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103 lines
3.1 KiB
103 lines
3.1 KiB
/**************************************************************************** |
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* |
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* Copyright (C) 2020 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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#include <board_config.h> |
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#include <drivers/drv_adc.h> |
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#include <px4_platform_common/log.h> |
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#include <fcntl.h> |
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#include <stdint.h> |
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#include <unistd.h> |
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#define ADC_SYSFS_PATH "/sys/kernel/rcio/adc" |
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#define ADC_MAX_CHAN 6 |
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int _channels_fd[ADC_MAX_CHAN]; |
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int px4_arch_adc_init(uint32_t base_address) |
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{ |
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for (int i = 0; i < ADC_MAX_CHAN; i++) { |
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_channels_fd[i] = -1; |
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} |
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return 0; |
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} |
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void px4_arch_adc_uninit(uint32_t base_address) |
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{ |
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for (int i = 0; i < ADC_MAX_CHAN; i++) { |
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::close(_channels_fd[i]); |
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_channels_fd[i] = -1; |
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} |
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} |
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uint32_t px4_arch_adc_sample(uint32_t base_address, unsigned channel) |
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{ |
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if (channel > ADC_MAX_CHAN) { |
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PX4_ERR("channel %d out of range: %d", channel, ADC_MAX_CHAN); |
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return UINT32_MAX; // error |
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} |
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// open channel if necessary |
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if (_channels_fd[channel] == -1) { |
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// ADC_SYSFS_PATH |
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char channel_path[strlen(ADC_SYSFS_PATH) + 5] {}; |
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if (sprintf(channel_path, "%s/ch%d", ADC_SYSFS_PATH, channel) == -1) { |
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PX4_ERR("adc channel: %d\n", channel); |
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return UINT32_MAX; // error |
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} |
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_channels_fd[channel] = ::open(channel_path, O_RDONLY); |
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} |
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char buffer[10] {}; |
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if (::pread(_channels_fd[channel], buffer, sizeof(buffer), 0) < 0) { |
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PX4_ERR("read channel %d failed", channel); |
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return UINT32_MAX; // error |
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} |
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return atoi(buffer); |
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} |
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float px4_arch_adc_reference_v() |
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{ |
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return BOARD_ADC_POS_REF_V; |
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} |
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uint32_t px4_arch_adc_dn_fullcount() |
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{ |
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return 1 << 12; // 12 bit ADC |
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}
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