What is platform device driver?
Platform drivers are dedicated to devices not based on conventional buses. I2C devices or SPI devices are platform devices, but respectively rely on I2C or SPI buses not on the platform bus. Everything needs to be done manually with the platform driver.
How many types of registers are?
Explanation: There are 4 types of shift registers, viz., Serial-In/Serial-Out, Serial-In/Parallel-Out, Parallel-In/Serial-Out and Parallel-In/Parallel-Out. Explanation: The main difference between a register and a counter is that a register has no specific sequence of states except in certain specialised applications.
What does the platform driver do in Linux?
Platform Driver The platform driver implements a probe function that is called by the OS when this driver is inserted. Since the driver is supposed to be platform independent, it depends on the platform_data functions to set up the device and make it operational.
How is the device driver independent of the platform?
This way, the device driver can be made independent of the platform and hence can be used across multiple platforms. For example, the below example implements functions for power ON/OFF the device and for doing the device reset. This is done by calling platform_device_register () function with the device instance as shown below.
What happens if platform device is not found?
If the device is not found, the driver is simply ignored. Platform device driver works a bit differently than normal hot-pluggable device driver. Platform device is either directly mounted on the board or part of the SoC and hence can’t be physically removed.
How does Linux platform driver probe function work?
When the platform_driver_probe() function is called, the operating system scans through the list of available platform devices and checks if the driver.name matches with the device name. If yes, it calls the driver probe function with the platform data.