What happens when writing to a device driver?
For example:
echo "some text" > /proc/device_driver
I'm guessing that echo has a write-call that somehow invokes the write-function in the driver. What are the "steps" from the echo-function to the drivers write function?
As explained in the The Linux Kernel Module Programming Guide (5.2. Read and Write a /proc File), the kernel calls a function associated with the driver during the driver's initialization to read the data from userspace into the kernel.
The echo program does not know anything special about the kernel; the kernel does all of the work.
Further reading:
