On 27 February 2014 00:00, Kevin Hilman [off-list ref] wrote:

Ulf Hansson [off-list ref] writes:

quoted

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 <redacted>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Russell King <redacted>
Cc: Linus Walleij <redacted>
Cc: Wolfram Sang <redacted>
Cc: Alessandro Rubini <redacted>
Signed-off-by: Ulf Hansson <redacted>
---

Changes in v2:
      Updated the macro to return a callback instead.
      Suggested by Josh Cartwright.

---
 drivers/base/power/runtime.c |   63 ++++++++++++++++--------------------------
 1 file changed, 24 insertions(+), 39 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 72e00e6..cc7d1ed 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c

@@ -13,6 +13,27 @@
 #include <trace/events/rpm.h>
 #include "power.h"

+#define RPM_GET_CALLBACK(dev, cb)                            \
+({                                                           \
+     int (*__rpm_cb)(struct device *__d);                    \
+                                                             \
+     if (dev->pm_domain)                                     \
+             __rpm_cb = dev->pm_domain->ops.cb;              \
+     else if (dev->type && dev->type->pm)                    \
+             __rpm_cb = dev->type->pm->cb;                   \
+     else if (dev->class && dev->class->pm)                  \
+             __rpm_cb = dev->class->pm->cb;                  \
+     else if (dev->bus && dev->bus->pm)                      \
+             __rpm_cb = dev->bus->pm->cb;                    \
+     else                                                    \
+             __rpm_cb = NULL;                                \
+                                                             \
+     if (!__rpm_cb && dev->driver && dev->driver->pm)        \
+             __rpm_cb = dev->driver->pm->cb;                 \
+                                                             \
+     __rpm_cb;                                               \
+})

So the main question from v1 remains: why use a macro, and not a function?

I am no big fan of macros, but in this case I thought it make sense.
Using _a_ function would not be enough, since we would need three, one
for each runtime PM callback (suspend, idle, resume), right?

I am happy to change to whatever you guys thinks best, I have no strong opinion.

Kind regards
Uffe

Kevin