Re: [PATCH v4 09/15] media: sunxi: Add support for the A31 MIPI CSI-2 controller

[Paul Kocialkowski <paul.kocialkowski@bootlin.com>]

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Hi Samuel,

On Sat 09 Jan 21, 16:24, Samuel Holland wrote:
> On 12/31/20 8:29 AM, Paul Kocialkowski wrote:
> > The A31 MIPI CSI-2 controller is a dedicated MIPI CSI-2 bridge
> > found on Allwinner SoCs such as the A31 and V3/V3s.
> > 
> > It is a standalone block, connected to the CSI controller on one side
> > and to the MIPI D-PHY block on the other. It has a dedicated address
> > space, interrupt line and clock.
> > 
> > It is represented as a V4L2 subdev to the CSI controller and takes a
> > MIPI CSI-2 sensor as its own subdev, all using the fwnode graph and
> > media controller API.
> > 
> > Only 8-bit and 10-bit Bayer formats are currently supported.
> > While up to 4 internal channels to the CSI controller exist, only one
> > is currently supported by this implementation.
> > 
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > ---
> >  drivers/media/platform/sunxi/Kconfig          |   1 +
> >  drivers/media/platform/sunxi/Makefile         |   1 +
> >  .../platform/sunxi/sun6i-mipi-csi2/Kconfig    |  12 +
> >  .../platform/sunxi/sun6i-mipi-csi2/Makefile   |   4 +
> >  .../sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c   | 590 ++++++++++++++++++
> >  .../sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h   | 117 ++++
> >  6 files changed, 725 insertions(+)
> >  create mode 100644 drivers/media/platform/sunxi/sun6i-mipi-csi2/Kconfig
> >  create mode 100644 drivers/media/platform/sunxi/sun6i-mipi-csi2/Makefile
> >  create mode 100644 drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> >  create mode 100644 drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h
> > 
> > diff --git a/drivers/media/platform/sunxi/Kconfig b/drivers/media/platform/sunxi/Kconfig
> > index 7151cc249afa..9684e07454ad 100644
> > --- a/drivers/media/platform/sunxi/Kconfig
> > +++ b/drivers/media/platform/sunxi/Kconfig
> > @@ -2,3 +2,4 @@
> >  
> >  source "drivers/media/platform/sunxi/sun4i-csi/Kconfig"
> >  source "drivers/media/platform/sunxi/sun6i-csi/Kconfig"
> > +source "drivers/media/platform/sunxi/sun6i-mipi-csi2/Kconfig"
> > diff --git a/drivers/media/platform/sunxi/Makefile b/drivers/media/platform/sunxi/Makefile
> > index fc537c9f5ca9..887a7cae8fca 100644
> > --- a/drivers/media/platform/sunxi/Makefile
> > +++ b/drivers/media/platform/sunxi/Makefile
> > @@ -2,5 +2,6 @@
> >  
> >  obj-y		+= sun4i-csi/
> >  obj-y		+= sun6i-csi/
> > +obj-y		+= sun6i-mipi-csi2/
> >  obj-y		+= sun8i-di/
> >  obj-y		+= sun8i-rotate/
> > diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/Kconfig b/drivers/media/platform/sunxi/sun6i-mipi-csi2/Kconfig
> > new file mode 100644
> > index 000000000000..47f1bb0779a8
> > --- /dev/null
> > +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/Kconfig
> > @@ -0,0 +1,12 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +config VIDEO_SUN6I_MIPI_CSI2
> > +	tristate "Allwinner A31 MIPI CSI-2 Controller Driver"
> > +	depends on ARCH_SUNXI || COMPILE_TEST
> > +	depends on PM && COMMON_CLK && VIDEO_V4L2
> > +	select REGMAP_MMIO
> > +	select PHY_SUN6I_MIPI_DPHY
> > +	select MEDIA_CONTROLLER
> > +	select VIDEO_V4L2_SUBDEV_API
> > +	select V4L2_FWNODE
> > +	help
> > +	   Support for the Allwinner A31 MIPI CSI-2 Controller.
> > diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/Makefile b/drivers/media/platform/sunxi/sun6i-mipi-csi2/Makefile
> > new file mode 100644
> > index 000000000000..14e4e03818b5
> > --- /dev/null
> > +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/Makefile
> > @@ -0,0 +1,4 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +sun6i-mipi-csi2-y += sun6i_mipi_csi2.o
> > +
> > +obj-$(CONFIG_VIDEO_SUN6I_MIPI_CSI2) += sun6i-mipi-csi2.o
> > diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> > new file mode 100644
> > index 000000000000..87307beda4cf
> > --- /dev/null
> > +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> > @@ -0,0 +1,590 @@
> [...]
> > +/* 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.

You're right, and I actually made the same mistake on another driver too.
Will fix!

> > +	pm_runtime_set_suspended(cdev->dev);
> 
> This is already the default.

Yeah, I just wanted to make this explicit for someone reading the driver
who's not so familiar with rpm internals. I guess it doesn't hurt.

> > +
> > +	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.

Sure, I also forgot that.

Thanks a lot for the review!

Cheers,

Paul

> 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 <paul.kocialkowski@bootlin.com>");
> > +MODULE_LICENSE("GPL");
> [...]

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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