1 files changed, 27 insertions, 4 deletions

diff --git a/include/asm-blackfin/mach-bf537/cdefBF534.h b/include/asm-blackfin/mach-bf537/cdefBF534.h
index 048d26a61fd1..82de526f8097 100644
--- a/include/asm-blackfin/mach-bf537/cdefBF534.h
+++ b/include/asm-blackfin/mach-bf537/cdefBF534.h
@@ -44,7 +44,27 @@
 
 /* Clock and System Control     (0xFFC00000 - 0xFFC000FF)                                                               */
 #define bfin_read_PLL_CTL()                  bfin_read16(PLL_CTL)
-#define bfin_write_PLL_CTL(val)              bfin_write16(PLL_CTL,val)
+/* Writing to PLL_CTL initiates a PLL relock sequence. */
+static __inline__ void bfin_write_PLL_CTL(unsigned int val)
+{
+        unsigned long flags, iwr;
+
+        if (val == bfin_read_PLL_CTL())
+                return;
+
+        local_irq_save(flags);
+        /* Enable the PLL Wakeup bit in SIC IWR */
+        iwr = bfin_read32(SIC_IWR);
+        /* Only allow PPL Wakeup) */
+        bfin_write32(SIC_IWR, IWR_ENABLE(0));
+
+        bfin_write16(PLL_CTL, val);
+        SSYNC();
+        asm("IDLE;");
+
+        bfin_write32(SIC_IWR, iwr);
+        local_irq_restore(flags);
+}
 #define bfin_read_PLL_DIV()                  bfin_read16(PLL_DIV)
 #define bfin_write_PLL_DIV(val)              bfin_write16(PLL_DIV,val)
 #define bfin_read_VR_CTL()                   bfin_read16(VR_CTL)
@@ -53,6 +73,10 @@ static __inline__ void bfin_write_VR_CTL(unsigned int val)
 {
         unsigned long flags, iwr;
 
+        if (val == bfin_read_VR_CTL())
+                return;
+
+        local_irq_save(flags);
         /* Enable the PLL Wakeup bit in SIC IWR */
         iwr = bfin_read32(SIC_IWR);
         /* Only allow PPL Wakeup) */
@@ -60,11 +84,10 @@ static __inline__ void bfin_write_VR_CTL(unsigned int val)
 
         bfin_write16(VR_CTL, val);
         SSYNC();
-
-        local_irq_save(flags);
         asm("IDLE;");
-        local_irq_restore(flags);
+
         bfin_write32(SIC_IWR, iwr);
+        local_irq_restore(flags);
 }
 #define bfin_read_PLL_STAT()                 bfin_read16(PLL_STAT)
 #define bfin_write_PLL_STAT(val)             bfin_write16(PLL_STAT,val)