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标题: I2C4 添加设备读写失败 [打印本页]

作者: xuwj2009 时间: 2017-2-25 11:42
标题: I2C4 添加设备读写失败
参考wiki 在I2C4 上添加了个设备，dts 配置如下，i2c_add_driver返回值也是0,；开机后，用i2cdetect -y 4，检测出0x36位置显示"UU"；
但是执行读写操作时，返回-6，（No such device or address ）；求大神
&i2c4 {
      status = "okay";
      dlpc34@36 {
            compatible = "dlpc34";
//gpio-sw = <&gpio7 GPIO_D3 GPIO_ACTIVE_LOW>;
            reg = <0x36>;
   };
};
代码：
static const struct i2c_device_id dlpc34_id[] = {
{ "dlpc34", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, dlpc34_id);

static const struct of_device_id dlpc34_of_match[] = {
{ .compatible = "dlpc34" },
{}
};

static struct i2c_driver dlpc34_driver = {
.driver = {
.name = "dlpc34",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(dlpc34_of_match),
},
.probe = dlpc34_probe,
.remove = dlpc34_remove,
.id_table = dlpc34_id,
};

module_i2c_driver(dlpc34_driver);

作者: xuwj2009 时间: 2017-2-25 11:48
另外，检测SCL SDA是有信号的，芯片资料，是低速设备，我scl_rate设置的50*1000；
I 2 C interface ports support 100-kHz baud rate. By definition, I 2 C transactions operate at the
speed of the slowest device on the bus, thus there is no requirement to match the speed grade of all devices in
the system.

作者: xuwj2009 时间: 2017-2-27 19:32
结贴，原因：芯片读操作和标准的有差异！文档没看仔细；按照标准linux读写出现错误！

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