Re: [PATCH v9 13/15] serial: 8250_dw: add Ambarella CV75 quirks

[Linus Walleij]

On Thu, Oct 1, 2026 at 2:52 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Oct 01, 2026 at 08:41:02PM +0800, Long Zhao via B4 Relay wrote:

> > From: Long Zhao <longzhao@xxxxxxxxxxxxx>
> >
> > The Ambarella CV75 UART is Ambarella IP, not a Synopsys DesignWare
> > licensed block. At the register level it is close enough to DW APB UART
> > that a full custom UART driver is unnecessary: reuse 8250_dw with a
> > small platform quirk.
> >
> > Quirks:
> > - keep IER ETOI (bit 5) set for RX timeout behaviour
> > - skip set_rate; baud clock is managed outside the UART block
> >
> > Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> > Signed-off-by: Long Zhao <longzhao@xxxxxxxxxxxxx>
> > ---
> >  drivers/tty/serial/8250/8250_dw.c | 32 ++++++++++++++++++++++++++++++++
> >  1 file changed, 32 insertions(+)
>
> When you submit lots of different subsystem patches all in one series,
> it's hard, if not impossible, for subsystem maintainers to take them :(

In my experience people do this in cases like this it is because they
essentially dump out their "bring-up" tree, the thing they have
booting on the hardware so they know the pieces work together.

Long: can you split it up in topic branches and work on e.g. the
serial driver on a separate branch?

A better way to test the whole set of patces is to just create a
mixdown branch where you merge all the topic branched into
one "test" branch, then you boot and test this before sending
out each branch separately.

Each topic branch can be versioned separately with b4.

Yours,
Linus Walleij