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From: Dipen Patel <dipenp@nvidia.com>
To: Jon Hunter <jonathanh@nvidia.com>, <thierry.reding@gmail.com>,
	<linux-kernel@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-gpio@vger.kernel.org>, <linus.walleij@linaro.org>,
	<bgolaszewski@baylibre.com>, <warthog618@gmail.com>,
	<devicetree@vger.kernel.org>, <linux-doc@vger.kernel.org>,
	<robh+dt@kernel.org>
Subject: Re: [RFC 08/11] gpiolib: cdev: Add hardware timestamp clock type
Date: Tue, 3 Aug 2021 15:51:31 -0700	[thread overview]
Message-ID: <f0d8da75-6e31-5432-6909-8eab6960b787@nvidia.com> (raw)
In-Reply-To: <8d3257f3-54b1-e658-245d-3a070aba44c4@nvidia.com>


On 8/3/21 9:42 AM, Jon Hunter wrote:
>
> On 30/07/2021 03:33, Dipen Patel wrote:
>>
>> On 7/9/21 1:30 AM, Jon Hunter wrote:
>>> On 26/06/2021 00:55, Dipen Patel wrote:
>>>> This patch adds new clock type for the GPIO controller which can
>>>> timestamp gpio lines using hardware means. To expose such
>>>> functionalities to the userspace, code has been added in this patch
>>>> where during line create call, it checks for new clock type and if
>>>> requested, calls hardware timestamp related API from gpiolib.c.
>>>> During line change event, it retrieves timestamp in nano seconds by
>>>> calling gpiod_get_hw_timestamp API from gpiolib.c. At the line release,
>>>> it disables this functionality by calling gpiod_hw_timestamp_control.
>>>>
>>>> Signed-off-by: Dipen Patel <dipenp@nvidia.com>
>>>> ---
>>>>   drivers/gpio/gpiolib-cdev.c | 65 +++++++++++++++++++++++++++++++++++--
>>>>   include/uapi/linux/gpio.h   |  1 +
>>>>   2 files changed, 64 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
>>>> index 1631727bf0da..9f98c727e937 100644
>>>> --- a/drivers/gpio/gpiolib-cdev.c
>>>> +++ b/drivers/gpio/gpiolib-cdev.c
>>>> @@ -518,6 +518,7 @@ struct linereq {
>>>>        GPIO_V2_LINE_DRIVE_FLAGS | \
>>>>        GPIO_V2_LINE_EDGE_FLAGS | \
>>>>        GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
>>>> +     GPIO_V2_LINE_FLAG_EVENT_CLOCK_HARDWARE | \
>>>>        GPIO_V2_LINE_BIAS_FLAGS)
>>>>     static void linereq_put_event(struct linereq *lr,
>>>> @@ -540,9 +541,20 @@ static void linereq_put_event(struct linereq *lr,
>>>>     static u64 line_event_timestamp(struct line *line)
>>>>   {
>>>> +    bool block;
>>>> +
>>>>       if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
>>>>           return ktime_get_real_ns();
>>>>   +    if (test_bit(FLAG_EVENT_CLOCK_HARDWARE, &line->desc->flags)) {
>>>> +        if (irq_count())
>>>> +            block = false;
>>>> +        else
>>>> +            block = true;
>>>> +
>>>> +        return gpiod_get_hw_timestamp(line->desc, block);
>>>> +    }
>>>> +
>>>>       return ktime_get_ns();
>>>>   }
>>>
>>> Looking at line_event_timestamp() and the callers of this function, it
>>> appears that this should always return nanoseconds. Does
>>> gpiod_get_hw_timestamp() return nanoseconds?
>> Yes, it returns in ns to align with line_event_timestamp.
>
>
> It might be worth updating the function name to gpiod_get_hw_timestamp_ns() so that this is clear.
Wouldn't be sufficient to right into its description rather embed in API name?
>
> Jon
>
> -- 
> nvpublic

  reply	other threads:[~2021-08-03 22:42 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 23:55 [RFC 00/11] Intro to Hardware timestamping engine Dipen Patel
2021-06-25 23:55 ` [RFC 01/11] Documentation: Add HTE subsystem guide Dipen Patel
2021-07-04 18:55   ` Jonathan Cameron
2021-07-27 23:44     ` Dipen Patel
2021-08-01 15:24       ` Jonathan Cameron
2021-06-25 23:55 ` [RFC 02/11] drivers: Add HTE subsystem Dipen Patel
2021-06-27 17:40   ` Randy Dunlap
2021-07-04 20:15   ` Jonathan Cameron
2021-07-04 20:45     ` Jonathan Cameron
2021-07-28  5:12       ` Dipen Patel
2021-08-01 16:48         ` Jonathan Cameron
2021-07-28  4:38     ` Dipen Patel
2021-08-01 16:13       ` Jonathan Cameron
2021-09-14  5:43         ` Dipen Patel
2021-09-26 15:42           ` Jonathan Cameron
2021-07-05  7:30   ` Greg KH
2021-07-28  0:34     ` Dipen Patel
2021-06-25 23:55 ` [RFC 03/11] hte: Add tegra194 HTE kernel provider Dipen Patel
2021-07-01 14:21   ` Kent Gibson
2021-07-28 23:59     ` Dipen Patel
2021-07-30  7:01       ` Dipen Patel
2021-07-31 15:43       ` Kent Gibson
2021-08-03 22:40         ` Dipen Patel
2021-08-03 23:02           ` Kent Gibson
2021-08-07  2:41         ` Dipen Patel
2021-08-07  3:07           ` Kent Gibson
2021-08-07  4:52             ` Dipen Patel
2021-08-07  4:51               ` Kent Gibson
2021-08-07  5:35                 ` Dipen Patel
2021-08-07  5:42                   ` Kent Gibson
2021-08-07  5:47                   ` Dipen Patel
2021-07-04 20:27   ` Jonathan Cameron
2021-07-29  2:42     ` Dipen Patel
2021-07-08 23:33   ` Michał Mirosław
2021-07-29  2:43     ` Dipen Patel
2021-06-25 23:55 ` [RFC 04/11] dt-bindings: Add HTE bindings Dipen Patel
2021-06-27 10:56   ` Linus Walleij
2021-07-30  1:32     ` Dipen Patel
2021-07-01 14:02   ` Rob Herring
2021-07-30  1:56     ` Dipen Patel
2021-07-01 15:54   ` Rob Herring
2021-07-30  1:58     ` Dipen Patel
2021-06-25 23:55 ` [RFC 05/11] hte: Add Tegra194 IRQ HTE test driver Dipen Patel
2021-06-27 17:42   ` Randy Dunlap
2021-06-25 23:55 ` [RFC 06/11] gpiolib: Add HTE support Dipen Patel
2021-06-27 11:41   ` Linus Walleij
2021-07-01 14:24   ` Kent Gibson
2021-07-30  2:25     ` Dipen Patel
2021-07-31  5:13       ` Kent Gibson
2021-06-25 23:55 ` [RFC 07/11] gpio: tegra186: Add HTE in gpio-tegra186 driver Dipen Patel
2021-06-25 23:55 ` [RFC 08/11] gpiolib: cdev: Add hardware timestamp clock type Dipen Patel
2021-06-27 11:38   ` Linus Walleij
2021-06-27 11:49   ` Linus Walleij
2021-07-30  3:16     ` Dipen Patel
2021-07-01 14:24   ` Kent Gibson
2021-07-30  3:07     ` Dipen Patel
2021-07-31  6:05       ` Kent Gibson
2021-08-03 22:41         ` Dipen Patel
2021-08-03 22:38           ` Kent Gibson
2021-07-09  8:30   ` Jon Hunter
2021-07-30  2:33     ` Dipen Patel
2021-08-03 16:42       ` Jon Hunter
2021-08-03 22:51         ` Dipen Patel [this message]
2021-08-03 23:09           ` Kent Gibson
2021-06-25 23:55 ` [RFC 09/11] tools: gpio: Add new hardware " Dipen Patel
2021-06-27 11:36   ` Linus Walleij
2021-07-30  3:17     ` Dipen Patel
2021-07-31  6:16       ` Kent Gibson
2021-08-11  9:11         ` Linus Walleij
2021-06-25 23:55 ` [RFC 10/11] hte: Add tegra GPIO HTE test driver Dipen Patel
2021-06-27 17:43   ` Randy Dunlap
2021-06-25 23:55 ` [RFC 11/11] MAINTAINERS: Added HTE Subsystem Dipen Patel
2021-06-27 13:07 ` [RFC 00/11] Intro to Hardware timestamping engine Andy Shevchenko
2021-06-27 14:40   ` Linus Walleij
2021-06-28 12:02     ` Andy Shevchenko

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