From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1710FC433ED for ; Wed, 12 May 2021 03:16:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D870061182 for ; Wed, 12 May 2021 03:16:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230096AbhELDRy (ORCPT ); Tue, 11 May 2021 23:17:54 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:51860 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229848AbhELDRx (ORCPT ); Tue, 11 May 2021 23:17:53 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0UYbG6OP_1620789403; Received: from B-X3VXMD6M-2058.local(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0UYbG6OP_1620789403) by smtp.aliyun-inc.com(127.0.0.1); Wed, 12 May 2021 11:16:44 +0800 From: Xin Hao Reply-To: xhao@linux.alibaba.com Subject: Re: [PATCH v2 1/1] spi: Assume GPIO CS active high in ACPI case To: Andy Shevchenko , Mark Brown , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Liguang Zhang , Jay Fang , Sven Van Asbroeck References: <20210511140912.30757-1-andriy.shevchenko@linux.intel.com> Message-ID: Date: Wed, 12 May 2021 11:16:43 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: <20210511140912.30757-1-andriy.shevchenko@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/5/11 下午10:09, Andy Shevchenko 写道: > Currently GPIO CS handling, when descriptors are in use, doesn't > take into consideration that in ACPI case the default polarity > is Active High and can't be altered. Instead we have to use the > per-chip definition provided by SPISerialBus() resource. > > Fixes: 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") > Cc: Liguang Zhang > Cc: Jay Fang > Cc: Sven Van Asbroeck > Signed-off-by: Andy Shevchenko > Tested-by: Xin Hao > --- > v2: refactor to avoid ternary (Mark, Sven), dropped comment changes (Mark) > drivers/spi/spi.c | 22 ++++++++++++++++++---- > 1 file changed, 18 insertions(+), 4 deletions(-) > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index cd40421b8f55..36ee33514b40 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -820,15 +820,29 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force) > > if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) { > if (!(spi->mode & SPI_NO_CS)) { > - if (spi->cs_gpiod) > - /* polarity handled by gpiolib */ > - gpiod_set_value_cansleep(spi->cs_gpiod, activate); > - else > + if (spi->cs_gpiod) { > + /* > + * Historically ACPI has no means of the GPIO polarity and > + * thus the SPISerialBus() resource defines it on the per-chip > + * basis. In order to avoid a chain of negations, the GPIO > + * polarity is considered being Active High. Even for the cases > + * when _DSD() is involved (in the updated versions of ACPI) > + * the GPIO CS polarity must be defined Active High to avoid > + * ambiguity. That's why we use enable, that takes SPI_CS_HIGH > + * into account. > + */ > + if (has_acpi_companion(&spi->dev)) > + gpiod_set_value_cansleep(spi->cs_gpiod, !enable); it worked and code changed minimally,  before ACPI & OF keeps no same rules,  this patch is ok! > + else > + /* Polarity handled by GPIO library */ > + gpiod_set_value_cansleep(spi->cs_gpiod, activate); > + } else { > /* > * invert the enable line, as active low is > * default for SPI. > */ > gpio_set_value_cansleep(spi->cs_gpio, !enable); > + } > } > /* Some SPI masters need both GPIO CS & slave_select */ > if ((spi->controller->flags & SPI_MASTER_GPIO_SS) && -- Best Regards! Xin Hao