ARM: 6145/1: ux500 MTU clockrate correction

This adjusts the clockrate for the MTU timer. On the different
UX500 variants this rate is different. The platform can also have
been set up at hardware initialization, bootloader or early init
for different clock speeds. To have the clock framework available
early so the timers can use them, the clock initialization for
Nomadik and ux500 is moved to IRQ init time. A custom per-clock
callback is added to handle special cases like this.

This solves a user-visible bug: without this patch the current
UX500 platforms will not be synchronized to wall-clock time and
the platform will drift in time.

Acked-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 17 insertions, 4 deletions

diff --git a/arch/arm/mach-nomadik/clock.c b/arch/arm/mach-nomadik/clock.c
index 2c471fc451d7..f035f4185274 100644
--- a/arch/arm/mach-nomadik/clock.c
+++ b/arch/arm/mach-nomadik/clock.c
@@ -32,7 +32,10 @@ void clk_disable(struct clk *clk)
 }
 EXPORT_SYMBOL(clk_disable);
 
-/* We have a fixed clock alone, for now */
+static struct clk clk_24 = {
+	.rate = 2400000,
+};
+
 static struct clk clk_48 = {
 	.rate = 48 * 1000 * 1000,
 };
@@ -50,6 +53,8 @@ static struct clk clk_default;
 	}
 
 static struct clk_lookup lookups[] = {
+	CLK(&clk_24, "mtu0"),
+	CLK(&clk_24, "mtu1"),
 	CLK(&clk_48, "uart0"),
 	CLK(&clk_48, "uart1"),
 	CLK(&clk_default, "gpio.0"),
@@ -59,10 +64,8 @@ static struct clk_lookup lookups[] = {
 	CLK(&clk_default, "rng"),
 };
 
-static int __init clk_init(void)
+int __init clk_init(void)
 {
 	clkdev_add_table(lookups, ARRAY_SIZE(lookups));
 	return 0;
 }
-
-arch_initcall(clk_init);
diff --git a/arch/arm/mach-nomadik/clock.h b/arch/arm/mach-nomadik/clock.h
index 5563985a2cc7..78da2e7c3985 100644
--- a/arch/arm/mach-nomadik/clock.h
+++ b/arch/arm/mach-nomadik/clock.h
@@ -11,3 +11,5 @@
 struct clk {
 	unsigned long		rate;
 };
+
+int __init clk_init(void);
diff --git a/arch/arm/mach-nomadik/cpu-8815.c b/arch/arm/mach-nomadik/cpu-8815.c
index 91c3c901b469..ac58e3b03b1a 100644
--- a/arch/arm/mach-nomadik/cpu-8815.c
+++ b/arch/arm/mach-nomadik/cpu-8815.c
@@ -31,6 +31,8 @@
 #include <asm/cacheflush.h>
 #include <asm/hardware/cache-l2x0.h>
 
+#include "clock.h"
+
 #define __MEM_4K_RESOURCE(x) \
 	.res = {.start = (x), .end = (x) + SZ_4K - 1, .flags = IORESOURCE_MEM}
 
@@ -143,6 +145,12 @@ void __init cpu8815_init_irq(void)
 	/* This modified VIC cell has two register blocks, at 0 and 0x20 */
 	vic_init(io_p2v(NOMADIK_IC_BASE + 0x00), IRQ_VIC_START +  0, ~0, 0);
 	vic_init(io_p2v(NOMADIK_IC_BASE + 0x20), IRQ_VIC_START + 32, ~0, 0);
+
+	/*
+	 * Init clocks here so that they are available for system timer
+	 * initialization.
+	 */
+	clk_init();
 }
 
 /*