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Add a general bit-bang SPI upper-half driver
This commit is contained in:
Gregory Nutt
Executable
+176
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/****************************************************************************
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* include/nuttx/spi/spi_bitbang.h
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*
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* Copyright (C) 2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __INCLUDE_NUTTX_SPI_SPI_BITBANG_H
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#define __INCLUDE_NUTTX_SPI_SPI_BITBANG_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/spi/spi.h>
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#ifdef CONFIG_SPI_BITBANG
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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#ifndef SPI_BITBANG_MODE <<< NOOOO.. Needs to be programmable
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# define SPI_BITBANG_MODE SPI_MODE0
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#endif
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#ifndef CONFIG_SPI_BITBANG_FREQUENCY <<< NOOOO.. Needs to be programmable
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# define CONFIG_SPI_BITBANG_FREQUENCY 1000000
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#endif
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/* Debug ********************************************************************/
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/* Check if SPI debut is enabled (non-standard.. no support in
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* include/debug.h
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*/
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#ifndef CONFIG_DEBUG
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# undef CONFIG_DEBUG_VERBOSE
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# undef CONFIG_DEBUG_SPI
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#endif
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#ifdef CONFIG_DEBUG_SPI
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# define spidbg lldbg
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# ifdef CONFIG_DEBUG_VERBOSE
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# define spivdbg lldbg
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# else
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# define spivdbg(x...)
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# endif
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#else
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# define spidbg(x...)
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# define spivdbg(x...)
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#endif
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/****************************************************************************
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* Private Types
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****************************************************************************/
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#ifndef __ASSEMBLY__
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/* These are the lower-half handlers that perform the level-level, platform-
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* specific bit-bang operations.
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*/
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struct spi_bitbang_s; /* Forward reference */
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struct spi_bitbang_ops_s
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{
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/* Platform specific chip select logic */
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void (*select)(FAR struct spi_bitbang_s *priv, enum spi_dev_e devid,
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bool selected);
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/* Platform-specific, SPI mode function */
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void (*setmode)(FAR struct spi_bitbang_s *priv, enum spi_mode_e mode);
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/* Platform-specific word exchange function */
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uint16_t (*exchange)(FAR struct spi_bitbang_s *priv, uint16_t dataout);
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/* Platform-specific word exchange function */
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uint8_t (*status)(FAR struct spi_bitbang_s *priv, enum spi_dev_e devid);
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#ifdef CONFIG_SPI_CMDDATA
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/* Platform-specific CMD/DATA function */
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int (*cmddata)(FAR struct spi_bitbang_s *priv, enum spi_dev_e devid,
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bool cmd);
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#endif
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};
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/* This structure provides the state of the SPI bit-bang driver */
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struct spi_bitbang_s
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{
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struct spi_dev_s dev; /* Publicly visible version of SPI driver */
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FAR const struct spi_bitbang_ops_s *low; /* Low-level operations */
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uint32_t hpnsec; /* Number of microseconds in a half cycle */
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#ifndef CONFIG_SPI_OWNBUS
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sem_t exclsem; /* Supports mutually exclusive access to SPI */
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#endif
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#ifdef CONFIG_SPI_BITBANG_VARWIDTH
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uint8_t nbits; /* Number of bits in the transfer */
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#endif
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FAR void *priv; /* For use by the lower half driver */
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#undef EXTERN
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#if defined(__cplusplus)
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: spi_create_bitbang
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*
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* Descripton:
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* Create an instance of the SPI bit-bang driver.
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*
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* Input Parameters:
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* low - Low-level, platform specific device operations.
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*
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* Returned Value:
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* On success a non-NULL, initialized SPI driver instance is returned.
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*
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****************************************************************************/
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FAR struct spi_dev_s *spi_create_bitbang(FAR const struct spi_bitbang_ops_s *low);
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#undef EXTERN
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#if defined(__cplusplus)
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}
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* CONFIG_SPI_BITBANG */
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#endif /* __INCLUDE_NUTTX_SPI_SPI_BITBANG_H */
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