On Fri, Jun 17, 2016 at 04:05:33PM -0700, Michael Turquette wrote:

Quoting Maxime Ripard (2016-05-16 05:47:01)

quoted

A fixed factor clock, if it needs to change its rate, by definition do not
have any choice but to modify its parent rate.

Logically it makes sense to always propagate the rate-change request up
to the parent for a fixed-factor clock if we desire to change its rate.
However, I wonder if doing this for all users of fixed-factor-clock in
DT is safe? Some users may be counting on it not changing.

There are 397 instances of fixed-factor-clock in .dts[i] today, so this
change worries me a bit.

Understood.

quoted

Add the CLK_SET_RATE_PARENT flag to that clock so that it can happen

Signed-off-by: Maxime Ripard <redacted>
---
 drivers/clk/clk-fixed-factor.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 75cd6c792cb8..3363abd9b4ae 100644
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c

@@ -167,7 +167,8 @@ void __init of_fixed_factor_clk_setup(struct device_node *node)
        of_property_read_string(node, "clock-output-names", &clk_name);
        parent_name = of_clk_get_parent_name(node, 0);
 
-       clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
+       clk = clk_register_fixed_factor(NULL, clk_name, parent_name,
+                                       CLK_SET_RATE_PARENT,

An alternative would be to pass in the flags you want, somehow. For the
clock you are trying to fix, is it inside of the SoC or external? If it
is internal, and part of a larger clock controller driver, is this for
the legacy style allwinner clock drivers that put everything in DT?

It is :(

What we could do, is have an extra compatible for that clock (like
"allwinner,sun4i-a10-pll3-x2" in that case), and set the flag only for
that compatible.

Would that work for you?

If not, it would better to initialize it statically and shove this
flag into the struct clk_init_data storage.

Hopefully, yes, that should be addressed by the new framework, but I
need reviews to get it merged ;)

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com