Thread (6 messages) 6 messages, 4 authors, 2016-11-27

[PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

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From: afaerber@suse.de (Andreas Färber)
Date: 2016-11-27 22:14:47
Also in: linux-devicetree, lkml

Am 27.11.2016 um 22:25 schrieb Uwe Kleine-K?nig:
On Sun, Nov 27, 2016 at 08:37:24PM +0100, Andreas F?rber wrote:
quoted
Specify the baudrate.

Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
Cc: Uwe Kleine-K?nig <redacted>
Signed-off-by: Andreas F?rber <afaerber@suse.de>
You said with plain &uart0 the kernel uses a wrong baud rate? That's
strange. For me it works and I think it's the intended behaviour to
dermine the baud rate setup by the bootloader and use this.
IIRC the 8250 driver defaults to 9600n8 if unspecified.

Kernel tested: 4.9.0-rc2-next-20161028-00010-g4fb44d9-dirty

Maybe you used some console= argument overriding it?
I'd prefer it this way over hard coding the baud rate.
quoted
 arch/arm/boot/dts/armada-385-turris-omnia.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/armada-385-turris-omnia.dts b/arch/arm/boot/dts/armada-385-turris-omnia.dts
index f53cb8b73610..2eff012287d4 100644
--- a/arch/arm/boot/dts/armada-385-turris-omnia.dts
+++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
@@ -52,7 +52,7 @@
 	compatible = "cznic,turris-omnia", "marvell,armada385", "marvell,armada380";
 
 	chosen {
-		stdout-path = &uart0;
+		stdout-path = "serial0:115200n8";
 	};
 
 	memory {
This has the downside to depend on the alias. Not sure this is
considered modern. An alternative would be:

	stdout-path = "/soc/internal-regs/serial at 12000:115200n8";
Please don't unroll the path I'm trying to abstract elsewhere.

Like I said, the "serialX:115200n8" syntax is what all other Armada 38x
boards use:

git grep stdout-path -- arch/arm/boot/dts/ | grep armada-38
arch/arm/boot/dts/armada-385-db-ap.dts:		stdout-path = "serial1:115200n8";
arch/arm/boot/dts/armada-385-linksys.dtsi:		stdout-path =
"serial0:115200n8";
arch/arm/boot/dts/armada-388-clearfog.dts:		stdout-path =
"serial0:115200n8";
arch/arm/boot/dts/armada-388-db.dts:		stdout-path = "serial0:115200n8";
arch/arm/boot/dts/armada-388-gp.dts:		stdout-path = "serial0:115200n8";
arch/arm/boot/dts/armada-388-rd.dts:		stdout-path = "serial0:115200n8";

The alias is needed to reliably determine the tty device number and is
set "globally" in armada-38x.dtsi, so why is it a problem to rely on?

Regards,
Andreas
(maybe there even exists syntactic sugar to express this using &uart0?)
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