Messages in this thread Patch in this message | | | From | Heiko Stübner <> | Subject | Re: [PATCH v3 0/2] clk: improve handling of orphan clocks | Date | Fri, 01 May 2015 21:59:55 +0200 |
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Am Donnerstag, 30. April 2015, 17:19:01 schrieb Stephen Boyd: > On 04/22, Heiko Stuebner wrote: > > Using orphan clocks can introduce strange behaviour as they don't have > > rate information at all and also of course don't track > > > > This v2/v3 takes into account suggestions from Stephen Boyd to not try to > > walk the clock tree at runtime but instead keep track of orphan states > > on clock tree changes and making it mandatory for everybody from the > > start as orphaned clocks should not be used at all. > > > > > > This fixes an issue on most rk3288 platforms, where some soc-clocks > > are supplied by a 32khz clock from an external i2c-chip which often > > is only probed later in the boot process and maybe even after the > > drivers using these soc-clocks like the tsadc temperature sensor. > > In this case the driver using the clock should of course defer probing > > until the clock is actually usable. > > > > > > As this changes the behaviour for orphan clocks, it would of course > > benefit from more testing than on my Rockchip boards. To keep the > > recipent-list reasonable and not spam to much I selected one (the topmost) > > from the get_maintainer output of each drivers/clk entry. > > Hopefully some will provide Tested-by-tags :-) > > <grumble> I don't see any Tested-by: tags yet </grumble>. I've > put these two patches on a separate branch "defer-orphans" and > pushed it to clk-next so we can give it some more exposure. > > Unfortunately this doesn't solve the orphan problem for non-OF > providers. What if we did the orphan check in __clk_create_clk() > instead and returned an error pointer for orphans? I suspect that > will solve all cases, right?
hmm, clk_register also uses __clk_create_clk, which in turn would prevent registering orphan-clocks at all, I'd think. As on my platform I'm dependant on orphan clocks (the soc-level clock gets registerted as part of the big clock controller way before the i2c-based supplying clock), I'd rather not touch this :-) .
Instead I guess we could hook it less deep into clk_get_sys, like in the following patch?
------------ 8< ------------------------- >8 ----------------- From: Heiko Stuebner <heiko@sntech.de> Date: Fri, 1 May 2015 21:50:46 +0200 Subject: [PATCH] clk: prevent orphan access on non-devicetree platforms too
The orphan-check in __of_clk_get_from_provider only prevents orphan-access on devicetree platforms. To bring non-dt platforms to the same level of functionality let clk_get_sys (called from clk_get for non-dt platforms) also check for orphans and return -EPROBE_DEFER in that case.
Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- drivers/clk/clk.c | 2 +- drivers/clk/clk.h | 5 +++++ drivers/clk/clkdev.c | 5 +++++ 3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 36d1a01..167d0bf 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2220,7 +2220,7 @@ static inline void clk_debug_unregister(struct clk_core *core) } #endif -static bool clk_is_orphan(const struct clk *clk) +bool clk_is_orphan(const struct clk *clk) { if (!clk) return false; diff --git a/drivers/clk/clk.h b/drivers/clk/clk.h index 00b35a1..b8a6061 100644 --- a/drivers/clk/clk.h +++ b/drivers/clk/clk.h @@ -20,6 +20,7 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec, struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id, const char *con_id); void __clk_free_clk(struct clk *clk); +bool clk_is_orphan(const struct clk *clk); #else /* All these casts to avoid ifdefs in clkdev... */ static inline struct clk * @@ -32,5 +33,9 @@ static struct clk_hw *__clk_get_hw(struct clk *clk) { return (struct clk_hw *)clk; } +static inline bool clk_is_orphan(const struct clk *clk) +{ + return false; +} #endif diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index 1fcb6ef..ad96775 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -177,6 +177,11 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id) if (!cl) goto out; + if (clk_is_orphan(cl->clk)) { + clk = ERR_PTR(-EPROBE_DEFER); + goto out; + } + clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id); if (IS_ERR(clk)) goto out; -- 2.1.4
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