Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates
 216.228.112.34 as permitted sender) receiver=protection.outlook.com;
 client-ip=216.228.112.34; helo=mail.nvidia.com;
Subject: Re: [RFC PATCH v1 00/20] Review Request: Add support for Intel PMC
To:     Linus Walleij <linus.walleij@linaro.org>,
        "D, Lakshmi Sowjanya" <lakshmi.sowjanya.d@intel.com>
CC:     "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Mark Gross <mgross@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        "Saha, Tamal" <tamal.saha@intel.com>, <bala.senthil@intel.com>
References: <20210824164801.28896-1-lakshmi.sowjanya.d@intel.com>
 <CACRpkdZEp0FZOefBPP_sR4g6rKzeKQhpdL-XHYO+CRt5MfTrYg@mail.gmail.com>
From:   Dipen Patel <dipenp@nvidia.com>
Message-ID: <f5f97c30-2b4e-2490-2197-1d5a108992d1@nvidia.com>
Date:   Mon, 11 Oct 2021 14:14:12 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
MIME-Version: 1.0
In-Reply-To: <CACRpkdZEp0FZOefBPP_sR4g6rKzeKQhpdL-XHYO+CRt5MfTrYg@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Content-Language: en-US
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Oct 2021 21:14:03.8467
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 618fba30-ef3b-43f4-c81b-08d98cfc0dc1
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.34];Helo=[mail.nvidia.com]
X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT022.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR12MB2488
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

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