[net-next 09/15] igc: Remove references to SYSTIMR register

[Tony Nguyen]

From: Vinicius Costa Gomes <vinicius.go...@intel.com>

In i225, it's no longer necessary to use the SYSTIMR register to
latch the timer value, the timestamp is latched when SYSTIML is read.

Signed-off-by: Vinicius Costa Gomes <vinicius.go...@intel.com>
Tested-by: Aaron Brown <aaron.f.br...@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.ngu...@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_ptp.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c 
b/drivers/net/ethernet/intel/igc/igc_ptp.c
index 61852c99815d..0300b45b36e2 100644
--- a/drivers/net/ethernet/intel/igc/igc_ptp.c
+++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
@@ -22,11 +22,7 @@ static void igc_ptp_read_i225(struct igc_adapter *adapter,
        struct igc_hw *hw = &adapter->hw;
        u32 sec, nsec;
 
-       /* The timestamp latches on lowest register read. For I210/I211, the
-        * lowest register is SYSTIMR. Since we only need to provide nanosecond
-        * resolution, we can ignore it.
-        */
-       rd32(IGC_SYSTIMR);
+       /* The timestamp is latched when SYSTIML is read. */
        nsec = rd32(IGC_SYSTIML);
        sec = rd32(IGC_SYSTIMH);
 
@@ -39,9 +35,6 @@ static void igc_ptp_write_i225(struct igc_adapter *adapter,
 {
        struct igc_hw *hw = &adapter->hw;
 
-       /* Writing the SYSTIMR register is not necessary as it only
-        * provides sub-nanosecond resolution.
-        */
        wr32(IGC_SYSTIML, ts->tv_nsec);
        wr32(IGC_SYSTIMH, ts->tv_sec);
 }
@@ -102,10 +95,9 @@ static int igc_ptp_gettimex64_i225(struct ptp_clock_info 
*ptp,
        spin_lock_irqsave(&igc->tmreg_lock, flags);
 
        ptp_read_system_prets(sts);
-       rd32(IGC_SYSTIMR);
-       ptp_read_system_postts(sts);
        ts->tv_nsec = rd32(IGC_SYSTIML);
        ts->tv_sec = rd32(IGC_SYSTIMH);
+       ptp_read_system_postts(sts);
 
        spin_unlock_irqrestore(&igc->tmreg_lock, flags);
 
-- 
2.26.2