linux-kernel - [PATCH 3/4] clk: add CLK_DEFER_ORPHAN flag to prevent orphans from being used

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Date:	Thu,  2 Apr 2015 17:34:12 +0200
From:	Heiko Stuebner <heiko@...ech.de>
To:	mturquette@...aro.org
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, dianders@...omium.org,
	linux@....linux.org.uk, Heiko Stuebner <heiko@...ech.de>
Subject: [PATCH 3/4] clk: add CLK_DEFER_ORPHAN flag to prevent orphans from being used

The usage of clocks derived from an orphan can produce issues when trying
to set rates etc. So ideally a clk_get to such a clock should defer till
the clock hierarchy is complete.
But as some arches probably rely on such clocks we can't disable them all.
Therefore add a new clk flag where arches can enable this behaviour for
their clocks.

Signed-off-by: Heiko Stuebner <heiko@...ech.de>
---
 drivers/clk/clk.c            | 6 ++++++
 include/linux/clk-provider.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 476f491..8511c62 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3041,6 +3041,12 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 		if (provider->node == clkspec->np)
 			clk = provider->get(clkspec, provider->data);
 		if (!IS_ERR(clk)) {
+			if ((__clk_get_flags(clk) & CLK_DEFER_ORPHAN)
+						&& clk_is_orphan(clk)) {
+				clk = ERR_PTR(-EPROBE_DEFER);
+				break;
+			}
+
 			clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
 					       con_id);
 
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 28abf1b..ef8d669 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -31,6 +31,7 @@
 #define CLK_GET_RATE_NOCACHE	BIT(6) /* do not use the cached clk rate */
 #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_DEFER_ORPHAN	BIT(9) /* defer clk_get calls for orphans */
 
 struct clk_hw;
 struct clk_core;
-- 
2.1.4

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