[PATCH] mfd: syscon: allow to register syscon with a device

[Philipp Zabel]

Commit bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform devices")
added the possibility to register syscon devices without associated platform
device. This also removed regmap debugfs facilities, which don't work without a
device. Since there is no replacement, this patch allows again to register
syscon regions with an associated device where that this device exists anyway.

[fixed max_register parameter in case of device register]
Signed-off-by: Peter Seiderer <ps.report@xxxxxxx>
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
 drivers/mfd/syscon.c       | 29 +++++++++++++++++++++--------
 include/linux/mfd/syscon.h | 10 ++++++++++
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 176bf0f..af0f899 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -36,19 +36,20 @@ struct syscon {
 	struct list_head list;
 };
 
-static struct regmap_config syscon_regmap_config = {
+static const struct regmap_config syscon_regmap_config = {
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
 };
 
-static struct syscon *of_syscon_register(struct device_node *np)
+struct syscon *syscon_register(struct device *dev, struct device_node *np)
 {
 	struct syscon *syscon;
 	struct regmap *regmap;
 	void __iomem *base;
 	int ret;
 	struct regmap_config syscon_config = syscon_regmap_config;
+	struct resource res;
 
 	if (!of_device_is_compatible(np, "syscon"))
 		return ERR_PTR(-EINVAL);
@@ -57,7 +58,12 @@ static struct syscon *of_syscon_register(struct device_node *np)
 	if (!syscon)
 		return ERR_PTR(-ENOMEM);
 
-	base = of_iomap(np, 0);
+	if (of_address_to_resource(np, 0, &res)) {
+		ret = -ENOMEM;
+		goto err_map;
+	}
+
+	base = ioremap(res.start, resource_size(&res));
 	if (!base) {
 		ret = -ENOMEM;
 		goto err_map;
@@ -69,7 +75,8 @@ static struct syscon *of_syscon_register(struct device_node *np)
 	 else if (of_property_read_bool(np, "little-endian"))
 		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
 
-	regmap = regmap_init_mmio(NULL, base, &syscon_config);
+	syscon_config.max_register = res.end - res.start - 3;
+	regmap = regmap_init_mmio(dev, base, &syscon_config);
 	if (IS_ERR(regmap)) {
 		pr_err("regmap init failed\n");
 		ret = PTR_ERR(regmap);
@@ -91,6 +98,12 @@ err_map:
 	kfree(syscon);
 	return ERR_PTR(ret);
 }
+EXPORT_SYMBOL_GPL(syscon_register);
+
+static struct syscon *of_syscon_register(struct device_node *np)
+{
+	return syscon_register(NULL, np);
+}
 
 struct regmap *syscon_node_to_regmap(struct device_node *np)
 {
@@ -179,6 +192,7 @@ static int syscon_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct syscon_platform_data *pdata = dev_get_platdata(dev);
 	struct syscon *syscon;
+	struct regmap_config syscon_config = syscon_regmap_config;
 	struct resource *res;
 	void __iomem *base;
 
@@ -194,11 +208,10 @@ static int syscon_probe(struct platform_device *pdev)
 	if (!base)
 		return -ENOMEM;
 
-	syscon_regmap_config.max_register = res->end - res->start - 3;
+	syscon_config.max_register = res->end - res->start - 3;
 	if (pdata)
-		syscon_regmap_config.name = pdata->label;
-	syscon->regmap = devm_regmap_init_mmio(dev, base,
-					&syscon_regmap_config);
+		syscon_config.name = pdata->label;
+	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 	if (IS_ERR(syscon->regmap)) {
 		dev_err(dev, "regmap init failed\n");
 		return PTR_ERR(syscon->regmap);
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 75e543b..e0c4a86 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -17,10 +17,14 @@
 
 #include <linux/err.h>
 
+struct device;
 struct device_node;
+struct syscon;
 
 #ifdef CONFIG_MFD_SYSCON
 extern struct regmap *syscon_node_to_regmap(struct device_node *np);
+extern struct syscon *syscon_register(struct device *dev,
+				      struct device_node *np);
 extern struct regmap *syscon_regmap_lookup_by_compatible(const char *s);
 extern struct regmap *syscon_regmap_lookup_by_pdevname(const char *s);
 extern struct regmap *syscon_regmap_lookup_by_phandle(
@@ -32,6 +36,12 @@ static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
 	return ERR_PTR(-ENOSYS);
 }
 
+static struct syscon *syscon_register(struct device *dev,
+				      struct device_node *np)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
 static inline struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 {
 	return ERR_PTR(-ENOSYS);
-- 
2.1.4

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