Re: [PATCH 10/10] drivers: misc: use module_platform_driver_probe()

From: Fabio Porcedda
Date: Mon Mar 18 2013 - 06:03:51 EST


On Fri, Mar 15, 2013 at 9:18 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Friday 15 March 2013, H Hartley Sweeten wrote:
>> Arnd,
>>
>> Ill look at converting the ep93xx pwm driver to the PWM subsystem. The only issue is
>> the current driver exposes a sysfs interface that I think is not available in that subsystem.
>
> You can probably keep providing that interface if you have active users.
>
>> >* Regarding the use of module_platform_driver_probe, I'm a little worried about
>> > the interactions with deferred probing. I don't think there are any regressions,
>> > but we should probably make people aware that one cannot return -EPROBE_DEFER
>> > from a platform_driver_probe function.
>>
>> The ep93xx pwm driver does not need to use platform_driver_probe(). It can be changed
>> to use module_platform_driver() by just moving the .probe to the platform_driver. This
>> driver was added before module_platform_driver() was available and I used the
>> platform_driver_probe() thinking it would save a couple lines of code.

Since by using platform_driver_probe() the function
ep93xx_pwm_probe() is freed after initialization,
is better to use module_platform_drive_probe().
IMHO i don't see any good reason to use module_platform_driver() for
this driver.

Best regards
Fabio Porcedda

>> I'll change this in a bit. Right now I'm trying to work out why kernel 3.8 is not booting
>> on the ep93xx. I had 3.6.6 on my development board and 3.7 works fine but 3.8 hangs
>> without uncompressing the kernel.
>
> Ok, thanks!
>
> Arnd
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