spi.h 21 KB

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  1. /*
  2. * Common SPI Interface: Controller-specific definitions
  3. *
  4. * (C) Copyright 2001
  5. * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
  6. *
  7. * SPDX-License-Identifier: GPL-2.0+
  8. */
  9. #ifndef _SPI_H_
  10. #define _SPI_H_
  11. /* SPI mode flags */
  12. #define SPI_CPHA BIT(0) /* clock phase */
  13. #define SPI_CPOL BIT(1) /* clock polarity */
  14. #define SPI_MODE_0 (0|0) /* (original MicroWire) */
  15. #define SPI_MODE_1 (0|SPI_CPHA)
  16. #define SPI_MODE_2 (SPI_CPOL|0)
  17. #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
  18. #define SPI_CS_HIGH BIT(2) /* CS active high */
  19. #define SPI_LSB_FIRST BIT(3) /* per-word bits-on-wire */
  20. #define SPI_3WIRE BIT(4) /* SI/SO signals shared */
  21. #define SPI_LOOP BIT(5) /* loopback mode */
  22. #define SPI_SLAVE BIT(6) /* slave mode */
  23. #define SPI_PREAMBLE BIT(7) /* Skip preamble bytes */
  24. #define SPI_TX_BYTE BIT(8) /* transmit with 1 wire byte */
  25. #define SPI_TX_DUAL BIT(9) /* transmit with 2 wires */
  26. #define SPI_TX_QUAD BIT(10) /* transmit with 4 wires */
  27. #define SPI_RX_SLOW BIT(11) /* receive with 1 wire slow */
  28. #define SPI_RX_DUAL BIT(12) /* receive with 2 wires */
  29. #define SPI_RX_QUAD BIT(13) /* receive with 4 wires */
  30. /* Header byte that marks the start of the message */
  31. #define SPI_PREAMBLE_END_BYTE 0xec
  32. #define SPI_DEFAULT_WORDLEN 8
  33. #ifdef CONFIG_DM_SPI
  34. /* TODO(sjg@chromium.org): Remove this and use max_hz from struct spi_slave */
  35. struct dm_spi_bus {
  36. uint max_hz;
  37. };
  38. /**
  39. * struct dm_spi_platdata - platform data for all SPI slaves
  40. *
  41. * This describes a SPI slave, a child device of the SPI bus. To obtain this
  42. * struct from a spi_slave, use dev_get_parent_platdata(dev) or
  43. * dev_get_parent_platdata(slave->dev).
  44. *
  45. * This data is immuatable. Each time the device is probed, @max_hz and @mode
  46. * will be copied to struct spi_slave.
  47. *
  48. * @cs: Chip select number (0..n-1)
  49. * @max_hz: Maximum bus speed that this slave can tolerate
  50. * @mode: SPI mode to use for this device (see SPI mode flags)
  51. */
  52. struct dm_spi_slave_platdata {
  53. unsigned int cs;
  54. uint max_hz;
  55. uint mode;
  56. };
  57. #endif /* CONFIG_DM_SPI */
  58. /**
  59. * struct spi_slave - Representation of a SPI slave
  60. *
  61. * For driver model this is the per-child data used by the SPI bus. It can
  62. * be accessed using dev_get_parent_priv() on the slave device. The SPI uclass
  63. * sets uip per_child_auto_alloc_size to sizeof(struct spi_slave), and the
  64. * driver should not override it. Two platform data fields (max_hz and mode)
  65. * are copied into this structure to provide an initial value. This allows
  66. * them to be changed, since we should never change platform data in drivers.
  67. *
  68. * If not using driver model, drivers are expected to extend this with
  69. * controller-specific data.
  70. *
  71. * @dev: SPI slave device
  72. * @max_hz: Maximum speed for this slave
  73. * @speed: Current bus speed. This is 0 until the bus is first
  74. * claimed.
  75. * @bus: ID of the bus that the slave is attached to. For
  76. * driver model this is the sequence number of the SPI
  77. * bus (bus->seq) so does not need to be stored
  78. * @cs: ID of the chip select connected to the slave.
  79. * @mode: SPI mode to use for this slave (see SPI mode flags)
  80. * @wordlen: Size of SPI word in number of bits
  81. * @max_write_size: If non-zero, the maximum number of bytes which can
  82. * be written at once, excluding command bytes.
  83. * @memory_map: Address of read-only SPI flash access.
  84. * @flags: Indication of SPI flags.
  85. */
  86. struct spi_slave {
  87. #ifdef CONFIG_DM_SPI
  88. struct udevice *dev; /* struct spi_slave is dev->parentdata */
  89. uint max_hz;
  90. uint speed;
  91. #else
  92. unsigned int bus;
  93. unsigned int cs;
  94. #endif
  95. uint mode;
  96. unsigned int wordlen;
  97. unsigned int max_write_size;
  98. void *memory_map;
  99. u8 option;
  100. u8 flags;
  101. #define SPI_XFER_BEGIN BIT(0) /* Assert CS before transfer */
  102. #define SPI_XFER_END BIT(1) /* Deassert CS after transfer */
  103. #define SPI_XFER_ONCE (SPI_XFER_BEGIN | SPI_XFER_END)
  104. #define SPI_XFER_MMAP BIT(2) /* Memory Mapped start */
  105. #define SPI_XFER_MMAP_END BIT(3) /* Memory Mapped End */
  106. };
  107. /**
  108. * Initialization, must be called once on start up.
  109. *
  110. * TODO: I don't think we really need this.
  111. */
  112. void spi_init(void);
  113. /**
  114. * spi_do_alloc_slave - Allocate a new SPI slave (internal)
  115. *
  116. * Allocate and zero all fields in the spi slave, and set the bus/chip
  117. * select. Use the helper macro spi_alloc_slave() to call this.
  118. *
  119. * @offset: Offset of struct spi_slave within slave structure.
  120. * @size: Size of slave structure.
  121. * @bus: Bus ID of the slave chip.
  122. * @cs: Chip select ID of the slave chip on the specified bus.
  123. */
  124. void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
  125. unsigned int cs);
  126. /**
  127. * spi_alloc_slave - Allocate a new SPI slave
  128. *
  129. * Allocate and zero all fields in the spi slave, and set the bus/chip
  130. * select.
  131. *
  132. * @_struct: Name of structure to allocate (e.g. struct tegra_spi).
  133. * This structure must contain a member 'struct spi_slave *slave'.
  134. * @bus: Bus ID of the slave chip.
  135. * @cs: Chip select ID of the slave chip on the specified bus.
  136. */
  137. #define spi_alloc_slave(_struct, bus, cs) \
  138. spi_do_alloc_slave(offsetof(_struct, slave), \
  139. sizeof(_struct), bus, cs)
  140. /**
  141. * spi_alloc_slave_base - Allocate a new SPI slave with no private data
  142. *
  143. * Allocate and zero all fields in the spi slave, and set the bus/chip
  144. * select.
  145. *
  146. * @bus: Bus ID of the slave chip.
  147. * @cs: Chip select ID of the slave chip on the specified bus.
  148. */
  149. #define spi_alloc_slave_base(bus, cs) \
  150. spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
  151. /**
  152. * Set up communications parameters for a SPI slave.
  153. *
  154. * This must be called once for each slave. Note that this function
  155. * usually doesn't touch any actual hardware, it only initializes the
  156. * contents of spi_slave so that the hardware can be easily
  157. * initialized later.
  158. *
  159. * @bus: Bus ID of the slave chip.
  160. * @cs: Chip select ID of the slave chip on the specified bus.
  161. * @max_hz: Maximum SCK rate in Hz.
  162. * @mode: Clock polarity, clock phase and other parameters.
  163. *
  164. * Returns: A spi_slave reference that can be used in subsequent SPI
  165. * calls, or NULL if one or more of the parameters are not supported.
  166. */
  167. struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  168. unsigned int max_hz, unsigned int mode);
  169. /**
  170. * Free any memory associated with a SPI slave.
  171. *
  172. * @slave: The SPI slave
  173. */
  174. void spi_free_slave(struct spi_slave *slave);
  175. /**
  176. * Claim the bus and prepare it for communication with a given slave.
  177. *
  178. * This must be called before doing any transfers with a SPI slave. It
  179. * will enable and initialize any SPI hardware as necessary, and make
  180. * sure that the SCK line is in the correct idle state. It is not
  181. * allowed to claim the same bus for several slaves without releasing
  182. * the bus in between.
  183. *
  184. * @slave: The SPI slave
  185. *
  186. * Returns: 0 if the bus was claimed successfully, or a negative value
  187. * if it wasn't.
  188. */
  189. int spi_claim_bus(struct spi_slave *slave);
  190. /**
  191. * Release the SPI bus
  192. *
  193. * This must be called once for every call to spi_claim_bus() after
  194. * all transfers have finished. It may disable any SPI hardware as
  195. * appropriate.
  196. *
  197. * @slave: The SPI slave
  198. */
  199. void spi_release_bus(struct spi_slave *slave);
  200. /**
  201. * Set the word length for SPI transactions
  202. *
  203. * Set the word length (number of bits per word) for SPI transactions.
  204. *
  205. * @slave: The SPI slave
  206. * @wordlen: The number of bits in a word
  207. *
  208. * Returns: 0 on success, -1 on failure.
  209. */
  210. int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen);
  211. /**
  212. * SPI transfer
  213. *
  214. * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
  215. * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
  216. *
  217. * The source of the outgoing bits is the "dout" parameter and the
  218. * destination of the input bits is the "din" parameter. Note that "dout"
  219. * and "din" can point to the same memory location, in which case the
  220. * input data overwrites the output data (since both are buffered by
  221. * temporary variables, this is OK).
  222. *
  223. * spi_xfer() interface:
  224. * @slave: The SPI slave which will be sending/receiving the data.
  225. * @bitlen: How many bits to write and read.
  226. * @dout: Pointer to a string of bits to send out. The bits are
  227. * held in a byte array and are sent MSB first.
  228. * @din: Pointer to a string of bits that will be filled in.
  229. * @flags: A bitwise combination of SPI_XFER_* flags.
  230. *
  231. * Returns: 0 on success, not 0 on failure
  232. */
  233. int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
  234. void *din, unsigned long flags);
  235. /* Copy memory mapped data */
  236. void spi_flash_copy_mmap(void *data, void *offset, size_t len);
  237. /**
  238. * Determine if a SPI chipselect is valid.
  239. * This function is provided by the board if the low-level SPI driver
  240. * needs it to determine if a given chipselect is actually valid.
  241. *
  242. * Returns: 1 if bus:cs identifies a valid chip on this board, 0
  243. * otherwise.
  244. */
  245. int spi_cs_is_valid(unsigned int bus, unsigned int cs);
  246. #ifndef CONFIG_DM_SPI
  247. /**
  248. * Activate a SPI chipselect.
  249. * This function is provided by the board code when using a driver
  250. * that can't control its chipselects automatically (e.g.
  251. * common/soft_spi.c). When called, it should activate the chip select
  252. * to the device identified by "slave".
  253. */
  254. void spi_cs_activate(struct spi_slave *slave);
  255. /**
  256. * Deactivate a SPI chipselect.
  257. * This function is provided by the board code when using a driver
  258. * that can't control its chipselects automatically (e.g.
  259. * common/soft_spi.c). When called, it should deactivate the chip
  260. * select to the device identified by "slave".
  261. */
  262. void spi_cs_deactivate(struct spi_slave *slave);
  263. /**
  264. * Set transfer speed.
  265. * This sets a new speed to be applied for next spi_xfer().
  266. * @slave: The SPI slave
  267. * @hz: The transfer speed
  268. */
  269. void spi_set_speed(struct spi_slave *slave, uint hz);
  270. #endif
  271. /**
  272. * Write 8 bits, then read 8 bits.
  273. * @slave: The SPI slave we're communicating with
  274. * @byte: Byte to be written
  275. *
  276. * Returns: The value that was read, or a negative value on error.
  277. *
  278. * TODO: This function probably shouldn't be inlined.
  279. */
  280. static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
  281. {
  282. unsigned char dout[2];
  283. unsigned char din[2];
  284. int ret;
  285. dout[0] = byte;
  286. dout[1] = 0;
  287. ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
  288. return ret < 0 ? ret : din[1];
  289. }
  290. /**
  291. * Set up a SPI slave for a particular device tree node
  292. *
  293. * This calls spi_setup_slave() with the correct bus number. Call
  294. * spi_free_slave() to free it later.
  295. *
  296. * @param blob: Device tree blob
  297. * @param slave_node: Slave node to use
  298. * @param spi_node: SPI peripheral node to use
  299. * @return pointer to new spi_slave structure
  300. */
  301. struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node,
  302. int spi_node);
  303. /**
  304. * spi_base_setup_slave_fdt() - helper function to set up a SPI slace
  305. *
  306. * This decodes SPI properties from the slave node to determine the
  307. * chip select and SPI parameters.
  308. *
  309. * @blob: Device tree blob
  310. * @busnum: Bus number to use
  311. * @node: Device tree node for the SPI bus
  312. */
  313. struct spi_slave *spi_base_setup_slave_fdt(const void *blob, int busnum,
  314. int node);
  315. #ifdef CONFIG_DM_SPI
  316. /**
  317. * struct spi_cs_info - Information about a bus chip select
  318. *
  319. * @dev: Connected device, or NULL if none
  320. */
  321. struct spi_cs_info {
  322. struct udevice *dev;
  323. };
  324. /**
  325. * struct struct dm_spi_ops - Driver model SPI operations
  326. *
  327. * The uclass interface is implemented by all SPI devices which use
  328. * driver model.
  329. */
  330. struct dm_spi_ops {
  331. /**
  332. * Claim the bus and prepare it for communication.
  333. *
  334. * The device provided is the slave device. It's parent controller
  335. * will be used to provide the communication.
  336. *
  337. * This must be called before doing any transfers with a SPI slave. It
  338. * will enable and initialize any SPI hardware as necessary, and make
  339. * sure that the SCK line is in the correct idle state. It is not
  340. * allowed to claim the same bus for several slaves without releasing
  341. * the bus in between.
  342. *
  343. * @dev: The SPI slave
  344. *
  345. * Returns: 0 if the bus was claimed successfully, or a negative value
  346. * if it wasn't.
  347. */
  348. int (*claim_bus)(struct udevice *dev);
  349. /**
  350. * Release the SPI bus
  351. *
  352. * This must be called once for every call to spi_claim_bus() after
  353. * all transfers have finished. It may disable any SPI hardware as
  354. * appropriate.
  355. *
  356. * @dev: The SPI slave
  357. */
  358. int (*release_bus)(struct udevice *dev);
  359. /**
  360. * Set the word length for SPI transactions
  361. *
  362. * Set the word length (number of bits per word) for SPI transactions.
  363. *
  364. * @bus: The SPI slave
  365. * @wordlen: The number of bits in a word
  366. *
  367. * Returns: 0 on success, -ve on failure.
  368. */
  369. int (*set_wordlen)(struct udevice *dev, unsigned int wordlen);
  370. /**
  371. * SPI transfer
  372. *
  373. * This writes "bitlen" bits out the SPI MOSI port and simultaneously
  374. * clocks "bitlen" bits in the SPI MISO port. That's just the way SPI
  375. * works.
  376. *
  377. * The source of the outgoing bits is the "dout" parameter and the
  378. * destination of the input bits is the "din" parameter. Note that
  379. * "dout" and "din" can point to the same memory location, in which
  380. * case the input data overwrites the output data (since both are
  381. * buffered by temporary variables, this is OK).
  382. *
  383. * spi_xfer() interface:
  384. * @dev: The slave device to communicate with
  385. * @bitlen: How many bits to write and read.
  386. * @dout: Pointer to a string of bits to send out. The bits are
  387. * held in a byte array and are sent MSB first.
  388. * @din: Pointer to a string of bits that will be filled in.
  389. * @flags: A bitwise combination of SPI_XFER_* flags.
  390. *
  391. * Returns: 0 on success, not -1 on failure
  392. */
  393. int (*xfer)(struct udevice *dev, unsigned int bitlen, const void *dout,
  394. void *din, unsigned long flags);
  395. /**
  396. * Set transfer speed.
  397. * This sets a new speed to be applied for next spi_xfer().
  398. * @bus: The SPI bus
  399. * @hz: The transfer speed
  400. * @return 0 if OK, -ve on error
  401. */
  402. int (*set_speed)(struct udevice *bus, uint hz);
  403. /**
  404. * Set the SPI mode/flags
  405. *
  406. * It is unclear if we want to set speed and mode together instead
  407. * of separately.
  408. *
  409. * @bus: The SPI bus
  410. * @mode: Requested SPI mode (SPI_... flags)
  411. * @return 0 if OK, -ve on error
  412. */
  413. int (*set_mode)(struct udevice *bus, uint mode);
  414. /**
  415. * Get information on a chip select
  416. *
  417. * This is only called when the SPI uclass does not know about a
  418. * chip select, i.e. it has no attached device. It gives the driver
  419. * a chance to allow activity on that chip select even so.
  420. *
  421. * @bus: The SPI bus
  422. * @cs: The chip select (0..n-1)
  423. * @info: Returns information about the chip select, if valid.
  424. * On entry info->dev is NULL
  425. * @return 0 if OK (and @info is set up), -ENODEV if the chip select
  426. * is invalid, other -ve value on error
  427. */
  428. int (*cs_info)(struct udevice *bus, uint cs, struct spi_cs_info *info);
  429. };
  430. struct dm_spi_emul_ops {
  431. /**
  432. * SPI transfer
  433. *
  434. * This writes "bitlen" bits out the SPI MOSI port and simultaneously
  435. * clocks "bitlen" bits in the SPI MISO port. That's just the way SPI
  436. * works. Here the device is a slave.
  437. *
  438. * The source of the outgoing bits is the "dout" parameter and the
  439. * destination of the input bits is the "din" parameter. Note that
  440. * "dout" and "din" can point to the same memory location, in which
  441. * case the input data overwrites the output data (since both are
  442. * buffered by temporary variables, this is OK).
  443. *
  444. * spi_xfer() interface:
  445. * @slave: The SPI slave which will be sending/receiving the data.
  446. * @bitlen: How many bits to write and read.
  447. * @dout: Pointer to a string of bits sent to the device. The
  448. * bits are held in a byte array and are sent MSB first.
  449. * @din: Pointer to a string of bits that will be sent back to
  450. * the master.
  451. * @flags: A bitwise combination of SPI_XFER_* flags.
  452. *
  453. * Returns: 0 on success, not -1 on failure
  454. */
  455. int (*xfer)(struct udevice *slave, unsigned int bitlen,
  456. const void *dout, void *din, unsigned long flags);
  457. };
  458. /**
  459. * spi_find_bus_and_cs() - Find bus and slave devices by number
  460. *
  461. * Given a bus number and chip select, this finds the corresponding bus
  462. * device and slave device. Neither device is activated by this function,
  463. * although they may have been activated previously.
  464. *
  465. * @busnum: SPI bus number
  466. * @cs: Chip select to look for
  467. * @busp: Returns bus device
  468. * @devp: Return slave device
  469. * @return 0 if found, -ENODEV on error
  470. */
  471. int spi_find_bus_and_cs(int busnum, int cs, struct udevice **busp,
  472. struct udevice **devp);
  473. /**
  474. * spi_get_bus_and_cs() - Find and activate bus and slave devices by number
  475. *
  476. * Given a bus number and chip select, this finds the corresponding bus
  477. * device and slave device.
  478. *
  479. * If no such slave exists, and drv_name is not NULL, then a new slave device
  480. * is automatically bound on this chip select.
  481. *
  482. * Ths new slave device is probed ready for use with the given speed and mode.
  483. *
  484. * @busnum: SPI bus number
  485. * @cs: Chip select to look for
  486. * @speed: SPI speed to use for this slave
  487. * @mode: SPI mode to use for this slave
  488. * @drv_name: Name of driver to attach to this chip select
  489. * @dev_name: Name of the new device thus created
  490. * @busp: Returns bus device
  491. * @devp: Return slave device
  492. * @return 0 if found, -ve on error
  493. */
  494. int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
  495. const char *drv_name, const char *dev_name,
  496. struct udevice **busp, struct spi_slave **devp);
  497. /**
  498. * spi_chip_select() - Get the chip select for a slave
  499. *
  500. * @return the chip select this slave is attached to
  501. */
  502. int spi_chip_select(struct udevice *slave);
  503. /**
  504. * spi_find_chip_select() - Find the slave attached to chip select
  505. *
  506. * @bus: SPI bus to search
  507. * @cs: Chip select to look for
  508. * @devp: Returns the slave device if found
  509. * @return 0 if found, -ENODEV on error
  510. */
  511. int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp);
  512. /**
  513. * spi_slave_ofdata_to_platdata() - decode standard SPI platform data
  514. *
  515. * This decodes the speed and mode for a slave from a device tree node
  516. *
  517. * @blob: Device tree blob
  518. * @node: Node offset to read from
  519. * @plat: Place to put the decoded information
  520. */
  521. int spi_slave_ofdata_to_platdata(const void *blob, int node,
  522. struct dm_spi_slave_platdata *plat);
  523. /**
  524. * spi_cs_info() - Check information on a chip select
  525. *
  526. * This checks a particular chip select on a bus to see if it has a device
  527. * attached, or is even valid.
  528. *
  529. * @bus: The SPI bus
  530. * @cs: The chip select (0..n-1)
  531. * @info: Returns information about the chip select, if valid
  532. * @return 0 if OK (and @info is set up), -ENODEV if the chip select
  533. * is invalid, other -ve value on error
  534. */
  535. int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info);
  536. struct sandbox_state;
  537. /**
  538. * sandbox_spi_get_emul() - get an emulator for a SPI slave
  539. *
  540. * This provides a way to attach an emulated SPI device to a particular SPI
  541. * slave, so that xfer() operations on the slave will be handled by the
  542. * emulator. If a emulator already exists on that chip select it is returned.
  543. * Otherwise one is created.
  544. *
  545. * @state: Sandbox state
  546. * @bus: SPI bus requesting the emulator
  547. * @slave: SPI slave device requesting the emulator
  548. * @emuip: Returns pointer to emulator
  549. * @return 0 if OK, -ve on error
  550. */
  551. int sandbox_spi_get_emul(struct sandbox_state *state,
  552. struct udevice *bus, struct udevice *slave,
  553. struct udevice **emulp);
  554. /**
  555. * Claim the bus and prepare it for communication with a given slave.
  556. *
  557. * This must be called before doing any transfers with a SPI slave. It
  558. * will enable and initialize any SPI hardware as necessary, and make
  559. * sure that the SCK line is in the correct idle state. It is not
  560. * allowed to claim the same bus for several slaves without releasing
  561. * the bus in between.
  562. *
  563. * @dev: The SPI slave device
  564. *
  565. * Returns: 0 if the bus was claimed successfully, or a negative value
  566. * if it wasn't.
  567. */
  568. int dm_spi_claim_bus(struct udevice *dev);
  569. /**
  570. * Release the SPI bus
  571. *
  572. * This must be called once for every call to dm_spi_claim_bus() after
  573. * all transfers have finished. It may disable any SPI hardware as
  574. * appropriate.
  575. *
  576. * @slave: The SPI slave device
  577. */
  578. void dm_spi_release_bus(struct udevice *dev);
  579. /**
  580. * SPI transfer
  581. *
  582. * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
  583. * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
  584. *
  585. * The source of the outgoing bits is the "dout" parameter and the
  586. * destination of the input bits is the "din" parameter. Note that "dout"
  587. * and "din" can point to the same memory location, in which case the
  588. * input data overwrites the output data (since both are buffered by
  589. * temporary variables, this is OK).
  590. *
  591. * dm_spi_xfer() interface:
  592. * @dev: The SPI slave device which will be sending/receiving the data.
  593. * @bitlen: How many bits to write and read.
  594. * @dout: Pointer to a string of bits to send out. The bits are
  595. * held in a byte array and are sent MSB first.
  596. * @din: Pointer to a string of bits that will be filled in.
  597. * @flags: A bitwise combination of SPI_XFER_* flags.
  598. *
  599. * Returns: 0 on success, not 0 on failure
  600. */
  601. int dm_spi_xfer(struct udevice *dev, unsigned int bitlen,
  602. const void *dout, void *din, unsigned long flags);
  603. /* Access the operations for a SPI device */
  604. #define spi_get_ops(dev) ((struct dm_spi_ops *)(dev)->driver->ops)
  605. #define spi_emul_get_ops(dev) ((struct dm_spi_emul_ops *)(dev)->driver->ops)
  606. #endif /* CONFIG_DM_SPI */
  607. #endif /* _SPI_H_ */