diff options
Diffstat (limited to 'include/linux/spi/spi.h')
| -rw-r--r-- | include/linux/spi/spi.h | 171 |
1 files changed, 91 insertions, 80 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 32c94eae8926..7f8b478fdeb3 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -6,18 +6,19 @@ #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/mod_devicetable.h> -#include <linux/slab.h> +#include <linux/gpio/consumer.h> #include <linux/kthread.h> -#include <linux/completion.h> +#include <linux/mod_devicetable.h> +#include <linux/overflow.h> #include <linux/scatterlist.h> -#include <linux/gpio/consumer.h> +#include <linux/slab.h> +#include <linux/u64_stats_sync.h> #include <uapi/linux/spi/spi.h> -#include <linux/acpi.h> -#include <linux/u64_stats_sync.h> struct dma_chan; struct software_node; @@ -36,7 +37,7 @@ extern struct bus_type spi_bus_type; /** * struct spi_statistics - statistics for spi transfers - * @syncp: seqcount to protect members in this struct for per-cpu udate + * @syncp: seqcount to protect members in this struct for per-cpu update * on 32-bit systems * * @messages: number of spi-messages handled @@ -55,7 +56,7 @@ extern struct bus_type spi_bus_type; * @bytes_rx: number of bytes received from device * * @transfer_bytes_histo: - * transfer bytes histogramm + * transfer bytes histogram * * @transfers_split_maxsize: * number of transfers that have been split because of @@ -156,7 +157,7 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg, * 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: gpio descriptor of the chipselect line (optional, NULL when + * @cs_gpiod: GPIO descriptor of the chipselect line (optional, NULL when * not using a GPIO line) * @word_delay: delay to be inserted between consecutive * words of a transfer @@ -212,7 +213,7 @@ struct spi_device { void *controller_data; char modalias[SPI_NAME_SIZE]; const char *driver_override; - struct gpio_desc *cs_gpiod; /* Chip select gpio desc */ + struct gpio_desc *cs_gpiod; /* Chip select GPIO descriptor */ struct spi_delay word_delay; /* Inter-word delay */ /* CS delays */ struct spi_delay cs_setup; @@ -223,7 +224,7 @@ struct spi_device { struct spi_statistics __percpu *pcpu_statistics; /* - * likely need more hooks for more protocol options affecting how + * 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 @@ -299,11 +300,11 @@ static inline void spi_set_csgpiod(struct spi_device *spi, u8 idx, struct gpio_d /** * 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 + * @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 + * @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 @@ -415,7 +416,7 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * @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 syncronise access to message queue + * @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 @@ -473,7 +474,7 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * @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 descs to use as chip select lines; one per CS + * @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 @@ -500,7 +501,7 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * 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 - * @fallback: fallback to pio if dma transfer return failure with + * @fallback: fallback to PIO if DMA transfer return failure with * SPI_TRANS_FAIL_NO_START. * @queue_empty: signal green light for opportunistically skipping the queue * for spi_sync transfers. @@ -522,15 +523,17 @@ struct spi_controller { 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 + /* + * 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 + /* + * Chipselects will be integral to many controllers; some others * might use board-specific GPIOs. */ u16 num_chipselect; @@ -562,8 +565,7 @@ struct spi_controller { #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_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */ +#define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must select slave */ /* Flag indicating if the allocation of this struct is devres-managed */ bool devm_allocated; @@ -576,8 +578,8 @@ struct spi_controller { }; /* - * on some hardware transfer / message size may be constrained - * the limit may depend on device transfer settings + * 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); @@ -595,7 +597,8 @@ struct spi_controller { /* 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). + /* + * 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 @@ -613,18 +616,19 @@ struct spi_controller { */ int (*set_cs_timing)(struct spi_device *spi); - /* Bidirectional bulk transfers + /* + * 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 + * + 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, + * arbitration algorithm is unspecified (round robin, FIFO, * priority, reservations, preemption, etc) * * + Chipselect stays active during the entire message @@ -705,7 +709,7 @@ struct spi_controller { const struct spi_controller_mem_ops *mem_ops; const struct spi_controller_mem_caps *mem_caps; - /* gpio chip select */ + /* GPIO chip select */ struct gpio_desc **cs_gpiods; bool use_gpio_descriptors; s8 unused_native_cs; @@ -789,7 +793,7 @@ 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 */ +/* 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); @@ -878,13 +882,13 @@ typedef void (*spi_res_release_t)(struct spi_controller *ctlr, void *res); /** - * struct spi_res - spi resource management structure + * 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 + * This is based on ideas from devres, but focused on life-cycle + * management during spi_message processing. */ struct spi_res { struct list_head entry; @@ -902,7 +906,7 @@ struct spi_res { * * 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 + * 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.) * @@ -913,8 +917,8 @@ struct spi_res { /** * 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_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, if @spi_message.is_dma_mapped * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped * @tx_nbits: number of bits used for writing. If 0 the default @@ -937,7 +941,7 @@ struct spi_res { * @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 + * 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: Scatterlist for transmit, currently not for client use @@ -966,16 +970,16 @@ struct spi_res { * 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. + * @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. + * 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 + * 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; @@ -1009,7 +1013,7 @@ struct spi_res { * 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 intactive. + * 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 @@ -1023,10 +1027,11 @@ struct spi_res { * and its transfers, ignore them until its completion callback. */ struct spi_transfer { - /* It's ok if tx_buf == rx_buf (right?) - * for MicroWire, one buffer must be null - * buffers must work with dma_*map_single() calls, unless - * spi_message.is_dma_mapped reports a pre-existing mapping + /* + * It's okay if tx_buf == rx_buf (right?). + * For MicroWire, one buffer must be NULL. + * Buffers must work with dma_*map_single() calls, unless + * spi_message.is_dma_mapped reports a pre-existing mapping. */ const void *tx_buf; void *rx_buf; @@ -1046,9 +1051,9 @@ struct spi_transfer { unsigned tx_nbits:3; unsigned rx_nbits:3; unsigned timestamped:1; -#define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */ -#define SPI_NBITS_DUAL 0x02 /* 2bits transfer */ -#define SPI_NBITS_QUAD 0x04 /* 4bits transfer */ +#define SPI_NBITS_SINGLE 0x01 /* 1-bit transfer */ +#define SPI_NBITS_DUAL 0x02 /* 2-bit transfer */ +#define SPI_NBITS_QUAD 0x04 /* 4-bit transfer */ u8 bits_per_word; struct spi_delay delay; struct spi_delay cs_change_delay; @@ -1069,7 +1074,7 @@ 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 - * @is_dma_mapped: if true, the caller provided both dma and cpu virtual + * @is_dma_mapped: if true, the caller provided both DMA and CPU virtual * addresses for each transfer buffer * @complete: called to report transaction completions * @context: the argument to complete() when it's called @@ -1079,8 +1084,10 @@ struct spi_transfer { * @status: zero for success, else negative errno * @queue: for use by whichever driver currently owns the message * @state: for use by whichever driver currently owns the message - * @resources: for resource management when the spi message is processed + * @resources: for resource management when the SPI message is processed * @prepared: spi_prepare_message was called for the this message + * @t: for use with spi_message_alloc() when message and transfers have + * been allocated together * * A @spi_message is used to execute an atomic sequence of data transfers, * each represented by a struct spi_transfer. The sequence is "atomic" @@ -1106,7 +1113,8 @@ struct spi_message { /* spi_prepare_message() was called for this message */ bool prepared; - /* REVISIT: we might want a flag affecting the behavior of the + /* + * 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. @@ -1124,15 +1132,19 @@ struct spi_message { unsigned frame_length; unsigned actual_length; - /* For optional use by whatever driver currently owns the + /* + * 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; - /* List of spi_res reources when the spi message is processed */ + /* List of spi_res resources when the SPI message is processed */ struct list_head resources; + + /* For embedding transfers into the memory of the message */ + struct spi_transfer t[]; }; static inline void spi_message_init_no_memset(struct spi_message *m) @@ -1168,7 +1180,7 @@ 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 + * @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 @@ -1185,24 +1197,21 @@ struct spi_transfer *xfers, unsigned int num_xfers) spi_message_add_tail(&xfers[i], m); } -/* It's fine to embed message and transaction structures in other data +/* + * 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 *m; - m = kzalloc(sizeof(struct spi_message) - + ntrans * sizeof(struct spi_transfer), - flags); + m = kzalloc(struct_size(m, t, ntrans), flags); if (m) { unsigned i; - struct spi_transfer *t = (struct spi_transfer *)(m + 1); spi_message_init_no_memset(m); - for (i = 0; i < ntrans; i++, t++) - spi_message_add_tail(t, m); + for (i = 0; i < ntrans; i++) + spi_message_add_tail(&m->t[i], m); } return m; } @@ -1291,7 +1300,7 @@ typedef void (*spi_replaced_release_t)(struct spi_controller *ctlr, * replacements that have occurred * so that they can get reverted * @release: some extra release code to get executed prior to - * relasing this structure + * 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 @@ -1301,9 +1310,9 @@ typedef void (*spi_replaced_release_t)(struct spi_controller *ctlr, * @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] + * 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 + * as for spi_transfers. */ struct spi_replaced_transfers { spi_replaced_release_t release; @@ -1329,7 +1338,8 @@ extern int spi_split_transfers_maxwords(struct spi_controller *ctlr, /*---------------------------------------------------------------------------*/ -/* All these synchronous SPI transfer routines are utilities layered +/* + * 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. */ @@ -1472,7 +1482,7 @@ static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd) * * Callable only from contexts that can sleep. * - * Return: the (unsigned) sixteen bit number returned by the device in cpu + * 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) @@ -1500,7 +1510,7 @@ static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd) * 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 nonstatic configurations too; enough to handle adding + * support for non-static configurations too; enough to handle adding * parport adapters, or microcontrollers acting as USB-to-SPI bridges. */ @@ -1537,12 +1547,13 @@ static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd) * are active in some dynamic board configuration models. */ struct spi_board_info { - /* The device name and module name are coupled, like platform_bus; + /* + * 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 + * IRQ is copied too. */ char modalias[SPI_NAME_SIZE]; const void *platform_data; @@ -1554,7 +1565,8 @@ struct spi_board_info { u32 max_speed_hz; - /* bus_num is board specific and matches the bus_num of some + /* + * 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; @@ -1563,12 +1575,14 @@ struct spi_board_info { u16 bus_num; u16 chip_select; - /* mode becomes spi_device.mode, and is essential for chips + /* + * 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. + /* + * ... 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 @@ -1585,7 +1599,8 @@ 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) +/* + * 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(). @@ -1623,10 +1638,6 @@ spi_transfer_is_last(struct spi_controller *ctlr, struct spi_transfer *xfer) #define spi_master spi_controller #define SPI_MASTER_HALF_DUPLEX SPI_CONTROLLER_HALF_DUPLEX -#define SPI_MASTER_NO_RX SPI_CONTROLLER_NO_RX -#define SPI_MASTER_NO_TX SPI_CONTROLLER_NO_TX -#define SPI_MASTER_MUST_RX SPI_CONTROLLER_MUST_RX -#define SPI_MASTER_MUST_TX SPI_CONTROLLER_MUST_TX #define spi_master_get_devdata(_ctlr) spi_controller_get_devdata(_ctlr) #define spi_master_set_devdata(_ctlr, _data) \ |