Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 5 Oct 2021 12:43:08 +0200 | Subject | Re: [PATCH] clk: Add clk_set_parent debugfs node |
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Hi Sam,
On Tue, Oct 5, 2021 at 12:11 PM Sam Protsenko <semen.protsenko@linaro.org> wrote: > On Tue, 14 Sept 2021 at 17:19, Sam Protsenko <semen.protsenko@linaro.org> 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 <semen.protsenko@linaro.org> > > --- > > + 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 -- 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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