media: i2c: imx500: release rpk on subdev close

The pm_runtime reference is held for as long as imx500->fw_network is
populated.  This means the cached rpk (plus the pm reference that blocks
autosuspend) is present in the device state past userspace closing the
subdev fd, until the next VIDIOC_S_CTRL cleared or replaced it.

Add a .close internal op that calls imx500_clear_fw_network() when the
last userspace handle on the subdev is released.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>

Author: naushir

drivers/media/i2c/imx500.c

@@ -22,6 +22,7 @@
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-event.h>
+#include <media/v4l2-fh.h>
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-mediabus.h>
 
@@ -2331,6 +2332,26 @@ static const struct v4l2_ctrl_ops imx500_ctrl_ops = {
 	.s_ctrl = imx500_set_ctrl,
 };
 
+static int imx500_subdev_close(struct v4l2_subdev *sd,
+			       struct v4l2_subdev_fh *fh)
+{
+	struct imx500 *imx500 = to_imx500(sd);
+	/*
+	 * Release the cached rpk when the last userspace handle on the subdev
+	 * is closed. This also drops the pm_runtime reference ta taken in the
+	 * NETWORK_FW_FD branch of imx500_set_ctrl(), so the device can
+	 * autosuspend between sessions.
+	 */
+	if (v4l2_fh_is_singular(&fh->vfh))
+		imx500_clear_fw_network(imx500);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_internal_ops imx500_internal_ops = {
+	.close = imx500_subdev_close,
+};
+
 static const struct v4l2_ctrl_config imx500_notify_gains_ctrl = {
 	.ops = &imx500_ctrl_ops,
 	.id = V4L2_CID_NOTIFY_GAINS,
@@ -3632,6 +3653,7 @@ static int imx500_probe(struct i2c_client *client)
 		goto error_power_off;
 
 	/* Initialize subdev */
+	imx500->sd.internal_ops = &imx500_internal_ops;
 	imx500->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
 			    V4L2_SUBDEV_FL_HAS_EVENTS;
 	imx500->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;