[v2] i2c: core: add device-managed version of i2c_new_dummy

Message ID 8c0a982f-30d5-1124-c871-b040b5bce636@gmail.com
State New
Headers show

Commit Message

Heiner Kallweit Aug. 22, 2017, 5:45 a.m.
i2c_new_dummy is typically called from the probe function of the
driver for the primary i2c client. It requires calls to
i2c_unregister_device in the error path of the probe function and
in the remove function.
This can be simplified by introducing a device-managed version.

Note the changed error case return value type:
i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- added entry to Documentation/driver-model/devres.txt
- extended documentation of new function
- changed return value type to an ERR_PTR in case of error
---
 Documentation/driver-model/devres.txt |  3 +++
 drivers/i2c/i2c-core-base.c           | 39 +++++++++++++++++++++++++++++++++++
 include/linux/i2c.h                   |  3 +++
 3 files changed, 45 insertions(+)

Comments

Peter Rosin Aug. 23, 2017, 12:09 p.m. | #1
On 2017-08-22 07:45, Heiner Kallweit wrote:
> i2c_new_dummy is typically called from the probe function of the
> driver for the primary i2c client. It requires calls to
> i2c_unregister_device in the error path of the probe function and
> in the remove function.
> This can be simplified by introducing a device-managed version.
> 
> Note the changed error case return value type:
> i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Looks good to me, assuming you have some user in the wings...

Reviewed-by: Peter Rosin <peda@axentia.se>

Cheers,
peda

> ---
> v2:
> - added entry to Documentation/driver-model/devres.txt
> - extended documentation of new function
> - changed return value type to an ERR_PTR in case of error
> ---
>  Documentation/driver-model/devres.txt |  3 +++
>  drivers/i2c/i2c-core-base.c           | 39 +++++++++++++++++++++++++++++++++++
>  include/linux/i2c.h                   |  3 +++
>  3 files changed, 45 insertions(+)
> 
> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
> index 30e04f7a..67d59528 100644
> --- a/Documentation/driver-model/devres.txt
> +++ b/Documentation/driver-model/devres.txt
> @@ -258,6 +258,9 @@ GPIO
>    devm_gpio_request_one()
>    devm_gpio_free()
>  
> +I2C
> +  devm_i2c_new_dummy
> +
>  IIO
>    devm_iio_device_alloc()
>    devm_iio_device_free()
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 12822a4b..aac9491c 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -868,6 +868,45 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
>  }
>  EXPORT_SYMBOL_GPL(i2c_new_dummy);
>  
> +static void devm_i2c_release_dummy(struct device *dev, void *res)
> +{
> +	i2c_unregister_device(*(struct i2c_client **)res);
> +}
> +
> +/**
> + * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver
> + * @dev: device the managed resource is bound to
> + * @adapter: the adapter managing the device
> + * @address: seven bit address to be used
> + * Context: can sleep
> + *
> + * This is the device-managed version of i2c_new_dummy.
> + * Note the changed return value type: It returns the new i2c client
> + * or an ERR_PTR in case of an error.
> + */
> +struct i2c_client *devm_i2c_new_dummy(struct device *dev,
> +				      struct i2c_adapter *adapter,
> +				      u16 address)
> +{
> +	struct i2c_client *ret, **dr;
> +
> +	dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
> +	if (!dr)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = i2c_new_dummy(adapter, address);
> +	if (!ret) {
> +		devres_free(dr);
> +		return ERR_PTR(-EBUSY);
> +	}
> +
> +	*dr = ret;
> +	devres_add(dev, dr);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy);
> +
>  /**
>   * i2c_new_secondary_device - Helper to get the instantiated secondary address
>   * and create the associated device
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index d501d395..d0c091e6 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -381,6 +381,9 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
>  extern struct i2c_client *
>  i2c_new_dummy(struct i2c_adapter *adap, u16 address);
>  
> +extern struct i2c_client *
> +devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address);
> +
>  extern struct i2c_client *
>  i2c_new_secondary_device(struct i2c_client *client,
>  				const char *name,
>
Heiner Kallweit Aug. 23, 2017, 7:12 p.m. | #2
Am 23.08.2017 um 14:09 schrieb Peter Rosin:
> On 2017-08-22 07:45, Heiner Kallweit wrote:
>> i2c_new_dummy is typically called from the probe function of the
>> driver for the primary i2c client. It requires calls to
>> i2c_unregister_device in the error path of the probe function and
>> in the remove function.
>> This can be simplified by introducing a device-managed version.
>>
>> Note the changed error case return value type:
>> i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> 
> Looks good to me, assuming you have some user in the wings...
> I will use it in at24 I2C EEPROM driver. Some patches from me are pending
already, switching to devm_i2c_new_dummy will be one of the next.

Thanks, Heiner

> Reviewed-by: Peter Rosin <peda@axentia.se>
> 
> Cheers,
> peda
> 
>> ---
>> v2:
>> - added entry to Documentation/driver-model/devres.txt
>> - extended documentation of new function
>> - changed return value type to an ERR_PTR in case of error
>> ---
>>  Documentation/driver-model/devres.txt |  3 +++
>>  drivers/i2c/i2c-core-base.c           | 39 +++++++++++++++++++++++++++++++++++
>>  include/linux/i2c.h                   |  3 +++
>>  3 files changed, 45 insertions(+)
>>
>> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
>> index 30e04f7a..67d59528 100644
>> --- a/Documentation/driver-model/devres.txt
>> +++ b/Documentation/driver-model/devres.txt
>> @@ -258,6 +258,9 @@ GPIO
>>    devm_gpio_request_one()
>>    devm_gpio_free()
>>  
>> +I2C
>> +  devm_i2c_new_dummy
>> +
>>  IIO
>>    devm_iio_device_alloc()
>>    devm_iio_device_free()
>> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
>> index 12822a4b..aac9491c 100644
>> --- a/drivers/i2c/i2c-core-base.c
>> +++ b/drivers/i2c/i2c-core-base.c
>> @@ -868,6 +868,45 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
>>  }
>>  EXPORT_SYMBOL_GPL(i2c_new_dummy);
>>  
>> +static void devm_i2c_release_dummy(struct device *dev, void *res)
>> +{
>> +	i2c_unregister_device(*(struct i2c_client **)res);
>> +}
>> +
>> +/**
>> + * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver
>> + * @dev: device the managed resource is bound to
>> + * @adapter: the adapter managing the device
>> + * @address: seven bit address to be used
>> + * Context: can sleep
>> + *
>> + * This is the device-managed version of i2c_new_dummy.
>> + * Note the changed return value type: It returns the new i2c client
>> + * or an ERR_PTR in case of an error.
>> + */
>> +struct i2c_client *devm_i2c_new_dummy(struct device *dev,
>> +				      struct i2c_adapter *adapter,
>> +				      u16 address)
>> +{
>> +	struct i2c_client *ret, **dr;
>> +
>> +	dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
>> +	if (!dr)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	ret = i2c_new_dummy(adapter, address);
>> +	if (!ret) {
>> +		devres_free(dr);
>> +		return ERR_PTR(-EBUSY);
>> +	}
>> +
>> +	*dr = ret;
>> +	devres_add(dev, dr);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy);
>> +
>>  /**
>>   * i2c_new_secondary_device - Helper to get the instantiated secondary address
>>   * and create the associated device
>> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
>> index d501d395..d0c091e6 100644
>> --- a/include/linux/i2c.h
>> +++ b/include/linux/i2c.h
>> @@ -381,6 +381,9 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
>>  extern struct i2c_client *
>>  i2c_new_dummy(struct i2c_adapter *adap, u16 address);
>>  
>> +extern struct i2c_client *
>> +devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address);
>> +
>>  extern struct i2c_client *
>>  i2c_new_secondary_device(struct i2c_client *client,
>>  				const char *name,
>>
> 
>

Patch

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 30e04f7a..67d59528 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -258,6 +258,9 @@  GPIO
   devm_gpio_request_one()
   devm_gpio_free()
 
+I2C
+  devm_i2c_new_dummy
+
 IIO
   devm_iio_device_alloc()
   devm_iio_device_free()
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 12822a4b..aac9491c 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -868,6 +868,45 @@  struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 }
 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 
+static void devm_i2c_release_dummy(struct device *dev, void *res)
+{
+	i2c_unregister_device(*(struct i2c_client **)res);
+}
+
+/**
+ * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver
+ * @dev: device the managed resource is bound to
+ * @adapter: the adapter managing the device
+ * @address: seven bit address to be used
+ * Context: can sleep
+ *
+ * This is the device-managed version of i2c_new_dummy.
+ * Note the changed return value type: It returns the new i2c client
+ * or an ERR_PTR in case of an error.
+ */
+struct i2c_client *devm_i2c_new_dummy(struct device *dev,
+				      struct i2c_adapter *adapter,
+				      u16 address)
+{
+	struct i2c_client *ret, **dr;
+
+	dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return ERR_PTR(-ENOMEM);
+
+	ret = i2c_new_dummy(adapter, address);
+	if (!ret) {
+		devres_free(dr);
+		return ERR_PTR(-EBUSY);
+	}
+
+	*dr = ret;
+	devres_add(dev, dr);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_i2c_new_dummy);
+
 /**
  * i2c_new_secondary_device - Helper to get the instantiated secondary address
  * and create the associated device
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index d501d395..d0c091e6 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -381,6 +381,9 @@  extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
 extern struct i2c_client *
 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 
+extern struct i2c_client *
+devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address);
+
 extern struct i2c_client *
 i2c_new_secondary_device(struct i2c_client *client,
 				const char *name,