Subject: [PATCH] PM / Domains: Change prototype for the ->attach_dev() callback

From: [email-masked] (Kevin Hilman)
Date: Wed, 05 Nov 2014 14:43:31 -0800

Dmitry Torokhov <[email-masked]> writes:

> On Thu, Oct 30, 2014 at 01:38:30PM -0700, Kevin Hilman wrote:
>> "Rafael J. Wysocki" <[email-masked]> writes:
>> 
>> > On Thursday, October 30, 2014 01:02:49 PM Ulf Hansson wrote:
>> >> Convert the prototype to return and int. This is just an initial step,
>> >> needed to support error handling.
>> >> 
>> >> Signed-off-by: Ulf Hansson <[email-masked]>
>> 
>> Acked-by: Kevin Hilman <[email-masked]>
>> 
>> >> 
>> >> This patch is intended as fix for 3.18 rc[n]. Why?
>> >> 
>> >> There are other SOC specific patches around that adds genpd support and which
>> >> implements the ->attach_dev() callback. To prevent having an "atomic" patch
>> >> during the next release cycle, let's change the prototype now instead.
>> >> 
>> >> Further patches will add the actual error handling in genpd and these can then
>> >> be reviewed and tested thoroughly.
>> >
>> > So we have no users of ->attach_dev at the moment, right?
>> 
>> Not in mainline, but there are a couple getting ready to hit -next, so
>> we wanted to fix this before they arrive so that adding the error
>> handling will be easier.
>
> BTW, while we are at it, can we also pass the domain itself to
> attach_dev() and detach_dev()? If anything it helps with debugging (you
> can print domain name from the callbacks).

Agreed, and it makes it match the other callbacks (power_off, power_on)
which currently take struct generic_pm_domain *domain.  

Updated version of $SUBJECT patch below.

Kevin

----- >8 ------
>>From 353a62ffae2f9228142c8a2093108f9eda8dc6b4 Mon Sep 17 00:00:00 2001
From: Ulf Hansson <[email-masked]>
Date: Thu, 30 Oct 2014 13:02:49 +0100
Subject: [PATCH] PM / Domains: Change prototype for the ->attach_dev()
 callback

Convert the prototype to return and int. This is just an initial step,
needed to support error handling.

Cc: Dmitry Torokhov <[email-masked]>
[khilman: added domain as parameter to callbacks, as suggested by Dmitry]
Signed-off-by: Ulf Hansson <[email-masked]>
Signed-off-by: Kevin Hilman <[email-masked]>
---
 drivers/base/power/domain.c | 4 ++--
 include/linux/pm_domain.h   | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 40bc2f4072cc..b520687046d4 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1437,7 +1437,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	spin_unlock_irq(&dev->power.lock);
 
 	if (genpd->attach_dev)
-		genpd->attach_dev(dev);
+		genpd->attach_dev(genpd, dev);
 
 	mutex_lock(&gpd_data->lock);
 	gpd_data->base.dev = dev;
@@ -1499,7 +1499,7 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	genpd->max_off_time_changed = true;
 
 	if (genpd->detach_dev)
-		genpd->detach_dev(dev);
+		genpd->detach_dev(genpd, dev);
 
 	spin_lock_irq(&dev->power.lock);
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 73e938b7e937..b3ed7766a291 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -72,8 +72,10 @@ struct generic_pm_domain {
 	bool max_off_time_changed;
 	bool cached_power_down_ok;
 	struct gpd_cpuidle_data *cpuidle_data;
-	void (*attach_dev)(struct device *dev);
-	void (*detach_dev)(struct device *dev);
+	int (*attach_dev)(struct generic_pm_domain *domain,
+			  struct device *dev);
+	void (*detach_dev)(struct generic_pm_domain *domain,
+			   struct device *dev);
 };
 
 static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
-- 
2.1.0