linux-kernel - Re: [PATCH v3] i2c: enable runtime PM for I2C adapter devices enumerated from ACPI

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Message-ID: <20130930185907.GS28875@intel.com>
Date:	Mon, 30 Sep 2013 21:59:07 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	linux-i2c@...r.kernel.org, Wolfram Sang <wsa@...-dreams.de>,
	Aaron Lu <aaron.lu@...el.com>, Lv Zheng <lv.zheng@...el.com>,
	Mark Brown <broonie@...nel.org>,
	Kevin Hilman <khilman@...aro.org>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-acpi@...r.kernel.org
Subject: Re: [PATCH v3] i2c: enable runtime PM for I2C adapter devices
 enumerated from ACPI

On Mon, Sep 30, 2013 at 07:20:59PM +0200, Rafael J. Wysocki wrote:
> > +static void acpi_i2c_device_pm_get(struct i2c_client *client)
> > +{
> > +	struct i2c_adapter *adap = client->adapter;
> > +
> > +	/* Make sure the adapter is active */
> > +	if (ACPI_HANDLE(adap->dev.parent))
> > +		pm_runtime_get_sync(&adap->dev);
> > +	if (ACPI_HANDLE(&client->dev))
> > +		acpi_dev_pm_attach(&client->dev, true);
> 
> It would be sufficient to do
> 
> 	if (ACPI_HANDLE(&client->dev)) {
> 		pm_runtime_get_sync(&adap->dev);
> 		acpi_dev_pm_attach(&client->dev, true);
> 	}
> 
> here (and below), because I don't think the client with an ACPI handle and the
> parent without one is extremely unlikely (to the point of non-existence
> actually ;-)).  And even if something like that happens, then we only enable
> runtime PM for the adapter if the parent has an ACPI handle, so it still should
> be OK.

OK, I'll change that in the next revision. 

> Apart from this the patch looks good to me.

Thanks!
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