From bc443c253fcdd2636e2a29fde3f749d39d479cf0 Mon Sep 17 00:00:00 2001 From: Ivan Vecera Date: Mon, 26 Jan 2026 17:22:51 +0100 Subject: dpll: expose fractional frequency offset in ppt Currently, the dpll subsystem exports the fractional frequency offset (FFO) in parts per million (ppm). This granularity is insufficient for high-precision synchronization scenarios which often require parts per trillion (ppt) resolution. Add a new netlink attribute DPLL_A_PIN_FRACTIONAL_FREQUENCY_OFFSET_PPT to expose the FFO in ppt. Update the dpll netlink core to expect the driver-provided FFO value to be in ppt. To maintain backward compatibility with existing userspace tools, populate the legacy DPLL_A_PIN_FRACTIONAL_FREQUENCY_OFFSET attribute by dividing the new ppt value by 1,000,000. Update the zl3073x and mlx5 drivers to provide the FFO value in ppt: - zl3073x: adjust the fixed-point calculation to produce ppt (10^12) instead of ppm (10^6). - mlx5: scale the existing ppm value by 1,000,000. Signed-off-by: Ivan Vecera Reviewed-by: Arkadiusz Kubalewski Reviewed-by: Jiri Pirko Link: https://patch.msgid.link/20260126162253.27890-1-ivecera@redhat.com Signed-off-by: Jakub Kicinski --- include/uapi/linux/dpll.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/uapi/linux/dpll.h b/include/uapi/linux/dpll.h index b7ff9c44f9aa..de0005f28e5c 100644 --- a/include/uapi/linux/dpll.h +++ b/include/uapi/linux/dpll.h @@ -253,6 +253,7 @@ enum dpll_a_pin { DPLL_A_PIN_ESYNC_PULSE, DPLL_A_PIN_REFERENCE_SYNC, DPLL_A_PIN_PHASE_ADJUST_GRAN, + DPLL_A_PIN_FRACTIONAL_FREQUENCY_OFFSET_PPT, __DPLL_A_PIN_MAX, DPLL_A_PIN_MAX = (__DPLL_A_PIN_MAX - 1) -- cgit v1.2.3