forked from Archive/PX4-Autopilot
161 lines
4.0 KiB
C++
161 lines
4.0 KiB
C++
/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. All rights reserved.
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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 PX4 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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/**
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* @file spi.cpp
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*
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* Base class for devices connected via SPI.
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*
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* @todo Work out if caching the mode/frequency would save any time.
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*
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* @todo A separate bus/device abstraction would allow for mixed interrupt-mode
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* and non-interrupt-mode clients to arbitrate for the bus. As things stand,
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* a bus shared between clients of both kinds is vulnerable to races between
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* the two, where an interrupt-mode client will ignore the lock held by the
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* non-interrupt-mode client.
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*/
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#include <nuttx/arch.h>
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#include "spi.h"
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#ifndef CONFIG_SPI_EXCHANGE
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# error This driver requires CONFIG_SPI_EXCHANGE
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#endif
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namespace device
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{
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SPI::SPI(const char *name,
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const char *devname,
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int bus,
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enum spi_dev_e device,
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enum spi_mode_e mode,
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uint32_t frequency,
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int irq) :
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// base class
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CDev(name, devname, irq),
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// public
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// protected
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// private
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_bus(bus),
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_device(device),
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_mode(mode),
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_frequency(frequency),
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_dev(nullptr)
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{
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}
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SPI::~SPI()
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{
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// XXX no way to let go of the bus...
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}
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int
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SPI::init()
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{
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int ret = OK;
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/* attach to the spi bus */
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if (_dev == nullptr)
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_dev = up_spiinitialize(_bus);
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if (_dev == nullptr) {
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debug("failed to init SPI");
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ret = -ENOENT;
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goto out;
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}
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/* deselect device to ensure high to low transition of pin select */
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SPI_SELECT(_dev, _device, false);
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/* call the probe function to check whether the device is present */
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ret = probe();
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if (ret != OK) {
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debug("probe failed");
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goto out;
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}
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/* do base class init, which will create the device node, etc. */
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ret = CDev::init();
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if (ret != OK) {
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debug("cdev init failed");
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goto out;
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}
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/* tell the workd where we are */
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log("on SPI bus %d at %d", _bus, _device);
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out:
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return ret;
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}
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int
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SPI::probe()
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{
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// assume the device is too stupid to be discoverable
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return OK;
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}
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int
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SPI::transfer(uint8_t *send, uint8_t *recv, unsigned len)
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{
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if ((send == nullptr) && (recv == nullptr))
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return -EINVAL;
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/* do common setup */
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if (!up_interrupt_context())
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SPI_LOCK(_dev, true);
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SPI_SETFREQUENCY(_dev, _frequency);
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SPI_SETMODE(_dev, _mode);
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SPI_SETBITS(_dev, 8);
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SPI_SELECT(_dev, _device, true);
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/* do the transfer */
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SPI_EXCHANGE(_dev, send, recv, len);
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/* and clean up */
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SPI_SELECT(_dev, _device, false);
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if (!up_interrupt_context())
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SPI_LOCK(_dev, false);
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return OK;
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}
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} // namespace device
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