[PATCH v3] clk: define and export clk_debugs_add_file

[PATCH v3] clk: define and export clk_debugs_add_file

[Peter De Schrijver]

Define and export a new function clk_debugs_add_file which adds a file
to a existing clock's debugfs directory. This can be used by clock
providers to add debugfs entries which are not related to a specific clock
type. Examples include the ability to measure the rate of a clock. It can
also be used by modules to create new debugfs entries. This is useful if you
want to expose features for testing which can potentially cause system
instability such as allowing to change a clock's rate from userspace.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>

---
Changes in v3:
 * export a function to create a new file in a clock's debugfs directory
   instead of exposing the clock's debugfs dentry pointer

Changes in v2:
 * fix function name in description
 * export function in header file
---
 drivers/clk/clk.c            |   12 ++++++++++++
 include/linux/clk-provider.h |    5 +++++
 2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8b73ede..c1e2fab 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -403,6 +403,18 @@ static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
 				__func__, clk->name);
 }
 
+struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
+				void *data, const struct file_operations *fops)
+{
+	struct dentry *d = NULL;
+
+	if (clk->dentry)
+		d = debugfs_create_file(name, mode, clk->dentry, data, fops);
+
+	return d;
+}
+EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
+
 /**
  * clk_debug_init - lazily create the debugfs clk tree visualization
  *
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 0c287db..411dd7e 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -619,5 +619,10 @@ static inline void clk_writel(u32 val, u32 __iomem *reg)
 
 #endif	/* platform dependent I/O accessors */
 
+#ifdef CONFIG_DEBUG_FS
+struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
+				void *data, const struct file_operations *fops);
+#endif
+
 #endif /* CONFIG_COMMON_CLK */
 #endif /* CLK_PROVIDER_H */
-- 
1.7.7.rc0.72.g4b5ea.dirty

[PATCH v3] clk: define and export clk_debugs_add_file

[Mike Turquette]

Quoting Peter De Schrijver (2014-06-26 08:00:53)
> Define and export a new function clk_debugs_add_file which adds a file
> to a existing clock's debugfs directory. This can be used by clock
> providers to add debugfs entries which are not related to a specific clock
> type. Examples include the ability to measure the rate of a clock. It can
> also be used by modules to create new debugfs entries. This is useful if you
> want to expose features for testing which can potentially cause system
> instability such as allowing to change a clock's rate from userspace.
> 
> Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>

Applied to clk-next. If you have some useful examples of how you use
this in downstream kernels or in out-of-tree modules then it would be
great to post them to the list. Others might find them helpful.

Regards,
Mike

> 
> ---
> Changes in v3:
>  * export a function to create a new file in a clock's debugfs directory
>    instead of exposing the clock's debugfs dentry pointer
> 
> Changes in v2:
>  * fix function name in description
>  * export function in header file
> ---
>  drivers/clk/clk.c            |   12 ++++++++++++
>  include/linux/clk-provider.h |    5 +++++
>  2 files changed, 17 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 8b73ede..c1e2fab 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -403,6 +403,18 @@ static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
>                                 __func__, clk->name);
>  }
>  
> +struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
> +                               void *data, const struct file_operations *fops)
> +{
> +       struct dentry *d = NULL;
> +
> +       if (clk->dentry)
> +               d = debugfs_create_file(name, mode, clk->dentry, data, fops);
> +
> +       return d;
> +}
> +EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
> +
>  /**
>   * clk_debug_init - lazily create the debugfs clk tree visualization
>   *
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 0c287db..411dd7e 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -619,5 +619,10 @@ static inline void clk_writel(u32 val, u32 __iomem *reg)
>  
>  #endif /* platform dependent I/O accessors */
>  
> +#ifdef CONFIG_DEBUG_FS
> +struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
> +                               void *data, const struct file_operations *fops);
> +#endif
> +
>  #endif /* CONFIG_COMMON_CLK */
>  #endif /* CLK_PROVIDER_H */
> -- 
> 1.7.7.rc0.72.g4b5ea.dirty
>