[PATCH] clk: Add clk_parent entry in debugfs

[PATCH] clk: Add clk_parent entry in debugfs

[Leonard Crestez]

This allows to easily determine the parent in shell scripts without
parsing more complex files.

Add the clk_parent file unconditionally because this information is
useful for more than just muxes.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
---
 drivers/clk/clk.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index aa51756fd4d6..94a93b07dd37 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3009,10 +3009,21 @@ static int possible_parents_show(struct seq_file *s, void *data)
 
 	return 0;
 }
 DEFINE_SHOW_ATTRIBUTE(possible_parents);
 
+static int current_parent_show(struct seq_file *s, void *data)
+{
+	struct clk_core *core = s->private;
+
+	if (core->parent)
+		seq_printf(s, "%s\n", core->parent->name);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(current_parent);
+
 static int clk_duty_cycle_show(struct seq_file *s, void *data)
 {
 	struct clk_core *core = s->private;
 	struct clk_duty *duty = &core->duty;
 
@@ -3040,10 +3051,11 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 	debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);
 	debugfs_create_u32("clk_protect_count", 0444, root, &core->protect_count);
 	debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count);
 	debugfs_create_file("clk_duty_cycle", 0444, root, core,
 			    &clk_duty_cycle_fops);
+	debugfs_create_file("clk_parent", 0444, root, core, &current_parent_fops);
 
 	if (core->num_parents > 1)
 		debugfs_create_file("clk_possible_parents", 0444, root, core,
 				    &possible_parents_fops);
 
-- 
2.17.1


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Re: [PATCH] clk: Add clk_parent entry in debugfs

[Stephen Boyd]

Quoting Leonard Crestez (2019-05-24 01:25:25)
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index aa51756fd4d6..94a93b07dd37 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -3009,10 +3009,21 @@ static int possible_parents_show(struct seq_file *s, void *data)
>  
>         return 0;
>  }
>  DEFINE_SHOW_ATTRIBUTE(possible_parents);
>  
> +static int current_parent_show(struct seq_file *s, void *data)
> +{
> +       struct clk_core *core = s->private;
> +
> +       if (core->parent)
> +               seq_printf(s, "%s\n", core->parent->name);
> +
> +       return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(current_parent);

Looks OK.

> +
>  static int clk_duty_cycle_show(struct seq_file *s, void *data)
>  {
>         struct clk_core *core = s->private;
>         struct clk_duty *duty = &core->duty;
>  
> @@ -3040,10 +3051,11 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
>         debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);
>         debugfs_create_u32("clk_protect_count", 0444, root, &core->protect_count);
>         debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count);
>         debugfs_create_file("clk_duty_cycle", 0444, root, core,
>                             &clk_duty_cycle_fops);
> +       debugfs_create_file("clk_parent", 0444, root, core, &current_parent_fops);

Shouldn't we skip creation of this file if core->num_parents == 0? So
put this under the if condition below?

>  
>         if (core->num_parents > 1)
>                 debugfs_create_file("clk_possible_parents", 0444, root, core,
>                                     &possible_parents_fops);
>  

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Re: [PATCH] clk: Add clk_parent entry in debugfs

[Leonard Crestez]

On 6/7/19 10:05 PM, Stephen Boyd wrote:
> Quoting Leonard Crestez (2019-05-24 01:25:25)

>> @@ -3040,10 +3051,11 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
>>          debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);
>>          debugfs_create_u32("clk_protect_count", 0444, root, &core->protect_count);
>>          debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count);
>>          debugfs_create_file("clk_duty_cycle", 0444, root, core,
>>                              &clk_duty_cycle_fops);
>> +       debugfs_create_file("clk_parent", 0444, root, core, &current_parent_fops);
> 
> Shouldn't we skip creation of this file if core->num_parents == 0? So
> put this under the if condition below?

It's still useful to determine clk tree structure from debugfs fields, 
otherwise you'd have to extract by parsing other files.

Would you hide clk_rate for fixed-rate? I'd rather have everything 
available for uniformity, even if it's otherwise constant at runtime.

--
Regards,
Leonard

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Re: [PATCH] clk: Add clk_parent entry in debugfs

[Geert Uytterhoeven]

Hi Leonard,

On Sat, Jun 8, 2019 at 9:26 AM Leonard Crestez <leonard.crestez@nxp.com> wrote:
> On 6/7/19 10:05 PM, Stephen Boyd wrote:
> > Quoting Leonard Crestez (2019-05-24 01:25:25)
>
> >> @@ -3040,10 +3051,11 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
> >>          debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);
> >>          debugfs_create_u32("clk_protect_count", 0444, root, &core->protect_count);
> >>          debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count);
> >>          debugfs_create_file("clk_duty_cycle", 0444, root, core,
> >>                              &clk_duty_cycle_fops);
> >> +       debugfs_create_file("clk_parent", 0444, root, core, &current_parent_fops);
> >
> > Shouldn't we skip creation of this file if core->num_parents == 0? So
> > put this under the if condition below?
>
> It's still useful to determine clk tree structure from debugfs fields,
> otherwise you'd have to extract by parsing other files.
>
> Would you hide clk_rate for fixed-rate? I'd rather have everything
> available for uniformity, even if it's otherwise constant at runtime.

Unless I' missing something, there's a big difference here: all clocks
have a rate, but not all clocks have a parent.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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Re: [PATCH] clk: Add clk_parent entry in debugfs

[Leonard Crestez]

On 6/8/19 3:19 PM, Geert Uytterhoeven wrote:
> Hi Leonard,
> 
> On Sat, Jun 8, 2019 at 9:26 AM Leonard Crestez <leonard.crestez@nxp.com> wrote:
>> On 6/7/19 10:05 PM, Stephen Boyd wrote:
>>> Quoting Leonard Crestez (2019-05-24 01:25:25)
>>
>>>> @@ -3040,10 +3051,11 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
>>>>           debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);
>>>>           debugfs_create_u32("clk_protect_count", 0444, root, &core->protect_count);
>>>>           debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count);
>>>>           debugfs_create_file("clk_duty_cycle", 0444, root, core,
>>>>                               &clk_duty_cycle_fops);
>>>> +       debugfs_create_file("clk_parent", 0444, root, core, &current_parent_fops);
>>>
>>> Shouldn't we skip creation of this file if core->num_parents == 0? So
>>> put this under the if condition below?
>>
>> It's still useful to determine clk tree structure from debugfs fields,
>> otherwise you'd have to extract by parsing other files.
>>
>> Would you hide clk_rate for fixed-rate? I'd rather have everything
>> available for uniformity, even if it's otherwise constant at runtime.
> 
> Unless I' missing something, there's a big difference here: all clocks
> have a rate, but not all clocks have a parent.

Sorry, I got confused and thought that condition checked for muxes so 
the parent of intermediate clk nodes will be hidden. But intermediate 
nodes have num_parents == 1.

Will fix in v2.

--
Regards,
Leonard

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