media: staging/imx: remove confusing IS_ERR_OR_NULL usage

While looking at a compiler warning, I noticed the use of
IS_ERR_OR_NULL, which is generally a sign of a bad API design
and should be avoided.

In this driver, this is fairly easy, we can simply stop storing
error pointers in persistent structures, and change the two
functions that might return either a NULL pointer or an error
code to consistently return error pointers when failing.

of_parse_subdev() now separates the error code and the pointer
it looks up, to clarify the interface. There are two cases
where this function originally returns 'NULL', and I have
changed that to '0' for success to keep the current behavior,
though returning an error would also make sense there.

Fixes: e130291212df ("[media] media: Add i.MX media core driver")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Tested-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 18 insertions, 12 deletions

diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index f2d64d1eeff8..552a030f3232 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -122,11 +122,11 @@ static inline struct csi_priv *sd_to_dev(struct v4l2_subdev *sdev)
 
 static void csi_idmac_put_ipu_resources(struct csi_priv *priv)
 {
-	if (!IS_ERR_OR_NULL(priv->idmac_ch))
+	if (priv->idmac_ch)
 		ipu_idmac_put(priv->idmac_ch);
 	priv->idmac_ch = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->smfc))
+	if (priv->smfc)
 		ipu_smfc_put(priv->smfc);
 	priv->smfc = NULL;
 }
@@ -134,23 +134,27 @@ static void csi_idmac_put_ipu_resources(struct csi_priv *priv)
 static int csi_idmac_get_ipu_resources(struct csi_priv *priv)
 {
 	int ch_num, ret;
+	struct ipu_smfc *smfc;
+	struct ipuv3_channel *idmac_ch;
 
 	ch_num = IPUV3_CHANNEL_CSI0 + priv->smfc_id;
 
-	priv->smfc = ipu_smfc_get(priv->ipu, ch_num);
-	if (IS_ERR(priv->smfc)) {
+	smfc = ipu_smfc_get(priv->ipu, ch_num);
+	if (IS_ERR(smfc)) {
 		v4l2_err(&priv->sd, "failed to get SMFC\n");
-		ret = PTR_ERR(priv->smfc);
+		ret = PTR_ERR(smfc);
 		goto out;
 	}
+	priv->smfc = smfc;
 
-	priv->idmac_ch = ipu_idmac_get(priv->ipu, ch_num);
-	if (IS_ERR(priv->idmac_ch)) {
+	idmac_ch = ipu_idmac_get(priv->ipu, ch_num);
+	if (IS_ERR(idmac_ch)) {
 		v4l2_err(&priv->sd, "could not get IDMAC channel %u\n",
 			 ch_num);
-		ret = PTR_ERR(priv->idmac_ch);
+		ret = PTR_ERR(idmac_ch);
 		goto out;
 	}
+	priv->idmac_ch = idmac_ch;
 
 	return 0;
 out:
@@ -1585,6 +1589,7 @@ static int csi_unsubscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
 static int csi_registered(struct v4l2_subdev *sd)
 {
 	struct csi_priv *priv = v4l2_get_subdevdata(sd);
+	struct ipu_csi *csi;
 	int i, ret;
 	u32 code;
 
@@ -1592,11 +1597,12 @@ static int csi_registered(struct v4l2_subdev *sd)
 	priv->md = dev_get_drvdata(sd->v4l2_dev->dev);
 
 	/* get handle to IPU CSI */
-	priv->csi = ipu_csi_get(priv->ipu, priv->csi_id);
-	if (IS_ERR(priv->csi)) {
+	csi = ipu_csi_get(priv->ipu, priv->csi_id);
+	if (IS_ERR(csi)) {
 		v4l2_err(&priv->sd, "failed to get CSI%d\n", priv->csi_id);
-		return PTR_ERR(priv->csi);
+		return PTR_ERR(csi);
 	}
+	priv->csi = csi;
 
 	for (i = 0; i < CSI_NUM_PADS; i++) {
 		priv->pad[i].flags = (i == CSI_SINK_PAD) ?
@@ -1665,7 +1671,7 @@ static void csi_unregistered(struct v4l2_subdev *sd)
 	if (priv->fim)
 		imx_media_fim_free(priv->fim);
 
-	if (!IS_ERR_OR_NULL(priv->csi))
+	if (priv->csi)
 		ipu_csi_put(priv->csi);
 }