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=-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 4CF97C47082 for ; Tue, 8 Jun 2021 23:33:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F6C761246 for ; Tue, 8 Jun 2021 23:33:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234992AbhFHXf2 (ORCPT ); Tue, 8 Jun 2021 19:35:28 -0400 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:56497 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234770AbhFHXf1 (ORCPT ); Tue, 8 Jun 2021 19:35:27 -0400 Received: (Authenticated sender: alexandre.belloni@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 77F6E20002; Tue, 8 Jun 2021 23:33:27 +0000 (UTC) Date: Wed, 9 Jun 2021 01:33:26 +0200 From: Alexandre Belloni To: Parshuram Thombare Cc: slongerbeam@gmail.com, vitor.soares@synopsys.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org, mparab@cadence.com, praneeth@ti.com Subject: Re: [PATCH v10 6/7] i3c: master: sysfs key for acquire bus Message-ID: References: <1606716983-3645-1-git-send-email-pthombar@cadence.com> <1606717202-4206-1-git-send-email-pthombar@cadence.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1606717202-4206-1-git-send-email-pthombar@cadence.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/11/2020 07:20:02+0100, Parshuram Thombare wrote: > Added support to acquire I3C bus through sysfs interface. > > Signed-off-by: Parshuram Thombare > --- > drivers/i3c/master.c | 18 ++++++++++++++++++ > 1 files changed, 18 insertions(+), 0 deletions(-) > > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c > index c01ba00..beb7495 100644 > --- a/drivers/i3c/master.c > +++ b/drivers/i3c/master.c > @@ -581,6 +581,23 @@ static ssize_t i2c_scl_frequency_show(struct device *dev, > } > static DEVICE_ATTR_RO(i2c_scl_frequency); > > +static ssize_t i3c_acquire_bus_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct i3c_master_controller *master = dev_to_i3cmaster(dev); > + int ret; > + > + i3c_bus_normaluse_lock(&master->bus); > + ret = i3c_master_acquire_bus(master); > + i3c_bus_normaluse_unlock(&master->bus); > + if (!ret) > + i3c_master_enable_mr_events(master); > + > + return ret ?: count; > +} > +static DEVICE_ATTR_WO(i3c_acquire_bus); > + I'm wondering whether we should allow userspace to actually control that. Shouldn't we simply request mastership when a driver needs to talk to a device on the bus? Is it really useful to have that until there is an i3c-dev userspace interface? > static struct attribute *i3c_masterdev_attrs[] = { > &dev_attr_mode.attr, > &dev_attr_current_master.attr, > @@ -591,6 +608,7 @@ static ssize_t i2c_scl_frequency_show(struct device *dev, > &dev_attr_pid.attr, > &dev_attr_dynamic_address.attr, > &dev_attr_hdrcap.attr, > + &dev_attr_i3c_acquire_bus.attr, > NULL, > }; > ATTRIBUTE_GROUPS(i3c_masterdev); > -- > 1.7.1 > -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com