On 16/01/2023 09:12, Siddharth Vadapalli wrote: > 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. If it is board specific then it should remain in the board file. cheers, -roger
