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160 lines
4.0 KiB
160 lines
4.0 KiB
/**************************************************************************** |
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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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