rt-thread/bsp/ls1cdev/libraries/ls1c_i2c.c

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/*
* Copyright (c) 2006-2018, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2017-09-06 勤为本 first version
*/
// 封装硬件i2c接口
#include "ls1c_public.h"
#include "ls1c_regs.h"
#include "ls1c_clock.h"
#include "ls1c_i2c.h"
#include "ls1c_delay.h"
/*
* I2C各个寄存器相对基地址的偏移
* 发送数据寄存器和接收数据寄存器的偏移是相同的
* 命令寄存器和状态寄存器的偏移是相同的,不同的是命令寄存器只写,状态寄存器只读
*/
#define LS1C_I2C_PRER_LOW_OFFSET (0) // 分频锁存器低字节寄存器偏移
#define LS1C_I2C_PRER_HIGH_OFFSET (1) // 分频锁存器高字节寄存器偏移
#define LS1C_I2C_CONTROL_OFFSET (2) // 控制寄存器偏移
#define LS1C_I2C_DATA_OFFSET (3) // 发送数据寄存器和接收数据寄存器的偏移是相同的
#define LS1C_I2C_CMD_OFFSET (4) // 命令寄存器偏移,只写
#define LS1C_I2C_STATUS_OFFSET (4) // 状态寄存器偏移,只读
// 控制寄存器的位域
#define LS1C_I2C_CONTROL_EN (0x80) // i2c模块使能
#define LS1C_I2C_CONTROL_IEN (0x40) // 中断使能
// 命令寄存器的位域
#define LS1C_I2C_CMD_START (0x90) // 产生START信号
#define LS1C_I2C_CMD_STOP (0x40) // 产生STOP信号
#define LS1C_I2C_CMD_READ (0x20) // 产生读信号即产生ACK信号
#define LS1C_I2C_CMD_WRITE (0x10) // 产生写信号
#define LS1C_I2C_CMD_READ_ACK (0x20) // 产生ACK信号与读信号相同
#define LS1C_I2C_CMD_READ_NACK (0x28) // 产生NACK信号
#define LS1C_I2C_CMD_IACK (0x00) // 产生中断应答信号
// 状态寄存器的位域
#define LS1C_I2C_STATUS_IF (0x01) // 中断标志位
#define LS1C_I2C_STATUS_TIP (0x02) // 指示传输的过程。1正在传输0传输完成
#define LS1C_I2C_STATUS_ARBLOST (0x20) // I2C核失去I2C总线的控制权
#define LS1C_I2C_STATUS_BUSY (0x40) // I2C总线忙标志
#define LS1C_I2C_STATUS_NACK (0x80) // 应答位标志。1没收到应答位0收到应答位
/*
* 获取指定i2c模块的基地址
* @I2Cx I2C模块的编号
*/
void *i2c_get_base(ls1c_i2c_t I2Cx)
{
void *base = NULL;
switch (I2Cx)
{
case LS1C_I2C_0:
base = (void *)LS1C_I2C0_BASE;
break;
case LS1C_I2C_1:
base = (void *)LS1C_I2C1_BASE;
break;
case LS1C_I2C_2:
base = (void *)LS1C_I2C2_BASE;
break;
default:
base = NULL;
break;
}
return base;
}
/*
* 向命令寄存器写命令
* @i2c_info_p i2c模块信息
* @cmd 命令
*/
void i2c_cmd(ls1c_i2c_info_t *i2c_info_p, unsigned char cmd)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
reg_write_8(cmd, i2c_base + LS1C_I2C_CMD_OFFSET);
return ;
}
/*
* 执行START命令发送START信号
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_start(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_START);
return ;
}
/*
* 执行STOP命令发送STOP信号
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_stop(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_STOP);
return ;
}
/*
* 执行写命令
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_write(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_WRITE);
return ;
}
/*
* 执行读ack命令发送读ack信号
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_read_ack(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_ACK);
return ;
}
/*
* 执行读nack命令,发送读nack信号
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_read_nack(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_NACK);
return ;
}
/*
* 发送中断应答信号
* @i2c_info_p i2c模块信息
*/
void i2c_cmd_iack(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd(i2c_info_p, LS1C_I2C_CMD_IACK);
return ;
}
/*
* 获取状态寄存器的值
* @i2c_info_p i2c模块信息
* @ret 状态寄存器的值
*/
unsigned char i2c_get_status(ls1c_i2c_info_t *i2c_info_p)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
return reg_read_8(i2c_base + LS1C_I2C_STATUS_OFFSET);
}
/*
* Poll the i2c status register until the specified bit is set.
* Returns 0 if timed out (100 msec).
* @i2c_info_p i2c模块信息
* @bit 寄存器的某一位
* @ret true or false
*/
int i2c_poll_status(ls1c_i2c_info_t *i2c_info_p, unsigned long bit)
{
int loop_cntr = 20000;
do {
delay_us(1);
} while ((i2c_get_status(i2c_info_p) & bit) && (0 < --loop_cntr));
return (0 < loop_cntr);
}
/*
* 初始化指定i2c模块
* @i2c_info_p 某个i2c模块的信息
*/
void i2c_init(ls1c_i2c_info_t *i2c_info_p)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
unsigned long i2c_clock = i2c_info_p->clock;
unsigned char ctrl = reg_read_8(i2c_base + LS1C_I2C_CONTROL_OFFSET);
unsigned long prescale = 0;
/* make sure the device is disabled */
ctrl = ctrl & ~(LS1C_I2C_CONTROL_EN | LS1C_I2C_CONTROL_IEN);
reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET);
// 设置时钟
i2c_clock = MIN(i2c_clock, LS1C_I2C_CLOCK_MAX); // 限制在最大允许范围内
prescale = clk_get_apb_rate();
prescale = (prescale / (5 * i2c_clock)) - 1;
reg_write_8(prescale & 0xff, i2c_base + LS1C_I2C_PRER_LOW_OFFSET);
reg_write_8(prescale >> 8, i2c_base + LS1C_I2C_PRER_HIGH_OFFSET);
// 使能
i2c_cmd_iack(i2c_info_p);
ctrl = ctrl | LS1C_I2C_CONTROL_EN;
reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET);
return ;
}
/*
* (再发送一个字节数据之后)接收从机发送的ACK信号
* @i2c_info_p i2c模块信息
* @ret LS1C_I2C_ACK or LS1C_I2C_NACK
*/
ls1c_i2c_ack_t i2c_receive_ack(ls1c_i2c_info_t *i2c_info_p)
{
ls1c_i2c_ack_t ret = LS1C_I2C_NACK;
if (LS1C_I2C_STATUS_NACK & i2c_get_status(i2c_info_p))
{
ret = LS1C_I2C_NACK;
}
else
{
ret = LS1C_I2C_ACK;
}
return ret;
}
/*
* 接收数据
* @i2c_info_p i2c模块信息
* @buf 数据缓存
* @len 待接收数据的长度
*/
ls1c_i2c_ret_t i2c_receive_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *buf, int len)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
int i = 0;
for (i=0; i<len; i++)
{
// 开始接收
if (i != (len - 1))
i2c_cmd_read_ack(i2c_info_p);
else
i2c_cmd_read_nack(i2c_info_p);
// 等待,直到接收完成
if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
return LS1C_I2C_RET_TIMEOUT;
// 读取数据,并保存
*buf++ = reg_read_8(i2c_base + LS1C_I2C_DATA_OFFSET);
}
return LS1C_I2C_RET_OK;
}
/*
* 发送START信号和地址
* @i2c_info_p i2c模块信息
* @slave_addr 从机地址
* @direction 数据传输方向(读、写)
*/
ls1c_i2c_ret_t i2c_send_start_and_addr(ls1c_i2c_info_t *i2c_info_p,
unsigned char slave_addr,
ls1c_i2c_direction_t direction)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
unsigned char data = 0;
// 等待i2c总线空闲
if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_BUSY))
return LS1C_I2C_RET_TIMEOUT;
// 填充地址到数据寄存器
data = (slave_addr << 1) | ((LS1C_I2C_DIRECTION_READ == direction) ? 1 : 0);
reg_write_8(data , i2c_base + LS1C_I2C_DATA_OFFSET);
// 开始发送
i2c_cmd_start(i2c_info_p);
// 等待,直到发送完成
if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
return LS1C_I2C_RET_TIMEOUT;
return LS1C_I2C_RET_OK;
}
/*
* 发送数据
* @i2c_info_p i2c模块信息
* @data 待发送的数据
* @len 待发送数据的长度
*/
ls1c_i2c_ret_t i2c_send_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *data, int len)
{
void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
int i = 0;
for (i=0; i<len; i++)
{
// 将一个字节数据写入数据寄存器
reg_write_8(*data++, i2c_base + LS1C_I2C_DATA_OFFSET);
// 开始发送
reg_write_8(LS1C_I2C_CMD_WRITE, i2c_base + LS1C_I2C_CMD_OFFSET);
// 等待,直到发送完成
if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
return LS1C_I2C_RET_TIMEOUT;
// 读取应答信号
if (LS1C_I2C_ACK != i2c_receive_ack(i2c_info_p))
return len;
}
return LS1C_I2C_RET_OK;
}
/*
* 发送STOP信号
* @i2c_info_p i2c模块信息
*/
void i2c_send_stop(ls1c_i2c_info_t *i2c_info_p)
{
i2c_cmd_stop(i2c_info_p);
return ;
}