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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 71E78C4338F for ; Mon, 23 Aug 2021 09:29:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A63C613A2 for ; Mon, 23 Aug 2021 09:29:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232124AbhHWJaZ (ORCPT ); Mon, 23 Aug 2021 05:30:25 -0400 Received: from mail.thorsis.com ([92.198.35.195]:49180 "EHLO mail.thorsis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231160AbhHWJaY (ORCPT ); Mon, 23 Aug 2021 05:30:24 -0400 X-Greylist: delayed 303 seconds by postgrey-1.27 at vger.kernel.org; Mon, 23 Aug 2021 05:30:24 EDT Received: from localhost (localhost [127.0.0.1]) by mail.thorsis.com (Postfix) with ESMTP id EFC3C2985; Mon, 23 Aug 2021 11:24:38 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mail.thorsis.com Received: from mail.thorsis.com ([127.0.0.1]) by localhost (mail.thorsis.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OJWpy4L88Gne; Mon, 23 Aug 2021 11:24:38 +0200 (CEST) Received: by mail.thorsis.com (Postfix, from userid 109) id CE46B29CF; Mon, 23 Aug 2021 11:24:38 +0200 (CEST) From: Alexander Dahl To: linux-usb@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, rca@thorsis.com Subject: Enable HSIC Host Port on Atmel/Microchip SAMA5D2 Date: Mon, 23 Aug 2021 11:24:35 +0200 Message-ID: <2869763.XZdSvA6Ref@ada> Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hello, for a new embedded board featuring a Microchip SAMA5D2 SoC (64 MiB SiP variant SAMA5D27C-D5M) we connected the third USB host port (HSIC only) with an USB3503 hub chip. This doesn't work out of the box with the Linux kernel currently, because neither the SoC nor the kernel does enable the HSIC interface by default. That SoC has three USB host ports, from the SAMA5D2 Series Datasheet [1] I learned there's a flag in an EHCI register, which has to be set to enable the HSIC interface on port C, the third port. (Section "41.7.14 EHCI: REG08 - HSIC Enable/Disable" of the datasheet.) I suppose that register is vendor specific. The register definitions in '/include/linux/usb/ehci_def.h' do not contain that register. Where would I add that register definition and set that flag in the kernel then? I suppose in the vendor specific ehci driver? That would be 'drivers/usb/host/ehci-atmel.c' right? Since that feature is optional (other boards don't need to turn on hsic on that port), some driver specific new device tree binding would be necessary, right? I suppose that would have to be documented in 'Documentation/ devicetree/bindings/usb/atmel-usb.txt' right? (Or that would have to be converted to yaml first?) Is this the right track? If yes, I'm going to develop patches for this. Otherwise any hint into the right direction are highly appreciated. FWIW, I'm not the first one struggling [2] with this problem. ;-) Greets Alex [1] https://www.microchip.com/en-us/product/ATSAMA5D27C-D5M#document-table [2] https://community.atmel.com/forum/sama5d2-using-hsic-under-linux