From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757716AbcLUNL4 (ORCPT ); Wed, 21 Dec 2016 08:11:56 -0500 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:59738 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757170AbcLUNLo (ORCPT ); Wed, 21 Dec 2016 08:11:44 -0500 Subject: Re: [PATCH] at86rf230: Allow slow GPIO pins for "rstn" To: Andrey Smirnov , linux-wpan@vger.kernel.org References: <1482103533-13187-1-git-send-email-andrew.smirnov@gmail.com> Cc: Alexander Aring , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Healy From: Stefan Schmidt Message-ID: <7435a0a2-3f0f-a0db-9e0e-cb1ac838737c@osg.samsung.com> Date: Wed, 21 Dec 2016 14:11:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1482103533-13187-1-git-send-email-andrew.smirnov@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 19/12/16 00:25, Andrey Smirnov wrote: > Driver code never touches "rstn" signal in atomic context, so there's > no need to implicitly put such restriction on it by using gpio_set_value > to manipulate it. Replace gpio_set_value to gpio_set_value_cansleep to > fix that. We need to make sure we are not assuming it can be called in such a context in the future now. But that is something we can worry about if it comes up. > As a an example of where such restriction might be inconvenient, > consider a hardware design where "rstn" is connected to a pin of I2C/SPI > GPIO expander chip. Is this a real life issue you run into? > Cc: Chris Healy > Signed-off-by: Andrey Smirnov > --- > drivers/net/ieee802154/at86rf230.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c > index 9f10da6..7700690 100644 > --- a/drivers/net/ieee802154/at86rf230.c > +++ b/drivers/net/ieee802154/at86rf230.c > @@ -1710,9 +1710,9 @@ static int at86rf230_probe(struct spi_device *spi) > /* Reset */ > if (gpio_is_valid(rstn)) { > udelay(1); > - gpio_set_value(rstn, 0); > + gpio_set_value_cansleep(rstn, 0); > udelay(1); > - gpio_set_value(rstn, 1); > + gpio_set_value_cansleep(rstn, 1); > usleep_range(120, 240); > } > > Acked-by: Stefan Schmidt regards Stefan Schmidt