[PATCH V2] clk: Add composite clock type

Prashant Gaikwad
2013-02-06T09:52:54Z

On Wednesday 06 February 2013 11:40 AM, Hiroshi Doyu wrote:
> Prashant Gaikwad <pgaikwad@nvidia.com> wrote @ Wed, 6 Feb 2013 03:55:00 +0100:
>
>>>> No, clk_ops depends on the clocks you are using. There could be a clock
>>>> with mux and gate while another one with mux and div.
>>> You are right. What about the following? We don't have to have similar
>>> copy of clk_composite_ops for each instances.
>> Clock framework takes decision depending on the ops availability and it
>> does not know if the clock is mux or gate.
>>
>> For example,
>>
>> if (clk->ops->enable) {
>> ret = clk->ops->enable(clk->hw);
>> if (ret) {
>> __clk_disable(clk->parent);
>> return ret;
>> }
>> }
>>
>> in above case if clk_composite does not have gate clock then as per your
>> suggestion if it returns error value then it will fail and it is wrong.
> Ok, now I understand. Thank you for explanation.
>
> We always need to allocate clk_composite_ops for each clk_composite,
> right? If so what about having "struct clk_ops ops" in "struct
> clk_composite"?
>
> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
> index f30fb4b..5240e24 100644
> --- a/drivers/clk/clk-composite.c
> +++ b/drivers/clk/clk-composite.c
> @@ -129,20 +129,13 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
> pr_err("%s: could not allocate composite clk\n", __func__);
> return ERR_PTR(-ENOMEM);
> }
> + clk_composite_ops = &composite->ops;
>
> init.name = name;
> init.flags = flags | CLK_IS_BASIC;
> init.parent_names = parent_names;
> init.num_parents = num_parents;
>
> - /* allocate the clock ops */
> - clk_composite_ops = kzalloc(sizeof(*clk_composite_ops), GFP_KERNEL);
> - if (!clk_composite_ops) {
> - pr_err("%s: could not allocate clk ops\n", __func__);
> - kfree(composite);
> - return ERR_PTR(-ENOMEM);
> - }
> -
> if (mux_hw && mux_ops) {
> if (!mux_ops->get_parent || !mux_ops->set_parent) {
> clk = ERR_PTR(-EINVAL);
> @@ -202,7 +195,6 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
> return clk;
>
> err:
> - kfree(clk_composite_ops);
> kfree(composite);
> return clk;
> }
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index f0ac818..bb5d36a 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -346,6 +346,8 @@ struct clk_composite {
> const struct clk_ops *mux_ops;
> const struct clk_ops *div_ops;
> const struct clk_ops *gate_ops;
> +
> + const struct clk_ops ops;
> };
>
> struct clk *clk_register_composite(struct device *dev, const char *name,

This will work, but there is no harm in allocating dynamically. What is
preferred?

>
>>> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
>>> index f30fb4b..8f88805 100644
>>> --- a/drivers/clk/clk-composite.c
>>> +++ b/drivers/clk/clk-composite.c
>>> @@ -27,6 +27,9 @@ static u8 clk_composite_get_parent(struct clk_hw *hw)
>>> const struct clk_ops *mux_ops = composite->mux_ops;
>>> struct clk_hw *mux_hw = composite->mux_hw;
>>>
>>> + if (!mux_hw->clk)
>>> + return -EINVAL;
>>> +
>>> mux_hw->clk = hw->clk;
>> It is wrong.
> Will the above "mux_hw->clk = hw->clk" be removed from the original?