Re: [PATCH v2 2/2] IIO: st_accel_i2c.c: Use probe_new() instead of probe()

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Xiongfeng Wang <xiongfeng.wang@linaro.org>,
	linux-iio@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	nv@vosn.de
Subject: Re: [PATCH v2 2/2] IIO: st_accel_i2c.c: Use probe_new() instead of probe()
Date: Wed, 4 Jul 2018 12:16:12 +0300	[thread overview]
Message-ID: <CAHp75VdxtfkrV0bT=4yeYcSUFncTvjBfVC1haOUPpdOaOohmLg@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1807041100360.7891@fox.voss.local>

On Wed, Jul 4, 2018 at 12:09 PM, Nikolaus Voss
<nikolaus.voss@loewensteinmedical.de> wrote:
> On Wed, 4 Jul 2018, Andy Shevchenko wrote:
>>
>> On Wed, Jul 4, 2018 at 9:37 AM, Nikolaus Voss
>> <nikolaus.voss@loewensteinmedical.de> wrote:
>>>
>>> On Wed, 4 Jul 2018, Andy Shevchenko wrote:
>>>>
>>>>
>>>> On Tue, Jul 3, 2018 at 9:06 AM, Nikolaus Voss
>>>> <nikolaus.voss@loewensteinmedical.de> wrote:
>>>>>
>>>>>
>>>>> struct i2c_device_id argument of probe() is not used, so use
>>>>> probe_new()
>>>>> instead.
>>>>>
>>>>
>>>> This makes...
>>>>
>>>>>  MODULE_DEVICE_TABLE(i2c, st_accel_id_table);
>>>>
>>>>
>>>>
>>>> ...this table obsolete IIUC. At least that's what I did when switched
>>>> to ->probe_new() in some drivers.
>>>>
>>>> If I'm mistaken (again? :-) ) I would hear from someone to point me
>>>> how it can be used after a switch.
>>>
>>>
>>>
>>> It is still used by the i2c-core in i2c_device_match() if DT and ACPI
>>> matching fails.
>>
>>
>>> And it is used to create the corresponding modaliases for
>>> driver loading.
>>
>>
>> My question is "How?!"
>> I don't really see any points to match against it after switching to
>> ->probe_new().
>>
>> Could you point me to the code path in i2c (or OF?) core for that?
>
>
> As written above in i2c-core-base.c: i2c_device_match() ->
> i2c_match_id(driver->id_table,...
>
> This is used for driver matching before probe() or probe_new() of the device
> driver can be called. probe_new() actually is a function signature change
> only.

Okay, IIUC we got a match. What should we do with it? The table is not
used in ->probe_new() (in i2c core), so, you can't say which line
matched there.

-- 
With Best Regards,
Andy Shevchenko