ptp: update adjfreq callback description

commit 87f4d7c1d36f44b0822053b7e5dedc31fdd0ab99 upstream.

This patch updates the adjfreq callback description to include a note that the
delta in ppb is always relative to the base frequency, and not to the current
frequency of the hardware clock.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
CC: Richard Cochran <richard.cochran@gmail.com>
CC: John Stultz <john.stultz@linaro.org>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index dd2e44fba63e769ef6315d654e566f5b178193b1..9d709d18c3b13bd3b5ac24b1e92906024a25530e 100644 (file)
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -50,7 +50,8 @@ struct ptp_clock_request {
  * clock operations
  *
  * @adjfreq:  Adjusts the frequency of the hardware clock.
- *            parameter delta: Desired period change in parts per billion.
+ *            parameter delta: Desired frequency offset from nominal frequency
+ *            in parts per billion
  *
  * @adjtime:  Shifts the time of the hardware clock.
  *            parameter delta: Desired change in nanoseconds.