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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 EF063C4321A for ; Fri, 22 Jan 2021 17:31:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA5DD239D4 for ; Fri, 22 Jan 2021 17:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730027AbhAVRam (ORCPT ); Fri, 22 Jan 2021 12:30:42 -0500 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:11902 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729093AbhAVP4T (ORCPT ); Fri, 22 Jan 2021 10:56:19 -0500 Received: from pps.filterd (m0167088.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 10MFU0BV004515; Fri, 22 Jan 2021 10:55:22 -0500 Received: from nwd2mta4.analog.com ([137.71.173.58]) by mx0a-00128a01.pphosted.com with ESMTP id 3668rcjhwk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 22 Jan 2021 10:55:22 -0500 Received: from SCSQMBX10.ad.analog.com (SCSQMBX10.ad.analog.com [10.77.17.5]) by nwd2mta4.analog.com (8.14.7/8.14.7) with ESMTP id 10MFtKVl002547 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 22 Jan 2021 10:55:21 -0500 Received: from SCSQCASHYB7.ad.analog.com (10.77.17.133) by SCSQMBX10.ad.analog.com (10.77.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.721.2; Fri, 22 Jan 2021 07:55:19 -0800 Received: from SCSQMBX11.ad.analog.com (10.77.17.10) by SCSQCASHYB7.ad.analog.com (10.77.17.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.721.2; Fri, 22 Jan 2021 07:55:19 -0800 Received: from zeus.spd.analog.com (10.66.68.11) by SCSQMBX11.ad.analog.com (10.77.17.10) with Microsoft SMTP Server id 15.1.1779.2 via Frontend Transport; Fri, 22 Jan 2021 07:55:18 -0800 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 10MFtF54014933; Fri, 22 Jan 2021 10:55:17 -0500 From: Alexandru Ardelean To: , CC: , , , , , Alexandru Ardelean Subject: [PATCH v2 01/12] iio: core: register chardev only if needed Date: Fri, 22 Jan 2021 17:57:54 +0200 Message-ID: <20210122155805.83012-2-alexandru.ardelean@analog.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210122155805.83012-1-alexandru.ardelean@analog.com> References: <20210122155805.83012-1-alexandru.ardelean@analog.com> MIME-Version: 1.0 Content-Type: text/plain X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343,18.0.737 definitions=2021-01-22_11:2021-01-22,2021-01-22 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 mlxscore=0 spamscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 clxscore=1015 suspectscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101220087 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We only need a chardev if we need to support buffers and/or events. With this change, a chardev will be created only if an IIO buffer is attached OR an event_interface is configured. Otherwise, no chardev will be created, and the IIO device will get registered with the 'device_add()' call. Quite a lot of IIO devices don't really need a chardev, so this is a minor improvement to the IIO core, as the IIO device will take up (slightly) fewer resources. In order to not create a chardev, we mostly just need to not initialize the indio_dev->dev.devt field. If that is un-initialized, cdev_device_add() behaves like device_add(). Signed-off-by: Alexandru Ardelean --- drivers/iio/industrialio-core.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 7db761afa578..0a6fd299a978 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -1761,6 +1761,15 @@ static const struct file_operations iio_buffer_fileops = { .release = iio_chrdev_release, }; +static const struct file_operations iio_event_fileops = { + .owner = THIS_MODULE, + .llseek = noop_llseek, + .unlocked_ioctl = iio_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = iio_chrdev_open, + .release = iio_chrdev_release, +}; + static int iio_check_unique_scan_index(struct iio_dev *indio_dev) { int i, j; @@ -1788,6 +1797,7 @@ static const struct iio_buffer_setup_ops noop_ring_setup_ops; int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod) { + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); int ret; if (!indio_dev->info) @@ -1805,9 +1815,6 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod) if (ret < 0) return ret; - /* configure elements for the chrdev */ - indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id); - iio_device_register_debugfs(indio_dev); ret = iio_buffer_alloc_sysfs_and_mask(indio_dev); @@ -1836,9 +1843,15 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod) indio_dev->setup_ops == NULL) indio_dev->setup_ops = &noop_ring_setup_ops; - cdev_init(&indio_dev->chrdev, &iio_buffer_fileops); + if (indio_dev->buffer) + cdev_init(&indio_dev->chrdev, &iio_buffer_fileops); + else if (iio_dev_opaque->event_interface) + cdev_init(&indio_dev->chrdev, &iio_event_fileops); - indio_dev->chrdev.owner = this_mod; + if (indio_dev->buffer || iio_dev_opaque->event_interface) { + indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id); + indio_dev->chrdev.owner = this_mod; + } ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev); if (ret < 0) -- 2.17.1