From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [alsa-devel] [RFC PATCH 2/7] soundwire: add Slave sysfs support Date: Tue, 7 May 2019 10:49:59 +0530 Message-ID: <20190507051959.GC16052@vkoul-mobl> References: <20190504010030.29233-1-pierre-louis.bossart@linux.intel.com> <20190504010030.29233-3-pierre-louis.bossart@linux.intel.com> <20190504065444.GC9770@kroah.com> <20190506151953.GA13178@kroah.com> <20190506162208.GI3845@vkoul-mobl.Dlink> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Pierre-Louis Bossart Cc: Greg KH , alsa-devel@alsa-project.org, tiwai@suse.de, linux-kernel@vger.kernel.org, liam.r.girdwood@linux.intel.com, broonie@kernel.org, srinivas.kandagatla@linaro.org, jank@cadence.com, joe@perches.com, Sanyog Kale List-Id: alsa-devel@alsa-project.org On 06-05-19, 11:46, Pierre-Louis Bossart wrote: > On 5/6/19 11:22 AM, Vinod Koul wrote: > > On 06-05-19, 17:19, Greg KH wrote: > > > On Mon, May 06, 2019 at 09:42:35AM -0500, Pierre-Louis Bossart wrote: > > > > > > + > > > > > > +int sdw_sysfs_slave_init(struct sdw_slave *slave) > > > > > > +{ > > > > > > + struct sdw_slave_sysfs *sysfs; > > > > > > + unsigned int src_dpns, sink_dpns, i, j; > > > > > > + int err; > > > > > > + > > > > > > + if (slave->sysfs) { > > > > > > + dev_err(&slave->dev, "SDW Slave sysfs is already initialized\n"); > > > > > > + err = -EIO; > > > > > > + goto err_ret; > > > > > > + } > > > > > > + > > > > > > + sysfs = kzalloc(sizeof(*sysfs), GFP_KERNEL); > > > > > > > > > > Same question as patch 1, why a new device? > > > > > > > > yes it's the same open. In this case, the slave devices are defined at a > > > > different level so it's also confusing to create a device to represent the > > > > slave properties. The code works but I am not sure the initial directions > > > > are correct. > > > > > > You can just make a subdir for your attributes by using the attribute > > > group name, if a subdirectory is needed just to keep things a bit more > > > organized. > > > > The key here is 'a subdir' which is not the case here. We did discuss > > this in the initial patches for SoundWire which had sysfs :) > > > > The way MIPI disco spec organized properties, we have dp0 and dpN > > properties each of them requires to have a subdir of their own and that > > was the reason why I coded it to be creating a device. > > Vinod, the question was not for dp0 and dpN, it's fine to have > subdirectories there, but rather why we need separate devices for the master > and slave properties. Slave does not have a separate device. IIRC the properties for Slave are in /sys/bus/soundwire/device//... For master yes we can skip the device creation, it was done for consistency sake of having these properties ties into sys/bus/soundwire/ I don't mind if they are shown up in respective device node (PCI/platform etc) /sys/bus/foo/device/<> But for creating subdirectories you would need the new dpX devices. HTH > > > > > Do we have a better way to handle this? > > > > > Otherwise, you need to mess with having multiple "types" of struct > > > device all associated with the same bus. It is possible, and not that > > > hard, but I don't think you are doing that here. > > > > > > thnaks, > > > > > > greg k-h > > -- ~Vinod