mfd: syscon: implement device_node_to_regmap

Extend our syscon API with a device_node_to_regmap function that has the
same semantics as upstream:

 __________________________________________________________________________
| Linux commit 39233b7c611248c0d05209b4854bc63e26485655
| CommitDate: Thu Aug 8 15:30:07 2019 -0700
|
| mfd/syscon: Add device_node_to_regmap()
|
| device_node_to_regmap() is exactly like syscon_node_to_regmap(), but it
| does not check that the node is compatible with "syscon", and won't
| attach the first clock it finds to the regmap.
|
| 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
| devicetree.
|
| Signed-off-by: Paul Cercueil <paul@crapouillou.net>
| Acked-by: Arnd Bergmann <arnd@arndb.de>
| Signed-off-by: Paul Burton <paul.burton@mips.com>
|__________________________________________________________________________

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 16 insertions, 5 deletions

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index a8bb297bd2..38b25858ed 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -154,20 +154,31 @@ void __iomem *syscon_base_lookup_by_phandle(struct device_node *np,
 	return syscon_node_to_base(syscon_np);
 }
 
-struct regmap *syscon_node_to_regmap(struct device_node *np)
+static struct regmap *__device_node_to_regmap(struct device_node *np,
+					      bool check_clk)
 {
 	struct syscon *syscon;
 
-	if (!of_device_is_compatible(np, "syscon"))
-		return ERR_PTR(-EINVAL);
-
-	syscon = node_to_syscon(np, true);
+	syscon = node_to_syscon(np, check_clk);
 	if (IS_ERR(syscon))
 		return ERR_CAST(syscon);
 
 	return syscon->regmap;
 }
 
+struct regmap *device_node_to_regmap(struct device_node *np)
+{
+	return __device_node_to_regmap(np, false);
+}
+
+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, true);
+}
+
 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 {
 	struct device_node *syscon_np;