Linux Input/HID development
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From: Grazvydas Ignotas <notasas@gmail.com>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: linux-input@vger.kernel.org,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-omap@vger.kernel.org
Subject: Re: [PATCH] Input: ads7846: add regulator support
Date: Thu, 4 Feb 2010 16:52:26 +0200	[thread overview]
Message-ID: <6ed0b2681002040652r722e3df2s3f032a9fe0d0c0fe@mail.gmail.com> (raw)
In-Reply-To: <20100204142439.GA1139@sirena.org.uk>

On Thu, Feb 4, 2010 at 4:24 PM, Mark Brown
<broonie@opensource.wolfsonmicro.com> wrote:
> On Thu, Feb 04, 2010 at 03:39:18PM +0200, Grazvydas Ignotas wrote:
>
>> The ADS7846/TSC2046 touchscreen controllers can (and usually are)
>> connected to various regulators for power, so add regulator support.
>> Make it optional for now to avoid breaking all current users of this
>> driver.
>
> This should not be required.  The regulator API stubs itself out when it
> is not built so all API calls report as successful.

ok

>
>> +     ts->reg = regulator_get(&spi->dev, "vcc");
>> +     if (!IS_ERR(ts->reg)) {
>> +             err = regulator_enable(ts->reg);
>> +             if (err)
>> +                     goto err_put_regulator;
>> +     }
>
> If the regulator API is not compiled in then the regulator_get() will
> return succesfully.  If the regulator API is in use then failure to
> acquire the regulator is a serious problem which really should be at a
> minimium be being communicated to the user.  For example, the regulator
> API may end up powering down regulators which it believes are unused or
> the regulator may not be powered by default and needs to be enabled.
>
> The updates to fix up the boards that need this are fairly
> straightforward and given that it's fairly easy to identify systems
> which are using the driver in mainline so I'd really prefer not to go
> down the route of trying to carry on in the face of error, it papers
> over stuff now but is not robust in the face of future changes.

What about warning and continuing only on ENODEV then? I really don't
want to be responsible for potentially breaking touchscreen on ~30
boards, where I have no idea about how things are wired up and how the
regulators should be set up.
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  reply	other threads:[~2010-02-04 14:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-04 13:39 [PATCH] Input: ads7846: add regulator support Grazvydas Ignotas
2010-02-04 14:24 ` Mark Brown
2010-02-04 14:52   ` Grazvydas Ignotas [this message]
2010-02-04 16:21     ` Mark Brown
2010-02-04 18:08       ` Dmitry Torokhov
2010-02-04 18:59         ` Mark Brown
2010-02-05 20:45       ` Mike Rapoport
2010-02-08 11:30         ` Mark Brown
2010-02-09  8:55           ` Mike Rapoport
2010-02-04 15:08   ` Mike Rapoport
2010-02-04 16:03     ` Mark Brown

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