[Intel-wired-lan] [PATCH 2/5] ixgbe: fix PTP SDP pin setup on X540 hardware

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Jacob Keller
> Sent: Monday, April 8, 2019 4:52 PM
> To: Intel Wired LAN <intel-wired-lan at lists.osuosl.org>
> Subject: [Intel-wired-lan] [PATCH 2/5] ixgbe: fix PTP SDP pin setup on X540
> hardware
> 
> The function ixgbe_ptp_setup_sdp_X540 attempts to program a software
> defined pin, in order to generate a pulse-per-second output on SDP 0.
> 
> It does work to generate the output, but does not align the output on the full
> second. Additionally, it does not take into account the cyclecounter
> multiplier. This leads to somewhat confusing code which is likely to be
> incorrect if blindly copied to another hardware type.
> 
> Update this code to account for the cyclecounter multiplier, and to directly
> use timecounter_read.
> 
> This change ensures that the SDP output will align properly on a full second,
> and makes the intent of the calculations a bit more clear.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | 71 ++++++++++++--------
>  1 file changed, 42 insertions(+), 29 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers at intel.com>