From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH] i2c: Hook up runtime PM support
Date: Mon, 15 Feb 2010 19:14:09 +0100
Message-ID: <20100215191409.14d87257@hyperion.delvare>
References: <1265373011-12874-1-git-send-email-broonie@opensource.wolfsonmicro.com>
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Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
To: Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
Cc: "Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>, Linux I2C <linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
List-Id: linux-i2c@vger.kernel.org

Hi Mark,

On Fri,  5 Feb 2010 12:30:11 +0000, Mark Brown wrote:
> Allow I2C drivers to make use of the runtime PM framework by adding
> bus implementations of the runtime PM operations. These simply
> immediately suspend when the device is idle. The runtime PM framework
> provides drivers with off the shelf refcounts for enables and sysfs
> control for managing runtime suspend from userspace so is useful even
> without meaningful input from the bus.
> 
> Signed-off-by: Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
> ---
> 
> Changed to allow drivers to use the idle callback to veto suspend.
> 
>  drivers/i2c/i2c-core.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 50 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 10be7b5..4131698 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -34,6 +34,7 @@
>  #include <linux/hardirq.h>
>  #include <linux/irqflags.h>
>  #include <linux/rwsem.h>
> +#include <linux/pm_runtime.h>
>  #include <asm/uaccess.h>
>  
>  #include "i2c-core.h"
> @@ -184,6 +185,52 @@ static int i2c_device_pm_resume(struct device *dev)
>  #define i2c_device_pm_resume	NULL
>  #endif
>  
> +#ifdef CONFIG_PM_RUNTIME
> +static int i2c_device_runtime_suspend(struct device *dev)
> +{
> +	const struct dev_pm_ops *pm;
> +
> +	if (!dev->driver)
> +		return 0;
> +	pm = dev->driver->pm;
> +	if (!pm || !pm->runtime_suspend)
> +		return 0;
> +	return pm->runtime_suspend(dev);
> +}
> +
> +static int i2c_device_runtime_resume(struct device *dev)
> +{
> +	const struct dev_pm_ops *pm;
> +
> +	if (!dev->driver)
> +		return 0;
> +	pm = dev->driver->pm;
> +	if (!pm || !pm->runtime_resume)
> +		return 0;
> +	return pm->runtime_resume(dev);
> +}
> +
> +static int i2c_device_runtime_idle(struct device *dev)
> +{
> +	const struct dev_pm_ops *pm = NULL;
> +	int ret;
> +
> +	if (dev->driver)
> +		pm = dev->driver->pm;
> +	if (pm && pm->runtime_idle) {
> +		ret = pm->runtime_idle(dev);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return pm_runtime_suspend(dev);
> +}
> +#else
> +#define i2c_device_runtime_suspend	NULL
> +#define i2c_device_runtime_resume	NULL
> +#define i2c_device_runtime_idle		NULL
> +#endif
> +
>  static int i2c_device_suspend(struct device *dev, pm_message_t mesg)
>  {
>  	struct i2c_client *client = i2c_verify_client(dev);
> @@ -251,6 +298,9 @@ static const struct attribute_group *i2c_dev_attr_groups[] = {
>  static const struct dev_pm_ops i2c_device_pm_ops = {
>  	.suspend = i2c_device_pm_suspend,
>  	.resume = i2c_device_pm_resume,
> +	.runtime_suspend = i2c_device_runtime_suspend,
> +	.runtime_resume = i2c_device_runtime_resume,
> +	.runtime_idle = i2c_device_runtime_idle,
>  };
>  
>  struct bus_type i2c_bus_type = {

Applied, thanks. I am a little surprised to see that these functions
have nothing i2c-specific, so I am wondering why we have to duplicate
them in every bus type... Shouldn't the functions above be part of
drivers/base/power/runtime.c and exported so that all bus types that
want them can reuse them?

-- 
Jean Delvare