Tool/software: Linux
Hi All,
With AM57x series, I want to control McASP audio clocks using clock synthesizers.
For the purpose, I want to know the clocking between PTP (CPTS) and PRU.
Developing environment:
- Latest version of Linux TI SDK (RT-version)
Question:
- Can PRU access counters which has linear relation to hardware PTP (CPTS) ?
Purpose:
- Using GPI of PRU, detect the timing of FCLK edge of McASP. (T1)
- PRU send message to ARM Linux, ARM Linux also obtains hardware PTP time using PHC.
- I want to make relation between T1 and hardware PTP time to calculate time differences between PTP and audio.
Background:
- With AM355x platform, the clocks for PTP and PRU (IEP) have fixed linear relation. So, I can use PRU clock as the timestamp for FCLK edge.
e2e.ti.com/.../509531
- How about AM57x?
Both PTP / PRU have the option for their clocks. Are there any combination to make linear relation between both clocks?
Or if PTP can access PTP (CPTS) clock, it seems better.
- Accroding to the datasheet (spruhz7c.pdf), these clocks are the default.
PTP (CPTS): CM_COREAON (L3_ICLK) <- CLKOUT_M2 (GMAC_250M_CLK)
PRU: CLKOUTX2_M3 (ICSS_IEP_CLK)
With Figure 3-32. PRCM Module Clock Manager Overview, it is difficult to judge the linearity between provided clocks from PRCM.
Regards,
Tommy