/* SPDX-License-Identifier: GPL-2.0-or-later * * Copyright (C) 2005 David Brownell */ #ifndef __LINUX_SPI_H #define __LINUX_SPI_H #include <linux/acpi.h> #include <linux/bits.h> #include <linux/completion.h> #include <linux/device.h> #include <linux/gpio/consumer.h> #include <linux/kthread.h> #include <linux/mod_devicetable.h> #include <linux/overflow.h> #include <linux/scatterlist.h> #include <linux/slab.h> #include <linux/u64_stats_sync.h> #include <uapi/linux/spi/spi.h> /* Max no. of CS supported per spi device */ #define SPI_CS_CNT_MAX … struct dma_chan; struct software_node; struct ptp_system_timestamp; struct spi_controller; struct spi_transfer; struct spi_controller_mem_ops; struct spi_controller_mem_caps; struct spi_message; /* * INTERFACES between SPI master-side drivers and SPI slave protocol handlers, * and SPI infrastructure. */ extern const struct bus_type spi_bus_type; /** * struct spi_statistics - statistics for spi transfers * @syncp: seqcount to protect members in this struct for per-cpu update * on 32-bit systems * * @messages: number of spi-messages handled * @transfers: number of spi_transfers handled * @errors: number of errors during spi_transfer * @timedout: number of timeouts during spi_transfer * * @spi_sync: number of times spi_sync is used * @spi_sync_immediate: * number of times spi_sync is executed immediately * in calling context without queuing and scheduling * @spi_async: number of times spi_async is used * * @bytes: number of bytes transferred to/from device * @bytes_tx: number of bytes sent to device * @bytes_rx: number of bytes received from device * * @transfer_bytes_histo: * transfer bytes histogram * * @transfers_split_maxsize: * number of transfers that have been split because of * maxsize limit */ struct spi_statistics { … }; #define SPI_STATISTICS_ADD_TO_FIELD(pcpu_stats, field, count) … #define SPI_STATISTICS_INCREMENT_FIELD(pcpu_stats, field) … /** * struct spi_delay - SPI delay information * @value: Value for the delay * @unit: Unit for the delay */ struct spi_delay { … }; extern int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer); extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer); extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg, struct spi_transfer *xfer); /** * struct spi_device - Controller side proxy for an SPI slave device * @dev: Driver model representation of the device. * @controller: SPI controller used with the device. * @max_speed_hz: Maximum clock rate to be used with this chip * (on this board); may be changed by the device's driver. * The spi_transfer.speed_hz can override this for each transfer. * @chip_select: Array of physical chipselect, spi->chipselect[i] gives * the corresponding physical CS for logical CS i. * @mode: The spi mode defines how data is clocked out and in. * This may be changed by the device's driver. * The "active low" default for chipselect mode can be overridden * (by specifying SPI_CS_HIGH) as can the "MSB first" default for * each word in a transfer (by specifying SPI_LSB_FIRST). * @bits_per_word: Data transfers involve one or more words; word sizes * like eight or 12 bits are common. In-memory wordsizes are * powers of two bytes (e.g. 20 bit samples use 32 bits). * This may be changed by the device's driver, or left at the * default (0) indicating protocol words are eight bit bytes. * The spi_transfer.bits_per_word can override this for each transfer. * @rt: Make the pump thread real time priority. * @irq: Negative, or the number passed to request_irq() to receive * interrupts from this device. * @controller_state: Controller's runtime state * @controller_data: Board-specific definitions for controller, such as * FIFO initialization parameters; from board_info.controller_data * @modalias: Name of the driver to use with this device, or an alias * for that name. This appears in the sysfs "modalias" attribute * for driver coldplugging, and in uevents used for hotplugging * @driver_override: If the name of a driver is written to this attribute, then * the device will bind to the named driver and only the named driver. * Do not set directly, because core frees it; use driver_set_override() to * set or clear it. * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect lines * (optional, NULL when not using a GPIO line) * @word_delay: delay to be inserted between consecutive * words of a transfer * @cs_setup: delay to be introduced by the controller after CS is asserted * @cs_hold: delay to be introduced by the controller before CS is deasserted * @cs_inactive: delay to be introduced by the controller after CS is * deasserted. If @cs_change_delay is used from @spi_transfer, then the * two delays will be added up. * @pcpu_statistics: statistics for the spi_device * @cs_index_mask: Bit mask of the active chipselect(s) in the chipselect array * * A @spi_device is used to interchange data between an SPI slave * (usually a discrete chip) and CPU memory. * * In @dev, the platform_data is used to hold information about this * device that's meaningful to the device's protocol driver, but not * to its controller. One example might be an identifier for a chip * variant with slightly different functionality; another might be * information about how this particular board wires the chip's pins. */ struct spi_device { … }; /* Make sure that SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK don't overlap */ static_assert(…); static inline struct spi_device *to_spi_device(const struct device *dev) { … } /* Most drivers won't need to care about device refcounting */ static inline struct spi_device *spi_dev_get(struct spi_device *spi) { … } static inline void spi_dev_put(struct spi_device *spi) { … } /* ctldata is for the bus_controller driver's runtime state */ static inline void *spi_get_ctldata(const struct spi_device *spi) { … } static inline void spi_set_ctldata(struct spi_device *spi, void *state) { … } /* Device driver data */ static inline void spi_set_drvdata(struct spi_device *spi, void *data) { … } static inline void *spi_get_drvdata(const struct spi_device *spi) { … } static inline u8 spi_get_chipselect(const struct spi_device *spi, u8 idx) { … } static inline void spi_set_chipselect(struct spi_device *spi, u8 idx, u8 chipselect) { … } static inline struct gpio_desc *spi_get_csgpiod(const struct spi_device *spi, u8 idx) { … } static inline void spi_set_csgpiod(struct spi_device *spi, u8 idx, struct gpio_desc *csgpiod) { … } static inline bool spi_is_csgpiod(struct spi_device *spi) { … } /** * struct spi_driver - Host side "protocol" driver * @id_table: List of SPI devices supported by this driver * @probe: Binds this driver to the SPI device. Drivers can verify * that the device is actually present, and may need to configure * characteristics (such as bits_per_word) which weren't needed for * the initial configuration done during system setup. * @remove: Unbinds this driver from the SPI device * @shutdown: Standard shutdown callback used during system state * transitions such as powerdown/halt and kexec * @driver: SPI device drivers should initialize the name and owner * field of this structure. * * This represents the kind of device driver that uses SPI messages to * interact with the hardware at the other end of a SPI link. It's called * a "protocol" driver because it works through messages rather than talking * directly to SPI hardware (which is what the underlying SPI controller * driver does to pass those messages). These protocols are defined in the * specification for the device(s) supported by the driver. * * As a rule, those device protocols represent the lowest level interface * supported by a driver, and it will support upper level interfaces too. * Examples of such upper levels include frameworks like MTD, networking, * MMC, RTC, filesystem character device nodes, and hardware monitoring. */ struct spi_driver { … }; #define to_spi_driver(__drv) … extern int __spi_register_driver(struct module *owner, struct spi_driver *sdrv); /** * spi_unregister_driver - reverse effect of spi_register_driver * @sdrv: the driver to unregister * Context: can sleep */ static inline void spi_unregister_driver(struct spi_driver *sdrv) { … } extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 chip_select); /* Use a define to avoid include chaining to get THIS_MODULE */ #define spi_register_driver(driver) … /** * module_spi_driver() - Helper macro for registering a SPI driver * @__spi_driver: spi_driver struct * * Helper macro for SPI drivers which do not do anything special in module * init/exit. This eliminates a lot of boilerplate. Each module may only * use this macro once, and calling it replaces module_init() and module_exit() */ #define module_spi_driver(__spi_driver) … /** * struct spi_controller - interface to SPI master or slave controller * @dev: device interface to this driver * @list: link with the global spi_controller list * @bus_num: board-specific (and often SOC-specific) identifier for a * given SPI controller. * @num_chipselect: chipselects are used to distinguish individual * SPI slaves, and are numbered from zero to num_chipselects. * each slave has a chipselect signal, but it's common that not * every chipselect is connected to a slave. * @dma_alignment: SPI controller constraint on DMA buffers alignment. * @mode_bits: flags understood by this controller driver * @buswidth_override_bits: flags to override for this controller driver * @bits_per_word_mask: A mask indicating which values of bits_per_word are * supported by the driver. Bit n indicates that a bits_per_word n+1 is * supported. If set, the SPI core will reject any transfer with an * unsupported bits_per_word. If not set, this value is simply ignored, * and it's up to the individual driver to perform any validation. * @min_speed_hz: Lowest supported transfer speed * @max_speed_hz: Highest supported transfer speed * @flags: other constraints relevant to this driver * @slave: indicates that this is an SPI slave controller * @target: indicates that this is an SPI target controller * @devm_allocated: whether the allocation of this struct is devres-managed * @max_transfer_size: function that returns the max transfer size for * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used. * @max_message_size: function that returns the max message size for * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used. * @io_mutex: mutex for physical bus access * @add_lock: mutex to avoid adding devices to the same chipselect * @bus_lock_spinlock: spinlock for SPI bus locking * @bus_lock_mutex: mutex for exclusion of multiple callers * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use * @setup: updates the device mode and clocking records used by a * device's SPI controller; protocol code may call this. This * must fail if an unrecognized or unsupported mode is requested. * It's always safe to call this unless transfers are pending on * the device whose settings are being modified. * @set_cs_timing: optional hook for SPI devices to request SPI master * controller for configuring specific CS setup time, hold time and inactive * delay interms of clock counts * @transfer: adds a message to the controller's transfer queue. * @cleanup: frees controller-specific state * @can_dma: determine whether this controller supports DMA * @dma_map_dev: device which can be used for DMA mapping * @cur_rx_dma_dev: device which is currently used for RX DMA mapping * @cur_tx_dma_dev: device which is currently used for TX DMA mapping * @queued: whether this controller is providing an internal message queue * @kworker: pointer to thread struct for message pump * @pump_messages: work struct for scheduling work to the message pump * @queue_lock: spinlock to synchronise access to message queue * @queue: message queue * @cur_msg: the currently in-flight message * @cur_msg_completion: a completion for the current in-flight message * @cur_msg_incomplete: Flag used internally to opportunistically skip * the @cur_msg_completion. This flag is used to check if the driver has * already called spi_finalize_current_message(). * @cur_msg_need_completion: Flag used internally to opportunistically skip * the @cur_msg_completion. This flag is used to signal the context that * is running spi_finalize_current_message() that it needs to complete() * @fallback: fallback to PIO if DMA transfer return failure with * SPI_TRANS_FAIL_NO_START. * @last_cs_mode_high: was (mode & SPI_CS_HIGH) true on the last call to set_cs. * @last_cs: the last chip_select that is recorded by set_cs, -1 on non chip * selected * @last_cs_index_mask: bit mask the last chip selects that were used * @xfer_completion: used by core transfer_one_message() * @busy: message pump is busy * @running: message pump is running * @rt: whether this queue is set to run as a realtime task * @auto_runtime_pm: the core should ensure a runtime PM reference is held * while the hardware is prepared, using the parent * device for the spidev * @max_dma_len: Maximum length of a DMA transfer for the device. * @prepare_transfer_hardware: a message will soon arrive from the queue * so the subsystem requests the driver to prepare the transfer hardware * by issuing this call * @transfer_one_message: the subsystem calls the driver to transfer a single * message while queuing transfers that arrive in the meantime. When the * driver is finished with this message, it must call * spi_finalize_current_message() so the subsystem can issue the next * message * @unprepare_transfer_hardware: there are currently no more messages on the * queue so the subsystem notifies the driver that it may relax the * hardware by issuing this call * * @set_cs: set the logic level of the chip select line. May be called * from interrupt context. * @optimize_message: optimize the message for reuse * @unoptimize_message: release resources allocated by optimize_message * @prepare_message: set up the controller to transfer a single message, * for example doing DMA mapping. Called from threaded * context. * @transfer_one: transfer a single spi_transfer. * * - return 0 if the transfer is finished, * - return 1 if the transfer is still in progress. When * the driver is finished with this transfer it must * call spi_finalize_current_transfer() so the subsystem * can issue the next transfer. If the transfer fails, the * driver must set the flag SPI_TRANS_FAIL_IO to * spi_transfer->error first, before calling * spi_finalize_current_transfer(). * Note: transfer_one and transfer_one_message are mutually * exclusive; when both are set, the generic subsystem does * not call your transfer_one callback. * @handle_err: the subsystem calls the driver to handle an error that occurs * in the generic implementation of transfer_one_message(). * @mem_ops: optimized/dedicated operations for interactions with SPI memory. * This field is optional and should only be implemented if the * controller has native support for memory like operations. * @mem_caps: controller capabilities for the handling of memory operations. * @unprepare_message: undo any work done by prepare_message(). * @slave_abort: abort the ongoing transfer request on an SPI slave controller * @target_abort: abort the ongoing transfer request on an SPI target controller * @cs_gpiods: Array of GPIO descriptors to use as chip select lines; one per CS * number. Any individual value may be NULL for CS lines that * are not GPIOs (driven by the SPI controller itself). * @use_gpio_descriptors: Turns on the code in the SPI core to parse and grab * GPIO descriptors. This will fill in @cs_gpiods and SPI devices will have * the cs_gpiod assigned if a GPIO line is found for the chipselect. * @unused_native_cs: When cs_gpiods is used, spi_register_controller() will * fill in this field with the first unused native CS, to be used by SPI * controller drivers that need to drive a native CS when using GPIO CS. * @max_native_cs: When cs_gpiods is used, and this field is filled in, * spi_register_controller() will validate all native CS (including the * unused native CS) against this value. * @pcpu_statistics: statistics for the spi_controller * @dma_tx: DMA transmit channel * @dma_rx: DMA receive channel * @dummy_rx: dummy receive buffer for full-duplex devices * @dummy_tx: dummy transmit buffer for full-duplex devices * @fw_translate_cs: If the boot firmware uses different numbering scheme * what Linux expects, this optional hook can be used to translate * between the two. * @ptp_sts_supported: If the driver sets this to true, it must provide a * time snapshot in @spi_transfer->ptp_sts as close as possible to the * moment in time when @spi_transfer->ptp_sts_word_pre and * @spi_transfer->ptp_sts_word_post were transmitted. * If the driver does not set this, the SPI core takes the snapshot as * close to the driver hand-over as possible. * @irq_flags: Interrupt enable state during PTP system timestamping * @queue_empty: signal green light for opportunistically skipping the queue * for spi_sync transfers. * @must_async: disable all fast paths in the core * @defer_optimize_message: set to true if controller cannot pre-optimize messages * and needs to defer the optimization step until the message is actually * being transferred * * Each SPI controller can communicate with one or more @spi_device * children. These make a small bus, sharing MOSI, MISO and SCK signals * but not chip select signals. Each device may be configured to use a * different clock rate, since those shared signals are ignored unless * the chip is selected. * * The driver for an SPI controller manages access to those devices through * a queue of spi_message transactions, copying data between CPU memory and * an SPI slave device. For each such message it queues, it calls the * message's completion function when the transaction completes. */ struct spi_controller { … }; static inline void *spi_controller_get_devdata(struct spi_controller *ctlr) { … } static inline void spi_controller_set_devdata(struct spi_controller *ctlr, void *data) { … } static inline struct spi_controller *spi_controller_get(struct spi_controller *ctlr) { … } static inline void spi_controller_put(struct spi_controller *ctlr) { … } static inline bool spi_controller_is_slave(struct spi_controller *ctlr) { … } static inline bool spi_controller_is_target(struct spi_controller *ctlr) { … } /* PM calls that need to be issued by the driver */ extern int spi_controller_suspend(struct spi_controller *ctlr); extern int spi_controller_resume(struct spi_controller *ctlr); /* Calls the driver make to interact with the message queue */ extern struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr); extern void spi_finalize_current_message(struct spi_controller *ctlr); extern void spi_finalize_current_transfer(struct spi_controller *ctlr); /* Helper calls for driver to timestamp transfer */ void spi_take_timestamp_pre(struct spi_controller *ctlr, struct spi_transfer *xfer, size_t progress, bool irqs_off); void spi_take_timestamp_post(struct spi_controller *ctlr, struct spi_transfer *xfer, size_t progress, bool irqs_off); /* The SPI driver core manages memory for the spi_controller classdev */ extern struct spi_controller *__spi_alloc_controller(struct device *host, unsigned int size, bool slave); static inline struct spi_controller *spi_alloc_master(struct device *host, unsigned int size) { … } static inline struct spi_controller *spi_alloc_slave(struct device *host, unsigned int size) { … } static inline struct spi_controller *spi_alloc_host(struct device *dev, unsigned int size) { … } static inline struct spi_controller *spi_alloc_target(struct device *dev, unsigned int size) { … } struct spi_controller *__devm_spi_alloc_controller(struct device *dev, unsigned int size, bool slave); static inline struct spi_controller *devm_spi_alloc_master(struct device *dev, unsigned int size) { … } static inline struct spi_controller *devm_spi_alloc_slave(struct device *dev, unsigned int size) { … } static inline struct spi_controller *devm_spi_alloc_host(struct device *dev, unsigned int size) { … } static inline struct spi_controller *devm_spi_alloc_target(struct device *dev, unsigned int size) { … } extern int spi_register_controller(struct spi_controller *ctlr); extern int devm_spi_register_controller(struct device *dev, struct spi_controller *ctlr); extern void spi_unregister_controller(struct spi_controller *ctlr); #if IS_ENABLED(CONFIG_ACPI) extern struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev); extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, struct acpi_device *adev, int index); int acpi_spi_count_resources(struct acpi_device *adev); #endif /* * SPI resource management while processing a SPI message */ spi_res_release_t; /** * struct spi_res - SPI resource management structure * @entry: list entry * @release: release code called prior to freeing this resource * @data: extra data allocated for the specific use-case * * This is based on ideas from devres, but focused on life-cycle * management during spi_message processing. */ struct spi_res { … }; /*---------------------------------------------------------------------------*/ /* * I/O INTERFACE between SPI controller and protocol drivers * * Protocol drivers use a queue of spi_messages, each transferring data * between the controller and memory buffers. * * The spi_messages themselves consist of a series of read+write transfer * segments. Those segments always read the same number of bits as they * write; but one or the other is easily ignored by passing a NULL buffer * pointer. (This is unlike most types of I/O API, because SPI hardware * is full duplex.) * * NOTE: Allocation of spi_transfer and spi_message memory is entirely * up to the protocol driver, which guarantees the integrity of both (as * well as the data buffers) for as long as the message is queued. */ /** * struct spi_transfer - a read/write buffer pair * @tx_buf: data to be written (DMA-safe memory), or NULL * @rx_buf: data to be read (DMA-safe memory), or NULL * @tx_dma: DMA address of tx_buf, currently not for client use * @rx_dma: DMA address of rx_buf, currently not for client use * @tx_nbits: number of bits used for writing. If 0 the default * (SPI_NBITS_SINGLE) is used. * @rx_nbits: number of bits used for reading. If 0 the default * (SPI_NBITS_SINGLE) is used. * @len: size of rx and tx buffers (in bytes) * @speed_hz: Select a speed other than the device default for this * transfer. If 0 the default (from @spi_device) is used. * @bits_per_word: select a bits_per_word other than the device default * for this transfer. If 0 the default (from @spi_device) is used. * @dummy_data: indicates transfer is dummy bytes transfer. * @cs_off: performs the transfer with chipselect off. * @cs_change: affects chipselect after this transfer completes * @cs_change_delay: delay between cs deassert and assert when * @cs_change is set and @spi_transfer is not the last in @spi_message * @delay: delay to be introduced after this transfer before * (optionally) changing the chipselect status, then starting * the next transfer or completing this @spi_message. * @word_delay: inter word delay to be introduced after each word size * (set by bits_per_word) transmission. * @effective_speed_hz: the effective SCK-speed that was used to * transfer this transfer. Set to 0 if the SPI bus driver does * not support it. * @transfer_list: transfers are sequenced through @spi_message.transfers * @tx_sg_mapped: If true, the @tx_sg is mapped for DMA * @rx_sg_mapped: If true, the @rx_sg is mapped for DMA * @tx_sg: Scatterlist for transmit, currently not for client use * @rx_sg: Scatterlist for receive, currently not for client use * @ptp_sts_word_pre: The word (subject to bits_per_word semantics) offset * within @tx_buf for which the SPI device is requesting that the time * snapshot for this transfer begins. Upon completing the SPI transfer, * this value may have changed compared to what was requested, depending * on the available snapshotting resolution (DMA transfer, * @ptp_sts_supported is false, etc). * @ptp_sts_word_post: See @ptp_sts_word_post. The two can be equal (meaning * that a single byte should be snapshotted). * If the core takes care of the timestamp (if @ptp_sts_supported is false * for this controller), it will set @ptp_sts_word_pre to 0, and * @ptp_sts_word_post to the length of the transfer. This is done * purposefully (instead of setting to spi_transfer->len - 1) to denote * that a transfer-level snapshot taken from within the driver may still * be of higher quality. * @ptp_sts: Pointer to a memory location held by the SPI slave device where a * PTP system timestamp structure may lie. If drivers use PIO or their * hardware has some sort of assist for retrieving exact transfer timing, * they can (and should) assert @ptp_sts_supported and populate this * structure using the ptp_read_system_*ts helper functions. * The timestamp must represent the time at which the SPI slave device has * processed the word, i.e. the "pre" timestamp should be taken before * transmitting the "pre" word, and the "post" timestamp after receiving * transmit confirmation from the controller for the "post" word. * @timestamped: true if the transfer has been timestamped * @error: Error status logged by SPI controller driver. * * SPI transfers always write the same number of bytes as they read. * Protocol drivers should always provide @rx_buf and/or @tx_buf. * In some cases, they may also want to provide DMA addresses for * the data being transferred; that may reduce overhead, when the * underlying driver uses DMA. * * If the transmit buffer is NULL, zeroes will be shifted out * while filling @rx_buf. If the receive buffer is NULL, the data * shifted in will be discarded. Only "len" bytes shift out (or in). * It's an error to try to shift out a partial word. (For example, by * shifting out three bytes with word size of sixteen or twenty bits; * the former uses two bytes per word, the latter uses four bytes.) * * In-memory data values are always in native CPU byte order, translated * from the wire byte order (big-endian except with SPI_LSB_FIRST). So * for example when bits_per_word is sixteen, buffers are 2N bytes long * (@len = 2N) and hold N sixteen bit words in CPU byte order. * * When the word size of the SPI transfer is not a power-of-two multiple * of eight bits, those in-memory words include extra bits. In-memory * words are always seen by protocol drivers as right-justified, so the * undefined (rx) or unused (tx) bits are always the most significant bits. * * All SPI transfers start with the relevant chipselect active. Normally * it stays selected until after the last transfer in a message. Drivers * can affect the chipselect signal using cs_change. * * (i) If the transfer isn't the last one in the message, this flag is * used to make the chipselect briefly go inactive in the middle of the * message. Toggling chipselect in this way may be needed to terminate * a chip command, letting a single spi_message perform all of group of * chip transactions together. * * (ii) When the transfer is the last one in the message, the chip may * stay selected until the next transfer. On multi-device SPI busses * with nothing blocking messages going to other devices, this is just * a performance hint; starting a message to another device deselects * this one. But in other cases, this can be used to ensure correctness. * Some devices need protocol transactions to be built from a series of * spi_message submissions, where the content of one message is determined * by the results of previous messages and where the whole transaction * ends when the chipselect goes inactive. * * When SPI can transfer in 1x,2x or 4x. It can get this transfer information * from device through @tx_nbits and @rx_nbits. In Bi-direction, these * two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x) * SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer. * * The code that submits an spi_message (and its spi_transfers) * to the lower layers is responsible for managing its memory. * Zero-initialize every field you don't set up explicitly, to * insulate against future API updates. After you submit a message * and its transfers, ignore them until its completion callback. */ struct spi_transfer { … }; /** * struct spi_message - one multi-segment SPI transaction * @transfers: list of transfer segments in this transaction * @spi: SPI device to which the transaction is queued * @pre_optimized: peripheral driver pre-optimized the message * @optimized: the message is in the optimized state * @prepared: spi_prepare_message was called for the this message * @status: zero for success, else negative errno * @complete: called to report transaction completions * @context: the argument to complete() when it's called * @frame_length: the total number of bytes in the message * @actual_length: the total number of bytes that were transferred in all * successful segments * @queue: for use by whichever driver currently owns the message * @state: for use by whichever driver currently owns the message * @opt_state: for use by whichever driver currently owns the message * @resources: for resource management when the SPI message is processed * * A @spi_message is used to execute an atomic sequence of data transfers, * each represented by a struct spi_transfer. The sequence is "atomic" * in the sense that no other spi_message may use that SPI bus until that * sequence completes. On some systems, many such sequences can execute as * a single programmed DMA transfer. On all systems, these messages are * queued, and might complete after transactions to other devices. Messages * sent to a given spi_device are always executed in FIFO order. * * The code that submits an spi_message (and its spi_transfers) * to the lower layers is responsible for managing its memory. * Zero-initialize every field you don't set up explicitly, to * insulate against future API updates. After you submit a message * and its transfers, ignore them until its completion callback. */ struct spi_message { … }; static inline void spi_message_init_no_memset(struct spi_message *m) { … } static inline void spi_message_init(struct spi_message *m) { … } static inline void spi_message_add_tail(struct spi_transfer *t, struct spi_message *m) { … } static inline void spi_transfer_del(struct spi_transfer *t) { … } static inline int spi_transfer_delay_exec(struct spi_transfer *t) { … } /** * spi_message_init_with_transfers - Initialize spi_message and append transfers * @m: spi_message to be initialized * @xfers: An array of SPI transfers * @num_xfers: Number of items in the xfer array * * This function initializes the given spi_message and adds each spi_transfer in * the given array to the message. */ static inline void spi_message_init_with_transfers(struct spi_message *m, struct spi_transfer *xfers, unsigned int num_xfers) { … } /* * It's fine to embed message and transaction structures in other data * structures so long as you don't free them while they're in use. */ static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags) { … } static inline void spi_message_free(struct spi_message *m) { … } extern int spi_optimize_message(struct spi_device *spi, struct spi_message *msg); extern void spi_unoptimize_message(struct spi_message *msg); extern int devm_spi_optimize_message(struct device *dev, struct spi_device *spi, struct spi_message *msg); extern int spi_setup(struct spi_device *spi); extern int spi_async(struct spi_device *spi, struct spi_message *message); extern int spi_slave_abort(struct spi_device *spi); extern int spi_target_abort(struct spi_device *spi); static inline size_t spi_max_message_size(struct spi_device *spi) { … } static inline size_t spi_max_transfer_size(struct spi_device *spi) { … } /** * spi_is_bpw_supported - Check if bits per word is supported * @spi: SPI device * @bpw: Bits per word * * This function checks to see if the SPI controller supports @bpw. * * Returns: * True if @bpw is supported, false otherwise. */ static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw) { … } /** * spi_controller_xfer_timeout - Compute a suitable timeout value * @ctlr: SPI device * @xfer: Transfer descriptor * * Compute a relevant timeout value for the given transfer. We derive the time * that it would take on a single data line and take twice this amount of time * with a minimum of 500ms to avoid false positives on loaded systems. * * Returns: Transfer timeout value in milliseconds. */ static inline unsigned int spi_controller_xfer_timeout(struct spi_controller *ctlr, struct spi_transfer *xfer) { … } /*---------------------------------------------------------------------------*/ /* SPI transfer replacement methods which make use of spi_res */ struct spi_replaced_transfers; spi_replaced_release_t; /** * struct spi_replaced_transfers - structure describing the spi_transfer * replacements that have occurred * so that they can get reverted * @release: some extra release code to get executed prior to * releasing this structure * @extradata: pointer to some extra data if requested or NULL * @replaced_transfers: transfers that have been replaced and which need * to get restored * @replaced_after: the transfer after which the @replaced_transfers * are to get re-inserted * @inserted: number of transfers inserted * @inserted_transfers: array of spi_transfers of array-size @inserted, * that have been replacing replaced_transfers * * Note: that @extradata will point to @inserted_transfers[@inserted] * if some extra allocation is requested, so alignment will be the same * as for spi_transfers. */ struct spi_replaced_transfers { … }; /*---------------------------------------------------------------------------*/ /* SPI transfer transformation methods */ extern int spi_split_transfers_maxsize(struct spi_controller *ctlr, struct spi_message *msg, size_t maxsize); extern int spi_split_transfers_maxwords(struct spi_controller *ctlr, struct spi_message *msg, size_t maxwords); /*---------------------------------------------------------------------------*/ /* * All these synchronous SPI transfer routines are utilities layered * over the core async transfer primitive. Here, "synchronous" means * they will sleep uninterruptibly until the async transfer completes. */ extern int spi_sync(struct spi_device *spi, struct spi_message *message); extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message); extern int spi_bus_lock(struct spi_controller *ctlr); extern int spi_bus_unlock(struct spi_controller *ctlr); /** * spi_sync_transfer - synchronous SPI data transfer * @spi: device with which data will be exchanged * @xfers: An array of spi_transfers * @num_xfers: Number of items in the xfer array * Context: can sleep * * Does a synchronous SPI data transfer of the given spi_transfer array. * * For more specific semantics see spi_sync(). * * Return: zero on success, else a negative error code. */ static inline int spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers, unsigned int num_xfers) { … } /** * spi_write - SPI synchronous write * @spi: device to which data will be written * @buf: data buffer * @len: data buffer size * Context: can sleep * * This function writes the buffer @buf. * Callable only from contexts that can sleep. * * Return: zero on success, else a negative error code. */ static inline int spi_write(struct spi_device *spi, const void *buf, size_t len) { … } /** * spi_read - SPI synchronous read * @spi: device from which data will be read * @buf: data buffer * @len: data buffer size * Context: can sleep * * This function reads the buffer @buf. * Callable only from contexts that can sleep. * * Return: zero on success, else a negative error code. */ static inline int spi_read(struct spi_device *spi, void *buf, size_t len) { … } /* This copies txbuf and rxbuf data; for small transfers only! */ extern int spi_write_then_read(struct spi_device *spi, const void *txbuf, unsigned n_tx, void *rxbuf, unsigned n_rx); /** * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read * @spi: device with which data will be exchanged * @cmd: command to be written before data is read back * Context: can sleep * * Callable only from contexts that can sleep. * * Return: the (unsigned) eight bit number returned by the * device, or else a negative error code. */ static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd) { … } /** * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read * @spi: device with which data will be exchanged * @cmd: command to be written before data is read back * Context: can sleep * * The number is returned in wire-order, which is at least sometimes * big-endian. * * Callable only from contexts that can sleep. * * Return: the (unsigned) sixteen bit number returned by the * device, or else a negative error code. */ static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd) { … } /** * spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read * @spi: device with which data will be exchanged * @cmd: command to be written before data is read back * Context: can sleep * * This function is similar to spi_w8r16, with the exception that it will * convert the read 16 bit data word from big-endian to native endianness. * * Callable only from contexts that can sleep. * * Return: the (unsigned) sixteen bit number returned by the device in CPU * endianness, or else a negative error code. */ static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd) { … } /*---------------------------------------------------------------------------*/ /* * INTERFACE between board init code and SPI infrastructure. * * No SPI driver ever sees these SPI device table segments, but * it's how the SPI core (or adapters that get hotplugged) grows * the driver model tree. * * As a rule, SPI devices can't be probed. Instead, board init code * provides a table listing the devices which are present, with enough * information to bind and set up the device's driver. There's basic * support for non-static configurations too; enough to handle adding * parport adapters, or microcontrollers acting as USB-to-SPI bridges. */ /** * struct spi_board_info - board-specific template for a SPI device * @modalias: Initializes spi_device.modalias; identifies the driver. * @platform_data: Initializes spi_device.platform_data; the particular * data stored there is driver-specific. * @swnode: Software node for the device. * @controller_data: Initializes spi_device.controller_data; some * controllers need hints about hardware setup, e.g. for DMA. * @irq: Initializes spi_device.irq; depends on how the board is wired. * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits * from the chip datasheet and board-specific signal quality issues. * @bus_num: Identifies which spi_controller parents the spi_device; unused * by spi_new_device(), and otherwise depends on board wiring. * @chip_select: Initializes spi_device.chip_select; depends on how * the board is wired. * @mode: Initializes spi_device.mode; based on the chip datasheet, board * wiring (some devices support both 3WIRE and standard modes), and * possibly presence of an inverter in the chipselect path. * * When adding new SPI devices to the device tree, these structures serve * as a partial device template. They hold information which can't always * be determined by drivers. Information that probe() can establish (such * as the default transfer wordsize) is not included here. * * These structures are used in two places. Their primary role is to * be stored in tables of board-specific device descriptors, which are * declared early in board initialization and then used (much later) to * populate a controller's device tree after the that controller's driver * initializes. A secondary (and atypical) role is as a parameter to * spi_new_device() call, which happens after those controller drivers * are active in some dynamic board configuration models. */ struct spi_board_info { … }; #ifdef CONFIG_SPI extern int spi_register_board_info(struct spi_board_info const *info, unsigned n); #else /* Board init code may ignore whether SPI is configured or not */ static inline int spi_register_board_info(struct spi_board_info const *info, unsigned n) { return 0; } #endif /* * If you're hotplugging an adapter with devices (parport, USB, etc) * use spi_new_device() to describe each device. You can also call * spi_unregister_device() to start making that device vanish, but * normally that would be handled by spi_unregister_controller(). * * You can also use spi_alloc_device() and spi_add_device() to use a two * stage registration sequence for each spi_device. This gives the caller * some more control over the spi_device structure before it is registered, * but requires that caller to initialize fields that would otherwise * be defined using the board info. */ extern struct spi_device * spi_alloc_device(struct spi_controller *ctlr); extern int spi_add_device(struct spi_device *spi); extern struct spi_device * spi_new_device(struct spi_controller *, struct spi_board_info *); extern void spi_unregister_device(struct spi_device *spi); extern const struct spi_device_id * spi_get_device_id(const struct spi_device *sdev); extern const void * spi_get_device_match_data(const struct spi_device *sdev); static inline bool spi_transfer_is_last(struct spi_controller *ctlr, struct spi_transfer *xfer) { … } #endif /* __LINUX_SPI_H */
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