[15/18] i2c: i2c-core-acpi: Add i2c_acpi_dev_name()

Message ID 20201130133129.1024662-16-djrscally@gmail.com
State New
Headers show
Series
  • Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows
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Commit Message

Daniel Scally Nov. 30, 2020, 1:31 p.m.
Some places in the kernel allow users to map resources to a device
using device name (for example, gpiod_lookup_table). Currently
this involves waiting for the i2c_client to have been registered so we
can use dev_name(&client->dev). Adding this function means that we can
achieve the same thing without having to wait to the i2c device.

Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes since RFC v3:

	- Patch introduced

 drivers/i2c/i2c-core-acpi.c | 14 ++++++++++++++
 include/linux/i2c.h         |  5 +++++
 2 files changed, 19 insertions(+)

Comments

Laurent Pinchart Nov. 30, 2020, 5:11 p.m. | #1
Hi Daniel,

Thank you for the patch.

On Mon, Nov 30, 2020 at 01:31:26PM +0000, Daniel Scally wrote:
> Some places in the kernel allow users to map resources to a device
> using device name (for example, gpiod_lookup_table). Currently
> this involves waiting for the i2c_client to have been registered so we
> can use dev_name(&client->dev). Adding this function means that we can
> achieve the same thing without having to wait to the i2c device.
> 
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---
> Changes since RFC v3:
> 
> 	- Patch introduced
> 
>  drivers/i2c/i2c-core-acpi.c | 14 ++++++++++++++
>  include/linux/i2c.h         |  5 +++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index 37c510d9347a..d3a653eac79e 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -497,6 +497,20 @@ struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
>  }
>  EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
>  
> +/**
> + * i2c_acpi_dev_name - Construct i2c device name for devs sourced from ACPI
> + * @adev:     ACPI device to construct the name for
> + *
> + * Prefixes "i2c-" to the ACPI device name, for use in i2c_dev_set_name() and
> + * also anywhere else in the kernel that needs to refer to an i2c device by
> + * name but before they have been instantiated.

The documentation should state that the caller must free the return
value.

> + */
> +char *i2c_acpi_dev_name(struct acpi_device *adev)
> +{
> +	return kasprintf(GFP_KERNEL, "i2c-%s", acpi_dev_name(adev));
> +}
> +EXPORT_SYMBOL_GPL(i2c_acpi_dev_name);
> +
>  #ifdef CONFIG_ACPI_I2C_OPREGION
>  static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
>  		u8 cmd, u8 *data, u8 data_len)
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 56622658b215..ab0e505b2ca6 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -995,6 +995,7 @@ bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
>  u32 i2c_acpi_find_bus_speed(struct device *dev);
>  struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
>  				       struct i2c_board_info *info);
> +char *i2c_acpi_dev_name(struct acpi_device *adev);
>  struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
>  #else
>  static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
> @@ -1011,6 +1012,10 @@ static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
>  {
>  	return ERR_PTR(-ENODEV);
>  }
> +static inline char *i2c_acpi_dev_name(struct acpi_device *adev)
> +{
> +	return NULL;
> +}
>  static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
>  {
>  	return NULL;
Daniel Scally Dec. 2, 2020, 10:44 p.m. | #2
On 30/11/2020 17:11, Laurent Pinchart wrote:
> Hi Daniel,
> 
> Thank you for the patch.
> 
> On Mon, Nov 30, 2020 at 01:31:26PM +0000, Daniel Scally wrote:
>> Some places in the kernel allow users to map resources to a device
>> using device name (for example, gpiod_lookup_table). Currently
>> this involves waiting for the i2c_client to have been registered so we
>> can use dev_name(&client->dev). Adding this function means that we can
>> achieve the same thing without having to wait to the i2c device.
>>
>> Signed-off-by: Daniel Scally <djrscally@gmail.com>
>> ---
>> Changes since RFC v3:
>>
>> 	- Patch introduced
>>
>>  drivers/i2c/i2c-core-acpi.c | 14 ++++++++++++++
>>  include/linux/i2c.h         |  5 +++++
>>  2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
>> index 37c510d9347a..d3a653eac79e 100644
>> --- a/drivers/i2c/i2c-core-acpi.c
>> +++ b/drivers/i2c/i2c-core-acpi.c
>> @@ -497,6 +497,20 @@ struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
>>  }
>>  EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
>>  
>> +/**
>> + * i2c_acpi_dev_name - Construct i2c device name for devs sourced from ACPI
>> + * @adev:     ACPI device to construct the name for
>> + *
>> + * Prefixes "i2c-" to the ACPI device name, for use in i2c_dev_set_name() and
>> + * also anywhere else in the kernel that needs to refer to an i2c device by
>> + * name but before they have been instantiated.
> 
> The documentation should state that the caller must free the return
> value.

Updated to include that - thanks

>> + */
>> +char *i2c_acpi_dev_name(struct acpi_device *adev)
>> +{
>> +	return kasprintf(GFP_KERNEL, "i2c-%s", acpi_dev_name(adev));
>> +}
>> +EXPORT_SYMBOL_GPL(i2c_acpi_dev_name);
>> +
>>  #ifdef CONFIG_ACPI_I2C_OPREGION
>>  static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
>>  		u8 cmd, u8 *data, u8 data_len)
>> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
>> index 56622658b215..ab0e505b2ca6 100644
>> --- a/include/linux/i2c.h
>> +++ b/include/linux/i2c.h
>> @@ -995,6 +995,7 @@ bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
>>  u32 i2c_acpi_find_bus_speed(struct device *dev);
>>  struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
>>  				       struct i2c_board_info *info);
>> +char *i2c_acpi_dev_name(struct acpi_device *adev);
>>  struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
>>  #else
>>  static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
>> @@ -1011,6 +1012,10 @@ static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
>>  {
>>  	return ERR_PTR(-ENODEV);
>>  }
>> +static inline char *i2c_acpi_dev_name(struct acpi_device *adev)
>> +{
>> +	return NULL;
>> +}
>>  static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
>>  {
>>  	return NULL;
>

Patch

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 37c510d9347a..d3a653eac79e 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -497,6 +497,20 @@  struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 }
 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 
+/**
+ * i2c_acpi_dev_name - Construct i2c device name for devs sourced from ACPI
+ * @adev:     ACPI device to construct the name for
+ *
+ * Prefixes "i2c-" to the ACPI device name, for use in i2c_dev_set_name() and
+ * also anywhere else in the kernel that needs to refer to an i2c device by
+ * name but before they have been instantiated.
+ */
+char *i2c_acpi_dev_name(struct acpi_device *adev)
+{
+	return kasprintf(GFP_KERNEL, "i2c-%s", acpi_dev_name(adev));
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_dev_name);
+
 #ifdef CONFIG_ACPI_I2C_OPREGION
 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 		u8 cmd, u8 *data, u8 data_len)
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 56622658b215..ab0e505b2ca6 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -995,6 +995,7 @@  bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
 u32 i2c_acpi_find_bus_speed(struct device *dev);
 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 				       struct i2c_board_info *info);
+char *i2c_acpi_dev_name(struct acpi_device *adev);
 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
 #else
 static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
@@ -1011,6 +1012,10 @@  static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
 {
 	return ERR_PTR(-ENODEV);
 }
+static inline char *i2c_acpi_dev_name(struct acpi_device *adev)
+{
+	return NULL;
+}
 static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
 {
 	return NULL;