Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755770Ab3ILWGL (ORCPT ); Thu, 12 Sep 2013 18:06:11 -0400 Received: from mail-ea0-f178.google.com ([209.85.215.178]:55468 "EHLO mail-ea0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229Ab3ILWGG (ORCPT ); Thu, 12 Sep 2013 18:06:06 -0400 Message-ID: <52323AC8.30403@gmail.com> Date: Fri, 13 Sep 2013 00:06:00 +0200 From: Sylwester Nawrocki User-Agent: Mozilla/5.0 (X11; Linux i686; rv:11.0) Gecko/20120412 Thunderbird/11.0.1 MIME-Version: 1.0 To: Mika Westerberg CC: linux-i2c@vger.kernel.org, Wolfram Sang , "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Lv Zheng , Aaron Lu , linux-arm-kernel@lists.infradead.org, Mark Brown , Dmitry Torokhov , Mauro Carvalho Chehab , Samuel Ortiz , Lee Jones , Arnd Bergmann , Greg Kroah-Hartman , Liam Girdwood , Kyungmin Park Subject: Re: [PATCH v2 1/9] i2c: prepare runtime PM support for I2C client devices References: <1378913560-2752-1-git-send-email-mika.westerberg@linux.intel.com> <1378913560-2752-2-git-send-email-mika.westerberg@linux.intel.com> In-Reply-To: <1378913560-2752-2-git-send-email-mika.westerberg@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2233 Lines: 56 On 09/11/2013 05:32 PM, Mika Westerberg wrote: > From: Aaron Lu > > This patch adds runtime PM support for the I2C bus in a similar way that > has been done for PCI bus already. This means that the I2C bus core > prepares runtime PM for a client device just before a driver is about to be > bound to it. Devices that are not bound to any driver are not prepared for > runtime PM. > > In order to take advantage of this runtime PM support, the client device > driver needs drop the device runtime PM reference count by calling > pm_runtime_put() in its ->probe() callback and possibly implement rest of > the runtime PM callbacks. > > If the driver doesn't support runtime PM (like most of the existing I2C > client drivers), the device in question is regarded as being runtime PM > active and powered on. > > The patch adds also runtime PM support for the adapter device because it is > needed to be able to runtime power manage the I2C controller device. The > adapter device is handled along with the I2C controller device (it uses > pm_runtime_no_callbacks()). > > Signed-off-by: Aaron Lu > Signed-off-by: Mika Westerberg > --- > drivers/i2c/i2c-core.c | 44 +++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 43 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index f32ca29..44374b4 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -248,11 +248,30 @@ static int i2c_device_probe(struct device *dev) > client->flags& I2C_CLIENT_WAKE); > dev_dbg(dev, "probe\n"); > > + /* Make sure the adapter is active */ > + pm_runtime_get_sync(&client->adapter->dev); So there is currently no way to avoid this behaviour, i.e. to have the adapter not activated before any of its client devices is probed, but only later on, after explicit call to pm_runtime_get*(&client->dev) in the client driver ? -- Thanks, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/