staging: comedi: use unsigned samples for comedi_buf_put()/get()

Sample values in comedi are generally represented as unsigned values.
`comedi_buf_put()` and `comedi_buf_get()` use a `short` to hold the
16-bit data value being transferred to or from the comedi buffer.
Change them to use `unsigned short` for consistency.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_buf.c

@@ -344,7 +344,7 @@ unsigned int comedi_buf_read_free(struct comedi_async *async,
 }
 EXPORT_SYMBOL_GPL(comedi_buf_read_free);
 
-int comedi_buf_put(struct comedi_async *async, short x)
+int comedi_buf_put(struct comedi_async *async, unsigned short x)
 {
 	unsigned int n = __comedi_buf_write_alloc(async, sizeof(short), 1);
 
@@ -352,20 +352,20 @@ int comedi_buf_put(struct comedi_async *async, short x)
 		async->events |= COMEDI_CB_ERROR;
 		return 0;
 	}
-	*(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
+	*(unsigned short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 	comedi_buf_write_free(async, sizeof(short));
 	return 1;
 }
 EXPORT_SYMBOL_GPL(comedi_buf_put);
 
-int comedi_buf_get(struct comedi_async *async, short *x)
+int comedi_buf_get(struct comedi_async *async, unsigned short *x)
 {
 	unsigned int n = comedi_buf_read_n_available(async);
 
 	if (n < sizeof(short))
 		return 0;
 	comedi_buf_read_alloc(async, sizeof(short));
-	*x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
+	*x = *(unsigned short *)(async->prealloc_buf + async->buf_read_ptr);
 	comedi_buf_read_free(async, sizeof(short));
 	return 1;
 }

drivers/staging/comedi/comedidev.h

@@ -346,8 +346,8 @@ unsigned int comedi_buf_read_n_available(struct comedi_async *);
 unsigned int comedi_buf_read_alloc(struct comedi_async *, unsigned int);
 unsigned int comedi_buf_read_free(struct comedi_async *, unsigned int);
 
-int comedi_buf_put(struct comedi_async *, short);
-int comedi_buf_get(struct comedi_async *, short *);
+int comedi_buf_put(struct comedi_async *, unsigned short);
+int comedi_buf_get(struct comedi_async *, unsigned short *);
 
 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 			  const void *source, unsigned int num_bytes);