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 A1208C46467 for ; Thu, 19 Jan 2023 11:36:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230449AbjASLg4 (ORCPT ); Thu, 19 Jan 2023 06:36:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230421AbjASLfj (ORCPT ); Thu, 19 Jan 2023 06:35:39 -0500 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4092B83; Thu, 19 Jan 2023 03:35:29 -0800 (PST) Received: from booty (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id A9052E0012; Thu, 19 Jan 2023 11:35:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1674128128; 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=9b4Gd71VIpRzmWAFvIEX9qIOF0R0AhLHNhOUdNP3BeY=; b=dwQEieih0KVf2hhXRvwQq0Dfw9zd0/0j7TapWPquKpkqFdrH1zKD/aKuctuBVhciWWfqMi isuP5qMq4WOLwJ4n0SLcsXDH51ybVlGZfVeKOC2QqqzXs0Dj2eBiXyRmD6czMihTluHhJi r35o/pZRGJooSKyOtcPzL2ucsqvfzHQ120rM4A5gMMyXGO1guHYDp+UsEoBd0N8R4d+KGi XtWhPtJGMvBy+sAc9R4EhQSjcbcLmPlQ4ubJ2ylTLx2FBxMXmCnpU/eovi2ZVBg2/csI35 ecMDVy8a/qHpzX9LBJsiD2jvxhlwoPJJU+JxNGtBio8F0yVjKedBxw+IaGjkKA== Date: Thu, 19 Jan 2023 12:35:20 +0100 From: Luca Ceresoli To: Tomi Valkeinen Cc: Andy Shevchenko , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, Rob Herring , Krzysztof Kozlowski , Wolfram Sang , Matti Vaittinen , Laurent Pinchart , Mauro Carvalho Chehab , Peter Rosin , Liam Girdwood , Mark Brown , Sakari Ailus , Michael Tretter , Shawn Tu , Hans Verkuil , Mike Pagano , Krzysztof =?UTF-8?Q?Ha=C5=82asa?= , Marek Vasut , Luca Ceresoli Subject: Re: [PATCH v7 1/7] i2c: add I2C Address Translator (ATR) support Message-ID: <20230119123520.7f1aa680@booty> In-Reply-To: References: <20230118124031.788940-1-tomi.valkeinen@ideasonboard.com> <20230118124031.788940-2-tomi.valkeinen@ideasonboard.com> <20230118181753.7a325953@booty> <20230119092115.02cbbab3@booty> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tomi, Andy, On Thu, 19 Jan 2023 12:09:57 +0200 Tomi Valkeinen wrote: > On 19/01/2023 10:21, Luca Ceresoli wrote: > > > > >>>>> +void i2c_atr_set_driver_data(struct i2c_atr *atr, void *data) > >>>>> +{ > >>>>> + atr->priv = data; > >>>>> +} > >>>>> +EXPORT_SYMBOL_NS_GPL(i2c_atr_set_driver_data, I2C_ATR); > >>>>> + > >>>>> +void *i2c_atr_get_driver_data(struct i2c_atr *atr) > >>>>> +{ > >>>>> + return atr->priv; > >>>>> +} > >>>>> +EXPORT_SYMBOL_NS_GPL(i2c_atr_get_driver_data, I2C_ATR); > >>>> > >>>> Just to be sure: Is it really _driver_ data and not _device instance_ data? > >>> > >>> It is device instance data indeed. I don't remember why this got > >>> changed, but in v3 it was i2c_atr_set_clientdata(). > >> > >> It's me who was and is against calling it clientdata due to possible > >> confusion with i2c_set/get_clientdata() that is about *driver data*. > >> I missed that time the fact that this is about device instance data. > >> I dunno which name would be better in this case, i2c_atr_set/get_client_priv() ? > > > > Not sure I'm following you here. The i2c_atr_set_clientdata() name was > > given for similarity with i2c_set_clientdata(). The latter wraps > > dev_set_drvdata(), which sets `struct device`->driver_data. There is > > one driver_data per each `struct device` instance, not per each driver. > > The same goes for i2c_atr_set_driver_data(): there is one priv pointer > > per each `struct i2c_atr` instance. > > I'm a bit confused. What is "driver data" and what is "device instance > data"? > > This deals with the driver's private data, where the "driver" is the > owner/creator of the i2c-atr. The i2c-atr itself doesn't have a device > (it's kind of part of the owner's device), and there's no driver in > i2c-atr.c > > I don't like "client" here, as it reminds me of i2c_client (especially > as we're in i2c context). > > What about i2c_atr_set_user_data()? Or "owner_data"? Ah, only now I got the point Andy made initially about "client" not being an appropriate word. In i2c we have: i2c_set_clientdata(struct i2c_client *client, void *data) ^^^^^^~~~~ ^^^^^^ ~~~~ so "client" clearly makes sense there, now here. The same logic applied here would lead to: i2c_atr_set_atrdata(struct i2c_atr *atr, void *data) ^^^~~~~ ^^^ ~~~~ which makes sense but it is a ugly IMO. So I think i2c_atr_get_driver_data() in this v7 makes sense, it's to set the data that the ATR driver instance needs. This is coherent with logic in spi/spi.h: spi_set_drvdata(struct spi_device *spi, void *data) except for the abbreviation ("_drvdata" vs "_driver_data"). Andy, Tomi, would i2c_atr_set_drvdata() be OK for you, just like SPI does? -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com