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98 lines
2.2 KiB
C
98 lines
2.2 KiB
C
/*
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* Copyright (C) 2023 Mesotic SAS
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_rpx0xx
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* @ingroup drivers_periph_adc
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* @{
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*
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* @file
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* @brief Low-level ADC driver implementation
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*
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* @author Dylan Laduranty <dylan.laduranty@mesotic.com>
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* @}
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*/
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#include <errno.h>
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#include "cpu.h"
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#include "mutex.h"
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#include "periph/adc.h"
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#include "periph_conf.h"
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/**
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* @brief Lock to prevent concurrency issues when used from different threads
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*/
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static mutex_t lock;
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static inline void _prep(void)
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{
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mutex_lock(&lock);
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}
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static inline void _done(void)
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{
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mutex_unlock(&lock);
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}
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static void _disable_digital_func(gpio_t pin)
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{
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const gpio_pad_ctrl_t disable_digital_pad = {
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.input_enable = 0,
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.output_disable = 1,
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};
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gpio_set_pad_config(pin, disable_digital_pad);
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}
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int adc_init(adc_t line)
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{
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if (line >= ADC_NUMOF) {
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return -ENODEV;
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}
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/* Lock mutex for exclusive access */
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_prep();
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/* Reset ADC peripheral */
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periph_reset(RESETS_RESET_adc_Msk);
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periph_reset_done(RESETS_RESET_adc_Msk);
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/* Enable ADC peripheral and its clock */
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io_reg_atomic_set(&ADC->CS, 1 << ADC_CS_EN_Pos);
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/* Disable associated GPIO functionality as requested by datasheet */
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_disable_digital_func(adc_config[line].pin);
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/* Unlock mutex */
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_done();
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return 0;
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}
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int32_t adc_sample(adc_t line, adc_res_t res)
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{
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int val = 0;
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/* rpx0xx MCU only supports 12 bits resolution */
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if (res != ADC_RES_12BIT) {
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return -EINVAL;
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}
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/* Lock mutex for exclusive access */
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_prep();
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/* Select the channel */
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io_reg_write_dont_corrupt(&ADC->CS, adc_config[line].chan << ADC_CS_AINSEL_Pos,
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ADC_CS_AINSEL_Msk);
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/* Wait for ADC to be ready */
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while (!(ADC->CS & ADC_CS_READY_Msk)) {}
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/* Trigger one-shot sample */
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io_reg_atomic_set(&ADC->CS, 1 << ADC_CS_START_ONCE_Pos);
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/* Wait for completion */
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while (!(ADC->CS & ADC_CS_READY_Msk)) {}
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/* Get the result */
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val = ADC->RESULT & ADC_RESULT_RESULT_Msk;
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/* Unlock mutex */
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_done();
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return val;
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}
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