Re: [PATCH] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

From: Conor Dooley <conor@kernel.org>
To: Yixun Lan <dlan@gentoo.org>
Cc: Alex Elder <elder@riscstar.com>,
	gregkh@linuxfoundation.org, jirislaby@kernel.org,
	robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org,
	matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com,
	lkundrak@v3.sk, devicetree@vger.kernel.org,
	linux-serial@vger.kernel.org, spacemit@lists.linux.dev,
	linux-mediatek@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] dt-bindings: serial: 8250: allow "main" and "uart" as clock names
Date: Tue, 29 Jul 2025 18:54:07 +0100	[thread overview]
Message-ID: <20250729-reshuffle-contented-e6def76b540b@spud> (raw)
In-Reply-To: <20250728225319-GYA900803@gentoo>

[-- Attachment #1: Type: text/plain, Size: 2480 bytes --]

On Tue, Jul 29, 2025 at 06:53:19AM +0800, Yixun Lan wrote:
> Hi Alex,
> 
> On 17:00 Mon 28 Jul     , Alex Elder wrote:
> > There are two compatible strings defined in "8250.yaml" that require
> > two clocks to be specified, along with their names:
> >   - "spacemit,k1-uart", used in "spacemit/k1.dtsi"
> >   - "nxp,lpc1850-uart", used in "lpc/lpc18xx.dtsi"
> > 
> > When only one clock is used, the name is not required.  However there
> > are two places that do specify a name:
> >   - In "mediatek/mt7623.dtsi", the clock for the "mediatek,mtk-btif"
> >     compatible serial device is named "main"
> >   - In "qca/ar9132.dtsi", the clock for the "ns8250" compatible
> >     serial device is named "uart"
> > 
> > In commit d2db0d7815444 ("dt-bindings: serial: 8250: allow clock 'uartclk'
> > and 'reg' for nxp,lpc1850-uart"), Frank Li added the restriction that two
> > named clocks be used for the NXP platform mentioned above.  Extend that
> > so that the two named clocks used by the SpacemiT platform are similarly
> > restricted.
> > 
> > Add "main" and "uart" as allowed names when a single clock is specified.
> > 
> > Fixes: 2c0594f9f0629 ("dt-bindings: serial: 8250: support an optional second clock")
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202507160314.wrC51lXX-lkp@intel.com/
> > Signed-off-by: Alex Elder <elder@riscstar.com>
> > ---
> >  .../devicetree/bindings/serial/8250.yaml      | 19 ++++++++++++++-----
> >  1 file changed, 14 insertions(+), 5 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
> > index e46bee8d25bf0..cef52ebd8f7da 100644
> > --- a/Documentation/devicetree/bindings/serial/8250.yaml
> > +++ b/Documentation/devicetree/bindings/serial/8250.yaml
> > @@ -61,11 +61,17 @@ allOf:
> >              - const: uartclk
> >              - const: reg
> ..
> >      else:
> would it be better to drop this 'else', and moving following 'if' block
> to the same level with "nxp,lpc1850-uart"?
> 
> the reason here would avoid too many indentions if add more constraint in
> the future if other SoC uart need different clock-names..

I agree, it's more typical to do it that way I think to boot.

Also, why is there a k1/lpc conditional bit that is not part of the
allOf in addition to the bits in the allOf? Can that get merged with the
allOf please?

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]