Syscon early initialization

Create special function regmap_attach_dev which can be called separately out of regmap_init.

Some platforms need to get system controller ready as soon as possible.
The patch provides early_syscon_initialization which create early mapping for all syscon compatible devices in early_syscon_probe.
Regmap is get via syscon_early_regmap_lookup_by_phandle()

Regular device probes attach device to regmap via regmap_attach_dev().

For early syscon initialization is necessary to extend struct syscon and provide remove function which unmap all early init structures.

Signed-off-by Michal Simek <[email protected]>

---

 drivers/mfd/syscon.c       | 126 +++++++++++++++++++++++++++++++++++++++------
 include/linux/mfd/syscon.h |  11 ++++
 2 files changed, 120 insertions(+), 17 deletions(-)

drivers/mfd/syscon.c +96 -17

index 71841f9..5935f02 100644
@@ -20,12 +20,15 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/slab.h>
 #include <linux/mfd/syscon.h>
 
 static struct platform_driver syscon_driver;
 
 struct syscon {
+	void __iomem *base;
 	struct regmap *regmap;
+	struct resource res;
 };
 
 static int syscon_match_node(struct device *dev, void *data)

@@ -95,6 +98,24 @@ struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 
+struct regmap *syscon_early_regmap_lookup_by_phandle(struct device_node *np,
+						     const char *property)
+{
+	struct device_node *syscon_np;
+	struct syscon *syscon;
+
+	syscon_np = of_parse_phandle(np, property, 0);
+	if (!syscon_np)
+		return ERR_PTR(-ENODEV);
+
+	syscon = syscon_np->data;
+
+	of_node_put(syscon_np);
+
+	return syscon->regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_early_regmap_lookup_by_phandle);
+
 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 					const char *property)
 {

@@ -128,40 +149,110 @@ static int syscon_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct syscon *syscon;
 	struct resource *res;
-	void __iomem *base;
 
-	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
+	/* Early syscon init */
+	if (pdev->dev.of_node && pdev->dev.of_node->data) {
+		syscon = pdev->dev.of_node->data;
+		res = &syscon->res;
+		regmap_attach_dev(dev, syscon->regmap, &syscon_regmap_config);
+	} else {
+
+		syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
+		if (!syscon)
+			return -ENOMEM;
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return -ENOENT;
+
+		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 = devm_regmap_init_mmio(dev, syscon->base,
+						&syscon_regmap_config);
+		if (IS_ERR(syscon->regmap)) {
+			dev_err(dev, "regmap init failed\n");
+			return PTR_ERR(syscon->regmap);
+		}
+	}
+
+	platform_set_drvdata(pdev, syscon);
+
+	dev_info(dev, "regmap %pR registered\n", res);
+
+	return 0;
+}
+
+static const struct platform_device_id syscon_ids[] = {
+	{ "syscon", },
+	{ }
+};
+
+static int syscon_remove(struct platform_device *pdev)
+{
+	struct syscon *syscon = platform_get_drvdata(pdev);
+
+	if (pdev->dev.of_node && pdev->dev.of_node->data) {
+		iounmap(syscon->base);
+		kfree(syscon);
+	}
+
+	return 0;
+}
+
+static int early_syscon_probe(struct device_node *np)
+{
+	struct syscon *syscon;
+
+	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
-		return -ENOENT;
+	if (of_address_to_resource(np, 0, &syscon->res))
+		return -EINVAL;
 
-	base = devm_ioremap(dev, res->start, resource_size(res));
-	if (!base)
-		return -ENOMEM;
+	syscon->base = ioremap(syscon->res.start, resource_size(&syscon->res));
+	if (!syscon->base) {
+		pr_err("%s: Unable to map I/O memory\n", __func__);
+		return PTR_ERR(syscon->base);
+	}
 
-	syscon_regmap_config.max_register = res->end - res->start - 3;
-	syscon->regmap = devm_regmap_init_mmio(dev, base,
-					&syscon_regmap_config);
+	syscon_regmap_config.max_register = syscon->res.end -
+					    syscon->res.start - 3;
+	syscon->regmap = regmap_init_mmio(NULL, syscon->base,
+					  &syscon_regmap_config);
 	if (IS_ERR(syscon->regmap)) {
-		dev_err(dev, "regmap init failed\n");
+		pr_err("regmap init failed\n");
 		return PTR_ERR(syscon->regmap);
 	}
 
-	platform_set_drvdata(pdev, syscon);
+	np->data = syscon;
 
-	dev_info(dev, "regmap %pR registered\n", res);
+	of_node_put(np);
+
+	pr_info("%s: regmap %pR registered\n", np->full_name, &syscon->res);
 
 	return 0;
 }
 
-static const struct platform_device_id syscon_ids[] = {
-	{ "syscon", },
-	{ }
+static struct of_device_id of_syscon_ids[] = {

Some platforms need to get system controller ready as soon as possible.
The patch provides early_syscon_initialization which create early mapping for all syscon compatible devices in early_syscon_probe.
Regmap is get via syscon_early_regmap_lookup_by_phandle()

Regular device probes attach device to regmap via regmap_attach_dev().

For early syscon initialization is necessary to extend struct syscon and provide remove function which unmap all early init structures.

Signed-off-by Michal Simek <[email protected]>

---

 drivers/mfd/syscon.c       | 126 +++++++++++++++++++++++++++++++++++++++------
 include/linux/mfd/syscon.h |  11 ++++
 2 files changed, 120 insertions(+), 17 deletions(-)

drivers/mfd/syscon.c +0 -0

struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,

drivers/mfd/syscon.c +0 -0

 					const char *property)
 {

@@ -128,40 +149,110 @@ static int syscon_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;

drivers/mfd/syscon.c +82 -15

+	} else {
+
+		syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
+		if (!syscon)
+			return -ENOMEM;
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return -ENOENT;
+
+		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 = devm_regmap_init_mmio(dev, syscon->base,
+						&syscon_regmap_config);
+		if (IS_ERR(syscon->regmap)) {
+			dev_err(dev, "regmap init failed\n");
+			return PTR_ERR(syscon->regmap);
+		}
+	}
+	platform_set_drvdata(pdev, syscon);
+
+	dev_info(dev, "regmap %pR registered\n", res);
+
+	return 0;
+}
+
+static const struct platform_device_id syscon_ids[] = {
+	{ "syscon", },
+	{ }
+};
+
+static int syscon_remove(struct platform_device *pdev)
+{
+	struct syscon *syscon = platform_get_drvdata(pdev);
+
+	if (pdev->dev.of_node && pdev->dev.of_node->data) {
+		iounmap(syscon->base);
+		kfree(syscon);
+	}
+
+	return 0;
+}
+
+static int early_syscon_probe(struct device_node *np)
+{
+	struct syscon *syscon;
+
+	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
-		return -ENOENT;
+	if (of_address_to_resource(np, 0, &syscon->res))
+		return -EINVAL;
 
-	base = devm_ioremap(dev, res->start, resource_size(res));
-	if (!base)
-		return -ENOMEM;
+	syscon->base = ioremap(syscon->res.start, resource_size(&syscon->res));
+	if (!syscon->base) {
+		pr_err("%s: Unable to map I/O memory\n", __func__);
+		return PTR_ERR(syscon->base);
+	}
 
-	syscon_regmap_config.max_register = res->end - res->start - 3;
-	syscon->regmap = devm_regmap_init_mmio(dev, base,
-					&syscon_regmap_config);
+	syscon_regmap_config.max_register = syscon->res.end -
+					    syscon->res.start - 3;
+	syscon->regmap = regmap_init_mmio(NULL, syscon->base,
+					  &syscon_regmap_config);
 	if (IS_ERR(syscon->regmap)) {
-		dev_err(dev, "regmap init failed\n");
+		pr_err("regmap init failed\n");
 		return PTR_ERR(syscon->regmap);
 	}
 
-	platform_set_drvdata(pdev, syscon);
+	np->data = syscon;
 
-	dev_info(dev, "regmap %pR registered\n", res);
+	of_node_put(np);
+
+	pr_info("%s: regmap %pR registered\n", np->full_name, &syscon->res);
 
 	return 0;
 }
 
-static const struct platform_device_id syscon_ids[] = {
-	{ "syscon", },
-	{ }
+static struct of_device_id of_syscon_ids[] = {
+	{ .compatible = "syscon" },
+	{},
 };
 
+void __init early_syscon_init(void)
+{
+	struct device_node *np;
+
+	for_each_matching_node_and_match(np, of_syscon_ids, NULL) {
+		if (!early_syscon_probe(np))
+			BUG();
+	}
+}
+
 static struct platform_driver syscon_driver = {
 	.driver = {
 		.name = "syscon",

@@ -169,6 +260,7 @@ static struct platform_driver syscon_driver = {
 		.of_match_table = of_syscon_match,
 	},
 	.probe		= syscon_probe,
+	.remove		= syscon_remove,
 	.id_table	= syscon_ids,
 };
 

include/linux/mfd/syscon.h +11 -0

index 8789fa3..465c092 100644
@@ -24,6 +24,10 @@ 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);
+extern struct regmap *syscon_early_regmap_lookup_by_phandle(
+					struct device_node *np,
+					const char *property);
+extern void early_syscon_init(void);
 #else
 static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
 {

@@ -46,6 +50,13 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle(
 {
 	return ERR_PTR(-ENOSYS);
 }
+
+static struct regmap *syscon_early_regmap_lookup_by_phandle(
+					struct device_node *np,
+					const char *property)
+{
+	return ERR_PTR(-ENOSYS);
+}
 #endif
 
 #endif /* __LINUX_MFD_SYSCON_H__ */

Quoted 22 lines · Michal Simek

Some platforms need to get system controller ready as soon as possible.
The patch provides early_syscon_initialization which create early mapping for all syscon compatible devices in early_syscon_probe.
Regmap is get via syscon_early_regmap_lookup_by_phandle()

Regular device probes attach device to regmap via regmap_attach_dev().

For early syscon initialization is necessary to extend struct syscon and provide remove function which unmap all early init structures.

Signed-off-by Michal Simek <[email protected]>

---

 drivers/mfd/syscon.c       | 126 +++++++++++++++++++++++++++++++++++++++------
 include/linux/mfd/syscon.h |  11 ++++
 2 files changed, 120 insertions(+), 17 deletions(-)

drivers/mfd/syscon.c +0 -0

<snip>

Quoted 9 lines

struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,

drivers/mfd/syscon.c +0 -1

 					const char *property)
 {

@@ -128,40 +149,110 @@ static int syscon_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct syscon *syscon;
 	struct resource *res;
-	void __iomem *base;
 

drivers/mfd/syscon.c static int syscon_probe(struct platform_device *pdev) · line 157

Quoted 6 lines

drivers/mfd/syscon.c +5 -1

-	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
+	/* Early syscon init */
+	if (pdev->dev.of_node && pdev->dev.of_node->data) {
+		syscon = pdev->dev.of_node->data;
+		res = &syscon->res;
+		regmap_attach_dev(dev, syscon->regmap, &syscon_regmap_config);

Instead of duplicating all of the init code with early and late versions of each, is there any reason why we can't always do the early stuff early and then connect it to the dev infrastructure when it becomes available?