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- /****************************************************************************
- * include/nuttx/spi/spi_bitbang.h
- *
- * Copyright (C) 2013 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- * 3. Neither the name NuttX nor the names of its contributors may be
- * used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
- #ifndef __INCLUDE_NUTTX_SPI_SPI_BITBANG_H
- #define __INCLUDE_NUTTX_SPI_SPI_BITBANG_H
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <nuttx/semaphore.h>
- #include <nuttx/spi/spi.h>
- #ifdef CONFIG_SPI_BITBANG
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- #ifndef __ASSEMBLY__
- /* These are the lower-half handlers that perform the level-level, platform-
- * specific bit-bang operations.
- */
- struct spi_bitbang_s; /* Forward reference */
- struct spi_bitbang_ops_s
- {
- /* Platform specific chip select logic */
- void (*select)(FAR struct spi_bitbang_s *priv, uint32_t devid,
- bool selected);
- /* Platform-specific, SPI frequency function */
- uint32_t (*setfrequency)(FAR struct spi_bitbang_s *priv,
- uint32_t frequency);
- /* Platform-specific, SPI mode function */
- void (*setmode)(FAR struct spi_bitbang_s *priv, enum spi_mode_e mode);
- /* Platform-specific word exchange function */
- uint16_t (*exchange)(FAR struct spi_bitbang_s *priv, uint16_t dataout);
- /* Platform-specific word exchange function */
- uint8_t (*status)(FAR struct spi_bitbang_s *priv, uint32_t devid);
- #ifdef CONFIG_SPI_CMDDATA
- /* Platform-specific CMD/DATA function */
- int (*cmddata)(FAR struct spi_bitbang_s *priv, uint32_t devid,
- bool cmd);
- #endif
- };
- /* This is the type of the function that can exchange one bit */
- typedef CODE uint8_t (*bitexchange_t)(uint8_t dataout, uint32_t holdtime);
- /* This structure provides the state of the SPI bit-bang driver */
- struct spi_bitbang_s
- {
- struct spi_dev_s dev; /* Publicly visible version of SPI driver */
- FAR const struct spi_bitbang_ops_s *low; /* Low-level operations */
- uint32_t holdtime; /* SCK hold time to achieve requested frequency */
- bitexchange_t exchange; /* The select bit exchange function */
- sem_t exclsem; /* Supports mutually exclusive access to SPI */
- #ifdef CONFIG_SPI_BITBANG_VARWIDTH
- uint8_t nbits; /* Number of bits in the transfer */
- #endif
- };
- /****************************************************************************
- * Public Data
- ****************************************************************************/
- #undef EXTERN
- #if defined(__cplusplus)
- #define EXTERN extern "C"
- extern "C"
- {
- #else
- #define EXTERN extern
- #endif
- /****************************************************************************
- * Public Function Prototypes
- ****************************************************************************/
- /****************************************************************************
- * Name: spi_create_bitbang
- *
- * Description:
- * Create an instance of the SPI bit-bang driver.
- *
- * Input Parameters:
- * low - Low-level, platform specific device operations.
- *
- * Returned Value:
- * On success a non-NULL, initialized SPI driver instance is returned.
- *
- ****************************************************************************/
- FAR struct spi_dev_s *spi_create_bitbang(FAR const struct spi_bitbang_ops_s *low);
- #undef EXTERN
- #if defined(__cplusplus)
- }
- #endif
- #endif /* __ASSEMBLY__ */
- #endif /* CONFIG_SPI_BITBANG */
- #endif /* __INCLUDE_NUTTX_SPI_SPI_BITBANG_H */
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