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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no 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 65183C433DB for ; Mon, 15 Feb 2021 18:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3808864DFF for ; Mon, 15 Feb 2021 18:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230117AbhBOSWU (ORCPT ); Mon, 15 Feb 2021 13:22:20 -0500 Received: from mail.nic.cz ([217.31.204.67]:45998 "EHLO mail.nic.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229996AbhBOSWI (ORCPT ); Mon, 15 Feb 2021 13:22:08 -0500 Received: from localhost (unknown [IPv6:2a0e:b107:ae1:0:3e97:eff:fe61:c680]) by mail.nic.cz (Postfix) with ESMTPSA id ECB11140A60; Mon, 15 Feb 2021 19:21:24 +0100 (CET) Date: Mon, 15 Feb 2021 19:21:24 +0100 From: Marek Behun To: Roderick Colenbrander Cc: Jiri Kosina , Benjamin Tissoires , Pavel Machek , Dmitry Torokhov , "open list:HID CORE LAYER" , linux-leds@vger.kernel.org, Roderick Colenbrander Subject: Re: [PATCH v6 1/4] HID: playstation: add DualSense lightbar support Message-ID: <20210215192124.7a6c8c9d@nic.cz> In-Reply-To: References: <20210215004549.135251-1-roderick@gaikai.com> <20210215004549.135251-2-roderick@gaikai.com> <20210215143144.060fdbe6@nic.cz> <20210215165518.16033bb6@nic.cz> X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.102.2 at mail X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org On Mon, 15 Feb 2021 09:51:15 -0800 Roderick Colenbrander wrote: > On Mon, Feb 15, 2021 at 7:55 AM Marek Behun wrote: > > > > On Mon, 15 Feb 2021 07:36:58 -0800 > > Roderick Colenbrander wrote: > > > > > Hi Marek, > > > > > > On Mon, Feb 15, 2021 at 5:31 AM Marek Behun wrote: > > > > > > > > On Sun, 14 Feb 2021 16:45:46 -0800 > > > > Roderick Colenbrander wrote: > > > > > > > > > + led_cdev->name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "playstation::%pMR::rgb", > > > > > + ps_dev->mac_address); > > > > ... > > > > > + ret = devm_led_classdev_multicolor_register(&hdev->dev, lightbar_mc_dev); > > > > > > > > The LED subsystem has a predefined schema by which LED names should > > > > look like: > > > > devicename:color:function > > > > (Not all fields are required, but the order must be preserved. The ':' > > > > character should be used only as separator of these fields, so not MAC > > > > addresses in these names, it will confuse userspace parsers.) > > > > See Documentation/leds/leds-class.rst > > > > > > > > The devicename part should not be "playstation". It should be something > > > > otherwise recognizable from userspace. For example an mmc indicator has > > > > devicename "mmc0", keyboard capslock LED can have devicename "input0"... > > > > > > > > In your case the name should be something like: > > > > input3:rgb:indicator > > > > > > Naming is a little bit tricky. The LEDs as well as other sysfs nodes > > > are added to the 'parent' HID device, not the input devices. In case > > > of DualSense it is actually implemented as a composite device with > > > mulitple input devices (gamepad, touchpad and motion sensors) per HID > > > device. The device name of HID devices seems to be something like: > > > ::: e.g. for DualSense USB > > > 0003:054C:0CE6.0029 or Bluetooth 0005:054C:0CE6.002B > > > > > > This is I guess why many HID devices in general pick their own names > > > (and not all have need to have input devices I guess). Though Benjamin > > > and Jiri know better. > > > > > > I'm not sure what naming could make sense here. The previous Sony > > > driver for PlayStation devices used: HID_name "::red" for e.g. red LED > > > on DualShock 4. > > > > We have to find a reasonable devicename here. If each joystick registers > > multiple input devices, it cannot be "input%d". I suppose there isn't > > an API for grouping mulitple input devices toghether into inputgroups. > > Maybe it could be in the format "joystick%d". > > Yeah, there is no inputgroups mechanism. It could use some type of > joystick name if that's what desired. However, there is no common ID > code. Individual drivers are sometimes calculating their own IDs > (hid-nintendo, hid-sony, hid-playstation and xpad I think). At least > for hid-sony/hid-playstation the use case for tracking IDs is for a > part to prevent duplicate devices as you can connect your device using > both bluetooth and USB. So would be "ps-joystick0" > > At the HID layer there does seem to be a unique ID, but it is only > exposed in the name string: This is how the name is constructed: > dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus, > hdev->vendor, hdev->product, atomic_inc_return(&id)); > > This ID is HID specific, but not all input devices use HID. > > I'm not entirely sure what makes sense... So all HIDs can be uniqely determined via this atomic_inc_return(&id), but it is only stored in string form as part of device name. Send a patch to hid-core to make this atomic_inc_return(&id) also be stored into struct hid_device as an integer, not only as a part of the device name string. Then use "hid%d" as the devicename for this LED, with %d substituted with this ID. Marek