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/**
* @file spi.h
*
* @ingroup raspberrypi_spi
*
* @brief Raspberry Pi specific SPI definitions.
*/
/*
* Copyright (c) 2014-2015 Andre Marques <andre.lousa.marques at gmail.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifndef LIBBSP_ARM_RASPBERRYPI_SPI_H
#define LIBBSP_ARM_RASPBERRYPI_SPI_H
#include <rtems/libi2c.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/**
* @name SPI constants.
*
* @{
*/
/**
* @brief GPU processor core clock rate in Hz.
*
* Unless configured otherwise on a "config.txt" file present on the SD card
* the GPU defaults to 250 MHz. Currently only 250 MHz is supported.
*/
/* TODO: It would be nice if this value could be probed at startup, probably
* using the Mailbox interface since the usual way of setting this on
* the hardware is through a "config.txt" text file on the SD card.
* Having this setup on the configure.ac script would require changing
* the same setting on two different places. */
#define GPU_CORE_CLOCK_RATE 250000000
/** @} */
/**
* @name SPI directives.
*
* @{
*/
/**
* @brief Setups the Raspberry Pi SPI bus (located on the GPIO header)
* on the "/dev/spi" device file, and registers the bus on the
* libi2c API.
*
* @param[in] bidirectional_mode If TRUE sets the SPI bus to use 2-wire SPI,
* where the MOSI data line doubles as the
* slave out (SO) and slave in (SI) data lines.
* If FALSE the bus defaults to the usual
* 3-wire SPI, with 2 separate data lines
* (MOSI and MISO).
*
* @retval Returns libi2c bus number.
* @retval <0 Could not register the bus. See @see rtems_libi2c_register_bus().
*/
extern int rpi_spi_init(bool bidirectional_mode);
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* LIBBSP_ARM_RASPBERRYPI_SPI_H */
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