From 148e34fd33d53740642db523724226de14ee5281 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@mev.co.uk>
Date: Tue, 23 Feb 2021 14:30:50 +0000
Subject: [PATCH] staging: comedi: pcl818: Fix endian problem for AI command data
Git-commit: 148e34fd33d53740642db523724226de14ee5281
Patch-mainline: v5.12-rc3
References: git-fixes

The analog input subdevice supports Comedi asynchronous commands that
use Comedi's 16-bit sample format.  However, the call to
`comedi_buf_write_samples()` is passing the address of a 32-bit integer
parameter.  On bigendian machines, this will copy 2 bytes from the wrong
end of the 32-bit value.  Fix it by changing the type of the parameter
holding the sample value to `unsigned short`.

[note: the bug was introduced in commit edf4537bcbf5 ("staging: comedi:
Pcl818: use comedi_buf_write_samples()") but the patch applies better to
commit d615416de615 ("staging: comedi: pcl818: introduce
pcl818_ai_write_sample()").]

Fixes: d615416de615 ("staging: comedi: pcl818: introduce pcl818_ai_write_sample()")
Cc: <stable@vger.kernel.org> # 4.0+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-10-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/comedi/drivers/pcl818.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c
index 63e3011158f2..f4b4a686c710 100644
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -423,7 +423,7 @@ static int pcl818_ai_eoc(struct comedi_device *dev,
 
 static bool pcl818_ai_write_sample(struct comedi_device *dev,
 				   struct comedi_subdevice *s,
-				   unsigned int chan, unsigned int val)
+				   unsigned int chan, unsigned short val)
 {
 	struct pcl818_private *devpriv = dev->private;
 	struct comedi_cmd *cmd = &s->async->cmd;
-- 
2.26.2