Re: [RFC PATCH] USB: host: ehci-atmel: Allow enabling HSIC on SAMA5D2

From: Greg Kroah-Hartman
Date: Tue Aug 24 2021 - 02:45:32 EST


On Tue, Aug 24, 2021 at 08:37:02AM +0200, Alexander Dahl wrote:
> Unlike other SoC series featuring the 'atmel,at91sam9g45-ehci' USB EHCI
> controller, which have embedded USB high-speed transceivers for each
> port, the third port on the SAMA5D2 series is HSIC only. That HSIC
> interface is not enabled after a power-on reset, but can be enabled by
> setting a flag in a vendor specific EHCI register.
>
> The register offsets added to the new header file were compared with
> those for the SAM9G45, SAM9X25, SAMA5D3, SAMA5D4, and SAM9X60 series and
> there are no differences in the offsets or contents of those registers.
> Which of those additional vendor specific registers are supported,
> differs by SoC family. So while the HSIC enable feature is currently
> only present for SAMA5D2, it probably does not hurt to set it on the
> other families, hence no additional check for SoC family here.
>
> Tested on a custom board featuring a SAMA5D27C-D5M SiP connected to an
> USB3503 hub with an upstream HSIC interface.
>
> Link: https://community.atmel.com/forum/sama5d2-using-hsic-under-linux
> Signed-off-by: Alexander Dahl <ada@xxxxxxxxxxx>
> ---
>
> Notes:
> - for introducing new dt binding, would be nice to convert old one
> first, probably needs split up and multiple iteration review?
> - name of that new dt property?
> - register definitions put to a separate file, like
> 'drivers/usb/host/ehci-fsl.h'
> - unsure where exactly in the probe process that register write should
> happen, datasheet gives no hint
> - should suspend/resume be considered?
>
> drivers/usb/host/ehci-atmel.c | 17 +++++++++++++++++
> drivers/usb/host/ehci-atmel.h | 19 +++++++++++++++++++

No need for a new .h file that is only used in a single .c file. Just
put those few lines in the .c file please.

thanks,

greg k-h