mirror_ubuntu-kernels/drivers/net/ethernet/intel/igb
Jacob Keller 1060707e38 ptp: introduce helpers to adjust by scaled parts per million
Many drivers implement the .adjfreq or .adjfine PTP op function with the
same basic logic:

  1. Determine a base frequency value
  2. Multiply this by the abs() of the requested adjustment, then divide by
     the appropriate divisor (1 billion, or 65,536 billion).
  3. Add or subtract this difference from the base frequency to calculate a
     new adjustment.

A few drivers need the difference and direction rather than the combined
new increment value.

I recently converted the Intel drivers to .adjfine and the scaled parts per
million (65.536 parts per billion) logic. To avoid overflow with minimal
loss of precision, mul_u64_u64_div_u64 was used.

The basic logic used by all of these drivers is very similar, and leads to
a lot of duplicate code to perform the same task.

Rather than keep this duplicate code, introduce diff_by_scaled_ppm and
adjust_by_scaled_ppm. These helper functions calculate the difference or
adjustment necessary based on the scaled parts per million input.

The diff_by_scaled_ppm function returns true if the difference should be
subtracted, and false otherwise.

Update the Intel drivers to use the new helper functions. Other vendor
drivers will be converted to .adjfine and this helper function in the
following changes.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-31 11:14:16 +00:00
..
e1000_82575.c igb: remove unexpected word "the" 2022-06-30 10:43:18 -07:00
e1000_82575.h
e1000_defines.h igb: Remove duplicate defines 2022-06-09 10:05:31 -07:00
e1000_hw.h igb: Fix duplicate include guard 2021-03-19 08:47:46 -07:00
e1000_i210.c igb: remove never changed variable `ret_val' 2021-12-21 09:17:47 -08:00
e1000_i210.h
e1000_mac.c intel/igb:fix repeated words in comments 2022-06-30 11:02:36 -07:00
e1000_mac.h
e1000_mbx.c intel: clean up mismatched header comments 2021-03-23 11:34:02 -07:00
e1000_mbx.h
e1000_nvm.c ethernet/intel: Convert fallthrough code comments 2020-07-01 13:47:43 -07:00
e1000_nvm.h
e1000_phy.c igb: Fix fall-through warnings for Clang 2021-03-23 11:34:02 -07:00
e1000_phy.h
e1000_regs.h igb: Remove duplicate defines 2022-06-09 10:05:31 -07:00
igb_ethtool.c net: Remove the obsolte u64_stats_fetch_*_irq() users (drivers). 2022-10-28 20:13:54 -07:00
igb_hwmon.c igb: convert to use i2c_new_client_device() 2020-03-26 19:31:21 -07:00
igb_main.c net: Remove the obsolte u64_stats_fetch_*_irq() users (drivers). 2022-10-28 20:13:54 -07:00
igb_ptp.c ptp: introduce helpers to adjust by scaled parts per million 2022-10-31 11:14:16 +00:00
igb.h igb: Add lock to avoid data race 2022-08-18 11:03:26 -07:00
Makefile