29 使用内核里的W25Q32设备驱动

W25Q32是一个spi接口的存放芯片, 容量32M比特(4M字节).
驱动文件在"drivers/mtd/devices/m25p80.c"

static struct spi_driver m25p80_driver = { 
    .driver = { 
        .name   = "m25p80",
        .of_match_table = m25p_of_table,
    },  
    .id_table   = m25p_ids, //使用id_table来匹配
    .probe  = m25p_probe,
    .remove = m25p_remove,
};

//支持的芯片型号
static const struct spi_device_id m25p_ids[] = {
 	  ...
    {"at25df321a"}, {"at25df641"},  {"at26df081a"},
    {"mx25l4005a"}, {"mx25l1606e"}, {"mx25l6405d"}, {"mx25l12805d"},
    {"mx25l25635e"},{"mx66l51235l"},
    {"n25q064"},    {"n25q128a11"}, {"n25q128a13"}, {"n25q512a"},
    {"s25fl256s1"}, {"s25fl512s"},  {"s25sl12801"}, {"s25fl008k"},
    {"s25fl064k"},
    {"sst25vf040b"},{"sst25vf016b"},{"sst25vf032b"},{"sst25wf040"},
    {"m25p40"}, {"m25p80"}, {"m25p16"}, {"m25p32"},
    {"m25p64"}, {"m25p128"},
    {"w25x80"}, {"w25x32"}, {"w25q32"}, {"w25q32dw"},
    {"w25q80bl"},   {"w25q128"},    {"w25q256"},
	...
}; 

w25q32接在spi0接口，在设备树文件里的描述:

&spi0 {
    status = "okay";

    spiflash {
        compatible = "w25q32"; //设备名就为"w25q32"与设备驱动里的id_table项匹配
        reg = <0>;
        status = "okay";
        spi-max-frequency = <10000000>;
        buswidth = <8>;
    };  
};

////////////////////////////////////////////////////////////////////////////////////////
因设备驱动提供的是mtd接口，所以设备驱动与设备匹配后会产生"mtd0 mtdblock0"等设备文件

mkfs.ext2 /dev/mtdblock0   //先格式化设备分区
mount /dev/mtdblock0 /mnt    //再挂载上来操作即可