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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 648FBC8300B for ; Thu, 30 Apr 2020 12:07:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4982E20757 for ; Thu, 30 Apr 2020 12:07:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726685AbgD3MHv (ORCPT ); Thu, 30 Apr 2020 08:07:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725280AbgD3MHv (ORCPT ); Thu, 30 Apr 2020 08:07:51 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54016C035494 for ; Thu, 30 Apr 2020 05:07:51 -0700 (PDT) Received: from dude02.hi.pengutronix.de ([2001:67c:670:100:1d::28] helo=dude02.lab.pengutronix.de) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jU7yj-0004Mv-40; Thu, 30 Apr 2020 14:07:45 +0200 Received: from mfe by dude02.lab.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1jU7yf-00079d-1G; Thu, 30 Apr 2020 14:07:41 +0200 Date: Thu, 30 Apr 2020 14:07:41 +0200 From: Marco Felsch To: Sakari Ailus Cc: Robert Foss , Andy Shevchenko , Maxime Ripard , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dongchun Zhu , Fabio Estevam , Tomasz Figa Subject: Re: [PATCH v6 2/3] media: ov8856: Add devicetree support Message-ID: <20200430120740.GG2188@pengutronix.de> References: <20200429162437.2025699-1-robert.foss@linaro.org> <20200429162437.2025699-3-robert.foss@linaro.org> <20200430093524.GB2188@pengutronix.de> <20200430094549.GF867@valkosipuli.retiisi.org.uk> <20200430095332.GC2188@pengutronix.de> <20200430095907.GG867@valkosipuli.retiisi.org.uk> <20200430101157.GD2188@pengutronix.de> <20200430102018.GI867@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200430102018.GI867@valkosipuli.retiisi.org.uk> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 13:58:29 up 68 days, 23:15, 99 users, load average: 0.11, 0.20, 0.29 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::28 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 20-04-30 13:20, Sakari Ailus wrote: > On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote: > > On 20-04-30 12:59, Sakari Ailus wrote: > > > Hi Marco, > > > > > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote: > > > > Hi Sakari, > > > > > > > > On 20-04-30 12:45, Sakari Ailus wrote: > > > > > Hi Marco, > > > > > > > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote: > > > > ... > > > > > > > > > - if (mclk != OV8856_MCLK) { > > > > > > > - dev_err(dev, "external clock %d is not supported", mclk); > > > > > > > - return -EINVAL; > > > > > > > + if (!is_acpi_node(fwnode)) { > > > > > > > + ov8856->xvclk = devm_clk_get(dev, "xvclk"); > > > > > > > + if (IS_ERR(ov8856->xvclk)) { > > > > > > > + dev_err(dev, "could not get xvclk clock (%pe)\n", > > > > > > > + ov8856->xvclk); > > > > > > > + return PTR_ERR(ov8856->xvclk); > > > > > > > + } > > > > > > > + > > > > > > > + clk_set_rate(ov8856->xvclk, xvclk_rate); > > > > > > > + xvclk_rate = clk_get_rate(ov8856->xvclk); > > > > > > > } > > > > > > > > > > > > Why do we handle the clock only in DT case? Is there a problem with the > > > > > > clock handling and ACPI? > > > > > > > > > > Not really, it's just that ACPI does not provide an interface to the clocks > > > > > as such. > > > > > > > > But you will get a clk by devm_clk_get()? > > > > > > No, because ACPI does not expose one to drivers. Effectively the entire > > > power sequences are implemented in ACPI, not in the driver. > > > > > > > Ah okay, thanks for the explanation. I'm really not into the ACPI > > stuff.. So this means the __power_off / power_on should only be done if > > we are using DT's? > > Correct. That's why it bails out early. It could be yet earlier though, > without doing anything. Yes I see. For easier and error less prone handling I would prefer: if (is_acpi_node()) return 0; as first instruction for __power_off/on(). Also I would refator the ov8856_check_hwcfg() so the common part can be used by this function and by a ov8856_parse_of() function. But thats only my opinion. Regards, Marco