spi_bitbang.h File Reference

#include <linux/workqueue.h>

Go to the source code of this file.

Data Structures
struct	spi_bitbang

Macros
#define	BITBANG_CS_ACTIVE   1 /* normally nCS, active low */
#define	BITBANG_CS_INACTIVE   0

Functions
int	spi_bitbang_setup (struct spi_device *spi)
void	spi_bitbang_cleanup (struct spi_device *spi)
int	spi_bitbang_transfer (struct spi_device *spi, struct spi_message *m)
int	spi_bitbang_setup_transfer (struct spi_device *spi, struct spi_transfer *t)
int	spi_bitbang_start (struct spi_bitbang *spi)
int	spi_bitbang_stop (struct spi_bitbang *spi)

Macro Definition Documentation

#define BITBANG_CS_ACTIVE   1 /* normally nCS, active low */

Definition at line 25 of file spi_bitbang.h.

#define BITBANG_CS_INACTIVE   0

Definition at line 26 of file spi_bitbang.h.

Function Documentation

void spi_bitbang_cleanup

(

struct spi_device *

spi

)

spi_bitbang_cleanup - default cleanup for per-word I/O loops

Definition at line 231 of file spi-bitbang.c.

int spi_bitbang_setup

(

struct spi_device *

spi

)

spi_bitbang_setup - default setup for per-word I/O loops

Definition at line 184 of file spi-bitbang.c.

int spi_bitbang_setup_transfer	(	struct spi_device *	spi,
		struct spi_transfer *	t
	)

Definition at line 142 of file spi-bitbang.c.

int spi_bitbang_start

(

struct spi_bitbang *

bitbang

)

spi_bitbang_start - start up a polled/bitbanging SPI master driver : driver handle

Caller should have zero-initialized all parts of the structure, and then provided callbacks for chip selection and I/O loops. If the master has a transfer method, its final step should call spi_bitbang_transfer; or, that's the default if the transfer routine is not initialized. It should also set up the bus number and number of chipselects.

For i/o loops, provide callbacks either per-word (for bitbanging, or for hardware that basically exposes a shift register) or per-spi_transfer (which takes better advantage of hardware like fifos or DMA engines).

Drivers using per-word I/O loops should use (or call) spi_bitbang_setup, spi_bitbang_cleanup and spi_bitbang_setup_transfer to handle those spi master methods. Those methods are the defaults if the bitbang->txrx_bufs routine isn't initialized.

This routine registers the spi_master, which will process requests in a dedicated task, keeping IRQs unblocked most of the time. To stop processing those requests, call spi_bitbang_stop().

Definition at line 433 of file spi-bitbang.c.

int spi_bitbang_stop

(

struct spi_bitbang *

bitbang

)

spi_bitbang_stop - stops the task providing spi communication

Definition at line 493 of file spi-bitbang.c.

int spi_bitbang_transfer	(	struct spi_device *	spi,
		struct spi_message *	m
	)

spi_bitbang_transfer - default submit to transfer queue

Definition at line 384 of file spi-bitbang.c.