From 7653c318b73d8553d4c13bb7e371878ddc19f80d Mon Sep 17 00:00:00 2001
From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Date: Thu, 28 Feb 2013 13:21:58 +0100
Subject: [PATCH] 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>
---
arch/arm/mach-shmobile/clock-sh73a0.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-shmobile/clock-sh73a0.c b/arch/arm/mach-shmobile/clock-sh73a0.c
index 71843dd39e16a..34b5c5ae4cbdb 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 @@ static struct clk *main_clks[] = {
&sh73a0_extalr_clk,
};
-static void div4_kick(struct clk *clk)
+static int frqcr_kick(void)
{
- unsigned long value;
+ 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;
+}
- /* set KICK bit in FRQCRB to update hardware setting */
- value = __raw_readl(FRQCRB);
- value |= (1 << 31);
- __raw_writel(value, FRQCRB);
+static void div4_kick(struct clk *clk)
+{
+ frqcr_kick();
}
static int divisors[] = { 2, 3, 4, 6, 8, 12, 16, 18,
--
2.30.2