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Date: Tue, 14 Mar 2023 17:52:26 -0700
From: Alexander Komrakov <alexander.komrakov@...adcom.com>
To: linux-kernel@...r.kernel.org
Cc: giometti@...eenne.com, gregkh@...uxfoundation.org,
Alexander Komrakov <alexander.komrakov@...adcom.com>
Subject: [PATCH v3] pps: Add elapsed realtime timestamping
Some applications like Android needs elapsed realtime timestamping
to PPS pulse for its clock management. Add sysfs node for this.
Signed-off-by: Alexander Komrakov <alexander.komrakov@...adcom.com>
---
Changes in v3:
- Remove "staging",wrap changelog text at 72 columns and remove sysfs_emit()
- .gittconfg updated, clock_gettime removed, trailing whitespaces remvoved
- COONFIG_ELAPSED_REALTIME_PPS added to enable elapsed assert/clear sysfs
Documentation/ABI/testing/sysfs-pps | 27 ++++++++++++++++++
drivers/pps/Makefile | 4 +++
drivers/pps/kapi.c | 24 ++++++++++++++--
drivers/pps/sysfs.c | 44 +++++++++++++++++++++++++++--
include/linux/pps_kernel.h | 2 ++
5 files changed, 96 insertions(+), 5 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-pps b/Documentation/ABI/testing/sysfs-pps
index 25028c7bc37d..031ec89e1ed6 100644
--- a/Documentation/ABI/testing/sysfs-pps
+++ b/Documentation/ABI/testing/sysfs-pps
@@ -1,3 +1,30 @@
+What: /sys/class/pps/pps0/assert_elapsed
+Date: October 2021
+Contact: Alexander Komrakov <alexander.komrakov@...adcom.com>
+Description:
+ The /sys/class/pps/ppsX/assert_elapsed file reports the
+ elapsed real-time assert events and the elapsed
+ real-time assert sequence number of the X-th source
+ in the form:
+
+ <secs>.<nsec>#<sequence>
+
+ If the source has no elapsed real-time assert events
+ the content of this file is empty.
+
+What: /sys/class/pps/ppsX/clear_elapsed
+Date: October 2021
+Contact: Alexander Komrakov <alexander.komrakov@...adcom.com>
+Description:
+ The /sys/class/pps/ppsX/clear_elapsed file reports the elapsed
+ real-time clear events and the elapsed real-time clear
+ sequence number of the X-th source in the form:
+
+ <secs>.<nsec>#<sequence>
+
+ If the source has no elapsed real-time clear events the
+ content of this file is empty.
+
What: /sys/class/pps/
Date: February 2008
Contact: Rodolfo Giometti <giometti@...ux.it>
diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile
index ceaf65cc1f1d..443501310445 100644
--- a/drivers/pps/Makefile
+++ b/drivers/pps/Makefile
@@ -8,4 +8,8 @@ pps_core-$(CONFIG_NTP_PPS) += kc.o
obj-$(CONFIG_PPS) := pps_core.o
obj-y += clients/ generators/
+ifeq ($(CONFIG_ELAPSED_REALTIME_PPS),y)
+EXTRA_CFLAGS += -DENABLE_ELAPSED_REALTIME_PPS
+endif
+
ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index d9d566f70ed1..69b432873ce7 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -23,6 +23,7 @@
/*
* Local functions
*/
+ #define NANOSEC_PER_SEC 1000000000 /* 10^9 */
static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
{
@@ -162,11 +163,20 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
unsigned long flags;
int captured = 0;
struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 };
+ struct pps_ktime ts_real_elapsed = { .sec = 0, .nsec = 0, .flags = 0 };
+ struct timespec64 ts64 = { .tv_sec = 0, .tv_nsec = 0 };
/* check event type */
BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0);
+ /* Calculate the monotonic clock from the timespec clock and stores the result in pps_ktime format
+ ktime_get_boottime_ts64() : because elapsed realtime includes time spent in sleep */
+ ktime_get_boottime_ts64(&ts64);
+ timespec_to_pps_ktime(&ts_real_elapsed,ts64);
- dev_dbg(pps->dev, "PPS event at %lld.%09ld\n",
+ dev_dbg(pps->dev, "PPS event (monotonic) at %lld.%09d\n",
+ (s64)ts_real_elapsed.sec, ts_real_elapsed.nsec);
+
+ dev_dbg(pps->dev, "PPS event (timestamp) at %lld.%09ld\n",
(s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
timespec_to_pps_ktime(&ts_real, ts->ts_real);
@@ -181,11 +191,15 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
pps->current_mode = pps->params.mode;
if (event & pps->params.mode & PPS_CAPTUREASSERT) {
/* We have to add an offset? */
- if (pps->params.mode & PPS_OFFSETASSERT)
+ if (pps->params.mode & PPS_OFFSETASSERT) {
+ pps_add_offset(&ts_real_elapsed,
+ &pps->params.assert_off_tu);
pps_add_offset(&ts_real,
&pps->params.assert_off_tu);
+ }
/* Save the time stamp */
+ pps->assert_elapsed_tu = ts_real_elapsed;
pps->assert_tu = ts_real;
pps->assert_sequence++;
dev_dbg(pps->dev, "capture assert seq #%u\n",
@@ -195,11 +209,15 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
}
if (event & pps->params.mode & PPS_CAPTURECLEAR) {
/* We have to add an offset? */
- if (pps->params.mode & PPS_OFFSETCLEAR)
+ if (pps->params.mode & PPS_OFFSETCLEAR) {
+ pps_add_offset(&ts_real_elapsed,
+ &pps->params.clear_off_tu);
pps_add_offset(&ts_real,
&pps->params.clear_off_tu);
+ }
/* Save the time stamp */
+ pps->clear_elapsed_tu = ts_real_elapsed;
pps->clear_tu = ts_real;
pps->clear_sequence++;
dev_dbg(pps->dev, "capture clear seq #%u\n",
diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
index 134bc33f6ad0..9e100e287ba7 100644
--- a/drivers/pps/sysfs.c
+++ b/drivers/pps/sysfs.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/string.h>
#include <linux/pps_kernel.h>
+#include <linux/sysfs.h>
/*
* Attribute functions
@@ -24,11 +25,28 @@ static ssize_t assert_show(struct device *dev, struct device_attribute *attr,
return 0;
return sprintf(buf, "%lld.%09d#%d\n",
- (long long) pps->assert_tu.sec, pps->assert_tu.nsec,
- pps->assert_sequence);
+ (long long) pps->assert_tu.sec, pps->assert_tu.nsec,
+ pps->assert_sequence);
}
static DEVICE_ATTR_RO(assert);
+#ifdef ENABLE_ELAPSED_REALTIME_PPS
+static ssize_t assert_elapsed_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct pps_device *pps = dev_get_drvdata(dev);
+
+ if (!(pps->info.mode & PPS_CAPTUREASSERT))
+ return 0;
+
+ return sprintf(buf, "%lld.%09d#%d\n",
+ (long long) pps->assert_elapsed_tu.sec,
+ pps->assert_elapsed_tu.nsec,
+ pps->assert_sequence);
+}
+static DEVICE_ATTR_RO(assert_elapsed);
+#endif
+
static ssize_t clear_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -43,6 +61,24 @@ static ssize_t clear_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(clear);
+#ifdef ENABLE_ELAPSED_REALTIME_PPS
+static ssize_t clear_elapsed_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pps_device *pps = dev_get_drvdata(dev);
+
+ if (!(pps->info.mode & PPS_CAPTURECLEAR))
+ return 0;
+
+ return sprintf(buf, "%lld.%09d#%d\n",
+ (long long) pps->clear_elapsed_tu.sec,
+ pps->clear_elapsed_tu.nsec,
+ pps->clear_sequence);
+}
+static DEVICE_ATTR_RO(clear_elapsed);
+#endif
+
static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -82,6 +118,10 @@ static DEVICE_ATTR_RO(path);
static struct attribute *pps_attrs[] = {
&dev_attr_assert.attr,
&dev_attr_clear.attr,
+#ifdef ENABLE_ELAPSED_REALTIME_PPS
+ &dev_attr_assert_elapsed.attr,
+ &dev_attr_clear_elapsed.attr,
+#endif
&dev_attr_mode.attr,
&dev_attr_echo.attr,
&dev_attr_name.attr,
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 78c8ac4951b5..1fecaaf4c8b9 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -47,6 +47,8 @@ struct pps_device {
__u32 assert_sequence; /* PPS assert event seq # */
__u32 clear_sequence; /* PPS clear event seq # */
+ struct pps_ktime assert_elapsed_tu; /* PPS elapsed rt assert seq # */
+ struct pps_ktime clear_elapsed_tu; /* PPS elapsed rt clear event seq */
struct pps_ktime assert_tu;
struct pps_ktime clear_tu;
int current_mode; /* PPS mode at event time */
--
2.25.1
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