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From: Jon Hunter <jonathanh@nvidia.com>
To: Dipen Patel <dipenp@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 17:42:37 +0100	[thread overview]
Message-ID: <8d3257f3-54b1-e658-245d-3a070aba44c4@nvidia.com> (raw)
In-Reply-To: <65bf01e1-66e1-7eec-0052-4d707f4a3f6b@nvidia.com>


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.

Jon

--
nvpublic

  reply	other threads:[~2021-08-03 16:42 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 [this message]
2021-08-03 22:51         ` Dipen Patel
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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