For some PTP devices, they have the capability to loop back the periodic
output signal for debugging, such as the ptp_qoriq device. So add the
generic interfaces to set the periodic output signal loopback, rather
than each vendor having a different implementation.
Show how many channels support the periodic output signal loopback:
$ cat /sys/kernel/debug/ptp<N>/n_perout_loopback
Enable the loopback of the periodic output signal of channel X:
$ echo <X> 1 > /sys/kernel/debug/ptp<N>/perout_loopback
Disable the loopback of the periodic output signal of channel X:
$ echo <X> 0 > /sys/kernel/debug/ptp<N>/perout_loopback
Suggested-by: Andrew Lunn <and...@lunn.ch>
Signed-off-by: Wei Fang <wei.f...@nxp.com>
---
drivers/ptp/ptp_clock.c | 66 ++++++++++++++++++++++++++++++++
include/linux/ptp_clock_kernel.h | 10 +++++
2 files changed, 76 insertions(+)
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 5739a57958c7..e4a5658e82b3 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -248,6 +248,66 @@ static void ptp_aux_kworker(struct kthread_work *work)
kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
}
+static ssize_t ptp_n_perout_loopback_read(struct file *filep,
+ char __user *buffer,
+ size_t count, loff_t *pos)
+{
+ struct ptp_clock *ptp = filep->private_data;
+ char buf[12] = {};
+
+ snprintf(buf, sizeof(buf), "%d\n", ptp->info->n_per_lp);
+
+ return simple_read_from_buffer(buffer, count, pos, buf, strlen(buf));
+}
+
+static const struct file_operations ptp_n_perout_loopback_fops = {
+ .owner = THIS_MODULE,
+ .open = simple_open,
+ .read = ptp_n_perout_loopback_read,
+};
+
+static ssize_t ptp_perout_loopback_write(struct file *filep,
+ const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct ptp_clock *ptp = filep->private_data;
+ struct ptp_clock_info *ops = ptp->info;
+ int len, cnt, enable, err;
+ unsigned int index;
+ char buf[32] = {};
+
+ if (*ppos || !count)
+ return -EINVAL;
+
+ if (count >= sizeof(buf))
+ return -ENOSPC;
+
+ len = simple_write_to_buffer(buf, sizeof(buf) - 1,
+ ppos, buffer, count);
+ if (len < 0)
+ return len;
+
+ buf[len] = '\0';
+ cnt = sscanf(buf, "%u %d", &index, &enable);
+ if (cnt != 2)
+ return -EINVAL;
+
+ if (index >= ops->n_per_lp)
+ return -EINVAL;
+
+ err = ops->perout_loopback(ops, index, enable ? 1 : 0);
+ if (err)
+ return err;
+
+ return count;
+}
+
+static const struct file_operations ptp_perout_loopback_ops = {
+ .owner = THIS_MODULE,
+ .open = simple_open,
+ .write = ptp_perout_loopback_write,
+};
+
/* public interface */
struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
@@ -389,6 +449,12 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info
*info,
/* Debugfs initialization */
snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
+ if (info->n_per_lp > 0 && info->perout_loopback) {
+ debugfs_create_file("n_perout_loopback", 0400,
ptp->debugfs_root,
+ ptp, &ptp_n_perout_loopback_fops);
+ debugfs_create_file("perout_loopback", 0200, ptp->debugfs_root,
+ ptp, &ptp_perout_loopback_ops);
+ }
return ptp;
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 7dd7951b23d5..884364596dd3 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -67,6 +67,8 @@ struct ptp_system_timestamp {
* @n_ext_ts: The number of external time stamp channels.
* @n_per_out: The number of programmable periodic signals.
* @n_pins: The number of programmable pins.
+ * @n_per_lp: The number of channels that support loopback the periodic
+ * output signal.
* @pps: Indicates whether the clock supports a PPS callback.
*
* @supported_perout_flags: The set of flags the driver supports for the
@@ -175,6 +177,11 @@ struct ptp_system_timestamp {
* scheduling time (>=0) or negative value in case further
* scheduling is not required.
*
+ * @perout_loopback: Request driver to enable or disable the periodic output
+ * signal loopback.
+ * parameter index: index of the periodic output signal
channel.
+ * parameter on: caller passes one to enable or zero to
disable.
+ *
* Drivers should embed their ptp_clock_info within a private
* structure, obtaining a reference to it using container_of().
*
@@ -189,6 +196,7 @@ struct ptp_clock_info {
int n_ext_ts;
int n_per_out;
int n_pins;
+ int n_per_lp;
int pps;
unsigned int supported_perout_flags;
unsigned int supported_extts_flags;
@@ -213,6 +221,8 @@ struct ptp_clock_info {
int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
enum ptp_pin_function func, unsigned int chan);
long (*do_aux_work)(struct ptp_clock_info *ptp);
+ int (*perout_loopback)(struct ptp_clock_info *ptp, unsigned int index,
+ int on);
};
struct ptp_clock;
--
2.34.1
