251 lines
7.0 KiB
C
251 lines
7.0 KiB
C
/*
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* Copyright (c) 2015 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @file
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* @brief Public API for SPI drivers
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*/
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#ifndef __SPI_H__
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#define __SPI_H__
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/**
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* @brief SPI Interface
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* @defgroup spi_interface SPI Interface
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* @ingroup io_interfaces
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* @{
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*/
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#include <stdint.h>
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#include <stddef.h>
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#include <device.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief SPI Polarity & Phase Modes
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*/
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#define SPI_MODE_CPOL 0x1
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#define SPI_MODE_CPHA 0x2
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#define SPI_MODE_LOOP 0x4
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#define SPI_MODE_MASK (0x7)
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#define SPI_MODE(_in_) ((_in_) & SPI_MODE_MASK)
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/**
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* @brief SPI Transfer modes (host controller dependent)
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*/
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#define SPI_TRANSFER_MSB (0 << 3)
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#define SPI_TRANSFER_LSB (1 << 3)
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#define SPI_TRANSFER_MASK (0x8)
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#define SPI_WORD_SIZE_MASK (0xFF << 4)
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#define SPI_WORD_SIZE_GET(_in_) (((_in_) & SPI_WORD_SIZE_MASK) >> 4)
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#define SPI_WORD(_in_) ((_in_) << 4)
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/**
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* @brief SPI configuration structure.
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*
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* config is a bit field with the following parts:
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* mode [ 0 : 2 ] - Polarity, phase and loop mode.
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* transfer_mode [ 3 ] - LSB or MSB first transfer mode.
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* word_size [ 4 : 11 ] - Size of a data frame in bits.
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* RESERVED [ 12 : 31 ] - Undefined or device-specific usage.
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*
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* max_sys_freq is the maximum frequency supported by the slave it
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* will deal with. This value depends on the host controller. The driver
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* can present a specific format for setting it.
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*/
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struct spi_config {
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uint32_t config;
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uint32_t max_sys_freq;
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};
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/**
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* @typedef spi_api_configure
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* @brief Callback API upon configuring the const controller
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* See spi_configure() for argument description
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*/
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typedef int (*spi_api_configure)(struct device *dev,
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struct spi_config *config);
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/**
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* @typedef spi_api_slave_select
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* @brief Callback API upon selecting a slave
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* See spi_slave_select() for argument description
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*/
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typedef int (*spi_api_slave_select)(struct device *dev, uint32_t slave);
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/**
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* @typedef spi_api_io
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* @brief Callback API for I/O
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* See spi_read() and spi_write() for argument descriptions
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*/
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typedef int (*spi_api_io)(struct device *dev,
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const void *tx_buf, uint32_t tx_buf_len,
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void *rx_buf, uint32_t rx_buf_len);
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/**
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* @typedef spi_api_control
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* @brief Callback API upon for suspend/resume
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* See spi_suspend() and spi_resume() for argument description
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*/
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typedef int (*spi_api_control)(struct device *dev);
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struct spi_driver_api {
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spi_api_configure configure;
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spi_api_slave_select slave_select;
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spi_api_io transceive;
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spi_api_control suspend;
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spi_api_control resume;
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};
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/**
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* @brief Configure a host controller for operating against slaves.
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* @param dev Pointer to the device structure for the driver instance.
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* @param config Pointer to the configuration provided by the application.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_configure(struct device *dev,
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struct spi_config *config)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->configure(dev, config);
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}
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/**
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* @brief Select a slave to deal with.
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*
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* This routine is meaningful only if the controller supports per-slave
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* addressing: One SS line per-slave. If not, this routine has no effect
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* and daisy-chaining should be considered to deal with multiple slaves
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* on the same line.
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*
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* @param dev Pointer to the device structure for the driver instance
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* @param slave An integer identifying the slave. It starts from 1 which
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* corresponds to cs0.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_slave_select(struct device *dev, uint32_t slave)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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if (!api->slave_select) {
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return 0;
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}
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return api->slave_select(dev, slave);
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}
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/**
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* @brief Read the specified amount of data from the SPI driver.
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* @param dev Pointer to the device structure for the driver instance.
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* @param buf Memory buffer where data will be transferred.
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* @param len Size of the memory buffer available for writing.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_read(struct device *dev, void *buf, uint32_t len)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->transceive(dev, NULL, 0, buf, len);
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}
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/**
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* @brief Write the specified amount of data from the SPI driver.
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* @param dev Pointer to the device structure for the driver instance.
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* @param buf Memory buffer from where data is transferred.
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* @param len Size of the memory buffer available for reading.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_write(struct device *dev, const void *buf, uint32_t len)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->transceive(dev, buf, len, NULL, 0);
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}
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/**
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* @brief Read and write the specified amount of data from the SPI driver.
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*
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* This routine is meant for full-duplex transmission.
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* Only equal length is supported(tx_buf_len must be equal to rx_buf_len).
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*
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* @param dev Pointer to the device structure for the driver instance.
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* @param tx_buf Memory buffer where data originates
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* @param tx_buf_len Size of the memory buffer available for reading.
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* @param rx_buf Memory buffer where data is transferred.
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* @param rx_buf_len Size of the memory buffer available for writing.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_transceive(struct device *dev,
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const void *tx_buf, uint32_t tx_buf_len,
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void *rx_buf, uint32_t rx_buf_len)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->transceive(dev, tx_buf, tx_buf_len, rx_buf, rx_buf_len);
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}
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/**
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* @brief Suspend the SPI host controller operations.
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* @param dev Pointer to the device structure for the driver instance.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_suspend(struct device *dev)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->suspend(dev);
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}
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/**
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* @brief Resume the SPI host controller operations.
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* @param dev Pointer to the device structure for the driver instance.
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*
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* @retval 0 If successful.
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* @retval Negative errno code if failure.
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*/
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static inline int spi_resume(struct device *dev)
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{
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struct spi_driver_api *api = (struct spi_driver_api *)dev->driver_api;
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return api->resume(dev);
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}
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#ifdef __cplusplus
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}
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#endif
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/**
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* @}
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*/
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#endif /* __SPI_H__ */
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