Useful for testing mux clocks. One can write the index of the parent to
set into clk_set_parent node, starting from 0. Example
# cat clk_possible_parrents
dout_shared0_div4 dout_shared1_div4
# cat clk_parent
dout_shared0_div4
# echo 1 > clk_set_parent
# cat clk_parent
dout_shared1_div4
Define CLOCK_ALLOW_WRITE_DEBUGFS in drivers/clk/clk.c in order to use
this feature.
Signed-off-by: Sam Protsenko <[email protected]>
---
drivers/clk/clk.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 65508eb89ec9..3e5456580db9 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3214,6 +3214,30 @@ static int current_parent_show(struct seq_file *s, void *data)
}
DEFINE_SHOW_ATTRIBUTE(current_parent);
+#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
+static int clk_set_parent_set(void *data, u64 val)
+{
+ struct clk_core *core = data, *parent;
+ int ret;
+
+ if (val >= core->num_parents)
+ return -EINVAL;
+
+ parent = clk_core_get_parent_by_index(core, val);
+ if (IS_ERR_OR_NULL(parent))
+ return PTR_ERR(parent);
+
+ clk_prepare_lock();
+ ret = clk_core_set_parent_nolock(core, parent);
+ clk_prepare_unlock();
+
+ return ret;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(clk_set_parent_fops, NULL, clk_set_parent_set,
+ "%llu\n");
+#endif
+
static int clk_duty_cycle_show(struct seq_file *s, void *data)
{
struct clk_core *core = s->private;
@@ -3285,9 +3309,14 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
debugfs_create_file("clk_parent", 0444, root, core,
¤t_parent_fops);
- if (core->num_parents > 1)
+ if (core->num_parents > 1) {
debugfs_create_file("clk_possible_parents", 0444, root, core,
&possible_parents_fops);
+#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
+ debugfs_create_file("clk_set_parent", 0200, root, core,
+ &clk_set_parent_fops);
+#endif
+ }
if (core->ops->debug_init)
core->ops->debug_init(core->hw, core->dentry);
--
2.30.2
On Tue, 14 Sept 2021 at 17:19, Sam Protsenko <[email protected]> wrote:
>
> Useful for testing mux clocks. One can write the index of the parent to
> set into clk_set_parent node, starting from 0. Example
>
> # cat clk_possible_parrents
> dout_shared0_div4 dout_shared1_div4
> # cat clk_parent
> dout_shared0_div4
> # echo 1 > clk_set_parent
> # cat clk_parent
> dout_shared1_div4
>
> Define CLOCK_ALLOW_WRITE_DEBUGFS in drivers/clk/clk.c in order to use
> this feature.
>
> Signed-off-by: Sam Protsenko <[email protected]>
> ---
+ Adding more folks for review
Guys, can you please review this one?
> drivers/clk/clk.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 65508eb89ec9..3e5456580db9 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -3214,6 +3214,30 @@ static int current_parent_show(struct seq_file *s, void *data)
> }
> DEFINE_SHOW_ATTRIBUTE(current_parent);
>
> +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> +static int clk_set_parent_set(void *data, u64 val)
> +{
> + struct clk_core *core = data, *parent;
> + int ret;
> +
> + if (val >= core->num_parents)
> + return -EINVAL;
> +
> + parent = clk_core_get_parent_by_index(core, val);
> + if (IS_ERR_OR_NULL(parent))
> + return PTR_ERR(parent);
> +
> + clk_prepare_lock();
> + ret = clk_core_set_parent_nolock(core, parent);
> + clk_prepare_unlock();
> +
> + return ret;
> +}
> +
> +DEFINE_DEBUGFS_ATTRIBUTE(clk_set_parent_fops, NULL, clk_set_parent_set,
> + "%llu\n");
> +#endif
> +
> static int clk_duty_cycle_show(struct seq_file *s, void *data)
> {
> struct clk_core *core = s->private;
> @@ -3285,9 +3309,14 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
> debugfs_create_file("clk_parent", 0444, root, core,
> ¤t_parent_fops);
>
> - if (core->num_parents > 1)
> + if (core->num_parents > 1) {
> debugfs_create_file("clk_possible_parents", 0444, root, core,
> &possible_parents_fops);
> +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> + debugfs_create_file("clk_set_parent", 0200, root, core,
> + &clk_set_parent_fops);
> +#endif
> + }
>
> if (core->ops->debug_init)
> core->ops->debug_init(core->hw, core->dentry);
> --
> 2.30.2
>
Hi Sam,
On Tue, Oct 5, 2021 at 12:11 PM Sam Protsenko
<[email protected]> wrote:
> On Tue, 14 Sept 2021 at 17:19, Sam Protsenko <[email protected]> wrote:
> > Useful for testing mux clocks. One can write the index of the parent to
> > set into clk_set_parent node, starting from 0. Example
> >
> > # cat clk_possible_parrents
> > dout_shared0_div4 dout_shared1_div4
> > # cat clk_parent
> > dout_shared0_div4
> > # echo 1 > clk_set_parent
> > # cat clk_parent
> > dout_shared1_div4
> >
> > Define CLOCK_ALLOW_WRITE_DEBUGFS in drivers/clk/clk.c in order to use
> > this feature.
> >
> > Signed-off-by: Sam Protsenko <[email protected]>
> > ---
>
> + Adding more folks for review
>
> Guys, can you please review this one?
Thanks for your patch!
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -3214,6 +3214,30 @@ static int current_parent_show(struct seq_file *s, void *data)
> > }
> > DEFINE_SHOW_ATTRIBUTE(current_parent);
> >
> > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> > +static int clk_set_parent_set(void *data, u64 val)
u64 is overkill, num_parents is u8.
> > +{
> > + struct clk_core *core = data, *parent;
> > + int ret;
> > +
> > + if (val >= core->num_parents)
> > + return -EINVAL;
clk_core_get_parent_by_index() called below already checks this.
> > +
> > + parent = clk_core_get_parent_by_index(core, val);
> > + if (IS_ERR_OR_NULL(parent))
> > + return PTR_ERR(parent);
> > +
> > + clk_prepare_lock();
> > + ret = clk_core_set_parent_nolock(core, parent);
> > + clk_prepare_unlock();
> > +
> > + return ret;
> > +}
> > +
> > +DEFINE_DEBUGFS_ATTRIBUTE(clk_set_parent_fops, NULL, clk_set_parent_set,
> > + "%llu\n");
> > +#endif
> > +
> > static int clk_duty_cycle_show(struct seq_file *s, void *data)
> > {
> > struct clk_core *core = s->private;
> > @@ -3285,9 +3309,14 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
> > debugfs_create_file("clk_parent", 0444, root, core,
> > ¤t_parent_fops);
> >
> > - if (core->num_parents > 1)
> > + if (core->num_parents > 1) {
> > debugfs_create_file("clk_possible_parents", 0444, root, core,
> > &possible_parents_fops);
> > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> > + debugfs_create_file("clk_set_parent", 0200, root, core,
> > + &clk_set_parent_fops);
> > +#endif
Why add a new file, instead of making the existing "clk_parent" file
writable, like is done for "clk_rate"?
Yes, "clk_parent" prints a name, while you use a parent number, but
I guess that can be fixed? Or even both can be accepted?
> > + }
> >
> > if (core->ops->debug_init)
> > core->ops->debug_init(core->hw, core->dentry);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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
Hi Geert,
On Tue, 5 Oct 2021 at 13:43, Geert Uytterhoeven <[email protected]> wrote:
>
> Hi Sam,
>
> On Tue, Oct 5, 2021 at 12:11 PM Sam Protsenko
> <[email protected]> wrote:
> > On Tue, 14 Sept 2021 at 17:19, Sam Protsenko <[email protected]> wrote:
> > > Useful for testing mux clocks. One can write the index of the parent to
> > > set into clk_set_parent node, starting from 0. Example
> > >
> > > # cat clk_possible_parrents
> > > dout_shared0_div4 dout_shared1_div4
> > > # cat clk_parent
> > > dout_shared0_div4
> > > # echo 1 > clk_set_parent
> > > # cat clk_parent
> > > dout_shared1_div4
> > >
> > > Define CLOCK_ALLOW_WRITE_DEBUGFS in drivers/clk/clk.c in order to use
> > > this feature.
> > >
> > > Signed-off-by: Sam Protsenko <[email protected]>
> > > ---
> >
> > + Adding more folks for review
> >
> > Guys, can you please review this one?
>
> Thanks for your patch!
>
Thanks for review! :)
> > > --- a/drivers/clk/clk.c
> > > +++ b/drivers/clk/clk.c
> > > @@ -3214,6 +3214,30 @@ static int current_parent_show(struct seq_file *s, void *data)
> > > }
> > > DEFINE_SHOW_ATTRIBUTE(current_parent);
> > >
> > > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> > > +static int clk_set_parent_set(void *data, u64 val)
>
> u64 is overkill, num_parents is u8.
>
u64 is required by simple_attr_open() signature, because
clk_set_parent_set() is being passed there as a parameter eventually
(via DEFINE_DEBUGFS_ATTRIBUTE()). But yeah, I'll use u8 when reworking
the code for using with existing 'clk_parent' file.
> > > +{
> > > + struct clk_core *core = data, *parent;
> > > + int ret;
> > > +
> > > + if (val >= core->num_parents)
> > > + return -EINVAL;
>
> clk_core_get_parent_by_index() called below already checks this.
>
Thanks, will remove this.
> > > +
> > > + parent = clk_core_get_parent_by_index(core, val);
> > > + if (IS_ERR_OR_NULL(parent))
> > > + return PTR_ERR(parent);
Also just noticed that this block is incorrect. I should've used just
'if (!parent)' here instead. I remember Russel King was raising the
question about removing that API for good, as too many people tend to
use that incorrectly, and now I can see why.
> > > +
> > > + clk_prepare_lock();
> > > + ret = clk_core_set_parent_nolock(core, parent);
> > > + clk_prepare_unlock();
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +DEFINE_DEBUGFS_ATTRIBUTE(clk_set_parent_fops, NULL, clk_set_parent_set,
> > > + "%llu\n");
> > > +#endif
> > > +
> > > static int clk_duty_cycle_show(struct seq_file *s, void *data)
> > > {
> > > struct clk_core *core = s->private;
> > > @@ -3285,9 +3309,14 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
> > > debugfs_create_file("clk_parent", 0444, root, core,
> > > ¤t_parent_fops);
> > >
> > > - if (core->num_parents > 1)
> > > + if (core->num_parents > 1) {
> > > debugfs_create_file("clk_possible_parents", 0444, root, core,
> > > &possible_parents_fops);
> > > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> > > + debugfs_create_file("clk_set_parent", 0200, root, core,
> > > + &clk_set_parent_fops);
> > > +#endif
>
> Why add a new file, instead of making the existing "clk_parent" file
> writable, like is done for "clk_rate"?
> Yes, "clk_parent" prints a name, while you use a parent number, but
> I guess that can be fixed? Or even both can be accepted?
>
Ok, I'll merge that feature into existing 'clk_parent' file. At the
time I implemented this I was busy with something else, and use
existing code around as an example. But it's not too hard to do this
properly, by defining 'struct file_operations' manually, like it's
done for example in dwc3_lsp_write(). Will send v2 with fixes shortly.
> > > + }
> > >
> > > if (core->ops->debug_init)
> > > core->ops->debug_init(core->hw, core->dentry);
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
>
> 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