Re: [RFC PATCH v1 00/20] Review Request: Add support for Intel PMC

[Dipen Patel <dipenp@nvidia.com>]

Thanks Linus for referring. I will take a look.

@Sowjanya: I have recently sent out the RFC v2 of the HTE (https://patchwork.ozlabs.org/project/linux-tegra/list/?series=264896).

Please have a look and see if you can add TIO as one of the provider. That patch has necessary GPIOLIB and GPIO-CDEV changes

which can help userspace and in kernel driver retrieve GPIO realtime timestamps.


Best,

Dipen Patel

On 9/16/21 2:21 PM, Linus Walleij wrote:
> Hi Sowjanya,
>
> thanks for your patches!
>
> On Tue, Aug 24, 2021 at 6:48 PM <lakshmi.sowjanya.d@intel.com> wrote:
>
>> From: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
>>
>> Starting with Intel(R) Tiger Lake and Elkhart Lake platforms the PMC
>> hardware adds the Timed I/O hardware interface.
>>
>> The Timed I/O hardware implements some functionality similar to GPIO
>> with added timing logic that is driven by the Always Running Timer
>> (ART).
>>
>> The Timed I/O Hardware implement 3 basic functions:
>>   * Input Timestamping
>>   * Single Shot Timed Output
>>   * Periodic Timed Output
>>
>>  Please help to review the changes.
> This looks very similar to the usecase proposed for the HTE
> Hardware Timestamping Engine, proposed by Dipen Patel
> for the nVidia 194 and which is currently in RFC:
> https://lore.kernel.org/linux-gpio/20210625235532.19575-1-dipenp@nvidia.com/
>
> Please review this new subsystem and see if you can just
> make a slot-in driver using Dipen's patches instead.
>
> Dipen: please have a look at Sowjanya's patches to see
> if this hardware is similar to yours.
>
> Sometimes several vendors come up with similar hardware
> around the same time, because of industry trends, so I would
> not be surprised if these two hardwares address the very
> same usecase.
>
> Yours,
> Linus Walleij