From patchwork Wed May 18 20:41:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eddie James X-Patchwork-Id: 12854083 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 1AA7BC433FE for ; Wed, 18 May 2022 20:41:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242710AbiERUlo (ORCPT ); Wed, 18 May 2022 16:41:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242701AbiERUln (ORCPT ); Wed, 18 May 2022 16:41:43 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 763016D973; Wed, 18 May 2022 13:41:42 -0700 (PDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24IKW81u021315; Wed, 18 May 2022 20:41:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=6Wb1PTNRCtiyiy1UokxHKChzuywEapNSam8gp2jnpt0=; b=Vl3k4om3rUSgWcvytmRPd8gy42NxeB3ArLfct+5Ln++rYLxB/BznjNTyq48ElfJowrEh XbsZGJiBQJADTjsjwDfvQpkPuQrXgTs/INlr2UV5+7/+Al6HV2DMYPkO8TpamxAUBJ91 GjXnL0Z91ckJv1jWWaHJovhGYVfI3rBGihb7hwUvs3hrsCNjp7iW4fCU3Z+fj8LVJ7B6 mqu0oy+RBKwwVseA0gE6DRbXQIusIHV7IDUTsGZfKmxwmu4Zzr6ocFidLtz5O3fuQeCB BpWcmZpBd6LqGiC/jayO2fbHLKemfe4Yak2MjH97pkoFz/KkHpV2Ew8ffmRC4WKL9Uq3 nQ== Received: from ppma01dal.us.ibm.com (83.d6.3fa9.ip4.static.sl-reverse.com [169.63.214.131]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g57x0r7yw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 18 May 2022 20:41:26 +0000 Received: from pps.filterd (ppma01dal.us.ibm.com [127.0.0.1]) by ppma01dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 24IKcb8N003416; Wed, 18 May 2022 20:41:25 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma01dal.us.ibm.com with ESMTP id 3g242beprn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 18 May 2022 20:41:25 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 24IKfOnX8782234 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 May 2022 20:41:24 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 60794C6055; Wed, 18 May 2022 20:41:24 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F153EC6059; Wed, 18 May 2022 20:41:23 +0000 (GMT) Received: from v0005c16.aus.stglabs.ibm.com (unknown [9.163.6.139]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Wed, 18 May 2022 20:41:23 +0000 (GMT) From: Eddie James To: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, jic23@kernel.org, lars@metafoo.de, wsa@kernel.org, milton@us.ibm.com, peda@axentia.se, Eddie James Subject: [RFC 1/2] i2c: core: Add adapter transfer callback Date: Wed, 18 May 2022 15:41:18 -0500 Message-Id: <20220518204119.38943-2-eajames@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220518204119.38943-1-eajames@linux.ibm.com> References: <20220518204119.38943-1-eajames@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: S_9GnWowkBKxopX2J-FT3fRZw8U_kvar X-Proofpoint-ORIG-GUID: S_9GnWowkBKxopX2J-FT3fRZw8U_kvar X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-18_06,2022-05-17_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 impostorscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=894 malwarescore=0 clxscore=1015 adultscore=0 priorityscore=1501 suspectscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205180119 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Add a callback function pointer to be executed after the adapter performs a transfer. The purpose of such a callback is for a client to execute some code while "owning" the bus entirely. Holding the adapter lock is insufficient in the case where the client is behind a mux, as the mux driver could perform mux selection operations on the bus while locked. Signed-off-by: Eddie James --- drivers/i2c/i2c-core-base.c | 3 +++ include/linux/i2c.h | 25 +++++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index d43db2c3876e..a46bfee2d845 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -2128,6 +2128,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) trace_i2c_result(adap, num, ret); } + if (adap->xfer_callback) + adap->xfer_callback(adap->xfer_data, ret); + return ret; } EXPORT_SYMBOL(__i2c_transfer); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index fbda5ada2afc..ea773f2ee9c8 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -747,6 +747,9 @@ struct i2c_adapter { struct irq_domain *host_notify_domain; struct regulator *bus_regulator; + + void (*xfer_callback)(void *data, int xfer_rc); + void *xfer_data; }; #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) @@ -814,6 +817,7 @@ i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags) static inline void i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags) { + adapter->xfer_callback = NULL; adapter->lock_ops->unlock_bus(adapter, flags); } @@ -849,6 +853,27 @@ static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap) i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER); } +/** + * i2c_adapter_xfer_callback - Register a callback function that is executed + * when a transfer completes. + * @adap: Adapter to which the callback function will be registered + * @cb: The callback function pointer + * @data: The data to pass to the callback function + * + * This function should be called with the adapter locked with + * I2C_LOCK_ROOT_ADAPTER to ensure that the whole bus is idle while the + * callback executes. + * The callback is automatically removed when the bus is unlocked to avoid + * spurious executions of the callback. + */ +static inline void i2c_adapter_xfer_callback(struct i2c_adapter *adap, + void (*cb)(void *data, int rc), + void *data) +{ + adap->xfer_callback = cb; + adap->xfer_data = data; +} + /* i2c adapter classes (bitmask) */ #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */