pps: default echo function

A default echo function has been provided so it is no longer an error when
you specify PPS_ECHOASSERT or PPS_ECHOCLEAR without an explicit echo
function. This allows some code re-use and also makes it easier to write
client drivers since the default echo function does not normally need to
change.

Signed-off-by: James Nuss <[e-mail]>
Reviewed-by: Ben Gardiner <[e-mail]>
Acked-by: Rodolfo Giometti <[e-mail]>
Cc: Ricardo Martins <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Igor Plyatov <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/pps/clients/pps-ktimer.c

···
 }
 
 /*
- * The echo function
- */
-
-static void pps_ktimer_echo(struct pps_device *pps, int event, void *data)
-{
-	dev_info(pps->dev, "echo %s %s\n",
-		event & PPS_CAPTUREASSERT ? "assert" : "",
-		event & PPS_CAPTURECLEAR ? "clear" : "");
-}
-
-/*
  * The PPS info struct
  */
 
···
 	.mode		= PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
 			  PPS_ECHOASSERT |
 			  PPS_CANWAIT | PPS_TSFMT_TSPEC,
-	.echo		= pps_ktimer_echo,
 	.owner		= THIS_MODULE,
 };
 

drivers/pps/clients/pps_parport.c

···
 	return;
 }
 
-/* the PPS echo function */
-static void pps_echo(struct pps_device *pps, int event, void *data)
-{
-	dev_info(pps->dev, "echo %s %s\n",
-		event & PPS_CAPTUREASSERT ? "assert" : "",
-		event & PPS_CAPTURECLEAR ? "clear" : "");
-}
-
 static void parport_attach(struct parport *port)
 {
 	struct pps_client_pp *device;
···
 				  PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
 				  PPS_ECHOASSERT | PPS_ECHOCLEAR | \
 				  PPS_CANWAIT | PPS_TSFMT_TSPEC,
-		.echo		= pps_echo,
 		.owner		= THIS_MODULE,
 		.dev		= NULL
 	};

drivers/pps/kapi.c

···
 	ts->sec += offset->sec;
 }
 
+static void pps_echo_client_default(struct pps_device *pps, int event,
+		void *data)
+{
+	dev_info(pps->dev, "echo %s %s\n",
+		event & PPS_CAPTUREASSERT ? "assert" : "",
+		event & PPS_CAPTURECLEAR ? "clear" : "");
+}
+
 /*
  * Exported functions
  */
···
 		err = -EINVAL;
 		goto pps_register_source_exit;
 	}
-	if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
-			info->echo == NULL) {
-		pr_err("%s: echo function is not defined\n",
-					info->name);
-		err = -EINVAL;
-		goto pps_register_source_exit;
-	}
 	if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
 		pr_err("%s: unspecified time format\n",
 					info->name);
···
 	pps->params.api_version = PPS_API_VERS;
 	pps->params.mode = default_params;
 	pps->info = *info;
+
+	/* check for default echo function */
+	if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) &&
+			pps->info.echo == NULL)
+		pps->info.echo = pps_echo_client_default;
 
 	init_waitqueue_head(&pps->queue);
 	spin_lock_init(&pps->lock);