linux-kernel - [PATCH 1/3] clk: Allow clocks to be marked as CRITICAL

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Message-Id: <1453127331-20616-2-git-send-email-lee.jones@linaro.org>
Date:	Mon, 18 Jan 2016 14:28:49 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	kernel@...inux.com, maxime.coquelin@...com,
	mturquette@...libre.com, sboyd@...eaurora.org,
	maxime.ripard@...e-electrons.com, s.hauer@...gutronix.de,
	geert@...ux-m68k.org, Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 1/3] 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@...aro.org>
---
 drivers/clk/clk.c            | 7 ++++++-
 include/linux/clk-provider.h | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f13c3f4..835cb85 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2576,8 +2576,13 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 	}
 
 	ret = __clk_init(dev, hw->clk);
-	if (!ret)
+	if (!ret) {
+		if (core->flags & CLK_IS_CRITICAL) {
+			clk_core_prepare(core);
+			clk_core_enable(core);
+		}
 		return hw->clk;
+	}
 
 	__clk_free_clk(hw->clk);
 	hw->clk = NULL;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index c56988a..ffa0b2e 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -31,6 +31,7 @@
 #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(10) /* do not gate, ever */
 
 struct clk;
 struct clk_hw;
-- 
1.9.1