From: H Hartley Sweeten <hsweeten@visionengravers.com>
Date: Thu, 17 Apr 2014 17:08:04 +0000 (-0700)
Subject: staging: comedi: ni_labpc: clarify the cmd->start_arg validation
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c55881686302a5e7f19b82f0a163beec2cc314c3;p=deliverable%2Flinux.git

staging: comedi: ni_labpc: clarify the cmd->start_arg validation

This driver supports cmd->start_src sources of TRIG_NOW and TRIG_EXT.
Refactor the (*do_cmdtest) to clarify the trivial validation of the
cmd->start_arg.

This also fixes a bug, the cmd->start_src has the trigger not the
cmd->start_arg.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
index f80ca3278314..fc9d31420956 100644
--- a/drivers/staging/comedi/drivers/ni_labpc.c
+++ b/drivers/staging/comedi/drivers/ni_labpc.c
@@ -649,8 +649,14 @@ static int labpc_ai_cmdtest(struct comedi_device *dev,
 
 	/* Step 3: check if arguments are trivially valid */
 
-	if (cmd->start_arg == TRIG_NOW)
+	switch (cmd->start_src) {
+	case TRIG_NOW:
 		err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
+		break;
+	case TRIG_EXT:
+		/* start_arg value is ignored */
+		break;
+	}
 
 	if (!cmd->chanlist_len)
 		err |= -EINVAL;