Re: [Cocci] [PATCH v13 3/6] clk: Make clk API return per-user struct clk instances

[Quentin Lambert]

Hello,
Julia asked me to have a look and see if I can help.

On 02/02/2015 23:50, Mike Turquette wrote:
> Quoting Stephen Boyd (2015-02-02 14:35:59)
> > On 02/02/15 13:31, Julia Lawall wrote:
> > > On Mon, 2 Feb 2015, Stephen Boyd wrote:
> > >
> > > > Julia,
> > > >
> > > > Is there a way we can write a coccinelle script to check for this? The
> > > > goal being to find all drivers that are comparing struct clk pointers or
> > > > attempting to dereference them. There are probably other frameworks that
> > > > could use the same type of check (regulator, gpiod, reset, pwm, etc.).
> > > > Probably anything that has a get/put API.
> > > Comparing or dereferencing pointers of a particular type should be
> > > straightforward to check for.  Is there an example of how to use the
> > > parent_index value to fix the problem?
> > I'm not sure how to fix this case with parent_index values generically.
> > I imagine it would be highly specific to the surrounding code to the
> > point where we couldn't fix it automatically. For example, if it's a clk
> > consumer (not provider like in this case) using an index wouldn't be the
> > right fix. We would need some sort of clk API that we don't currently
> > have and I would wonder why clock consumers even care to compare such
> > pointers in the first place.
> Ack. Is there precedent for a "Don't do that" kind of response?
>
> Regards,
> Mike
>
> > --
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> > a Linux Foundation Collaborative Project
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I have found these three cases using Coccinnelle in the mach-omap2
directory.



./arch/arm/mach-omap2/clkt_clksel.c
@@ -67,7 +67,6 @@ static const struct clksel *_get_clksel_
                return NULL;

        for (clks = clk->clksel; clks->parent; clks++)
                if (clks->parent == src_clk)
                        break; /* Found the requested parent */

        if (!clks->parent) {
./arch/arm/mach-omap2/dpll3xxx.c
@@ -551,7 +549,6 @@ int omap3_noncore_dpll_set_rate(struct c
        if (!dd)
                return -EINVAL;

        if (__clk_get_parent(hw->clk) != dd->clk_ref)
                return -EINVAL;

        if (dd->last_rounded_rate == 0)
./arch/arm/mach-omap2/timer.c
@@ -298,7 +298,6 @@ static int __init omap_dm_timer_init_one
        if (IS_ERR(src))
                return PTR_ERR(src);

        if (clk_get_parent(timer->fclk) != src) {
                r = clk_set_parent(timer->fclk, src);
                if (r < 0) {
                        pr_warn("%s: %s cannot set source\n", __func__,


Are they instances of your issue?
Do you have any suggestion on how to fix them?
If you want me to I can enlarge the search to other directories.


Quentin
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