ptp: mlx4: convert to .adjfine and adjust_by_scaled_ppm

The mlx4 implementation of .adjfreq is implemented in terms of a
straight forward "base * ppb / 1 billion" calculation.

Convert this driver to .adjfine and use adjust_by_scaled_ppm to perform the
calculation.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Cc: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 0247885..98b5ffb 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -111,34 +111,27 @@ void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
 }
 
 /**
- * mlx4_en_phc_adjfreq - adjust the frequency of the hardware clock
+ * mlx4_en_phc_adjfine - adjust the frequency of the hardware clock
  * @ptp: ptp clock structure
- * @delta: Desired frequency change in parts per billion
+ * @scaled_ppm: Desired frequency change in scaled parts per million
  *
- * Adjust the frequency of the PHC cycle counter by the indicated delta from
- * the base frequency.
+ * Adjust the frequency of the PHC cycle counter by the indicated scaled_ppm
+ * from the base frequency.
+ *
+ * Scaled parts per million is ppm with a 16-bit binary fractional field.
  **/
-static int mlx4_en_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
+static int mlx4_en_phc_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
-       u64 adj;
-       u32 diff, mult;
-       int neg_adj = 0;
+       u32 mult;
        unsigned long flags;
        struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
                                                ptp_clock_info);
 
-       if (delta < 0) {
-               neg_adj = 1;
-               delta = -delta;
-       }
-       mult = mdev->nominal_c_mult;
-       adj = mult;
-       adj *= delta;
-       diff = div_u64(adj, 1000000000ULL);
+       mult = (u32)adjust_by_scaled_ppm(mdev->nominal_c_mult, scaled_ppm);
 
        write_seqlock_irqsave(&mdev->clock_lock, flags);
        timecounter_read(&mdev->clock);
-       mdev->cycles.mult = neg_adj ? mult - diff : mult + diff;
+       mdev->cycles.mult = mult;
        write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 
        return 0;
@@ -237,7 +230,7 @@ static const struct ptp_clock_info mlx4_en_ptp_clock_info = {
        .n_per_out      = 0,
        .n_pins         = 0,
        .pps            = 0,
-       .adjfreq        = mlx4_en_phc_adjfreq,
+       .adjfine        = mlx4_en_phc_adjfine,
        .adjtime        = mlx4_en_phc_adjtime,
        .gettime64      = mlx4_en_phc_gettime,
        .settime64      = mlx4_en_phc_settime,