| Message ID | 20181119141259.11992-1-phil.edworthy@renesas.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | clk: Add (devm_)clk_get_optional() functions | expand |
On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote: > This adds clk_get_optional() and devm_clk_get_optional() functions to get > optional clocks. > They behave the same as (devm_)clk_get except where there is no clock > producer. In this case, instead of returning -ENOENT, the function > returns NULL. This makes error checking simpler and allows > clk_prepare_enable, etc to be called on the returned reference > without additional checks. > - Instead of messing with the core functions, simply wrap them for the > _optional() versions. By putting clk_get_optional() inline in the header > file, we can get rid of the arch specific patches as well. Fine if it would have no surprises with error handling. > + if (ERR_PTR(-ENOENT)) > + return NULL; > + else > + return clk; return clk == ERR_PTR(-ENOENT) ? NULL : clk; ? > + if (clk == ERR_PTR(-ENOENT)) > + return NULL; > + else > + return clk; Ditto.
Hi Andy, On 20 November 2018 10:39 Andy Shevchenko wrote: > On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote: > > This adds clk_get_optional() and devm_clk_get_optional() functions to > > get optional clocks. > > They behave the same as (devm_)clk_get except where there is no clock > > producer. In this case, instead of returning -ENOENT, the function > > returns NULL. This makes error checking simpler and allows > > clk_prepare_enable, etc to be called on the returned reference without > > additional checks. > > > - Instead of messing with the core functions, simply wrap them for the > > _optional() versions. By putting clk_get_optional() inline in the header > > file, we can get rid of the arch specific patches as well. > > Fine if it would have no surprises with error handling. There shouldn't be any surprises. My earlier attempts at implementing this were hampered by the fact that of_clk_get_by_name() can return -EINVAL in some circumstances. By directly wrapping the (devm_)clk_get() functions that problem goes away. > > + if (ERR_PTR(-ENOENT)) Huh? That wasn't the code I sent... > > + return NULL; > > + else > > + return clk; > > return clk == ERR_PTR(-ENOENT) ? NULL : clk; > > ? > > > + if (clk == ERR_PTR(-ENOENT)) > > + return NULL; > > + else > > + return clk; > > Ditto. Sure, will fix both. Thanks Phil
On Tue, Nov 20, 2018 at 10:53:33AM +0000, Phil Edworthy wrote: > On 20 November 2018 10:39 Andy Shevchenko wrote: > > On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote: > > > This adds clk_get_optional() and devm_clk_get_optional() functions to > > > get optional clocks. > > > They behave the same as (devm_)clk_get except where there is no clock > > > producer. In this case, instead of returning -ENOENT, the function > > > returns NULL. This makes error checking simpler and allows > > > clk_prepare_enable, etc to be called on the returned reference without > > > additional checks. > > > - Instead of messing with the core functions, simply wrap them for the > > > _optional() versions. By putting clk_get_optional() inline in the header > > > file, we can get rid of the arch specific patches as well. > > Fine if it would have no surprises with error handling. > There shouldn't be any surprises. My earlier attempts at implementing this > were hampered by the fact that of_clk_get_by_name() can return -EINVAL > in some circumstances. By directly wrapping the (devm_)clk_get() functions > that problem goes away. Good! After my comments being addressed, Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > + if (ERR_PTR(-ENOENT)) > Huh? That wasn't the code I sent... Yup, it's my wrong editing flow. Anyway, you got the idea. > > > + return NULL; > > > + else > > > + return clk; > > return clk == ERR_PTR(-ENOENT) ? NULL : clk;
Hello, On Tue, Nov 20, 2018 at 12:38:33PM +0200, Andy Shevchenko wrote: > On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote: > > + if (clk == ERR_PTR(-ENOENT)) > > + return NULL; > > + else > > + return clk; > > return clk == ERR_PTR(-ENOENT) ? NULL : clk; > > ? Not sure this adds to the readability of the expression. Personally I prefer the explicit if. Maybe even: clk = clk_get(...); if (clk == ERR_PTR(-ENOENT)) clk = NULL; return clk; Best regards Uwe
On Tue, Nov 20, 2018 at 01:56:52PM +0100, Uwe Kleine-König wrote: > On Tue, Nov 20, 2018 at 12:38:33PM +0200, Andy Shevchenko wrote: > > On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote: > > > + if (clk == ERR_PTR(-ENOENT)) > > > + return NULL; > > > + else > > > + return clk; > > > > return clk == ERR_PTR(-ENOENT) ? NULL : clk; > > > > ? > > Not sure this adds to the readability of the expression. Personally I > prefer the explicit if. Maybe even: > > clk = clk_get(...); > > if (clk == ERR_PTR(-ENOENT)) > clk = NULL; > > return clk; So, it almost repeats the initial variant. I'm fine with no 'else' in initial code, like if (...) return NULL; return clk;
diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c index 12c87457eca1..f0033d937c39 100644 --- a/drivers/clk/clk-devres.c +++ b/drivers/clk/clk-devres.c @@ -34,6 +34,17 @@ struct clk *devm_clk_get(struct device *dev, const char *id) } EXPORT_SYMBOL(devm_clk_get); +struct clk *devm_clk_get_optional(struct device *dev, const char *id) +{ + struct clk *clk = devm_clk_get(dev, id); + + if (clk == ERR_PTR(-ENOENT)) + return NULL; + else + return clk; +} +EXPORT_SYMBOL(devm_clk_get_optional); + struct clk_bulk_devres { struct clk_bulk_data *clks; int num_clks; diff --git a/include/linux/clk.h b/include/linux/clk.h index a7773b5c0b9f..c7bbb0678057 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -383,6 +383,17 @@ int __must_check devm_clk_bulk_get_all(struct device *dev, */ struct clk *devm_clk_get(struct device *dev, const char *id); +/** + * devm_clk_get_optional - lookup and obtain a managed reference to an optional + * clock producer. + * @dev: device for clock "consumer" + * @id: clock consumer ID + * + * Behaves the same as devm_clk_get except where there is no clock producer. In + * this case, instead of returning -ENOENT, the function returns NULL. + */ +struct clk *devm_clk_get_optional(struct device *dev, const char *id); + /** * devm_get_clk_from_child - lookup and obtain a managed reference to a * clock producer from child node. @@ -718,6 +729,12 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id) return NULL; } +static inline struct clk *devm_clk_get_optional(struct device *dev, + const char *id) +{ + return NULL; +} + static inline int __must_check devm_clk_bulk_get(struct device *dev, int num_clks, struct clk_bulk_data *clks) { @@ -862,6 +879,16 @@ static inline void clk_bulk_disable_unprepare(int num_clks, clk_bulk_unprepare(num_clks, clks); } +static inline struct clk *clk_get_optional(struct device *dev, const char *id) +{ + struct clk *clk = clk_get(dev, id); + + if (clk == ERR_PTR(-ENOENT)) + return NULL; + else + return clk; +} + #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) struct clk *of_clk_get(struct device_node *np, int index); struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
This adds clk_get_optional() and devm_clk_get_optional() functions to get optional clocks. They behave the same as (devm_)clk_get except where there is no clock producer. In this case, instead of returning -ENOENT, the function returns NULL. This makes error checking simpler and allows clk_prepare_enable, etc to be called on the returned reference without additional checks. Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> --- v7: - Instead of messing with the core functions, simply wrap them for the _optional() versions. By putting clk_get_optional() inline in the header file, we can get rid of the arch specific patches as well. v6: - Add doxygen style comment for devm_clk_get_optional() args v5: - No changes. v4: - No changes. v3: - No changes. --- drivers/clk/clk-devres.c | 11 +++++++++++ include/linux/clk.h | 27 +++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)