[RFC 1/3] OLPC: Use device tree for platform identification

[RFC 1/3] OLPC: Use device tree for platform identification

[Daniel Drake]

Make OLPC fully depend on device tree, and use it to identify the OLPC
platform details. Some nodes are exposed as platform devices where we
plan to use device tree for device probing.

Signed-off-by: Daniel Drake <dsd-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org>
---
 arch/x86/Kconfig                 |    2 +-
 arch/x86/include/asm/olpc_ofw.h  |    8 +----
 arch/x86/platform/olpc/Makefile  |    4 +--
 arch/x86/platform/olpc/olpc.c    |   51 ++++++++++++++++++++-----------------
 arch/x86/platform/olpc/olpc_dt.c |   15 +++++++++++
 5 files changed, 47 insertions(+), 33 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b4c2e9c..471221b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2071,7 +2071,7 @@ config OLPC
 	depends on !X86_PAE
 	select GPIOLIB
 	select OF
-	select OF_PROMTREE if PROC_DEVICETREE
+	select OF_PROMTREE
 	---help---
 	  Add support for detecting the unique features of the OLPC
 	  XO hardware.
diff --git a/arch/x86/include/asm/olpc_ofw.h b/arch/x86/include/asm/olpc_ofw.h
index c5d3a5a..a0e24e7 100644
--- a/arch/x86/include/asm/olpc_ofw.h
+++ b/arch/x86/include/asm/olpc_ofw.h
@@ -26,15 +26,11 @@ extern void setup_olpc_ofw_pgd(void);
 /* check if OFW was detected during boot */
 extern bool olpc_ofw_present(void);
 
+extern void olpc_dt_build_devicetree(void);
+
 #else /* !CONFIG_OLPC */
 static inline void olpc_ofw_detect(void) { }
 static inline void setup_olpc_ofw_pgd(void) { }
 #endif /* !CONFIG_OLPC */
 
-#ifdef CONFIG_OF_PROMTREE
-extern void olpc_dt_build_devicetree(void);
-#else
-static inline void olpc_dt_build_devicetree(void) { }
-#endif
-
 #endif /* _ASM_X86_OLPC_OFW_H */
diff --git a/arch/x86/platform/olpc/Makefile b/arch/x86/platform/olpc/Makefile
index c2a8cab..81c5e21 100644
--- a/arch/x86/platform/olpc/Makefile
+++ b/arch/x86/platform/olpc/Makefile
@@ -1,4 +1,2 @@
-obj-$(CONFIG_OLPC)		+= olpc.o
+obj-$(CONFIG_OLPC)		+= olpc.o olpc_ofw.o olpc_dt.o
 obj-$(CONFIG_OLPC_XO1)		+= olpc-xo1.o
-obj-$(CONFIG_OLPC)		+= olpc_ofw.o
-obj-$(CONFIG_OF_PROMTREE)	+= olpc_dt.o
diff --git a/arch/x86/platform/olpc/olpc.c b/arch/x86/platform/olpc/olpc.c
index edaf3fe..2ecc98d 100644
--- a/arch/x86/platform/olpc/olpc.c
+++ b/arch/x86/platform/olpc/olpc.c
@@ -18,6 +18,7 @@
 #include <linux/io.h>
 #include <linux/string.h>
 #include <linux/platform_device.h>
+#include <linux/of.h>
 
 #include <asm/geode.h>
 #include <asm/setup.h>
@@ -187,41 +188,45 @@ err:
 }
 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 
-static bool __init check_ofw_architecture(void)
+static bool __init check_ofw_architecture(struct device_node *root)
 {
-	size_t propsize;
-	char olpc_arch[5];
-	const void *args[] = { NULL, "architecture", olpc_arch, (void *)5 };
-	void *res[] = { &propsize };
+	const char *olpc_arch;
+	int propsize;
 
-	if (olpc_ofw("getprop", args, res)) {
-		printk(KERN_ERR "ofw: getprop call failed!\n");
-		return false;
-	}
+	olpc_arch = of_get_property(root, "architecture", &propsize);
 	return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
 }
 
-static u32 __init get_board_revision(void)
+static u32 __init get_board_revision(struct device_node *root)
 {
-	size_t propsize;
-	__be32 rev;
-	const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
-	void *res[] = { &propsize };
-
-	if (olpc_ofw("getprop", args, res) || propsize != 4) {
-		printk(KERN_ERR "ofw: getprop call failed!\n");
-		return cpu_to_be32(0);
-	}
-	return be32_to_cpu(rev);
+	int propsize;
+	const __be32 *rev;
+
+	rev = of_get_property(root, "board-revision-int", &propsize);
+	if (propsize != 4)
+		return 0;
+
+	return be32_to_cpu(*rev);
 }
 
 static bool __init platform_detect(void)
 {
-	if (!check_ofw_architecture())
+	struct device_node *root = of_find_node_by_path("/");
+	bool success;
+
+	if (!root)
 		return false;
+
+	success = check_ofw_architecture(root);
+	if (!success)
+		goto out;
+
 	olpc_platform_info.flags |= OLPC_F_PRESENT;
-	olpc_platform_info.boardrev = get_board_revision();
-	return true;
+	olpc_platform_info.boardrev = get_board_revision(root);
+
+out:
+	of_node_put(root);
+	return success;
 }
 
 static int __init add_xo1_platform_devices(void)
diff --git a/arch/x86/platform/olpc/olpc_dt.c b/arch/x86/platform/olpc/olpc_dt.c
index 044bda5..09cbede 100644
--- a/arch/x86/platform/olpc/olpc_dt.c
+++ b/arch/x86/platform/olpc/olpc_dt.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/bootmem.h>
 #include <linux/of.h>
+#include <linux/of_platform.h>
 #include <linux/of_pdt.h>
 #include <asm/olpc_ofw.h>
 
@@ -180,3 +181,17 @@ void __init olpc_dt_build_devicetree(void)
 	pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
 			prom_early_allocated);
 }
+
+/* A list of DT node/bus matches that we want to expose as platform devices */
+static struct of_device_id __initdata of_ids[] = {
+	{ .compatible = "olpc,xo1-battery" },
+	{ .compatible = "olpc,xo1-dcon" },
+	{ .compatible = "olpc,xo1-rtc" },
+	{},
+};
+
+static int __init declare_of_platform_devices(void)
+{
+	return of_platform_bus_probe(NULL, of_ids, NULL);
+}
+device_initcall(declare_of_platform_devices);
-- 
1.7.4

Re: [RFC 1/3] OLPC: Use device tree for platform identification

[Andres Salomon]

The x86 folks should probably be cc'd as well..

Overall, this looks good, just a few minor issues below.

On Fri,  4 Mar 2011 17:12:14 +0000 (GMT)
Daniel Drake <dsd-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org> wrote:

> Make OLPC fully depend on device tree, and use it to identify the OLPC
> platform details. Some nodes are exposed as platform devices where we
> plan to use device tree for device probing.
> 
> Signed-off-by: Daniel Drake <dsd-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org>
> ---
>  arch/x86/Kconfig                 |    2 +-
>  arch/x86/include/asm/olpc_ofw.h  |    8 +----
>  arch/x86/platform/olpc/Makefile  |    4 +--
>  arch/x86/platform/olpc/olpc.c    |   51
> ++++++++++++++++++++-----------------
> arch/x86/platform/olpc/olpc_dt.c |   15 +++++++++++ 5 files changed,
> 47 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index b4c2e9c..471221b 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2071,7 +2071,7 @@ config OLPC
>  	depends on !X86_PAE
>  	select GPIOLIB
>  	select OF
> -	select OF_PROMTREE if PROC_DEVICETREE
> +	select OF_PROMTREE
>  	---help---
>  	  Add support for detecting the unique features of the OLPC
>  	  XO hardware.
> diff --git a/arch/x86/include/asm/olpc_ofw.h
> b/arch/x86/include/asm/olpc_ofw.h index c5d3a5a..a0e24e7 100644
> --- a/arch/x86/include/asm/olpc_ofw.h
> +++ b/arch/x86/include/asm/olpc_ofw.h
> @@ -26,15 +26,11 @@ extern void setup_olpc_ofw_pgd(void);
>  /* check if OFW was detected during boot */
>  extern bool olpc_ofw_present(void);
>  
> +extern void olpc_dt_build_devicetree(void);
> +
>  #else /* !CONFIG_OLPC */
>  static inline void olpc_ofw_detect(void) { }
>  static inline void setup_olpc_ofw_pgd(void) { }

You need the following here, as build_devicetree is called
from x86's paging_init():

static inline void olpc_dt_build_devicetree(void) { }

>  #endif /* !CONFIG_OLPC */
>  
> -#ifdef CONFIG_OF_PROMTREE
> -extern void olpc_dt_build_devicetree(void);
> -#else
> -static inline void olpc_dt_build_devicetree(void) { }
> -#endif
> -
>  #endif /* _ASM_X86_OLPC_OFW_H */
> diff --git a/arch/x86/platform/olpc/Makefile
> b/arch/x86/platform/olpc/Makefile index c2a8cab..81c5e21 100644
> --- a/arch/x86/platform/olpc/Makefile
> +++ b/arch/x86/platform/olpc/Makefile
> @@ -1,4 +1,2 @@
> -obj-$(CONFIG_OLPC)		+= olpc.o
> +obj-$(CONFIG_OLPC)		+= olpc.o olpc_ofw.o olpc_dt.o
>  obj-$(CONFIG_OLPC_XO1)		+= olpc-xo1.o
> -obj-$(CONFIG_OLPC)		+= olpc_ofw.o
> -obj-$(CONFIG_OF_PROMTREE)	+= olpc_dt.o
> diff --git a/arch/x86/platform/olpc/olpc.c
> b/arch/x86/platform/olpc/olpc.c index edaf3fe..2ecc98d 100644
> --- a/arch/x86/platform/olpc/olpc.c
> +++ b/arch/x86/platform/olpc/olpc.c
> @@ -18,6 +18,7 @@
>  #include <linux/io.h>
>  #include <linux/string.h>
>  #include <linux/platform_device.h>
> +#include <linux/of.h>
>  
>  #include <asm/geode.h>
>  #include <asm/setup.h>
> @@ -187,41 +188,45 @@ err:
>  }
>  EXPORT_SYMBOL_GPL(olpc_ec_cmd);
>  
> -static bool __init check_ofw_architecture(void)
> +static bool __init check_ofw_architecture(struct device_node *root)
>  {
> -	size_t propsize;
> -	char olpc_arch[5];
> -	const void *args[] = { NULL, "architecture", olpc_arch,
> (void *)5 };
> -	void *res[] = { &propsize };
> +	const char *olpc_arch;
> +	int propsize;
>  
> -	if (olpc_ofw("getprop", args, res)) {
> -		printk(KERN_ERR "ofw: getprop call failed!\n");
> -		return false;
> -	}
> +	olpc_arch = of_get_property(root, "architecture", &propsize);
>  	return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
>  }
>  
> -static u32 __init get_board_revision(void)
> +static u32 __init get_board_revision(struct device_node *root)
>  {
> -	size_t propsize;
> -	__be32 rev;
> -	const void *args[] = { NULL, "board-revision-int", &rev,
> (void *)4 };
> -	void *res[] = { &propsize };
> -
> -	if (olpc_ofw("getprop", args, res) || propsize != 4) {
> -		printk(KERN_ERR "ofw: getprop call failed!\n");
> -		return cpu_to_be32(0);
> -	}
> -	return be32_to_cpu(rev);
> +	int propsize;
> +	const __be32 *rev;
> +
> +	rev = of_get_property(root, "board-revision-int", &propsize);
> +	if (propsize != 4)
> +		return 0;
> +
> +	return be32_to_cpu(*rev);
>  }
>  
>  static bool __init platform_detect(void)
>  {
> -	if (!check_ofw_architecture())
> +	struct device_node *root = of_find_node_by_path("/");
> +	bool success;
> +
> +	if (!root)
>  		return false;
> +
> +	success = check_ofw_architecture(root);
> +	if (!success)
> +		goto out;
> +
>  	olpc_platform_info.flags |= OLPC_F_PRESENT;
> -	olpc_platform_info.boardrev = get_board_revision();
> -	return true;
> +	olpc_platform_info.boardrev = get_board_revision(root);
> +
> +out:
> +	of_node_put(root);
> +	return success;


Actually, rather than the goto, this could be

success = check_ofw_architecture
if (success)
	olpc_platform_info.boardrev = get_board_revision(root);
of_node_put(root);
return success;

>  }
>  
>  static int __init add_xo1_platform_devices(void)
> diff --git a/arch/x86/platform/olpc/olpc_dt.c
> b/arch/x86/platform/olpc/olpc_dt.c index 044bda5..09cbede 100644
> --- a/arch/x86/platform/olpc/olpc_dt.c
> +++ b/arch/x86/platform/olpc/olpc_dt.c
> @@ -19,6 +19,7 @@
>  #include <linux/kernel.h>
>  #include <linux/bootmem.h>
>  #include <linux/of.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_pdt.h>
>  #include <asm/olpc_ofw.h>
>  
> @@ -180,3 +181,17 @@ void __init olpc_dt_build_devicetree(void)
>  	pr_info("PROM DT: Built device tree with %u bytes of
> memory.\n", prom_early_allocated);
>  }
> +
> +/* A list of DT node/bus matches that we want to expose as platform
> devices */ +static struct of_device_id __initdata of_ids[] = {
> +	{ .compatible = "olpc,xo1-battery" },
> +	{ .compatible = "olpc,xo1-dcon" },
> +	{ .compatible = "olpc,xo1-rtc" },
> +	{},
> +};
> +
> +static int __init declare_of_platform_devices(void)
> +{
> +	return of_platform_bus_probe(NULL, of_ids, NULL);
> +}
> +device_initcall(declare_of_platform_devices);

How about 'olpc_create_platform_devices' or some such name?  That's
what's really happening here, right?

Re: [RFC 1/3] OLPC: Use device tree for platform identification

[Daniel Drake]

On 4 March 2011 18:01, Andres Salomon <dilinger-pFFUokh25LWsTnJN9+BGXg@public.gmane.org> wrote:
>> +static int __init declare_of_platform_devices(void)
>> +{
>> +     return of_platform_bus_probe(NULL, of_ids, NULL);
>> +}
>> +device_initcall(declare_of_platform_devices);
>
> How about 'olpc_create_platform_devices' or some such name?  That's
> what's really happening here, right?

The reason I called it declare_of_platform_devices is because thats
what all the other platforms do (do a git grep). do you still think it
should be renamed?

Daniel

Re: [RFC 1/3] OLPC: Use device tree for platform identification

[Andres Salomon]

On Tue, 8 Mar 2011 21:13:00 +0000
Daniel Drake <dsd@laptop.org> wrote:

> On 4 March 2011 18:01, Andres Salomon <dilinger@queued.net> wrote:
> >> +static int __init declare_of_platform_devices(void)
> >> +{
> >> +     return of_platform_bus_probe(NULL, of_ids, NULL);
> >> +}
> >> +device_initcall(declare_of_platform_devices);
> >
> > How about 'olpc_create_platform_devices' or some such name?  That's
> > what's really happening here, right?
> 
> The reason I called it declare_of_platform_devices is because thats
> what all the other platforms do (do a git grep). do you still think it
> should be renamed?
> 

Yes, unless there's some reason why it should be named "declare".  I'm
assuming the names used in ppc platform device code are like that for
historical reasons?

_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [RFC 1/3] OLPC: Use device tree for platform identification

[Grant Likely]

On Tue, Mar 08, 2011 at 07:35:46PM -0800, Andres Salomon wrote:
> On Tue, 8 Mar 2011 21:13:00 +0000
> Daniel Drake <dsd-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org> wrote:
> 
> > On 4 March 2011 18:01, Andres Salomon <dilinger-pFFUokh25LWsTnJN9+BGXg@public.gmane.org> wrote:
> > >> +static int __init declare_of_platform_devices(void)
> > >> +{
> > >> +     return of_platform_bus_probe(NULL, of_ids, NULL);
> > >> +}
> > >> +device_initcall(declare_of_platform_devices);
> > >
> > > How about 'olpc_create_platform_devices' or some such name?  That's
> > > what's really happening here, right?
> > 
> > The reason I called it declare_of_platform_devices is because thats
> > what all the other platforms do (do a git grep). do you still think it
> > should be renamed?
> > 
> 
> Yes, unless there's some reason why it should be named "declare".  I'm
> assuming the names used in ppc platform device code are like that for
> historical reasons?

Probably, but they probably aren't very good reasons.  Name it what
makes sense for OLPC.  An olpc_ prefix certainly makes sense to me.

BTW, using a device_initcall() isn't very multiplatform friendly.  It
will get called regardless of the machine that the kernel is booted on
(OLPC or no) which probably isn't what you want.

g.

Re: [RFC 1/3] OLPC: Use device tree for platform identification

[Grant Likely]

On Fri, Mar 04, 2011 at 05:12:14PM +0000, Daniel Drake wrote:
> Make OLPC fully depend on device tree, and use it to identify the OLPC
> platform details. Some nodes are exposed as platform devices where we
> plan to use device tree for device probing.
> 
> Signed-off-by: Daniel Drake <dsd-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org>

Looks good to me.

g.

> ---
>  arch/x86/Kconfig                 |    2 +-
>  arch/x86/include/asm/olpc_ofw.h  |    8 +----
>  arch/x86/platform/olpc/Makefile  |    4 +--
>  arch/x86/platform/olpc/olpc.c    |   51 ++++++++++++++++++++-----------------
>  arch/x86/platform/olpc/olpc_dt.c |   15 +++++++++++
>  5 files changed, 47 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index b4c2e9c..471221b 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2071,7 +2071,7 @@ config OLPC
>  	depends on !X86_PAE
>  	select GPIOLIB
>  	select OF
> -	select OF_PROMTREE if PROC_DEVICETREE
> +	select OF_PROMTREE
>  	---help---
>  	  Add support for detecting the unique features of the OLPC
>  	  XO hardware.
> diff --git a/arch/x86/include/asm/olpc_ofw.h b/arch/x86/include/asm/olpc_ofw.h
> index c5d3a5a..a0e24e7 100644
> --- a/arch/x86/include/asm/olpc_ofw.h
> +++ b/arch/x86/include/asm/olpc_ofw.h
> @@ -26,15 +26,11 @@ extern void setup_olpc_ofw_pgd(void);
>  /* check if OFW was detected during boot */
>  extern bool olpc_ofw_present(void);
>  
> +extern void olpc_dt_build_devicetree(void);
> +
>  #else /* !CONFIG_OLPC */
>  static inline void olpc_ofw_detect(void) { }
>  static inline void setup_olpc_ofw_pgd(void) { }
>  #endif /* !CONFIG_OLPC */
>  
> -#ifdef CONFIG_OF_PROMTREE
> -extern void olpc_dt_build_devicetree(void);
> -#else
> -static inline void olpc_dt_build_devicetree(void) { }
> -#endif
> -
>  #endif /* _ASM_X86_OLPC_OFW_H */
> diff --git a/arch/x86/platform/olpc/Makefile b/arch/x86/platform/olpc/Makefile
> index c2a8cab..81c5e21 100644
> --- a/arch/x86/platform/olpc/Makefile
> +++ b/arch/x86/platform/olpc/Makefile
> @@ -1,4 +1,2 @@
> -obj-$(CONFIG_OLPC)		+= olpc.o
> +obj-$(CONFIG_OLPC)		+= olpc.o olpc_ofw.o olpc_dt.o
>  obj-$(CONFIG_OLPC_XO1)		+= olpc-xo1.o
> -obj-$(CONFIG_OLPC)		+= olpc_ofw.o
> -obj-$(CONFIG_OF_PROMTREE)	+= olpc_dt.o
> diff --git a/arch/x86/platform/olpc/olpc.c b/arch/x86/platform/olpc/olpc.c
> index edaf3fe..2ecc98d 100644
> --- a/arch/x86/platform/olpc/olpc.c
> +++ b/arch/x86/platform/olpc/olpc.c
> @@ -18,6 +18,7 @@
>  #include <linux/io.h>
>  #include <linux/string.h>
>  #include <linux/platform_device.h>
> +#include <linux/of.h>
>  
>  #include <asm/geode.h>
>  #include <asm/setup.h>
> @@ -187,41 +188,45 @@ err:
>  }
>  EXPORT_SYMBOL_GPL(olpc_ec_cmd);
>  
> -static bool __init check_ofw_architecture(void)
> +static bool __init check_ofw_architecture(struct device_node *root)
>  {
> -	size_t propsize;
> -	char olpc_arch[5];
> -	const void *args[] = { NULL, "architecture", olpc_arch, (void *)5 };
> -	void *res[] = { &propsize };
> +	const char *olpc_arch;
> +	int propsize;
>  
> -	if (olpc_ofw("getprop", args, res)) {
> -		printk(KERN_ERR "ofw: getprop call failed!\n");
> -		return false;
> -	}
> +	olpc_arch = of_get_property(root, "architecture", &propsize);
>  	return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
>  }
>  
> -static u32 __init get_board_revision(void)
> +static u32 __init get_board_revision(struct device_node *root)
>  {
> -	size_t propsize;
> -	__be32 rev;
> -	const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
> -	void *res[] = { &propsize };
> -
> -	if (olpc_ofw("getprop", args, res) || propsize != 4) {
> -		printk(KERN_ERR "ofw: getprop call failed!\n");
> -		return cpu_to_be32(0);
> -	}
> -	return be32_to_cpu(rev);
> +	int propsize;
> +	const __be32 *rev;
> +
> +	rev = of_get_property(root, "board-revision-int", &propsize);
> +	if (propsize != 4)
> +		return 0;
> +
> +	return be32_to_cpu(*rev);
>  }
>  
>  static bool __init platform_detect(void)
>  {
> -	if (!check_ofw_architecture())
> +	struct device_node *root = of_find_node_by_path("/");
> +	bool success;
> +
> +	if (!root)
>  		return false;
> +
> +	success = check_ofw_architecture(root);
> +	if (!success)
> +		goto out;
> +
>  	olpc_platform_info.flags |= OLPC_F_PRESENT;
> -	olpc_platform_info.boardrev = get_board_revision();
> -	return true;
> +	olpc_platform_info.boardrev = get_board_revision(root);
> +
> +out:
> +	of_node_put(root);
> +	return success;
>  }
>  
>  static int __init add_xo1_platform_devices(void)
> diff --git a/arch/x86/platform/olpc/olpc_dt.c b/arch/x86/platform/olpc/olpc_dt.c
> index 044bda5..09cbede 100644
> --- a/arch/x86/platform/olpc/olpc_dt.c
> +++ b/arch/x86/platform/olpc/olpc_dt.c
> @@ -19,6 +19,7 @@
>  #include <linux/kernel.h>
>  #include <linux/bootmem.h>
>  #include <linux/of.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_pdt.h>
>  #include <asm/olpc_ofw.h>
>  
> @@ -180,3 +181,17 @@ void __init olpc_dt_build_devicetree(void)
>  	pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
>  			prom_early_allocated);
>  }
> +
> +/* A list of DT node/bus matches that we want to expose as platform devices */
> +static struct of_device_id __initdata of_ids[] = {
> +	{ .compatible = "olpc,xo1-battery" },
> +	{ .compatible = "olpc,xo1-dcon" },
> +	{ .compatible = "olpc,xo1-rtc" },
> +	{},
> +};
> +
> +static int __init declare_of_platform_devices(void)
> +{
> +	return of_platform_bus_probe(NULL, of_ids, NULL);
> +}
> +device_initcall(declare_of_platform_devices);
> -- 
> 1.7.4
>