[PATCH v2 2/4] clk: renesas: rcar-gen3-cpg: add spinlock

[Sergei Shtylyov]

Protect the CPG register read-modify-write sequence with a spinlock.

Signed-off-by: Sergei Shtylyov <sergei.shtyl...@cogentembedded.com>

---
Changes in version 2:
- new patch.

 drivers/clk/renesas/rcar-gen3-cpg.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Index: renesas-drivers/drivers/clk/renesas/rcar-gen3-cpg.c
===================================================================
--- renesas-drivers.orig/drivers/clk/renesas/rcar-gen3-cpg.c
+++ renesas-drivers/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -30,14 +30,19 @@
 
 #define CPG_RCKCR_CKSEL        BIT(15) /* RCLK Clock Source Select */
 
+static spinlock_t cpg_lock;
+
 static void cpg_reg_modify(void __iomem *reg, u32 clear, u32 set)
 {
+       unsigned long flags;
        u32 val;
 
+       spin_lock_irqsave(&cpg_lock, flags);
        val = readl(reg);
        val &= ~clear;
        val |= set;
        writel(val, reg);
+       spin_unlock_irqrestore(&cpg_lock, flags);
 };
 
 struct cpg_simple_notifier {
@@ -604,5 +609,8 @@ int __init rcar_gen3_cpg_init(const stru
        if (attr)
                cpg_quirks = (uintptr_t)attr->data;
        pr_debug("%s: mode = 0x%x quirks = 0x%x\n", __func__, mode, cpg_quirks);
+
+       spin_lock_init(&cpg_lock);
+
        return 0;
 }