From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [alsa-devel] [RFC PATCH 2/7] soundwire: add Slave sysfs support Date: Mon, 6 May 2019 11:46:06 -0500 Message-ID: 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=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190506162208.GI3845@vkoul-mobl.Dlink> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Vinod Koul , Greg KH Cc: 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 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. > > 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 >