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SubjectRe: [PATCH v2] net: dsa: b53: Using sleep-able operations in b53_switch_reset_gpio
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On 12/04/2018 09:48, Jia-Ju Bai wrote:
> b53_switch_reset_gpio() is never called in atomic context.
>
> The call chain ending up at b53_switch_reset_gpio() is:
> [1] b53_switch_reset_gpio() <- b53_switch_reset() <-
> b53_reset_switch() <- b53_setup()
>
> b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops.
> This function is not called in atomic context.
>
> Despite never getting called from atomic context, b53_switch_reset_gpio()
> calls non-sleep operations mdelay() and gpio_set_value().
> They are not necessary and can be replaced with msleep()
> and gpio_set_value_cansleep().
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
> v2:
> * Use gpio_set_value_cansleep() to replace gpio_set_value() additionally.
> Thanks for Florian and Phil for good advice.
> ---
> drivers/net/dsa/b53/b53_common.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> index 274f367..36cc60d 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -596,11 +596,11 @@ static void b53_switch_reset_gpio(struct b53_device *dev)
>
> /* Reset sequence: RESET low(50ms)->high(20ms)
> */
> - gpio_set_value(gpio, 0);
> - mdelay(50);
> + gpio_set_value_cansleep(gpio, 0);
> + msleep(50);
>
> - gpio_set_value(gpio, 1);
> - mdelay(20);
> + gpio_set_value_cansleep(gpio, 1);
> + msleep(20);
>
> dev->current_page = 0xff;
> }
>

FWIW:
Reviewed-by: Phil Reid <preid@electromag.com.au>

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