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 <20230309071100.2856899-2-xiang.ye@intel.com>
Date:   Thu, 09 Mar 2023 08:56:05 +0100
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Ye Xiang" <xiang.ye@intel.com>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Matthias Kaehlcke" <mka@chromium.org>,
        "Lee Jones" <lee@kernel.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,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>
Cc:     srinivas.pandruvada@intel.com, heikki.krogerus@linux.intel.com,
        "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
        "Sakari Ailus" <sakari.ailus@linux.intel.com>,
        zhifeng.wang@intel.com, wentong.wu@intel.com, lixu.zhang@intel.com
Subject: Re: [PATCH v4 1/5] mfd: Add support for Intel LJCA device
Content-Type: text/plain
Precedence: bulk

On Thu, Mar 9, 2023, at 08:10, Ye Xiang wrote:

> The minimum code in ASL that covers this board is
> Scope (\_SB.PCI0.DWC3.RHUB.HS01)
>     {
>         Device (GPIO)
>         {
>             Name (_ADR, Zero)
>             Name (_STA, 0x0F)
>         }
>
>         Device (I2C)
>         {
>             Name (_ADR, One)
>             Name (_STA, 0x0F)
>         }
>
>         Device (SPI)
>         {
>             Name (_ADR, 0x02)
>             Name (_STA, 0x0F)
>         }
>     }

I'm a bit confused by this bit, does that mean this only works
if the device is integrated on the mainboard and the BIOS is
aware of it? This won't work if  you plug it into a random
USB port, or have no ACPI firmware, right?

> Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/usb/misc/Kconfig  |  13 +
>  drivers/usb/misc/Makefile |   1 +
>  drivers/usb/misc/ljca.c   | 969 ++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/ljca.h  |  95 ++++

Why is this in driver/usb/misc? It looks like a normal
mfd driver to me, and it evenhas the header in include/linux/mfd/

     Arnd