[PATCH net-next] macb: Add hardware PTP support.

[davem@davemloft.net (David Miller)]

From: Rafal Ozieblo <rafalo@cadence.com>
Date: Mon, 3 Apr 2017 14:10:15 +0100

> This patch is based on original Harini's patch and Andrei's patch,
> implemented in aseparate file to ease the review/maintanance
> and integration with other platforms.
> 
> In case that macb is compiled as a module, it has been renamed to
> cadence-macb.ko to avoid naming confusion in Makefile.
> 
> This driver does support GEM-GXL:
> - Enable HW time stamp
> - Register ptp clock framework
> - Initialize PTP related registers
> - Updated dma buffer descriptor read/write mechanism
> - HW time stamp on the PTP Ethernet packets are received using the
>   SO_TIMESTAMPING API. Where timers are obtained from the dma buffer
>   descriptors
> - Added tsu_clk to device tree
> 
> Note: Patch on net-next, on April 3rd.
> Signed-off-by: Rafal Ozieblo <rafalo@cadence.com>

This patch does too many things at one time.  Each entry in that list
of changes above should be a separate change, all posted together as
a group as a proper patch series.

Thank you.