/*
 * Copyright (C) 2023 Daniele Lacamera <root@danielinux.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include "adc.h"


/* ADC */

#define APB2_CLOCK_ER           (*(volatile uint32_t *)(0x40023844))
#define ADC3_APB2_CLOCK_ER_VAL 	(1 << 10)

#define ADC3_BASE       (0x40012200)
#define ADC_COM_BASE    (0x40012300)
#define ADC_COM_CCR     (*(volatile uint32_t *)(ADC_COM_BASE + 0x04))
#define ADC3_SR         (*(volatile uint32_t *)(ADC3_BASE + 0x00))
#define ADC3_CR1        (*(volatile uint32_t *)(ADC3_BASE + 0x04))
#define ADC3_CR2        (*(volatile uint32_t *)(ADC3_BASE + 0x08))
#define ADC3_SMPR1      (*(volatile uint32_t *)(ADC3_BASE + 0x0c))
#define ADC3_SMPR2      (*(volatile uint32_t *)(ADC3_BASE + 0x10))
#define ADC3_SQR3       (*(volatile uint32_t *)(ADC3_BASE + 0x34))
#define ADC3_DR         (*(volatile uint32_t *)(ADC3_BASE + 0x4c))
#define ADC_CR1_SCAN            (1 << 8)
#define ADC_CR2_EN              (1 << 0)
#define ADC_CR2_CONT            (1 << 1)
#define ADC_CR2_SWSTART         (1 << 30)
#define ADC_SR_EOC              (1 << 1)
#define ADC_SMPR_SMP_480CYC     (0x7)




// A0: ADC3_IN0
// F6: ADC3_IN4
// F8: ADC3_IN6
// F9: ADC3_IN7

int adc_init(void)
{
    int i;
    uint32_t val;
    /* Enable clock */
    APB2_CLOCK_ER |= ADC3_APB2_CLOCK_ER_VAL;

    /* Power off */
    ADC3_CR2 &= ~(ADC_CR2_EN);

    /* Set common clock prescaler */
    ADC_COM_CCR &= ~(0x03 << 16);

    /* Disable scan mode */
    ADC3_CR1 &= ~(ADC_CR1_SCAN);

    /* Set one-shot (disable continuous mode) */
    ADC3_CR2 &= ~(ADC_CR2_CONT);

    /* Set sample time for all channels */
    val = ADC3_SMPR1;

    for (i = 0; i < 10; i++) {
            val |= ADC_SMPR_SMP_480CYC << (i * 3);
    ADC3_SMPR1 = val;
    val = ADC3_SMPR2;
    for (i = 10; i < 18; i++) 
            val |= ADC_SMPR_SMP_480CYC << ((i-10) * 3);
    }
    ADC3_SMPR2 = val;
    ADC3_CR2 &= ~(ADC_CR2_EN);
    return 0;
}


void pot_read(uint32_t *potl, uint32_t *potr)
{
    if (potl) {
        ADC3_SQR3 |= (POTL_CHANNEL);
        ADC3_CR2 |= ADC_CR2_EN;
        ADC3_CR2 |= ADC_CR2_SWSTART;
        while (ADC3_CR2 & ADC_CR2_SWSTART);;
        while ((ADC3_SR & ADC_SR_EOC) == 0);;
        *potl = ADC3_DR;
        if (*potl < 15)
            *potl = 0;
        if (*potl > 4080)
            *potl = 4096;
        ADC3_SQR3 &= ~(POTL_CHANNEL);
    }
    if (potr) {
        ADC3_SQR3 |= (POTR_CHANNEL);
        ADC3_CR2 |= ADC_CR2_EN;
        ADC3_CR2 |= ADC_CR2_SWSTART;
        while (ADC3_CR2 & ADC_CR2_SWSTART);;
        while ((ADC3_SR & ADC_SR_EOC) == 0);;
        *potr = ADC3_DR;
        if (*potr < 15)
            *potr = 0;
        if (*potr > 4080)
            *potr = 4096;
        ADC3_SQR3 &= ~(POTR_CHANNEL);
    }
}

void joy_read(uint32_t *joy_x, uint32_t *joy_y)
{
    if (joy_x) {
        ADC3_SQR3 |= (JOYX_CHANNEL);
        ADC3_CR2 |= ADC_CR2_EN;
        ADC3_CR2 |= ADC_CR2_SWSTART;
        while (ADC3_CR2 & ADC_CR2_SWSTART);;
        while ((ADC3_SR & ADC_SR_EOC) == 0);;
        *joy_x = ADC3_DR;
        ADC3_SQR3 &= ~(JOYX_CHANNEL);
    }
    if (joy_y) {
        ADC3_SQR3 |= (JOYY_CHANNEL);
        ADC3_CR2 |= ADC_CR2_EN;
        ADC3_CR2 |= ADC_CR2_SWSTART;
        while (ADC3_CR2 & ADC_CR2_SWSTART);;
        while ((ADC3_SR & ADC_SR_EOC) == 0);;
        *joy_y = ADC3_DR;
        ADC3_SQR3 &= ~(JOYY_CHANNEL);
    }
}