/* 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 16
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 {
struct u64_stats_sync syncp;
u64_stats_t messages;
u64_stats_t transfers;
u64_stats_t errors;
u64_stats_t timedout;
u64_stats_t spi_sync;
u64_stats_t spi_sync_immediate;
u64_stats_t spi_async;
u64_stats_t bytes;
u64_stats_t bytes_rx;
u64_stats_t bytes_tx;
#define SPI_STATISTICS_HISTO_SIZE 17
u64_stats_t transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
u64_stats_t transfers_split_maxsize;
};
#define SPI_STATISTICS_ADD_TO_FIELD(pcpu_stats, field, count) \
do { \
struct spi_statistics *__lstats; \
get_cpu(); \
__lstats = this_cpu_ptr(pcpu_stats); \
u64_stats_update_begin(&__lstats->syncp); \
u64_stats_add(&__lstats->field, count); \
u64_stats_update_end(&__lstats->syncp); \
put_cpu(); \
} while (0)
#define SPI_STATISTICS_INCREMENT_FIELD(pcpu_stats, field) \
do { \
struct spi_statistics *__lstats; \
get_cpu(); \
__lstats = this_cpu_ptr(pcpu_stats); \
u64_stats_update_begin(&__lstats->syncp); \
u64_stats_inc(&__lstats->field); \
u64_stats_update_end(&__lstats->syncp); \
put_cpu(); \
} while (0)
/**
* struct spi_delay - SPI delay information
* @value: Value for the delay
* @unit: Unit for the delay
*/
struct spi_delay {
#define SPI_DELAY_UNIT_USECS 0
#define SPI_DELAY_UNIT_NSECS 1
#define SPI_DELAY_UNIT_SCK 2
u16 value;
u8 unit;
};
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 {
struct device dev;
struct spi_controller *controller;
u32 max_speed_hz;
u8 chip_select[SPI_CS_CNT_MAX];
u8 bits_per_word;
bool rt;
#define SPI_NO_TX BIT(31) /* No transmit wire */
#define SPI_NO_RX BIT(30) /* No receive wire */
/*
* TPM specification defines flow control over SPI. Client device
* can insert a wait state on MISO when address is transmitted by
* controller on MOSI. Detecting the wait state in software is only
* possible for full duplex controllers. For controllers that support
* only half-duplex, the wait state detection needs to be implemented
* in hardware. TPM devices would set this flag when hardware flow
* control is expected from SPI controller.
*/
#define SPI_TPM_HW_FLOW BIT(29) /* TPM HW flow control */
/*
* All bits defined above should be covered by SPI_MODE_KERNEL_MASK.
* The SPI_MODE_KERNEL_MASK has the SPI_MODE_USER_MASK counterpart,
* which is defined in 'include/uapi/linux/spi/spi.h'.
* The bits defined here are from bit 31 downwards, while in
* SPI_MODE_USER_MASK are from 0 upwards.
* These bits must not overlap. A static assert check should make sure of that.
* If adding extra bits, make sure to decrease the bit index below as well.
*/
#define SPI_MODE_KERNEL_MASK (~(BIT(29) - 1))
u32 mode;
int irq;
void *controller_state;
void *controller_data;
char modalias[SPI_NAME_SIZE];
const char *driver_override;
struct gpio_desc *cs_gpiod[SPI_CS_CNT_MAX]; /* Chip select gpio desc */
struct spi_delay word_delay; /* Inter-word delay */
/* CS delays */
struct spi_delay cs_setup;
struct spi_delay cs_hold;
struct spi_delay cs_inactive;
/* The statistics */
struct spi_statistics __percpu *pcpu_statistics;
/* Bit mask of the chipselect(s) that the driver need to use from
* the chipselect array.When the controller is capable to handle
* multiple chip selects & memories are connected in parallel
* then more than one bit need to be set in cs_index_mask.
*/
u32 cs_index_mask : SPI_CS_CNT_MAX;
/*
* Likely need more hooks for more protocol options affecting how
* the controller talks to each chip, like:
* - memory packing (12 bit samples into low bits, others zeroed)
* - priority
* - chipselect delays
* - ...
*/
};
/* Make sure that SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK don't overlap */
static_assert((SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK) == 0,
"SPI_MODE_USER_MASK & SPI_MODE_KERNEL_MASK must not overlap");
static inline struct spi_device *to_spi_device(const struct device *dev)
{
return dev ? container_of(dev, struct spi_device, dev) : NULL;
}
/* Most drivers won't need to care about device refcounting */
static inline struct spi_device *spi_dev_get(struct spi_device *spi)
{
return (spi && get_device(&spi->dev)) ? spi : NULL;
}
static inline void spi_dev_put(struct spi_device *spi)
{
if (spi)
put_device(&spi->dev);
}
/* ctldata is for the bus_controller driver's runtime state */
static inline void *spi_get_ctldata(const struct spi_device *spi)
{
return spi->controller_state;
}
static inline void spi_set_ctldata(struct spi_device *spi, void *state)
{
spi->controller_state = state;
}
/* Device driver data */
static inline void spi_set_drvdata(struct spi_device *spi, void *data)
{
dev_set_drvdata(&spi->dev, data);
}
static inline void *spi_get_drvdata(const struct spi_device *spi)
{
return dev_get_drvdata(&spi->dev);
}
static inline u8 spi_get_chipselect(const struct spi_device *spi, u8 idx)
{
return spi->chip_select[idx];
}
static inline void spi_set_chipselect(struct spi_device *spi, u8 idx, u8 chipselect)
{
spi->chip_select[idx] = chipselect;
}
static inline struct gpio_desc *spi_get_csgpiod(const struct spi_device *spi, u8 idx)
{
return spi->cs_gpiod[idx];
}
static inline void spi_set_csgpiod(struct spi_device *spi, u8 idx, struct gpio_desc *csgpiod)
{
spi->cs_gpiod[idx] = csgpiod;
}
static inline bool spi_is_csgpiod(struct spi_device *spi)
{
u8 idx;
for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
if (spi_get_csgpiod(spi, idx))
return true;
}
return false;
}
/**
* 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 {
const struct spi_device_id *id_table;
int (*probe)(struct spi_device *spi);
void (*remove)(struct spi_device *spi);
void (*shutdown)(struct spi_device *spi);
struct device_driver driver;
};
#define to_spi_driver(__drv) \
( __drv ? container_of_const(__drv, struct spi_driver, driver) : NULL )
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)
{
if (sdrv)
driver_unregister(&sdrv->driver);
}
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) \
__spi_register_driver(THIS_MODULE, 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) \
module_driver(__spi_driver, spi_register_driver, \
spi_unregister_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().
* @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 {
struct device dev;
struct list_head list;
/*
* Other than negative (== assign one dynamically), bus_num is fully
* board-specific. Usually that simplifies to being SoC-specific.
* example: one SoC has three SPI controllers, numbered 0..2,
* and one board's schematics might show it using SPI-2. Software
* would normally use bus_num=2 for that controller.
*/
s16 bus_num;
/*
* Chipselects will be integral to many controllers; some others
* might use board-specific GPIOs.
*/
u16 num_chipselect;
/* Some SPI controllers pose alignment requirements on DMAable
* buffers; let protocol drivers know about these requirements.
*/
u16 dma_alignment;
/* spi_device.mode flags understood by this controller driver */
u32 mode_bits;
/* spi_device.mode flags override flags for this controller */
u32 buswidth_override_bits;
/* Bitmask of supported bits_per_word for transfers */
u32 bits_per_word_mask;
#define SPI_BPW_MASK(bits) BIT((bits) - 1)
#define SPI_BPW_RANGE_MASK(min, max) GENMASK((max) - 1, (min) - 1)
/* Limits on transfer speed */
u32 min_speed_hz;
u32 max_speed_hz;
/* Other constraints relevant to this driver */
u16 flags;
#define SPI_CONTROLLER_HALF_DUPLEX BIT(0) /* Can't do full duplex */
#define SPI_CONTROLLER_NO_RX BIT(1) /* Can't do buffer read */
#define SPI_CONTROLLER_NO_TX BIT(2) /* Can't do buffer write */
#define SPI_CONTROLLER_MUST_RX BIT(3) /* Requires rx */
#define SPI_CONTROLLER_MUST_TX BIT(4) /* Requires tx */
#define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must select slave */
#define SPI_CONTROLLER_SUSPENDED BIT(6) /* Currently suspended */
/*
* The spi-controller has multi chip select capability and can
* assert/de-assert more than one chip select at once.
*/
#define SPI_CONTROLLER_MULTI_CS BIT(7)
/* Flag indicating if the allocation of this struct is devres-managed */
bool devm_allocated;
union {
/* Flag indicating this is an SPI slave controller */
bool slave;
/* Flag indicating this is an SPI target controller */
bool target;
};
/*
* On some hardware transfer / message size may be constrained
* the limit may depend on device transfer settings.
*/
size_t (*max_transfer_size)(struct spi_device *spi);
size_t (*max_message_size)(struct spi_device *spi);
/* I/O mutex */
struct mutex io_mutex;
/* Used to avoid adding the same CS twice */
struct mutex add_lock;
/* Lock and mutex for SPI bus locking */
spinlock_t bus_lock_spinlock;
struct mutex bus_lock_mutex;
/* Flag indicating that the SPI bus is locked for exclusive use */
bool bus_lock_flag;
/*
* Setup mode and clock, etc (SPI driver may call many times).
*
* IMPORTANT: this may be called when transfers to another
* device are active. DO NOT UPDATE SHARED REGISTERS in ways
* which could break those transfers.
*/
int (*setup)(struct spi_device *spi);
/*
* set_cs_timing() method is for SPI controllers that supports
* configuring CS timing.
*
* This hook allows SPI client drivers to request SPI controllers
* to configure specific CS timing through spi_set_cs_timing() after
* spi_setup().
*/
int (*set_cs_timing)(struct spi_device *spi);
/*
* Bidirectional bulk transfers
*
* + The transfer() method may not sleep; its main role is
* just to add the message to the queue.
* + For now there's no remove-from-queue operation, or
* any other request management
* + To a given spi_device, message queueing is pure FIFO
*
* + The controller's main job is to process its message queue,
* selecting a chip (for masters), then transferring data
* + If there are multiple spi_device children, the i/o queue
* arbitration algorithm is unspecified (round robin, FIFO,
* priority, reservations, preemption, etc)
*
* + Chipselect stays active during the entire message
* (unless modified by spi_transfer.cs_change != 0).
* + The message transfers use clock and SPI mode parameters
* previously established by setup() for this device
*/
int (*transfer)(struct spi_device *spi,
struct spi_message *mesg);
/* Called on release() to free memory provided by spi_controller */
void (*cleanup)(struct spi_device *spi);
/*
* Used to enable core support for DMA handling, if can_dma()
* exists and returns true then the transfer will be mapped
* prior to transfer_one() being called. The driver should
* not modify or store xfer and dma_tx and dma_rx must be set
* while the device is prepared.
*/
bool (*can_dma)(struct spi_controller *ctlr,
struct spi_device *spi,
struct spi_transfer *xfer);
struct device *dma_map_dev;
struct device *cur_rx_dma_dev;
struct device *cur_tx_dma_dev;
/*
* These hooks are for drivers that want to use the generic
* controller transfer queueing mechanism. If these are used, the
* transfer() function above must NOT be specified by the driver.
* Over time we expect SPI drivers to be phased over to this API.
*/
bool queued;
struct kthread_worker *kworker;
struct kthread_work pump_messages;
spinlock_t queue_lock;
struct list_head queue;
struct spi_message *cur_msg;
struct completion cur_msg_completion;
bool cur_msg_incomplete;
bool cur_msg_need_completion;
bool busy;
bool running;
bool rt;
bool auto_runtime_pm;
bool fallback;
bool last_cs_mode_high;
s8 last_cs[SPI_CS_CNT_MAX];
u32 last_cs_index_mask : SPI_CS_CNT_MAX;
struct completion xfer_completion;
size_t max_dma_len;
int (*optimize_message)(struct spi_message *msg);
int (*unoptimize_message)(struct spi_message *msg);
int (*prepare_transfer_hardware)(struct spi_controller *ctlr);
int (*transfer_one_message)(struct spi_controller *ctlr,
struct spi_message *mesg);
int (*unprepare_transfer_hardware)(struct spi_controller *ctlr);
int (*prepare_message)(struct spi_controller *ctlr,
struct spi_message *message);
int (*unprepare_message)(struct spi_controller *ctlr,
struct spi_message *message);
int (*target_abort)(struct spi_controller *ctlr);
/*
* These hooks are for drivers that use a generic implementation
* of transfer_one_message() provided by the core.
*/
void (*set_cs)(struct spi_device *spi, bool enable);
int (*transfer_one)(struct spi_controller *ctlr, struct spi_device *spi,
struct spi_transfer *transfer);
void (*handle_err)(struct spi_controller *ctlr,
struct spi_message *message);
/* Optimized handlers for SPI memory-like operations. */
const struct spi_controller_mem_ops *mem_ops;
const struct spi_controller_mem_caps *mem_caps;
/* GPIO chip select */
struct gpio_desc **cs_gpiods;
bool use_gpio_descriptors;
s8 unused_native_cs;
s8 max_native_cs;
/* Statistics */
struct spi_statistics __percpu *pcpu_statistics;
/* DMA channels for use with core dmaengine helpers */
struct dma_chan *dma_tx;
struct dma_chan *dma_rx;
/* Dummy data for full duplex devices */
void *dummy_rx;
void *dummy_tx;
int (*fw_translate_cs)(struct spi_controller *ctlr, unsigned cs);
/*
* Driver sets this field to indicate it is able to snapshot SPI
* transfers (needed e.g. for reading the time of POSIX clocks)
*/
bool ptp_sts_supported;
/* Interrupt enable state during PTP system timestamping */
unsigned long irq_flags;
/* Flag for enabling opportunistic skipping of the queue in spi_sync */
bool queue_empty;
bool must_async;
bool defer_optimize_message;
};
static inline void *spi_controller_get_devdata(struct spi_controller *ctlr)
{
return dev_get_drvdata(&ctlr->dev);
}
static inline void spi_controller_set_devdata(struct spi_controller *ctlr,
void *data)
{
dev_set_drvdata(&ctlr->dev, data);
}
static inline struct spi_controller *spi_controller_get(struct spi_controller *ctlr)
{
if (!ctlr || !get_device(&ctlr->dev))
return NULL;
return ctlr;
}
static inline void spi_controller_put(struct spi_controller *ctlr)
{
if (ctlr)
put_device(&ctlr->dev);
}
static inline bool spi_controller_is_target(struct spi_controller *ctlr)
{
return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->target;
}
/* 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)
{
return __spi_alloc_controller(host, size, false);
}
static inline struct spi_controller *spi_alloc_slave(struct device *host,
unsigned int size)
{
if (!IS_ENABLED(CONFIG_SPI_SLAVE))
return NULL;
return __spi_alloc_controller(host, size, true);
}
static inline struct spi_controller *spi_alloc_host(struct device *dev,
unsigned int size)
{
return __spi_alloc_controller(dev, size, false);
}
static inline struct spi_controller *spi_alloc_target(struct device *dev,
unsigned int size)
{
if (!IS_ENABLED(CONFIG_SPI_SLAVE))
return NULL;
return __spi_alloc_controller(dev, size, true);
}
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)
{
return __devm_spi_alloc_controller(dev, size, false);
}
static inline struct spi_controller *devm_spi_alloc_slave(struct device *dev,
unsigned int size)
{
if (!IS_ENABLED(CONFIG_SPI_SLAVE))
return NULL;
return __devm_spi_alloc_controller(dev, size, true);
}
static inline struct spi_controller *devm_spi_alloc_host(struct device *dev,
unsigned int size)
{
return __devm_spi_alloc_controller(dev, size, false);
}
static inline struct spi_controller *devm_spi_alloc_target(struct device *dev,
unsigned int size)
{
if (!IS_ENABLED(CONFIG_SPI_SLAVE))
return NULL;
return __devm_spi_alloc_controller(dev, size, true);
}
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) && IS_ENABLED(CONFIG_SPI_MASTER)
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);
#else
static inline struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
{
return NULL;
}
static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
struct acpi_device *adev,
int index)
{
return ERR_PTR(-ENODEV);
}
static inline int acpi_spi_count_resources(struct acpi_device *adev)
{
return 0;
}
#endif
/*
* SPI resource management while processing a SPI message
*/
typedef void (*spi_res_release_t)(struct spi_controller *ctlr,
struct spi_message *msg,
void *res);
/**
* 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 {
struct list_head entry;
spi_res_release_t release;
unsigned long long data[]; /* Guarantee ull alignment */
};
/*---------------------------------------------------------------------------*/
/*
* 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 {
/*
* It's okay if tx_buf == rx_buf (right?).
* For MicroWire, one buffer must be NULL.
* Buffers must work with dma_*map_single() calls.
*/
const void *tx_buf;
void *rx_buf;
unsigned len;
#define SPI_TRANS_FAIL_NO_START BIT(0)
#define SPI_TRANS_FAIL_IO BIT(1)
u16 error;
bool tx_sg_mapped;
bool rx_sg_mapped;
struct sg_table tx_sg;
struct sg_table rx_sg;
dma_addr_t tx_dma;
dma_addr_t rx_dma;
unsigned dummy_data:1;
unsigned cs_off:1;
unsigned cs_change:1;
unsigned tx_nbits:4;
unsigned rx_nbits:4;
unsigned timestamped:1;
#define SPI_NBITS_SINGLE 0x01 /* 1-bit transfer */
#define SPI_NBITS_DUAL 0x02 /* 2-bit transfer */
#define SPI_NBITS_QUAD 0x04 /* 4-bit transfer */
#define SPI_NBITS_OCTAL 0x08 /* 8-bit transfer */
u8 bits_per_word;
struct spi_delay delay;
struct spi_delay cs_change_delay;
struct spi_delay word_delay;
u32 speed_hz;
u32 effective_speed_hz;
unsigned int ptp_sts_word_pre;
unsigned int ptp_sts_word_post;
struct ptp_system_timestamp *ptp_sts;
struct list_head transfer_list;
};
/**
* 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 {
struct list_head transfers;
struct spi_device *spi;
/* spi_optimize_message() was called for this message */
bool pre_optimized;
/* __spi_optimize_message() was called for this message */
bool optimized;
/* spi_prepare_message() was called for this message */
bool prepared;
/*
* REVISIT: we might want a flag affecting the behavior of the
* last transfer ... allowing things like "read 16 bit length L"
* immediately followed by "read L bytes". Basically imposing
* a specific message scheduling algorithm.
*
* Some controller drivers (message-at-a-time queue processing)
* could provide that as their default scheduling algorithm. But
* others (with multi-message pipelines) could need a flag to
* tell them about such special cases.
*/
/* Completion is reported through a callback */
int status;
void (*complete)(void *context);
void *context;
unsigned frame_length;
unsigned actual_length;
/*
* For optional use by whatever driver currently owns the
* spi_message ... between calls to spi_async and then later
* complete(), that's the spi_controller controller driver.
*/
struct list_head queue;
void *state;
/*
* Optional state for use by controller driver between calls to
* __spi_optimize_message() and __spi_unoptimize_message().
*/
void *opt_state;
/* List of spi_res resources when the SPI message is processed */
struct list_head resources;
};
static inline void spi_message_init_no_memset(struct spi_message *m)
{
INIT_LIST_HEAD(&m->transfers);
INIT_LIST_HEAD(&m->resources);
}
static inline void spi_message_init(struct spi_message *m)
{
memset(m, 0, sizeof *m);
spi_message_init_no_memset(m);
}
static inline void
spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
{
list_add_tail(&t->transfer_list, &m->transfers);
}
static inline void
spi_transfer_del(struct spi_transfer *t)
{
list_del(&t->transfer_list);
}
static inline int
spi_transfer_delay_exec(struct spi_transfer *t)
{
return spi_delay_exec(&t->delay, 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)
{
unsigned int i;
spi_message_init(m);
for (i = 0; i < num_xfers; ++i)
spi_message_add_tail(&xfers[i], m);
}
/*
* 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)
{
struct spi_message_with_transfers {
struct spi_message m;
struct spi_transfer t[];
} *mwt;
unsigned i;
mwt = kzalloc(struct_size(mwt, t, ntrans), flags);
if (!mwt)
return NULL;
spi_message_init_no_memset(&mwt->m);
for (i = 0; i < ntrans; i++)
spi_message_add_tail(&mwt->t[i], &mwt->m);
return &mwt->m;
}
static inline void spi_message_free(struct spi_message *m)
{
kfree(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_target_abort(struct spi_device *spi);
static inline size_t
spi_max_message_size(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
if (!ctlr->max_message_size)
return SIZE_MAX;
return ctlr->max_message_size(spi);
}
static inline size_t
spi_max_transfer_size(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
size_t tr_max = SIZE_MAX;
size_t msg_max = spi_max_message_size(spi);
if (ctlr->max_transfer_size)
tr_max = ctlr->max_transfer_size(spi);
/* Transfer size limit must not be greater than message size limit */
return min(tr_max, msg_max);
}
/**
* 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)
{
u32 bpw_mask = spi->controller->bits_per_word_mask;
if (bpw == 8 || (bpw <= 32 && bpw_mask & SPI_BPW_MASK(bpw)))
return true;
return false;
}
/**
* 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)
{
return max(xfer->len * 8 * 2 / (xfer->speed_hz / 1000), 500U);
}
/*---------------------------------------------------------------------------*/
/* SPI transfer replacement methods which make use of spi_res */
struct spi_replaced_transfers;
typedef void (*spi_replaced_release_t)(struct spi_controller *ctlr,
struct spi_message *msg,
struct spi_replaced_transfers *res);
/**
* 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_replaced_release_t release;
void *extradata;
struct list_head replaced_transfers;
struct list_head *replaced_after;
size_t inserted;
struct spi_transfer inserted_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)
{
struct spi_message msg;
spi_message_init_with_transfers(&msg, xfers, num_xfers);
return spi_sync(spi, &msg);
}
/**
* 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)
{
struct spi_transfer t = {
.tx_buf = buf,
.len = len,
};
return spi_sync_transfer(spi, &t, 1);
}
/**
* 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)
{
struct spi_transfer t = {
.rx_buf = buf,
.len = len,
};
return spi_sync_transfer(spi, &t, 1);
}
/* 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)
{
ssize_t status;
u8 result;
status = spi_write_then_read(spi, &cmd, 1, &result, 1);
/* Return negative errno or unsigned value */
return (status < 0) ? status : result;
}
/**
* 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)
{
ssize_t status;
u16 result;
status = spi_write_then_read(spi, &cmd, 1, &result, 2);
/* Return negative errno or unsigned value */
return (status < 0) ? status : result;
}
/**
* 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)
{
ssize_t status;
__be16 result;
status = spi_write_then_read(spi, &cmd, 1, &result, 2);
if (status < 0)
return status;
return be16_to_cpu(result);
}
/*---------------------------------------------------------------------------*/
/*
* 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 {
/*
* The device name and module name are coupled, like platform_bus;
* "modalias" is normally the driver name.
*
* platform_data goes to spi_device.dev.platform_data,
* controller_data goes to spi_device.controller_data,
* IRQ is copied too.
*/
char modalias[SPI_NAME_SIZE];
const void *platform_data;
const struct software_node *swnode;
void *controller_data;
int irq;
/* Slower signaling on noisy or low voltage boards */
u32 max_speed_hz;
/*
* bus_num is board specific and matches the bus_num of some
* spi_controller that will probably be registered later.
*
* chip_select reflects how this chip is wired to that master;
* it's less than num_chipselect.
*/
u16 bus_num;
u16 chip_select;
/*
* mode becomes spi_device.mode, and is essential for chips
* where the default of SPI_CS_HIGH = 0 is wrong.
*/
u32 mode;
/*
* ... may need additional spi_device chip config data here.
* avoid stuff protocol drivers can set; but include stuff
* needed to behave without being bound to a driver:
* - quirks like clock rate mattering when not selected
*/
};
#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)
{
return list_is_last(&xfer->transfer_list, &ctlr->cur_msg->transfers);
}
#endif /* __LINUX_SPI_H */
Codebase Browser
linux