STRUCT SPI_DEVICE(9) Serial Peripheral Interface (S STRUCT SPI_DEVICE(9)NAMEstruct_spi_device - Master side proxy for an SPI slave device
SYNOPSIS
struct spi_device {
struct device dev;
struct spi_master * master;
u32 max_speed_hz;
u8 chip_select;
u8 mode;
#define SPI_CPHA 0x01
#define SPI_CPOL 0x02
#define SPI_MODE_0 (0|0)
#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
#define SPI_LSB_FIRST 0x08
#define SPI_3WIRE 0x10
#define SPI_LOOP 0x20
#define SPI_NO_CS 0x40
#define SPI_READY 0x80
u8 bits_per_word;
int irq;
void * controller_state;
void * controller_data;
char modalias[SPI_NAME_SIZE];
};
MEMBERS
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[SPI_NAME_SIZE]
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
DESCRIPTION
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.
COPYRIGHTKernel Hackers Manual 2.6. November 2013 STRUCT SPI_DEVICE(9)
