From patchwork Wed Jun 16 15:57:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 12325577 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=-13.8 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 autolearn=ham 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 E281CC48BE6 for ; Wed, 16 Jun 2021 15:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C35C661159 for ; Wed, 16 Jun 2021 15:58:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234520AbhFPQA3 (ORCPT ); Wed, 16 Jun 2021 12:00:29 -0400 Received: from aposti.net ([89.234.176.197]:51058 "EHLO aposti.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235148AbhFPQAP (ORCPT ); Wed, 16 Jun 2021 12:00:15 -0400 From: Paul Cercueil To: Jonathan Cameron , Lars-Peter Clausen Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Cercueil Subject: [PATCH v2 2/2] iio: core: Support reading extended name as label Date: Wed, 16 Jun 2021 16:57:06 +0100 Message-Id: <20210616155706.17444-3-paul@crapouillou.net> In-Reply-To: <20210616155706.17444-1-paul@crapouillou.net> References: <20210616155706.17444-1-paul@crapouillou.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The point of this new change is to make the IIO tree actually parsable. Before, given this attribute as a filename: in_voltage0_aux_sample_rate Userspace had no way to know if the attribute name was "aux_sample_rate" with no extended name, or "sample_rate" with "aux" as the extended name, or just "rate" with "aux_sample" as the extended name. This was somewhat possible to deduce when there was more than one attribute present for a given channel, e.g: in_voltage0_aux_sample_rate in_voltage0_aux_frequency There, it was possible to deduce that "aux" was the extended name. But even with more than one attribute, this wasn't very robust, as two attributes starting with the same prefix (e.g. "sample_rate" and "sample_size") would result in the first part of the prefix being interpreted as being part of the extended name. To address the issue, knowing that channels will never have both a label and an extended name, set the channel's label to the extended name. In this case, the label's attribute will also have the extended name in its filename, but we can live with that - userspace can open in_voltage0__label and verify that it returns to obtain the extended name. Signed-off-by: Paul Cercueil --- drivers/iio/industrialio-core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 81f40dab778a..9b37e96538c2 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -717,8 +717,12 @@ static ssize_t iio_read_channel_label(struct device *dev, struct iio_dev *indio_dev = dev_to_iio_dev(dev); struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); - if (!indio_dev->info->read_label) - return -EINVAL; + if (!indio_dev->info->read_label) { + if (this_attr->c->extend_name) + return sprintf(buf, "%s\n", this_attr->c->extend_name); + else + return -EINVAL; + } return indio_dev->info->read_label(indio_dev, this_attr->c, buf); } @@ -1160,7 +1164,7 @@ static int iio_device_add_channel_label(struct iio_dev *indio_dev, struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); int ret; - if (!indio_dev->info->read_label) + if (!indio_dev->info->read_label && !chan->extend_name) return 0; ret = __iio_add_chan_devattr("label",