easiest way to deactivate a driver at boot time?

[Clemens Gruber]

On Thu, Dec 15, 2016 at 03:49:01AM -0800, Greg KH wrote:
> On Thu, Dec 15, 2016 at 04:56:18AM -0500, Robert P. J. Day wrote:
> > 
> >   (Q asked by a colleague, a wee bit vague on details so i'm hoping
> > i'm describing it correctly, seems like it should be easy to solve.)
> > 
> >   short form of question: what is the standard way of, at boot time,
> > passing the kernel information to specify that a built-in driver
> > should *not* be started?
> 
> Depends on the subsystem and driver, the only "standard way" is to just
> not build the driver into the kernel in the first place and use modules
> and load the module from userspace as-needed.
> 
> Or, use the device tree that is passed to the kernel by the bootloader
> to define the hardware and if the hardware isn't defined, then no driver
> will get bound to it.

What about "fixing up" the device tree in U-Boot with functions from
common/fdt_support.(c|h)

Maybe you could use fdt_del_node_and_alias to delete that drivers
device tree node if it is not needed?

Regards,
Clemens