2018-07-30 13:47:31

by Jia-Ju Bai

[permalink] [raw]

Subject: [PATCH] power: reset: gpio-poweroff: Replace mdelay() with msleep() in gpio_poweroff_do_poweroff()

---

gpio_poweroff_do_poweroff() is never called in atomic context.
It calls mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep().

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/power/reset/gpio-poweroff.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
index 6273ad3b411d..bbe55cfa87d0 100644
--- a/drivers/power/reset/gpio-poweroff.c
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -33,16 +33,16 @@ static void gpio_poweroff_do_poweroff(void)

/* drive it active, also inactive->active edge */
gpiod_direction_output(reset_gpio, 1);
- mdelay(100);
+ msleep(100);
/* drive inactive, also active->inactive edge */
gpiod_set_value(reset_gpio, 0);
- mdelay(100);
+ msleep(100);

/* drive it active, also inactive->active edge */
gpiod_set_value(reset_gpio, 1);

/* give it some time */
- mdelay(timeout);
+ msleep(timeout);

WARN_ON(1);
}
--
2.17.0

2018-08-29 22:46:31

by Sebastian Reichel

[permalink] [raw]

Subject: Re: [PATCH] power: reset: gpio-poweroff: Replace mdelay() with msleep() in gpio_poweroff_do_poweroff()

---

Hi,

On Mon, Jul 30, 2018 at 09:46:14PM +0800, Jia-Ju Bai wrote:
> gpio_poweroff_do_poweroff() is never called in atomic context.
> It calls mdelay() to busily wait, which is not necessary.
> mdelay() can be replaced with msleep().
>
> This is found by a static analysis tool named DCNS written by myself.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---

Please self-review the results from your tool before sending.
This is a shutdown driver.

-- Sebastian

> drivers/power/reset/gpio-poweroff.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
> index 6273ad3b411d..bbe55cfa87d0 100644
> --- a/drivers/power/reset/gpio-poweroff.c
> +++ b/drivers/power/reset/gpio-poweroff.c
> @@ -33,16 +33,16 @@ static void gpio_poweroff_do_poweroff(void)
>
> /* drive it active, also inactive->active edge */
> gpiod_direction_output(reset_gpio, 1);
> - mdelay(100);
> + msleep(100);
> /* drive inactive, also active->inactive edge */
> gpiod_set_value(reset_gpio, 0);
> - mdelay(100);
> + msleep(100);
>
> /* drive it active, also inactive->active edge */
> gpiod_set_value(reset_gpio, 1);
>
> /* give it some time */
> - mdelay(timeout);
> + msleep(timeout);
>
> WARN_ON(1);
> }
> --
> 2.17.0
>

---

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