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167 lines
3.9 KiB
167 lines
3.9 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 Base class for devices attached via the I2C bus. |
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* |
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* @todo Bus frequency changes; currently we do nothing with the value |
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* that is supplied. Should we just depend on the bus knowing? |
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*/ |
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#include "i2c.h" |
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namespace device |
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{ |
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I2C::I2C(const char *name, |
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const char *devname, |
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int bus, |
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uint16_t address, |
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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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_retries(0), |
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// private |
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_bus(bus), |
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_address(address), |
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_frequency(frequency), |
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_dev(nullptr) |
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{ |
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} |
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I2C::~I2C() |
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{ |
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if (_dev) |
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up_i2cuninitialize(_dev); |
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} |
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int |
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I2C::init() |
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{ |
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int ret = OK; |
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/* attach to the i2c bus */ |
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_dev = up_i2cinitialize(_bus); |
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if (_dev == nullptr) { |
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debug("failed to init I2C"); |
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ret = -ENOENT; |
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goto out; |
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} |
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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 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 world where we are |
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log("on I2C bus %d at 0x%02x", _bus, _address); |
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out: |
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return ret; |
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} |
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int |
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I2C::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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I2C::transfer(uint8_t *send, unsigned send_len, uint8_t *recv, unsigned recv_len) |
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{ |
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struct i2c_msg_s msgv[2]; |
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unsigned msgs; |
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int ret; |
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unsigned tries = 0; |
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do { |
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// debug("transfer out %p/%u in %p/%u", send, send_len, recv, recv_len); |
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msgs = 0; |
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if (send_len > 0) { |
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msgv[msgs].addr = _address; |
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msgv[msgs].flags = 0; |
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msgv[msgs].buffer = send; |
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msgv[msgs].length = send_len; |
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msgs++; |
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} |
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if (recv_len > 0) { |
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msgv[msgs].addr = _address; |
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msgv[msgs].flags = I2C_M_READ; |
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msgv[msgs].buffer = recv; |
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msgv[msgs].length = recv_len; |
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msgs++; |
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} |
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if (msgs == 0) |
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return -EINVAL; |
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/* |
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* I2C architecture means there is an unavoidable race here |
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* if there are any devices on the bus with a different frequency |
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* preference. Really, this is pointless. |
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*/ |
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I2C_SETFREQUENCY(_dev, _frequency); |
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ret = I2C_TRANSFER(_dev, &msgv[0], msgs); |
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if (ret == OK) |
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break; |
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// reset the I2C bus to unwedge on error |
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up_i2creset(_dev); |
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} while (tries++ < _retries); |
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return ret; |
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} |
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} // namespace device
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