linux内核GPIO模拟I2C实例

/**

* struct i2c_gpio_platform_data - Platform-dependent data for i2c-gpio

* @sda_pin: GPIO pin ID to use for SDA

* @scl_pin: GPIO pin ID to use for SCL

* @udelay: signal toggle delay. SCL frequency is (500 / udelay) kHz

* @timeout: clock stretching timeout in jiffies. If the slave keeps

* SCL low for longer than this, the transfer will time out.

* @sda_is_open_drain: SDA is configured as open drain, i.e. the pin

* isn''t actively driven high when setting the output value high.

* gpio_get_value() must return the actual pin state even if the

* pin is configured as an output.

* @scl_is_open_drain: SCL is set up as open drain. Same requirements

* as for sda_is_open_drain apply.

* @scl_is_output_only: SCL output drivers cannot be turned off.

*/

struct i2c_gpio_platform_data {

unsigned int sda_pin;

}