[PATCH v12 14/17] counter: Implement *_component_id sysfs attributes

[David Lechner]

On 7/11/21 8:28 AM, Jonathan Cameron wrote:
> On Sat, 10 Jul 2021 12:06:53 -0500
> David Lechner <david at lechnology.com> wrote:
> 
>> On 7/5/21 3:19 AM, William Breathitt Gray wrote:
>>> The Generic Counter chrdev interface expects users to supply component
>>> IDs in order to select extensions for requests. In order for users to
>>> know what component ID belongs to which extension this information must
>>> be exposed. The *_component_id attribute provides a way for users to
>>> discover what component ID belongs to which respective extension.
>>>
>>> Cc: David Lechner <david at lechnology.com>
>>> Cc: Gwendal Grignou <gwendal at chromium.org>
>>> Cc: Dan Carpenter <dan.carpenter at oracle.com>
>>> Signed-off-by: William Breathitt Gray <vilhelm.gray at gmail.com>
>>> ---
>>>    Documentation/ABI/testing/sysfs-bus-counter | 16 ++++++++++-
>>>    drivers/counter/counter-sysfs.c             | 30 ++++++++++++++++-----
>>>    2 files changed, 39 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
>>> index 9809d8a47431..e0e99adb0ecc 100644
>>> --- a/Documentation/ABI/testing/sysfs-bus-counter
>>> +++ b/Documentation/ABI/testing/sysfs-bus-counter
>>> @@ -203,12 +203,26 @@ Description:
>>>    		both edges:
>>>    			Any state transition.
>>>    
>>> +What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/direction_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/enable_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/error_noise_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/prescaler_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/preset_component_id
>>> +What:		/sys/bus/counter/devices/counterX/countY/preset_enable_component_id
>>>    What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
>>> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
>>> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
>>> +What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
>>> +What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
>>> +What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
>>
>> Could we just write a single line?
>>
>> What:		/sys/bus/counter/devices/counterX/signalY/<component>_component_id
> 
> Not nice for grepping so I think it's better to call them out explicitly.
> 
> There has been a proposal to check this ABI doc against running kernels, and if we have
> too many wild cards that becomes very difficult to do.
> 
> Jonathan
> 
>>
>>>    KernelVersion:	5.15

Makes sense. Do we start a new group of similar names with the same
description for each kernel release that includes new attributes then?

>>>    Contact:	linux-iio at vger.kernel.org
>>>    Description:
>>>    		Read-only attribute that indicates the component ID of the
>>> -		respective Synapse of Count Y for Signal Z.
>>> +		respective extension or Synapse.
>>>