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

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Date:   Wed, 17 Apr 2019 12:15:18 +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 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.

Regards,

Hans