/**
 * @file keypad.c
 * Manages the GPIO keypad using IO expanders
 *
 * Copyright (C) 2018 Clyne Sullivan
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <stm32l476xx.h>
#include <gpio.h>

#define ADDR 0x20

#define CONTROL 0x41
#define ADDRESS 0x12

void keypad_init(void)
{
	// clock init
	RCC->CCIPR &= ~(RCC_CCIPR_I2C1SEL_Msk);
	RCC->CCIPR |= 2 << RCC_CCIPR_I2C1SEL_Pos; 
	RCC->APB1ENR1 |= RCC_APB1ENR1_I2C1EN;

	// set times
	// PRESC, SCLDEL, SDADEL, SCLH, SCLL
	I2C1->TIMINGR = (0 << 28) | (2 << 20) | (0 << 16) | (2 << 8) | 4;

	// gpio init
	gpio_mode(GPIOB, 8, ALTERNATE);
	gpio_mode(GPIOB, 9, ALTERNATE);
	GPIOB->AFR[1] &= ~(0xFF);
	GPIOB->AFR[1] |= 0x44;

	// go go go
	I2C1->CR1 |= I2C_CR1_PE;

	I2C1->CR2 |= ADDR << 1;
	//I2C1->CR2 |= I2C_CR2_RD_WRN;
	I2C1->CR2 &= ~(I2C_CR2_NBYTES);
	I2C1->CR2 |= 1 << I2C_CR2_NBYTES_Pos;
	I2C1->CR2 |= I2C_CR2_RELOAD;
	I2C1->CR2 |= I2C_CR2_START;

	while (!(I2C1->ISR & I2C_ISR_TXE));

	I2C1->TXDR = ADDRESS;

	while (I2C1->ISR & I2C_ISR_BUSY);

	I2C1->ICR |= 0x30;
	I2C1->CR2 |= I2C_CR2_RD_WRN;
	I2C1->CR2 |= I2C_CR2_RELOAD;
	I2C1->CR2 |= I2C_CR2_START;
	
	while (1) {
		while (!(I2C1->ISR & I2C_ISR_RXNE));
		uint32_t v = I2C1->RXDR;
		(void)v;
	}
}