forked from Imagelibrary/rtems
0e7567bc2a
The driver uses simple pin set or get functions to emulate an SPI. It doesn't care much for speed settings and just tries it's best.
138 lines
4.3 KiB
C
138 lines
4.3 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/**
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* @file
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*
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* @ingroup RTEMSDeviceSPIGPIO
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*
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* @brief This header file provides the interfaces of @ref RTEMSDeviceSPIGPIO.
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*/
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/*
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* Copyright (C) 2024 embedded brains GmbH & Co. KG
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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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* 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 the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN 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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#ifndef _RTEMS_DEV_SPI_SPI_GPIO_H
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#define _RTEMS_DEV_SPI_SPI_GPIO_H
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#include <rtems.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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/**
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* @defgroup RTEMSDeviceSPIGPIO
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*
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* @ingroup SPI
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*
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* @brief A simple SPI bus driver that just uses GPIO pins
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*
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* Implements a SPI that is emulated by toggling GPIO pins. Callbacks are used
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* to set or get the pins so that it can be easily adapted to various GPIO
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* controllers.
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*
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* NOTE: This driver is slow! If you need performance: Don't use it. The
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* intended use case is (for example) a one time configuration of some SPI
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* peripheral.
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*
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* The driver will just work as fast as it can. Setting a speed limit is
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* currently not supported.
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*
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* @{
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*/
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#define SPI_GPIO_MAX_CS 4
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/**
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* @brief Type of the functions that set pins
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*
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* Set a GPIO pin to @a level. @a level is false for low or true for high. @a
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* arg is an application specific parameter.
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*/
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typedef void (spi_gpio_set_pin_fn) (void *arg, bool level);
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/**
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* @brief Type of the functions that read pins
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*
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* Get current level of GPIO pin. Should return either 0 for low or anything
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* else for high. @a arg is an application specific parameter.
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*/
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typedef bool (spi_gpio_get_pin_fn) (void *arg);
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/**
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* @brief Parameters for the driver
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*
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* Parameters that should be provided by the application while registering the
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* driver. Mainly functions to set single pins.
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*/
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struct spi_gpio_params {
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/** Function for setting the clock pin */
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spi_gpio_set_pin_fn *set_clk;
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/** Application specific argument for the clock pin setter function */
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void *set_clk_arg;
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/** Function for setting the mosi pin */
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spi_gpio_set_pin_fn *set_mosi;
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/** Application specific argument for the mosi pin setter function */
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void *set_mosi_arg;
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/** Function for reading the miso pin */
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spi_gpio_get_pin_fn *get_miso;
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/** Application specific argument for the miso pin getter function */
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void *get_miso_arg;
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/** Functions for setting the cs pins */
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spi_gpio_set_pin_fn *set_cs[SPI_GPIO_MAX_CS];
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/** Application specific arguments for the cs pin getter functions */
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void *set_cs_arg[SPI_GPIO_MAX_CS];
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/**
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* Idle level of the CS pin.
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*
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* Set the value to 0 for a high active CS or to 1 for a low active CS pin.
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*/
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bool cs_idle[SPI_GPIO_MAX_CS];
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};
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/**
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* Register a new SPI GPIO instance at the device path @a device.
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*
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* To save memory, @a params will be used directly. Make sure that the structure
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* remains valid during the complete application run time.
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*
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* @returns RTEMS_SUCCESSFUL if registering the bus worked or an error code if
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* it didn't.
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*/
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rtems_status_code spi_gpio_init(
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const char *device,
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const struct spi_gpio_params *params
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);
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/** @} */
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* _RTEMS_DEV_SPI_SPI_GPIO_H */
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