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,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 157FEC4338F for ; Fri, 20 Aug 2021 13:08:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EEA0361053 for ; Fri, 20 Aug 2021 13:08:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238220AbhHTNJL (ORCPT ); Fri, 20 Aug 2021 09:09:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240719AbhHTNJL (ORCPT ); Fri, 20 Aug 2021 09:09:11 -0400 Received: from mail-qt1-x832.google.com (mail-qt1-x832.google.com [IPv6:2607:f8b0:4864:20::832]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92C64C061756 for ; Fri, 20 Aug 2021 06:08:33 -0700 (PDT) Received: by mail-qt1-x832.google.com with SMTP id e3so1198234qth.9 for ; Fri, 20 Aug 2021 06:08:33 -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:content-transfer-encoding; bh=TUaFXYR3HgX7rq/VVrgPte+1/jUiDRhyGavFeUWW8ns=; b=qyykdYkmfS+sozWV6prsKemkogSdt6dw3JI6xplGBEyTZrCLVw/V2WrXps+vMYETkc 8Te8E/naVt9sCYftHN+RQWgeipXTUxRrtvWgldkYCu2Cbe9g6ADwtRoynUE5z+qBzTjG 54yO9pPGaOTEYQUVc1FEW/T8RQKm7EsP8D7GtvNgk4bFWoxEOLRtHkxavfl9A0+APfke fUSP5CH+beQOqMRPOpWAxyXQpPSp8NBKx7ZcRxpsbapjzzBlp12z8K73a7u/zLR3Yi/5 /eO+ssNjqZxgkZLIbtO1QrlN47VLwXpLqfNwD+gSTbQel6v8qOEG9qHA3WYS7WzopQpP XncQ== 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:content-transfer-encoding; bh=TUaFXYR3HgX7rq/VVrgPte+1/jUiDRhyGavFeUWW8ns=; b=fz9c9X0mQgAxH08iV38Ll36PBj12AQe01CwwinCaln0+hglNfenSXxFL1FGvWTAVl/ Q+O6eWartbGvileYIIVAi8R0NZpVVPgibJ5Uxw7t8eIoYt3bB5k1FErTKsh6jEn46+NR caegUPOJMGHB7d16zOo9lLB/+PFjYcvKTm5CdItlBvkRncTkhttM7ImOS/e0XV6ZEW6N NNyDMvew3lBULC6Pf9UIQKwz6XTABV+3qTZOTCLA5u3v35LYK6q+xbIru+uVnXrOR6f4 3aZNVcOLl4e4vBQApatoUTOd0I7ACNC2s8F7pt7gyrVgDYKW6mlrMtkv+cdXO6gCXhCB 9XyA== X-Gm-Message-State: AOAM533KTlXVtiDqZCJQR+Tt7xtHUaL7QrCo0El19zglozte/DaH94AG VSFW0oKIJ10m7136ChUSIQec5TZJbra1C/Kd2rY9qg== X-Google-Smtp-Source: ABdhPJyHXvzqFdkh92xFSl2Tfgr6Wq+GnxyuqFmSQJ3g0FPjwxN9S26JOc0IArVq879EP1YIZ1goBTULRA693ce45J8= X-Received: by 2002:a05:622a:13c8:: with SMTP id p8mr17705841qtk.238.1629464912762; Fri, 20 Aug 2021 06:08:32 -0700 (PDT) MIME-Version: 1.0 References: <20210817005507.1507580-1-dmitry.baryshkov@linaro.org> <1CA665D1-86F0-45A1-862D-17DAB3ABA974@holtmann.org> In-Reply-To: <1CA665D1-86F0-45A1-862D-17DAB3ABA974@holtmann.org> From: Dmitry Baryshkov Date: Fri, 20 Aug 2021 16:08:21 +0300 Message-ID: Subject: Re: [RFC PATCH 00/15] create power sequencing subsystem To: Marcel Holtmann Cc: Andy Gross , Bjorn Andersson , Ulf Hansson , Johan Hedberg , Luiz Augusto von Dentz , Kalle Valo , "David S. Miller" , Jakub Kicinski , Stanimir Varbanov , MSM , linux-mmc@vger.kernel.org, open list , "open list:BLUETOOTH SUBSYSTEM" , ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On Thu, 19 Aug 2021 at 18:23, Marcel Holtmann wrote: > > This is an RFC of the proposed power sequencer subsystem. This is a > > generification of the MMC pwrseq code. The subsystem tries to abstract > > the idea of complex power-up/power-down/reset of the devices. > > > > The primary set of devices that promted me to create this patchset is > > the Qualcomm BT+WiFi family of chips. They reside on serial+platform > > interfaces (older generations) or on serial+PCIe (newer generations). > > They require a set of external voltage regulators to be powered on and > > (some of them) have separate WiFi and Bluetooth enable GPIOs. > > > > This patchset being an RFC tries to demonstrate the approach, design an= d > > usage of the pwrseq subsystem. Following issues are present in the RFC > > at this moment but will be fixed later if the overall approach would be > > viewed as acceptable: > > > > - No documentation > > While the code tries to be self-documenting proper documentation > > would be required. > > > > - Minimal device tree bindings changes > > There are no proper updates for the DT bindings (thus neither Rob > > Herring nor devicetree are included in the To/Cc lists). The dt > > schema changes would be a part of v1. > > > > - Lack of proper PCIe integration > > At this moment support for PCIe is hacked up to be able to test the > > PCIe part of qca6390. Proper PCIe support would require automatically > > powering up the devices before the scan basing on the proper device > > structure in the device tree. > > > > ---------------------------------------------------------------- > > Dmitry Baryshkov (15): > > power: add power sequencer subsystem > > pwrseq: port MMC's pwrseq drivers to new pwrseq subsystem > > mmc: core: switch to new pwrseq subsystem > > ath10k: add support for pwrseq sequencing > > Bluetooth: hci_qca: merge qca_power into qca_serdev > > Bluetooth: hci_qca: merge init paths > > Bluetooth: hci_qca: merge qca_power_on with qca_regulators_init > > Bluetooth: hci_qca: futher rework of power on/off handling > > Bluetooth: hci_qca: add support for pwrseq > > any chance you can try to abandon patching hci_qca. The serdev support in= hci_uart is rather hacking into old line discipline code and it is not agi= ng well. It is really becoming a mess. I wanted to stay away from rewriting the BT code. But... New driver would have a bonus point that I don't have to be compatible with old bindings. In fact we can even make it the other way around: let the old driver always use regulators and make the new driver support only the pwrseq. Then it should be possible to drop the old hci_qca driver together with dropping the old bindings. > I would say that the Qualcomm serial devices could use a separate standal= one serdev driver. A while I send an RFC for a new serdev driver. > > https://www.spinics.net/lists/linux-bluetooth/msg74918.html Any reason why your driver stayed as an RFC and never made it into the kernel? Do you plan to revive your old RFCs on H:4 and H:5? > There I had the idea that simple vendor specifics can be in that driver (= like the Broadcom part I added there), but frankly the QCA specifics are a = bit too specific and it should be a separate driver. However I think this w= ould be a good starting point. > > In general a H:4 based Bluetooth driver is dead simple with the help of h= 4_recv.h helper we have in the kernel. The complicated part is the power ma= nagement pieces or any vendor specific low-power protocol they are running = on that serial line. And since you are touching this anyway, doing a driver= from scratch might be lot simpler and cleaner. It would surely help all th= e new QCA device showing up in the future. --=20 With best wishes Dmitry