Only 2chip select lines so max number ofdevices is very limited. Bus is faster andcan be driven over longer cable runsthan I2C. Programming more difficult.Device selection very limited unless youare willing to solder SMD. UART Welcome tothe 1970s! 通用异步串行口。按照标准波特率完成双向通讯,速...
pd= &default_i2c_data; npd= s3c_set_platdata(pd,sizeof(structs3c2410_platform_i2c), &s3c_device_i2c0); if(!npd->cfg_gpio) npd->cfg_gpio= s3c_i2c0_cfg_gpio; } 在板文件中把platform_device注册进内核: staticstructplatform_device*mini2440_devices[] __initdata = { …… &s3c_device_i2...
If set to NULL, the SMBus protocol is simulated using common I2C messages */ /* master_xfer should return the number of messages successfully processed, or a negative value on error */ int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num); int (*smbus_xfer) ...
using common I2C messages *//* master_xfer should return the number of messages successfully processed, or a negative value on error */int(*master_xfer)(struct i2c_adapter*adap,struct i2c_msg*msgs,int num);int(*smbus_xfer)(struct i2c_adapter*adap,u16 addr,unsigned short flags,char read...
If set to NULL, the SMBus protocol is simulated using common I2C messages */ /* master_xfer should return the number of messages successfully processed, or a negative value on error */ int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num); int (*smbus_xfer)...
* i2c_register_board_info - statically declare I2C devices *@busnum: identifies the bus to which these devices belong *@info: vector of i2c device descriptors *@len: how many descriptors in the vector; may be zero to reserve * the specified bus number. ...
示例代码 两个重要的数据结构 struct i2c_rdwr_ioctl_data结构体 /inclue/linux/i2c-dev.h /* This is the structure as used...; /* pointers to i2c_msgs */ __u32 nmsgs; /* number of i2c_msgs */ }; struct i2c_msg 结构体 include/linux...参考 i2c驱动之调用ioctl函数进行读写at24c08 ...
/*TrytosettheI2Cadapternumberfromdt*/ bus_nr=of_alias_get_id(np,"i2c"); /* *SwitchtonewinterfaceiftheSoCalsoofferstheoldone. *ThecontrolbitislocatedintheGRFregisterspace. */ if(i2c->soc_data->grf_offset>=0){ structregmap*grf;
1、检查 device 是否存在,i2c bus number 和 device address 是否正确。示例如下:i2c number 为 6,addr 为 0x28: 复制 [31.092951][xxx]i2ci2c-6:addr:0x28,ACKerror 1. 2、检查 device 是否已经上电使能,以及正确的 init。 3、检查 i2c speed 是否适配,speed 大于 device 支持的 max speed 也会造成 AC...
using common I2C messages*//*master_xfer should return the number of messages successfully processed, or a negative value on error*/int(*master_xfer)(structi2c_adapter *adap,structi2c_msg *msgs,intnum);int(*smbus_xfer) (structi2c_adapter *adap, u16 addr, ...