V4L/DVB (11913): cx231xx: TRY_FMT should not actually set anything

In the TRY_FMT handler the function get_scale() is called to find what the
scaler hardware will produce for a requested size.

The problem is that get_scale(struct cx231xx *dev, ..., unsigned int *vscale,
unsigned int *hscale) saves the calculated scale values into both the
pointer arguments and into dev's hscale and vscale fields.  TRY_FMT shouldn't
actually change anything in the device state.

The code to in get_scale() that writes to dev->[hv]scale can just be
deleted.  In all cases when dev's fields should be modified, get_scale()
was called with get_scale(dev, ..., &dev->hscale, &dev->vscale), so dev was
getting updated anyway.

This didn't actually cause a problem because nothing ever actually made use
of the hscale and vscale fields.  I changed cx231xx_resolution_set() to use
those fields rather than re-calculate them with a call to get_scale().

Updating [hv]scale in cx231xx_resolution_set() isn't necessary because
every call of cx231xx_resolution_set() was already preceded by a call to
get_scale() or setting the [hv]scale fields, so they will be always be
up-to-date w.r.t. width and height.

Removing the call to get_scale() from cx231xx_resolution_set() allowed
making get_scale() a static function, which is a good thing for something
with such a short name.  There is already another function with the same
name in the em28xx driver, but that one is static.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx231xx/cx231xx-avcore.c

@@ -1052,22 +1052,13 @@ int cx231xx_set_audio_decoder_input(struct cx231xx *dev,
 /* Set resolution of the video */
 int cx231xx_resolution_set(struct cx231xx *dev)
 {
-	int width, height;
-	u32 hscale, vscale;
-	int status = 0;
-
-	width = dev->width;
-	height = dev->height;
-
-	get_scale(dev, width, height, &hscale, &vscale);
-
 	/* set horzontal scale */
-	status = vid_blk_write_word(dev, HSCALE_CTRL, hscale);
+	int status = vid_blk_write_word(dev, HSCALE_CTRL, dev->hscale);
+	if (status)
+		return status;
 
 	/* set vertical scale */
-	status = vid_blk_write_word(dev, VSCALE_CTRL, vscale);
-
-	return status;
+	return vid_blk_write_word(dev, VSCALE_CTRL, dev->vscale);
 }
 
 /******************************************************************************

drivers/media/video/cx231xx/cx231xx-video.c

@@ -893,7 +893,7 @@ static int check_dev(struct cx231xx *dev)
 	return 0;
 }
 
-void get_scale(struct cx231xx *dev,
+static void get_scale(struct cx231xx *dev,
 		      unsigned int width, unsigned int height,
 		      unsigned int *hscale, unsigned int *vscale)
 {
@@ -907,10 +907,6 @@ void get_scale(struct cx231xx *dev,
 	*vscale = (((unsigned long)maxh) << 12) / height - 4096L;
 	if (*vscale >= 0x4000)
 		*vscale = 0x3fff;
-
-	dev->hscale = *hscale;
-	dev->vscale = *vscale;
-
 }
 
 /* ------------------------------------------------------------------

drivers/media/video/cx231xx/cx231xx.h

@@ -722,9 +722,6 @@ int cx231xx_set_video_input_mux(struct cx231xx *dev, u8 input);
 int cx231xx_set_decoder_video_input(struct cx231xx *dev, u8 pin_type, u8 input);
 int cx231xx_do_mode_ctrl_overrides(struct cx231xx *dev);
 int cx231xx_set_audio_input(struct cx231xx *dev, u8 input);
-void get_scale(struct cx231xx *dev,
-	       unsigned int width, unsigned int height,
-	       unsigned int *hscale, unsigned int *vscale);
 
 /* Provided by cx231xx-video.c */
 int cx231xx_register_extension(struct cx231xx_ops *dev);