From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964851AbaCTOoq (ORCPT ); Thu, 20 Mar 2014 10:44:46 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:10546 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933849AbaCTOon (ORCPT ); Thu, 20 Mar 2014 10:44:43 -0400 X-AuditID: cbfec7f4-b7f796d000005a13-52-532afed91a29 Message-id: <532AFED3.5030103@samsung.com> Date: Thu, 20 Mar 2014 15:44:35 +0100 From: Sylwester Nawrocki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-version: 1.0 To: Josh Wu Cc: g.liakhovetski@gmx.de, m.chehab@samsung.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [media] ov2640: add support for async device registration References: <1394791952-12941-1-git-send-email-josh.wu@atmel.com> <532371F4.9050509@gmail.com> <53296094.3060209@atmel.com> In-reply-to: <53296094.3060209@atmel.com> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrLLMWRmVeSWpSXmKPExsVy+t/xa7o3/2kFG7Tv5LV4v3Eek8Wuxt+s Fpd3zWGz6NmwldXi4jp5B1aPBb+2snh8+Bjn0bdlFaPH501yASxRXDYpqTmZZalF+nYJXBm7 F1xlLJjJVbFk12XGBsZJHF2MnBwSAiYSm99sYoWwxSQu3FvP1sXIxSEksJRRYs7D74wQzidG iYfLn7OBVPEKaEns+HEVzGYRUJX4eHkHWDebgKFE79E+RhBbVCBCYu7EzVD1ghI/Jt9jAbFF BOQlZl84BWYzC+RIvG1rZAexhQX8JH7+uwhWLyRQK/F19l+wGk4BTYm9U5YwQdTrSOxvncYG YctLbF7zlnkCo8AsJCtmISmbhaRsASPzKkbR1NLkguKk9FxDveLE3OLSvHS95PzcTYyQIP6y g3HxMatDjAIcjEo8vCv2aAYLsSaWFVfmHmKU4GBWEuG1e64VLMSbklhZlVqUH19UmpNafIiR iYNTqoHRxPBBftIUzidz+KarWy3t2ldxmFPn0wPLDpvzPLI9vXsdS9ITe6Z6i7UtTFkZddxF YE7buc+M/sGfNJnX+hsVz8hLPKDOvo+tuGXHgw2hzOXf2/ytXdVmnbjQq+o9PTlTbEFPjrL/ pQ8XGDsOXNY4avzy2NLz6k4VIUeE5PcWz1jz1lGwoEGJpTgj0VCLuag4EQC2ruvFQAIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Josh, On 19/03/14 10:17, Josh Wu wrote: > On 3/15/2014 5:17 AM, Sylwester Nawrocki wrote: >> > On 03/14/2014 11:12 AM, Josh Wu wrote: >>> >> + clk = v4l2_clk_get(&client->dev, "mclk"); >>> >> + if (IS_ERR(clk)) >>> >> + return -EPROBE_DEFER; >> > >> > You should instead make it: >> > >> > return PTR_ERR(clk); >> > >> > But you will need this patch for that to work: >> > http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/clk/clk.c?id=a34cd4666f3da84228a82f70c94b8d9b692034ea >> > >> > >> > With this patch there is no need to overwrite any returned error >> > value with EPROBE_DEFER. > > Thanks for the information. I will use this in v2 version. Oops, I missed somehow that it's v4l2_clk_get(), rather than clk_get(). So it seems it will not work when you return PTR_ERR(clk), since v4l2_clk_get() returns -ENODEV when clock is not found. I think we should modify v4l2_clk_get() so it returns EPROBE_DEFER rather than ENODEV on error. I anticipate v4l2_clk_get() might be using clk_get() internally in future, and the v4l2 clk look up will be used as a fallback only. So sensor drivers should just do something like: clk = v4l2_clk_get(...); if (IS_ERR(clk)) return PTR_ERR(clk); -- Regards, Sylwester