RE: [PATCH] igb: add conditions for I210 to generate periodic clock output

[Brown, Aaron F]

> From: netdev-owner@xxxxxxxxxxxxxxx [netdev-owner@xxxxxxxxxxxxxxx] on behalf of Roland Hii [roland.king.guan.hii@xxxxxxxxx]
> Sent: Sunday, January 10, 2016 11:34 PM
> To: Kirsher, Jeffrey T
> Cc: intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] igb: add conditions for I210 to generate periodic clock output
> 
> In general case the maximum supported half cycle time of the synchronized
> output clock is 70msec. Slower half cycle time than 70msec can be
> programmed also as long as the output clock is synchronized to whole
> seconds, useful specifically for generating a 1Hz clock.
> 
> Permitted values for the clock half cycle time are: 125,000,000 decimal,
> 250,000,000 decimal and 500,000,000 decimal (equals to 125msec, 250msec
> and 500msec respectively).
> 
> Before this patch, only the half cycle time of less than or equal to 70msec
> uses the I210 clock output function. This patch adds additional conditions
> when half cycle time is equal to 125msec or 250msec or 500msec to use
> clock output function.
> 
> Under other conditions, interrupt driven target time output events method
> is still used to generate the desired clock output.
> 
> Signed-off-by: Roland Hii <roland.king.guan.hii@xxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/igb/igb_ptp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>