1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/clk/at91/clk-slow.c b/drivers/clk/at91/clk-slow.c
index 32f7c1b36204..2f13bd5246b5 100644
--- a/drivers/clk/at91/clk-slow.c
+++ b/drivers/clk/at91/clk-slow.c
@@ -70,6 +70,7 @@ struct clk_sam9x5_slow {
 
 #define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)
 
+static struct clk *slow_clk;
 
 static int clk_slow_osc_prepare(struct clk_hw *hw)
 {
@@ -357,6 +358,8 @@ at91_clk_register_sam9x5_slow(void __iomem *sckcr,
         clk = clk_register(NULL, &slowck->hw);
         if (IS_ERR(clk))
                 kfree(slowck);
+        else
+                slow_clk = clk;
 
         return clk;
 }
@@ -433,6 +436,8 @@ at91_clk_register_sam9260_slow(struct at91_pmc *pmc,
         clk = clk_register(NULL, &slowck->hw);
         if (IS_ERR(clk))
                 kfree(slowck);
+        else
+                slow_clk = clk;
 
         return clk;
 }
@@ -465,3 +470,25 @@ void __init of_at91sam9260_clk_slow_setup(struct device_node *np,
 
         of_clk_add_provider(np, of_clk_src_simple_get, clk);
 }
+
+/*
+ * FIXME: All slow clk users are not properly claiming it (get + prepare +
+ * enable) before using it.
+ * If all users properly claiming this clock decide that they don't need it
+ * anymore (or are removed), it is disabled while faulty users are still
+ * requiring it, and the system hangs.
+ * Prevent this clock from being disabled until all users are properly
+ * requesting it.
+ * Once this is done we should remove this function and the slow_clk variable.
+ */
+static int __init of_at91_clk_slow_retain(void)
+{
+        if (!slow_clk)
+                return 0;
+
+        __clk_get(slow_clk);
+        clk_prepare_enable(slow_clk);
+
+        return 0;
+}
+arch_initcall(of_at91_clk_slow_retain);