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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA94AC433EF for ; Mon, 7 Mar 2022 14:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243298AbiCGOh1 (ORCPT ); Mon, 7 Mar 2022 09:37:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243285AbiCGOhZ (ORCPT ); Mon, 7 Mar 2022 09:37:25 -0500 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05B7F7E590; Mon, 7 Mar 2022 06:36:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646663790; x=1678199790; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=RhzWHO29ZNU2Nsn9nHyfYfEHvrdiuDbT4BJYyRMuu0I=; b=Aayj+mL0YZ+JlNuMti7p6qo1lj2/g9CDkPg4kqbuRAEcglkNv6TFKeT9 0+bfa2RmMM7Z5KwiBtjmoZzLvCtD6/GuKgXSlvIOVso0sdaR9NEq/LeRt 7p56BpZnAp+PAmN3cjrt66PGtfufIA9AE7Y+gLx6ACgnUdyYF3sJZk+mK CptZBx8yUMTErTDVvGGLQ4tQn15w6BcOEu78XQ2GPV8RFJKWs/DZm2aP6 Nl+AsdtveUb/cN5Y/d0B5HoXPfb2zKy3mDUXTHZfAoe8IhzvH7dhxQsXl xCo3KG2k3kKa3v9oZ/Z7D7oRgpRtUjpM0S00t8HvN16r370GmP3PeOnWe w==; X-IronPort-AV: E=McAfee;i="6200,9189,10278"; a="235012360" X-IronPort-AV: E=Sophos;i="5.90,162,1643702400"; d="scan'208";a="235012360" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2022 06:36:30 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,162,1643702400"; d="scan'208";a="687555371" Received: from kuha.fi.intel.com ([10.237.72.185]) by fmsmga001.fm.intel.com with SMTP; 07 Mar 2022 06:36:27 -0800 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Mon, 07 Mar 2022 16:36:27 +0200 Date: Mon, 7 Mar 2022 16:36:27 +0200 From: Heikki Krogerus To: Alvin =?utf-8?Q?=C5=A0ipraga?= Cc: Greg Kroah-Hartman , Rob Herring , =?utf-8?B?77+9aXByYWdh?= , linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] usb: typec: add TUSB320xA driver Message-ID: References: <20220301132010.115258-1-alvin@pqrs.dk> <20220301132010.115258-4-alvin@pqrs.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220301132010.115258-4-alvin@pqrs.dk> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Tue, Mar 01, 2022 at 02:20:07PM +0100, Alvin Šipraga wrote: > From: Alvin Šipraga > > The TUSB320LA and TUSB320HA (or LAI, HAI) chips are I2C controlled > non-PD Type-C port controllers. They support detection of cable > orientation, port attachment state, and role, including Audio Accessory > and Debug Accessory modes. Add a typec class driver for this family. > > Note that there already exists an extcon driver for the TUSB320 (a > slightly older revision that does not support setting role preference or > disabling the CC state machine). This driver is loosely based on that > one. This looked mostly OK to me. There is one question below. > +static int tusb320xa_check_signature(struct tusb320xa *tusb) > +{ > + static const char sig[] = { '\0', 'T', 'U', 'S', 'B', '3', '2', '0' }; > + unsigned int val; > + int i, ret; > + > + mutex_lock(&tusb->lock); > + > + for (i = 0; i < sizeof(sig); i++) { > + ret = regmap_read(tusb->regmap, sizeof(sig) - 1 - i, &val); > + if (ret) > + goto done; > + > + if (val != sig[i]) { > + dev_err(tusb->dev, "signature mismatch!\n"); > + ret = -ENODEV; > + goto done; > + } > + } > + > +done: > + mutex_unlock(&tusb->lock); > + > + return ret; > +} Couldn't that be done with a single read? char sig[8]; u64 val; strcpy(sig, "TUSB320") mutex_lock(&tusb->lock); ret = regmap_raw_read(tusb->regmap, 0, &val, sizeof(val)); ... if (val != cpu_to_le64(*(u64 *)sig)) { ... Something like that? thanks, -- heikki