/**********************************************************************
*   Copyright: (C)2023 LingYun IoT System Studio
*      Author: GuoWenxue<guowenxue@gmail.com> QQ: 281143292
* Description: ISKBoard DS18B20 temperature sensor Hardware Abstract Layer driver
*
*   ChangeLog:
*        Version    Date       Author            Description
*        V1.0.0  2023.04.3    GuoWenxue      Release initial version
***********************************************************************/
#include "main.h"
#include "miscdev.h"

typedef struct w1_gpio_s
{
	GPIO_TypeDef        *group;
	uint16_t             pin;
} w1_gpio_t;

static w1_gpio_t   W1Dat =  /* IO pin connected to PA12 */
{
		.group = GPIOA,
		.pin   = GPIO_PIN_12,
};

#define W1DQ_Input()	   	\
{	\
		GPIO_InitTypeDef GPIO_InitStruct = {0}; \
		GPIO_InitStruct.Pin = W1Dat.pin; \
		GPIO_InitStruct.Mode = GPIO_MODE_INPUT; \
		GPIO_InitStruct.Pull = GPIO_PULLUP; \
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
		HAL_GPIO_Init(W1Dat.group, &GPIO_InitStruct); \
}

#define W1DQ_Output()	   	\
{	\
		GPIO_InitTypeDef GPIO_InitStruct = {0}; \
		GPIO_InitStruct.Pin = W1Dat.pin; \
		GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP; \
		GPIO_InitStruct.Pull = GPIO_NOPULL; \
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
		HAL_GPIO_Init(W1Dat.group, &GPIO_InitStruct); \
}

#define W1DQ_Write(x)	HAL_GPIO_WritePin(W1Dat.group, W1Dat.pin, \
						(x==1)?GPIO_PIN_SET:GPIO_PIN_RESET)

#define W1DQ_Read() 	HAL_GPIO_ReadPin(W1Dat.group,  W1Dat.pin)


/* Master issues reset pulse and DS18B20s respond with presence pulse */
uint8_t ds18b20_reset(void)
{
	uint8_t            rv = 0;
	uint8_t            retry;

	/* Setup W1 DQ pin as output and high level*/
	W1DQ_Output();
	W1DQ_Write(1);
	delay_us(2);

	/* Reset pulse by pulling the DQ pin low >=480us */
	W1DQ_Write(0);
	delay_us(480);

	/* Master releases bus to high. When DS18B20 detects this rising edge, it waits 15µs to 60µs */
	W1DQ_Write(1);
	delay_us(60);

	/* Then DS18B20 transmits a presence pulse by pulling the W1 bus low for 60µs to 240µs */
	while( W1DQ_Read() && retry <240)
	{
		retry++;
		delay_us(1);
	}

	if(retry >= 240)
		rv = 1;

	delay_us(240);

	/* Master Rx time must >= 480us */
	W1DQ_Output();
	W1DQ_Write(1);
	delay_us(240);

	return rv;
}

void ds18b20_write(uint8_t byte)
{
	uint8_t            i = 0;

	W1DQ_Output();

	for(i=0; i<8; i++)
	{
		/* Write 1: pull low <= 15us, Write 0: pull low 15~60us*/
		W1DQ_Write(0);
		delay_us(10);

		/* DS18B20 bit sent by LSB (lower bit first) */
		if( byte & 0x1 )
			W1DQ_Write(1);
		else
			W1DQ_Write(0);

		/* Write 1/0 slot both >= 60us, hold the level for 60us */
		delay_us(60);

		/* Release W1 bus to high */
		W1DQ_Write(1);
		delay_us(2);

		/* Prepare for next bit */
		byte >>= 1;
	}
}


uint8_t ds18b20_read(void)
{
	uint8_t            i = 0;
	uint8_t            byte = 0;

	for(i=0; i<8; i++)
	{
		/* Read time slot is initiated by master pulling the W1 bus
		 * low for minimum of 1µs and then releasing the bus */
		W1DQ_Output();
		W1DQ_Write(0);
		delay_us(2);
		W1DQ_Write(1);
		delay_us(2);

		/* After master initiates read time slot, DS18B20 will begin
		 * transmitting a 1 or 0 on bus */
		W1DQ_Input();

		/* DS18B20 bit sent by LSB (lower bit first) */
		if( W1DQ_Read() )
		{
			byte |= 1<<i;
		}

		/* Read slot for >= 60us */
		delay_us(60);

		/* Release W1 bus to high */
		W1DQ_Output();
		W1DQ_Write(1);
		delay_us(2);
	}

	return byte;
}

static inline int ds18b20_start_convert(void)
{
	/* Master issues reset pulse and DS18B20s respond with presence pulse */
	if( 0 != ds18b20_reset() )
		return -1;

	/* Master issues Skip ROM command */
	ds18b20_write(0xCC);

	/* Master issues Convert T command. */
	ds18b20_write(0x44);

	return 0;
}

static inline int ds18b20_start_read(uint8_t *buf, int bytes)
{
	/* Master issues reset pulse and DS18B20s respond with presence pulse */
	if( 0 != ds18b20_reset() )
		return -1;

	/* Master issues Skip ROM command */
	ds18b20_write(0xCC);

	/* Master issues Read Scratchpad command. */
	ds18b20_write(0xBE);

	buf[0] = ds18b20_read();   /* Temperature LSB */
	buf[1] = ds18b20_read();   /* Temperature MSB */

	/*Don't care followed 7 bytes data */

	return 0;
}

int ds18b20_sample(float *temperature)
{
	uint8_t               byte[2];
	uint8_t               sign;
	uint16_t              temp;
	static uint8_t        firstin = 1;

	if( !temperature )
		return -1;

	if( 0 != ds18b20_start_convert() )
		return -2;

	/* First sample need 750ms delay */
	if( firstin )
	{
		HAL_Delay(750);
		firstin = 0;
	}

	if( 0 != ds18b20_start_read(byte, 2) )
		return -3;

	/* Temperature byte[0] is LSB, byte[1] is MSB, total 16 bit:
	 * Byte[0]:  bit[3:0]: decimal bits,  bit[7:4]: integer bits
	 * bYTE[1]:  bit[2:0]: integer bits,  bit[7:3]: sign bits
	 */
    if( byte[1]> 0x7 ) /* bit[7:3] is 1 */
    {
    	temp = ~(byte[1]<<8|byte[0]) + 1;  //补码
    	sign=0; //温度为负
    }
    else
    {
    	sign=1;//温度为正
    	temp = byte[1]<<8 | byte[0];
    }

   /* byte[1]的低三位和byte[0]的高四位组成温度值的整数部分,
    * 而byte[0]的低四位为小数精度部分,且精度系数为0.0625 */
    *temperature = (temp>>4) + (temp&0xF)*0.0625 ;
    if( !sign )
    {
    	*temperature = -*temperature;
    }

	return 0;
}