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 B024EC001B2 for ; Sun, 11 Dec 2022 16:55:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230164AbiLKQzr (ORCPT ); Sun, 11 Dec 2022 11:55:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230014AbiLKQzq (ORCPT ); Sun, 11 Dec 2022 11:55:46 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AA7BAE73; Sun, 11 Dec 2022 08:55:44 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 73E2A6CF; Sun, 11 Dec 2022 17:55:41 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1670777741; bh=LDWOw2Sq4MMvUwwej0eOVEDdbPyRwLKB+gzMBo56Qj4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vUoExSChEqnDa4coecD0xRZOS1LhwMtXyrNsuCa2Z7Kmj/JFjJQrDmy/ix474Hw6b rthJC7QYuf/F2VBxUeR4sCGQTnKmm4LK0M/gEyABOxQ2LpbcGuPxxU+UAVpWpaDBrB wQ8XlhGMULJpK2F1xqtxPX03y3F0I9OrkrEGikIM= Date: Sun, 11 Dec 2022 18:55:39 +0200 From: Laurent Pinchart To: Tomi Valkeinen Cc: 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 , Luca Ceresoli , Andy Shevchenko , Matti Vaittinen , 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 v5 1/8] i2c: core: let adapters be notified of client attach/detach Message-ID: References: <20221208104006.316606-1-tomi.valkeinen@ideasonboard.com> <20221208104006.316606-2-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221208104006.316606-2-tomi.valkeinen@ideasonboard.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Tomi and Luca, Thank you for the patch. On Thu, Dec 08, 2022 at 12:39:59PM +0200, Tomi Valkeinen wrote: > From: Luca Ceresoli > > An adapter might need to know when a new device is about to be > added. This will soon bee needed to implement an "I2C address > translator" (ATR for short), a device that propagates I2C transactions > with a different slave address (an "alias" address). An ATR driver > needs to know when a slave is being added to find a suitable alias and > program the device translation map. > > Add an attach/detach callback pair to allow adapter drivers to be > notified of clients being added and removed. This may be a stupid question, but couldn't you instead use the BUS_NOTIFY_ADD_DEVICE and BUS_NOTIFY_DEL_DEVICE bus notifiers ? > Signed-off-by: Luca Ceresoli > Signed-off-by: Tomi Valkeinen > --- > drivers/i2c/i2c-core-base.c | 18 +++++++++++++++++- > include/linux/i2c.h | 16 ++++++++++++++++ > 2 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index b4edf10e8fd0..c8bc71b1db82 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -966,15 +966,23 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf > } > } > > + if (adap->attach_ops && > + adap->attach_ops->attach_client && > + adap->attach_ops->attach_client(adap, info, client) != 0) > + goto out_remove_swnode; > + > status = device_register(&client->dev); > if (status) > - goto out_remove_swnode; > + goto out_detach_client; > > dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", > client->name, dev_name(&client->dev)); > > return client; > > +out_detach_client: > + if (adap->attach_ops && adap->attach_ops->detach_client) > + adap->attach_ops->detach_client(adap, client); > out_remove_swnode: > device_remove_software_node(&client->dev); > out_err_put_of_node: > @@ -996,9 +1004,17 @@ EXPORT_SYMBOL_GPL(i2c_new_client_device); > */ > void i2c_unregister_device(struct i2c_client *client) > { > + struct i2c_adapter *adap; > + > if (IS_ERR_OR_NULL(client)) > return; > > + adap = client->adapter; > + > + if (adap->attach_ops && > + adap->attach_ops->detach_client) > + adap->attach_ops->detach_client(adap, client); > + > if (client->dev.of_node) { > of_node_clear_flag(client->dev.of_node, OF_POPULATED); > of_node_put(client->dev.of_node); > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index f7c49bbdb8a1..9a385b6de388 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -584,6 +584,21 @@ struct i2c_lock_operations { > void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags); > }; > > +/** > + * struct i2c_attach_operations - callbacks to notify client attach/detach > + * @attach_client: Notify of new client being attached > + * @detach_client: Notify of new client being detached > + * > + * Both ops are optional. > + */ > +struct i2c_attach_operations { > + int (*attach_client)(struct i2c_adapter *adapter, > + const struct i2c_board_info *info, > + const struct i2c_client *client); > + void (*detach_client)(struct i2c_adapter *adapter, > + const struct i2c_client *client); > +}; > + > /** > * struct i2c_timings - I2C timing information > * @bus_freq_hz: the bus frequency in Hz > @@ -726,6 +741,7 @@ struct i2c_adapter { > > /* data fields that are valid for all devices */ > const struct i2c_lock_operations *lock_ops; > + const struct i2c_attach_operations *attach_ops; > struct rt_mutex bus_lock; > struct rt_mutex mux_lock; > -- Regards, Laurent Pinchart