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Date:   Wed, 12 Apr 2023 13:10:33 +0200
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Subject: Re: [PATCH v7 3/6] Documentation: Add ABI doc for attributes of LJCA
 device
To:     "Ye, Xiang" <xiang.ye@intel.com>, Oliver Neukum <oneukum@suse.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        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,
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        linux-spi@vger.kernel.org, linux-gpio@vger.kernel.org,
        srinivas.pandruvada@intel.com, heikki.krogerus@linux.intel.com,
        andriy.shevchenko@linux.intel.com, sakari.ailus@linux.intel.com,
        zhifeng.wang@intel.com, wentong.wu@intel.com, lixu.zhang@intel.com
References: <20230325154711.2419569-1-xiang.ye@intel.com>
 <20230325154711.2419569-4-xiang.ye@intel.com>
 <b1eb8356-4519-4c95-b3ee-afc142b8d17f@suse.com>
 <ZDPoku+k+S65cmeQ@ye-NUC7i7DNHE>
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From:   Oliver Neukum <oneukum@suse.com>
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On 10.04.23 12:44, Ye, Xiang wrote:

Hi,

>> do we really want each driver to have its own attribute for that?
>> It seems to me that that should be unified.
> Three ABI entries are added in this patch: ljca_version, ljca_trace_level,
> and ljca_enable_dfu. The first two items are specified for LJCA device and
> I think they can be kept in sysfs-bus-usb-devices-ljca.
> 
> But for ljca_enable_dfu, I didn't see a unified DFU entry in sys-bus-usb.
> I am not sure whether other USB devices have similar DFU mode or not.
> 
> Any suggestions?

What exactly does this attribute do?
Is it in addition to the normal DFU_DETACH + reset sequence, is it
needed for DFU_DETACH to work, does it enable the
DFU class interface descriptor?

A point of DFU is rather that the capability should be announced
via descriptors. The answer would depend on what exactly this
attribute does.

	Regards
		Oliver