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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 73E40C4320E for ; Sun, 29 Aug 2021 21:09:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E00B60F51 for ; Sun, 29 Aug 2021 21:09:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236053AbhH2VK0 (ORCPT ); Sun, 29 Aug 2021 17:10:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236019AbhH2VKZ (ORCPT ); Sun, 29 Aug 2021 17:10:25 -0400 Received: from mail-lj1-x22e.google.com (mail-lj1-x22e.google.com [IPv6:2a00:1450:4864:20::22e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0847DC061575 for ; Sun, 29 Aug 2021 14:09:32 -0700 (PDT) Received: by mail-lj1-x22e.google.com with SMTP id c12so22394302ljr.5 for ; Sun, 29 Aug 2021 14:09:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BxGuGUCOWFryUZD+MaZ59To0anU+4+sFudo5C46Dub0=; b=nfV4aILK8Dhh0ahV+TeoNvDhnE+SFerHJVlQxUxDjik6lEG0UgGuflyvtwuZM3YQdm 4qQpuazJBdWnkrpt4pxqeGR2ZFUjui1ttQiGi0NSY0EcDZ4jZ3R/AQRXWUCIgJP7OVwK O45bi3/RbDPtmOwEU4zDvmLxZdYW0R+TNFfnmNx1w2z0ehUmRJXYhtjzBs7s/KsczncH QkM250uLLIMG0o3c+ZFspIKI8WbWDbWAIYHmTNRLyNh6FDls+xLNU4mhI437adrXa7+e IlBSD8RjKAm0Uyce5YAKTJcXYTWGPHLc5TE08oh4vmz/ETInqZxez23f0cGw8+TXNDTo OS0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BxGuGUCOWFryUZD+MaZ59To0anU+4+sFudo5C46Dub0=; b=ONQQT2HKI046/VK5SmyTqTK8J1dhy84U0Yp3UzAl2UeP9Z8ObBU43G9EuHv+eIa3De 8Y04H1ZS+VDbDnDQtE3ODYfhZQZw+oPSOrXX54wMJSnZftvm3fbYi9VZULmVnF/QcIbM fNwe3LFJtENWuynKNEbbVL8nUDOOrr5qLzSbPpsBwhIPFftnZvwOvAQKlRld1m9AufnT ToqIE8zA53AoS5+xbuh2eGKAJz6jNdjthew9L9hHlaVgU5Nit4O5ufT3j1Ofy8MdG3vo qDoeX5wAZhomNLxl5scJIE0T+mdaBDDB3Iqxlkispiwxq1cuPB7IVpVUeWcMqp/qdZqX eJKg== X-Gm-Message-State: AOAM533F+jknB4V+7C2WESkt+XmriUZahmKg1bp5kMgWWANjA2TW2Hmd 6OV86+zfv3WxKFAV5FMb9ISOBqH77r64V82cgEUqxQ== X-Google-Smtp-Source: ABdhPJyLBGZC3w/XZYPqVgq7E9XJqzge4fnt3b3JacxNwyWo1sRegJwGgEN+8tVF7EFU69+xMuu7WMDdF20ZdQXFkk0= X-Received: by 2002:a2e:54f:: with SMTP id 76mr17978352ljf.326.1630271370403; Sun, 29 Aug 2021 14:09:30 -0700 (PDT) MIME-Version: 1.0 References: <20210304034141.7062-1-brad@pensando.io> <20210304034141.7062-2-brad@pensando.io> <20210304091025.ny52qjm7wbfvmjgl@mobilestation> In-Reply-To: From: Linus Walleij Date: Sun, 29 Aug 2021 23:09:19 +0200 Message-ID: Subject: Re: [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control To: Brad Larson , Mark Brown , Serge Semin Cc: Linux ARM , Arnd Bergmann , Bartosz Golaszewski , Adrian Hunter , Ulf Hansson , Olof Johansson , "open list:GPIO SUBSYSTEM" , linux-spi , linux-mmc , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Mon, Aug 23, 2021 at 3:06 AM Brad Larson wrote: > The gpio pins being used for the Elba SoC SPI CS are dedicated to this > function. Are you recommending that the code in > drivers/gpio/gpio-elba-spics.c be integrated into > drivers/spi/spi-dw-mmio.c? That makes most sense does it not? Special purpose pins should be managed by that special purpose hardware driver, DW SPI in this case. The compatible string etc should be enough to determine that we need some extra GPIO control here, possibly specify extra registers for the SPI host etc. The struct spi_master has a special callback .set_cs() and you should make this behave special for your special hardware. In the case of the DW driver it appears that even subdrivers can pass a custom version of this call in struct dw_spi. Yours, Linus Walleij 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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 4B7F9C4320E for ; Sun, 29 Aug 2021 21:11:31 +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 1378660F39 for ; Sun, 29 Aug 2021 21:11:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1378660F39 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Aug 23, 2021 at 3:06 AM Brad Larson wrote: > The gpio pins being used for the Elba SoC SPI CS are dedicated to this > function. Are you recommending that the code in > drivers/gpio/gpio-elba-spics.c be integrated into > drivers/spi/spi-dw-mmio.c? That makes most sense does it not? Special purpose pins should be managed by that special purpose hardware driver, DW SPI in this case. The compatible string etc should be enough to determine that we need some extra GPIO control here, possibly specify extra registers for the SPI host etc. The struct spi_master has a special callback .set_cs() and you should make this behave special for your special hardware. In the case of the DW driver it appears that even subdrivers can pass a custom version of this call in struct dw_spi. Yours, Linus Walleij _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel