/******************************************************************************
 * The MIT License
 *
 * Copyright (c) 2010 Bryan Newbold.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *****************************************************************************/

#include "libmaple.h"
#include "gpio.h"
#include "dac.h"

/**
 * @brief DAC peripheral routines.
 */

dac_dev dac = {
    .regs = DAC_BASE,
};
const dac_dev *DAC = &dac;

/**
 * @brief Initialize the digital to analog converter
 * @param flags Flags:
 *      DAC_CH1: Enable channel 1
 *      DAC_CH2: Enable channel 2
 * @sideeffect May set PA4 or PA5 to INPUT_ANALOG
 */
void dac_init(uint32 flags) {
    /* First turn on the clock */
    rcc_clk_enable(RCC_DAC);
    rcc_reset_dev(RCC_DAC);

    if (flags & DAC_CH1) {
        dac_enable_channel(1);
    }

    if (flags & DAC_CH2) {
        dac_enable_channel(2);
    }
}

/**
 * @brief Write a 12-bit value to the DAC to output
 * @param channel channel to select (1 or 2)
 * @param val value to write
 */
void dac_write_channel(uint8 channel, uint16 val) {
    switch(channel) {
    case 1:
        DAC->regs->DHR12R1 = DAC_DHR12R1_DACC1DHR & val;
        break;
    case 2:
        DAC->regs->DHR12R2 = DAC_DHR12R2_DACC2DHR & val;
        break;
    }
}

/**
 * @brief Enable a DAC channel
 * @param channel channel to enable, either 1 or 2
 * @sideeffect May change pin mode of PA4 or PA5
 */
void dac_enable_channel(uint8 channel) {
    /*
     * Setup ANALOG mode on PA4 and PA5. This mapping is consistent across
     * all STM32 chips with a DAC. See RM0008 12.2.
     */
    switch (channel) {
    case 1:
        gpio_set_mode(GPIOA, 4, GPIO_INPUT_ANALOG);
        DAC->regs->CR |= DAC_CR_EN1;
        break;
    case 2:
        gpio_set_mode(GPIOA, 5, GPIO_INPUT_ANALOG);
        DAC->regs->CR |= DAC_CR_EN2;
        break;
    }
}

/**
 * @brief Disable a DAC channel
 * @param channel channel to disable, either 1 or 2
 */
void dac_disable_channel(uint8 channel) {
    switch (channel) {
    case 1:
        DAC->regs->CR &= ~DAC_CR_EN1;
        break;
    case 2:
        DAC->regs->CR &= ~DAC_CR_EN2;
        break;
    }
}