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@xxxxxxxxxx>
>> ---
>> 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.
>
> Jon
>
