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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 20455C433EB for ; Tue, 28 Jul 2020 08:27:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE4D52075D for ; Tue, 28 Jul 2020 08:27:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=walle.cc header.i=@walle.cc header.b="S7DRFmHq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728064AbgG1I1O (ORCPT ); Tue, 28 Jul 2020 04:27:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727975AbgG1I1O (ORCPT ); Tue, 28 Jul 2020 04:27:14 -0400 Received: from ssl.serverraum.org (ssl.serverraum.org [IPv6:2a01:4f8:151:8464::1:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7E65C061794; Tue, 28 Jul 2020 01:27:13 -0700 (PDT) Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id BABB022FEB; Tue, 28 Jul 2020 10:27:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1595924832; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JGvmLpKj0ffDloszsViH51AGCWvtowTnXfF4m9p9DV4=; b=S7DRFmHqAOU4Aw0NYgpfjw2EwxtpDc+xcMvnw1SLY9z6TFskN0zmgh0siOklM9wv9T/KB6 D6kMjXefyUR2FBBy95WnBCWEK+I3+iFsebjr+F74Loiw56yyTRivb6WSHHd2SCtZipzg/B l3VEVUks9QZVgKwOTuTD7nYV2Y9GIz8= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 28 Jul 2020 10:27:11 +0200 From: Michael Walle To: Lee Jones Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-pwm@vger.kernel.org, linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Linus Walleij , Bartosz Golaszewski , Rob Herring , Jean Delvare , Guenter Roeck , Thierry Reding , =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?= , Wim Van Sebroeck , Shawn Guo , Li Yang , Thomas Gleixner , Jason Cooper , Marc Zyngier , Mark Brown , Greg Kroah-Hartman , Andy Shevchenko , Catalin Marinas , Will Deacon , Pavel Machek Subject: Re: [PATCH v6 01/13] mfd: add simple regmap based I2C driver In-Reply-To: <20200728081506.GA2419169@dell> References: <20200725231834.25642-1-michael@walle.cc> <20200725231834.25642-2-michael@walle.cc> <20200728071949.GE1850026@dell> <23a9ecf5fe4f15b9b20a91cc292aca80@walle.cc> <20200728081506.GA2419169@dell> User-Agent: Roundcube Webmail/1.4.7 Message-ID: <5de219e973e9d3c1455f1a09b4ce4177@walle.cc> X-Sender: michael@walle.cc Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Am 2020-07-28 10:15, schrieb Lee Jones: > On Tue, 28 Jul 2020, Michael Walle wrote: > >> Am 2020-07-28 09:19, schrieb Lee Jones: >> > On Sun, 26 Jul 2020, Michael Walle wrote: >> > >> > > There are I2C devices which contain several different functions but >> > > doesn't require any special access functions. For these kind of >> > > drivers >> > > an I2C regmap should be enough. >> > > >> > > Create an I2C driver which creates an I2C regmap and enumerates its >> > > children. If a device wants to use this as its MFD core driver, it has >> > > to add an individual compatible string. It may provide its own regmap >> > > configuration. >> > > >> > > Subdevices can use dev_get_regmap() on the parent to get their regmap >> > > instance. >> > > >> > > Signed-off-by: Michael Walle >> > > --- >> > > Changes since v5: >> > > - removed "select MFD_CORE" in Kconfig >> > > - removed help text in Kconfig, we assume that the users of this >> > >> > That's the opposite of what I asked for. >> >> What is the use to describe the symbol, if it is not user selectable? >> I'm not aware this is done anywhere in the kernel, am I missing >> something? > > You mean in menuconfig? > > I find 'help's helpful even outside of menuconfig. > > Surely I'm not the only one who reads them 'raw'? Its already available in the header of the file. But sure, I can copy it. >> > > driver will have a "select MFD_SIMPLE_MFD_I2C". Instead added >> > > a small description to the driver itself. >> > > - removed "struct simple_mfd_i2c_config" and use regmap_config >> > > directly >> > > - changed builtin_i2c_driver() to module_i2c_driver(), added >> > > MODULE_ boilerplate >> > > - cleaned up the included files >> > > >> > > Changes since v4: >> > > - new patch. Lee, please bear with me. I didn't want to delay the >> > > new version (where a lot of remarks on the other patches were >> > > addressed) even more, just because we haven't figured out how >> > > to deal with the MFD part. So for now, I've included this one. >> > > >> > > drivers/mfd/Kconfig | 5 ++++ >> > > drivers/mfd/Makefile | 1 + >> > > drivers/mfd/simple-mfd-i2c.c | 55 >> > > ++++++++++++++++++++++++++++++++++++ >> > > 3 files changed, 61 insertions(+) >> > > create mode 100644 drivers/mfd/simple-mfd-i2c.c >> > > >> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig >> > > index 33df0837ab41..c08539c7a166 100644 >> > > --- a/drivers/mfd/Kconfig >> > > +++ b/drivers/mfd/Kconfig >> > > @@ -1162,6 +1162,11 @@ config MFD_SI476X_CORE >> > > To compile this driver as a module, choose M here: the >> > > module will be called si476x-core. >> > > >> > > +config MFD_SIMPLE_MFD_I2C >> > > + tristate >> > > + depends on I2C >> > > + select REGMAP_I2C >> > >> > Please provide a full help. >> >> See above. >> >> > >> > > config MFD_SM501 >> > > tristate "Silicon Motion SM501" >> > > depends on HAS_DMA >> > > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile >> > > index a60e5f835283..78d24a3e7c9e 100644 >> > > --- a/drivers/mfd/Makefile >> > > +++ b/drivers/mfd/Makefile >> > > @@ -264,3 +264,4 @@ obj-$(CONFIG_MFD_STMFX) += stmfx.o >> > > obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o >> > > >> > > obj-$(CONFIG_SGI_MFD_IOC3) += ioc3.o >> > > +obj-$(CONFIG_MFD_SIMPLE_MFD_I2C) += simple-mfd-i2c.o >> > > diff --git a/drivers/mfd/simple-mfd-i2c.c >> > > b/drivers/mfd/simple-mfd-i2c.c >> > > new file mode 100644 >> > > index 000000000000..45090ddad104 >> > > --- /dev/null >> > > +++ b/drivers/mfd/simple-mfd-i2c.c >> > > @@ -0,0 +1,55 @@ >> > > +// SPDX-License-Identifier: GPL-2.0-only >> > > +/* >> > > + * A very simple I2C MFD driver >> > >> > Simple MFD - I2C >> >> ok. >> >> > > + * The driver enumerates its children and registers a common >> > > regmap. Use >> > > + * dev_get_regmap(pdev->dev.parent, NULL) in the child nodes to >> > > fetch that >> > > + * regmap instance. >> > >> > This driver creates a single register map with the intention for it to >> > be shared by all sub-devices. Children can use their parent's device >> > structure (dev.parent) in order reference it. >> >> Should this be appended or should it replace my paragraph? If its the >> latter, >> the "enumeration of the children" is missing. > > If you want to keep that part, try: > > This driver creates a single register map with the intention for it to > be shared by all sub-devices. Children can use their parent's device > structure (dev.parent) in order reference it. > > Once the register map has been successfully initialised, any > sub-devices represented by child nodes in Device Tree will be > subsequently registered. > >> > > + * In the future this driver might be extended to support also >> > > other interfaces >> > > + * like SPI etc. >> > >> > Remove this please. >> >> Why would you remove information about the intention of this driver? >> If >> someone >> looks for a place to implement its SPI/I3C/Slimbus MFD driver this >> might >> come >> in handy. > > By all means put something similar in the commit log, but it has no > place in the driver itself. Besides, if we were to add support for > SPI, it is likely to be a completely separate/unrelated driver. Why would that be another driver? It would be 90% copy paste with regmap_init_i2c() replaced by regmap_init_spi() and i2c_driver replaced by spi_driver. But I don't care. I'll remove it. -michael