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/**
* @file
*
* @brief Serial Peripheral Interface (SPI) Driver API
*
* @ingroup SPI
*/
/*
* Copyright (c) 2016 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* 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 _DEV_SPI_SPI_H
#define _DEV_SPI_SPI_H
#include <linux/spi/spidev.h>
#include <rtems.h>
#include <rtems/seterr.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
typedef struct spi_ioc_transfer spi_ioc_transfer;
typedef struct spi_bus spi_bus;
/**
* @defgroup SPI Serial Peripheral Interface (SPI) Driver
*
* @brief Serial Peripheral Interface (SPI) bus driver support.
*
* @{
*/
/**
* @brief Obtains the bus.
*
* This command has no argument.
*/
#define SPI_BUS_OBTAIN _IO(SPI_IOC_MAGIC, 13)
/**
* @brief Releases the bus.
*
* This command has no argument.
*/
#define SPI_BUS_RELEASE _IO(SPI_IOC_MAGIC, 23)
/**
* @brief SPI bus control.
*/
struct spi_bus {
/**
* @brief Transfers SPI messages.
*
* @param[in] bus The bus control.
* @param[in] msgs The messages to transfer.
* @param[in] msg_count The count of messages to transfer. It must be
* positive.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int (*transfer)(spi_bus *bus, const spi_ioc_transfer *msgs, uint32_t msg_count);
/**
* @brief Checks if maximum speed and bits per word are in a valid range
* for the device
*
* @param[in] bus The bus control.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int (*setup)(spi_bus *bus);
/**
* @brief Destroys the bus.
*
* @param[in] bus The bus control.
*/
void (*destroy)(spi_bus *bus);
/**
* @brief Mutex to protect the bus access.
*/
rtems_id mutex;
/**
* @brief Maximum Speed in Hz
*/
uint32_t max_speed_hz;
/**
* @brief Indicates the speed of the current device message.
*/
uint32_t speed_hz;
/**
* @brief Indicates if chip select must be set high after transfer.
*/
bool cs_change;
/**
* @brief Indicates which device is selected by chip select
*/
uint8_t cs;
/**
* @brief Indicates the bits per word used on the device.
*/
uint8_t bits_per_word;
/**
* @brief Indicates if LSB is supposed to be transmitted first.
*/
bool lsb_first;
/**
* @brief Current mode.
*/
uint32_t mode;
/**
* @brief Indicates the delay between transfers on different chip select
* devices.
*/
uint16_t delay_usecs;
};
/**
* @brief Initializes a bus control.
*
* After a sucessful initialization the bus control must be destroyed via
* spi_bus_destroy(). A registered bus control will be automatically destroyed
* in case the device file is unlinked. Make sure to call spi_bus_destroy() in
* a custom destruction handler.
*
* @param[in] bus The bus control.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*
* @see spi_bus_register()
*/
int spi_bus_init(spi_bus *bus);
/**
* @brief Allocates a bus control from the heap and initializes it.
*
* After a sucessful allocation and initialization the bus control must be
* destroyed via spi_bus_destroy_and_free(). A registered bus control will be
* automatically destroyed in case the device file is unlinked. Make sure to
* call spi_bus_destroy_and_free() in a custom destruction handler.
*
* @param[in] size The size of the bus control. This enables the addition of
* bus controller specific data to the base bus control. The bus control is
* zero initialized.
*
* @retval non-NULL The new bus control.
* @retval NULL An error occurred. The errno is set to indicate the error.
*
* @see spi_bus_register()
*/
spi_bus *spi_bus_alloc_and_init(size_t size);
/**
* @brief Destroys a bus control.
*
* @param[in] bus The bus control.
*/
void spi_bus_destroy(spi_bus *bus);
/**
* @brief Destroys a bus control and frees its memory.
*
* @param[in] bus The bus control.
*/
void spi_bus_destroy_and_free(spi_bus *bus);
/**
* @brief Registers a bus control.
*
* This function claims ownership of the bus control regardless if the
* registration is successful or not.
*
* @param[in] bus The bus control.
* @param[in] bus_path The path to the bus device file.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*/
int spi_bus_register(
spi_bus *bus,
const char *bus_path
);
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _DEV_SPI_SPI_H */
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