From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Wahren Subject: Re: [PATCH V2 6/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported Date: Mon, 25 Mar 2019 11:28:01 +0100 Message-ID: <1e83f4f4-f9ae-2d77-3729-2343a4975e20@i2se.com> References: <20190324175002.28969-1-kernel@martin.sperl.org> <20190324175002.28969-7-kernel@martin.sperl.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernel@martin.sperl.org, Mark Brown , Eric Anholt , Hubert Denkmair , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Return-path: In-Reply-To: <20190324175002.28969-7-kernel@martin.sperl.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org Hi Martin, Am 24.03.19 um 18:49 schrieb kernel@martin.sperl.org: > From: Martin Sperl > > From personal bad experience (even as the author of the original driver) > it shows that native-cs is "somewhat" supported by the spi bus driver > when using a buggy device tree. > > So make sure that the driver is warning in dmesg about this fact > that we are running in a not supported mode that may have surprizing > limitations. > > Signed-off-by: Martin Sperl > Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e please use a proper fixes tag. > --- > drivers/spi/spi-bcm2835aux.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c > index c8acde017b6a..6af07dec5fdc 100644 > --- a/drivers/spi/spi-bcm2835aux.c > +++ b/drivers/spi/spi-bcm2835aux.c > @@ -396,6 +396,38 @@ static void bcm2835aux_spi_handle_err(struct spi_master *master, > bcm2835aux_spi_reset_hw(bs); > } > > +static int bcm2835aux_spi_setup(struct spi_device *spi) > +{ > + int ret; > + > + if (spi->mode & SPI_NO_CS) > + return 0; > + /* sanity check for native cs */ > + if (!gpio_is_valid(spi->cs_gpio)) { > + /* for dt-backwards compatibility: only support native on CS0 > + * known things not supported with broken native CS: > + * * multiple chip-selects: cs0-cs2 are all > + * simultaniously asserted whenever there is a transfer > + * this even includes SPI_NO_CS > + * * SPI_CS_HIGH: cs are always asserted low > + * * cs_change: cs is deasserted after each spi_transfer > + * * cs_delay_usec: cs is always deasserted one SCK cycle > + * after the last transfer > + * probably more... > + */ > + if (spi->chip_select == 0) { > + dev_err(&spi->dev, > + "native CS is not supported but may work for some use-cases for cs = 0 - please define a valid value cs-gpios in DT for complete feature set\n"); > + return 0; These messages are rather too long, please keep it in the ~ 80 char limit (in source code and dmesg). Or make it two lines ... Since we return with 0, i prefer to use dev_warn instead of dev_err. Thanks > + } > + dev_err(&spi->dev, > + "native CS is not supported for cs > 0 - please define a valid value cs-gpios in DT to enable multiple cs\n"); > + return -EINVAL; > + } > + > + return 0; > +} > + 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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham 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 BC418C43381 for ; Mon, 25 Mar 2019 10:28:31 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5657D20850 for ; Mon, 25 Mar 2019 10:28:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="E0yV8seG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5657D20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=i2se.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Cc:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=UyoEyhx1UdBSUmanyP/XQb8MOgYxe4frh4f3hwAOg/U=; b=E0yV8seGmoCBBzo9ZJFKdkioXl FtKHNWQJ1tRNa/ckX+LIBqC/K9BmJ4WfNABgeY8YXPl9UST3nhloVRJ+EXzAA8/IZExZEZnTzmlzs QnmroHeWFovLigX0nI0nky8MR9oYGj6V8UxAbmVXVY/te2HxB3r6XECSWc/oMWIkMKJJ4KaUSWOnU L/lWNK16IY0EL1wNVV4+TeJDOosjmFJc6zTzlCBs7OKop73/7cJqgu+YgWZcA3YD/ydwM02s68KfO qjXLtIQpnxM9WOzK8zrG8m0pr1sz6dgNBLEr08YkCMWIiSVo1+v4GI/72JDt8BuhCWob8OE0CGxl2 7MQP3hlw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8Mq6-0001dB-46; Mon, 25 Mar 2019 10:28:22 +0000 Received: from mout.kundenserver.de ([212.227.126.134]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8Mpt-0001Qf-Nj; Mon, 25 Mar 2019 10:28:19 +0000 Received: from [192.168.178.52] ([109.104.40.77]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.167]) with ESMTPSA (Nemesis) id 1MXotA-1hTIxL0bC0-00YAnD; Mon, 25 Mar 2019 11:28:03 +0100 Subject: Re: [PATCH V2 6/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported To: kernel@martin.sperl.org, Mark Brown , Eric Anholt , Hubert Denkmair , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org References: <20190324175002.28969-1-kernel@martin.sperl.org> <20190324175002.28969-7-kernel@martin.sperl.org> From: Stefan Wahren Message-ID: <1e83f4f4-f9ae-2d77-3729-2343a4975e20@i2se.com> Date: Mon, 25 Mar 2019 11:28:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190324175002.28969-7-kernel@martin.sperl.org> Content-Language: en-US X-Provags-ID: V03:K1:tpcd8z/vVrzZSAOUxHA1Q2FM9XDAD4OfJLSBJm6xVamc6R9JAUv jKOIjHgXOeqGRGqHVejflv+tShnqJr2OPrKPxV8xKfYU5OPscHJfa2sQ5226k1dApecvmsZ u+kqUAMepGJhd06y9Sxq3vBQoB6zO19iaQWRVuorJL4v/RbAtLki8Rb/JUlD+Hh7AEjVjco AOVYnDQ3T/WijIvxxWcMg== X-UI-Out-Filterresults: notjunk:1;V03:K0:UihaA4W1NtY=:I7/PlaAINGyk2amHSkbgho OG8gGoihcUPEeyKlwempD6MlqCcFkNdk+i8NCYNIui5Rg0mi2+hFsNzzB7Fx4rzZAVENwWhPd +WnRvS4FBpdyoTq8Ik+63REsDFWoLUVRihRjNWF/+zNvpeNuoRCHiqVjy/VQR1XZXeusizLqD EZLXhej+gczPn72TnxsSJ7c3Wkln3TiE66oHE3JAcses/0X66rl8wNHfqbpKQwoU8BRc/qFB9 lqobS5QrbGVwRjoDKE+asYh29cuwhTlKMYfcXwnMcwCqMb76dgJ3xze6bfcdbPQezBTtDBX8P ZcQbSCoOpCKaXQw9uNPLJfU1y9iuy+8xKRCba0ACItDmtIObBUZd2WpLlFdjUg2u9LNS/747e DaD9b2b0AjQrzvhxF7/4nUl26G+Ya3lp5yY2CZLvRwe35fD/2VSdh3mnLFokEiyYs3CYsdGFl ZRQZGVAQGdPvLh50IWNjMasCrZmusLenbCRF0DjhEWtiXbntdT0zQMRdOOXr71pZ5aoj5NCef Zlg6wTllf9moSq+SUYRZ6SNem1u3r4N1ImJM5RK/f1Q1EAyoSwRni1rvyZhDlpfBRsOhbUWy0 y90eEhyI5G9WOcC36TlOXFDLBoIje2pRbZ7mDg1b6e0a/hKioisThnO+eaSw5c4Y/AYwIiOmP +iZhLPqQ0Gtx9LXyRktjpqOQv+v5RHuByRmfUaSJ8DgFc5Kj6HG4Rv7U4VEX00JaAqnv/g+Xa siW0CQTMhT54od0hGeIptK2bP8IrUwRYav41Cf47KYkceUAxLaSaz8TI+bU= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190325_032810_933447_D91A0371 X-CRM114-Status: GOOD ( 21.62 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Martin, Am 24.03.19 um 18:49 schrieb kernel@martin.sperl.org: > From: Martin Sperl > > From personal bad experience (even as the author of the original driver) > it shows that native-cs is "somewhat" supported by the spi bus driver > when using a buggy device tree. > > So make sure that the driver is warning in dmesg about this fact > that we are running in a not supported mode that may have surprizing > limitations. > > Signed-off-by: Martin Sperl > Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e please use a proper fixes tag. > --- > drivers/spi/spi-bcm2835aux.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c > index c8acde017b6a..6af07dec5fdc 100644 > --- a/drivers/spi/spi-bcm2835aux.c > +++ b/drivers/spi/spi-bcm2835aux.c > @@ -396,6 +396,38 @@ static void bcm2835aux_spi_handle_err(struct spi_master *master, > bcm2835aux_spi_reset_hw(bs); > } > > +static int bcm2835aux_spi_setup(struct spi_device *spi) > +{ > + int ret; > + > + if (spi->mode & SPI_NO_CS) > + return 0; > + /* sanity check for native cs */ > + if (!gpio_is_valid(spi->cs_gpio)) { > + /* for dt-backwards compatibility: only support native on CS0 > + * known things not supported with broken native CS: > + * * multiple chip-selects: cs0-cs2 are all > + * simultaniously asserted whenever there is a transfer > + * this even includes SPI_NO_CS > + * * SPI_CS_HIGH: cs are always asserted low > + * * cs_change: cs is deasserted after each spi_transfer > + * * cs_delay_usec: cs is always deasserted one SCK cycle > + * after the last transfer > + * probably more... > + */ > + if (spi->chip_select == 0) { > + dev_err(&spi->dev, > + "native CS is not supported but may work for some use-cases for cs = 0 - please define a valid value cs-gpios in DT for complete feature set\n"); > + return 0; These messages are rather too long, please keep it in the ~ 80 char limit (in source code and dmesg). Or make it two lines ... Since we return with 0, i prefer to use dev_warn instead of dev_err. Thanks > + } > + dev_err(&spi->dev, > + "native CS is not supported for cs > 0 - please define a valid value cs-gpios in DT to enable multiple cs\n"); > + return -EINVAL; > + } > + > + return 0; > +} > + _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel