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mfd: syscon: Add syscon_regmap_lookup_by_phandle_optional() function. 

This adds syscon_regmap_lookup_by_phandle_optional() function to get an
optional regmap.

It behaves the same as syscon_regmap_lookup_by_phandle() except where
there is no regmap phandle. In this case, instead of returning -ENODEV,
the function returns NULL. This makes error checking simpler when the
regmap phandle is optional.

Suggested-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Enric Balletbo i Serra 2020-11-10 17:13:37 +01:00 committed by Lee Jones
parent 3650b228f8
commit 86b9d170da
2 changed files with 29 additions and 0 deletions
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18
drivers/mfd/syscon.c
View File

@ -255,6 +255,24 @@ struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
/*
* It behaves the same as syscon_regmap_lookup_by_phandle() except where
* there is no regmap phandle. In this case, instead of returning -ENODEV,
* the function returns NULL.
*/
struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
const char *property)
{
struct regmap *regmap;
regmap = syscon_regmap_lookup_by_phandle(np, property);
if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
return NULL;
return regmap;
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
static int syscon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;

11
include/linux/mfd/syscon.h
View File

@ -28,6 +28,9 @@ extern struct regmap *syscon_regmap_lookup_by_phandle_args(
const char *property,
int arg_count,
unsigned int *out_args);
extern struct regmap *syscon_regmap_lookup_by_phandle_optional(
struct device_node *np,
const char *property);
#else
static inline struct regmap *device_node_to_regmap(struct device_node *np)
{
@ -59,6 +62,14 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle_args(
{
return ERR_PTR(-ENOTSUPP);
}
static inline struct regmap *syscon_regmap_lookup_by_phandle_optional(
struct device_node *np,
const char *property)
{
return NULL;
}
#endif
#endif /* __LINUX_MFD_SYSCON_H__ */