mcp2515驱动的实现

1、在配置Linux 编译选项时，开启相应的SPI 选项，如下所示
    -> Device Drivers
      -> SPI support
       SPI support
          *** SPI Master Controller Drivers ***
      -*- Bitbanging SPI master
      <*> Samsung S3C24XX series SPI
      < > Samsung S3C24XX series SPI by GPIO
          *** SPI Protocol Masters ***
      < > SPI EEPROMs from most vendors
      <*> User mode SPI device driver support
      < > Infineon TLE62X0 (for power switching)
设置完成保存。
 
2.驱动文件mcp251x.c mcp251x.h can.h
文件mcp251x.c放在目录drivers/net/can/下；
文件mcp251x.h放在目录include/linux/can/platform/下；
文件can.h放在目录include/linux/can/下
 
3.添加配置文件drivers/net/can/Kconfig
在文件中添加
config CAN_MCP251X
       tristate "Microchip 251x series SPI CAN Controller"
       depends on CAN && SPI
       default N
       ---help---
         Say Y here if you want support for the Microchip 251x series of
         SPI based CAN controllers.
 
4.在drivers/net/can/Makefile文件中添加编译文件
obj-$(CONFIG_CAN_MCP251X)                 += mcp251x.o
  
5. 修改文件arch/arm/mach-s3c2410/mach-smdk2410.c中添加spi板级启动信息
#include
#include        //包含s3c2410_spi_info结构体
#include   //包含struct mcp251x_platform_data结构体

static struct mcp251x_platform_data mcp251x_info = {
        .f_osc = 16000000,
        //.oscillator_frequency = 19000000,
        //.board_specific_setup = myboard_mcp251x_initfunc,
        //.device_reset = myboard_mcp251x_reset,
        //.transceiver_enable = NULL,
};
static struct spi_board_info spi_board_info[] __initdata = {
[0]=
{
        .modalias       = "mcp251x", //这个名称一定要与mcp251x.c驱动中
//proc函数中的.name要一致
        .platform_data  = &mcp251x_info,  //上面的结构体
        .irq              = IRQ_EINT3,            中断端口号
        .max_speed_hz  = 8000000,            //spi最大的速度
        .bus_num        = 0,            //spi0，1中选择spi0口
        .chip_select      = 0,            //多个芯片选择
},
};
static struct s3c2410_spi_info s3c2410_spi0_platdata = {
        .pin_cs = S3C2410_GPG2,     //片选端口指定
        .num_cs = 1,                  //总共端口数
       // .bus_num = 0,
};
 
smdk2410_devices数组中添加
&s3c_device_spi0,
smdk2410_init函数中添加
s3c_device_spi0.dev.platform_data= &s3c2410_spi0_platdata;
spi_register_board_info(spi_board_info, ARRAY_SIZE(spi_board_info));
 
6.重新编译内核
启动信息中有如下内容,说明成功了：
 
7 执行命令cat /proc/devices
显示252 mcp251x
  添加设备文件 mknod /dev/mcp251x c 252 0
执行应用程序
./can_test
显示如下
基本完成，接下来是接上硬件调试了