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SubjectRe: [PATCH] clk: add strict of_clk_init dependency check
On 05/02/2014 15:48, Gregory CLEMENT wrote:
> Hi Boris,
>
> On 05/02/2014 10:48, Boris BREZILLON wrote:
>> The parent dependency check is only available on the first parent of a given
>> clk.
>>
>> Add support for strict dependency check: all parents of a given clk must be
>> initialized.
>>
>> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
>> ---
>>
>> Hello Gregory,
>>
>> This patch adds support for strict check on clk dependencies (check if all
>> parents specified by an DT clk node are initialized).
>>
>> I'm not sure this is what you were expecting (maybe testing the first parent
>> is what you really want), so please feel free to tell me if I'm wrong.
>>
>> Best Regards,
>>
>> Boris
>>
>> drivers/clk/clk.c | 27 +++++++++++++++++++++------
>> 1 file changed, 21 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
>> index beb0f8b..6849769 100644
>> --- a/drivers/clk/clk.c
>> +++ b/drivers/clk/clk.c
>> @@ -2543,22 +2543,37 @@ static int parent_ready(struct device_node *np)
>> {
>> struct of_phandle_args clkspec;
>> struct of_clk_provider *provider;
>> + int num_parents;
>> + bool found;
>> + int i;
>>
>> /*
>> * If there is no clock parent, no need to wait for them, then
>> * we can consider their absence as being ready
>> */
>> - if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", 0,
>> - &clkspec))
>> + num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
>> + if (num_parents <= 0)
>> return 1;
>>
>> - /* Check if we have such a provider in our array */
>> - list_for_each_entry(provider, &of_clk_providers, link) {
>> - if (provider->node == clkspec.np)
>> + for (i = 0; i < num_parents; i++) {
>> + if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
>> + &clkspec))
>> return 1;
>> +
>> + /* Check if we have such a provider in our array */
>> + found = false;
>> + list_for_each_entry(provider, &of_clk_providers, link) {
>> + if (provider->node == clkspec.np) {
>> + found = true;
>> + break;
>
> Hum this means that as soon as you have one parent then you consider it
> as ready. It is better of what I have done because I only test the 1st
> parent. However I wondered if we should go further by ensuring all the
> parents are ready.

My bad, I read the code too fast. Your code already checks that all the
parents are ready.

So if you agree I will merge your code with mine and send a new patch.

>
> If I am right, there is more than one parent only for the muxer. In this
> case is it really expected that all the parent are ready?
>
> Thanks,
>
> Gregory
>
>> + }
>> + }
>> +
>> + if (!found)
>> + return 0;
>> }
>>
>> - return 0;
>> + return 1;
>> }
>>
>> /**
>>
>
>


--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com


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