imx8: csi: Implement proper subdev access

Until now, the device searched for the subdev (sensor dev) using the
device name. That was a hack and required a hard-coded name of the
device in the common code.

This commit fixes it and makes it look for the proper subdevice using
the media pads layer.

(cherry picked from commit 9958f930c175cf8948278c85f4006870bebeebbb)

Conflicts:
	drivers/media/platform/imx8/mxc-isi-cap.c
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
(cherry picked from commit ce78564e48dca603c014786221b509bdc009e594)
(cherry picked from commit bfdbb433972d838171ed4a8b8c51e4fd3cc8d6cf)
(cherry picked from commit 839df9bc9ad0cf2aecc20302f767e9a7a938b8bb)

1 files changed, 75 insertions, 15 deletions

diff --git a/drivers/media/platform/imx8/mxc-isi-cap.c b/drivers/media/platform/imx8/mxc-isi-cap.c
index f5bde4e88605..eab0864b7a03 100644
--- a/drivers/media/platform/imx8/mxc-isi-cap.c
+++ b/drivers/media/platform/imx8/mxc-isi-cap.c
@@ -860,6 +860,65 @@ static int mxc_isi_cap_try_fmt_mplane(struct file *file, void *fh,
 	return 0;
 }
 
+static struct media_pad *subdev_get_remote_source_pad(struct v4l2_subdev *subdev)
+{
+	struct media_pad *sink_pad, *source_pad;
+	int i;
+
+	while (1) {
+		source_pad = NULL;
+		for (i = 0; i < subdev->entity.num_pads; i++) {
+			sink_pad = &subdev->entity.pads[i];
+
+			if (sink_pad->flags & MEDIA_PAD_FL_SINK) {
+				source_pad = media_entity_remote_pad(sink_pad);
+				if (source_pad)
+					break;
+			}
+		}
+		/* return first pad point in the loop  */
+		return source_pad;
+	}
+
+	return NULL;
+}
+
+static struct v4l2_subdev *mxc_isi_get_sensor_subdev(struct v4l2_subdev *subdev)
+{
+	struct media_pad *source_pad;
+	struct v4l2_subdev *sd;
+
+	/* Firstly find mipi interface, so remote source for the isi */
+	source_pad = subdev_get_remote_source_pad(subdev);
+	if (source_pad == NULL) {
+		v4l2_err(subdev->v4l2_dev, "%s, No remote pad found!\n", __func__);
+		return NULL;
+	}
+
+	/* Get remote source pad subdev */
+	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	if (sd == NULL) {
+		v4l2_err(subdev->v4l2_dev, "Can't find subdev\n");
+		return NULL;
+	}
+
+	/* Then find the actual sensor which should be on the pad of mipi */
+	source_pad = subdev_get_remote_source_pad(sd);
+	if (source_pad == NULL) {
+		v4l2_err(subdev->v4l2_dev, "%s, No remote pad found!\n", __func__);
+		return NULL;
+	}
+
+	/* Get remote source pad subdev */
+	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	if (sd == NULL) {
+		v4l2_err(subdev->v4l2_dev, "Can't find subdev\n");
+		return NULL;
+	}
+
+	return sd;
+}
+
 /* Update input frame size and formate  */
 static int mxc_isi_source_fmt_init(struct mxc_isi_dev *mxc_isi)
 {
@@ -871,7 +930,7 @@ static int mxc_isi_source_fmt_init(struct mxc_isi_dev *mxc_isi)
 	int ret;
 
 	/* Get remote source pad */
-	source_pad = mxc_isi_get_remote_source_pad(mxc_isi);
+	source_pad = subdev_get_remote_source_pad(&mxc_isi->isi_cap.sd);
 	if (source_pad == NULL) {
 		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote pad found!\n", __func__);
 		return -EINVAL;
@@ -1143,6 +1202,7 @@ static int mxc_isi_cap_g_chip_ident(struct file *file, void *fb,
 	struct device_node *local, *remote, *endpoint;
 	struct mxc_isi_dev *mxc_isi = video_drvdata(file);
 	struct video_device *vdev = video_devdata(file);
+	struct v4l2_dbg_chip_ident ci;
 	struct v4l2_subdev *sd;
 	struct media_pad *source_pad;
 
@@ -1153,7 +1213,7 @@ static int mxc_isi_cap_g_chip_ident(struct file *file, void *fb,
 	}
 
 	/* Get remote source pad subdev */
-	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	sd = mxc_isi_get_sensor_subdev(&mxc_isi->isi_cap.sd);
 	if (sd == NULL) {
 		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote subdev found!\n", __func__);
 		return -EINVAL;
@@ -1179,9 +1239,14 @@ static int mxc_isi_cap_g_chip_ident(struct file *file, void *fb,
 		return -ENODEV;
 	}
 
-	sprintf(chip->match.name, "imx8_%s_%d", remote->name, vdev->num);
+	sprintf(chip->match.name, "%s-%d\n", sd->name, vdev->num);
 
-	return 0;
+	/* Just check if the callback of the sensor device returns success,
+	 * no need to actually identify the device since we're using the
+	 * pads to find it.
+	 */
+
+	return v4l2_subdev_call(sd, core, g_chip_ident, &ci);
 }
 
 static int mxc_isi_cap_g_parm(struct file *file, void *fh,
@@ -1198,7 +1263,7 @@ static int mxc_isi_cap_g_parm(struct file *file, void *fh,
 	}
 
 	/* Get remote source pad subdev */
-	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	sd = mxc_isi_get_sensor_subdev(&mxc_isi->isi_cap.sd);
 	if (sd == NULL) {
 		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote subdev found!\n", __func__);
 		return -EINVAL;
@@ -1220,7 +1285,7 @@ static int mxc_isi_cap_s_parm(struct file *file, void *fh,
 	}
 
 	/* Get remote source pad subdev */
-	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	sd = mxc_isi_get_sensor_subdev(&mxc_isi->isi_cap.sd);
 	if (sd == NULL) {
 		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote subdev found!\n", __func__);
 		return -EINVAL;
@@ -1254,12 +1319,7 @@ static int mxc_isi_cap_enum_framesizes(struct file *file, void *priv,
 	}
 
 	/* Get remote source pad subdev */
-	sd = media_entity_to_v4l2_subdev(source_pad->entity);
-	if (sd == NULL) {
-		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote subdev found!\n", __func__);
-		return -EINVAL;
-	}
-
+	sd = mxc_isi_get_sensor_subdev(&mxc_isi->isi_cap.sd);
 	if (sd == NULL) {
 		v4l2_err(&mxc_isi->isi_cap.sd, "Can't find subdev\n");
 		return -ENODEV;
@@ -1321,10 +1381,10 @@ static int mxc_isi_cap_enum_frameintervals(struct file *file, void *fh,
 	}
 
 	/* Get remote source pad subdev */
-	sd = media_entity_to_v4l2_subdev(source_pad->entity);
+	sd = mxc_isi_get_sensor_subdev(&mxc_isi->isi_cap.sd);
 	if (sd == NULL) {
-		v4l2_err(mxc_isi->v4l2_dev, "%s, No remote subdev found!\n", __func__);
-		return -EINVAL;
+		v4l2_err(&mxc_isi->isi_cap.sd, "Can't find sensor subdev\n");
+		return -ENODEV;
 	}
 
 	ret = v4l2_subdev_call(sd, pad, enum_frame_interval, NULL, &fie);