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/******************************************************************************
* The MIT License
*
* Copyright (c) 2011, 2012 LeafLabs, LLC.
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file libmaple/spi.c
* @author Marti Bolivar <mbolivar@leaflabs.com>
* @brief Serial Peripheral Interface (SPI) support.
* Currently, there is no Integrated Interchip Sound (I2S) support.
*/
#include <libmaple/spi.h>
#include <libmaple/bitband.h>
static void spi_reconfigure(spi_dev *dev, uint32 cr1_config);
/*
* SPI convenience routines
*/
/**
* @brief Initialize and reset a SPI device.
* @param dev Device to initialize and reset.
*/
void spi_init(spi_dev *dev) {
rcc_clk_enable(dev->clk_id);
rcc_reset_dev(dev->clk_id);
}
/**
* @brief Configure and enable a SPI device as bus master.
*
* The device's peripheral will be disabled before being reconfigured.
*
* @param dev Device to configure as bus master
* @param baud Bus baud rate
* @param mode SPI mode
* @param flags Logical OR of spi_cfg_flag values.
* @see spi_cfg_flag
*/
void spi_master_enable(spi_dev *dev,
spi_baud_rate baud,
spi_mode mode,
uint32 flags) {
spi_reconfigure(dev, baud | flags | SPI_CR1_MSTR | mode);
}
/**
* @brief Configure and enable a SPI device as a bus slave.
*
* The device's peripheral will be disabled before being reconfigured.
*
* @param dev Device to configure as a bus slave
* @param mode SPI mode
* @param flags Logical OR of spi_cfg_flag values.
* @see spi_cfg_flag
*/
void spi_slave_enable(spi_dev *dev, spi_mode mode, uint32 flags) {
spi_reconfigure(dev, flags | mode);
}
/**
* @brief Nonblocking SPI transmit.
* @param dev SPI port to use for transmission
* @param buf Buffer to transmit. The sizeof buf's elements are
* inferred from dev's data frame format (i.e., are
* correctly treated as 8-bit or 16-bit quantities).
* @param len Maximum number of elements to transmit.
* @return Number of elements transmitted.
*/
uint32 spi_tx(spi_dev *dev, const void *buf, uint32 len) {
uint32 txed = 0;
uint8 byte_frame = spi_dff(dev) == SPI_DFF_8_BIT;
while (spi_is_tx_empty(dev) && (txed < len)) {
if (byte_frame) {
dev->regs->DR = ((const uint8*)buf)[txed++];
} else {
dev->regs->DR = ((const uint16*)buf)[txed++];
}
}
return txed;
}
/**
* @brief Enable a SPI peripheral
* @param dev Device to enable
*/
void spi_peripheral_enable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR1, SPI_CR1_SPE_BIT, 1);
}
/**
* @brief Disable a SPI peripheral
* @param dev Device to disable
*/
void spi_peripheral_disable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR1, SPI_CR1_SPE_BIT, 0);
}
/**
* @brief Enable DMA requests whenever the transmit buffer is empty
* @param dev SPI device on which to enable TX DMA requests
*/
void spi_tx_dma_enable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR2, SPI_CR2_TXDMAEN_BIT, 1);
}
/**
* @brief Disable DMA requests whenever the transmit buffer is empty
* @param dev SPI device on which to disable TX DMA requests
*/
void spi_tx_dma_disable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR2, SPI_CR2_TXDMAEN_BIT, 0);
}
/**
* @brief Enable DMA requests whenever the receive buffer is empty
* @param dev SPI device on which to enable RX DMA requests
*/
void spi_rx_dma_enable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR2, SPI_CR2_RXDMAEN_BIT, 1);
}
/**
* @brief Disable DMA requests whenever the receive buffer is empty
* @param dev SPI device on which to disable RX DMA requests
*/
void spi_rx_dma_disable(spi_dev *dev) {
bb_peri_set_bit(&dev->regs->CR2, SPI_CR2_RXDMAEN_BIT, 0);
}
/*
* SPI auxiliary routines
*/
static void spi_reconfigure(spi_dev *dev, uint32 cr1_config) {
spi_irq_disable(dev, SPI_INTERRUPTS_ALL);
spi_peripheral_disable(dev);
dev->regs->CR1 = cr1_config;
spi_peripheral_enable(dev);
}
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