Writing Simple Device Driver In Linux

i_love_linux · 08-30-2007, 12:48 AM

Hi,

I want to ask is suppose I have one device which operates on serial port. I want to read/ write into this device using linux. How should I start with it? And where can I see the data coming from this device? Like in windows you have hyperterminal to view data transaction from and in serial port of PC. As I am new to write device driver I have asked such a basic question. I think this would be a smiplest device driver to start with. Can anyone help me out with this please?

Mara · 08-30-2007, 03:13 PM

If you plan to write your own serial port driver, you will need to actually write the driver for your special needs. If you just need to use the port, you can stay in the user space. Of course, you can write it as driver, too. Your program will look differently as module an as user-space program.

To access serial port you can use a tool like minicom. The port is just a file, so you can read/write to it. Serial ports are /dev/ttyS0, /dev/ttyS1 and so on.

i_love_linux · 08-31-2007, 04:37 AM

Thanks Mara. One more thing that I want to ask is if I write a code for device driver and later on insert its module then do I need to recompile the kernel to use this device driver?

ravime · 08-31-2007, 11:23 AM

Quote:

Originally Posted by i_love_linux

Thanks Mara. One more thing that I want to ask is if I write a code for device driver and later on insert its module then do I need to recompile the kernel to use this device driver?

NO. Just insert and you can use that driver

i_love_linux · 09-04-2007, 12:23 AM

Quote:

Originally Posted by ravime

NO. Just insert and you can use that driver

Ok.. Thanks.

.. I am gonna try it today.

johnhamiltion · 09-04-2007, 09:25 AM

Quote:

Originally Posted by i_love_linux

Hi,

I want to ask is suppose I have one device which operates on serial port. I want to read/ write into this device using linux. How should I start with it? And where can I see the data coming from this device? Like in windows you have hyperterminal to view data transaction from and in serial port of PC. As I am new to write device driver I have asked such a basic question. I think this would be a smiplest device driver to start with. Can anyone help me out with this please?

I think that Greg Kroah-Hartman deals with this in his book

"Linux Device Drivers 3."

You can download it (as a single web-page) from

http://m.domaindlx.com/LinuxHelp/ldd3/about-ldd3.htm or

sundialsvcs · 09-04-2007, 07:16 PM

When a device attaches to a serial port, you should consider carefully how the intended clients will view the device ... and whether the purpose of the device is truly "generic" or "application specific."

If this device provides a generic service to the system, then you can build a kernel-level driver for it.

If, on the other hand, the device is application specific, maybe what you want is a simple library... a set of functions and procedures that can be called by the program, all in user-land.