ARM: shmobile: sh73a0: wait for completion when kicking the clock
To reconfigure clocks, controlled by FRQCRA and FRQCRB, a kick bit has to
be set and to make sure the setting has taken effect, it has to be read
back repeatedly until it is cleared by the hardware. This patch adds the
waiting part, that was missing until now.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Magnus Damm <damm@opensource.se
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/arch/arm/mach-shmobile/clock-sh73a0.c b/arch/arm/mach-shmobile/clock-sh73a0.c
index 71843dd..34b5c5a 100644
--- a/arch/arm/mach-shmobile/clock-sh73a0.c
+++ b/arch/arm/mach-shmobile/clock-sh73a0.c
@@ -21,6 +21,7 @@
#include <linux/io.h>
#include <linux/sh_clk.h>
#include <linux/clkdev.h>
+#include <asm/processor.h>
#include <mach/common.h>
#define FRQCRA IOMEM(0xe6150000)
@@ -234,14 +235,24 @@
&sh73a0_extalr_clk,
};
+static int frqcr_kick(void)
+{
+ int i;
+
+ /* set KICK bit in FRQCRB to update hardware setting, check success */
+ __raw_writel(__raw_readl(FRQCRB) | (1 << 31), FRQCRB);
+ for (i = 1000; i; i--)
+ if (__raw_readl(FRQCRB) & (1 << 31))
+ cpu_relax();
+ else
+ return i;
+
+ return -ETIMEDOUT;
+}
+
static void div4_kick(struct clk *clk)
{
- unsigned long value;
-
- /* set KICK bit in FRQCRB to update hardware setting */
- value = __raw_readl(FRQCRB);
- value |= (1 << 31);
- __raw_writel(value, FRQCRB);
+ frqcr_kick();
}
static int divisors[] = { 2, 3, 4, 6, 8, 12, 16, 18,