mfd: syscon: Add non-DT support

This patch allow using syscon driver from the platform data, i.e.
possibility using driver on systems without oftree support.
For search syscon device from the client drivers,
"syscon_regmap_lookup_by_pdevname" function was added.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/Kconfig

@@ -1100,7 +1100,6 @@ config MFD_STA2X11
 
 config MFD_SYSCON
 	bool "System Controller Register R/W Based on Regmap"
-	depends on OF
 	select REGMAP_MMIO
 	help
 	  Select this option to enable accessing system control registers

drivers/mfd/syscon.c

@@ -29,7 +29,7 @@ struct syscon {
 	struct regmap *regmap;
 };
 
-static int syscon_match(struct device *dev, void *data)
+static int syscon_match_node(struct device *dev, void *data)
 {
 	struct device_node *dn = data;
 
@@ -42,7 +42,7 @@ struct regmap *syscon_node_to_regmap(struct device_node *np)
 	struct device *dev;
 
 	dev = driver_find_device(&syscon_driver.driver, NULL, np,
-				 syscon_match);
+				 syscon_match_node);
 	if (!dev)
 		return ERR_PTR(-EPROBE_DEFER);
 
@@ -68,6 +68,34 @@ struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 
+static int syscon_match_pdevname(struct device *dev, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	const struct platform_device_id *id = platform_get_device_id(pdev);
+
+	if (id)
+		if (!strcmp(id->name, (const char *)data))
+			return 1;
+
+	return !strcmp(dev_name(dev), (const char *)data);
+}
+
+struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
+{
+	struct device *dev;
+	struct syscon *syscon;
+
+	dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
+				 syscon_match_pdevname);
+	if (!dev)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	syscon = dev_get_drvdata(dev);
+
+	return syscon->regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
+
 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 					const char *property)
 {
@@ -99,28 +127,22 @@ static struct regmap_config syscon_regmap_config = {
 static int syscon_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
 	struct syscon *syscon;
-	struct resource res;
-	int ret;
-
-	if (!np)
-		return -ENOENT;
+	struct resource *res;
 
-	syscon = devm_kzalloc(dev, sizeof(struct syscon),
-			    GFP_KERNEL);
+	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;
 
-	syscon->base = of_iomap(np, 0);
-	if (!syscon->base)
-		return -EADDRNOTAVAIL;
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENOENT;
 
-	ret = of_address_to_resource(np, 0, &res);
-	if (ret)
-		return ret;
+	syscon->base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!syscon->base)
+		return -ENOMEM;
 
-	syscon_regmap_config.max_register = res.end - res.start - 3;
+	syscon_regmap_config.max_register = res->end - res->start - 3;
 	syscon->regmap = devm_regmap_init_mmio(dev, syscon->base,
 					&syscon_regmap_config);
 	if (IS_ERR(syscon->regmap)) {
@@ -130,22 +152,15 @@ static int syscon_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, syscon);
 
-	dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
-		res.start, res.end);
+	dev_info(dev, "regmap 0x%x-0x%x registered\n", res->start, res->end);
 
 	return 0;
 }
 
-static int syscon_remove(struct platform_device *pdev)
-{
-	struct syscon *syscon;
-
-	syscon = platform_get_drvdata(pdev);
-	iounmap(syscon->base);
-	platform_set_drvdata(pdev, NULL);
-
-	return 0;
-}
+static const struct platform_device_id syscon_ids[] = {
+	{ "syscon", },
+	{ }
+};
 
 static struct platform_driver syscon_driver = {
 	.driver = {
@@ -154,7 +169,7 @@ static struct platform_driver syscon_driver = {
 		.of_match_table = of_syscon_match,
 	},
 	.probe		= syscon_probe,
-	.remove		= syscon_remove,
+	.id_table	= syscon_ids,
 };
 
 static int __init syscon_init(void)

include/linux/mfd/syscon.h

@@ -17,6 +17,7 @@
 
 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_pdevname(const char *s);
 extern struct regmap *syscon_regmap_lookup_by_phandle(
 					struct device_node *np,
 					const char *property);