On Mon, Jan 20, 2014 at 10:04:15AM +0000, Russell King - ARM Linux wrote:

On Mon, Jan 20, 2014 at 02:32:35PM +0530, Tushar Behera wrote:

quoted

uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically happen
during device probe call.

In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with same default major/minor numbers are
included in the kernel.

A typical case is observed with amba-pl011 and samsung-uart drivers.

NAK.  There should not be any other driver using amba-pl011's device numbers.

I agree, but there is.  And because of that, moving the registration to
the probe call fixes the issue with building a kernel with all of the
drivers built into them, so I'm going to take both of these patches, as
it does solve that problem, while still allowing the device number
collision to happen.

thanks,

greg k-h