[PATCH] ARM: iMX5: Don't enable DPLL if it already enabled

[Jason Liu]

If the DPLL is already enabled, don't try to enable it again.
Since write to the DPLL control register will make the DPLL
reset and which will cause some issues when some child module
are sourced from this DPLL.

Signed-off-by: Jason Liu <jason.hui at linaro.org>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/mach-mx5/clock-mx51-mx53.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-mx5/clock-mx51-mx53.c b/arch/arm/mach-mx5/clock-mx51-mx53.c
index 7f20308..f7bf996 100644
--- a/arch/arm/mach-mx5/clock-mx51-mx53.c
+++ b/arch/arm/mach-mx5/clock-mx51-mx53.c
@@ -271,7 +271,11 @@ static int _clk_pll_enable(struct clk *clk)
 	int i = 0;
 
 	pllbase = _get_pll_base(clk);
-	reg = __raw_readl(pllbase + MXC_PLL_DP_CTL) | MXC_PLL_DP_CTL_UPEN;
+	reg = __raw_readl(pllbase + MXC_PLL_DP_CTL);
+	if (reg & MXC_PLL_DP_CTL_UPEN)
+		return 0;
+
+	reg |= MXC_PLL_DP_CTL_UPEN;
 	__raw_writel(reg, pllbase + MXC_PLL_DP_CTL);
 
 	/* Wait for lock */
-- 
1.7.0.4