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From: Gregory CLEMENT <>
To: Mark Brown <>
Cc: Liam Girdwood <>,,
	Thomas Petazzoni <>,
	Ezequiel Garcia <>,
	Maxime Ripard <>,
	Boris BREZILLON <>,
	Lior Amsalem <>,
	Tawfik Bayouk <>,
	Nadav Haklai <>,
Subject: Re: [PATCH 1/2] regulator: core: Add a sanity check on the regulator_ enable/disable functions
Date: Tue, 06 Jan 2015 13:26:28 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hi Mark,

On 06/01/2015 13:00, Mark Brown wrote:
> On Tue, Jan 06, 2015 at 12:36:02PM +0100, Gregory CLEMENT wrote:
>> Hi Mark,
>> On 29/12/2014 16:40, Mark Brown wrote:
>>> On Fri, Dec 26, 2014 at 06:26:38PM +0100, Gregory CLEMENT wrote:
>>> No, especially in the case of regulator_enable() this is deliberate -
>>> we're trying to ensure that if people are using regulators they're being
>>> careful about it, checking error codes and so on.  I'd really want to
>> OK so at least we should check that the pointer is not NULL before using it
>> and inform the user of it by using a WARNING() or even a BUG() instead of
>> just let the kernel crash latter.
> Just crashing on the NULL is just about as good in terms of
> discoverabilty and any consumer that is assuming NULL is not a valid
> regulator is buggy in any case, any non-error pointer could be a valid
> regulator as far as users are concerned.  
>>> see some persuasive use case for this.  What you're saying here sounds
>>> like the consumer shouldn't be treating the regulator as optional at
>>> all but should instead be using a normal regulator.
>> Being able to deal with NULL pointer in the disable function is convenient
>> and is done in other similar subsystems such as phy or clk for example. Instead
>> of having a check on the NULL pointer in each driver, it seems more logical to
>> do it directly in the disable function.
> This really only applies if it's likely that some thing that always gets
> used if it's there might be missing which isn't the case for regulators,
> it's not at all common to have power supplies that might be missing and

Well the pattern the following pattern is very common in the drivers using
the regulator:

if (!IS_ERR(regulator_pointer)

So for me it was a good hint that we can factorize it.

> if they are missing NULL isn't a good way to track them.
> If you're having problems with this and need workarounds in the core to
> make your driver code look OK that sounds like things are working since
> it sounds like the driver code is probably abusing the API here.

I don't _need_ it at all. It was just an improvement but if you don't want it,
I am fine with it.



Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.

  reply	other threads:[~2015-01-06 12:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-26 17:26 Gregory CLEMENT
2014-12-26 17:26 ` [PATCH 1/2] regulator: core: Add a sanity check on the regulator_ enable/disable functions Gregory CLEMENT
2014-12-29 15:40   ` Mark Brown
2015-01-06 11:36     ` Gregory CLEMENT
2015-01-06 12:00       ` Mark Brown
2015-01-06 12:26         ` Gregory CLEMENT [this message]
2015-01-06 16:03           ` Mark Brown
2014-12-26 17:26 ` [PATCH 2/2] regulator: core: Add the device tree version to the regulator_get family Gregory CLEMENT
2014-12-29 15:49   ` Mark Brown

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