Release 4.12 include/linux/spi/spi.h
/*
* 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.
*/
#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>
#include <linux/completion.h>
#include <linux/scatterlist.h>
struct dma_chan;
struct property_entry;
struct spi_master;
struct spi_transfer;
struct spi_flash_read_message;
/*
* 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_statistics - statistics for spi transfers
* @lock: lock protecting this structure
*
* @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 histogramm
*
* @transfers_split_maxsize:
* number of transfers that have been split because of
* maxsize limit
*/
struct spi_statistics {
spinlock_t lock; /* lock for the whole structure */
unsigned long messages;
unsigned long transfers;
unsigned long errors;
unsigned long timedout;
unsigned long spi_sync;
unsigned long spi_sync_immediate;
unsigned long spi_async;
unsigned long long bytes;
unsigned long long bytes_rx;
unsigned long long bytes_tx;
#define SPI_STATISTICS_HISTO_SIZE 17
unsigned long transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
unsigned long transfers_split_maxsize;
};
void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
struct spi_transfer *xfer,
struct spi_master *master);
#define SPI_STATISTICS_ADD_TO_FIELD(stats, field, count) \
do { \
unsigned long flags; \
spin_lock_irqsave(&(stats)->lock, flags); \
(stats)->field += count; \
spin_unlock_irqrestore(&(stats)->lock, flags); \
} while (0)
#define SPI_STATISTICS_INCREMENT_FIELD(stats, field) \
SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
/**
* 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
* @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
* when not using a GPIO line)
*
* @statistics: statistics for the spi_device
*
* 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 bits_per_word;
u16 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 */
#define SPI_TX_DUAL 0x100 /* transmit with 2 wires */
#define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
#define SPI_RX_DUAL 0x400 /* receive with 2 wires */
#define SPI_RX_QUAD 0x800 /* receive with 4 wires */
int irq;
void *controller_state;
void *controller_data;
char modalias[SPI_NAME_SIZE];
int cs_gpio; /* chip select gpio */
/* the statistics */
struct spi_statistics statistics;
/*
* 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;
}
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/* 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;
}
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static inline void spi_dev_put(struct spi_device *spi)
{
if (spi)
put_device(&spi->dev);
}
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/* ctldata is for the bus_master driver's runtime state */
static inline void *spi_get_ctldata(struct spi_device *spi)
{
return spi->controller_state;
}
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static inline void spi_set_ctldata(struct spi_device *spi, void *state)
{
spi->controller_state = state;
}
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/* device driver data */
static inline void spi_set_drvdata(struct spi_device *spi, void *data)
{
dev_set_drvdata(&spi->dev, data);
}
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static inline void *spi_get_drvdata(struct spi_device *spi)
{
return dev_get_drvdata(&spi->dev);
}
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struct spi_message;
struct spi_transfer;
/**
* 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);
int (*remove)(struct spi_device *spi);
void (*shutdown)(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;
}
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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);
}
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/* 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_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
* @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
* @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
* @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.
* @transfer: adds a message to the controller's transfer queue.
* @cleanup: frees controller-specific state
* @can_dma: determine whether this master supports DMA
* @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
* @idling: the device is entering idle state
* @cur_msg: the currently in-flight message
* @cur_msg_prepared: spi_prepare_message was called for the currently
* in-flight message
* @cur_msg_mapped: message has been mapped for DMA
* @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.
* @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. 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().
* @unprepare_message: undo any work done by prepare_message().
* @spi_flash_read: to support spi-controller hardwares that provide
* accelerated interface to read from flash devices.
* @spi_flash_can_dma: analogous to can_dma() interface, but for
* controllers implementing spi_flash_read.
* @flash_read_supported: spi device supports flash read
* @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
* number. Any individual value may be -ENOENT for CS lines that
* are not GPIOs (driven by the SPI controller itself).
* @statistics: statistics for the spi_master
* @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.
*
* 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;
/* bitmask of supported bits_per_word for transfers */
u32 bits_per_word_mask;
#define SPI_BPW_MASK(bits) BIT((bits) - 1)
#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0U : (BIT(bits) - 1))
#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
/* limits on transfer speed */
u32 min_speed_hz;
u32 max_speed_hz;
/* 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 */
#define SPI_MASTER_MUST_RX BIT(3) /* requires rx */
#define SPI_MASTER_MUST_TX BIT(4) /* requires tx */
#define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */
/*
* 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;
/* 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);
/*
* 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_master *master,
struct spi_device *spi,
struct spi_transfer *xfer);
/*
* 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 idling;
bool busy;
bool running;
bool rt;
bool auto_runtime_pm;
bool cur_msg_prepared;
bool cur_msg_mapped;
struct completion xfer_completion;
size_t max_dma_len;
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);
int (*prepare_message)(struct spi_master *master,
struct spi_message *message);
int (*unprepare_message)(struct spi_master *master,
struct spi_message *message);
int (*spi_flash_read)(struct spi_device *spi,
struct spi_flash_read_message *msg);
bool (*spi_flash_can_dma)(struct spi_device *spi,
struct spi_flash_read_message *msg);
bool (*flash_read_supported)(struct spi_device *spi);
/*
* These hooks are for drivers that use a generic implementation
* of transfer_one_message() provied by the core.
*/
void (*set_cs)(struct spi_device *spi, bool enable);
int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
struct spi_transfer *transfer);
void (*handle_err)(struct spi_master *master,
struct spi_message *message);
/* gpio chip select */
int *cs_gpios;
/* statistics */
struct spi_statistics 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_master *master, unsigned cs);
};
static inline void *spi_master_get_devdata(struct spi_master *master)
{
return dev_get_drvdata(&master->dev);
}
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static inline void spi_master_set_devdata(struct spi_master *master, void *data)
{
dev_set_drvdata(&master->dev, data);
}
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static inline struct spi_master *spi_master_get(struct spi_master *master)
{
if (!master || !get_device(&master->dev))
return NULL;
return master;
}
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static inline void spi_master_put(struct spi_master *master)
{
if (master)
put_device(&master->dev);
}
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/* 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);
extern void spi_finalize_current_transfer(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 int devm_spi_register_master(struct device *dev,
struct spi_master *master);
extern void spi_unregister_master(struct spi_master *master);
extern struct spi_master *spi_busnum_to_master(u16 busnum);
/*
* SPI resource management while processing a SPI message
*/
typedef void (*spi_res_release_t)(struct spi_master *master,
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 */
};
extern void *spi_res_alloc(struct spi_device *spi,
spi_res_release_t release,
size_t size, gfp_t gfp);
extern void spi_res_add(struct spi_message *message, void *res);
extern void spi_res_free(void *res);
extern void spi_res_release(struct spi_master *master,
struct spi_message *message);
/*---------------------------------------------------------------------------*/
/*
* 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
* @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.
* @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
* @tx_sg: Scatterlist for transmit, currently not for client use
* @rx_sg: Scatterlist for receive, currently not for client use
*
* 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.
*
* 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 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;
struct sg_table tx_sg;
struct sg_table rx_sg;
unsigned cs_change:1;
unsigned tx_nbits:3;
unsigned rx_nbits:3;
#define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */
#define SPI_NBITS_DUAL 0x02 /* 2bits transfer */
#define SPI_NBITS_QUAD 0x04 /* 4bits transfer */
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
* @frame_length: the total number of bytes in the message
* @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
* @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
* 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 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;
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 frame_length;
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;
/* list of spi_res reources 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);
}
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static inline void spi_message_init(struct spi_message *m)
{
memset(m, 0, sizeof *m);
spi_message_init_no_memset(m);
}
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static inline void
spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
{
list_add_tail(&t->transfer_list, &m->transfers);
}
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static inline void
spi_transfer_del(struct spi_transfer *t)
{
list_del(&t->transfer_list);
}
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/**
* 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);
}
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/* 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);
spi_message_init_no_memset(m);
for (i = 0; i < ntrans; i++, t++)
spi_message_add_tail(t, m);
}
return m;
}
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static inline void spi_message_free(struct spi_message *m)
{
kfree(m);
}
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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);
static inline size_t
spi_max_message_size(struct spi_device *spi)
{
struct spi_master *master = spi->master;
if (!master->max_message_size)
return SIZE_MAX;
return master->max_message_size(spi);
}
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static inline size_t
spi_max_transfer_size(struct spi_device *spi)
{
struct spi_master *master = spi->master;
size_t tr_max = SIZE_MAX;
size_t msg_max = spi_max_message_size(spi);
if (master->max_transfer_size)
tr_max = master->max_transfer_size(spi);
/* transfer size limit must not be greater than messsage size limit */
return min(tr_max, msg_max);
}
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/*---------------------------------------------------------------------------*/
/* SPI transfer replacement methods which make use of spi_res */
struct spi_replaced_transfers;
typedef void (*spi_replaced_release_t)(struct spi_master *master,
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
* relasing 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[];
};
extern struct spi_replaced_transfers *spi_replace_transfers(
struct spi_message *msg,
struct spi_transfer *xfer_first,
size_t remove,
size_t insert,
spi_replaced_release_t release,
size_t extradatasize,
gfp_t gfp);
/*---------------------------------------------------------------------------*/
/* SPI transfer transformation methods */
extern int spi_split_transfers_maxsize(struct spi_master *master,
struct spi_message *msg,
size_t maxsize,
gfp_t gfp);
/*---------------------------------------------------------------------------*/
/* 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_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: 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);
}
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/**
* 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);
}
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/**
* 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);
}
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/* 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;
}
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/**
* 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;
}
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/**
* 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);
}
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/**
* struct spi_flash_read_message - flash specific information for
* spi-masters that provide accelerated flash read interfaces
* @buf: buffer to read data
* @from: offset within the flash from where data is to be read
* @len: length of data to be read
* @retlen: actual length of data read
* @read_opcode: read_opcode to be used to communicate with flash
* @addr_width: number of address bytes
* @dummy_bytes: number of dummy bytes
* @opcode_nbits: number of lines to send opcode
* @addr_nbits: number of lines to send address
* @data_nbits: number of lines for data
* @rx_sg: Scatterlist for receive data read from flash
* @cur_msg_mapped: message has been mapped for DMA
*/
struct spi_flash_read_message {
void *buf;
loff_t from;
size_t len;
size_t retlen;
u8 read_opcode;
u8 addr_width;
u8 dummy_bytes;
u8 opcode_nbits;
u8 addr_nbits;
u8 data_nbits;
struct sg_table rx_sg;
bool cur_msg_mapped;
};
/* SPI core interface for flash read support */
static inline bool spi_flash_read_supported(struct spi_device *spi)
{
return spi->master->spi_flash_read &&
(!spi->master->flash_read_supported ||
spi->master->flash_read_supported(spi));
}
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int spi_flash_read(struct spi_device *spi,
struct spi_flash_read_message *msg);
/*---------------------------------------------------------------------------*/
/*
* 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.
* @properties: Additional device properties 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_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,
* device properties are copied and attached to spi_device,
* irq is copied too
*/
char modalias[SPI_NAME_SIZE];
const void *platform_data;
const struct property_entry *properties;
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.
*/
u16 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; }
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Brownell | 19 | 100.00% | 1 | 100.00% |
| Total | 19 | 100.00% | 1 | 100.00% |
#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 *);
extern void spi_unregister_device(struct spi_device *spi);
extern const struct spi_device_id *
spi_get_device_id(const struct spi_device *sdev);
static inline bool
spi_transfer_is_last(struct spi_master *master, struct spi_transfer *xfer)
{
return list_is_last(&xfer->transfer_list, &master->cur_msg->transfers);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Beniamino Galvani | 33 | 100.00% | 1 | 100.00% |
| Total | 33 | 100.00% | 1 | 100.00% |
#endif /* __LINUX_SPI_H */
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Brownell | 1058 | 38.68% | 14 | 17.28% |
| Martin Sperl | 374 | 13.67% | 7 | 8.64% |
| Mark Brown | 211 | 7.71% | 12 | 14.81% |
| Lars-Peter Clausen | 141 | 5.16% | 4 | 4.94% |
| Linus Walleij | 126 | 4.61% | 1 | 1.23% |
| Vitaly Wool | 120 | 4.39% | 1 | 1.23% |
| Vignesh R | 116 | 4.24% | 3 | 3.70% |
| Heiner Kallweit | 103 | 3.77% | 2 | 2.47% |
| Ernst Schwab | 62 | 2.27% | 1 | 1.23% |
| Michal Suchanek | 49 | 1.79% | 1 | 1.23% |
| Geert Uytterhoeven | 49 | 1.79% | 2 | 2.47% |
| Ben Dooks | 49 | 1.79% | 1 | 1.23% |
| wangyuhang | 41 | 1.50% | 1 | 1.23% |
| Beniamino Galvani | 33 | 1.21% | 1 | 1.23% |
| Anton Vorontsov | 30 | 1.10% | 2 | 2.47% |
| Stephen Warren | 27 | 0.99% | 5 | 6.17% |
| Grant C. Likely | 25 | 0.91% | 2 | 2.47% |
| Andy Shevchenko | 16 | 0.59% | 1 | 1.23% |
| Andrew F. Davis | 15 | 0.55% | 1 | 1.23% |
| Mika Westerberg | 15 | 0.55% | 1 | 1.23% |
| Dmitry Torokhov | 11 | 0.40% | 1 | 1.23% |
| Tony Jones | 10 | 0.37% | 1 | 1.23% |
| Jean-Christophe Plagniol-Villard | 9 | 0.33% | 1 | 1.23% |
| Imre Deak | 6 | 0.22% | 1 | 1.23% |
| Andrew Morton | 6 | 0.22% | 1 | 1.23% |
| Thor Thayer | 5 | 0.18% | 1 | 1.23% |
| Mike Rapoport | 4 | 0.15% | 1 | 1.23% |
| Feng Tang | 4 | 0.15% | 1 | 1.23% |
| Javier Martinez Canillas | 4 | 0.15% | 2 | 2.47% |
| Trent Piepho | 3 | 0.11% | 1 | 1.23% |
| Randy Dunlap | 3 | 0.11% | 1 | 1.23% |
| Sourav Poddar | 3 | 0.11% | 1 | 1.23% |
| Tejun Heo | 3 | 0.11% | 1 | 1.23% |
| Shubhrajyoti Datta | 1 | 0.04% | 1 | 1.23% |
| Linus Torvalds | 1 | 0.04% | 1 | 1.23% |
| Jarkko Nikula | 1 | 0.04% | 1 | 1.23% |
| Emiliano Ingrassia | 1 | 0.04% | 1 | 1.23% |
| Total | 2735 | 100.00% | 81 | 100.00% |
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