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Thu, 17 Sep 2020 11:19:56 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id DAE35F80212; Thu, 17 Sep 2020 11:19:53 +0200 (CEST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 61B86F80134 for ; Thu, 17 Sep 2020 11:19:46 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 61B86F80134 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="iD+/NVQq" Received: from localhost (unknown [84.241.193.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 86B6F2076D; Thu, 17 Sep 2020 09:19:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600334383; bh=61LQFl0Bi+36GrTV+XHIdLj5K2TODmWdVdqWZZmc7Cs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iD+/NVQqzZhTDOrrw42PprRGghRSQs3AwCxNMwuHFIrw1qWGztTpNVRVhVG85nD0d W4r2IQkUcx+gSWq2G/6gvhVa9JSNaT7H+ODUf2n+AnQ09yxVoGN/L2dVUGvi71Xsqg XdZHXc/vCSTKDzTN1VBR3uML2joC3M994QXTFmMk= Date: Thu, 17 Sep 2020 11:19:38 +0200 From: Greg KH To: Pierre-Louis Bossart Subject: Re: [PATCH 2/2] soundwire: sysfs: add slave status and device number before probe Message-ID: <20200917091938.GB52206@kroah.com> References: <20200916201504.52211-1-pierre-louis.bossart@linux.intel.com> <20200916201504.52211-3-pierre-louis.bossart@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200916201504.52211-3-pierre-louis.bossart@linux.intel.com> Cc: Guennadi Liakhovetski , alsa-devel@alsa-project.org, tiwai@suse.de, vkoul@kernel.org, broonie@kernel.org, srinivas.kandagatla@linaro.org, Bard liao , Rander Wang X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Wed, Sep 16, 2020 at 03:15:04PM -0500, Pierre-Louis Bossart wrote: > The MIPI DisCo device properties that are read by the driver from > platform firmware, or hard-coded in the driver, should only be > provided as sysfs entries when a driver probes successfully. > > However the device status and device number is updated even when there > is no driver present, and hence can be updated when a Slave device is > detected on the bus without being described in platform firmware and > without any driver registered/probed. > > The attr group added for Slave status and device number is not handled > by devm_ routines to avoid errors such as "Resources present before > probing". Since device_del() explicitly removes attribute groups, only > an init function is provided. > > Credits to Vinod Koul for the status_show() function, shared in a > separate patch and used as is here. The status table was modified to > remove an unnecessary enum and status_show() is handled in a different > group attribute than what was suggested by Vinod. > > Reviewed-by: Bard Liao > Reviewed-by: Rander Wang > Reviewed-by: Guennadi Liakhovetski > Tested-by: Srinivas Kandgatla > Signed-off-by: Pierre-Louis Bossart > --- > .../ABI/testing/sysfs-bus-soundwire-slave | 18 ++++++ > drivers/soundwire/slave.c | 2 + > drivers/soundwire/sysfs_local.h | 4 ++ > drivers/soundwire/sysfs_slave.c | 64 ++++++++++++++++++- > 4 files changed, 87 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-soundwire-slave b/Documentation/ABI/testing/sysfs-bus-soundwire-slave > index db4c9511d1aa..425adf7b8aec 100644 > --- a/Documentation/ABI/testing/sysfs-bus-soundwire-slave > +++ b/Documentation/ABI/testing/sysfs-bus-soundwire-slave > @@ -1,3 +1,21 @@ > +What: /sys/bus/soundwire/devices/sdw:.../dev-status/status > + /sys/bus/soundwire/devices/sdw:.../dev-status/device_number > + > +Date: September 2020 > + > +Contact: Pierre-Louis Bossart > + Bard Liao > + Vinod Koul > + > +Description: SoundWire Slave status > + > + These properties report the Slave status, e.g. if it > + is UNATTACHED or not, and in the latter case show the > + device_number. This status information is useful to > + detect devices exposed by platform firmware but not > + physically present on the bus, and conversely devices > + not exposed in platform firmware but enumerated. > + > What: /sys/bus/soundwire/devices/sdw:.../dev-properties/mipi_revision > /sys/bus/soundwire/devices/sdw:.../dev-properties/wake_capable > /sys/bus/soundwire/devices/sdw:.../dev-properties/test_mode_capable > diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c > index 19b012310c29..ee554a215e44 100644 > --- a/drivers/soundwire/slave.c > +++ b/drivers/soundwire/slave.c > @@ -6,6 +6,7 @@ > #include > #include > #include "bus.h" > +#include "sysfs_local.h" > > static void sdw_slave_release(struct device *dev) > { > @@ -83,6 +84,7 @@ int sdw_slave_add(struct sdw_bus *bus, > return ret; > } > sdw_slave_debugfs_init(slave); > + sdw_slave_status_sysfs_init(slave); > > return ret; > } > diff --git a/drivers/soundwire/sysfs_local.h b/drivers/soundwire/sysfs_local.h > index ff60adee3c41..52f2eabf5b4b 100644 > --- a/drivers/soundwire/sysfs_local.h > +++ b/drivers/soundwire/sysfs_local.h > @@ -8,6 +8,10 @@ > * SDW sysfs APIs - > */ > > +/* basic routine to report status of Slave (attachment, dev_num) */ > +int sdw_slave_status_sysfs_init(struct sdw_slave *slave); > + > +/* additional device-managed properties reported after driver probe */ > int sdw_slave_sysfs_init(struct sdw_slave *slave); > int sdw_slave_sysfs_dpn_init(struct sdw_slave *slave); > > diff --git a/drivers/soundwire/sysfs_slave.c b/drivers/soundwire/sysfs_slave.c > index f510071b0add..36eaca343601 100644 > --- a/drivers/soundwire/sysfs_slave.c > +++ b/drivers/soundwire/sysfs_slave.c > @@ -16,10 +16,14 @@ > > /* > * The sysfs for Slave reflects the MIPI description as given > - * in the MIPI DisCo spec > + * in the MIPI DisCo spec. dev-status properties come directly > + * from the MIPI SoundWire specification. > * > * Base file is device > * |---- modalias > + * |---- dev-status > + * |---- status > + * |---- device_number > * |---- dev-properties > * |---- mipi_revision > * |---- wake_capable > @@ -212,3 +216,61 @@ int sdw_slave_sysfs_init(struct sdw_slave *slave) > > return 0; > } > + > +/* > + * the status is shown in capital letters for UNATTACHED and RESERVED > + * on purpose, to alert users to the fact that these status values are > + * not expected. > + */ > +static const char *const slave_status[] = { > + [SDW_SLAVE_UNATTACHED] = "UNATTACHED", > + [SDW_SLAVE_ATTACHED] = "Attached", > + [SDW_SLAVE_ALERT] = "Alert", > + [SDW_SLAVE_RESERVED] = "RESERVED", > +}; > + > +static ssize_t status_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct sdw_slave *slave = dev_to_sdw_dev(dev); > + > + return sprintf(buf, "%s\n", slave_status[slave->status]); > +} > +static DEVICE_ATTR_RO(status); > + > +static ssize_t device_number_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct sdw_slave *slave = dev_to_sdw_dev(dev); > + > + if (slave->status == SDW_SLAVE_UNATTACHED) > + return sprintf(buf, "%s", "N/A"); > + else > + return sprintf(buf, "%d", slave->dev_num); > +} > +static DEVICE_ATTR_RO(device_number); > + > +static struct attribute *slave_status_attrs[] = { > + &dev_attr_status.attr, > + &dev_attr_device_number.attr, > + NULL, > +}; > + > +/* > + * we don't use ATTRIBUTES_GROUP here since we want to add a subdirectory > + * for device-status > + */ > +static struct attribute_group sdw_slave_status_attr_group = { > + .attrs = slave_status_attrs, > + .name = "dev-status", > +}; > + > +/* > + * We can't use devm_ here, otherwise resources would be added before > + * the driver probe. The group is removed in device_del() however. > + */ > + > +int sdw_slave_status_sysfs_init(struct sdw_slave *slave) > +{ > + return device_add_group(&slave->dev, &sdw_slave_status_attr_group); DOesn't this race with userspace? Why not make this part of the default set of device attributes and have the driver core create them automatically? thanks, greg k-h