Roger, On 13/01/23 15:48, Roger Quadros wrote: > Hi, > > On 11/01/2023 13:44, Siddharth Vadapalli wrote: >> The CPTS driver is capable of configuring GENFy (Periodic Signal Generator >> Function) present in the CPTS module, to generate periodic output signals >> with a custom time period. In order to generate a PPS signal on the GENFy >> output, the device-tree property "ti,pps" has to be used. The "ti,pps" >> property is used to declare the mapping between the CPTS HWx_TS_PUSH >> (Hardware Timestamp trigger) input and the GENFy output that is configured >> to generate a PPS signal. The mapping is of the form: >> <x-1 y> >> where the value x corresponds to HWx_TS_PUSH input (1-based indexing) and >> the value y corresponds to GENFy (0-based indexing). > > You mean there is no HWx_TX_PUSH0 pin? so user needs to use 0 for HWx_TX_PUSH1 pin? The HWx_TX_PUSH pins correspond to the cpts_hw1_push, cpts_hw2_push,..., cpts_hw8_push pins. The names are documented at: Link: https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am62x/interrupt_cfg.html#timesync-event-router0-interrupt-router-output-destinations Thus, considering that the documentation uses 1-based indexing, I wanted to indicate that the driver expects 0-based indexing, and therefore the user would have to provide (x-1) for cpsw_hwx_push pin. > > Can you please define macros for HWx_TS_PUSH and GENFy so we avoid > human error with this different indexing methods? > > DT should contain the name exactly in hardware. > > So if pin is called HWx_TX_PUSH1 in hardware then DT should contain HWx_TX_PUSH(1). The pins are called HW1_TX_PUSH, HW2_TX_PUSH and so on. This 1-based indexing is followed in the Technical Reference Manual. Similarly, the documentation in the link above also uses 1-based indexing: cpts_hw1_push, cpts_hw2_push, and so on. However, for the GENFy pins, the documentation consistently uses 0-based indexing. Thus, the driver expects indices that are 0-based and the user is expected to convert the x to x-1 for the HWx_TX_PUSH pins while the y in GENFy pins can be used directly as it is already 0-based indexing. > >> >> To verify that the signal is a PPS signal, the GENFy output signal is fed >> into the CPTS HWx_TS_PUSH input, which generates a timestamp event on the >> rising edge of the GENFy signal. The GENFy output signal can be routed to >> the HWx_TS_PUSH input by using the Time Sync Router. This is done by >> mentioning the mapping between the GENFy output and the HWx_TS_PUSH input >> within the "timesync_router" device-tree node. >> >> The Input Sources to the Time Sync Router are documented at: [1] >> The Output Destinations of the Time Sync Router are documented at: [2] >> >> The PPS signal can be verified using testptp and ppstest tools as follows: >> # ./testptp -d /dev/ptp0 -P 1 >> pps for system time request okay >> # ./ppstest /dev/pps0 >> trying PPS source "/dev/pps0" >> found PPS source "/dev/pps0" >> ok, found 1 source(s), now start fetching data... >> source 0 - assert 48.000000013, sequence: 8 - clear 0.000000000, sequence: 0 >> source 0 - assert 49.000000013, sequence: 9 - clear 0.000000000, sequence: 0 >> source 0 - assert 50.000000013, sequence: 10 - clear 0.000000000, sequence: 0 >> >> Add an example in the device-tree, enabling PPS generation on GENF1. The >> HW3_TS_PUSH Timestamp trigger input is used to verify the PPS signal. >> >> [1] >> Link: https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am62x/interrupt_cfg.html#timesync-event-router0-interrupt-router-input-sources >> [2] >> Link: https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am62x/interrupt_cfg.html#timesync-event-router0-interrupt-router-output-destinations >> >> Signed-off-by: Siddharth Vadapalli <s-vadapalli@xxxxxx> >> --- >> arch/arm64/boot/dts/ti/k3-am625-sk.dts | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/arch/arm64/boot/dts/ti/k3-am625-sk.dts b/arch/arm64/boot/dts/ti/k3-am625-sk.dts >> index 4f179b146cab..962a922cc94b 100644 >> --- a/arch/arm64/boot/dts/ti/k3-am625-sk.dts >> +++ b/arch/arm64/boot/dts/ti/k3-am625-sk.dts >> @@ -366,6 +366,10 @@ &cpsw3g { >> pinctrl-names = "default"; >> pinctrl-0 = <&main_rgmii1_pins_default >> &main_rgmii2_pins_default>; >> + >> + cpts@3d000 { >> + ti,pps = <2 1>; >> + }; >> }; >> >> &cpsw_port1 { >> @@ -464,3 +468,19 @@ partition@3fc0000 { >> }; >> }; >> }; >> + >> +#define TS_OFFSET(pa, val) (0x4+(pa)*4) (0x10000 | val) > > Should this go in ./include/dt-bindings/pinctrl/k3.h ? > That way every board DT file doesn't have to define it. > > The name should be made more platform specific. > e.g. K3_TS_OFFSET if it is the same for all K3 platforms. > If not then please add Platform name instead of K3. The offsets are board specific. If it is acceptable, I will add board specific macro for the TS_OFFSET definition in the ./include/dt-bindings/pinctrl/k3.h file. Please let me know. Regards, Siddharth.
