[PATCH net-next v2 00/11] net: dsa: microchip: PTP support for KSZ956x

[Christian Eggers]

There is only little documentation for PTP available on the data sheet
[1] (more or less only the register reference). Questions to the
Microchip support were seldom answered comprehensively or in reasonable
time. So this is more or less the result of reverse engineering.

[1]
http://ww1.microchip.com/downloads/en/DeviceDoc/KSZ9563R-Data-Sheet-DS00002419D.pdf

Changes from RFC --> v2
------------------------
I think that all open questions regarding the RFC version could be solved.
dts: referenced to dsa.yaml
dts: changed node name to "switch" in example
dts: changed "ports" subnode to "ethernet-ports"
ksz_common: support "ethernet-ports" subnode
tag_ksz: fix usage of correction field (32 bit ns + 16 bit sub-ns)
tag_ksz: use cached PTP header from device's .port_txtstamp function
tag_ksz: refactored ksz9477_tstamp_to_clock()
tag_ksz: pdelay_req: only subtract 2 bit seconds from the correction field
tag_ksz: pdelay_resp: don't move (negative) correction to the egress tail tag
ptp_classify: add ptp_onestep_p2p_move_t2_to_correction helper
ksz9477_ptp: removed E2E support (as suggested by Vladimir)
ksz9477_ptp: removed master/slave sysfs attributes (nacked by Richard)
ksz9477_ptp: refactored ksz9477_ptp_port_txtstamp
ksz9477_ptp: removed "pulse" attribute
kconfig: depend on PTP_1588_CLOCK (instead of "imply")