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 <drink...@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
Reviewed-by: Matthias Brugger <matthias....@gmail.com>
---
Changes in v2:
- Add Matthias r-b tag.
- Add the explanation from the patch description to the code.
- Return NULL instead of -ENOTSUPP when regmap helpers are not enabled.
drivers/mfd/syscon.c | 18 ++++++++++++++++++
include/linux/mfd/syscon.h | 11 +++++++++++
2 files changed, 29 insertions(+)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index ca465794ea9c..c6f139b2e0c0 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -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;
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 7f20e9b502a5..fecc2fa2a364 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -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__ */
--
2.28.0
