From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jia-Ju Bai Subject: Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio Date: Wed, 11 Apr 2018 15:14:34 +0800 Message-ID: <7c9dffb7-d55a-98f5-4024-7e2f0c704a56@gmail.com> References: <1523411485-2030-1-git-send-email-baijiaju1990@gmail.com> <11d079ab-3c07-a10d-c321-f873c53e9690@electromag.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Phil Reid , f.fainelli@gmail.com, andrew@lunn.ch, vivien.didelot@savoirfairelinux.com Return-path: Received: from mail-pf0-f195.google.com ([209.85.192.195]:42227 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752095AbeDKHOx (ORCPT ); Wed, 11 Apr 2018 03:14:53 -0400 In-Reply-To: <11d079ab-3c07-a10d-c321-f873c53e9690@electromag.com.au> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 2018/4/11 13:30, Phil Reid wrote: > On 11/04/2018 09:51, 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 mdelay() to busily wait. >> This is not necessary and can be replaced with msleep() to >> avoid busy waiting. >> >> 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 >> --- >> drivers/net/dsa/b53/b53_common.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/net/dsa/b53/b53_common.c >> b/drivers/net/dsa/b53/b53_common.c >> index 274f367..e070ff6 100644 >> --- a/drivers/net/dsa/b53/b53_common.c >> +++ b/drivers/net/dsa/b53/b53_common.c >> @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct >> b53_device *dev) >> /* Reset sequence: RESET low(50ms)->high(20ms) >> */ >> gpio_set_value(gpio, 0); >> - mdelay(50); >> + msleep(50); >> gpio_set_value(gpio, 1); >> - mdelay(20); >> + msleep(20); >> dev->current_page = 0xff; >> } >> > Would that also imply gpio_set_value could be gpio_set_value_cansleep? > Yes, I think gpio_set_value_cansleep() is okay here? Do I need to send a V2 patch to replace gpio_set_value()? Best wishes, Jia-Ju Bai