Re: [PATCH 08/18] [media] s5c73m3: Export OF module alias information

From: Javier Martinez Canillas <javier@osg.samsung.com>
To: Andrzej Hajda <a.hajda@samsung.com>, linux-kernel@vger.kernel.org
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH 08/18] [media] s5c73m3: Export OF module alias information
Date: Fri, 11 Sep 2015 12:33:17 +0200	[thread overview]
Message-ID: <55F2ADED.8030704@osg.samsung.com> (raw)
In-Reply-To: <55F2A89C.6090102@samsung.com>

Hello Andrzej,

On 09/11/2015 12:10 PM, Andrzej Hajda wrote:
> On 09/11/2015 03:19 AM, Javier Martinez Canillas wrote:
>> Hello,
>>
>> On 08/20/2015 09:07 AM, Javier Martinez Canillas wrote:
>>> The SPI core always reports the MODALIAS uevent as "spi:<modalias>"
>>> regardless of the mechanism that was used to register the device
>>> (i.e: OF or board code) and the table that is used later to match
>>> the driver with the device (i.e: SPI id table or OF match table).
>>>
>>> So drivers needs to export the SPI id table and this be built into
>>> the module or udev won't have the necessary information to autoload
>>> the needed driver module when the device is added.
>>>
>>> But this means that OF-only drivers needs to have both OF and SPI id
>>> tables that have to be kept in sync and also the dev node compatible
>>> manufacturer prefix is stripped when reporting the MODALIAS. Which can
>>> lead to issues if two vendors use the same SPI device name for example.
>>>
>>> To avoid the above, the SPI core behavior may be changed in the future
>>> to not require an SPI device table for OF-only drivers and report the
>>> OF module alias. So, it's better to also export the OF table even when
>>> is unused now to prevent breaking module loading when the core changes.
>>>
>>> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
>>> ---
>>>
>>>  drivers/media/i2c/s5c73m3/s5c73m3-spi.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/media/i2c/s5c73m3/s5c73m3-spi.c b/drivers/media/i2c/s5c73m3/s5c73m3-spi.c
>>> index fa4a5ebda6b2..9983635ec253 100644
>>> --- a/drivers/media/i2c/s5c73m3/s5c73m3-spi.c
>>> +++ b/drivers/media/i2c/s5c73m3/s5c73m3-spi.c
>>> @@ -31,6 +31,7 @@ static const struct of_device_id s5c73m3_spi_ids[] = {
>>>  	{ .compatible = "samsung,s5c73m3" },
>>>  	{ }
>>>  };
>>> +MODULE_DEVICE_TABLE(of, s5c73m3_spi_ids;);
> 
> Unnecessary semicolon inside parenthesis, I guess it wont compile :)
>

Sigh, sorry for that. I did build test but with CONFIG_VIDEO_S5C73M3=y
instead of CONFIG_VIDEO_S5C73M3=m so I didn't notice that silly typo.

I'll post a v2, thanks a lot for spotting this!

> Regards
> Andrzej
> 

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America