Subject: Re: [PATCH v3 4/5] clk: Add consumer APIs for discovering possible parent clocks

From: Scott Wood <[email-masked]>
Date: Thu, 15 Oct 2015 15:03:32 -0500

On Sat, 2015-09-19 at 23:29 -0500, Scott Wood wrote:
> Commit fc4a05d4b0eb ("clk: Remove unused provider APIs") removed
> __clk_get_num_parents() and clk_hw_get_parent_by_index(), leaving only
> true provider API versions that operate on struct clk_hw.
> 
> qoriq-cpufreq needs these functions in order to determine the options
> it has for calling clk_set_parent() and thus populate the cpufreq
> table, so revive them as legitimate consumer APIs.
> 
> Signed-off-by: Scott Wood <[email-masked]>
> ---
> v3: new patch
> 
>  drivers/clk/clk.c   | 19 +++++++++++++++++++
>  include/linux/clk.h | 31 +++++++++++++++++++++++++++++++
>  2 files changed, 50 insertions(+)

Russell, could you ACK this if there are no objections?

Thanks,
Scott

> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 43e2c3a..9436356 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -290,6 +290,12 @@ struct clk_hw *__clk_get_hw(struct clk *clk)
>  }
>  EXPORT_SYMBOL_GPL(__clk_get_hw);
>  
> +unsigned int clk_get_num_parents(struct clk *clk)
> +{
> +     return !clk ? 0 : clk->core->num_parents;
> +}
> +EXPORT_SYMBOL_GPL(clk_get_num_parents);
> +
>  unsigned int clk_hw_get_num_parents(const struct clk_hw *hw)
>  {
>       return hw->core->num_parents;
> @@ -359,6 +365,19 @@ static struct clk_core 
> *clk_core_get_parent_by_index(struct clk_core *core,
>               return core->parents[index];
>  }
>  
> +struct clk *clk_get_parent_by_index(struct clk *clk, unsigned int index)
> +{
> +     struct clk_core *parent;
> +
> +     if (!clk)
> +             return NULL;
> +
> +     parent = clk_core_get_parent_by_index(clk->core, index);
> +
> +     return !parent ? NULL : parent->hw->clk;
> +}
> +EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
> +
>  struct clk_hw *
>  clk_hw_get_parent_by_index(const struct clk_hw *hw, unsigned int index)
>  {
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 0df4a51..937de0e 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -392,6 +392,26 @@ int clk_set_parent(struct clk *clk, struct clk 
> *parent);
>  struct clk *clk_get_parent(struct clk *clk);
>  
>  /**
> + * clk_get_parent_by_index - get a possible parent clock by index
> + * @clk: clock source
> + * @index: index into the array of possible parents of this clock
> + *
> + * Returns struct clk corresponding to the requested possible
> + * parent clock source, or NULL.
> + */
> +struct clk *clk_get_parent_by_index(struct clk *clk,
> +                                 unsigned int index);
> +
> +/**
> + * clk_get_num_parents - get number of possible parents
> + * @clk: clock source
> + *
> + * Returns the number of possible parents of this clock,
> + * which can then be enumerated using clk_get_parent_by_index().
> + */
> +unsigned int clk_get_num_parents(struct clk *clk);
> +
> +/**
>   * clk_get_sys - get a clock based upon the device name
>   * @dev_id: device name
>   * @con_id: connection ID
> @@ -461,6 +481,17 @@ static inline struct clk *clk_get_parent(struct clk 
> *clk)
>       return NULL;
>  }
>  
> +struct clk *clk_get_parent_by_index(struct clk *clk,
> +                                 unsigned int index)
> +{
> +     return NULL;
> +}
> +
> +unsigned int clk_get_num_parents(struct clk *clk)
> +{
> +     return 0;
> +}
> +
>  #endif
>  
>  /* clk_prepare_enable helps cases using clk_enable in non-atomic context. 
> */