On 12/31/20 8:29 AM, Paul Kocialkowski wrote:

[...]

+/* Base Driver */
+
+static int sun6i_mipi_csi2_suspend(struct device *dev)
+{
+	struct sun6i_mipi_csi2_dev *cdev = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(cdev->clk_mod);
+	clk_disable_unprepare(cdev->clk_bus);
+	reset_control_assert(cdev->reset);
+
+	return 0;
+}
+
+static int sun6i_mipi_csi2_resume(struct device *dev)
+{
+	struct sun6i_mipi_csi2_dev *cdev = dev_get_drvdata(dev);
+	int ret;
+
+	ret = reset_control_deassert(cdev->reset);
+	if (ret) {
+		dev_err(cdev->dev, "failed to deassert reset\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(cdev->clk_bus);
+	if (ret) {
+		dev_err(cdev->dev, "failed to enable bus clock\n");
+		goto error_reset;
+	}
+
+	ret = clk_prepare_enable(cdev->clk_mod);
+	if (ret) {
+		dev_err(cdev->dev, "failed to enable module clock\n");
+		goto error_clk_bus;
+	}
+
+	return 0;
+
+error_clk_bus:
+	clk_disable_unprepare(cdev->clk_bus);
+
+error_reset:
+	reset_control_assert(cdev->reset);
+
+	return ret;
+}
+
+static int sun6i_mipi_csi2_v4l2_setup(struct sun6i_mipi_csi2_dev *cdev)
+{
+	struct sun6i_mipi_csi2_video *video = &cdev->video;
+	struct v4l2_subdev *subdev = &video->subdev;
+	struct v4l2_async_notifier *notifier = &video->notifier;
+	struct fwnode_handle *handle;
+	struct v4l2_fwnode_endpoint *endpoint;
+	struct v4l2_async_subdev *subdev_async;
+	int ret;
+
+	/* Subdev */
+
+	v4l2_subdev_init(subdev, &sun6i_mipi_csi2_subdev_ops);
+	subdev->dev = cdev->dev;
+	subdev->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	strscpy(subdev->name, MODULE_NAME, sizeof(subdev->name));
+	v4l2_set_subdevdata(subdev, cdev);
+
+	/* Entity */
+
+	subdev->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+	subdev->entity.ops = &sun6i_mipi_csi2_entity_ops;
+
+	/* Pads */
+
+	video->pads[0].flags = MEDIA_PAD_FL_SINK;
+	video->pads[1].flags = MEDIA_PAD_FL_SOURCE;
+
+	ret = media_entity_pads_init(&subdev->entity, 2, video->pads);
+	if (ret)
+		return ret;
+
+	/* Endpoint */
+
+	handle = fwnode_graph_get_endpoint_by_id(dev_fwnode(cdev->dev), 0, 0,
+						 FWNODE_GRAPH_ENDPOINT_NEXT);
+	if (!handle) {
+		ret = -ENODEV;
+		goto error_media_entity;
+	}
+
+	endpoint = &video->endpoint;
+	endpoint->bus_type = V4L2_MBUS_CSI2_DPHY;
+
+	ret = v4l2_fwnode_endpoint_parse(handle, endpoint);
+	fwnode_handle_put(handle);
+	if (ret)
+		goto error_media_entity;
+
+	/* Notifier */
+
+	v4l2_async_notifier_init(notifier);
+
+	subdev_async = &video->subdev_async;
+	ret = v4l2_async_notifier_add_fwnode_remote_subdev(notifier, handle,
+							   subdev_async);
+	if (ret)
+		goto error_media_entity;
+
+	video->notifier.ops = &sun6i_mipi_csi2_notifier_ops;
+
+	ret = v4l2_async_subdev_notifier_register(subdev, notifier);
+	if (ret < 0)
+		goto error_notifier;
+
+	/* Subdev */
+
+	ret = v4l2_async_register_subdev(subdev);
+	if (ret < 0)
+		goto error_notifier_registered;
+
+	/* Runtime PM */
+
+	pm_runtime_enable(cdev->dev);

I would expect to see this before registering with the class, since
pm_runtime_get_sync() will fail if called before runtime PM is enabled.

+	pm_runtime_set_suspended(cdev->dev);

This is already the default.

+
+	return 0;
+
+error_notifier_registered:
+	v4l2_async_notifier_unregister(notifier);
+error_notifier:
+	v4l2_async_notifier_cleanup(notifier);
+error_media_entity:
+	media_entity_cleanup(&subdev->entity);
+
+	return ret;
+}
+
+static int sun6i_mipi_csi2_v4l2_teardown(struct sun6i_mipi_csi2_dev *cdev)
+{
+	struct sun6i_mipi_csi2_video *video = &cdev->video;
+	struct v4l2_subdev *subdev = &video->subdev;
+	struct v4l2_async_notifier *notifier = &video->notifier;
+
+	v4l2_async_unregister_subdev(subdev);
+	v4l2_async_notifier_unregister(notifier);
+	v4l2_async_notifier_cleanup(notifier);
+	media_entity_cleanup(&subdev->entity);
+	v4l2_device_unregister_subdev(subdev);
+

I would expect to see pm_runtime_suspend()/pm_runtime_disable() called
here, so you do not leak clock prepare/enable references.

Cheers,
Samuel

+	return 0;
+}
+
+static const struct regmap_config sun6i_mipi_csi2_regmap_config = {
+	.reg_bits       = 32,
+	.reg_stride     = 4,
+	.val_bits       = 32,
+	.max_register	= 0x400,
+};
+
+static int sun6i_mipi_csi2_probe(struct platform_device *pdev)
+{
+	struct sun6i_mipi_csi2_dev *cdev;
+	struct resource *res;
+	void __iomem *io_base;
+	int ret;
+
+	cdev = devm_kzalloc(&pdev->dev, sizeof(*cdev), GFP_KERNEL);
+	if (!cdev)
+		return -ENOMEM;
+
+	cdev->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	io_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(io_base))
+		return PTR_ERR(io_base);
+
+	cdev->regmap = devm_regmap_init_mmio(&pdev->dev, io_base,
+					     &sun6i_mipi_csi2_regmap_config);
+	if (IS_ERR(cdev->regmap)) {
+		dev_err(&pdev->dev, "failed to init register map\n");
+		return PTR_ERR(cdev->regmap);
+	}
+
+	cdev->clk_bus = devm_clk_get(&pdev->dev, "bus");
+	if (IS_ERR(cdev->clk_bus)) {
+		dev_err(&pdev->dev, "failed to acquire bus clock\n");
+		return PTR_ERR(cdev->clk_bus);
+	}
+
+	cdev->clk_mod = devm_clk_get(&pdev->dev, "mod");
+	if (IS_ERR(cdev->clk_mod)) {
+		dev_err(&pdev->dev, "failed to acquire mod clock\n");
+		return PTR_ERR(cdev->clk_mod);
+	}
+
+	cdev->reset = devm_reset_control_get_shared(&pdev->dev, NULL);
+	if (IS_ERR(cdev->reset)) {
+		dev_err(&pdev->dev, "failed to get reset controller\n");
+		return PTR_ERR(cdev->reset);
+	}
+
+	cdev->dphy = devm_phy_get(&pdev->dev, NULL);
+	if (IS_ERR(cdev->dphy)) {
+		dev_err(&pdev->dev, "failed to get the MIPI D-PHY\n");
+		return PTR_ERR(cdev->dphy);
+	}
+
+	ret = phy_init(cdev->dphy);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize the MIPI D-PHY\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, cdev);
+
+	ret = sun6i_mipi_csi2_v4l2_setup(cdev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int sun6i_mipi_csi2_remove(struct platform_device *pdev)
+{
+	struct sun6i_mipi_csi2_dev *cdev = platform_get_drvdata(pdev);
+
+	phy_exit(cdev->dphy);
+
+	return sun6i_mipi_csi2_v4l2_teardown(cdev);
+}
+
+static const struct dev_pm_ops sun6i_mipi_csi2_pm_ops = {
+	SET_RUNTIME_PM_OPS(sun6i_mipi_csi2_suspend, sun6i_mipi_csi2_resume,
+			   NULL)
+};
+
+static const struct of_device_id sun6i_mipi_csi2_of_match[] = {
+	{ .compatible = "allwinner,sun6i-a31-mipi-csi2" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sun6i_mipi_csi2_of_match);
+
+static struct platform_driver sun6i_mipi_csi2_platform_driver = {
+	.probe = sun6i_mipi_csi2_probe,
+	.remove = sun6i_mipi_csi2_remove,
+	.driver = {
+		.name = MODULE_NAME,
+		.of_match_table = of_match_ptr(sun6i_mipi_csi2_of_match),
+		.pm = &sun6i_mipi_csi2_pm_ops,
+	},
+};
+module_platform_driver(sun6i_mipi_csi2_platform_driver);
+
+MODULE_DESCRIPTION("Allwinner A31 MIPI CSI-2 Controller Driver");
+MODULE_AUTHOR("Paul Kocialkowski [off-list ref]");
+MODULE_LICENSE("GPL");

[...]

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