From: John Stultz <john.stultz@linaro.org>
To: Paul Mundt <lethal@linux-sh.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Arve Hj??nnev??g <arve@android.com>,
Russell King <linux@arm.linux.org.uk>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [PATCH 01/15] ARM: etm: Don't require clock control
Date: Wed, 13 Jun 2012 16:09:13 -0700 [thread overview]
Message-ID: <4FD91D99.8050706@linaro.org> (raw)
In-Reply-To: <20120613083330.GB27673@linux-sh.org>
On 06/13/2012 01:33 AM, Paul Mundt wrote:
> On Tue, Jun 12, 2012 at 07:01:19PM -0700, John Stultz wrote:
>> diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
>> index 36d20bd..bd295e8 100644
>> --- a/arch/arm/kernel/etm.c
>> +++ b/arch/arm/kernel/etm.c
>> @@ -362,13 +362,12 @@ static int __devinit etb_probe(struct amba_device *dev, const struct amba_id *id
>> if (ret)
>> goto out_unmap;
>>
>> + /* Get optional clock. Currently used to select clock source on omap3 */
>> t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
>> - if (IS_ERR(t->emu_clk)) {
>> + if (IS_ERR(t->emu_clk))
>> dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
>> - return -EFAULT;
>> - }
>> -
>> - clk_enable(t->emu_clk);
>> + else
>> + clk_enable(t->emu_clk);
>>
> Optionally you could just:
>
> if (IS_ERR(t->emu_clk))
> t->emu_clk = NULL;
>
> and use the clk API as you were, as it does handle NULL being passed in.
>
> In this case you don't have too many callsites to worry about, but it's
> reasonably convenient to be able to pass a NULL clk pointer around
> without constant special-casing when those start to balloon up.
>
Hrm. That's a good trick to remember for the future!
Although in this case I'm not sure it wins much (since the re-adding of
the braces and the null assignment is still more code then using the
else). So unless this is a major style problem for you (and do let me
know if it is), I'll probably leave it alone.
thanks
-john
next prev parent reply other threads:[~2012-06-13 23:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-13 2:01 [PATCH 00/15][RFC] Android ETM driver changes John Stultz
2012-06-13 2:01 ` [PATCH 01/15] ARM: etm: Don't require clock control John Stultz
2012-06-13 8:33 ` Paul Mundt
2012-06-13 23:09 ` John Stultz [this message]
2012-06-13 2:01 ` [PATCH 02/15] ARM: etm: Don't limit tracing to only non-secure code John Stultz
2012-06-13 2:01 ` [PATCH 03/15] ARM: etm: Don't try to clear the buffer full status after reading the buffer John Stultz
2012-06-13 2:01 ` [PATCH 04/15] ARM: etm: Allow range selection John Stultz
2012-06-13 2:01 ` [PATCH 05/15] ARM: etm: Configure data tracing John Stultz
2012-06-13 2:01 ` [PATCH 06/15] ARM: etm: Add some missing locks and error checks John Stultz
2012-06-13 2:01 ` [PATCH 07/15] ARM: etm: Return the entire trace buffer if it is empty after reset John Stultz
2012-06-13 2:01 ` [PATCH 08/15] ARM: etm: Support multiple ETMs/PTMs John Stultz
2012-06-13 2:01 ` [PATCH 09/15] ARM: etm: Power down etm(s) when tracing is not enabled John Stultz
2012-06-28 16:13 ` [PATCH 00/15][RFC] Android ETM driver changes Linus Walleij
2012-06-29 20:25 ` John Stultz
-- strict thread matches above, loose matches on Subject: below --
2012-06-20 22:47 [PATCH 00/15] " John Stultz
2012-06-20 22:47 ` [PATCH 01/15] ARM: etm: Don't require clock control John Stultz
2012-06-28 15:47 ` Linus Walleij
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