From: Trent Piepho <tpiepho@freescale.com>
To: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [patch/rfc 2/4] pcf875x I2C GPIO expander driver
Date: Fri, 4 Apr 2008 13:18:14 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0804041302200.20532@t2.domain.actdsltmp> (raw)
In-Reply-To: <20080404213632.300eb3de@hyperion.delvare>
On Fri, 4 Apr 2008, Jean Delvare wrote:
> On Fri, 4 Apr 2008 12:07:12 -0700 (PDT), Trent Piepho wrote:
>> On Fri, 4 Apr 2008, Jean Delvare wrote:
>>> On Thu, 3 Apr 2008 19:06:27 -0700 (PDT), Trent Piepho wrote:
>>>> + strcpy(buf, test_bit(FLAG_IS_OUT, &gdesc->flags) ? "out\n" : "in\n\0");
>>>> +
>>>> + return 5;
>>>
>>> Confusing construct... I suggest using sprintf instead, which will
>>> automatically return the correct number of bytes for you.
>>
>> But it's less efficient! Will nobody think of the wasted cycles?
>
> Can you prove that it is actually less efficient, and if so, by how
> much? The time spent in this single function if probably insignificant
I think sprintf will parse the format string, and then end up calling the same
strcpy() call to handle a %s. Since sprintf() contains the strcpy(), it has
to be slower than strcpy alone.
But I should have put a :) in there, as I changed this code.
> thread, you aren't support to include trailing \0s in the buffer you
> pass back to sysfs. Not all programming languages use \0 for string
> termination.
I fixed all those. I wasn't clear on that when I wrote this code and forgot I
had done it incorrectly.
>>>> + /* FIXME: Code to remove all the sysfs devices and files created
>>>> + * should go here */
>>>
>>> Oh yes it really should ;)
>>
>> I know, but I'm not using modules for the system this is in, so it will never
>> get called. What's the point of writing code I'll never use if this isn't
>> useful for the kernel?
>
> Because most certainly your code won't be accepted upstream until this
> is fixed, and presumably you posted this patch in the hope that it
> would go upstream ;) Just because it isn't useful to you doesn't mean
> it won't be useful to others. Otherwise this particular piece of code
> couldn't be built as a module at all.
I guess I was waiting for a "this could go upstream if you fix this" or "this
won't go upstream even if you fix it" so I don't waste time writing code no
one is interested in.
next prev parent reply other threads:[~2008-04-04 20:19 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200710291809.29936.david-b@pacbell.net>
2007-10-30 1:51 ` [patch/rfc 1/4] GPIO implementation framework David Brownell
2007-11-05 21:05 ` David Brownell
2007-11-13 2:28 ` eric miao
2007-11-13 19:06 ` David Brownell
2007-11-14 0:57 ` eric miao
2007-11-14 1:00 ` eric miao
2007-11-14 1:02 ` eric miao
2007-11-14 1:03 ` eric miao
2007-11-14 1:04 ` eric miao
2007-11-14 1:04 ` eric miao
2007-11-14 4:36 ` David Brownell
2007-11-14 6:51 ` eric miao
2007-11-14 7:19 ` David Brownell
2007-11-14 7:36 ` eric miao
2007-11-17 10:38 ` Jean Delvare
2007-11-17 17:36 ` David Brownell
2007-11-20 15:20 ` Jean Delvare
2007-11-14 4:18 ` David Brownell
2007-11-14 6:46 ` eric miao
2007-11-14 3:28 ` David Brownell
2007-11-14 3:25 ` David Brownell
2007-11-14 3:53 ` David Brownell
2007-11-14 6:37 ` eric miao
2007-11-14 3:30 ` David Brownell
2007-11-14 6:40 ` eric miao
2007-11-14 7:08 ` David Brownell
2007-11-27 1:46 ` David Brownell
2007-11-27 10:58 ` eric miao
2007-11-27 17:26 ` David Brownell
2007-11-27 19:03 ` David Brownell
2007-11-27 19:29 ` David Brownell
2007-11-28 5:11 ` eric miao
2007-11-28 3:15 ` [patch/rfc 2.6.24-rc3-mm] gpiolib grows a gpio_desc David Brownell
2007-11-28 9:10 ` eric miao
2007-11-28 9:53 ` David Brownell
2007-10-30 1:51 ` [patch/rfc 2/4] pcf875x I2C GPIO expander driver David Brownell
2007-11-30 12:32 ` Jean Delvare
2007-11-30 13:04 ` Bill Gatliff
2007-11-30 13:36 ` Jean Delvare
2007-11-30 14:09 ` Bill Gatliff
2007-11-30 18:40 ` David Brownell
2007-11-30 20:13 ` Jean Delvare
2007-11-30 20:59 ` David Brownell
2008-04-04 2:06 ` Trent Piepho
2008-04-04 2:45 ` Ben Nizette
2008-04-04 3:33 ` Trent Piepho
2008-04-04 4:57 ` Ben Nizette
2008-04-05 4:05 ` userspace GPIO access (WAS: [patch/rfc 2/4] pcf875x ...) David Brownell
2008-04-07 17:56 ` Trent Piepho
2008-04-04 8:09 ` [patch/rfc 2/4] pcf875x I2C GPIO expander driver Jean Delvare
2008-04-04 19:07 ` Trent Piepho
2008-04-04 19:36 ` Jean Delvare
2008-04-04 20:18 ` Trent Piepho [this message]
2008-04-05 2:51 ` David Brownell
2008-04-05 2:53 ` David Brownell
2007-12-06 3:03 ` [patch/rfc 2/4] pcf857x " David Brownell
2007-12-06 23:17 ` Jean Delvare
2007-12-07 4:02 ` David Brownell
2007-10-30 1:53 ` [patch/rfc 3/4] DaVinci platform uses new GPIOLIB David Brownell
2007-10-30 1:54 ` [patch/rfc 4/4] DaVinci EVM uses pcf857x GPIO driver David Brownell
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