clk: Allow clocks to be marked as CRITICAL

Critical clocks are those which must not be gated, else undefined
or catastrophic failure would occur.  Here we have chosen to
ensure the prepare/enable counts are correctly incremented, so as
not to confuse users with enabled clocks with no visible users.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/1455225554-13267-2-git-send-email-mturquette@baylibre.com
[cw00.choi: Fix the merge conflict and apply the mainline patch]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Change-Id: Ic4ec2959426dc4a424bf71bdc6b725dd9022616c

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 4fa21d2..9e7ff02 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2439,6 +2439,11 @@ static int __clk_init(struct device *dev, struct clk *clk_user)
        if (clk->ops->init)
                clk->ops->init(clk->hw);
 
+       if (clk->flags & CLK_IS_CRITICAL) {
+               clk_core_prepare(clk);
+               clk_core_enable(clk);
+       }
+
        kref_init(&clk->ref);
 out:
        clk_prepare_unlock();

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 82f59ca..ff24441 100644 (file)
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -32,6 +32,7 @@
 #define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */
 #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
 #define CLK_RECALC_NEW_RATES   BIT(9) /* recalc rates after notifications */
+#define CLK_IS_CRITICAL                BIT(11) /* do not gate, ever */
 
 struct clk_hw;
 struct clk_core;