1 /* SPDX-License-Identifier: GPL-2.0-or-later
25  * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
26  * and SPI infrastructure.
31  * struct spi_statistics - statistics for spi transfers
34  * @messages:      number of spi-messages handled
85 		spin_lock_irqsave(&(stats)->lock, flags);	\
86 		(stats)->field += count;			\
87 		spin_unlock_irqrestore(&(stats)->lock, flags);	\
94  * struct spi_delay - SPI delay information
110  * struct spi_device - Controller side proxy for an SPI slave device
112  * @controller: SPI controller used with the device.
118  * @mode: The spi mode defines how data is clocked out and in.
124  *	like eight or 12 bits are common.  In-memory wordsizes are
133  * @controller_data: Board-specific definitions for controller, such as
140  * @cs_gpio: LEGACY: gpio number of the chipselect line (optional, -ENOENT when
150  * A @spi_device is used to interchange data between an SPI slave
175 #define	SPI_LSB_FIRST	0x08			/* per-word bits-on-wire */
179 #define	SPI_READY	0x80			/* slave pulls low to pause */
195 	struct spi_delay	word_delay; /* inter-word delay */
203 	 *  - memory packing (12 bit samples into low bits, others zeroed)
204 	 *  - priority
205 	 *  - chipselect delays
206 	 *  - ...
216 static inline struct spi_device *spi_dev_get(struct spi_device *spi)  in spi_dev_get()  argument
218 	return (spi && get_device(&spi->dev)) ? spi : NULL;  in spi_dev_get()
221 static inline void spi_dev_put(struct spi_device *spi)  in spi_dev_put()  argument
223 	if (spi)  in spi_dev_put()
224 		put_device(&spi->dev);  in spi_dev_put()
228 static inline void *spi_get_ctldata(struct spi_device *spi)  in spi_get_ctldata()  argument
230 	return spi->controller_state;  in spi_get_ctldata()
233 static inline void spi_set_ctldata(struct spi_device *spi, void *state)  in spi_set_ctldata()  argument
235 	spi->controller_state = state;  in spi_set_ctldata()
240 static inline void spi_set_drvdata(struct spi_device *spi, void *data)  in spi_set_drvdata()  argument
242 	dev_set_drvdata(&spi->dev, data);  in spi_set_drvdata()
245 static inline void *spi_get_drvdata(struct spi_device *spi)  in spi_get_drvdata()  argument
247 	return dev_get_drvdata(&spi->dev);  in spi_get_drvdata()
254  * struct spi_driver - Host side "protocol" driver
255  * @id_table: List of SPI devices supported by this driver
256  * @probe: Binds this driver to the spi device.  Drivers can verify
260  * @remove: Unbinds this driver from the spi device
263  * @driver: SPI device drivers should initialize the name and owner
266  * This represents the kind of device driver that uses SPI messages to
267  * interact with the hardware at the other end of a SPI link.  It's called
269  * directly to SPI hardware (which is what the underlying SPI controller
280 	int			(*probe)(struct spi_device *spi);
281 	int			(*remove)(struct spi_device *spi);
282 	void			(*shutdown)(struct spi_device *spi);
294  * spi_unregister_driver - reverse effect of spi_register_driver
301 		driver_unregister(&sdrv->driver);  in spi_unregister_driver()
309  * module_spi_driver() - Helper macro for registering a SPI driver
312  * Helper macro for SPI drivers which do not do anything special in module
321  * struct spi_controller - interface to SPI master or slave controller
324  * @bus_num: board-specific (and often SOC-specific) identifier for a
325  *	given SPI controller.
327  *	SPI slaves, and are numbered from zero to num_chipselects.
328  *	each slave has a chipselect signal, but it's common that not
329  *	every chipselect is connected to a slave.
330  * @dma_alignment: SPI controller constraint on DMA buffers alignment.
335  *	supported. If set, the SPI core will reject any transfer with an
341  * @slave: indicates that this is an SPI slave controller
347  * @bus_lock_spinlock: spinlock for SPI bus locking
349  * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use
351  *	device's SPI controller; protocol code may call this.  This
355  * @set_cs_timing: optional hook for SPI devices to request SPI master
359  * @cleanup: frees controller-specific state
367  * @cur_msg: the currently in-flight message
369  *                    in-flight message
400  *                  - return 0 if the transfer is finished,
401  *                  - return 1 if the transfer is still in progress. When
410  * @mem_ops: optimized/dedicated operations for interactions with SPI memory.
414  * @slave_abort: abort the ongoing transfer request on an SPI slave controller
421  *	CS number. Any individual value may be -ENOENT for CS lines that
422  *	are not GPIOs (driven by the SPI controller itself). Use the cs_gpiods
426  *	are not GPIOs (driven by the SPI controller itself).
427  * @use_gpio_descriptors: Turns on the code in the SPI core to parse and grab
430  *	and SPI devices will have the cs_gpiod assigned rather than cs_gpio.
432  *	fill in this field with the first unused native CS, to be used by SPI
440  * @dummy_rx: dummy receive buffer for full-duplex devices
441  * @dummy_tx: dummy transmit buffer for full-duplex devices
446  *	time snapshot in @spi_transfer->ptp_sts as close as possible to the
447  *	moment in time when @spi_transfer->ptp_sts_word_pre and
448  *	@spi_transfer->ptp_sts_word_post were transmitted.
449  *	If the driver does not set this, the SPI core takes the snapshot as
450  *	close to the driver hand-over as possible.
455  * Each SPI controller can communicate with one or more @spi_device
461  * The driver for an SPI controller manages access to those devices through
463  * an SPI slave device.  For each such message it queues, it calls the
472 	 * board-specific.  usually that simplifies to being SOC-specific.
473 	 * example:  one SOC has three SPI controllers, numbered 0..2,
474 	 * and one board's schematics might show it using SPI-2.  software
480 	 * might use board-specific GPIOs.
484 	/* some SPI controllers pose alignment requirements on DMAable
497 #define SPI_BPW_MASK(bits) BIT((bits) - 1)
498 #define SPI_BPW_RANGE_MASK(min, max) GENMASK((max) - 1, (min) - 1)
512 #define SPI_MASTER_GPIO_SS		BIT(5)	/* GPIO CS must select slave */
514 	/* flag indicating this is an SPI slave controller */
515 	bool			slave;  member
521 	size_t (*max_transfer_size)(struct spi_device *spi);
522 	size_t (*max_message_size)(struct spi_device *spi);
527 	/* lock and mutex for SPI bus locking */
531 	/* flag indicating that the SPI bus is locked for exclusive use */
534 	/* Setup mode and clock, etc (spi driver may call many times).
540 	int			(*setup)(struct spi_device *spi);
543 	 * set_cs_timing() method is for SPI controllers that supports
546 	 * This hook allows SPI client drivers to request SPI controllers
550 	int (*set_cs_timing)(struct spi_device *spi, struct spi_delay *setup,
557 	 * + For now there's no remove-from-queue operation, or
569 	 * + The message transfers use clock and SPI mode parameters
572 	int			(*transfer)(struct spi_device *spi,
576 	void			(*cleanup)(struct spi_device *spi);
586 					   struct spi_device *spi,
593 	 * Over time we expect SPI drivers to be phased over to this API.
628 	void (*set_cs)(struct spi_device *spi, bool enable);
629 	int (*transfer_one)(struct spi_controller *ctlr, struct spi_device *spi,
634 	/* Optimized handlers for SPI memory-like operations. */
663 	 * Driver sets this field to indicate it is able to snapshot SPI
674 	return dev_get_drvdata(&ctlr->dev);  in spi_controller_get_devdata()
680 	dev_set_drvdata(&ctlr->dev, data);  in spi_controller_set_devdata()
685 	if (!ctlr || !get_device(&ctlr->dev))  in spi_controller_get()
693 		put_device(&ctlr->dev);  in spi_controller_put()
698 	return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->slave;  in spi_controller_is_slave()
718 /* the spi driver core manages memory for the spi_controller classdev */
720 						unsigned int size, bool slave);
739 						   bool slave);
764  * SPI resource management while processing a SPI message
772  * struct spi_res - spi resource management structure
775  * @data:    extra data allocated for the specific use-case
777  * this is based on ideas from devres, but focused on life-cycle
786 extern void *spi_res_alloc(struct spi_device *spi,
795 /*---------------------------------------------------------------------------*/
798  * I/O INTERFACE between SPI controller and protocol drivers
806  * pointer.  (This is unlike most types of I/O API, because SPI hardware
815  * struct spi_transfer - a read/write buffer pair
816  * @tx_buf: data to be written (dma-safe memory), or NULL
817  * @rx_buf: data to be read (dma-safe memory), or NULL
840  * @effective_speed_hz: the effective SCK-speed that was used to
841  *      transfer this transfer. Set to 0 if the spi bus driver does
847  *	within @tx_buf for which the SPI device is requesting that the time
848  *	snapshot for this transfer begins. Upon completing the SPI transfer,
857  *	purposefully (instead of setting to spi_transfer->len - 1) to denote
858  *	that a transfer-level snapshot taken from within the driver may still
860  * @ptp_sts: Pointer to a memory location held by the SPI slave device where a
865  *	The timestamp must represent the time at which the SPI slave device has
870  * @error: Error status logged by spi controller driver.
872  * SPI transfers always write the same number of bytes as they read.
885  * In-memory data values are always in native CPU byte order, translated
886  * from the wire byte order (big-endian except with SPI_LSB_FIRST).  So
890  * When the word size of the SPI transfer is not a power-of-two multiple
891  * of eight bits, those in-memory words include extra bits.  In-memory
892  * words are always seen by protocol drivers as right-justified, so the
895  * All SPI transfers start with the relevant chipselect active.  Normally
906  * stay selected until the next transfer.  On multi-device SPI busses
915  * When SPI can transfer in 1x,2x or 4x. It can get this transfer information
916  * from device through @tx_nbits and @rx_nbits. In Bi-direction, these
922  * Zero-initialize every field you don't set up explicitly, to
930 	 *   spi_message.is_dma_mapped reports a pre-existing mapping
970  * struct spi_message - one multi-segment SPI transaction
972  * @spi: SPI device to which the transaction is queued
983  * @resources: for resource management when the spi message is processed
987  * in the sense that no other spi_message may use that SPI bus until that
995  * Zero-initialize every field you don't set up explicitly, to
1002 	struct spi_device	*spi;  member
1011 	 * Some controller drivers (message-at-a-time queue processing)
1013 	 * others (with multi-message pipelines) could need a flag to
1031 	/* list of spi_res reources when the spi message is processed */
1037 	INIT_LIST_HEAD(&m->transfers);  in spi_message_init_no_memset()
1038 	INIT_LIST_HEAD(&m->resources);  in spi_message_init_no_memset()
1050 	list_add_tail(&t->transfer_list, &m->transfers);  in spi_message_add_tail()
1056 	list_del(&t->transfer_list);  in spi_transfer_del()
1064 	if (t->delay_usecs) {  in spi_transfer_delay_exec()
1065 		d.value = t->delay_usecs;  in spi_transfer_delay_exec()
1070 	return spi_delay_exec(&t->delay, t);  in spi_transfer_delay_exec()
1074  * spi_message_init_with_transfers - Initialize spi_message and append transfers
1076  * @xfers: An array of spi transfers
1120 extern int spi_set_cs_timing(struct spi_device *spi,
1125 extern int spi_setup(struct spi_device *spi);
1126 extern int spi_async(struct spi_device *spi, struct spi_message *message);
1127 extern int spi_async_locked(struct spi_device *spi,
1129 extern int spi_slave_abort(struct spi_device *spi);
1132 spi_max_message_size(struct spi_device *spi)  in spi_max_message_size()  argument
1134 	struct spi_controller *ctlr = spi->controller;  in spi_max_message_size()
1136 	if (!ctlr->max_message_size)  in spi_max_message_size()
1138 	return ctlr->max_message_size(spi);  in spi_max_message_size()
1142 spi_max_transfer_size(struct spi_device *spi)  in spi_max_transfer_size()  argument
1144 	struct spi_controller *ctlr = spi->controller;  in spi_max_transfer_size()
1146 	size_t msg_max = spi_max_message_size(spi);  in spi_max_transfer_size()
1148 	if (ctlr->max_transfer_size)  in spi_max_transfer_size()
1149 		tr_max = ctlr->max_transfer_size(spi);  in spi_max_transfer_size()
1156  * spi_is_bpw_supported - Check if bits per word is supported
1157  * @spi: SPI device
1160  * This function checks to see if the SPI controller supports @bpw.
1165 static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw)  in spi_is_bpw_supported()  argument
1167 	u32 bpw_mask = spi->master->bits_per_word_mask;  in spi_is_bpw_supported()
1175 /*---------------------------------------------------------------------------*/
1177 /* SPI transfer replacement methods which make use of spi_res */
1184  * struct spi_replaced_transfers - structure describing the spi_transfer
1193  *                      are to get re-inserted
1195  * @inserted_transfers: array of spi_transfers of array-size @inserted,
1220 /*---------------------------------------------------------------------------*/
1222 /* SPI transfer transformation methods */
1229 /*---------------------------------------------------------------------------*/
1231 /* All these synchronous SPI transfer routines are utilities layered
1236 extern int spi_sync(struct spi_device *spi, struct spi_message *message);
1237 extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
1242  * spi_sync_transfer - synchronous SPI data transfer
1243  * @spi: device with which data will be exchanged
1248  * Does a synchronous SPI data transfer of the given spi_transfer array.
1255 spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers,  in spi_sync_transfer()  argument
1262 	return spi_sync(spi, &msg);  in spi_sync_transfer()
1266  * spi_write - SPI synchronous write
1267  * @spi: device to which data will be written
1278 spi_write(struct spi_device *spi, const void *buf, size_t len)  in spi_write()  argument
1285 	return spi_sync_transfer(spi, &t, 1);  in spi_write()
1289  * spi_read - SPI synchronous read
1290  * @spi: device from which data will be read
1301 spi_read(struct spi_device *spi, void *buf, size_t len)  in spi_read()  argument
1308 	return spi_sync_transfer(spi, &t, 1);  in spi_read()
1312 extern int spi_write_then_read(struct spi_device *spi,
1317  * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
1318  * @spi: device with which data will be exchanged
1327 static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)  in spi_w8r8()  argument
1332 	status = spi_write_then_read(spi, &cmd, 1, &result, 1);  in spi_w8r8()
1339  * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
1340  * @spi: device with which data will be exchanged
1344  * The number is returned in wire-order, which is at least sometimes
1345  * big-endian.
1352 static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)  in spi_w8r16()  argument
1357 	status = spi_write_then_read(spi, &cmd, 1, &result, 2);  in spi_w8r16()
1364  * spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read
1365  * @spi: device with which data will be exchanged
1370  * convert the read 16 bit data word from big-endian to native endianness.
1377 static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd)  in spi_w8r16be()  argument
1383 	status = spi_write_then_read(spi, &cmd, 1, &result, 2);  in spi_w8r16be()
1390 /*---------------------------------------------------------------------------*/
1393  * INTERFACE between board init code and SPI infrastructure.
1395  * No SPI driver ever sees these SPI device table segments, but
1396  * it's how the SPI core (or adapters that get hotplugged) grows
1399  * As a rule, SPI devices can't be probed.  Instead, board init code
1403  * parport adapters, or microcontrollers acting as USB-to-SPI bridges.
1407  * struct spi_board_info - board-specific template for a SPI device
1410  *	data stored there is driver-specific.
1416  *	from the chip datasheet and board-specific signal quality issues.
1425  * When adding new SPI devices to the device tree, these structures serve
1431  * be stored in tables of board-specific device descriptors, which are
1474 	 *  - quirks like clock rate mattering when not selected
1482 /* board init code may ignore whether SPI is configured or not */
1503 spi_add_device(struct spi_device *spi);
1508 extern void spi_unregister_device(struct spi_device *spi);
1516 	return list_is_last(&xfer->transfer_list, &ctlr->cur_msg->transfers);  in spi_transfer_is_last()