From: emilio@elopez•com.ar (Emilio López)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] clk: respect the clock dependencies in of_clk_init
Date: Fri, 07 Feb 2014 13:16:36 -0300 [thread overview]
Message-ID: <52F506E4.8070900@elopez.com.ar> (raw)
In-Reply-To: <52F4F7EF.7090900@free-electrons.com>
Hi Gregory,
El 07/02/14 12:12, Gregory CLEMENT escribi?:
> On 07/02/2014 16:00, Emilio L?pez wrote:
>> El 07/02/14 11:49, Gregory CLEMENT escribi?:
>>> On 07/02/2014 15:43, Ezequiel Garcia wrote:
>>>> On Fri, Feb 07, 2014 at 09:24:30AM -0500, Jason Cooper wrote:
>>>>> On Fri, Feb 07, 2014 at 10:06:08AM -0300, Emilio L?pez wrote:
>>>>>
>>>>> [snip a great explanation]
>>>>>
>>>>> Guys, can I get some Tested-by's on this?
>>>>>
>>>>
>>>> In case someone missed Emilio's comment about it, I gave his oneliner
>>>> a test on A370 Reference Design. It worked just as well as Sebastian's.
>>>
>>> Well ok it's working but this patch is not better than Sebastian, it is
>>> even worth. I don't think it is a good idea at all to totally ignore the
>>> information given by the device tree.
>>
>> With a bit more work, you can replace the clk_get magic with a call to
>> of_clk_get_parent_name() or similar to be able to keep overriding stuff
>> from DT. This way it would completely match the behaviour on
>> mvebu_coreclk_setup (default to "tclk", allow overriding with DT).
>>
>
> I think you didn't have a look on our implementation:
I did, several times in fact.
> the name of the clock
> are created by the driver during the initialization.
The name of the clock is always "tclk", as hardcoded on the driver,
unless overridden via clock-output-names from DT (see
mvebu_coreclk_setup). Currently none of your DT that I can see does
this, so in practice it's always "tclk".
> That's why we need that
> the parent clock are initialized before the gating clock.
You don't really *need* that. The driver just does that because it may
have been convenient at the time and it worked. Defaulting to "tclk" on
mvebu_clk_gating_setup and overriding it if it turns out it has some
other name on the DT (just like on mvebu_coreclk_setup!) should work as
well, and doesn't require complex, bloaty, dependency management.
Rough, untested patch below, so you get the idea.
Cheers,
Emilio
---
drivers/clk/mvebu/common.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/clk/mvebu/common.c b/drivers/clk/mvebu/common.c
index 25ceccf..730625b 100644
--- a/drivers/clk/mvebu/common.c
+++ b/drivers/clk/mvebu/common.c
@@ -119,19 +119,20 @@ void __init mvebu_clk_gating_setup(struct
device_node *np,
const struct clk_gating_soc_desc *desc)
{
struct clk_gating_ctrl *ctrl;
- struct clk *clk;
void __iomem *base;
- const char *default_parent = NULL;
+ struct of_phandle_args clkspec;
+ const char *default_parent = "tclk";
int n;
base = of_iomap(np, 0);
if (WARN_ON(!base))
return;
- clk = of_clk_get(np, 0);
- if (!IS_ERR(clk)) {
- default_parent = __clk_get_name(clk);
- clk_put(clk);
+ if (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", 0,
&clkspec)) {
+ of_property_read_string_index(clkspec.np, "clock-output-names",
+ clkspec.args_count ? clkspec.args[0] : 0,
+ &default_parent);
+ of_node_put(clkspec.np);
}
ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
--
1.8.5.3
next prev parent reply other threads:[~2014-02-07 16:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-04 22:59 [PATCH] clk: respect the clock dependencies in of_clk_init Gregory CLEMENT
2014-02-05 5:09 ` Jason Cooper
2014-02-05 8:45 ` Boris BREZILLON
2014-02-05 9:48 ` [PATCH] clk: add strict of_clk_init dependency check Boris BREZILLON
2014-02-05 14:48 ` Gregory CLEMENT
2014-02-05 15:05 ` Gregory CLEMENT
2014-02-05 15:07 ` Boris BREZILLON
2014-02-05 23:11 ` [PATCH] clk: respect the clock dependencies in of_clk_init Sebastian Hesselbarth
2014-02-07 13:06 ` Emilio López
2014-02-07 14:24 ` Jason Cooper
2014-02-07 14:43 ` Ezequiel Garcia
2014-02-07 14:49 ` Gregory CLEMENT
2014-02-07 15:00 ` Emilio López
2014-02-07 15:12 ` Gregory CLEMENT
2014-02-07 16:16 ` Emilio López [this message]
2014-02-07 18:10 ` Gregory CLEMENT
2014-02-07 18:17 ` Emilio López
2014-02-07 23:15 ` Sebastian Hesselbarth
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