diff mbox series

[15/20] drivers/gpu/drm/i915/display: remove I2C_CLASS_DDC support

Message ID 20231113112344.719-16-hkallweit1@gmail.com
State New
Headers
Series remove I2C_CLASS_DDC support |

Commit Message

Heiner Kallweit Nov. 13, 2023, 11:23 a.m. UTC 
  After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
Class-based device auto-detection is a legacy mechanism and shouldn't
be used in new code. So we can remove this class completely now.

Preferably this series should be applied via the i2c tree.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

---
 drivers/gpu/drm/i915/display/intel_gmbus.c |    1 -
 drivers/gpu/drm/i915/display/intel_sdvo.c  |    1 -
 2 files changed, 2 deletions(-)

Comments

Jani Nikula Nov. 13, 2023, 12:17 p.m. UTC | #1 
On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
> After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
> olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
> Class-based device auto-detection is a legacy mechanism and shouldn't
> be used in new code. So we can remove this class completely now.

So this is copy-pasted to all commits and the cover letter, but please
do explain why there are no functional changes here (or are there?),
without me having to go through the i2c stack and try to find the
commits alluded to in "After removal of the legacy ...".

What does this mean?


BR,
Jani.


>
> Preferably this series should be applied via the i2c tree.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>
> ---
>  drivers/gpu/drm/i915/display/intel_gmbus.c |    1 -
>  drivers/gpu/drm/i915/display/intel_sdvo.c  |    1 -
>  2 files changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
> index 40d7b6f3f..e9e4dcf34 100644
> --- a/drivers/gpu/drm/i915/display/intel_gmbus.c
> +++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
> @@ -899,7 +899,6 @@ int intel_gmbus_setup(struct drm_i915_private *i915)
>  		}
>  
>  		bus->adapter.owner = THIS_MODULE;
> -		bus->adapter.class = I2C_CLASS_DDC;
>  		snprintf(bus->adapter.name,
>  			 sizeof(bus->adapter.name),
>  			 "i915 gmbus %s", gmbus_pin->name);
> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
> index a636f42ce..5e64d1baf 100644
> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> @@ -3311,7 +3311,6 @@ intel_sdvo_init_ddc_proxy(struct intel_sdvo_ddc *ddc,
>  	ddc->ddc_bus = ddc_bus;
>  
>  	ddc->ddc.owner = THIS_MODULE;
> -	ddc->ddc.class = I2C_CLASS_DDC;
>  	snprintf(ddc->ddc.name, I2C_NAME_SIZE, "SDVO %c DDC%d",
>  		 port_name(sdvo->base.port), ddc_bus);
>  	ddc->ddc.dev.parent = &pdev->dev;
>
Heiner Kallweit Nov. 13, 2023, 12:32 p.m. UTC | #2 
On 13.11.2023 13:17, Jani Nikula wrote:
> On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>> After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
>> olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
>> Class-based device auto-detection is a legacy mechanism and shouldn't
>> be used in new code. So we can remove this class completely now.
> 
> So this is copy-pasted to all commits and the cover letter, but please
> do explain why there are no functional changes here (or are there?),
> without me having to go through the i2c stack and try to find the
> commits alluded to in "After removal of the legacy ...".
> 
Legacy eeprom driver was marked deprecated 4 yrs ago with:
3079b54aa9a0 ("eeprom: Warn that the driver is deprecated")
Now it has been removed with:
0113a99b8a75 ("eeprom: Remove deprecated legacy eeprom driver")

Declaration of I2C_CLASS_DDC support is a no-op now, so there's
no functional change in this patch.

If loaded manually, the legacy eeprom driver exposed the DDC EEPROM
to userspace. If this functionality is needed, then now the DDC
EEPROM has to be explicitly instantiated using at24.

See also:
https://docs.kernel.org/i2c/instantiating-devices.html


> What does this mean?
> 
> 
> BR,
> Jani.
> 
Heiner

> 
>>
>> Preferably this series should be applied via the i2c tree.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>
>> ---
>>  drivers/gpu/drm/i915/display/intel_gmbus.c |    1 -
>>  drivers/gpu/drm/i915/display/intel_sdvo.c  |    1 -
>>  2 files changed, 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
>> index 40d7b6f3f..e9e4dcf34 100644
>> --- a/drivers/gpu/drm/i915/display/intel_gmbus.c
>> +++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
>> @@ -899,7 +899,6 @@ int intel_gmbus_setup(struct drm_i915_private *i915)
>>  		}
>>  
>>  		bus->adapter.owner = THIS_MODULE;
>> -		bus->adapter.class = I2C_CLASS_DDC;
>>  		snprintf(bus->adapter.name,
>>  			 sizeof(bus->adapter.name),
>>  			 "i915 gmbus %s", gmbus_pin->name);
>> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
>> index a636f42ce..5e64d1baf 100644
>> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
>> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
>> @@ -3311,7 +3311,6 @@ intel_sdvo_init_ddc_proxy(struct intel_sdvo_ddc *ddc,
>>  	ddc->ddc_bus = ddc_bus;
>>  
>>  	ddc->ddc.owner = THIS_MODULE;
>> -	ddc->ddc.class = I2C_CLASS_DDC;
>>  	snprintf(ddc->ddc.name, I2C_NAME_SIZE, "SDVO %c DDC%d",
>>  		 port_name(sdvo->base.port), ddc_bus);
>>  	ddc->ddc.dev.parent = &pdev->dev;
>>
>
Jani Nikula Nov. 13, 2023, 5:50 p.m. UTC | #3 
On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
> On 13.11.2023 13:17, Jani Nikula wrote:
>> On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>> After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
>>> olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
>>> Class-based device auto-detection is a legacy mechanism and shouldn't
>>> be used in new code. So we can remove this class completely now.
>> 
>> So this is copy-pasted to all commits and the cover letter, but please
>> do explain why there are no functional changes here (or are there?),
>> without me having to go through the i2c stack and try to find the
>> commits alluded to in "After removal of the legacy ...".
>> 
> Legacy eeprom driver was marked deprecated 4 yrs ago with:
> 3079b54aa9a0 ("eeprom: Warn that the driver is deprecated")
> Now it has been removed with:
> 0113a99b8a75 ("eeprom: Remove deprecated legacy eeprom driver")
>
> Declaration of I2C_CLASS_DDC support is a no-op now, so there's
> no functional change in this patch.
>
> If loaded manually, the legacy eeprom driver exposed the DDC EEPROM
> to userspace. If this functionality is needed, then now the DDC
> EEPROM has to be explicitly instantiated using at24.
>
> See also:
> https://docs.kernel.org/i2c/instantiating-devices.html

I'll take your word for it. Though none of the documentation I can find
say that setting the class is legacy or deprecated or should be
avoided. *shrug*.

Acked-by: Jani Nikula <jani.nikula@intel.com>


>
>
>> What does this mean?
>> 
>> 
>> BR,
>> Jani.
>> 
> Heiner
>
>> 
>>>
>>> Preferably this series should be applied via the i2c tree.
>>>
>>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>>
>>> ---
>>>  drivers/gpu/drm/i915/display/intel_gmbus.c |    1 -
>>>  drivers/gpu/drm/i915/display/intel_sdvo.c  |    1 -
>>>  2 files changed, 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
>>> index 40d7b6f3f..e9e4dcf34 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_gmbus.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
>>> @@ -899,7 +899,6 @@ int intel_gmbus_setup(struct drm_i915_private *i915)
>>>  		}
>>>  
>>>  		bus->adapter.owner = THIS_MODULE;
>>> -		bus->adapter.class = I2C_CLASS_DDC;
>>>  		snprintf(bus->adapter.name,
>>>  			 sizeof(bus->adapter.name),
>>>  			 "i915 gmbus %s", gmbus_pin->name);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
>>> index a636f42ce..5e64d1baf 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
>>> @@ -3311,7 +3311,6 @@ intel_sdvo_init_ddc_proxy(struct intel_sdvo_ddc *ddc,
>>>  	ddc->ddc_bus = ddc_bus;
>>>  
>>>  	ddc->ddc.owner = THIS_MODULE;
>>> -	ddc->ddc.class = I2C_CLASS_DDC;
>>>  	snprintf(ddc->ddc.name, I2C_NAME_SIZE, "SDVO %c DDC%d",
>>>  		 port_name(sdvo->base.port), ddc_bus);
>>>  	ddc->ddc.dev.parent = &pdev->dev;
>>>
>> 
>
Heiner Kallweit Nov. 13, 2023, 6:20 p.m. UTC | #4 
On 13.11.2023 18:50, Jani Nikula wrote:
> On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>> On 13.11.2023 13:17, Jani Nikula wrote:
>>> On Mon, 13 Nov 2023, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>>> After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
>>>> olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
>>>> Class-based device auto-detection is a legacy mechanism and shouldn't
>>>> be used in new code. So we can remove this class completely now.
>>>
>>> So this is copy-pasted to all commits and the cover letter, but please
>>> do explain why there are no functional changes here (or are there?),
>>> without me having to go through the i2c stack and try to find the
>>> commits alluded to in "After removal of the legacy ...".
>>>
>> Legacy eeprom driver was marked deprecated 4 yrs ago with:
>> 3079b54aa9a0 ("eeprom: Warn that the driver is deprecated")
>> Now it has been removed with:
>> 0113a99b8a75 ("eeprom: Remove deprecated legacy eeprom driver")
>>
>> Declaration of I2C_CLASS_DDC support is a no-op now, so there's
>> no functional change in this patch.
>>
>> If loaded manually, the legacy eeprom driver exposed the DDC EEPROM
>> to userspace. If this functionality is needed, then now the DDC
>> EEPROM has to be explicitly instantiated using at24.
>>
>> See also:
>> https://docs.kernel.org/i2c/instantiating-devices.html
> 
> I'll take your word for it. Though none of the documentation I can find
> say that setting the class is legacy or deprecated or should be
> avoided. *shrug*.
> 
I have to agree that it's not obvious that class-based instantiation
is considered a legacy mechanism. The commit message of this 9 yrs old
commit provides an explanation.

0c176170089c ("i2c: add deprecation warning for class based instantiation")

> Acked-by: Jani Nikula <jani.nikula@intel.com>
> 
Thanks

> 
>>
>>
>>> What does this mean?
>>>
>>>
>>> BR,
>>> Jani.
>>>
>> Heiner
>>
>>>
>>>>
>>>> Preferably this series should be applied via the i2c tree.
>>>>
>>>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>>>
>>>> ---
>>>>  drivers/gpu/drm/i915/display/intel_gmbus.c |    1 -
>>>>  drivers/gpu/drm/i915/display/intel_sdvo.c  |    1 -
>>>>  2 files changed, 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
>>>> index 40d7b6f3f..e9e4dcf34 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_gmbus.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
>>>> @@ -899,7 +899,6 @@ int intel_gmbus_setup(struct drm_i915_private *i915)
>>>>  		}
>>>>  
>>>>  		bus->adapter.owner = THIS_MODULE;
>>>> -		bus->adapter.class = I2C_CLASS_DDC;
>>>>  		snprintf(bus->adapter.name,
>>>>  			 sizeof(bus->adapter.name),
>>>>  			 "i915 gmbus %s", gmbus_pin->name);
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
>>>> index a636f42ce..5e64d1baf 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
>>>> @@ -3311,7 +3311,6 @@ intel_sdvo_init_ddc_proxy(struct intel_sdvo_ddc *ddc,
>>>>  	ddc->ddc_bus = ddc_bus;
>>>>  
>>>>  	ddc->ddc.owner = THIS_MODULE;
>>>> -	ddc->ddc.class = I2C_CLASS_DDC;
>>>>  	snprintf(ddc->ddc.name, I2C_NAME_SIZE, "SDVO %c DDC%d",
>>>>  		 port_name(sdvo->base.port), ddc_bus);
>>>>  	ddc->ddc.dev.parent = &pdev->dev;
>>>>
>>>
>>
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c
index 40d7b6f3f..e9e4dcf34 100644
--- a/drivers/gpu/drm/i915/display/intel_gmbus.c
+++ b/drivers/gpu/drm/i915/display/intel_gmbus.c
@@ -899,7 +899,6 @@  int intel_gmbus_setup(struct drm_i915_private *i915)
 		}
 
 		bus->adapter.owner = THIS_MODULE;
-		bus->adapter.class = I2C_CLASS_DDC;
 		snprintf(bus->adapter.name,
 			 sizeof(bus->adapter.name),
 			 "i915 gmbus %s", gmbus_pin->name);
diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
index a636f42ce..5e64d1baf 100644
--- a/drivers/gpu/drm/i915/display/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
@@ -3311,7 +3311,6 @@  intel_sdvo_init_ddc_proxy(struct intel_sdvo_ddc *ddc,
 	ddc->ddc_bus = ddc_bus;
 
 	ddc->ddc.owner = THIS_MODULE;
-	ddc->ddc.class = I2C_CLASS_DDC;
 	snprintf(ddc->ddc.name, I2C_NAME_SIZE, "SDVO %c DDC%d",
 		 port_name(sdvo->base.port), ddc_bus);
 	ddc->ddc.dev.parent = &pdev->dev;