linux-kernel - [PATCH v42 1/6] clk: Allow clocks to be marked as CRITICAL

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Message-Id: <1455225554-13267-2-git-send-email-mturquette@baylibre.com>
Date:	Thu, 11 Feb 2016 13:19:09 -0800
From:	Michael Turquette <mturquette@...libre.com>
To:	linux-clk@...r.kernel.org
Cc:	lee.jones@...aro.org, sboyd@...eaurora.org,
	maxime.ripard@...e-electrons.com, maxime.coquelin@...com,
	geert@...ux-m68k.org, heiko@...ech.de, andre.przywara@....com,
	rklein@...dia.com, linux-kernel@...r.kernel.org,
	Michael Turquette <mturquette@...libre.com>
Subject: [PATCH v42 1/6] clk: Allow clocks to be marked as CRITICAL

From: Lee Jones <lee.jones@...aro.org>

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@...aro.org>
Signed-off-by: Michael Turquette <mturquette@...libre.com>
---
Changes in v42:
  * Moved code from clk_register into __clk_init

 drivers/clk/clk.c            | 5 +++++
 include/linux/clk-provider.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b4db67a..993f775 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2484,6 +2484,11 @@ static int __clk_init(struct device *dev, struct clk *clk_user)
 	if (core->ops->init)
 		core->ops->init(core->hw);
 
+	if (core->flags & CLK_IS_CRITICAL) {
+		clk_core_prepare(core);
+		clk_core_enable(core);
+	}
+
 	kref_init(&core->ref);
 out:
 	clk_prepare_unlock();
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 1143e38..1d986ea 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -32,6 +32,7 @@
 #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_SET_RATE_UNGATE	BIT(10) /* clock needs to run to set rate */
+#define CLK_IS_CRITICAL		BIT(11) /* do not gate, ever */
 
 struct clk;
 struct clk_hw;
-- 
2.1.4