[PATCH v2 1/3] mfd: syscon: Removed support for unloading

[PATCH v2 1/3] mfd: syscon: Removed support for unloading

[Alexander Shiyan]

The driver can be used in various subsystems and therefore should not
be unloaded when it is defined in the kernel configuration, so remove
support for unloading it.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/mfd/syscon.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 3f10591..e1886fb 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -138,17 +138,6 @@ static int syscon_probe(struct platform_device *pdev)
 	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 struct platform_driver syscon_driver = {
 	.driver = {
 		.name = "syscon",
@@ -156,7 +145,6 @@ static struct platform_driver syscon_driver = {
 		.of_match_table = of_syscon_match,
 	},
 	.probe		= syscon_probe,
-	.remove		= syscon_remove,
 };
 
 static int __init syscon_init(void)
@@ -165,12 +153,6 @@ static int __init syscon_init(void)
 }
 postcore_initcall(syscon_init);
 
-static void __exit syscon_exit(void)
-{
-	platform_driver_unregister(&syscon_driver);
-}
-module_exit(syscon_exit);
-
 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 MODULE_DESCRIPTION("System Control driver");
 MODULE_LICENSE("GPL v2");
-- 
1.7.12.4

[PATCH v2 2/3] mfd: syscon: Removed unneeded field "dev" from private driver structure

[Alexander Shiyan]

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/mfd/syscon.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index e1886fb..4a7ed5a 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -24,17 +24,15 @@
 static struct platform_driver syscon_driver;
 
 struct syscon {
-	struct device *dev;
 	void __iomem *base;
 	struct regmap *regmap;
 };
 
 static int syscon_match(struct device *dev, void *data)
 {
-	struct syscon *syscon = dev_get_drvdata(dev);
 	struct device_node *dn = data;
 
-	return (syscon->dev->of_node == dn) ? 1 : 0;
+	return (dev->of_node == dn) ? 1 : 0;
 }
 
 struct regmap *syscon_node_to_regmap(struct device_node *np)
@@ -129,7 +127,6 @@ static int syscon_probe(struct platform_device *pdev)
 		return PTR_ERR(syscon->regmap);
 	}
 
-	syscon->dev = dev;
 	platform_set_drvdata(pdev, syscon);
 
 	dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
-- 
1.7.12.4

[PATCH v2 3/3] mfd: syscon: Add non-DT support

[Alexander Shiyan]

This patch allow using syscon driver from the platform data, i.e.
possibility works without oftree support.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/mfd/Kconfig        |  1 -
 drivers/mfd/syscon.c       | 77 ++++++++++++++++++++++++++++++++++------------
 include/linux/mfd/syscon.h |  4 +++
 3 files changed, 62 insertions(+), 20 deletions(-)

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 671f5b1..8fdd87e 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1070,7 +1070,6 @@ 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
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 4a7ed5a..eac023e 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -21,6 +21,8 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 
+#include <linux/mfd/syscon.h>
+
 static struct platform_driver syscon_driver;
 
 struct syscon {
@@ -28,7 +30,7 @@ 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;
 
@@ -41,7 +43,7 @@ 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);
 
@@ -51,19 +53,40 @@ struct regmap *syscon_node_to_regmap(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 
+static int syscon_match_pdata(struct device *dev, void *data)
+{
+	struct syscon_pdata *pdata = dev_get_platdata(dev);
+
+	if (pdata)
+		return !strcmp(pdata->compatible, (const char *)data);
+
+	return 0;
+}
+
 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 {
 	struct device_node *syscon_np;
 	struct regmap *regmap;
+	struct syscon *syscon;
+	struct device *dev;
 
 	syscon_np = of_find_compatible_node(NULL, NULL, s);
-	if (!syscon_np)
+	if (syscon_np) {
+		regmap = syscon_node_to_regmap(syscon_np);
+		of_node_put(syscon_np);
+
+		return regmap;
+	}
+
+	/* Fallback to search by platform_data.compatible string */
+	dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
+				 syscon_match_pdata);
+	if (!dev)
 		return ERR_PTR(-ENODEV);
 
-	regmap = syscon_node_to_regmap(syscon_np);
-	of_node_put(syscon_np);
+	syscon = dev_get_drvdata(dev);
 
-	return regmap;
+	return syscon->regmap;
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 
@@ -100,37 +123,53 @@ 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;
+	struct resource *res, res_of;
 	int ret;
 
-	if (!np)
-		return -ENOENT;
-
 	syscon = devm_kzalloc(dev, sizeof(struct syscon),
 			    GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;
 
-	syscon->base = of_iomap(np, 0);
-	if (!syscon->base)
-		return -EADDRNOTAVAIL;
-
-	ret = of_address_to_resource(np, 0, &res);
-	if (ret)
-		return ret;
+	if (IS_ENABLED(CONFIG_OF) && np) {
+		syscon->base = of_iomap(np, 0);
+		if (!syscon->base)
+			return -EADDRNOTAVAIL;
+
+		res = &res_of;
+		ret = of_address_to_resource(np, 0, res);
+		if (ret) {
+			iounmap(syscon->base);
+			return ret;
+		}
+	} else {
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return -ENOENT;
+
+		if (!devm_request_mem_region(dev, res->start,
+					     resource_size(res),
+					     dev_name(&pdev->dev)))
+			return -EBUSY;
+
+		syscon->base = ioremap(res->start, resource_size(res));
+		if (!syscon->base)
+			return -EADDRNOTAVAIL;
+	}
 
-	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)) {
 		dev_err(dev, "regmap init failed\n");
+		iounmap(syscon->base);
 		return PTR_ERR(syscon->regmap);
 	}
 
 	platform_set_drvdata(pdev, syscon);
 
 	dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
-		res.start, res.end);
+		res->start, res->end);
 
 	return 0;
 }
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 6aeb6b8..96c2566 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -15,6 +15,10 @@
 #ifndef __LINUX_MFD_SYSCON_H__
 #define __LINUX_MFD_SYSCON_H__
 
+struct syscon_pdata {
+	const char	*compatible;
+};
+
 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_phandle(
-- 
1.7.12.4

Re: [PATCH v2 1/3] mfd: syscon: Removed support for unloading

[Arnd Bergmann]

On Monday 11 February 2013, Alexander Shiyan wrote:
> The driver can be used in various subsystems and therefore should not
> be unloaded when it is defined in the kernel configuration, so remove
> support for unloading it.
> 
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>

Can you describe a scenario where that would happen? Normally the
module should stay pinned as long as any other module refers
to its exported symbols.

	Arnd

Re[2]: [PATCH v2 1/3] mfd: syscon: Removed support for unloading

[Alexander Shiyan]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=utf-8, Size: 799 bytes --]

Hello.

> On Monday 11 February 2013, Alexander Shiyan wrote:
> > The driver can be used in various subsystems and therefore should not
> > be unloaded when it is defined in the kernel configuration, so remove
> > support for unloading it.
> > 
> > Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> 
> Can you describe a scenario where that would happen? Normally the
> module should stay pinned as long as any other module refers
> to its exported symbols.

Probably I wrote a bad description.
The driver registered by "postcore_initcall". Therefore, if we unregister the
driver, we have no way to register it back. Fixme please.

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Re: Re[2]: [PATCH v2 1/3] mfd: syscon: Removed support for unloading

[Arnd Bergmann]

On Tuesday 12 February 2013, Alexander Shiyan wrote:
> > On Monday 11 February 2013, Alexander Shiyan wrote:
> > > The driver can be used in various subsystems and therefore should not
> > > be unloaded when it is defined in the kernel configuration, so remove
> > > support for unloading it.
> > > 
> > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> > 
> > Can you describe a scenario where that would happen? Normally the
> > module should stay pinned as long as any other module refers
> > to its exported symbols.
> 
> Probably I wrote a bad description.
> The driver registered by "postcore_initcall". Therefore, if we unregister the
> driver, we have no way to register it back. Fixme please.

Ah, the driver is actually "bool" in Kconfig rather than "tristate", so
it is not possible to build it as a module. Makes sense then, and if 
we ever want to turn this into a module, we can still revert your patch.

	Arnd

Re: [PATCH v2 1/3] mfd: syscon: Removed support for unloading

[Dong Aisheng]

On 12 February 2013 02:42, Alexander Shiyan <shc_work@mail.ru> wrote:
> The driver can be used in various subsystems and therefore should not
> be unloaded when it is defined in the kernel configuration, so remove
> support for unloading it.
>
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>

Acked-by: Dong Aisheng <dong.aisheng@linaro.org>

Regards
Dong Aisheng

> ---
>  drivers/mfd/syscon.c | 18 ------------------
>  1 file changed, 18 deletions(-)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index 3f10591..e1886fb 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -138,17 +138,6 @@ static int syscon_probe(struct platform_device *pdev)
>         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 struct platform_driver syscon_driver = {
>         .driver = {
>                 .name = "syscon",
> @@ -156,7 +145,6 @@ static struct platform_driver syscon_driver = {
>                 .of_match_table = of_syscon_match,
>         },
>         .probe          = syscon_probe,
> -       .remove         = syscon_remove,
>  };
>
>  static int __init syscon_init(void)
> @@ -165,12 +153,6 @@ static int __init syscon_init(void)
>  }
>  postcore_initcall(syscon_init);
>
> -static void __exit syscon_exit(void)
> -{
> -       platform_driver_unregister(&syscon_driver);
> -}
> -module_exit(syscon_exit);
> -
>  MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
>  MODULE_DESCRIPTION("System Control driver");
>  MODULE_LICENSE("GPL v2");
> --
> 1.7.12.4
>

Re: [PATCH v2 2/3] mfd: syscon: Removed unneeded field "dev" from private driver structure

[Dong Aisheng]

On 12 February 2013 02:42, Alexander Shiyan <shc_work@mail.ru> wrote:
>
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>

Acked-by: Dong Aisheng <dong.aisheng@linaro.org>

Regards
Dong Aisheng

> ---
>  drivers/mfd/syscon.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index e1886fb..4a7ed5a 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -24,17 +24,15 @@
>  static struct platform_driver syscon_driver;
>
>  struct syscon {
> -       struct device *dev;
>         void __iomem *base;
>         struct regmap *regmap;
>  };
>
>  static int syscon_match(struct device *dev, void *data)
>  {
> -       struct syscon *syscon = dev_get_drvdata(dev);
>         struct device_node *dn = data;
>
> -       return (syscon->dev->of_node == dn) ? 1 : 0;
> +       return (dev->of_node == dn) ? 1 : 0;
>  }
>
>  struct regmap *syscon_node_to_regmap(struct device_node *np)
> @@ -129,7 +127,6 @@ static int syscon_probe(struct platform_device *pdev)
>                 return PTR_ERR(syscon->regmap);
>         }
>
> -       syscon->dev = dev;
>         platform_set_drvdata(pdev, syscon);
>
>         dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
> --
> 1.7.12.4
>