Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754889AbdIRN0y (ORCPT ); Mon, 18 Sep 2017 09:26:54 -0400 Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:47304 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752377AbdIRN0w (ORCPT ); Mon, 18 Sep 2017 09:26:52 -0400 Date: Mon, 18 Sep 2017 16:26:49 +0300 From: Sakari Ailus To: "Yang, Wenyou" Cc: Jonathan Corbet , Nicolas Ferre , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Linux Media Mailing List , Mauro Carvalho Chehab Subject: Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation Message-ID: <20170918132649.njqvbs3zq6b5iuej@valkosipuli.retiisi.org.uk> References: <20170918064514.6841-1-wenyou.yang@microchip.com> <20170918064514.6841-4-wenyou.yang@microchip.com> <20170918073529.wssxfbgfwgd2jzpl@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 33 Hi Wenyou, On Mon, Sep 18, 2017 at 05:26:16PM +0800, Yang, Wenyou wrote: > Hi Sakari, > > > On 2017/9/18 15:35, Sakari Ailus wrote: > > Hi Wenyou, > > > > Thanks for the update. > > > > The driver exposes controls that are accessible through the sub-device node > > even if the device hasn't been powered on. > > > > Many ISP and bridge drivers will also power the sensor down once the last > > user of the user space device nodes disappears. You could keep the device > > powered at all times or change the behaviour so that controls can be > > accessed when the power is off. > > > > The best option would be to convert the driver to use runtime PM. > Yes, I agree with you. > I also noticed there are a lot of things needed to improve except for it, > such as the platform data via device tree. > I would like do it in another patch set. I will continue to work on it. Adding runtime PM support later on sound good to me. > > An example of this can be found in drivers/media/i2c/ov13858.c . > A good example, thank you for your providing. -- Sakari Ailus e-mail: sakari.ailus@iki.fi