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Diffstat (limited to 'libmaple/spi.c')
| -rw-r--r-- | libmaple/spi.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/libmaple/spi.c b/libmaple/spi.c new file mode 100644 index 0000000..194a82e --- /dev/null +++ b/libmaple/spi.c @@ -0,0 +1,164 @@ +/****************************************************************************** + * 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); +} |