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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH 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 B689CC282DD for ; Mon, 10 Jun 2019 10:20:51 +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 8B1B620859 for ; Mon, 10 Jun 2019 10:20:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nd0wB27L"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="xGOZzIJL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B1B620859 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org 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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=d1U2Is+0baZh6FnmYwYilfdOxl11XtzEqovbpowXzDo=; b=nd0wB27LGKGHjB m8ntISSdo5DWCGz1W/zPhQ9GQxXzvDOg4D/DyWOLea4TDgDHC7f56vbrBhQbtWbvX9IrvonpGhGiv cJZdJUVCbsQF7lNgI64ubttDjfM98Z45SS+z8nM+H6Jy8hs7K4uzQ5Ndt8kq0/ryksr8jc90f5IcV sbK1goJnsQXvokadMeVVjAwIi6HyT7p2jXSLU+n59SGcuiK68Da3NX6m7Z5ujoNNVg5Im6feHAMXO HetqPeYdMcUE+bEr8quOCf2Ljeuyej/conTI9DVkprk9xDAoRhV/xUkTa1FNLNItvbshUw3wfP1Hq FhhFXKVXBRA2RNvtHD/Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haHPz-0002h4-MU; Mon, 10 Jun 2019 10:20:47 +0000 Received: from mail-it1-x142.google.com ([2607:f8b0:4864:20::142]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1haHPw-0002gR-Oc for linux-arm-kernel@lists.infradead.org; Mon, 10 Jun 2019 10:20:46 +0000 Received: by mail-it1-x142.google.com with SMTP id i21so12358212ita.5 for ; Mon, 10 Jun 2019 03:20:44 -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=TD9nldu+Dkg66DtJL22FIFPPAtJrtLwLTy4JIGvUcQ0=; b=xGOZzIJLwgDnCGn+KlPHKMf5rhw1h6HPB+95GrnYpcFyME3d6inxxLyUdmnkUq34J+ zIomGN+MLBR/oBWOe0ulrBE7Z4E32pfkipA+UvLZ1HSdKDy8GC6l8Mp9wJ803ogYGbAJ XkKTMgVLsEwE6FpWaaDwbvNxWnbiruke6qUOyB0ejNsZuBRBi3b43yVy4fvDCb91ewO2 Zjef6VagFWfnsI0m34DKo41NNnLdVP9/Dyh1VbdA8PowiwZdyPE/WzmPhq03ic8Wi1/B bsA1uFFW4PNjaH9sgcjjZ0hpbNNQwDPdUAJ2P909ro09PZSJ1gys4wpgtKshS4+ctbrH zTDA== 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=TD9nldu+Dkg66DtJL22FIFPPAtJrtLwLTy4JIGvUcQ0=; b=Ew7s7xjdSXJk47sAwOSW5SRhUdtz+BKwX7iLNM9FpwmbuwM+KpIZK6VEFD80tEha8e vziDurjGGvlpRphnTmx1HA/XQoLcXKtlKxc2oubKnLqnx5yXXkXCfd1JqxyXAquFzzf/ OZxMVMQRIDUZSF8IUynsI9klLvtp8p/x6HNh6MvkvCJe80mYNC5ASfCjKJ3l321z06OU P+npQveCUCQI96U9x8qYNi7mnFB5GtBCvG/Vr5gRzKQFhDa1gEdZewBJxt6BdQtWdUul ZA8Rd/jAFwrOueVzhs9+sLOSP1Z/fDDWEPmfQsqOkvDkNsOzduxMluKmxB9xjPwOgHyi Fh9w== X-Gm-Message-State: APjAAAW/cYxQr4FYiWjpL6vxFos+RFHQYX0YTeqNeBNlLFxINC20bqOb TnrTsTKOFAh5bGk7v9WUDXkiOdA1LMs4PNrXtKAYGw== X-Google-Smtp-Source: APXvYqz8+9gsk4GZjuP3WNO3dIJxKVqLA91XwEqoIRkCKyS++7skP/Y8F+BITEkNQ+1mKDd2q8VehsdTmYGSs98dr0s= X-Received: by 2002:a05:660c:44a:: with SMTP id d10mr12222840itl.153.1560162043688; Mon, 10 Jun 2019 03:20:43 -0700 (PDT) MIME-Version: 1.0 References: <20190610084213.1052-1-lee.jones@linaro.org> <20190610084213.1052-4-lee.jones@linaro.org> <20190610085542.GL4797@dell> <20190610092245.GN4797@dell> In-Reply-To: <20190610092245.GN4797@dell> From: Ard Biesheuvel Date: Mon, 10 Jun 2019 12:20:30 +0200 Message-ID: Subject: Re: [PATCH v3 4/8] pinctrl: qcom: sdm845: Provide ACPI support To: Lee Jones X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190610_032044_804040_D6A73D9F X-CRM114-Status: GOOD ( 25.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: balbi@kernel.org, wsa+renesas@sang-engineering.com, Greg Kroah-Hartman , Linus Walleij , linux-usb , Linux Kernel Mailing List , Bjorn Andersson , David Brown , alokc@codeaurora.org, linux-i2c , "open list:GPIO SUBSYSTEM" , linux-arm-msm , Andy Gross , Jeffrey Hugo , linux-arm-kernel 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 On Mon, 10 Jun 2019 at 11:22, Lee Jones wrote: > > On Mon, 10 Jun 2019, Ard Biesheuvel wrote: > > > On Mon, 10 Jun 2019 at 10:55, Lee Jones wrote: > > > > > > On Mon, 10 Jun 2019, Ard Biesheuvel wrote: > > > > > > > On Mon, 10 Jun 2019 at 10:42, Lee Jones wrote: > > > > > > > > > > This patch provides basic support for booting with ACPI instead > > > > > of the currently supported Device Tree. When doing so there are a > > > > > couple of differences which we need to taken into consideration. > > > > > > > > > > Firstly, the SDM850 ACPI tables omit information pertaining to the > > > > > 4 reserved GPIOs on the platform. If Linux attempts to touch/ > > > > > initialise any of these lines, the firmware will restart the > > > > > platform. > > > > > > > > > > Secondly, when booting with ACPI, it is expected that the firmware > > > > > will set-up things like; Regulators, Clocks, Pin Functions, etc in > > > > > their ideal configuration. Thus, the possible Pin Functions > > > > > available to this platform are not advertised when providing the > > > > > higher GPIOD/Pinctrl APIs with pin information. > > > > > > > > > > Signed-off-by: Lee Jones > > > > > > > > For the ACPI probing boilerplate: > > > > Acked-by: Ard Biesheuvel > > > > > > > > *However*, I really don't like hardcoding reserved GPIOs like this. > > > > What guarantee do we have that each and every ACPI system > > > > incorporating the QCOM0217 device has the exact same list of reserved > > > > GPIOs? > > > > > > This is SDM845 specific, so the chances are reduced. > > > > You don't know that. > > All the evidence I have to hand tells me that this is the case. Even > on very closely related variants Qualcomm uses different H/W blocks > for GPIO. > > > > However, if another SDM845 variant does crop up, also lacking the > > > "gpios" property, we will have to find another differentiating factor > > > between them and conduct some matching. What else can you do with > > > platforms supporting non-complete/non-forthcoming ACPI tables? > > > > > > > Either we don't touch any pins at all if they are not referenced > > explicitly anywhere > > I guess this would require an API change, which is out of scope of > this patch-set. Happy to change this implementation later if the > subsystem allows for it though. > > > or we parse the PEP tables, which seem to cover > > some of this information (if Bjorn's analysis is correct) > > Maybe someone can conduct some further work on this when we start to > enable or write a driver for the PEP (Windows-compatible System Power > Management Controller). The tables for the PEP look pretty complex, > so this task would be extremely difficult if not impossible without > Qualcomm's help. I wouldn't even know how to extrapolate this > information from the tables. > > > (if Bjorn's analysis is correct) > > Bjorn is about to provide his Reviewed-by for this implementation. > If Bjorn can live with it, then so can I. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel