clk: mpc5xxx: switch to COMMON_CLK, retire PPC_CLOCK

the setup before the change was
- arch/powerpc/Kconfig had the PPC_CLOCK option, off by default
- depending on the PPC_CLOCK option the arch/powerpc/kernel/clock.c file
  was built, which implements the clk.h API but always returns -ENOSYS
  unless a platform registers specific callbacks
- the MPC52xx platform selected PPC_CLOCK but did not register any
  callbacks, thus all clk.h API calls keep resulting in -ENOSYS errors
  (which is OK, all peripheral drivers deal with the situation)
- the MPC512x platform selected PPC_CLOCK and registered specific
  callbacks implemented in arch/powerpc/platforms/512x/clock.c, thus
  provided real support for the clock API
- no other powerpc platform did select PPC_CLOCK

the situation after the change is
- the MPC512x platform implements the COMMON_CLK interface, and thus the
  PPC_CLOCK approach in arch/powerpc/platforms/512x/clock.c has become
  obsolete
- the MPC52xx platform still lacks genuine support for the clk.h API
  while this is not a change against the previous situation (the error
  code returned from COMMON_CLK stubs differs but every call still
  results in an error)
- with all references gone, the arch/powerpc/kernel/clock.c wrapper and
  the PPC_CLOCK option have become obsolete, as did the clk_interface.h
  header file

the switch from PPC_CLOCK to COMMON_CLK is done for all platforms within
the same commit such that multiplatform kernels (the combination of 512x
and 52xx within one executable) keep working

Cc: Mike Turquette <mturquette@linaro.org>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>

arch/powerpc/Kconfig

@@ -1040,11 +1040,6 @@ config KEYS_COMPAT
 
 source "crypto/Kconfig"
 
-config PPC_CLOCK
-	bool
-	default n
-	select HAVE_CLK
-
 config PPC_LIB_RHEAP
 	bool
 

arch/powerpc/include/asm/clk_interface.h

-#ifndef __ASM_POWERPC_CLK_INTERFACE_H
-#define __ASM_POWERPC_CLK_INTERFACE_H
-
-#include <linux/clk.h>
-
-struct clk_interface {
-	struct clk*	(*clk_get)	(struct device *dev, const char *id);
-	int		(*clk_enable)	(struct clk *clk);
-	void		(*clk_disable)	(struct clk *clk);
-	unsigned long	(*clk_get_rate)	(struct clk *clk);
-	void		(*clk_put)	(struct clk *clk);
-	long		(*clk_round_rate) (struct clk *clk, unsigned long rate);
-	int 		(*clk_set_rate)	(struct clk *clk, unsigned long rate);
-	int		(*clk_set_parent) (struct clk *clk, struct clk *parent);
-	struct clk*	(*clk_get_parent) (struct clk *clk);
-};
-
-extern struct clk_interface clk_functions;
-
-#endif /* __ASM_POWERPC_CLK_INTERFACE_H */

arch/powerpc/kernel/Makefile

@@ -48,7 +48,6 @@ obj-$(CONFIG_ALTIVEC)		+= vecemu.o
 obj-$(CONFIG_PPC_970_NAP)	+= idle_power4.o
 obj-$(CONFIG_PPC_P7_NAP)	+= idle_power7.o
 obj-$(CONFIG_PPC_OF)		+= of_platform.o prom_parse.o
-obj-$(CONFIG_PPC_CLOCK)		+= clock.o
 procfs-y			:= proc_powerpc.o
 obj-$(CONFIG_PROC_FS)		+= $(procfs-y)
 rtaspci-$(CONFIG_PPC64)-$(CONFIG_PCI)	:= rtas_pci.o

arch/powerpc/kernel/clock.c

-/*
- * Dummy clk implementations for powerpc.
- * These need to be overridden in platform code.
- */
-
-#include <linux/clk.h>
-#include <linux/err.h>
-#include <linux/errno.h>
-#include <linux/export.h>
-#include <asm/clk_interface.h>
-
-struct clk_interface clk_functions;
-
-struct clk *clk_get(struct device *dev, const char *id)
-{
-	if (clk_functions.clk_get)
-		return clk_functions.clk_get(dev, id);
-	return ERR_PTR(-ENOSYS);
-}
-EXPORT_SYMBOL(clk_get);
-
-void clk_put(struct clk *clk)
-{
-	if (clk_functions.clk_put)
-		clk_functions.clk_put(clk);
-}
-EXPORT_SYMBOL(clk_put);
-
-int clk_enable(struct clk *clk)
-{
-	if (clk_functions.clk_enable)
-		return clk_functions.clk_enable(clk);
-	return -ENOSYS;
-}
-EXPORT_SYMBOL(clk_enable);
-
-void clk_disable(struct clk *clk)
-{
-	if (clk_functions.clk_disable)
-		clk_functions.clk_disable(clk);
-}
-EXPORT_SYMBOL(clk_disable);
-
-unsigned long clk_get_rate(struct clk *clk)
-{
-	if (clk_functions.clk_get_rate)
-		return clk_functions.clk_get_rate(clk);
-	return 0;
-}
-EXPORT_SYMBOL(clk_get_rate);
-
-long clk_round_rate(struct clk *clk, unsigned long rate)
-{
-	if (clk_functions.clk_round_rate)
-		return clk_functions.clk_round_rate(clk, rate);
-	return -ENOSYS;
-}
-EXPORT_SYMBOL(clk_round_rate);
-
-int clk_set_rate(struct clk *clk, unsigned long rate)
-{
-	if (clk_functions.clk_set_rate)
-		return clk_functions.clk_set_rate(clk, rate);
-	return -ENOSYS;
-}
-EXPORT_SYMBOL(clk_set_rate);
-
-struct clk *clk_get_parent(struct clk *clk)
-{
-	if (clk_functions.clk_get_parent)
-		return clk_functions.clk_get_parent(clk);
-	return ERR_PTR(-ENOSYS);
-}
-EXPORT_SYMBOL(clk_get_parent);
-
-int clk_set_parent(struct clk *clk, struct clk *parent)
-{
-	if (clk_functions.clk_set_parent)
-		return clk_functions.clk_set_parent(clk, parent);
-	return -ENOSYS;
-}
-EXPORT_SYMBOL(clk_set_parent);

arch/powerpc/platforms/512x/Kconfig

 config PPC_MPC512x
 	bool "512x-based boards"
 	depends on 6xx
+	select COMMON_CLK
 	select FSL_SOC
 	select IPIC
-	select PPC_CLOCK
 	select PPC_PCI_CHOICE
 	select FSL_PCI if PCI
 	select ARCH_WANT_OPTIONAL_GPIOLIB

arch/powerpc/platforms/512x/Makefile

 #
 # Makefile for the Freescale PowerPC 512x linux kernel.
 #
-obj-$(CONFIG_PPC_CLOCK)		+= clock.o
 obj-$(CONFIG_COMMON_CLK)	+= clock-commonclk.o
 obj-y				+= mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)	+= mpc5121_ads.o mpc5121_ads_cpld.o

arch/powerpc/platforms/52xx/Kconfig

 config PPC_MPC52xx
 	bool "52xx-based boards"
 	depends on 6xx
-	select PPC_CLOCK
+	select COMMON_CLK
 	select PPC_PCI_CHOICE
 
 config PPC_MPC5200_SIMPLE