[PATCH v3 2/2] clk: prevent orphan clocks from being used

[Heiko Stuebner]

Orphan clocks or children of orphan clocks don't have rate information at
all and can produce strange results if they're allowed to be used and the
parent becomes available later on.

So using the newly introduced orphan status bit defer
__of_clk_get_from_provider calls for orphan clocks.

Signed-off-by: Heiko Stuebner <heiko at sntech.de>
Cc: Boris Brezillon <boris.brezillon at free-electrons.com>
Cc: Alex Elder <elder at linaro.org>
Cc: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Cc: Stephen Warren <swarren at wwwdotorg.org>
Cc: Max Filippov <jcmvbkbc at gmail.com>
Cc: kernel at pengutronix.de
Cc: Zhangfei Gao <zhangfei.gao at linaro.org>
Cc: Santosh Shilimkar <ssantosh at kernel.org>
Cc: Chao Xie <chao.xie at marvell.com>
Cc: Jason Cooper <jason at lakedaemon.net>
Cc: Stefan Wahren <stefan.wahren at i2se.com>
Cc: Andrew Bresticker <abrestic at chromium.org>
Cc: Robert Jarzmik <robert.jarzmik at free.fr>
Cc: Georgi Djakov <georgi.djakov at linaro.org>
Cc: Sylwester Nawrocki <s.nawrocki at samsung.com>
Cc: Geert Uytterhoeven <geert+renesas at glider.be>
Cc: Barry Song <baohua at kernel.org>
Cc: Dinh Nguyen <dinguyen at opensource.altera.com>
Cc: Viresh Kumar <viresh.linux at gmail.com>
Cc: Gabriel FERNANDEZ <gabriel.fernandez at st.com>
Cc: emilio at elopez.com.ar
Cc: Peter De Schrijver <pdeschrijver at nvidia.com>
Cc: Tero Kristo <t-kristo at ti.com>
Cc: Ulf Hansson <ulf.hansson at linaro.org>
Cc: Pawel Moll <pawel.moll at arm.com>
Cc: Michal Simek <michal.simek at xilinx.com>
---
 drivers/clk/clk.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 341904f..27d2d4b 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2226,6 +2226,14 @@ bool clk_is_match(const struct clk *p, const struct clk *q)
 }
 EXPORT_SYMBOL_GPL(clk_is_match);
 
+static bool clk_is_orphan(const struct clk *clk)
+{
+	if (!clk)
+		return false;
+
+	return clk->core->orphan;
+}
+
 /**
  * __clk_init - initialize the data structures in a struct clk
  * @dev:	device initializing this clk, placeholder for now
@@ -2968,6 +2976,11 @@ 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_is_orphan(clk)) {
+				clk = ERR_PTR(-EPROBE_DEFER);
+				break;
+			}
+
 			clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
 					       con_id);
 
-- 
2.1.4