Re: [PATCH] mfd/syscon: Add device_node_to_regmap()

From: Paul Cercueil
Date: Tue Jul 23 2019 - 22:35:43 EST

Actually I'll make a revised version and merge it with a patchset that
makes use of this feature.


Le mar. 23 juil. 2019 à 14:55, Paul Cercueil <paul@xxxxxxxxxxxxxxx> a écrit :
device_node_to_regmap() is exactly like syscon_node_to_regmap(), but it
does not check that the node is compatible with "syscon".

The rationale behind this, is that one device node with a standard
compatible string "foo,bar" can be covered by multiple drivers sharing a
regmap, or by a single driver doing all the job without a regmap, but
these are implementation details which shouldn't reflect on the

Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
drivers/mfd/syscon.c | 14 ++++++++++----
include/linux/mfd/syscon.h | 6 ++++++
2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index b65e585fc8c6..3dcb56d4688d 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -51,9 +51,6 @@ static struct syscon *of_syscon_register(struct device_node *np)
struct regmap_config syscon_config = syscon_regmap_config;
struct resource res;

- if (!of_device_is_compatible(np, "syscon"))
- return ERR_PTR(-EINVAL);
syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
if (!syscon)
return ERR_PTR(-ENOMEM);
@@ -150,7 +147,7 @@ static struct syscon *of_syscon_register(struct device_node *np)
return ERR_PTR(ret);

-struct regmap *syscon_node_to_regmap(struct device_node *np)
+struct regmap *device_node_to_regmap(struct device_node *np)
struct syscon *entry, *syscon = NULL;

@@ -172,6 +169,15 @@ struct regmap *syscon_node_to_regmap(struct device_node *np)

return syscon->regmap;
+struct regmap *syscon_node_to_regmap(struct device_node *np)
+ if (!of_device_is_compatible(np, "syscon"))
+ return ERR_PTR(-EINVAL);
+ return device_node_to_regmap(np);

struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 8cfda0554381..112dc66262cc 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -17,12 +17,18 @@
struct device_node;

+extern struct regmap *device_node_to_regmap(struct device_node *np);
extern struct regmap *syscon_node_to_regmap(struct device_node *np);
extern struct regmap *syscon_regmap_lookup_by_compatible(const char *s);
extern struct regmap *syscon_regmap_lookup_by_phandle(
struct device_node *np,
const char *property);
+static inline struct regmap *device_node_to_regmap(struct device_node *np)
+ return ERR_PTR(-ENOTSUPP);
static inline struct regmap *syscon_node_to_regmap(struct device_node *np)