linux-kernel - Re: [PATCH v3 13/13] platform/x86: intel_cht_int33fe: Replacing the old connections with references

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Message-ID: <cb7cf930-cf76-ef73-49de-222895b133ea@redhat.com>
Date:   Wed, 17 Apr 2019 18:03:03 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v3 13/13] platform/x86: intel_cht_int33fe: Replacing the
 old connections with references

Hi,

On 17-04-19 12:44, Heikki Krogerus wrote:
> On Wed, Apr 17, 2019 at 12:15:18PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 17-04-19 11:32, Heikki Krogerus wrote:
>>> On Wed, Apr 17, 2019 at 11:19:28AM +0200, Hans de Goede wrote:
>>
>> <snip>
>>
>>>> That is not going to work since the (virtual) mux / orientation-switch
>>>> devices are only registered once the driver binds to the piusb30532 i2c
>>>> device, so when creating the nodes we only have the piusb30532 i2c device.
>>>
>>> It's not a problem, that's why we have the software nodes. The nodes
>>> can be created before the device entires. The node for pi3usb30532
>>> will just be the parent node for the new nodes we add for the mux and
>>> switch.
>>>
>>>> I've been thinking some more about this and an easy fix is to have separate
>>>> fwnode_match functions for typec_switch_match and typec_mux_match and have
>>>> them check that the dev_name ends in "-mux" resp. "-switch" that requires
>>>> only a very minimal change to "usb: typec: Registering real device entries for the muxes"
>>>> and then everything should be fine.
>>>
>>> I don't want to do anymore device name matching unless we have to, and
>>> here we don't have to. We can name the nodes for those virtual mux and
>>> switch, and then just do fwnode_find_named_child_node() in
>>> pi3usb30532.c for both of them.
>>
>> Thinking more about this, I have a feeling that this makes things needlessly
>> complicated, checking the dev_name *ends* in "-mux" resp. "-switch" should be
>> 100% reliable since we call:
>>
>>          dev_set_name(&sw->dev, "%s-switch", dev_name(parent));
>>          dev_set_name(&mux->dev, "%s-mux", dev_name(parent));
>>
>> When registering the switch / mux, so I believe doing name (suffix) comparison
>> here is fine and much simpler. Anyways this is just my 2 cents on this, I'm
>> happy with either solution, your choice.
> 
> You do have a point. I'll take a look how the two options look like,
> but maybe your way is better after all.

I whipped up a quick fix using my approach so that I can start working
on debugging the usb_role_switch_get call in tcpm.c returning NULL.

I've attached it, feel free to use this for v4 of the series if you
decide to go with this approach.

Regards,

Hans


> 
> thanks,
> 

View attachment "0001-FIXUP-usb-typec-Registering-real-device-entries-for-.patch" of type "text/x-patch" (2524 bytes)