Subject: [RESEND PATCH 1/3] clk: Remove _clk_reparent from API and restructure code

From: [email-masked] (Mike Turquette)
Date: Tue, 19 Mar 2013 14:20:53 -0700

Quoting Ulf Hansson (2013-03-12 12:20:48)
> From: Ulf Hansson <[email-masked]>
> 
> There shall be no reason for keeping this API available for clock
> providers. So we remove it from the API and restrcuture the code so
> for example the COMMON_CLK_DEBUG part is separated.
> 

Hi Ulf,

There is one reason to keep this api.  OMAP currently uses it to change
the parent of a PLL during .set_rate.  This is kind of a legacy
mechanism however, and the reentrancy series I posted actually takes
care of this one corner case:
http://article.gmane.org/gmane.linux.kernel/1448449

Let me see how the OMAP folks feel about taking that patch in, which
eliminates the only external user of the API.  +Rajendra & Benoit

Thanks,
Mike

> This patch will also make it possible to hold the spinlock over the
> actual update of the clock tree topology, which could not be done
> before when both debugfs updates and clock rate updates was done
> within the same function.
> 
> Signed-off-by: Ulf Hansson <[email-masked]>
> ---
>  drivers/clk/clk.c            |   82 ++++++++++++++++++++++++------------------
>  include/linux/clk-provider.h |    1 -
>  2 files changed, 48 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 593a2e4..2e10cc1 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -284,6 +284,39 @@ out:
>  }
>  
>  /**
> + * clk_debug_reparent - reparent clk node in the debugfs clk tree
> + * @clk: the clk being reparented
> + * @new_parent: the new clk parent, may be NULL
> + *
> + * Rename clk entry in the debugfs clk tree if debugfs has been
> + * initialized.  Otherwise it bails out early since the debugfs clk tree
> + * will be created lazily by clk_debug_init as part of a late_initcall.
> + *
> + * Caller must hold prepare_lock.
> + */
> +static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
> +{
> +       struct dentry *d;
> +       struct dentry *new_parent_d;
> +
> +       if (!inited)
> +               return;
> +
> +       if (new_parent)
> +               new_parent_d = new_parent->dentry;
> +       else
> +               new_parent_d = orphandir;
> +
> +       d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
> +                       new_parent_d, clk->name);
> +       if (d)
> +               clk->dentry = d;
> +       else
> +               pr_debug("%s: failed to rename debugfs entry for %s\n",
> +                               __func__, clk->name);
> +}
> +
> +/**
>   * clk_debug_init - lazily create the debugfs clk tree visualization
>   *
>   * clks are often initialized very early during boot before memory can
> @@ -338,6 +371,9 @@ static int __init clk_debug_init(void)
>  late_initcall(clk_debug_init);
>  #else
>  static inline int clk_debug_register(struct clk *clk) { return 0; }
> +static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
> +{
> +}
>  #endif
>  
>  /* caller must hold prepare_lock */
> @@ -1179,16 +1215,8 @@ out:
>         return ret;
>  }
>  
> -void __clk_reparent(struct clk *clk, struct clk *new_parent)
> +static void clk_reparent(struct clk *clk, struct clk *new_parent)
>  {
> -#ifdef CONFIG_COMMON_CLK_DEBUG
> -       struct dentry *d;
> -       struct dentry *new_parent_d;
> -#endif
> -
> -       if (!clk || !new_parent)
> -               return;
> -
>         hlist_del(&clk->child_node);
>  
>         if (new_parent)
> @@ -1196,28 +1224,7 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent)
>         else
>                 hlist_add_head(&clk->child_node, &clk_orphan_list);
>  
> -#ifdef CONFIG_COMMON_CLK_DEBUG
> -       if (!inited)
> -               goto out;
> -
> -       if (new_parent)
> -               new_parent_d = new_parent->dentry;
> -       else
> -               new_parent_d = orphandir;
> -
> -       d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
> -                       new_parent_d, clk->name);
> -       if (d)
> -               clk->dentry = d;
> -       else
> -               pr_debug("%s: failed to rename debugfs entry for %s\n",
> -                               __func__, clk->name);
> -out:
> -#endif
> -
>         clk->parent = new_parent;
> -
> -       __clk_recalc_rates(clk, POST_RATE_CHANGE);
>  }
>  
>  static int __clk_set_parent(struct clk *clk, struct clk *parent)
> @@ -1329,7 +1336,9 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
>         }
>  
>         /* propagate rate recalculation downstream */
> -       __clk_reparent(clk, parent);
> +       clk_reparent(clk, parent);
> +       clk_debug_reparent(clk, parent);
> +       __clk_recalc_rates(clk, POST_RATE_CHANGE);
>  
>  out:
>         mutex_unlock(&prepare_lock);
> @@ -1453,14 +1462,19 @@ int __clk_init(struct device *dev, struct clk *clk)
>         hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) {
>                 if (orphan->ops->get_parent) {
>                         i = orphan->ops->get_parent(orphan->hw);
> -                       if (!strcmp(clk->name, orphan->parent_names[i]))
> -                               __clk_reparent(orphan, clk);
> +                       if (!strcmp(clk->name, orphan->parent_names[i])) {
> +                               clk_reparent(orphan, clk);
> +                               clk_debug_reparent(orphan, clk);
> +                               __clk_recalc_rates(orphan, POST_RATE_CHANGE);
> +                       }
>                         continue;
>                 }
>  
>                 for (i = 0; i < orphan->num_parents; i++)
>                         if (!strcmp(clk->name, orphan->parent_names[i])) {
> -                               __clk_reparent(orphan, clk);
> +                               clk_reparent(orphan, clk);
> +                               clk_debug_reparent(orphan, clk);
> +                               __clk_recalc_rates(orphan, POST_RATE_CHANGE);
>                                 break;
>                         }
>          }
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 4989b8a..87a7c2c 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -359,7 +359,6 @@ struct clk *__clk_lookup(const char *name);
>   */
>  int __clk_prepare(struct clk *clk);
>  void __clk_unprepare(struct clk *clk);
> -void __clk_reparent(struct clk *clk, struct clk *new_parent);
>  unsigned long __clk_round_rate(struct clk *clk, unsigned long rate);
>  
>  struct of_device_id;
> -- 
> 1.7.10