Re: [PATCH] clk: Constify struct clk_init_data

From: Saravana Kannan
Date: Mon May 14 2012 - 21:08:07 EST

On 05/14/2012 02:53 PM, Turquette, Mike wrote:
On Mon, May 14, 2012 at 7:12 AM, Mark Brown<broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Allow drivers to declare their clk_init_data const, the framework really
shouldn't be modifying the data.

Signed-off-by: Mark Brown<broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>

+interested parties

Mark, I like this change but it's reminded me of a few things I meant to
bring up on the list in the past. Certainly some folks will mark their
struct clk_hw_init data as __initconst. Currently none of the
documentation mentions that fact and I'm a bit worried about clk code
which assumes that hw->init will always be around and freely accesses

I think that, as a rule, hw->init cannot be assumed to be valid after
clk_register returns. Would anyone else like to weigh in on it? If so
then I'll cook up a follow-up patch to reflect this in the kerneldoc.

If you mean hw->init pointer can't be assumed to be point to anything valid after clk_register or __clk_register, then yes, I agree with that. But the actual data that hw->init pointed to might still be around and referenced by clk if __clk_register is used.

Btw, I didn't follow up on the other thread we were having, but can you remind me again what was the reason that you thought that only __clk_init() would work for your static init code and __clk_register() won't work? Or did I just misunderstand your comment that was trying to say that you didn't want to switch to __clk_register close to kernel release?

There are some older threads where I think we are a bit out of sync on the init data (I thought I did what you said you preferred, but you asked me why I did that). I will try to restart them.



include/linux/clk-provider.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index c1c23b9..fc43ea6 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -143,7 +143,7 @@ struct clk_init_data {
struct clk_hw {
struct clk *clk;
- struct clk_init_data *init;
+ const struct clk_init_data *init;


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