Re: [PATCH] powerpc/kmcent2: update the ethernet devices' phy properties
From: Scott Wood <oss@buserror.net>
Date: 2019-08-28 04:21:24
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linuxppc-dev
On Thu, 2019-08-08 at 23:09 +0200, Valentin Longchamp wrote:
Le mar. 30 juil. 2019 à 11:44, Madalin-cristian Bucur [off-list ref] a écrit :quoted
quoted
-----Original Message-----quoted
Le dim. 14 juil. 2019 à 22:05, Valentin Longchamp [off-list ref] a écrit :quoted
Change all phy-connection-type properties to phy-mode that are better supported by the fman driver. Use the more readable fixed-link node for the 2 sgmii links. Change the RGMII link to rgmii-id as the clock delays are added by the phy. Signed-off-by: Valentin Longchamp <redacted>I don't see any other uses of phy-mode in arch/powerpc/boot/dts/fsl, and I see lots of phy-connection-type with fman. Madalin, does this patch look OK? -ScottHi, we are using "phy-connection-type" not "phy-mode" for the NXP (former Freescale) DPAA platforms. While the two seem to be interchangeable ("phy-mode" seems to be more recent, looking at the device tree bindings), the driver code in Linux seems to use one or the other, not both so one should stick with the variant the driver is using. To make things more complex, there may be dependencies in bootloaders, I see code in u-boot using only "phy-connection-type" or only "phy-mode". I'd leave "phy-connection-type" as is.So I have finally had time to have a look and now I understand what happens. You are right, there are bootloader dependencies: u-boot calls fdt_fixup_phy_connection() that somehow in our case adds (or changes if already in the device tree) the phy-connection-type property to a wrong value ! By having a phy-mode in the device tree, that is not changed by u-boot and by chance picked up by the kernel fman driver (of_get_phy_mode() ) over phy-connection-mode, the below patch fixes it for us. I agree with you, it's not correct to have both phy-connection-type and phy-mode. Ideally, u-boot on the board should be reworked so that it does not perform the above wrong fixup. However, in an "unfixed" .dtb (I have disabled fdt_fixup_phy_connection), the device tree in the end only has either phy-connection-type or phy-mode, according to what was chosen in the .dts file. And the fman driver works well with both (thanks to the call to of_get_phy_mode() ). I would therefore argue that even if all other DPAA platforms use phy-connection-type, phy-mode is valid as well. (Furthermore we already have hundreds of such boards in the field and we don't really support "remote" u-boot update, so the u-boot fix is going to be difficult for us to pull). Valentin
Madalin, are you OK with the patch given this explanation? -Scott