/*-
 * Copyright 2021 John-Mark Gurney.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <string.h>

#include <misc.h>

#include <sysinit.h>

#include <main.h>

static void
c13led(void)
{
	GPIO_InitTypeDef GPIO_InitStruct;

	__HAL_RCC_GPIOA_CLK_ENABLE();
	__HAL_RCC_GPIOB_CLK_ENABLE();
	__HAL_RCC_GPIOC_CLK_ENABLE();

	GPIO_InitStruct = (GPIO_InitTypeDef){
		.Pin = GPIO_PIN_3,
		.Mode = GPIO_MODE_OUTPUT_PP,
		.Pull = GPIO_NOPULL,
		.Speed = GPIO_SPEED_FREQ_LOW,
	};
	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

	GPIO_InitStruct = (GPIO_InitTypeDef){
		.Pin = GPIO_PIN_13,
		.Mode = GPIO_MODE_OUTPUT_PP,
		.Pull = GPIO_NOPULL,
		.Speed = GPIO_SPEED_FREQ_LOW,
	};
	HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

	HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_RESET);
}
SYSINIT_VF(c13led, SI_SUB_HAL, SI_ORDER_SECOND, c13led);

static TIM_HandleTypeDef htim2;

/* 36.2.2 Step 1 */
void
HAL_TIM_PWM_MspInit(TIM_HandleTypeDef *htim)
{
}

#define	PERIOD_VALUE	(700 - 1)

void
tim2ch4(void)
{
	GPIO_InitTypeDef GPIO_InitStruct;
	uint32_t uhPrescalerValue;

	/*
	 * various parts from F1's
	 * Projects/STM3210E_EVAL/Examples/TIM/TIM_PWMOutput/Src/main.c
	 */
	uhPrescalerValue = (uint32_t)(SystemCoreClock / 2000000) - 1;

	/* 36.2.2 Step 2a */
	__HAL_RCC_TIM2_CLK_ENABLE();

	/* 36.2.2 Step 2b */
	__HAL_RCC_GPIOA_CLK_ENABLE();

	GPIO_InitStruct = (GPIO_InitTypeDef){
		.Pin = GPIO_PIN_3,
		.Mode = GPIO_MODE_AF_PP,
		.Pull = GPIO_NOPULL,
		.Speed = GPIO_SPEED_FREQ_LOW,
	};
	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

	/* 36.2.2 Step 4 */
	htim2 = (TIM_HandleTypeDef){
		.Instance = TIM2,

		/* TIM_Base_InitTypeDef */
		.Init.Prescaler = uhPrescalerValue,
		.Init.Period = PERIOD_VALUE,
		.Init.CounterMode = TIM_COUNTERMODE_UP,
		.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE,
	};
	HAL_TIM_PWM_Init(&htim2);

}
SYSINIT_VF(tim2ch4, SI_SUB_HAL, SI_ORDER_THIRD, tim2ch4);

int
main(void)
{

	debug_printf("starting...\n");

#if 0
	/* toggle on LED */
	for (;;) {
		HAL_GPIO_WritePin(GPIOA, GPIO_PIN_3, GPIO_PIN_RESET);
		HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_RESET);
		HAL_Delay(250);
		HAL_GPIO_WritePin(GPIOA, GPIO_PIN_3, GPIO_PIN_SET);
		HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_SET);
		HAL_Delay(250);
	}
#else
	/* PA3 TIM2_CH4 */
	TIM_OC_InitTypeDef oconfig;
	oconfig = (TIM_OC_InitTypeDef){
		.OCMode		= TIM_OCMODE_PWM1,
		.OCPolarity	= TIM_OCPOLARITY_HIGH,
		.OCFastMode	= TIM_OCFAST_DISABLE,
		.OCNPolarity	= TIM_OCNPOLARITY_HIGH,
		.OCNIdleState	= TIM_OCNIDLESTATE_RESET,

		.OCIdleState	= TIM_OCIDLESTATE_RESET,

		.Pulse		= PERIOD_VALUE,	// OFF
	};
	HAL_TIM_PWM_ConfigChannel(&htim2, &oconfig, TIM_CHANNEL_4);
	HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_4);
	for (int i = 0;; i = (i + 1) % 3) {
		switch (i) {
		case 0:
			TIM2->CCR4 = PERIOD_VALUE;
			break;
		case 1:
			TIM2->CCR4 = PERIOD_VALUE / 2;
			break;
		case 2:
			TIM2->CCR4 = 0;
			break;
		}
#if 0
		HAL_Delay(100);
#else
		HAL_Delay(35);
#endif
	}
	HAL_TIM_PWM_Stop(&htim2, TIM_CHANNEL_4);
#endif
}