[PATCH 2/2] ehci-platform: Change compatible string from usb-ehci to ehci-platform

Hi,

On 02/11/2014 04:00 PM, Roger Quadros wrote:

Hi Hans,

On 02/11/2014 04:10 PM, Hans de Goede wrote:

quoted

The initial versions of the devicetree enablement patches for ehci-platform
used "ehci-platform" as compatible string. However this was disliked by various
reviewers because the platform bus is a Linux invention and devicetree is
supposed to be OS agnostic. After much discussion I gave up, added a:
"depends on !PPC_OF" to Kconfig to avoid a known conflict with PPC-OF platforms
and went with the generic usb-ehci as requested.

In retro-spect I should have stuck to my guns, because the dts files for many
existing boards already claim to be compatible with "usb-ehci", ie they have:

	compatible = "ti,ehci-omap", "usb-ehci";

In theory this should not be a problem since the "ti,ehci-omap" entry takes
presedence, but in practice using a conflicting compatible string is an issue,
because it makes which driver gets used depent on driver registration order.

This patch changes the compatible string claimed by ehci-platform (back) to
"ehci-platform", avoiding the driver registration / module loading ordering
problems, and removes the "depends on !PPC_OF" workaround.

Note that there already is a precedent for using ?hci-platform, in the form
of xhci-platform.c using "xhci-platfrom" as compatible string.

Signed-off-by: Hans de Goede <redacted>
---
 Documentation/devicetree/bindings/usb/usb-ehci.txt | 4 ++--
 drivers/usb/host/Kconfig                           | 1 -
 drivers/usb/host/ehci-platform.c                   | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
index 2c1aeeb..46f428a 100644
--- a/Documentation/devicetree/bindings/usb/usb-ehci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt

@@ -1,7 +1,7 @@
 USB EHCI controllers
 
 Required properties:
-  - compatible : should be "usb-ehci".
+  - compatible : should be "ehci-platform".

Won't this break DT binding info for power PC?

The powerpc bindings have never been really properly documented, ie
they rely on both usb-ehci and ibm,usb-ehci-440epx strings being there,
which was never documented. Given the issues surrounding using usb-ehci
as a compatible string I think completely removing it from the bindings
docs is best.

I'm even OK with removing "usb-ehci" and "usb-ohci" compatibles from all OMAP dts files
since they aren't really compatible with the original PPC driver.

I don't think that is necessary, as your grep has shown there are a lot
of dts files using compatible = "foo", "usb-?hci"; and some may even have
the dts in firmware, so we should simply make sure not to break such dts.

Regards,

Hans