Re: [PATCH net-next + leds v2 2/7] leds: add generic API for LEDs that can be controlled by hardware

[Randy Dunlap]

On 9/9/20 11:31 AM, Marek Behún wrote:
> On Wed, 9 Sep 2020 11:20:00 -0700
> Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> 
>> Hi,
>>
>> On 9/9/20 9:25 AM, Marek Behún wrote:
>>> Many an ethernet PHY (and other chips) supports various HW control
>>> modes for LEDs connected directly to them.
>>>
>>> This patch adds a generic API for registering such LEDs when
>>> described in device tree. This API also exposes generic way to
>>> select between these hardware control modes.
>>>
>>> This API registers a new private LED trigger called dev-hw-mode.
>>> When this trigger is enabled for a LED, the various HW control
>>> modes which are supported by the device for given LED can be
>>> get/set via hw_mode sysfs file.
>>>
>>> Signed-off-by: Marek Behún <marek.behun@xxxxxx>
>>> ---
>>>  .../sysfs-class-led-trigger-dev-hw-mode       |   8 +
>>>  drivers/leds/Kconfig                          |  10 +
>>>  drivers/leds/Makefile                         |   1 +
>>>  drivers/leds/leds-hw-controlled.c             | 227
>>> ++++++++++++++++++ include/linux/leds-hw-controlled.h            |
>>> 74 ++++++ 5 files changed, 320 insertions(+)
>>>  create mode 100644
>>> Documentation/ABI/testing/sysfs-class-led-trigger-dev-hw-mode
>>> create mode 100644 drivers/leds/leds-hw-controlled.c create mode
>>> 100644 include/linux/leds-hw-controlled.h 
>>
>>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>>> index 1c181df24eae4..5e47ab21aafb4 100644
>>> --- a/drivers/leds/Kconfig
>>> +++ b/drivers/leds/Kconfig
>>> @@ -49,6 +49,16 @@ config LEDS_BRIGHTNESS_HW_CHANGED
>>>  
>>>  	  See Documentation/ABI/testing/sysfs-class-led for
>>> details. 
>>> +config LEDS_HW_CONTROLLED
>>> +	bool "API for LEDs that can be controlled by hardware"
>>> +	depends on LEDS_CLASS  
>>
>> 	depends on OF || COMPILE_TEST
>> ?
>>
> 
> I specifically did not add OF dependency so that this can be also used
> on non-OF systems. A device driver may register such LED itself...
> That's why hw_controlled_led_brightness_set symbol is exported.
> 
> Do you think I shouldn't do it?

I have no problem with it as it is.

>>> +	select LEDS_TRIGGERS
>>> +	help
>>> +	  This option enables support for a generic API via which
>>> other drivers
>>> +	  can register LEDs that can be put into hardware
>>> controlled mode, eg.  

thanks.
-- 
~Randy