On 3/23/23 08:29, Dipen Patel wrote: > Make Tegra194 API document generic to make it applicable for > current and future tegra hte providers. > > Signed-off-by: Dipen Patel <dipenp@xxxxxxxxxx> > --- > Documentation/driver-api/hte/tegra194-hte.rst | 33 +++++++++---------- > 1 file changed, 16 insertions(+), 17 deletions(-) > While generalizing the doc, the doc file name should also be renamed (i.e. to tegra-hte.rst). > diff --git a/Documentation/driver-api/hte/tegra194-hte.rst b/Documentation/driver-api/hte/tegra194-hte.rst > index f2d617265546..85e654772782 100644 > --- a/Documentation/driver-api/hte/tegra194-hte.rst > +++ b/Documentation/driver-api/hte/tegra194-hte.rst > @@ -5,25 +5,25 @@ HTE Kernel provider driver > > Description > ----------- > -The Nvidia tegra194 HTE provider driver implements two GTE > -(Generic Timestamping Engine) instances: 1) GPIO GTE and 2) LIC > -(Legacy Interrupt Controller) IRQ GTE. Both GTE instances get the > -timestamp from the system counter TSC which has 31.25MHz clock rate, and the > -driver converts clock tick rate to nanoseconds before storing it as timestamp > -value. > +The Nvidia tegra HTE provider also known as GTE (Generic Timestamping Engine) > +driver implements two GTE instances: 1) GPIO GTE and 2) LIC > +(Legacy Interrupt Controller) IRQ GTE. Both GTE instances get the timestamp > +from the system counter TSC which has 31.25MHz clock rate, and the driver > +converts clock tick rate to nanoseconds before storing it as timestamp value. > > GPIO GTE > -------- > > This GTE instance timestamps GPIO in real time. For that to happen GPIO > -needs to be configured as input. The always on (AON) GPIO controller instance > -supports timestamping GPIOs in real time and it has 39 GPIO lines. The GPIO GTE > -and AON GPIO controller are tightly coupled as it requires very specific bits > -to be set in GPIO config register before GPIO GTE can be used, for that GPIOLIB > -adds two optional APIs as below. The GPIO GTE code supports both kernel > -and userspace consumers. The kernel space consumers can directly talk to HTE > -subsystem while userspace consumers timestamp requests go through GPIOLIB CDEV > -framework to HTE subsystem. > +needs to be configured as input. Only the always on (AON) GPIO controller > +instance supports timestamping GPIOs in real time as it is tightly coupled with > +the GPIO GTE. To support this, GPIOLIB adds two optional APIs as mentioned > +below. The GPIO GTE code supports both kernel and userspace consumers. The > +kernel space consumers can directly talk to HTE subsystem while userspace > +consumers timestamp requests go through GPIOLIB CDEV framework to HTE > +subsystem. The hte devicetree binding described at > +``Documentation/devicetree/bindings/timestamp`` provides an example of how a > +consumer can request an GPIO line. > > See gpiod_enable_hw_timestamp_ns() and gpiod_disable_hw_timestamp_ns(). > > @@ -34,9 +34,8 @@ returns the timestamp in nanoseconds. > LIC (Legacy Interrupt Controller) IRQ GTE > ----------------------------------------- > > -This GTE instance timestamps LIC IRQ lines in real time. There are 352 IRQ > -lines which this instance can add timestamps to in real time. The hte > -devicetree binding described at ``Documentation/devicetree/bindings/timestamp`` > +This GTE instance timestamps LIC IRQ lines in real time. The hte devicetree > +binding described at ``Documentation/devicetree/bindings/timestamp`` > provides an example of how a consumer can request an IRQ line. Since it is a > one-to-one mapping with IRQ GTE provider, consumers can simply specify the IRQ > number that they are interested in. There is no userspace consumer support for The wording LGTM, thanks! Reviewed-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx> -- An old man doll... just what I always wanted! - Clara
