[PATCH 1/8] PM / Runtime: Fetch runtime PM callbacks using a macro

[Kevin Hilman]

Ulf Hansson <ulf.hansson at linaro.org> writes:

> While fetching the proper runtime PM callback, we walk the hierarchy of
> device's power domains, subsystems and drivers.
>
> This is common for rpm_suspend(), rpm_idle() and rpm_resume(). Let's
> clean up the code by using a macro that handles this.
>
> Cc: Kevin Hilman <khilman at linaro.org>
> Cc: Alan Stern <stern at rowland.harvard.edu>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Russell King <linux at arm.linux.org.uk>
> Cc: Linus Walleij <linus.walleij at linaro.org>
> Cc: Wolfram Sang <wsa at the-dreams.de>
> Cc: Alessandro Rubini <rubini at unipv.it>
> Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
> ---
>  drivers/base/power/runtime.c |   59 ++++++++++++++----------------------------
>  1 file changed, 20 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 72e00e6..dedbd64 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -13,6 +13,23 @@
>  #include <trace/events/rpm.h>
>  #include "power.h"
>  
> +#define RPM_GET_CALLBACK(dev, cb)				\
> +({								\
> +	if (dev->pm_domain)					\
> +		callback = dev->pm_domain->ops.cb;		\
> +	else if (dev->type && dev->type->pm)			\
> +		callback = dev->type->pm->cb;			\
> +	else if (dev->class && dev->class->pm)			\
> +		callback = dev->class->pm->cb;			\
> +	else if (dev->bus && dev->bus->pm)			\
> +		callback = dev->bus->pm->cb;			\
> +	else							\
> +		callback = NULL;				\
> +								\
> +	if (!callback && dev->driver && dev->driver->pm)	\
> +		callback = dev->driver->pm->cb;			\
> +})
> +
>  static int rpm_resume(struct device *dev, int rpmflags);
>  static int rpm_suspend(struct device *dev, int rpmflags);
>  
> @@ -310,19 +327,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
>  
>  	dev->power.idle_notification = true;
>  
> -	if (dev->pm_domain)
> -		callback = dev->pm_domain->ops.runtime_idle;
> -	else if (dev->type && dev->type->pm)
> -		callback = dev->type->pm->runtime_idle;
> -	else if (dev->class && dev->class->pm)
> -		callback = dev->class->pm->runtime_idle;
> -	else if (dev->bus && dev->bus->pm)
> -		callback = dev->bus->pm->runtime_idle;
> -	else
> -		callback = NULL;
> -
> -	if (!callback && dev->driver && dev->driver->pm)
> -		callback = dev->driver->pm->runtime_idle;
> +	RPM_GET_CALLBACK(dev, runtime_idle);

This macro sets the local 'callback' variable, but it's not at all
obvious when reading the code.  macros with side-effects like this are a
major readability problem.  Just use a function.

Kevin