Re: [PATCH 1/1] arm64: dts: lx2160a: Normalize the compatible string of "arm, sbsa-uart"

From: Shawn Guo <shawnguo@kernel.org>
To: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
Cc: Mark Kettenis <mark.kettenis@xs4all.nl>,
	leoyang.li@nxp.com, robh+dt@kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	Vabhav Sharma <vabhav.sharma@nxp.com>,
	Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH 1/1] arm64: dts: lx2160a: Normalize the compatible string of "arm, sbsa-uart"
Date: Sat, 12 Jun 2021 10:10:58 +0800	[thread overview]
Message-ID: <20210612021057.GE29138@dragon> (raw)
In-Reply-To: <52e44070-3b6f-b8ee-2f23-6059517755a8@huawei.com>

On Tue, May 25, 2021 at 10:00:30AM +0800, Leizhen (ThunderTown) wrote:
> 
> 
> On 2021/5/25 1:36, Mark Kettenis wrote:
> >> From: Zhen Lei <thunder.leizhen@huawei.com>
> >> Date: Mon, 24 May 2021 11:52:44 +0800
> >> Content-Type: text/plain; charset="us-ascii"
> >>
> >> The compatible string of ARM SBSA defined generic UART needs to contain
> >> only "arm,sbsa-uart" and does not need to contain "arm,pl011". Otherwise,
> >> the pl011.yaml will check it and falsely report many warnings similar to
> >> the following:
> >>
> >> arch/arm64/boot/dts/freescale/fsl-lx2160a-clearfog-cx.dt.yaml:
> >>  serial@21c0000: compatible:0: 'arm,pl011' was expected
> >>  serial@21c0000: compatible:1: 'arm,primecell' was expected
> >>
> >> Delete the redundant "arm,pl011" to fix it.
> > 
> > According to its reference manual, the LX2160A has a full PL011
> > implementation.  So I think this is the wrong "fix".
> 
> No, No, Please refer: https://www.spinics.net/lists/devicetree/msg424054.html
> 
> Now the "arm,sbsa-uart" driver is mixed with amba-pl011.c，It's impossible
> "arm,pl011" is loaded but "arm,sbsa-uart" is not loaded. So it makes no sense
> to append "arm, pl011" to the end of the compatible string as an alternative
> driver.
> 
> drivers/tty/serial/amba-pl011.c:2784:       { .compatible = "arm,sbsa-uart", },

I guess Mark is suggesting the following fix.

                uart0: serial@21c0000 {
-                       compatible = "arm,sbsa-uart","arm,pl011";
+                       compatible = "arm,pl011", "arm,primecell";
                        reg = <0x0 0x21c0000 0x0 0x1000>;
                        interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
-                       current-speed = <115200>;
                        status = "disabled";
                };

I copied some folks who might help clarify whether LX2160A UART is a SBSA
or a full PL011.

Shawn

> 
> 
> > 
> >> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> >> ---
> >>  arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi | 8 ++++----
> >>  1 file changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi b/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi
> >> index 4fcc869c21a4..417546616d85 100644
> >> --- a/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi
> >> +++ b/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi
> >> @@ -920,7 +920,7 @@
> >>  		};
> >>  
> >>  		uart0: serial@21c0000 {
> >> -			compatible = "arm,sbsa-uart","arm,pl011";
> >> +			compatible = "arm,sbsa-uart";
> >>  			reg = <0x0 0x21c0000 0x0 0x1000>;
> >>  			interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
> >>  			current-speed = <115200>;
> >> @@ -928,7 +928,7 @@
> >>  		};
> >>  
> >>  		uart1: serial@21d0000 {
> >> -			compatible = "arm,sbsa-uart","arm,pl011";
> >> +			compatible = "arm,sbsa-uart";
> >>  			reg = <0x0 0x21d0000 0x0 0x1000>;
> >>  			interrupts = <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>;
> >>  			current-speed = <115200>;
> >> @@ -936,7 +936,7 @@
> >>  		};
> >>  
> >>  		uart2: serial@21e0000 {
> >> -			compatible = "arm,sbsa-uart","arm,pl011";
> >> +			compatible = "arm,sbsa-uart";
> >>  			reg = <0x0 0x21e0000 0x0 0x1000>;
> >>  			interrupts = <GIC_SPI 72 IRQ_TYPE_LEVEL_HIGH>;
> >>  			current-speed = <115200>;
> >> @@ -944,7 +944,7 @@
> >>  		};
> >>  
> >>  		uart3: serial@21f0000 {
> >> -			compatible = "arm,sbsa-uart","arm,pl011";
> >> +			compatible = "arm,sbsa-uart";
> >>  			reg = <0x0 0x21f0000 0x0 0x1000>;
> >>  			interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>;
> >>  			current-speed = <115200>;
> >> -- 
> >> 2.21.1
> >>
> >>
> >>
> >> _______________________________________________
> >> linux-arm-kernel mailing list
> >> linux-arm-kernel@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >>
> > 
> > .
> > 
> 

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