[PATCH v2] clk: Do not complain about correctly set read-only muxes when assigning clock parents from device tree

From: Philipp Zabel
Date: Tue Jan 06 2015 - 10:45:33 EST


Assigning a clock parent to a mux with the CLK_MUX_READ_ONLY flag causes an
error "clk: failed to reparent read_only_mux to already_set_parent: -38"
even if the hardware is already set to the correct parent clock.

This patch avoids the error message by checking whether the correct parent
is already set before calling clk_set_parent. This allows to use the
assigned-clock-parents device tree binding for clock muxes that are not
allowed to be changed anymore at the time of_clk_set_defaults is called.

Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
---
Changes since v1:
- Added Shawn's ack.
- Moved the (rc < 0) check into the body of the if statement, directly after
the rc = clk_set_parent(...) call.
---
drivers/clk/clk-conf.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
index aad4796..bb4dc02 100644
--- a/drivers/clk/clk-conf.c
+++ b/drivers/clk/clk-conf.c
@@ -62,10 +62,13 @@ static int __set_clk_parents(struct device_node *node, bool clk_supplier)
goto err;
}

- rc = clk_set_parent(clk, pclk);
- if (rc < 0)
- pr_err("clk: failed to reparent %s to %s: %d\n",
- __clk_get_name(clk), __clk_get_name(pclk), rc);
+ if (pclk != __clk_get_parent(clk)) {
+ rc = clk_set_parent(clk, pclk);
+ if (rc < 0)
+ pr_err("clk: failed to reparent %s to %s: %d\n",
+ __clk_get_name(clk),
+ __clk_get_name(pclk), rc);
+ }
clk_put(clk);
clk_put(pclk);
}
--
2.1.4

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