drivers

It's very entertaining to hear people talking about Linux device drivers for particular platform. For example, "we have developed drivers for our chip for omap3evm". Or "our driver perfectly works on Mainstone therefore porting it to your PXA platfrom should be realy easy". And the best one "How much time would it take to make the driver we used with PXA270 work on PXA300?".
I admit I was not there in the VxWorks days. More than that, I almost was not there in 2.4 and early 2.6 kernel days. But making such statements now when driver model exists in Linux kernel for several years sounds real nonsense. In Linux either you have a device driver or not. It cannot be a driver that works on platform A and fails on platform B. If an SPI network chip has driver for a single development platform, or even worse, lot of

#ifdef PLATFORM_A
  ... some code ...
#elif defined(PLATFORM_B)
  ... some other code ...
#endif

fragments in the driver, it means that this chip has no Linux device driver.