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=-6.0 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,URIBL_BLOCKED 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 9E015C07E96 for ; Thu, 8 Jul 2021 11:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78CB461436 for ; Thu, 8 Jul 2021 11:37:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231696AbhGHLki (ORCPT ); Thu, 8 Jul 2021 07:40:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231575AbhGHLki (ORCPT ); Thu, 8 Jul 2021 07:40:38 -0400 Received: from mail-qk1-x72a.google.com (mail-qk1-x72a.google.com [IPv6:2607:f8b0:4864:20::72a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C3FCC061760 for ; Thu, 8 Jul 2021 04:37:56 -0700 (PDT) Received: by mail-qk1-x72a.google.com with SMTP id q190so5303973qkd.2 for ; Thu, 08 Jul 2021 04:37:56 -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=N/qY52HtEnySw8oiOqnCY6Vr04Y1zPZsw52TSvRcqL0=; b=X3Au6Pi/gZuIKEizEtZpkpNYlgIbyi0G/awOjci961zqy8EYfCIrI09IB45E8MZzkn 7AVSU1L4UzvADeoHy3cJPWyN+BKIqrka7aQLlq0dTLu0v8Bd4yKSpQyb3T6Vsjf1cqC9 pbP9wWK6juYmhotjALZkdmH+dl8zKezlghv4zvCXvk0FunQYEervgRw4wCYkBksuC557 JGt2vEAgIUA5PDhK0O0Fhmslq7U4Av3gNG21p9JwL0p0HFzVXt93DVGB8IfThBaAfAFA N49Jy+lJPz3i9tWnQoQk+O0Zv5Y8rD1iMixULgWhqGkhJInmouQgldcAyfIqcTqB44ID 9UbA== 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=N/qY52HtEnySw8oiOqnCY6Vr04Y1zPZsw52TSvRcqL0=; b=mp3uVbHk3aGmSvfWZUrcyXnNQqnUz3h7/fupiNj9gFfFjlZPhalFg08wMg9E3LY6Id oy9G6ltefsYG01rsdXbdvT6zhZjZL0Kn44b7N4Au5zgGgjvZZ3vxqdSpygk3V1n2kg3X CD+2lDxHWgsLiUWU6lW8QNb/U/Hp90Eu9lssyGNawKyZPtGDyQhDuM2MsR/rhHxF9khG 1Gfp27bp3eNdiGtoeqxSnqbI4OzKK56isCyVqtT3QAFuc9HRT5vuWdRVf7yLpdmNoKRV Okg8ltMWzFdbiD/rBZTkIsyikR+Cn25P0r8Td9i6yFVYNpk2Pal9ys7qMMAEyUzQjAaP TxNQ== X-Gm-Message-State: AOAM530gK0Giyo8c/35YPl2M6dNL3nJYpQdB9Q4BJAi3Ou+7AJYhcU8D YP4zgeZcLTn0P8ThDAKL0bUEFq22Y3/TJYzjahaFQA== X-Google-Smtp-Source: ABdhPJzLaw+Ocua2+xY6AepEwv2jQPUmOKbSjrNWV4ZgDNgxv4FrDkLyxft2BVw+2yuajvOMGGJpZ4Sga0z4xviKWRM= X-Received: by 2002:a05:620a:13ec:: with SMTP id h12mr14862220qkl.217.1625744275692; Thu, 08 Jul 2021 04:37:55 -0700 (PDT) MIME-Version: 1.0 References: <20210621223141.1638189-1-dmitry.baryshkov@linaro.org> <20210621223141.1638189-3-dmitry.baryshkov@linaro.org> <20210706115517.GB4529@sirena.org.uk> In-Reply-To: From: Dmitry Baryshkov Date: Thu, 8 Jul 2021 14:37:44 +0300 Message-ID: Subject: Re: [PATCH v3 2/7] regulator: qca6390: add support for QCA639x powerup sequence To: Ulf Hansson , Peter Chen Cc: Mark Brown , Andy Gross , Bjorn Andersson , Rob Herring , Liam Girdwood , Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , linux-arm-msm , Manivannan Sadhasivam , DTML , Linux Kernel Mailing List , linux-bluetooth@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi, On Thu, 8 Jul 2021 at 13:10, Ulf Hansson wrote: > > - Peter (the email was bouncing) + Peter's kernel.org address > > On Tue, 6 Jul 2021 at 13:55, Mark Brown wrote: > > > > On Tue, Jul 06, 2021 at 09:54:03AM +0200, Ulf Hansson wrote: > > > On Tue, 22 Jun 2021 at 00:32, Dmitry Baryshkov > > > > > > Qualcomm QCA6390/1 is a family of WiFi + Bluetooth SoCs, with BT part > > > > being controlled through the UART and WiFi being present on PCIe > > > > bus. Both blocks share common power sources. Add device driver handling > > > > power sequencing of QCA6390/1. > > > > > Power sequencing of discoverable buses have been discussed several > > > times before at LKML. The last attempt [1] I am aware of, was in 2017 > > > from Peter Chen. I don't think there is a common solution, yet. > > > > This feels a bit different to the power sequencing problem - it's not > > exposing the individual inputs to the device but rather is a block that > > manages everything but needs a bit of a kick to get things going (I'd > > guess that with ACPI it'd be triggered via AML). It's in the same space > > but it's not quite the same issue I think, something that can handle > > control of the individual resources might still struggle with this. > > Well, to me it looks very similar to those resouses we could manage > with the mmc pwrseq, for SDIO. It's also typically the same kind of > combo-chips that moved from supporting SDIO to PCIe, for improved > performance I guess. More importantly, the same constraint to > pre-power on the device is needed to allow it to be discovered/probed. In our case we'd definitely use pwrseq for PCIe bus and we can also benefit from using pwrseq for serdev and for platform busses also (for the same story of WiFi+BT chips). I can take a look at rewriting pwrseq code to also handle the PCIe bus. Rewriting it to be a generic lib seems like an easy task, plugging it into PCIe code would be more fun. Platform and serdev... Definitely even more fun. > Therefore, I think it would be worth having a common solution for > this, rather than a solution per subsystem or even worse, per device. > > Unfortunately, it looks like Peter's email is bouncing so we can't get > an update from him. Let's see if the kernel.org email will get to him. -- With best wishes Dmitry