From a442e61e245824f2cf7d7cf43844ac90e5d7e7a4 Mon Sep 17 00:00:00 2001
From: Patrick Delaunay <patrick.delaunay@st.com>
Date: Thu, 7 Mar 2019 09:57:13 +0100
Subject: [PATCH] syscon: update syscon_regmap_lookup_by_phandle

Change the function syscon_regmap_lookup_by_phandle()
introduced by commit 6c3af1f24e4b ("syscon: dm: Add a
new method to get a regmap from DTS") to have
Linux-compatible syscon API.

Same modification than commit e151a1c288bd ("syscon: add
Linux-compatible syscon API") solves issue when the node
identified by the phandle has several compatibles and is
already bound to a dedicated driver.

See Linux commit bdb0066df96e ("mfd: syscon: Decouple syscon
interface from platform devices").

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 arch/sandbox/dts/test.dts    |  3 +-
 drivers/core/syscon-uclass.c | 83 +++++++++++++++++++++++++-----------
 test/dm/syscon.c             |  7 +++
 3 files changed, 68 insertions(+), 25 deletions(-)

diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 87d8e5bcc9..6d4134c053 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -493,6 +493,7 @@
 			compatible = "denx,u-boot-probe-test";
 			first-syscon = <&syscon0>;
 			second-sys-ctrl = <&another_system_controller>;
+			third-syscon = <&syscon2>;
 		};
 	};
 
@@ -597,7 +598,7 @@
 			0x38 8>;
 	};
 
-	syscon@2 {
+	syscon2: syscon@2 {
 		compatible = "simple-mfd", "syscon";
 		reg = <0x40 5
 			0x48 6
diff --git a/drivers/core/syscon-uclass.c b/drivers/core/syscon-uclass.c
index afac6d6e37..5bb38e329c 100644
--- a/drivers/core/syscon-uclass.c
+++ b/drivers/core/syscon-uclass.c
@@ -57,18 +57,64 @@ static int syscon_pre_probe(struct udevice *dev)
 #endif
 }
 
+static int syscon_probe_by_ofnode(ofnode node, struct udevice **devp)
+{
+	struct udevice *dev, *parent;
+	int ret;
+
+	/* found node with "syscon" compatible, not bounded to SYSCON UCLASS */
+	if (!ofnode_device_is_compatible(node, "syscon")) {
+		dev_dbg(dev, "invalid compatible for syscon device\n");
+		return -EINVAL;
+	}
+
+	/* bound to driver with same ofnode or to root if not found */
+	if (device_find_global_by_ofnode(node, &parent))
+		parent = dm_root();
+
+	/* force bound to syscon class */
+	ret = device_bind_driver_to_node(parent, "syscon",
+					 ofnode_get_name(node),
+					 node, &dev);
+	if (ret) {
+		dev_dbg(dev, "unable to bound syscon device\n");
+		return ret;
+	}
+	ret = device_probe(dev);
+	if (ret) {
+		dev_dbg(dev, "unable to probe syscon device\n");
+		return ret;
+	}
+
+	*devp = dev;
+	return 0;
+}
+
 struct regmap *syscon_regmap_lookup_by_phandle(struct udevice *dev,
 					       const char *name)
 {
 	struct udevice *syscon;
 	struct regmap *r;
+	u32 phandle;
+	ofnode node;
 	int err;
 
 	err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
 					   name, &syscon);
 	if (err) {
-		dev_dbg(dev, "unable to find syscon device\n");
-		return ERR_PTR(err);
+		/* found node with "syscon" compatible, not bounded to SYSCON */
+		err = ofnode_read_u32(dev_ofnode(dev), name, &phandle);
+		if (err)
+			return ERR_PTR(err);
+
+		node = ofnode_get_by_phandle(phandle);
+		if (!ofnode_valid(node)) {
+			dev_dbg(dev, "unable to find syscon device\n");
+			return ERR_PTR(-EINVAL);
+		}
+		err = syscon_probe_by_ofnode(node, &syscon);
+		if (err)
+			return ERR_PTR(-ENODEV);
 	}
 
 	r = syscon_get_regmap(syscon);
@@ -152,29 +198,18 @@ U_BOOT_DRIVER(generic_syscon) = {
  */
 struct regmap *syscon_node_to_regmap(ofnode node)
 {
-	struct udevice *dev, *parent;
-	int ret;
+	struct udevice *dev;
+	struct regmap *r;
 
-	if (!uclass_get_device_by_ofnode(UCLASS_SYSCON, node, &dev))
-		return syscon_get_regmap(dev);
+	if (uclass_get_device_by_ofnode(UCLASS_SYSCON, node, &dev))
+		if (syscon_probe_by_ofnode(node, &dev))
+			return ERR_PTR(-ENODEV);
 
-	if (!ofnode_device_is_compatible(node, "syscon"))
-		return ERR_PTR(-EINVAL);
+	r = syscon_get_regmap(dev);
+	if (!r) {
+		dev_dbg(dev, "unable to find regmap\n");
+		return ERR_PTR(-ENODEV);
+	}
 
-	/* bound to driver with same ofnode or to root if not found */
-	if (device_find_global_by_ofnode(node, &parent))
-		parent = dm_root();
-
-	/* force bound to syscon class */
-	ret = device_bind_driver_to_node(parent, "syscon",
-					 ofnode_get_name(node),
-					 node, &dev);
-	if (ret)
-		return ERR_PTR(ret);
-
-	ret = device_probe(dev);
-	if (ret)
-		return ERR_PTR(ret);
-
-	return syscon_get_regmap(dev);
+	return r;
 }
diff --git a/test/dm/syscon.c b/test/dm/syscon.c
index a294dda02e..0ff9da7ec6 100644
--- a/test/dm/syscon.c
+++ b/test/dm/syscon.c
@@ -67,6 +67,13 @@ static int dm_test_syscon_by_phandle(struct unit_test_state *uts)
 	ut_assert(!IS_ERR(map));
 	ut_asserteq(4, map->range_count);
 
+	ut_assertok_ptr(syscon_regmap_lookup_by_phandle(dev,
+							"third-syscon"));
+	map = syscon_regmap_lookup_by_phandle(dev, "third-syscon");
+	ut_assert(map);
+	ut_assert(!IS_ERR(map));
+	ut_asserteq(4, map->range_count);
+
 	ut_assert(IS_ERR(syscon_regmap_lookup_by_phandle(dev, "not-present")));
 
 	return 0;