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spi_alloc_master(9) [centos man page]

SPI_ALLOC_MASTER(9)					  Serial Peripheral Interface (S				       SPI_ALLOC_MASTER(9)

spi_alloc_master - allocate SPI master controller SYNOPSIS
struct spi_master * spi_alloc_master(struct device * dev, unsigned size); ARGUMENTS
dev the controller, possibly using the platform_bus size how much zeroed driver-private data to allocate; the pointer to this memory is in the driver_data field of the returned device, accessible with spi_master_get_devdata. CONTEXT
This call is used only by SPI master controller drivers, which are the only ones directly touching chip registers. It's how they allocate an spi_master structure, prior to calling spi_register_master. This must be called from context that can sleep. It returns the SPI master structure on success, else NULL. The caller is responsible for assigning the bus number and initializing the master's methods before calling spi_register_master; and (after errors adding the device) calling spi_master_put and kfree to prevent a memory leak. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 SPI_ALLOC_MASTER(9)

Check Out this Related Man Page

SPI_DEVICE(9) Serial Peripheral Interface (S STRUCT SPI_DEVICE(9) NAME
struct_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. COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 STRUCT SPI_DEVICE(9)
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