title: Linux device driver for a RS232 device in embedded system
body: <p>I have recently started learning to write Linux device drivers for a specific project that I am working on. Previously most of the work I have done has been with devices running no OS so Linux drivers and development is somewhat new to me.
  For the project I am working on I have an embedded system running a Linux based operating system. I have an external device with is controlled via RS232 that I need to write a driver for. </p>
  
  <p>Questions:</p>
  
  <p>1) Is there a way to access serial ports from withing kernel space (and possibly use serial.h, serial_core.h, etc.), how is this usually done, any good examples?</p>
  
  <p>2) From what I found it seems like it would be much easier to access the serial ports in user space by just opening dev/ttyS* and writing to it. When writing a driver for a device like this (RS232 device) is it preferred to do it in user space or is there a way to write a kernel module? How does one decide to write a driver as a kernel module over user space or vise versa?</p>
  
  <p>Are drivers only for generic devices such as UART/serial and then above that is userspace or should this driver be written as a kernel module? I appreciate the help, I have been unable to find much information to answer my questions.</p>