ARM: OMAP3/4: consolidate cpuidle Makefile

The current Makefile compiles the cpuidle34xx.c and cpuidle44xx.c files
even if the cpuidle option is not set in the kernel.

This patch fixes this by creating a section in the Makefile where these
files are compiled only if the CONFIG_CPU_IDLE option is set.

This modification breaks an implicit dependency between CPU_IDLE and PM as
they belong to the same block in the Makefile. This is fixed in the Kconfig
by selecting explicitely PM is CPU_IDLE is set.

The linux coding style recommend to use no-op functions in the headers
when the subsystem is disabled instead of adding big section in C files.

This patch fix this also.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/Kconfig

@@ -35,6 +35,7 @@ config ARCH_OMAP3
 	select CPU_V7
 	select USB_ARCH_HAS_EHCI if USB_SUPPORT
 	select ARCH_HAS_OPP
+	select PM if CPU_IDLE
 	select PM_OPP if PM
 	select ARM_CPU_SUSPEND if PM
 	select MULTI_IRQ_HANDLER
@@ -52,6 +53,7 @@ config ARCH_OMAP4
 	select PL310_ERRATA_727915
 	select ARM_ERRATA_720789
 	select ARCH_HAS_OPP
+	select PM if CPU_IDLE
 	select PM_OPP if PM
 	select USB_ARCH_HAS_EHCI if USB_SUPPORT
 	select ARM_CPU_SUSPEND if PM

arch/arm/mach-omap2/Makefile

@@ -66,9 +66,7 @@ ifeq ($(CONFIG_PM),y)
 obj-$(CONFIG_ARCH_OMAP2)		+= pm24xx.o
 obj-$(CONFIG_ARCH_OMAP2)		+= sleep24xx.o
 obj-$(CONFIG_ARCH_OMAP3)		+= pm34xx.o sleep34xx.o
-obj-$(CONFIG_ARCH_OMAP3)		+= cpuidle34xx.o
 obj-$(CONFIG_ARCH_OMAP4)		+= pm44xx.o omap-mpuss-lowpower.o
-obj-$(CONFIG_ARCH_OMAP4)		+= cpuidle44xx.o
 obj-$(CONFIG_PM_DEBUG)			+= pm-debug.o
 obj-$(CONFIG_OMAP_SMARTREFLEX)          += sr_device.o smartreflex.o
 obj-$(CONFIG_OMAP_SMARTREFLEX_CLASS3)	+= smartreflex-class3.o
@@ -82,6 +80,11 @@ endif
 
 endif
 
+ifeq ($(CONFIG_CPU_IDLE),y)
+obj-$(CONFIG_ARCH_OMAP3)                += cpuidle34xx.o
+obj-$(CONFIG_ARCH_OMAP4)                += cpuidle44xx.o
+endif
+
 # PRCM
 obj-y					+= prm_common.o
 obj-$(CONFIG_ARCH_OMAP2)		+= prcm.o cm2xxx_3xxx.o prm2xxx_3xxx.o

arch/arm/mach-omap2/cpuidle34xx.c

@@ -36,8 +36,6 @@
 #include "control.h"
 #include "common.h"
 
-#ifdef CONFIG_CPU_IDLE
-
 /* Mach specific information to be recorded in the C-state driver_data */
 struct omap3_idle_statedata {
 	u32 mpu_state;
@@ -379,9 +377,3 @@ int __init omap3_idle_init(void)
 
 	return 0;
 }
-#else
-int __init omap3_idle_init(void)
-{
-	return 0;
-}
-#endif /* CONFIG_CPU_IDLE */

arch/arm/mach-omap2/cpuidle44xx.c

@@ -22,8 +22,6 @@
 #include "pm.h"
 #include "prm.h"
 
-#ifdef CONFIG_CPU_IDLE
-
 /* Machine specific information */
 struct omap4_idle_statedata {
 	u32 cpu_state;
@@ -199,9 +197,3 @@ int __init omap4_idle_init(void)
 
 	return 0;
 }
-#else
-int __init omap4_idle_init(void)
-{
-	return 0;
-}
-#endif /* CONFIG_CPU_IDLE */

arch/arm/mach-omap2/pm.h

@@ -15,12 +15,25 @@
 
 #include "powerdomain.h"
 
+#ifdef CONFIG_CPU_IDLE
+extern int __init omap3_idle_init(void);
+extern int __init omap4_idle_init(void);
+#else
+static inline int omap3_idle_init(void)
+{
+	return 0;
+}
+
+static inline int omap4_idle_init(void)
+{
+	return 0;
+}
+#endif
+
 extern void *omap3_secure_ram_storage;
 extern void omap3_pm_off_mode_enable(int);
 extern void omap_sram_idle(void);
 extern int omap_set_pwrdm_state(struct powerdomain *pwrdm, u32 state);
-extern int omap3_idle_init(void);
-extern int omap4_idle_init(void);
 extern int omap_pm_clkdms_setup(struct clockdomain *clkdm, void *unused);
 extern int (*omap_pm_suspend)(void);