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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED0EAC433FE for ; Wed, 29 Dec 2021 20:12:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231787AbhL2UMt (ORCPT ); Wed, 29 Dec 2021 15:12:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231758AbhL2UMs (ORCPT ); Wed, 29 Dec 2021 15:12:48 -0500 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49ED7C061574 for ; Wed, 29 Dec 2021 12:12:48 -0800 (PST) Received: by mail-wr1-x433.google.com with SMTP id k18so9701589wrg.11 for ; Wed, 29 Dec 2021 12:12:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=n8krvMOUPEK6F0o+N9+XFosmRDgMxP8QBHCs3kla8RI=; b=IC55bGUOP7ZwPBye4DspVIQhb7jnifJNc6BUf+60ovYN536DYgrUoQJNAp5410jb/4 e/ks53xs822USd9st6cR77JrMKZxO5J6/oHfsVL4P4E+D+F7wD9r91+tT5uwIIQKf9rj KvM7dfOXxKIikyOcOV3f1WtaYMqJGwBl9mV9OH5qhrJXoi8qfN+JZQiyEl80P4rZWFfS 6ogr2fgBAd26OWTKlfr/k2uUyxdhRsAS4dQGoG54aoa6U+wbvfskVs3NIPQzWjSvlc5L g1afh6Dme2yrInsdibLTo/P+Einq4ADBJgMIQIkSHsgpr06x6LxydSQ+qzIKPZ3yeMYs /vYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=n8krvMOUPEK6F0o+N9+XFosmRDgMxP8QBHCs3kla8RI=; b=KDrvT1abISXLlW4dX77CEHhPiEQ1vEEwMJBrDuecaHUSW+JE33sJi0qO+fWNA/B3vP fuFZ2qLLVReAWuagUyO6pqM4iG5Y2k702xopcyeQqMUgW60Ip8Sd3WkkN4J7Q4v+lRDd bFzqU2B/JaVAVtbgBof7/9rRWKY7GFL970aBrhTO4fqEI4gswt/sW6Gkar898fbi+MeV ++axYzOdoOGrv2dVOz7ns/4xnTPFVxqDt5JgzIizAvAe3NhHMkvfjR6S7p7YRubTHj73 k1kesi6kU9wBUjqjfLeCaqIGLdEn0FtqDlXvFKk36tV5lY5s1Vh0QkIrbTVKLGJe64rN KXJQ== X-Gm-Message-State: AOAM533GkOe2x5HE8LVZleHoi/7DBuf5f98lkORgX8ftjXzZuvDvyO4T X1lNdT1/KdmErfwP96KPzcNx4g== X-Google-Smtp-Source: ABdhPJy1yOGQ3+RzhnmTKk1jgmLANfR6jpUQUpuuGNa9PKHTT1y4KLRkmer2xcdLOcLWqLSwp2IsXg== X-Received: by 2002:adf:e844:: with SMTP id d4mr21464307wrn.151.1640808766838; Wed, 29 Dec 2021 12:12:46 -0800 (PST) Received: from google.com ([2.31.167.18]) by smtp.gmail.com with ESMTPSA id l12sm27352493wmq.2.2021.12.29.12.12.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Dec 2021 12:12:46 -0800 (PST) Date: Wed, 29 Dec 2021 20:12:39 +0000 From: Lee Jones To: Alexandre Belloni Cc: Colin Foster , linux-gpio@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij , Russell King , Heiner Kallweit , Jakub Kicinski , "David S. Miller" , Florian Fainelli , Vivien Didelot , Andrew Lunn , UNGLinuxDriver@microchip.com, Claudiu Manoil , Vladimir Oltean , clement.leger@bootlin.com Subject: Re: [RFC v5 net-next 02/13] mfd: ocelot: offer an interface for MFD children to get regmaps Message-ID: References: <20211218214954.109755-1-colin.foster@in-advantage.com> <20211218214954.109755-3-colin.foster@in-advantage.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > This is almost certainly not the right way to do whatever it is you're > > trying to do! > > > > Please don't try to upstream "somewhat a hack"s into the Mainline > > kernel. > > > > Please elaborate on the correct way to do that. What we have here is a > SoC (vsc7514) that has MMIO devices. This SoC has a MIPS CPU and > everything is fine when using it. However, the CPU can be disabled and > the SoC connected to another CPU using SPI or PCIe. What Colin is doing > here is using this SoC over SPI. Don't tell me this is not an MFD When did anyone say that? > because this is exactly what this is, a single chip with a collection of > devices that are also available separately. > > The various drivers for the VSC7514 have been written using regmap > exactly for this use case. The missing piece is probing the devices over > SPI instead of MMIO. > > Notice that all of that gets worse when using PCIe on architectures that > don't have device tree support and Clément will submit multiple series > trying to fix that. Okay, it sounds like I'm missing some information, let's see if we can get to the bottom of this so that I can provide some informed guidance. > On 29/12/2021 15:23:59+0000, Lee Jones wrote: > > On Sat, 18 Dec 2021, Colin Foster wrote: > > > > > Child devices need to get a regmap from a resource struct, > > > specifically from the MFD parent. Child devices usually fetch the Regmap from a pointer the parent provides. Usually via either 'driver_data' or 'platform_data'. However, we can't do that here because ... > > > The MFD parent has the interface to the hardware > > > layer, which could be I2C, SPI, PCIe, etc. > > > > > > This is somewhat a hack... ideally child devices would interface with the > > > struct device* directly, by way of a function like > > > devm_get_regmap_from_resource which would be akin to > > > devm_get_and_ioremap_resource. However, we can't do that here because ... > > > A less ideal option would be to interface > > > directly with MFD to get a regmap from the parent. > > > > > > This solution is even less ideal than both of the two suggestions, so is > > > intentionally left in a separate commit after the initial MFD addition. > > > > > > Signed-off-by: Colin Foster > > > --- > > > drivers/mfd/ocelot-core.c | 9 +++++++++ > > > include/soc/mscc/ocelot.h | 12 ++++++++++++ > > > 2 files changed, 21 insertions(+) > > > > > > diff --git a/drivers/mfd/ocelot-core.c b/drivers/mfd/ocelot-core.c > > > index a65619a8190b..09132ea52760 100644 > > > --- a/drivers/mfd/ocelot-core.c > > > +++ b/drivers/mfd/ocelot-core.c > > > @@ -94,6 +94,15 @@ static struct regmap *ocelot_mfd_regmap_init(struct ocelot_mfd_core *core, > > > return regmap; > > > } > > > > > > +struct regmap *ocelot_mfd_get_regmap_from_resource(struct device *dev, > > > + const struct resource *res) > > > +{ > > > + struct ocelot_mfd_core *core = dev_get_drvdata(dev); > > > + > > > + return ocelot_mfd_regmap_init(core, res); > > > +} > > > +EXPORT_SYMBOL(ocelot_mfd_get_regmap_from_resource); > > > -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog