[PATCH 0/2] Rework OF i2c support code

[PATCH 0/2] Rework OF i2c support code

[Grant Likely]

The following series reworks the of_i2c support code so that i2c drivers
can be matched to devices using the struct device_driver of_match table,
and so that i2c devices described in a device tree node will be
transparently registered if the i2c adapter of_node pointer is set.

The OF hooks used in the second patch are entirely compiled out when
CONFIG_OF is not set.

---

Ben, these changes probably should go through my devicetree branch.  They
are currently sitting in the following branch, and I'll move it over to
next-devicetree in a week or so if I don't receive any objections (it
can always come out again if there are, but I want the test coverage).

git://git.secretlab.ca/git/linux-2.6 test-devicetree

Grant Likely (2):
      of/i2c: Generalize OF support
      i2c: Add OF-style registration and binding


 drivers/i2c/busses/i2c-cpm.c     |    6 +----
 drivers/i2c/busses/i2c-ibm_iic.c |    4 +--
 drivers/i2c/busses/i2c-mpc.c     |    2 +-
 drivers/i2c/i2c-core.c           |    9 ++++++++
 drivers/of/Kconfig               |    2 +-
 drivers/of/of_i2c.c              |   44 ++++++++++++++++++++++++--------------
 include/linux/of_i2c.h           |   13 +++++++++--
 7 files changed, 51 insertions(+), 29 deletions(-)

[PATCH 1/2] of/i2c: Generalize OF support

[Grant Likely]

This patch cleans up the i2c OF support code to make it selectable by
all architectures and allow for automatic registration of i2c devices.

Signed-off-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
---
 drivers/i2c/busses/i2c-cpm.c     |    3 ++-
 drivers/i2c/busses/i2c-ibm_iic.c |    3 ++-
 drivers/i2c/busses/i2c-mpc.c     |    3 ++-
 drivers/of/Kconfig               |    2 +-
 drivers/of/of_i2c.c              |   44 ++++++++++++++++++++++++--------------
 include/linux/of_i2c.h           |   13 +++++++++--
 6 files changed, 45 insertions(+), 23 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index b02b453..03ae62e 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -652,6 +652,7 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
 	cpm->adap = cpm_ops;
 	i2c_set_adapdata(&cpm->adap, cpm);
 	cpm->adap.dev.parent = &ofdev->dev;
+	cpm->adap.dev.of_node = of_node_get(ofdev->dev.of_node);
 
 	result = cpm_i2c_setup(cpm);
 	if (result) {
@@ -679,7 +680,7 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
 	/*
 	 * register OF I2C devices
 	 */
-	of_register_i2c_devices(&cpm->adap, ofdev->dev.of_node);
+	of_i2c_register_devices(&cpm->adap);
 
 	return 0;
 out_shut:
diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
index bf34413..d964121 100644
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -745,6 +745,7 @@ static int __devinit iic_probe(struct of_device *ofdev,
 	/* Register it with i2c layer */
 	adap = &dev->adap;
 	adap->dev.parent = &ofdev->dev;
+	adap->dev.of_node = of_node_get(np);
 	strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
 	i2c_set_adapdata(adap, dev);
 	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
@@ -761,7 +762,7 @@ static int __devinit iic_probe(struct of_device *ofdev,
 		 dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
 
 	/* Now register all the child nodes */
-	of_register_i2c_devices(adap, np);
+	of_i2c_register_devices(adap);
 
 	return 0;
 
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index df00eb1..d2e26d2 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -600,13 +600,14 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
 	i2c->adap = mpc_ops;
 	i2c_set_adapdata(&i2c->adap, i2c);
 	i2c->adap.dev.parent = &op->dev;
+	i2c->adap.dev.of_node = of_node_get(op->dev.of_node);
 
 	result = i2c_add_adapter(&i2c->adap);
 	if (result < 0) {
 		dev_err(i2c->dev, "failed to add adapter\n");
 		goto fail_add;
 	}
-	of_register_i2c_devices(&i2c->adap, op->dev.of_node);
+	of_i2c_register_devices(&i2c->adap);
 
 	return result;
 
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 097f42a..80dd631 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -26,7 +26,7 @@ config OF_GPIO
 
 config OF_I2C
 	def_tristate I2C
-	depends on (PPC_OF || MICROBLAZE) && I2C
+	depends on OF && !SPARC && I2C
 	help
 	  OpenFirmware I2C accessors
 
diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index ab6522c..e05f9a1 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -14,34 +14,49 @@
 #include <linux/i2c.h>
 #include <linux/of.h>
 #include <linux/of_i2c.h>
+#include <linux/of_irq.h>
 #include <linux/module.h>
 
-void of_register_i2c_devices(struct i2c_adapter *adap,
-			     struct device_node *adap_node)
+void of_i2c_register_devices(struct i2c_adapter *adap)
 {
 	void *result;
 	struct device_node *node;
 
-	for_each_child_of_node(adap_node, node) {
+	/* Only register child devices if the adapter has a node pointer set */
+	if (!adap->dev.of_node)
+		return;
+
+	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
+
+	for_each_child_of_node(adap->dev.of_node, node) {
 		struct i2c_board_info info = {};
 		struct dev_archdata dev_ad = {};
 		const __be32 *addr;
 		int len;
 
-		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0)
+		dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
+
+		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
+			dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
+				node->full_name);
 			continue;
+		}
 
 		addr = of_get_property(node, "reg", &len);
-		if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
-			printk(KERN_ERR
-			       "of-i2c: invalid i2c device entry\n");
+		if (!addr || (len < sizeof(int))) {
+			dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
+				node->full_name);
 			continue;
 		}
 
-		info.irq = irq_of_parse_and_map(node, 0);
-
 		info.addr = be32_to_cpup(addr);
+		if (info.addr > (1 << 10) - 1) {
+			dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
+				info.addr, node->full_name);
+			continue;
+		}
 
+		info.irq = irq_of_parse_and_map(node, 0);
 		info.of_node = node;
 		info.archdata = &dev_ad;
 
@@ -49,10 +64,8 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
 
 		result = i2c_new_device(adap, &info);
 		if (result == NULL) {
-			printk(KERN_ERR
-			       "of-i2c: Failed to load driver for %s\n",
-			       info.type);
-			irq_dispose_mapping(info.irq);
+			dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
+			        node->full_name);
 			continue;
 		}
 
@@ -64,7 +77,7 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
 		of_node_get(node);
 	}
 }
-EXPORT_SYMBOL(of_register_i2c_devices);
+EXPORT_SYMBOL(of_i2c_register_devices);
 
 static int of_dev_node_match(struct device *dev, void *data)
 {
@@ -76,8 +89,7 @@ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 {
 	struct device *dev;
 
-	dev = bus_find_device(&i2c_bus_type, NULL, node,
-					 of_dev_node_match);
+	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 	if (!dev)
 		return NULL;
 
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
index 34974b5..0efe8d4 100644
--- a/include/linux/of_i2c.h
+++ b/include/linux/of_i2c.h
@@ -12,12 +12,19 @@
 #ifndef __LINUX_OF_I2C_H
 #define __LINUX_OF_I2C_H
 
+#if defined(CONFIG_OF_I2C) || defined(CONFIG_OF_I2C_MODULE)
 #include <linux/i2c.h>
 
-void of_register_i2c_devices(struct i2c_adapter *adap,
-			     struct device_node *adap_node);
+extern void of_i2c_register_devices(struct i2c_adapter *adap);
 
 /* must call put_device() when done with returned i2c_client device */
-struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
+extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
+
+#else
+static inline void of_i2c_register_devices(struct i2c_adapter *adap)
+{
+	return;
+}
+#endif /* CONFIG_OF_I2C */
 
 #endif /* __LINUX_OF_I2C_H */

Re: [PATCH 1/2] of/i2c: Generalize OF support

[Wolfram Sang]

[-- Attachment #1.1: Type: text/plain, Size: 7908 bytes --]

Hi Grant,

looks good to me in general. A few questions:

On Wed, Jun 09, 2010 at 11:22:32PM -0600, Grant Likely wrote:
> This patch cleans up the i2c OF support code to make it selectable by
> all architectures and allow for automatic registration of i2c devices.
> 
> Signed-off-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
> ---
>  drivers/i2c/busses/i2c-cpm.c     |    3 ++-
>  drivers/i2c/busses/i2c-ibm_iic.c |    3 ++-
>  drivers/i2c/busses/i2c-mpc.c     |    3 ++-
>  drivers/of/Kconfig               |    2 +-
>  drivers/of/of_i2c.c              |   44 ++++++++++++++++++++++++--------------
>  include/linux/of_i2c.h           |   13 +++++++++--
>  6 files changed, 45 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
> index b02b453..03ae62e 100644
> --- a/drivers/i2c/busses/i2c-cpm.c
> +++ b/drivers/i2c/busses/i2c-cpm.c
> @@ -652,6 +652,7 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
>  	cpm->adap = cpm_ops;
>  	i2c_set_adapdata(&cpm->adap, cpm);
>  	cpm->adap.dev.parent = &ofdev->dev;
> +	cpm->adap.dev.of_node = of_node_get(ofdev->dev.of_node);
>  
>  	result = cpm_i2c_setup(cpm);
>  	if (result) {
> @@ -679,7 +680,7 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
>  	/*
>  	 * register OF I2C devices
>  	 */
> -	of_register_i2c_devices(&cpm->adap, ofdev->dev.of_node);
> +	of_i2c_register_devices(&cpm->adap);
>  
>  	return 0;
>  out_shut:
> diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
> index bf34413..d964121 100644
> --- a/drivers/i2c/busses/i2c-ibm_iic.c
> +++ b/drivers/i2c/busses/i2c-ibm_iic.c
> @@ -745,6 +745,7 @@ static int __devinit iic_probe(struct of_device *ofdev,
>  	/* Register it with i2c layer */
>  	adap = &dev->adap;
>  	adap->dev.parent = &ofdev->dev;
> +	adap->dev.of_node = of_node_get(np);
>  	strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
>  	i2c_set_adapdata(adap, dev);
>  	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
> @@ -761,7 +762,7 @@ static int __devinit iic_probe(struct of_device *ofdev,
>  		 dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
>  
>  	/* Now register all the child nodes */
> -	of_register_i2c_devices(adap, np);
> +	of_i2c_register_devices(adap);
>  
>  	return 0;
>  
> diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
> index df00eb1..d2e26d2 100644
> --- a/drivers/i2c/busses/i2c-mpc.c
> +++ b/drivers/i2c/busses/i2c-mpc.c
> @@ -600,13 +600,14 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
>  	i2c->adap = mpc_ops;
>  	i2c_set_adapdata(&i2c->adap, i2c);
>  	i2c->adap.dev.parent = &op->dev;
> +	i2c->adap.dev.of_node = of_node_get(op->dev.of_node);
>  
>  	result = i2c_add_adapter(&i2c->adap);
>  	if (result < 0) {
>  		dev_err(i2c->dev, "failed to add adapter\n");
>  		goto fail_add;
>  	}
> -	of_register_i2c_devices(&i2c->adap, op->dev.of_node);
> +	of_i2c_register_devices(&i2c->adap);
>  
>  	return result;
>  
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index 097f42a..80dd631 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -26,7 +26,7 @@ config OF_GPIO
>  
>  config OF_I2C
>  	def_tristate I2C
> -	depends on (PPC_OF || MICROBLAZE) && I2C
> +	depends on OF && !SPARC && I2C
>  	help
>  	  OpenFirmware I2C accessors
>  
> diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
> index ab6522c..e05f9a1 100644
> --- a/drivers/of/of_i2c.c
> +++ b/drivers/of/of_i2c.c
> @@ -14,34 +14,49 @@
>  #include <linux/i2c.h>
>  #include <linux/of.h>
>  #include <linux/of_i2c.h>
> +#include <linux/of_irq.h>
>  #include <linux/module.h>
>  
> -void of_register_i2c_devices(struct i2c_adapter *adap,
> -			     struct device_node *adap_node)
> +void of_i2c_register_devices(struct i2c_adapter *adap)
>  {
>  	void *result;
>  	struct device_node *node;
>  
> -	for_each_child_of_node(adap_node, node) {
> +	/* Only register child devices if the adapter has a node pointer set */
> +	if (!adap->dev.of_node)
> +		return;
> +
> +	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
> +
> +	for_each_child_of_node(adap->dev.of_node, node) {
>  		struct i2c_board_info info = {};
>  		struct dev_archdata dev_ad = {};
>  		const __be32 *addr;
>  		int len;
>  
> -		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0)
> +		dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
> +
> +		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
> +			dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
> +				node->full_name);
>  			continue;
> +		}
>  
>  		addr = of_get_property(node, "reg", &len);
> -		if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
> -			printk(KERN_ERR
> -			       "of-i2c: invalid i2c device entry\n");
> +		if (!addr || (len < sizeof(int))) {
> +			dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
> +				node->full_name);
>  			continue;
>  		}
>  
> -		info.irq = irq_of_parse_and_map(node, 0);
> -
>  		info.addr = be32_to_cpup(addr);
> +		if (info.addr > (1 << 10) - 1) {
> +			dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
> +				info.addr, node->full_name);
> +			continue;
> +		}
>  
> +		info.irq = irq_of_parse_and_map(node, 0);
>  		info.of_node = node;
>  		info.archdata = &dev_ad;
>  
> @@ -49,10 +64,8 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>  
>  		result = i2c_new_device(adap, &info);
>  		if (result == NULL) {
> -			printk(KERN_ERR
> -			       "of-i2c: Failed to load driver for %s\n",
> -			       info.type);
> -			irq_dispose_mapping(info.irq);

Why is the dispose removed?

> +			dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
> +			        node->full_name);
>  			continue;
>  		}
>  
> @@ -64,7 +77,7 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>  		of_node_get(node);
>  	}
>  }
> -EXPORT_SYMBOL(of_register_i2c_devices);
> +EXPORT_SYMBOL(of_i2c_register_devices);
>  
>  static int of_dev_node_match(struct device *dev, void *data)
>  {
> @@ -76,8 +89,7 @@ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
>  {
>  	struct device *dev;
>  
> -	dev = bus_find_device(&i2c_bus_type, NULL, node,
> -					 of_dev_node_match);
> +	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);

This change looks unrelated to me; where was this changed?

>  	if (!dev)
>  		return NULL;
>  
> diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
> index 34974b5..0efe8d4 100644
> --- a/include/linux/of_i2c.h
> +++ b/include/linux/of_i2c.h
> @@ -12,12 +12,19 @@
>  #ifndef __LINUX_OF_I2C_H
>  #define __LINUX_OF_I2C_H
>  
> +#if defined(CONFIG_OF_I2C) || defined(CONFIG_OF_I2C_MODULE)
>  #include <linux/i2c.h>
>  
> -void of_register_i2c_devices(struct i2c_adapter *adap,
> -			     struct device_node *adap_node);
> +extern void of_i2c_register_devices(struct i2c_adapter *adap);
>  
>  /* must call put_device() when done with returned i2c_client device */
> -struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
> +extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
> +
> +#else
> +static inline void of_i2c_register_devices(struct i2c_adapter *adap)
> +{
> +	return;
> +}
> +#endif /* CONFIG_OF_I2C */
>  
>  #endif /* __LINUX_OF_I2C_H */
> 
> --
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-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH 1/2] of/i2c: Generalize OF support

[Grant Likely]

On Thu, Jun 10, 2010 at 3:52 AM, Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:
> Hi Grant,
>
> looks good to me in general. A few questions:
>
> On Wed, Jun 09, 2010 at 11:22:32PM -0600, Grant Likely wrote:
>> This patch cleans up the i2c OF support code to make it selectable by
>> all architectures and allow for automatic registration of i2c devices.
>>
>> Signed-off-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
>> ---
>>  drivers/i2c/busses/i2c-cpm.c     |    3 ++-
>>  drivers/i2c/busses/i2c-ibm_iic.c |    3 ++-
>>  drivers/i2c/busses/i2c-mpc.c     |    3 ++-
>>  drivers/of/Kconfig               |    2 +-
>>  drivers/of/of_i2c.c              |   44 ++++++++++++++++++++++++--------------
>>  include/linux/of_i2c.h           |   13 +++++++++--
>>  6 files changed, 45 insertions(+), 23 deletions(-)
>>

Hi Wolfram, thanks for the review.  Replies below.

>> @@ -49,10 +64,8 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>>
>>               result = i2c_new_device(adap, &info);
>>               if (result == NULL) {
>> -                     printk(KERN_ERR
>> -                            "of-i2c: Failed to load driver for %s\n",
>> -                            info.type);
>> -                     irq_dispose_mapping(info.irq);
>
> Why is the dispose removed?

Hmmm... That looks like a mistake.  I'll add it back.

>
>> +                     dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
>> +                             node->full_name);
>>                       continue;
>>               }
>>
>> @@ -64,7 +77,7 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>>               of_node_get(node);
>>       }
>>  }
>> -EXPORT_SYMBOL(of_register_i2c_devices);
>> +EXPORT_SYMBOL(of_i2c_register_devices);
>>
>>  static int of_dev_node_match(struct device *dev, void *data)
>>  {
>> @@ -76,8 +89,7 @@ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
>>  {
>>       struct device *dev;
>>
>> -     dev = bus_find_device(&i2c_bus_type, NULL, node,
>> -                                      of_dev_node_match);
>> +     dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
>
> This change looks unrelated to me; where was this changed?

You're right; unrelated whitespace damage.  I'll remove.

g.

[PATCH 2/2] i2c: Add OF-style registration and binding

[Grant Likely]

This patch adds OF hooks to the i2c core so that devices can automatically
be registered based on device tree data.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 drivers/i2c/busses/i2c-cpm.c     |    5 -----
 drivers/i2c/busses/i2c-ibm_iic.c |    3 ---
 drivers/i2c/busses/i2c-mpc.c     |    1 -
 drivers/i2c/i2c-core.c           |    9 +++++++++
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 03ae62e..e591de1 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -677,11 +677,6 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
 	dev_dbg(&ofdev->dev, "hw routines for %s registered.\n",
 		cpm->adap.name);
 
-	/*
-	 * register OF I2C devices
-	 */
-	of_i2c_register_devices(&cpm->adap);
-
 	return 0;
 out_shut:
 	cpm_i2c_shutdown(cpm);
diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
index d964121..1168d61 100644
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -761,9 +761,6 @@ static int __devinit iic_probe(struct of_device *ofdev,
 	dev_info(&ofdev->dev, "using %s mode\n",
 		 dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
 
-	/* Now register all the child nodes */
-	of_i2c_register_devices(adap);
-
 	return 0;
 
 error_cleanup:
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index d2e26d2..9f7fef8 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -607,7 +607,6 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
 		dev_err(i2c->dev, "failed to add adapter\n");
 		goto fail_add;
 	}
-	of_i2c_register_devices(&i2c->adap);
 
 	return result;
 
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 1cca263..5588ac1 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -30,6 +30,8 @@
 #include <linux/init.h>
 #include <linux/idr.h>
 #include <linux/mutex.h>
+#include <linux/of_i2c.h>
+#include <linux/of_device.h>
 #include <linux/completion.h>
 #include <linux/hardirq.h>
 #include <linux/irqflags.h>
@@ -70,6 +72,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
 	if (!client)
 		return 0;
 
+	/* Attempt an OF style match */
+	if (of_driver_match_device(dev, drv))
+		return 1;
+
 	driver = to_i2c_driver(drv);
 	/* match on an id table if there is one */
 	if (driver->id_table)
@@ -790,6 +796,9 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	if (adap->nr < __i2c_first_dynamic_bus_num)
 		i2c_scan_static_board_info(adap);
 
+	/* Register devices from the device tree */
+	of_i2c_register_devices(adap);
+
 	/* Notify drivers */
 	mutex_lock(&core_lock);
 	dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,