[PATCH v2 1/3] clk: ti: add a usecount for autoidle

[Andreas Kemnade]

Multiple users might deny autoidle on a clock. So we should have some
counting here, also according to the comment in  _setup_iclk_autoidle().
Also setting autoidle regs is not atomic, so there is another reason
for locking.

Signed-off-by: Andreas Kemnade <andr...@kemnade.info>
---
Changes since v1:
- use spinlocks instead of mutexes
- invert logic
---
 drivers/clk/ti/autoidle.c | 36 ++++++++++++++++++++++++++++--------
 include/linux/clk/ti.h    |  1 +
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
index 7bb9afbe4058..161f67850393 100644
--- a/drivers/clk/ti/autoidle.c
+++ b/drivers/clk/ti/autoidle.c
@@ -37,6 +37,14 @@ struct clk_ti_autoidle {
 static LIST_HEAD(autoidle_clks);
 static LIST_HEAD(clk_hw_omap_clocks);
 
+/*
+ * we have some non-atomic read/write
+ * operations behind it, so lets
+ * take one lock for handling autoidle
+ * of all clocks
+ */
+static DEFINE_SPINLOCK(autoidle_spinlock);
+
 /**
  * omap2_clk_deny_idle - disable autoidle on an OMAP clock
  * @clk: struct clk * to disable autoidle for
@@ -48,8 +56,15 @@ int omap2_clk_deny_idle(struct clk *clk)
        struct clk_hw_omap *c;
 
        c = to_clk_hw_omap(__clk_get_hw(clk));
-       if (c->ops && c->ops->deny_idle)
-               c->ops->deny_idle(c);
+       if (c->ops && c->ops->deny_idle) {
+               unsigned long irqflags;
+
+               spin_lock_irqsave(&autoidle_spinlock, irqflags);
+               c->autoidle_count++;
+               if (c->autoidle_count == 1)
+                       c->ops->deny_idle(c);
+               spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
+       }
        return 0;
 }
 
@@ -64,8 +79,15 @@ int omap2_clk_allow_idle(struct clk *clk)
        struct clk_hw_omap *c;
 
        c = to_clk_hw_omap(__clk_get_hw(clk));
-       if (c->ops && c->ops->allow_idle)
-               c->ops->allow_idle(c);
+       if (c->ops && c->ops->allow_idle) {
+               unsigned long irqflags;
+
+               spin_lock_irqsave(&autoidle_spinlock, irqflags);
+               c->autoidle_count--;
+               if (c->autoidle_count == 0)
+                       c->ops->allow_idle(c);
+               spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
+       }
        return 0;
 }
 
@@ -201,8 +223,7 @@ int omap2_clk_enable_autoidle_all(void)
        struct clk_hw_omap *c;
 
        list_for_each_entry(c, &clk_hw_omap_clocks, node)
-               if (c->ops && c->ops->allow_idle)
-                       c->ops->allow_idle(c);
+               omap2_clk_allow_idle(c->hw.clk);
 
        _clk_generic_allow_autoidle_all();
 
@@ -223,8 +244,7 @@ int omap2_clk_disable_autoidle_all(void)
        struct clk_hw_omap *c;
 
        list_for_each_entry(c, &clk_hw_omap_clocks, node)
-               if (c->ops && c->ops->deny_idle)
-                       c->ops->deny_idle(c);
+               omap2_clk_deny_idle(c->hw.clk);
 
        _clk_generic_deny_autoidle_all();
 
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index eacc5df57b99..78872efc7be0 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -160,6 +160,7 @@ struct clk_hw_omap {
        struct clockdomain      *clkdm;
        const struct clk_hw_omap_ops    *ops;
        u32                     context;
+       int                     autoidle_count;
 };
 
 /*
-- 
2.11.0