ptp: clarify the clock_name sysfs attribute
There has been some confusion among PHC driver authors about the
intended purpose of the clock_name attribute. This patch expands the
documation in order to clarify how the clock_name field should be
understood.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/ABI/testing/sysfs-ptp b/Documentation/ABI/testing/sysfs-ptp
index d40d2b5..05aeedf 100644
--- a/Documentation/ABI/testing/sysfs-ptp
+++ b/Documentation/ABI/testing/sysfs-ptp
@@ -19,7 +19,11 @@
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the name of the PTP hardware clock
- as a human readable string.
+ as a human readable string. The purpose of this
+ attribute is to provide the user with a "friendly
+ name" and to help distinguish PHY based devices from
+ MAC based ones. The string does not necessarily have
+ to be any kind of unique id.
What: /sys/class/ptp/ptpN/max_adjustment
Date: September 2010
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 56c71b2..f2dc6d8 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -42,7 +42,9 @@
* struct ptp_clock_info - decribes a PTP hardware clock
*
* @owner: The clock driver should set to THIS_MODULE.
- * @name: A short name to identify the clock.
+ * @name: A short "friendly name" to identify the clock and to
+ * help distinguish PHY based devices from MAC based ones.
+ * The string is not meant to be a unique id.
* @max_adj: The maximum possible frequency adjustment, in parts per billon.
* @n_alarm: The number of programmable alarms.
* @n_ext_ts: The number of external time stamp channels.
