[PATCH 1/2] i2c: implement i2c_verify_adapter

[PATCH 1/2] i2c: implement i2c_verify_adapter

[Stephen Warren]

From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

This converts a struct device * to a struct i2c_adapter * while verifying
that the device really is an I2C adapter. Just like i2c_verify_client.

Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/i2c/i2c-core.c |   17 +++++++++++++++++
 include/linux/i2c.h    |    1 +
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index feb7dc3..a6ad32b 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -772,6 +772,23 @@ struct device_type i2c_adapter_type = {
 };
 EXPORT_SYMBOL_GPL(i2c_adapter_type);
 
+/**
+ * i2c_verify_adapter - return parameter as i2c_adapter or NULL
+ * @dev: device, probably from some driver model iterator
+ *
+ * When traversing the driver model tree, perhaps using driver model
+ * iterators like @device_for_each_child(), you can't assume very much
+ * about the nodes you find.  Use this function to avoid oopses caused
+ * by wrongly treating some non-I2C device as an i2c_adapter.
+ */
+struct i2c_adapter *i2c_verify_adapter(struct device *dev)
+{
+	return (dev->type == &i2c_adapter_type)
+			? to_i2c_adapter(dev)
+			: NULL;
+}
+EXPORT_SYMBOL(i2c_verify_adapter);
+
 #ifdef CONFIG_I2C_COMPAT
 static struct class_compat *i2c_adapter_compat_class;
 #endif
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 195d8b3..b66cb60 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -232,6 +232,7 @@ struct i2c_client {
 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
 
 extern struct i2c_client *i2c_verify_client(struct device *dev);
+extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
 
 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
 {
-- 
1.7.0.4

[PATCH 2/2] of/i2c: implement of_find_i2c_adapter_by_node

[Stephen Warren]

From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

This finds the struct i2c_adapter * for a given device tree node. Just
like of_find_i2c_device_by_node.

Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
Note: This series is a dependency for the pinctrl I2C bus mux I will send in a
minute. It'd probably be easiest to merge this through the I2C tree.
It might also be useful to put this patch (and the others I'll send) in
a separate tree so it can be merged into any SoC trees that wish to use
this new feature.

 drivers/of/of_i2c.c    |   14 ++++++++++++++
 include/linux/of_i2c.h |    4 ++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index 0684887..1e173f3 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -94,4 +94,18 @@ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 }
 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 
+/* must call put_device() when done with returned i2c_adapter device */
+struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
+{
+	struct device *dev;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, node,
+					 of_dev_node_match);
+	if (!dev)
+		return NULL;
+
+	return i2c_verify_adapter(dev);
+}
+EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
+
 MODULE_LICENSE("GPL");
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
index 0efe8d4..1cb775f 100644
--- a/include/linux/of_i2c.h
+++ b/include/linux/of_i2c.h
@@ -20,6 +20,10 @@ extern void of_i2c_register_devices(struct i2c_adapter *adap);
 /* must call put_device() when done with returned i2c_client device */
 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 
+/* must call put_device() when done with returned i2c_adapter device */
+extern struct i2c_adapter *of_find_i2c_adapter_by_node(
+						struct device_node *node);
+
 #else
 static inline void of_i2c_register_devices(struct i2c_adapter *adap)
 {
-- 
1.7.0.4

Re: [PATCH 2/2] of/i2c: implement of_find_i2c_adapter_by_node

[Wolfram Sang]

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On Tue, Apr 17, 2012 at 12:43:34PM -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> This finds the struct i2c_adapter * for a given device tree node. Just
> like of_find_i2c_device_by_node.
> 
> Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Applied to my i2c-next. As it is outside of drivers/i2c/ an ack by Grant
or Rob would be nice.

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH 1/2] i2c: implement i2c_verify_adapter

[Jean Delvare]

Hi Stephen,

On Tue, 17 Apr 2012 12:43:33 -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> This converts a struct device * to a struct i2c_adapter * while verifying
> that the device really is an I2C adapter. Just like i2c_verify_client.
> 
> Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/i2c/i2c-core.c |   17 +++++++++++++++++
>  include/linux/i2c.h    |    1 +
>  2 files changed, 18 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index feb7dc3..a6ad32b 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -772,6 +772,23 @@ struct device_type i2c_adapter_type = {
>  };
>  EXPORT_SYMBOL_GPL(i2c_adapter_type);
>  
> +/**
> + * i2c_verify_adapter - return parameter as i2c_adapter or NULL
> + * @dev: device, probably from some driver model iterator
> + *
> + * When traversing the driver model tree, perhaps using driver model
> + * iterators like @device_for_each_child(), you can't assume very much
> + * about the nodes you find.  Use this function to avoid oopses caused
> + * by wrongly treating some non-I2C device as an i2c_adapter.
> + */
> +struct i2c_adapter *i2c_verify_adapter(struct device *dev)
> +{
> +	return (dev->type == &i2c_adapter_type)
> +			? to_i2c_adapter(dev)
> +			: NULL;
> +}
> +EXPORT_SYMBOL(i2c_verify_adapter);
> +
>  #ifdef CONFIG_I2C_COMPAT
>  static struct class_compat *i2c_adapter_compat_class;
>  #endif
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 195d8b3..b66cb60 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -232,6 +232,7 @@ struct i2c_client {
>  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
>  
>  extern struct i2c_client *i2c_verify_client(struct device *dev);
> +extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
>  
>  static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
>  {

I am fine with this patch:

Acked-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>

I can merge it if you want, but if it is easier for you to merge it
through a different tree, this is equally fine with me, just let me
know what you prefer.

-- 
Jean Delvare

Re: [PATCH 1/2] i2c: implement i2c_verify_adapter

[Stephen Warren]

On 04/17/2012 12:49 PM, Jean Delvare wrote:
> Hi Stephen,
> 
> On Tue, 17 Apr 2012 12:43:33 -0600, Stephen Warren wrote:
>> From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>>
>> This converts a struct device * to a struct i2c_adapter * while verifying
>> that the device really is an I2C adapter. Just like i2c_verify_client.
...
> I am fine with this patch:
> 
> Acked-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
> 
> I can merge it if you want, but if it is easier for you to merge it
> through a different tree, this is equally fine with me, just let me
> know what you prefer.

Wolfram, since the other I2C mux changes are going through your tree,
could you please merge this series too; they are a dependency for my
pinctrl-based I2C mux. Thanks!

Re: [PATCH 1/2] i2c: implement i2c_verify_adapter

[Wolfram Sang]

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> Wolfram, since the other I2C mux changes are going through your tree,
> could you please merge this series too; they are a dependency for my
> pinctrl-based I2C mux. Thanks!

Applied to next.

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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