mips: ralink: convert to CONFIG_COMMON_CLK

ralink only has a very trivial clock implementation, with everything
being fixed clocks.

Convert it to CONFIG_COMMON_CLK to reduce the number of platforms
that rely on legacy clocks. Of course, the clocks really should
be read from the device tree instead, but this is a step into that
direction.

This adds about 50KB to the kernel image size, which is an unfortunate
increase, but not as bad as I had feared:

   text	   data	    bss	    dec	    hex	filename
3778560	1582216	  92256	5453032	 5334e8	vmlinux-vocore-before
3822148	1601192	  92304	5515644	 54297c	vmlinux-vocore-after
3870226	1644468	 200192	5714886	 5733c6	vmlinux-rt305x-before
3916727	1668404	 200240	5785371	 58471b	vmlinux-rt305x-after

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/mips/Kconfig

@@ -630,6 +630,7 @@ config MACH_NINTENDO64
 config RALINK
 	bool "Ralink based machines"
 	select CEVT_R4K
+	select COMMON_CLK
 	select CSRC_R4K
 	select BOOT_RAW
 	select DMA_NONCOHERENT

arch/mips/ralink/Kconfig

@@ -28,22 +28,18 @@ choice
 		bool "RT288x"
 		select MIPS_AUTO_PFN_OFFSET
 		select MIPS_L1_CACHE_SHIFT_4
-		select HAVE_LEGACY_CLK
 		select HAVE_PCI
 
 	config SOC_RT305X
 		bool "RT305x"
-		select HAVE_LEGACY_CLK
 
 	config SOC_RT3883
 		bool "RT3883"
-		select HAVE_LEGACY_CLK
 		select HAVE_PCI
 
 	config SOC_MT7620
 		bool "MT7620/8"
 		select CPU_MIPSR2_IRQ_VI
-		select HAVE_LEGACY_CLK
 		select HAVE_PCI
 
 	config SOC_MT7621
@@ -54,7 +50,6 @@ choice
 		select SYS_SUPPORTS_MIPS_CPS
 		select SYS_SUPPORTS_HIGHMEM
 		select MIPS_GIC
-		select COMMON_CLK
 		select CLKSRC_MIPS_GIC
 		select HAVE_PCI if PCI_MT7621
 		select SOC_BUS

arch/mips/ralink/clk.c

@@ -10,80 +10,22 @@
 #include <linux/export.h>
 #include <linux/clkdev.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 
 #include <asm/time.h>
 
 #include "common.h"
 
-struct clk {
-	struct clk_lookup cl;
-	unsigned long rate;
-};
-
 void ralink_clk_add(const char *dev, unsigned long rate)
 {
-	struct clk *clk = kzalloc(sizeof(struct clk), GFP_KERNEL);
+	struct clk *clk = clk_register_fixed_rate(NULL, dev, NULL, 0, rate);
 
 	if (!clk)
 		panic("failed to add clock");
 
-	clk->cl.dev_id = dev;
-	clk->cl.clk = clk;
-
-	clk->rate = rate;
-
-	clkdev_add(&clk->cl);
+	clkdev_create(clk, NULL, "%s", dev);
 }
 
-/*
- * Linux clock API
- */
-int clk_enable(struct clk *clk)
-{
-	return 0;
-}
-EXPORT_SYMBOL_GPL(clk_enable);
-
-void clk_disable(struct clk *clk)
-{
-}
-EXPORT_SYMBOL_GPL(clk_disable);
-
-unsigned long clk_get_rate(struct clk *clk)
-{
-	if (!clk)
-		return 0;
-
-	return clk->rate;
-}
-EXPORT_SYMBOL_GPL(clk_get_rate);
-
-int clk_set_rate(struct clk *clk, unsigned long rate)
-{
-	return -1;
-}
-EXPORT_SYMBOL_GPL(clk_set_rate);
-
-long clk_round_rate(struct clk *clk, unsigned long rate)
-{
-	return -1;
-}
-EXPORT_SYMBOL_GPL(clk_round_rate);
-
-int clk_set_parent(struct clk *clk, struct clk *parent)
-{
-	WARN_ON(clk);
-	return -1;
-}
-EXPORT_SYMBOL_GPL(clk_set_parent);
-
-struct clk *clk_get_parent(struct clk *clk)
-{
-	WARN_ON(clk);
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(clk_get_parent);
-
 void __init plat_time_init(void)
 {
 	struct clk *clk;