概述

RT-Thread 對SPI總線的驅動，抽象出了spi bus 的設備驅動，我們基于S32K146 的硬件學習spi bus 設備驅動。

SPI總線驅動適配

驅動涉及的主要結構體為如下:

rt_spi_device:app 通過該結構體和bus 綁定通過bus 控制spi總線

rt_spi_bus spi bus總線設備抽象

rt_spi_ops bus設備依賴的底層操作函數

結構體關系如下：

對于總線設備的驅動對接我們需要實現對應的ops函數。

使用S32 Design Studio 工具配置spi1

本次實驗使用的是lpspi1 ,首先使用S32 Design Studio 工具生成pinmux 和 clk 初始化配置代碼。

配置SPI1 master 參數

配置pimmux

配置clk

適配SPI1 ops 函數至RT-Thread

根據上面的梳理，依賴芯片層實現ops函數并開啟spi設備驅動

config ops函數

tatic rt_err_t spi_configure(struct rt_spi_device* device,
struct rt_spi_configuration* configuration)
{
struct rt_spi_bus * spi_bus = (struct rt_spi_bus *)device->bus;
struct s32k_spi *spi_device = (struct s32k_spi *)spi_bus->parent.user_data;
status_t ret;


RT_ASSERT(device != RT_NULL);
RT_ASSERT(configuration != RT_NULL);


/* config spi init spi bus */
//LPSPI_DRV_MasterDeinit(spi_device->instance);


switch(configuration->mode & RT_SPI_MODE_3)
{
case RT_SPI_MODE_0:
spi_device->masterconfig->clkPhase = LPSPI_CLOCK_PHASE_2ND_EDGE;
spi_device->masterconfig->clkPolarity = LPSPI_SCK_ACTIVE_LOW;
break;
case RT_SPI_MODE_1:
spi_device->masterconfig->clkPhase = LPSPI_CLOCK_PHASE_1ST_EDGE;
spi_device->masterconfig->clkPolarity = LPSPI_SCK_ACTIVE_LOW;
break;
case RT_SPI_MODE_2:
spi_device->masterconfig->clkPhase = LPSPI_CLOCK_PHASE_2ND_EDGE;
spi_device->masterconfig->clkPolarity = LPSPI_SCK_ACTIVE_HIGH;
break;
case RT_SPI_MODE_3:
spi_device->masterconfig->clkPhase = LPSPI_CLOCK_PHASE_1ST_EDGE;
spi_device->masterconfig->clkPolarity = LPSPI_SCK_ACTIVE_HIGH;
break;
}


/* MSB or LSB */
if(configuration->mode & RT_SPI_MSB)
{
spi_device->masterconfig->lsbFirst = false;
}
else
{
spi_device->masterconfig->lsbFirst = true;
}


if(configuration->max_hz < 10000000)
spi_device->masterconfig->bitsPerSec = configuration->max_hz;


spi_device->masterconfig->bitcount = configuration->data_width;


ret = LPSPI_DRV_MasterInit(spi_device->instance,spi_device->status,spi_device->masterconfig);
RT_ASSERT(ret == STATUS_SUCCESS);


ret = LPSPI_DRV_MasterSetDelay(spi_device->instance, 1, 1, 1);
RT_ASSERT(ret == STATUS_SUCCESS);


return ret == STATUS_SUCCESS ? RT_EOK:RT_ERROR;

xfer ops 函數

truct s32k_spi
{
struct rt_spi_bus spi_bus; /* spi bus device */
lpspi_master_config_t * masterconfig; /* lpspi master config */
lpspi_state_t * status; /* lpspi driver status */
uint32_t instance; /* spi instance id */
char * bus_name;
}s32k_spi_t;


static rt_ssize_t spixfer(struct rt_spi_device* device, struct rt_spi_message* message){
struct rt_spi_bus * spi_bus = (struct rt_spi_bus *)device->bus;
struct s32k_spi *spi_device = (struct s32k_spi *)spi_bus->parent.user_data;
status_t ret;


RT_ASSERT(device != NULL);
RT_ASSERT(message != NULL);




ret = LPSPI_DRV_MasterTransferBlocking(spi_device->instance,message->send_buf,message->recv_buf,message->length,1000);
RT_ASSERT(ret == STATUS_SUCCESS);


return ret == STATUS_SUCCESS ? message->length:0;

添加如下初始化代碼像系統注冊spibus設備

xtern void LPSPI_DRV_IRQHandler(uint32_t instance);


void S32K14X_LPspi1_Master_Slave_IRQHandler(void){
/* enter interrupt */
rt_interrupt_enter();


LPSPI_DRV_IRQHandler(1);


/* leave interrupt */
rt_interrupt_leave();
}


/* private rt-thread spi ops function */
static struct rt_spi_ops s32k_spi_ops =
{
.configure = spi_configure,
.xfer = spixfer,
};


static struct s32k_spi spi1;




int rt_hw_spi_init(void){
int result = 0;


/* config spi strruct */
spi1.instance = INST_LPSPI_1;
spi1.masterconfig = &lpspi_1_MasterConfig0;
spi1.status = &lpspi_1State;
spi1.spi_bus.parent.user_data = (void *)&spi1;
spi1.bus_name = "spi1";


result = rt_spi_bus_register(&spi1.spi_bus, spi1.bus_name, &s32k_spi_ops);


RT_ASSERT(result == RT_EOK);


LOG_D("%s bus init done", spi1.bus_name);


if(result == RT_EOK)
{
INT_SYS_InstallHandler(LPSPI1_IRQn,S32K14X_LPspi1_Master_Slave_IRQHandler,NULL);
}




return result;
}


INIT_APP_EXPORT(rt_hw_spi_init);

驗證

添加如下測試代碼輸入 spi10 open/config/readid 命令打開并掛載到spi1總線，并讀取板子上的spi flash 的id信息

include
#include
#include
#include
#include


#define SPF_R_JEDEC_CMD (0x9Fu)
#define SPF_R_JEDEC_LEN (4u)


struct rt_spi_device spi1_device;


static void spi10(int argc,char *argv[]){
rt_err_t ret;
struct rt_spi_configuration cfg;
uint8_t sendbuff[4] = {SPF_R_JEDEC_CMD,0x00,0x00,0x00};
uint8_t recvbuff[4] = {0x00,0x00,0x00,0x00};


if(!strcmp(argv[1], "readid"))
{
rt_spi_transfer(&spi1_device,sendbuff,recvbuff,4);
rt_kprintf("read did [%x][%x][%x]\n",recvbuff[1],recvbuff[2],recvbuff[3]);
}
else if(!strcmp(argv[1], "open"))
{
ret = rt_spi_bus_attach_device(&spi1_device,"spi10","spi1",NULL);
if(ret != RT_EOK)
rt_kprintf("attach spi1 faied %d\n",ret);
}
else if(!strcmp(argv[1], "config"))
{
cfg.data_width = 8;
cfg.max_hz = 8000000;
cfg.mode = RT_SPI_MODE_3 | RT_SPI_MSB;
rt_spi_configure(&spi1_device,&cfg);
}
else if(!strcmp(argv[1], "read"))
{


}
}
MSH_CMD_EXPORT(spi10,spi10flashtest)

輸入命令驗證已經讀取到flash 的Id 信息說明SPI 總線和spi flash 通信ok ，而且系統內也已經多了spi1 bus設備和spi10 的spi 設備節點。

試驗讀取的did和芯片手冊的也是一致的。