lkml.org 
[lkml]   [2018]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v6 2/3] drm: bridge: Add thc63lvd1024 LVDS decoder driver
Hi Andrzej,

On Tue, Mar 27, 2018 at 9:28 AM, Andrzej Hajda <a.hajda@samsung.com> wrote:
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c

>>> +static void thc63_enable(struct drm_bridge *bridge)
>>> +{
>>> + struct thc63_dev *thc63 = to_thc63(bridge);
>>> + struct regulator *vcc;
>>> + int i;
>> unsigned int i;
>
> Why? You are introducing silly bug this way, see few lines below.
>
>>
>>> +
>>> + for (i = 0; i < ARRAY_SIZE(thc63->vccs); i++) {
>>> + vcc = thc63->vccs[i];
>>> + if (!vcc)
>>> + continue;
>>> +
>>> + if (regulator_enable(vcc))
>>> + goto error_vcc_enable;
>>> + }
>>> +
>>> + if (thc63->pdwn)
>>> + gpiod_set_value(thc63->pdwn, 0);
>>> +
>>> + if (thc63->oe)
>>> + gpiod_set_value(thc63->oe, 1);
>>> +
>>> + return;
>>> +
>>> +error_vcc_enable:
>>> + dev_err(thc63->dev, "Failed to enable regulator %s\n",
>>> + thc63_reg_names[i]);
>>> +
>>> + for (i = i - 1; i >= 0; i--) {
>
> Here, the loop will not end if you define i unsigned.

True.

> I know one can change the loop, to make it working with unsigned. But
> this clearly shows that using unsigned is more risky.
> What are advantages of unsigned vs int in this case. Are there some
> guidelines/discussions about it?

Some people consider signed integers harmful, as they may be converted
silently by the compiler to the "larger" unsigned type when needed.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

\
 
 \ /
  Last update: 2018-03-27 09:36    [W:0.074 / U:28.812 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site