Re: [PATCH v4 2/2] serial: 8250: add driver for KEBA UART

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Nov 26, 2025 at 10:06:17PM +0100, Gerhard Engleder wrote:
> On 26.11.25 14:17, Andy Shevchenko wrote:
> > On Thu, Oct 23, 2025 at 05:12:29PM +0200, Gerhard Engleder wrote:

...

> > > +#include <linux/auxiliary_bus.h>
> > 
> > + bits.h
> > + container_of.h
> > 
> > > +#include <linux/device.h>
> > 
> > I don't see how it's being used.
> > What I see are
> > 
> > + dev_printk.h
> > + device/devres.h
> > 
> > + err.h
> > 
> > > +#include <linux/io.h>
> > > +#include <linux/misc/keba.h>
> > 
> > + mod_devicetable.h
> > 
> > > +#include <linux/module.h>
> > 
> > + spinlock.h
> > + types.h
> 
> Is there any extra tool to check for missing headers? Or do I have to
> check the header for every used function?

There is iwyu, which is heavily tweaked by Jonathan Cameron for use in Linux
kernel and even though it gives some false positives.

I did this manually by reading the code of the driver and remembering which
header provides which API.

...

> > Can't you call uart_read_port_properties()?
> > 
> > If ever you gain some properties either via FW description or via software
> > nodes, they will be automatically used without need to update the driver!
> 
> Yes that would be some nice behavior. But __uart_read_properties()
> sets some defaults even if no firmware node exist (UPF_SHARE_IRQ,

Is it a problem? Even a single IRQ may be marked shared.

> 0 as irq number

It doesn't do that, it just skips setting it in that case.

> or it fails if not irq number is found).

Yeah, this is most "problematic" part in case of this driver. Why is it
auxiliary and not platform? With that the __uart_read_properties() needs
to be updated to also query IRQ from respective aux device, and aux dev
needs implementation of dev_is_auxiliary(). Not that big deal, though.

> So __uart_read_properties() would need to be changed. IMO it makes no sense
> to change __uart_read_properties() as this functionality is currently
> not required.

Yes, but as I said it will give you for free the possibility to use those
properties without future modifications of the driver. OTOH, driver is in
tree and modifications will be needed one way or another :-)

-- 
With Best Regards,
Andy Shevchenko