Re: PATCH 0/4] usbd: typec: fusb302: Add support for specifying supported alternate-modes through devicetree/fwnodes

[Hans de Goede <hdegoede@redhat.com>]

Hi Prashant,

On 12/2/21 20:29, Prashant Malani wrote:
> Hi Hans,
> 
> Sorry for posting on an old thread, but I was wondering if there was
> still a plan to submit this? This is something we'd like to use on
> Chrome OS too.
> 
> It sounded like the primary discussion was whether to have an "altmodes"
> property encaspulating the various alt modes, but not sure what the
> final consensus on that was (sounded to me like your current
> implementation was fine for now, and ACPI use cases would be handled
> later?).

Support for this has already landed, but so far has only been tested
on a x86/ACPI device, where the firmware-nodes parsed by the new
typec_port_register_altmodes() helper are setup through software-nodes,
see:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7b458a4c5d7302947556e12c83cfe4da769665d0
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55d8b34772e0728a224198ba605eed8cfc570aa0
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3d28466e5f4f8

In theory this should be usable for devicetree as is. But that would
require documenting the current in kernel swnode bindings as
official devicetree bindings and getting that through the devicetree
bindings review process.

I have deliberately not done this because the devicetree maintainers
have asked for properties / swnode "bindings" used only inside
the kernel (1) to NOT be documented as official devicetree bindings,
they (the dt bindings maintainers) want to first see at least one
real devicetree users before adding things like this to the
official devicetree bindings docs.

Note if the way typec_port_register_altmodes() parses the fwnode
properties needs to change as result of the devicetree bindings review
process, please let me know, because then the swnode-s created in
drivers/platform/x86/intel/int33fe/intel_cht_int33fe_typec.c
need to change to match so as to not regress things on those devices.

Regards,

Hans


1) between different kernel parts, as platform_data equivalent really





 Tue, Jul 14, 2020 at 01:36:13PM +0200, Hans de Goede wrote:
>> Hi All,
>>
>> This is a replacement series for an earlier attempt by me for this
>> from quite a while ago:
>>
>> https://patchwork.kernel.org/patch/11199517/
>>
>> As discussed there, this series implements an altmodes devicetree-fwnode
>> under the usb-connector node which has 1 child-node per supported
>> altmode and in that child-node the svid and vdo for the supported
>> altmode are specified.
>>
>> Note this patch-set does not contain any devicetree users of the
>> new bindings. The new support/binding is used on X86 Cherry Trail
>> devices with a fusb302 Type-C controller (special variant of the
>> INT33FE device in ACPI). But this patch should also help getting
>> Display Port altmode to work with the mainline kernel on boards
>> like the Pine RockPro64 and Pinebook Pro, which is why I've added
>> Tobias Schramm to the Cc since he has done mainline devicetree
>> work for the Pinebook Pro in the past.
>>
>> The 1st patch adds the dt-bindings docs. I'm not sure if this one
>> should go upstream through the USB tree together with patches 2-3 or
>> if this should go upstream separately, Rob ?
>>
>> Patches 2-3 add support for the new binding to Type-C controller drivers
>> using the tcpm framework, such as the fusb302 driver.
>>
>> Patch 4 uses swnodes to add the altmode info on the earlier mentioned
>> X86 CHT devices, making DP-altmode work there for the first time.
>>
>> Regards,
>>
>> Hans
>>
>