/*
* File : ls1c_spi.c
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Change Logs:
* Date Author Notes
* 2017-10-23 勤为本 first version
*/
// 硬件spi接口源文件
#include <string.h>
#include "ls1c_public.h"
#include "ls1c_regs.h"
#include "ls1c_clock.h"
#include "ls1c_spi.h"
/*
* 获取指定SPI模块的基地址
* @SPIx SPI模块的编号
*/
inline void *ls1c_spi_get_base(unsigned char SPIx)
{
void *base = NULL;
switch (SPIx)
{
case LS1C_SPI_0:
base = (void *)LS1C_SPI0_BASE;
break;
case LS1C_SPI_1:
base = (void *)LS1C_SPI1_BASE;
break;
default:
base = NULL;
break;
}
return base;
}
/*
* 打印指定SPI模块的所有寄存器的值
* @spi_base 基地址
*/
void ls1c_spi_print_all_regs_info(void *spi_base)
{
rt_kprintf("[%s] SPCR=0x%x, SPSR=0x%x, SPER=0x%x, SFC_PARAM=0x%x, SFC_SOFTCS=0x%x, SFC_TIMING=0x%x\r\n",
__FUNCTION__,
reg_read_8(spi_base + LS1C_SPI_SPCR_OFFSET),
reg_read_8(spi_base + LS1C_SPI_SPSR_OFFSET),
reg_read_8(spi_base + LS1C_SPI_SPER_OFFSET),
reg_read_8(spi_base + LS1C_SPI_SFC_PARAM_OFFSET),
reg_read_8(spi_base + LS1C_SPI_SFC_SOFTCS_OFFSET),
reg_read_8(spi_base + LS1C_SPI_SFC_TIMING_OFFSET));
return ;
}
/*
* 根据SPI时钟频率计算分频系数
* @max_speed_hz SPI最大通信速度
* @ret 分频系数
*/
unsigned int ls1c_spi_get_div(unsigned int max_speed_hz)
{
unsigned long clk = 0;
unsigned int div = 0;
unsigned int div_tmp = 0;
unsigned int bit = 0;
clk = clk_get_apb_rate();
div = DIV_ROUND_UP(clk, max_speed_hz);
if (div < 2)
div = 2;
if (div > 4096)
div = 4096;
bit = ls1c_fls(div) - 1;
switch (1 << bit)
{
case 16:
div_tmp = 2;
if (div > (1 << bit))
{
div_tmp++;
}
break;
case 32:
div_tmp = 3;
if (div > (1 << bit))
{
div_tmp += 2;
}
break;
case 8:
div_tmp = 4;
if (div > (1 << bit))
{
div_tmp -= 2;
}
break;
default:
div_tmp = bit - 1;
if (div > (1 << bit))
{
div_tmp++;
}
break;
}
/*
rt_kprintf("[%s] clk=%ld, max_speed_hz=%d, div_tmp=%d, bit=%d\r\n",
__FUNCTION__, clk, max_speed_hz, div_tmp, bit);
*/
return div_tmp;
}
/*
* 设置时钟
* @spi_base 基地址
* @max_hz 最大频率，单位hz
*/
void ls1c_spi_set_clock(void *spi_base, unsigned long max_hz)
{
unsigned int div = 0;
unsigned char val = 0;
// 获取分频系数
div = ls1c_spi_get_div(max_hz);
// 设置spr
val = reg_read_8(spi_base + LS1C_SPI_SPCR_OFFSET);
val &= (~LS1C_SPI_SPCR_SPR_MASK); // spr清零
val |= (div & LS1C_SPI_SPCR_SPR_MASK); // 设置新的spr
reg_write_8(val, spi_base + LS1C_SPI_SPCR_OFFSET);
// 设置spre
val = reg_read_8(spi_base + LS1C_SPI_SPER_OFFSET);
val &= (~LS1C_SPI_SPER_SPRE_MASK); // spre清零
val |= ((div >> 2) & LS1C_SPI_SPER_SPRE_MASK); // 设置新的spre
reg_write_8(val, spi_base + LS1C_SPI_SPER_OFFSET);
return ;
}
/*
* 设置通信模式(时钟极性和相位)
* @spi_base 基地址
* @cpol 时钟极性
* @cpha 时钟相位
*/
void ls1c_spi_set_mode(void *spi_base, unsigned char cpol, unsigned char cpha)
{
unsigned char val = 0;
val = reg_read_8(spi_base + LS1C_SPI_SPCR_OFFSET);
// 设置时钟极性--cpol
val &= (~LS1C_SPI_SPCR_CPOL_MASK); // cpol清0
val |= (cpol << LS1C_SPI_SPCR_CPOL_BIT); // 写入新的cpol
// 设置时钟相位--cpha
val &= (~LS1C_SPI_SPCR_CPHA_MASK); // cpha清0
val |= (cpha << LS1C_SPI_SPCR_CPHA_BIT); // 写入新的cpha
reg_write_8(val, spi_base + LS1C_SPI_SPCR_OFFSET);
return ;
}
/*
* 设置指定片选为指定状态
* @spi_base 基地址
* @cs 片选
* @new_status 片选引脚的新状态，取值为0或1，即高电平或低电平
*/
void ls1c_spi_set_cs(void *spi_base, unsigned char cs, int new_status)
{
unsigned char val = 0;
val = reg_read_8(spi_base + LS1C_SPI_SFC_SOFTCS_OFFSET);
val |= 0x01 << cs ; //对应的csen=1
if (new_status) // cs = 1
{
val |= (0x10 << cs); // 指定csn=1
}
else // cs = 0
{
val &= ~(0x10 << cs); // 指定csn=0
}
reg_write_8(val, spi_base + LS1C_SPI_SFC_SOFTCS_OFFSET);
return ;
}
/*
* 等待收发完成
* @spi_base 基地址
*/
inline void ls1c_spi_wait_txrx_done(void *spi_base)
{
int timeout = LS1C_SPI_TX_TIMEOUT;
while (timeout--)
{
if (LS1C_SPI_SPSR_SPIF_MASK & reg_read_8(spi_base + LS1C_SPI_SPSR_OFFSET))
break;
}
return ;
}
/*
* 清中断和标志位
* @spi_base 基地址
*/
inline void ls1c_spi_clear(void *spi_base)
{
unsigned char val = 0;
// 清中断
val = reg_read_8(spi_base + LS1C_SPI_SPSR_OFFSET);
val |= LS1C_SPI_SPSR_SPIF_MASK;
reg_write_8(val, spi_base + LS1C_SPI_SPSR_OFFSET);
// 清溢出标志位(Write-Collision Clear)
val = reg_read_8(spi_base + LS1C_SPI_SPSR_OFFSET);
if (LS1C_SPI_SPSR_WCOL_MASK & val)
{
rt_kprintf("[%s] clear register SPSR's wcol!\r\n",__FUNCTION__); // 手册和linux源码中不一样，加个打印看看
reg_write_8(val & ~LS1C_SPI_SPSR_WCOL_MASK, spi_base + LS1C_SPI_SPSR_OFFSET); // 写0，linux源码中是写0
// reg_write_8(val | LS1C_SPI_SPSR_WCOL_MASK, spi_base + LS1C_SPI_SPSR_OFFSET); // 写1，按照1c手册，应该写1
}
return ;
}
/*
* 通过指定SPI发送接收一个字节
* 注意，在多任务的系统中，此函数需要互斥。
* 即保证在和某个从设备收发某个字节的过程中，不能被切换到其它任务同时与另外的在同一个SPI总线上的从设备通信
* 因为龙芯1c的每路SPI上可能接有不同的从设备，通信频率、模式等可能不同
* @spi_base 基地址
* @tx_ch 待发送的数据
* @ret 收到的数据
*/
unsigned char ls1c_spi_txrx_byte(void *spi_base, unsigned char tx_ch)
{
unsigned char rx_ch = 0;
// 收发数据
reg_write_8(tx_ch, spi_base + LS1C_SPI_TxFIFO_OFFSET); // 开始发送
ls1c_spi_wait_txrx_done(spi_base); // 等待收发完成
rx_ch = reg_read_8(spi_base + LS1C_SPI_RxFIFO_OFFSET); // 读取收到的数据
ls1c_spi_clear(spi_base); // 清中断和标志位
return rx_ch;
}