From patchwork Sun Feb 6 11:59:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 12736558 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 446B0C4332F for ; Sun, 6 Feb 2022 13:58:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242190AbiBFN6y (ORCPT ); Sun, 6 Feb 2022 08:58:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242164AbiBFN6s (ORCPT ); Sun, 6 Feb 2022 08:58:48 -0500 Received: from hostingweb31-40.netsons.net (hostingweb31-40.netsons.net [89.40.174.40]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A74EC0401E3; Sun, 6 Feb 2022 05:58:38 -0800 (PST) Received: from [77.244.183.192] (port=63680 helo=melee.fritz.box) by hostingweb31.netsons.net with esmtpa (Exim 4.94.2) (envelope-from ) id 1nGgD1-00059v-Kg; Sun, 06 Feb 2022 12:59:59 +0100 From: Luca Ceresoli To: linux-media@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , Mark Rutland , Wolfram Sang , Sakari Ailus , Hans Verkuil , Laurent Pinchart , Kieran Bingham , Jacopo Mondi , Vladimir Zapolskiy , Peter Rosin , Mauro Carvalho Chehab , Tomi Valkeinen , matti.vaittinen@fi.rohmeurope.com Subject: [RFCv3 1/6] i2c: core: let adapters be notified of client attach/detach Date: Sun, 6 Feb 2022 12:59:34 +0100 Message-Id: <20220206115939.3091265-2-luca@lucaceresoli.net> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220206115939.3091265-1-luca@lucaceresoli.net> References: <20220206115939.3091265-1-luca@lucaceresoli.net> MIME-Version: 1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - hostingweb31.netsons.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lucaceresoli.net X-Get-Message-Sender-Via: hostingweb31.netsons.net: authenticated_id: luca+lucaceresoli.net/only user confirmed/virtual account not confirmed X-Authenticated-Sender: hostingweb31.netsons.net: luca@lucaceresoli.net X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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. Signed-off-by: Luca Ceresoli --- Changes RFCv2 -> RFCv3: - rebase on current master Changes RFCv1 -> RFCv2: - Document struct i2c_attach_operations --- 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 2c59dd748a49..aea1e1b552b0 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 7d4f52ceb7b5..aadd71e0533c 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -587,6 +587,21 @@ 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 @@ -729,6 +744,7 @@ 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;