Date:   Wed, 15 Mar 2023 11:09:53 +0200
From:   Heikki Krogerus <heikki.krogerus@linux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     "Ye, Xiang" <xiang.ye@intel.com>, Lee Jones <lee@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Matthias Kaehlcke <mka@chromium.org>,
        Wolfram Sang <wsa@kernel.org>,
        Tyrone Ting <kfting@nuvoton.com>,
        Mark Brown <broonie@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>, linux-usb@vger.kernel.org,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-spi@vger.kernel.org, linux-gpio@vger.kernel.org,
        srinivas.pandruvada@intel.com, sakari.ailus@linux.intel.com,
        zhifeng.wang@intel.com, wentong.wu@intel.com, lixu.zhang@intel.com
Subject: Re: [PATCH v5 1/5] usb: Add support for Intel LJCA device
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On Tue, Mar 14, 2023 at 05:52:52PM +0200, Andy Shevchenko wrote:
> On Tue, Mar 14, 2023 at 11:38:14PM +0800, Ye, Xiang wrote:
> > On Tue, Mar 14, 2023 at 10:36:57AM +0200, Heikki Krogerus wrote:
> > > On Tue, Mar 14, 2023 at 04:03:26PM +0800, Ye, Xiang wrote:
> 
> ...
> 
> > > You don't really seem to get any benefit from MFD. Perhaps it would be
> > > more appropriate and clear if you just registered auxiliary devices in
> > > this driver. Check drivers/base/auxiliary.c.
> > Yes, it should be a work. I have a question.
> > MFD provides the ACPI binding for sub-devices through
> > struct mfd_cell_acpi_match. But I didn't see this in drivers/base/auxiliary.c.
> > If using auxiliary bus to implement the LJCA sub-devices, we need to do
> > the sub-devices acpi binding manually in ljca.c.
> > 
> > Something Like:
> > adr = LJCA_ACPI_MATCH_GPIO
> > adev = acpi_find_child_device(parent, adr, false);
> > ACPI_COMPANION_SET(&pdev->dev, adev ?: parent);
> > 
> > Is that acceptable?

Looks ok to me.

> Maybe you can implement this on the level of auxiliary bus.

I would actually prefer that the auxiliary bus itself does not make
any assumptions regarding the whereabouts of the fwnodes at this
stage. Maybe later, when(if) there are more users.

thanks,

-- 
heikki