gianfar: fix fiper alignment after resetting the time

After resetting the time, the PPS signals on the FIPER output channels
are incorrectly offset from the clock time, as can be readily verified
by a looping back the FIPER to the external time stamp input.

Despite its name, setting the "Fiper Realignment Disable" bit seems to
fix the problem, at least on the P2020.

Also, following the example code from the Freescale BSP, it is not really
necessary to disable and re-enable the timer in order to reprogram the
FIPER. (The documentation is rather unclear on this point. It seems that
writing to the alarm register also disables the FIPER.)

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Cc: <stable@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/gianfar_ptp.c b/drivers/net/gianfar_ptp.c
index 1c97861596f03cbcdcfa1aa30daac23360f90f4e..f67b8aebc89c3d71fe30c41bd1dff1265a7c1fb1 100644 (file)
--- a/drivers/net/gianfar_ptp.c
+++ b/drivers/net/gianfar_ptp.c
@@ -193,14 +193,9 @@ static void set_alarm(struct etsects *etsects)
 /* Caller must hold etsects->lock. */
 static void set_fipers(struct etsects *etsects)
 {
-       u32 tmr_ctrl = gfar_read(&etsects->regs->tmr_ctrl);
-
-       gfar_write(&etsects->regs->tmr_ctrl,   tmr_ctrl & (~TE));
-       gfar_write(&etsects->regs->tmr_prsc,   etsects->tmr_prsc);
+       set_alarm(etsects);
        gfar_write(&etsects->regs->tmr_fiper1, etsects->tmr_fiper1);
        gfar_write(&etsects->regs->tmr_fiper2, etsects->tmr_fiper2);
-       set_alarm(etsects);
-       gfar_write(&etsects->regs->tmr_ctrl,   tmr_ctrl|TE);
 }
 
 /*
@@ -511,7 +506,7 @@ static int gianfar_ptp_probe(struct platform_device *dev)
        gfar_write(&etsects->regs->tmr_fiper1, etsects->tmr_fiper1);
        gfar_write(&etsects->regs->tmr_fiper2, etsects->tmr_fiper2);
        set_alarm(etsects);
-       gfar_write(&etsects->regs->tmr_ctrl,   tmr_ctrl|FS|RTPE|TE);
+       gfar_write(&etsects->regs->tmr_ctrl,   tmr_ctrl|FS|RTPE|TE|FRD);
 
        spin_unlock_irqrestore(&etsects->lock, flags);