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

[Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>]

Hi Hans,

On 02/11/2014 04:10 PM, Hans de Goede wrote:
> 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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  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?

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.

cheers,
-roger

>    - reg : should contain at least address and length of the standard EHCI
>      register set for the device. Optional platform-dependent registers
>      (debug-port or other) can be also specified here, but only after
> @@ -27,7 +27,7 @@ Example (Sequoia 440EPx):
>  
>  Example (Allwinner sun4i A10 SoC):
>     ehci0: usb@01c14000 {
> -	   compatible = "allwinner,sun4i-a10-ehci", "usb-ehci";
> +	   compatible = "allwinner,sun4i-a10-ehci", "ehci-platform";
>  	   reg = <0x01c14000 0x100>;
>  	   interrupts = <39>;
>  	   clocks = <&ahb_gates 1>;
> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
> index e28cbe0..a9707da 100644
> --- a/drivers/usb/host/Kconfig
> +++ b/drivers/usb/host/Kconfig
> @@ -255,7 +255,6 @@ config USB_EHCI_ATH79
>  
>  config USB_EHCI_HCD_PLATFORM
>  	tristate "Generic EHCI driver for a platform device"
> -	depends on !PPC_OF
>  	default n
>  	---help---
>  	  Adds an EHCI host driver for a generic platform device, which
> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
> index 8fde649..4f4d78f 100644
> --- a/drivers/usb/host/ehci-platform.c
> +++ b/drivers/usb/host/ehci-platform.c
> @@ -333,7 +333,7 @@ static int ehci_platform_resume(struct device *dev)
>  static const struct of_device_id vt8500_ehci_ids[] = {
>  	{ .compatible = "via,vt8500-ehci", },
>  	{ .compatible = "wm,prizm-ehci", },
> -	{ .compatible = "usb-ehci", },
> +	{ .compatible = "ehci-platform", },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(of, vt8500_ehci_ids);
>