Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v7 00/48] atmel_mxt_ts misc
From:   Dmitry Osipenko <digetx@gmail.com>
To:     "Wang, Jiada" <jiada_wang@mentor.com>, jikos@kernel.org,
        benjamin.tissoires@redhat.com, rydberg@bitmath.org,
        dmitry.torokhov@gmail.com, nick@shmanahar.org, bsz@semihalf.com
Cc:     linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        erosca@de.adit-jv.com, Andrew_Gabbasov@mentor.com
References: <20200212084218.32344-1-jiada_wang@mentor.com>
 <c583d151-9243-cbde-a04b-bc0389d9be5a@gmail.com>
 <89e4bb0b-b2eb-0b67-4307-fb2af914b1c0@mentor.com>
 <f9b221e7-f189-3e47-adab-1cbc49490d4b@gmail.com>
 <bd3c487b-b065-3e4f-6ab1-f344a4113fcd@mentor.com>
 <5d8fdfc1-cc95-59db-b83e-87bb16ea79e8@gmail.com>
Message-ID: <60f89c4e-91e0-e660-58e7-5b152bc3e8e7@gmail.com>
Date:   Tue, 24 Mar 2020 18:03:09 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.5.0
MIME-Version: 1.0
In-Reply-To: <5d8fdfc1-cc95-59db-b83e-87bb16ea79e8@gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

24.03.2020 17:54, Dmitry Osipenko пишет:
> 23.03.2020 05:25, Wang, Jiada пишет:
>> Hello Dmitry
>>
>> On 2020/03/21 0:53, Dmitry Osipenko wrote:
>>> Hello Jiada,
>>>
>>> 20.03.2020 06:37, Wang, Jiada пишет:
>>>> Hello Dmitry
>>>>
>>>> I have submitted v8 patch-set to address your comments towards v7
>>>> patch-set,
>>>> most of checkpatch warnings and errors have been addressed,
>>>>
>>>> But I didn't update for following two types of warnings
>>>> since I want to keep consistency with legacy code
>>>>
>>>> WARNING: DEVICE_ATTR unusual permissions '0600' used
>>>> #290: FILE: drivers/input/touchscreen/atmel_mxt_ts.c:3761:
>>>> +static DEVICE_ATTR(debug_v2_enable, 0600, NULL,
>>>
>>> What will happen if you'll use 0644? Will an empty line be returned or
>>> driver will crash?
>>>
>> debug_v2_enable doesn't have .show callback implemented, so after change
>> permission to 644, read of it results in an I/O error,
>>
>> for other 0600 permission interfaces (t38_data, t25 and debug_enable)
>> added in this series,
>> change to 644 can return expected information when read.
>>
>> Do you think it's better to change debug_v2_enable to 0200,
>> and others to 0644?
> 
> Since the debug_enable has mxt_debug_enable_show(), the same should be
> done for debug_v2_enable, for consistency.
> 
> The permissions should be 0644 for everything that is read/write.
> 
> The 0200 should be used for everything that is root-only and write-only.
> 

Also, please take a look at [1], see DEVICE_ATTR_WO() and
DEVICE_BOOL_ATTR() macros, which should be handy.

[1]
https://elixir.bootlin.com/linux/v5.6-rc7/source/include/linux/device.h#L125