_slave *slave,
551 const struct spinand_info *spinand_info);
552 };
553
554 struct dm_spi_emul_ops {
555 /**
556 * SPI transfer
557 *
558 * This writes "bitlen" bits out the SPI MOSI port and simultaneously
559 * clocks "bitlen" bits in the SPI MISO port. That's just the way SPI
560 * works. Here the device is a slave.
561 *
562 * The source of the outgoing bits is the "dout" parameter and the
563 * destination of the input bits is the "din" parameter. Note that
564 * "dout" and "din" can point to the same memory location, in which
565 * case the input data overwrites the output data (since both are
566 * buffered by temporary variables, this is OK).
567 *
568 * spi_xfer() interface:
569 * @slave: The SPI slave which will be sending/receiving the data.
570 * @bitlen: How many bits to write and read.
571 * @dout: Pointer to a string of bits sent to the device. The
572 * bits are held in a byte array and are sent MSB first.
573 * @din: Pointer to a string of bits that will be sent back to
574 * the master.
575 * @flags: A bitwise combination of SPI_XFER_* flags.
576 *
577 * Returns: 0 on success, not -1 on failure
578 */
579 int (*xfer)(struct udevice *slave, unsigned int bitlen,
580 const void *dout, void *din, unsigned long flags);
581 };
582
583 /**
584 * spi_find_bus_and_cs() - Find bus and slave devices by number
585 *
586 * Given a bus number and chip select, this finds the corresponding bus
587 * device and slave device. Neither device is activated by this function,
588 * although they may have been activated previously.
589 *
590 * @busnum: SPI bus number
591 * @cs: Chip select to look for
592 * @busp: Returns bus device
593 * @devp: Return slave device
594 * Return: 0 if found, -ENODEV on error
595 */
596 int spi_find_bus_and_cs(int busnum, int cs, struct udevice **busp,
597 struct udevice **devp);
598
599 /**
600 * spi_get_bus_and_cs() - Find and activate bus and slave devices by number
601 *
602 * Given a bus number and chip select, this finds the corresponding bus
603 * device and slave device.
604 *
605 * @busnum: SPI bus number
606 * @cs: Chip select to look for
607 * @busp: Returns bus device
608 * @devp: Return slave device
609 * @return 0 if found, -ve on error
610 */
611 int spi_get_bus_and_cs(int busnum, int cs,
612 struct udevice **busp, struct spi_slave **devp);
613
614 /**
615 * _spi_get_bus_and_cs() - Find and activate bus and slave devices by number
616 * As spi_flash_probe(), This is an old-style function. We should remove
617 * it when all SPI flash drivers use dm
618 *
619 * Given a bus number and chip select, this finds the corresponding bus
620 * device and slave device.
621 *
622 * If no such slave exists, and drv_name is not NULL, then a new slave device
623 * is automatically bound on this chip select with requested speed and mode.
624 *
625 * Ths new slave device is probed ready for use with the speed and mode
626 * from plat when available or the requested values.
627 *
628 * @busnum: SPI bus number
629 * @cs: Chip select to look for
630 * @speed: SPI speed to use for this slave when not available in plat
631 * @mode: SPI mode to use for this slave when not available in plat
632 * @drv_name: Name of driver to attach to this chip select
633 * @dev_name: Name of the new device thus created
634 * @busp: Returns bus device
635 * @devp: Return slave device
636 * Return: 0 if found, -ve on error
637 */
638 int _spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
639 const char *drv_name, const char *dev_name,
640 struct udevice **busp, struct spi_slave **devp);
641
642 /**
643 * spi_chip_select() - Get the chip select for a slave
644 *
645 * Return: the chip select this slave is attached to
646 */
647 int spi_chip_select(struct udevice *slave);
648
649 /**
650 * spi_find_chip_select() - Find the slave attached to chip select
651 *
652 * @bus: SPI bus to search
653 * @cs: Chip select to look for
654 * @devp: Returns the slave device if found
655 * Return: 0 if found, -EINVAL if cs is invalid, -ENODEV if no device attached,
656 * other -ve value on error
657 */
658 int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp);
659
660 /**
661 * spi_slave_of_to_plat() - decode standard SPI platform data
662 *
663 * This decodes the speed and mode for a slave from a device tree node
664 *
665 * @blob: Device tree blob
666 * @node: Node offset to read from
667 * @plat: Place to put the decoded information
668 */
669 int spi_slave_of_to_plat(struct udevice *dev, struct dm_spi_slave_plat *plat);
670
671 /**
672 * spi_cs_info() - Check information on a chip select
673 *
674 * This checks a particular chip select on a bus to see if it has a device
675 * attached, or is even valid.
676 *
677 * @bus: The SPI bus
678 * @cs: The chip select (0..n-1)
679 * @info: Returns information about the chip select, if valid
680 * Return: 0 if OK (and @info is set up), -ENODEV if the chip select
681 * is invalid, other -ve value on error
682 */
683 int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info);
684
685 struct sandbox_state;
686
687 /**
688 * sandbox_spi_get_emul() - get an emulator for a SPI slave
689 *
690 * This provides a way to attach an emulated SPI device to a particular SPI
691 * slave, so that xfer() operations on the slave will be handled by the
692 * emulator. If a emulator already exists on that chip select it is returned.
693 * Otherwise one is created.
694 *
695 * @state: Sandbox state
696 * @bus: SPI bus requesting the emulator
697 * @slave: SPI slave device requesting the emulator
698 * @emuip: Returns pointer to emulator
699 * Return: 0 if OK, -ve on error
700 */
701 int sandbox_spi_get_emul(struct sandbox_state *state,
702 struct udevice *bus, struct udevice *slave,
703 struct udevice **emulp);
704
705 /**
706 * Claim the bus and prepare it for communication with a given slave.
707 *
708 * This must be called before doing any transfers with a SPI slave. It
709 * will enable and initialize any SPI hardware as necessary, and make
710 * sure that the SCK line is in the correct idle state. It is not
711 * allowed to claim the same bus for several slaves without releasing
712 * the bus in between.
713 *
714 * @dev: The SPI slave device
715 *
716 * Returns: 0 if the bus was claimed successfully, or a negative value
717 * if it wasn't.
718 */
719 int dm_spi_claim_bus(struct udevice *dev);
720
721 /**
722 * Release the SPI bus
723 *
724 * This must be called once for every call to dm_spi_claim_bus() after
725 * all transfers have finished. It may disable any SPI hardware as
726 * appropriate.
727 *
728 * @slave: The SPI slave device
729 */
730 void dm_spi_release_bus(struct udevice *dev);
731
732 /**
733 * SPI transfer
734 *
735 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
736 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
737 *
738 * The source of the outgoing bits is the "dout" parameter and the
739 * destination of the input bits is the "din" parameter. Note that "dout"
740 * and "din" can point to the same memory location, in which case the
741 * input data overwrites the output data (since both are buffered by
742 * temporary variables, this is OK).
743 *
744 * dm_spi_xfer() interface:
745 * @dev: The SPI slave device which will be sending/receiving the data.
746 * @bitlen: How many bits to write and read.
747 * @dout: Pointer to a string of bits to send out. The bits are
748 * held in a byte array and are sent MSB first.
749 * @din: Pointer to a string of bits that will be filled in.
750 * @flags: A bitwise combination of SPI_XFER_* flags.
751 *
752 * Returns: 0 on success, not 0 on failure
753 */
754 int dm_spi_xfer(struct udevice *dev, unsigned int bitlen,
755 const void *dout, void *din, unsigned long flags);
756
757 /**
758 * spi_get_mmap() - Get memory-mapped SPI
759 *
760 * @dev: SPI slave device to check
761 * @map_basep: Returns base memory address for mapped SPI
762 * @map_sizep: Returns size of mapped SPI
763 * @offsetp: Returns start offset of SPI flash where the map works
764 * correctly (offsets before this are not visible)
765 * Return: 0 if OK, -ENOSYS if no operation, -EFAULT if memory mapping is not
766 * available
767 */
768 int dm_spi_get_mmap(struct udevice *dev, ulong *map_basep, uint *map_sizep,
769 uint *offsetp);
770
771 /* Access the operations for a SPI device */
772 #define spi_get_ops(dev) ((struct dm_spi_ops *)(dev)->driver->ops)
773 #define spi_emul_get_ops(dev) ((struct dm_spi_emul_ops *)(dev)->driver->ops)
774
775 int spi_get_env_dev(void);
776
777 #endif /* _SPI_H_ */
778