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Diffstat (limited to 'ANDROID_3.4.5/include/linux/spi/spi.h')
| -rw-r--r-- | ANDROID_3.4.5/include/linux/spi/spi.h | 859 |
1 files changed, 0 insertions, 859 deletions
diff --git a/ANDROID_3.4.5/include/linux/spi/spi.h b/ANDROID_3.4.5/include/linux/spi/spi.h deleted file mode 100644 index fa702aeb..00000000 --- a/ANDROID_3.4.5/include/linux/spi/spi.h +++ /dev/null @@ -1,859 +0,0 @@ -/* - * Copyright (C) 2005 David Brownell - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ - -#ifndef __LINUX_SPI_H -#define __LINUX_SPI_H - -#include <linux/device.h> -#include <linux/mod_devicetable.h> -#include <linux/slab.h> -#include <linux/kthread.h> - -/* - * INTERFACES between SPI master-side drivers and SPI infrastructure. - * (There's no SPI slave support for Linux yet...) - */ -extern struct bus_type spi_bus_type; - -/** - * struct spi_device - Master side proxy for an SPI slave device - * @dev: Driver model representation of the device. - * @master: 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: Chipselect, distinguishing chips handled by @master. - * @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. - * @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 - * - * 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_master *master; - u32 max_speed_hz; - u8 chip_select; - u8 mode; -#define SPI_CPHA 0x01 /* clock phase */ -#define SPI_CPOL 0x02 /* clock polarity */ -#define SPI_MODE_0 (0|0) /* (original MicroWire) */ -#define SPI_MODE_1 (0|SPI_CPHA) -#define SPI_MODE_2 (SPI_CPOL|0) -#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) -#define SPI_CS_HIGH 0x04 /* chipselect active high? */ -#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ -#define SPI_3WIRE 0x10 /* SI/SO signals shared */ -#define SPI_LOOP 0x20 /* loopback mode */ -#define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */ -#define SPI_READY 0x80 /* slave pulls low to pause */ - u8 bits_per_word; - int irq; - void *controller_state; - void *controller_data; - char modalias[SPI_NAME_SIZE]; - - /* - * 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 - * - drop chipselect after each word - * - chipselect delays - * - ... - */ -}; - -static inline struct spi_device *to_spi_device(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_master driver's runtime state */ -static inline void *spi_get_ctldata(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(struct spi_device *spi) -{ - return dev_get_drvdata(&spi->dev); -} - -struct spi_message; - - - -/** - * 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 - * @suspend: Standard suspend callback used during system state transitions - * @resume: Standard resume callback used during system state transitions - * @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); - int (*remove)(struct spi_device *spi); - void (*shutdown)(struct spi_device *spi); - int (*suspend)(struct spi_device *spi, pm_message_t mesg); - int (*resume)(struct spi_device *spi); - struct device_driver driver; -}; - -static inline struct spi_driver *to_spi_driver(struct device_driver *drv) -{ - return drv ? container_of(drv, struct spi_driver, driver) : NULL; -} - -extern int spi_register_driver(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); -} - -/** - * 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_master - interface to SPI master controller - * @dev: device interface to this driver - * @list: link with the global spi_master 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 - * @flags: other constraints relevant to this driver - * @bus_lock_spinlock: spinlock for SPI bus locking - * @bus_lock_mutex: mutex for SPI bus locking - * @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. - * @transfer: adds a message to the controller's transfer queue. - * @cleanup: frees controller-specific state - * @queued: whether this master is providing an internal message queue - * @kworker: thread struct for message pump - * @kworker_task: pointer to task for message pump kworker thread - * @pump_messages: work struct for scheduling work to the message pump - * @queue_lock: spinlock to syncronise access to message queue - * @queue: message queue - * @cur_msg: the currently in-flight message - * @busy: message pump is busy - * @running: message pump is running - * @rt: whether this queue is set to run as a realtime task - * @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 - * transfer - * @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 - * - * Each SPI master 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_master { - 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 */ - u16 mode_bits; - - /* other constraints relevant to this driver */ - u16 flags; -#define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ -#define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ -#define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ - - /* 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); - - /* 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 master's main job is to process its message queue, - * selecting a chip 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_master */ - void (*cleanup)(struct spi_device *spi); - - /* - * These hooks are for drivers that want to use the generic - * master 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 task_struct *kworker_task; - struct kthread_work pump_messages; - spinlock_t queue_lock; - struct list_head queue; - struct spi_message *cur_msg; - bool busy; - bool running; - bool rt; - - int (*prepare_transfer_hardware)(struct spi_master *master); - int (*transfer_one_message)(struct spi_master *master, - struct spi_message *mesg); - int (*unprepare_transfer_hardware)(struct spi_master *master); -}; - -static inline void *spi_master_get_devdata(struct spi_master *master) -{ - return dev_get_drvdata(&master->dev); -} - -static inline void spi_master_set_devdata(struct spi_master *master, void *data) -{ - dev_set_drvdata(&master->dev, data); -} - -static inline struct spi_master *spi_master_get(struct spi_master *master) -{ - if (!master || !get_device(&master->dev)) - return NULL; - return master; -} - -static inline void spi_master_put(struct spi_master *master) -{ - if (master) - put_device(&master->dev); -} - -/* PM calls that need to be issued by the driver */ -extern int spi_master_suspend(struct spi_master *master); -extern int spi_master_resume(struct spi_master *master); - -/* Calls the driver make to interact with the message queue */ -extern struct spi_message *spi_get_next_queued_message(struct spi_master *master); -extern void spi_finalize_current_message(struct spi_master *master); - -/* the spi driver core manages memory for the spi_master classdev */ -extern struct spi_master * -spi_alloc_master(struct device *host, unsigned size); - -extern int spi_register_master(struct spi_master *master); -extern void spi_unregister_master(struct spi_master *master); - -extern struct spi_master *spi_busnum_to_master(u16 busnum); - -/*---------------------------------------------------------------------------*/ - -/* - * 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, if @spi_message.is_dma_mapped - * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped - * @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. - * @cs_change: affects chipselect after this transfer completes - * @delay_usecs: microseconds to delay after this transfer before - * (optionally) changing the chipselect status, then starting - * the next transfer or completing this @spi_message. - * @transfer_list: transfers are sequenced through @spi_message.transfers - * - * 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 intactive. - * - * 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 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 - */ - const void *tx_buf; - void *rx_buf; - unsigned len; - - dma_addr_t tx_dma; - dma_addr_t rx_dma; - - unsigned cs_change:1; - u8 bits_per_word; - u16 delay_usecs; - u32 speed_hz; - - 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 - * @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 - * @actual_length: the total number of bytes that were transferred in all - * successful segments - * @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 - * - * 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 - * as 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 alway 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; - - unsigned is_dma_mapped:1; - - /* 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 */ - void (*complete)(void *context); - void *context; - unsigned actual_length; - int status; - - /* for optional use by whatever driver currently owns the - * spi_message ... between calls to spi_async and then later - * complete(), that's the spi_master controller driver. - */ - struct list_head queue; - void *state; -}; - -static inline void spi_message_init(struct spi_message *m) -{ - memset(m, 0, sizeof *m); - INIT_LIST_HEAD(&m->transfers); -} - -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); -} - -/* 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); - if (m) { - unsigned i; - struct spi_transfer *t = (struct spi_transfer *)(m + 1); - - INIT_LIST_HEAD(&m->transfers); - for (i = 0; i < ntrans; i++, t++) - spi_message_add_tail(t, m); - } - return m; -} - -static inline void spi_message_free(struct spi_message *m) -{ - kfree(m); -} - -extern int spi_setup(struct spi_device *spi); -extern int spi_async(struct spi_device *spi, struct spi_message *message); -extern int spi_async_locked(struct spi_device *spi, - struct spi_message *message); - -/*---------------------------------------------------------------------------*/ - -/* 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_master *master); -extern int spi_bus_unlock(struct spi_master *master); - -/** - * spi_write - SPI synchronous write - * @spi: device to which data will be written - * @buf: data buffer - * @len: data buffer size - * Context: can sleep - * - * This writes the buffer and returns zero or a negative error code. - * Callable only from contexts that can sleep. - */ -static inline int -spi_write(struct spi_device *spi, const void *buf, size_t len) -{ - struct spi_transfer t = { - .tx_buf = buf, - .len = len, - }; - struct spi_message m; - - spi_message_init(&m); - spi_message_add_tail(&t, &m); - return spi_sync(spi, &m); -} - -/** - * spi_read - SPI synchronous read - * @spi: device from which data will be read - * @buf: data buffer - * @len: data buffer size - * Context: can sleep - * - * This reads the buffer and returns zero or a negative error code. - * Callable only from contexts that can sleep. - */ -static inline int -spi_read(struct spi_device *spi, void *buf, size_t len) -{ - struct spi_transfer t = { - .rx_buf = buf, - .len = len, - }; - struct spi_message m; - - spi_message_init(&m); - spi_message_add_tail(&t, &m); - return spi_sync(spi, &m); -} - -/* 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 - * - * This returns the (unsigned) eight bit number returned by the - * device, or else a negative error code. Callable only from - * contexts that can sleep. - */ -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 - * - * This returns the (unsigned) sixteen bit number returned by the - * device, or else a negative error code. Callable only from - * contexts that can sleep. - * - * The number is returned in wire-order, which is at least sometimes - * big-endian. - */ -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, (u8 *) &result, 2); - - /* return negative errno or unsigned value */ - return (status < 0) ? status : 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 nonstatic 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. - * @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_master 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; - 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_master 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. - */ - u8 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_master(). - * - * 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_master *master); - -extern int -spi_add_device(struct spi_device *spi); - -extern struct spi_device * -spi_new_device(struct spi_master *, struct spi_board_info *); - -static inline void -spi_unregister_device(struct spi_device *spi) -{ - if (spi) - device_unregister(&spi->dev); -} - -extern const struct spi_device_id * -spi_get_device_id(const struct spi_device *sdev); - -#endif /* __LINUX_SPI_H */ |