Date:   Thu, 12 Jan 2017 12:17:31 +0100
From:   Pavel Machek <pavel@....cz>
To:     Sakari Ailus <sakari.ailus@....fi>
Cc:     ivo.g.dimitrov.75@...il.com, sre@...nel.org, pali.rohar@...il.com,
        linux-media@...r.kernel.org, galak@...eaurora.org,
        mchehab@....samsung.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: Add video bus switch

On Sat 2016-12-24 16:20:31, Pavel Machek wrote:
> 
> N900 contains front and back camera, with a switch between the
> two. This adds support for the switch component, and it is now
> possible to select between front and back cameras during runtime.
> 
> Signed-off-by: Sebastian Reichel <sre@...nel.org>
> Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
> Signed-off-by: Pavel Machek <pavel@....cz>

Can I get some feedback here? This works for me -- I can use both
cameras during one boot -- can I get it applied?

Thanks,
								Pavel

> diff --git a/Documentation/devicetree/bindings/media/video-bus-switch.txt b/Documentation/devicetree/bindings/media/video-bus-switch.txt
> new file mode 100644
> index 0000000..1b9f8e0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/video-bus-switch.txt
> @@ -0,0 +1,63 @@
> +Video Bus Switch Binding
> +========================
> +
> +This is a binding for a gpio controlled switch for camera interfaces. Such a
> +device is used on some embedded devices to connect two cameras to the same
> +interface of a image signal processor.
> +
> +Required properties
> +===================
> +
> +compatible	: must contain "video-bus-switch"
> +switch-gpios	: GPIO specifier for the gpio, which can toggle the
> +		  selected camera. The GPIO should be configured, so
> +		  that a disabled GPIO means, that the first port is
> +		  selected.
> +
> +Required Port nodes
> +===================
> +
> +More documentation on these bindings is available in
> +video-interfaces.txt in the same directory.
> +
> +reg		: The interface:
> +		  0 - port for image signal processor
> +		  1 - port for first camera sensor
> +		  2 - port for second camera sensor
> +
> +Example
> +=======
> +
> +video-bus-switch {
> +	compatible = "video-bus-switch"
> +	switch-gpios = <&gpio1 1 GPIO_ACTIVE_HIGH>;
> +
> +	ports {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		port@0 {
> +			reg = <0>;
> +
> +			csi_switch_in: endpoint {
> +				remote-endpoint = <&csi_isp>;
> +			};
> +		};
> +
> +		port@1 {
> +			reg = <1>;
> +
> +			csi_switch_out1: endpoint {
> +				remote-endpoint = <&csi_cam1>;
> +			};
> +		};
> +
> +		port@2 {
> +			reg = <2>;
> +
> +			csi_switch_out2: endpoint {
> +				remote-endpoint = <&csi_cam2>;
> +			};
> +		};
> +	};
> +};
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index ce4a96f..a4b509e 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -91,6 +91,16 @@ config VIDEO_OMAP3_DEBUG
>  	---help---
>  	  Enable debug messages on OMAP 3 camera controller driver.
>  
> +config VIDEO_BUS_SWITCH
> +	tristate "Video Bus switch"
> +	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> +	depends on MEDIA_CONTROLLER
> +	depends on OF
> +	---help---
> +	  Driver for a GPIO controlled video bus switch, which is used to
> +	  connect two camera sensors to the same port a the image signal
> +	  processor.
> +
>  config VIDEO_PXA27x
>  	tristate "PXA27x Quick Capture Interface driver"
>  	depends on VIDEO_DEV && HAS_DMA
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index 40b18d1..8eafc27 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -11,6 +11,8 @@ obj-$(CONFIG_VIDEO_MMP_CAMERA) += marvell-ccic/
>  obj-$(CONFIG_VIDEO_OMAP3)	+= omap3isp/
>  obj-$(CONFIG_VIDEO_PXA27x)	+= pxa_camera.o
>  
> +obj-$(CONFIG_VIDEO_BUS_SWITCH) += video-bus-switch.o
> +
>  obj-$(CONFIG_VIDEO_VIU) += fsl-viu.o
>  
>  obj-$(CONFIG_VIDEO_VIVID)		+= vivid/
> diff --git a/drivers/media/platform/video-bus-switch.c b/drivers/media/platform/video-bus-switch.c
> new file mode 100644
> index 0000000..6400cfc
> --- /dev/null
> +++ b/drivers/media/platform/video-bus-switch.c
> @@ -0,0 +1,387 @@
> +/*
> + * Generic driver for video bus switches
> + *
> + * Copyright (C) 2015 Sebastian Reichel <sre@...nel.org>
> + * Copyright (C) 2016 Pavel Machek <pavel@....cz>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + */
> +
> +#define DEBUG
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/gpio/consumer.h>
> +#include <media/v4l2-async.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-of.h>
> +
> +/*
> + * TODO:
> + * isp_subdev_notifier_complete() calls v4l2_device_register_subdev_nodes()
> + */
> +
> +#define CSI_SWITCH_SUBDEVS 2
> +#define CSI_SWITCH_PORTS 3
> +
> +enum vbs_state {
> +	CSI_SWITCH_DISABLED = 0,
> +	CSI_SWITCH_PORT_1 = 1,
> +	CSI_SWITCH_PORT_2 = 2,
> +};
> +
> +struct vbs_src_pads {
> +	struct media_entity *src;
> +	int src_pad;
> +};
> +
> +struct vbs_data {
> +	struct gpio_desc *swgpio;
> +	struct v4l2_subdev subdev;
> +	struct v4l2_async_notifier notifier;
> +	struct media_pad pads[CSI_SWITCH_PORTS];
> +	struct vbs_src_pads src_pads[CSI_SWITCH_PORTS];
> +	struct v4l2_of_endpoint vep[CSI_SWITCH_PORTS];
> +	enum vbs_state state;
> +};
> +
> +struct vbs_async_subdev {
> +	struct v4l2_subdev *sd;
> +	struct v4l2_async_subdev asd;
> +	u8 port;
> +};
> +
> +static int vbs_of_parse_nodes(struct device *dev, struct vbs_data *pdata)
> +{
> +	struct v4l2_async_notifier *notifier = &pdata->notifier;
> +	struct device_node *node = NULL;
> +
> +	notifier->subdevs = devm_kcalloc(dev, CSI_SWITCH_SUBDEVS,
> +		sizeof(*notifier->subdevs), GFP_KERNEL);
> +	if (!notifier->subdevs)
> +		return -ENOMEM;
> +
> +	notifier->num_subdevs = 0;
> +	while (notifier->num_subdevs < CSI_SWITCH_SUBDEVS &&
> +	       (node = of_graph_get_next_endpoint(dev->of_node, node))) {
> +		struct v4l2_of_endpoint vep;
> +		struct vbs_async_subdev *ssd;
> +
> +		/* skip first port (connected to isp) */
> +		v4l2_of_parse_endpoint(node, &vep);
> +		if (vep.base.port == 0) {
> +			struct device_node *ispnode;
> +
> +			ispnode = of_graph_get_remote_port_parent(node);
> +			if (!ispnode) {
> +				dev_warn(dev, "bad remote port parent\n");
> +				return -EINVAL;
> +			}
> +
> +			of_node_put(node);
> +			continue;
> +		}
> +
> +		ssd = devm_kzalloc(dev, sizeof(*ssd), GFP_KERNEL);
> +		if (!ssd) {
> +			of_node_put(node);
> +			return -ENOMEM;
> +		}
> +
> +		ssd->port = vep.base.port;
> +
> +		notifier->subdevs[notifier->num_subdevs] = &ssd->asd;
> +
> +		ssd->asd.match.of.node = of_graph_get_remote_port_parent(node);
> +		of_node_put(node);
> +		if (!ssd->asd.match.of.node) {
> +			dev_warn(dev, "bad remote port parent\n");
> +			return -EINVAL;
> +		}
> +
> +		ssd->asd.match_type = V4L2_ASYNC_MATCH_OF;
> +		pdata->vep[notifier->num_subdevs] = vep;
> +		notifier->num_subdevs++;
> +	}
> +
> +	return notifier->num_subdevs;
> +}
> +
> +static int vbs_registered(struct v4l2_subdev *sd)
> +{
> +	struct v4l2_device *v4l2_dev = sd->v4l2_dev;
> +	struct vbs_data *pdata;
> +	int err;
> +
> +	dev_dbg(sd->dev, "registered, init notifier...\n");
> +
> +	pdata = v4l2_get_subdevdata(sd);
> +
> +	err = v4l2_async_notifier_register(v4l2_dev, &pdata->notifier);
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static struct v4l2_subdev *vbs_get_remote_subdev(struct v4l2_subdev *sd)
> +{
> +	struct vbs_data *pdata = v4l2_get_subdevdata(sd);
> +	struct media_entity *src;
> +
> +	if (pdata->state == CSI_SWITCH_DISABLED)
> +		return ERR_PTR(-ENXIO);
> +
> +	src = pdata->src_pads[pdata->state].src;
> +
> +	return media_entity_to_v4l2_subdev(src);
> +}
> +
> +static int vbs_link_setup(struct media_entity *entity,
> +			  const struct media_pad *local,
> +			  const struct media_pad *remote, u32 flags)
> +{
> +	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
> +	struct vbs_data *pdata = v4l2_get_subdevdata(sd);
> +	bool enable = flags & MEDIA_LNK_FL_ENABLED;
> +
> +	if (local->index > CSI_SWITCH_PORTS - 1)
> +		return -ENXIO;
> +
> +	/* no configuration needed on source port */
> +	if (local->index == 0)
> +		return 0;
> +
> +	if (!enable) {
> +		if (local->index == pdata->state) {
> +			pdata->state = CSI_SWITCH_DISABLED;
> +
> +			/* Make sure we have both cameras enabled */
> +			gpiod_set_value(pdata->swgpio, 1);
> +			return 0;
> +		} else {
> +			return -EINVAL;
> +		}
> +	}
> +
> +	/* there can only be one active sink at the same time */
> +	if (pdata->state != CSI_SWITCH_DISABLED)
> +		return -EBUSY;
> +
> +	dev_dbg(sd->dev, "Link setup: going to config %d\n", local->index);
> +
> +	gpiod_set_value(pdata->swgpio, local->index == CSI_SWITCH_PORT_2);
> +	pdata->state = local->index;
> +
> +	sd = vbs_get_remote_subdev(sd);
> +	if (IS_ERR(sd))
> +		return PTR_ERR(sd);
> +
> +	pdata->subdev.ctrl_handler = sd->ctrl_handler;
> +
> +	return 0;
> +}
> +
> +static int vbs_subdev_notifier_bound(struct v4l2_async_notifier *async,
> +				     struct v4l2_subdev *subdev,
> +				     struct v4l2_async_subdev *asd)
> +{
> +	struct vbs_data *pdata = container_of(async,
> +		struct vbs_data, notifier);
> +	struct vbs_async_subdev *ssd =
> +		container_of(asd, struct vbs_async_subdev, asd);
> +	struct media_entity *sink = &pdata->subdev.entity;
> +	struct media_entity *src = &subdev->entity;
> +	int sink_pad = ssd->port;
> +	int src_pad;
> +
> +	if (sink_pad >= sink->num_pads) {
> +		dev_err(pdata->subdev.dev, "no sink pad in internal entity!\n");
> +		return -EINVAL;
> +	}
> +
> +	for (src_pad = 0; src_pad < subdev->entity.num_pads; src_pad++) {
> +		if (subdev->entity.pads[src_pad].flags & MEDIA_PAD_FL_SOURCE)
> +			break;
> +	}
> +
> +	if (src_pad >= src->num_pads) {
> +		dev_err(pdata->subdev.dev, "no source pad in external entity\n");
> +		return -EINVAL;
> +	}
> +
> +	pdata->src_pads[sink_pad].src = src;
> +	pdata->src_pads[sink_pad].src_pad = src_pad;
> +	ssd->sd = subdev;
> +
> +	return 0;
> +}
> +
> +static int vbs_subdev_notifier_complete(struct v4l2_async_notifier *async)
> +{
> +	struct vbs_data *pdata = container_of(async, struct vbs_data, notifier);
> +	struct media_entity *sink = &pdata->subdev.entity;
> +	int sink_pad;
> +
> +	for (sink_pad = 1; sink_pad < CSI_SWITCH_PORTS; sink_pad++) {
> +		struct media_entity *src = pdata->src_pads[sink_pad].src;
> +		int src_pad = pdata->src_pads[sink_pad].src_pad;
> +		int err;
> +
> +		err = media_create_pad_link(src, src_pad, sink, sink_pad, 0);
> +		if (err < 0)
> +			return err;
> +
> +		dev_dbg(pdata->subdev.dev, "create link: %s[%d] -> %s[%d])\n",
> +			src->name, src_pad, sink->name, sink_pad);
> +	}
> +
> +	return v4l2_device_register_subdev_nodes(pdata->subdev.v4l2_dev);
> +}
> +
> +static int vbs_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct v4l2_subdev *subdev = vbs_get_remote_subdev(sd);
> +
> +	if (IS_ERR(subdev))
> +		return PTR_ERR(subdev);
> +
> +	return v4l2_subdev_call(subdev, video, s_stream, enable);
> +}
> +
> +static int vbs_g_endpoint_config(struct v4l2_subdev *sd, struct v4l2_of_endpoint *cfg)
> +{
> +	struct vbs_data *pdata = v4l2_get_subdevdata(sd);
> +	dev_dbg(sd->dev, "vbs_g_endpoint_config... active port is %d\n", pdata->state);
> +	*cfg = pdata->vep[pdata->state - 1];
> +
> +	return 0;
> +}
> +
> +
> +static const struct v4l2_subdev_internal_ops vbs_internal_ops = {
> +	.registered = &vbs_registered,
> +};
> +
> +static const struct media_entity_operations vbs_media_ops = {
> +	.link_setup = vbs_link_setup,
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +/* subdev video operations */
> +static const struct v4l2_subdev_video_ops vbs_video_ops = {
> +	.s_stream = vbs_s_stream,
> +	.g_endpoint_config = vbs_g_endpoint_config,
> +};
> +
> +static const struct v4l2_subdev_ops vbs_ops = {
> +	.video = &vbs_video_ops,
> +};
> +
> +static int video_bus_switch_probe(struct platform_device *pdev)
> +{
> +	struct vbs_data *pdata;
> +	int err = 0;
> +
> +	/* platform data */
> +	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata) {
> +		dev_dbg(&pdev->dev, "video-bus-switch: not enough memory\n");
> +		return -ENOMEM;
> +	}
> +	platform_set_drvdata(pdev, pdata);
> +
> +	/* switch gpio */
> +	pdata->swgpio = devm_gpiod_get(&pdev->dev, "switch", GPIOD_OUT_HIGH);
> +	if (IS_ERR(pdata->swgpio)) {
> +		err = PTR_ERR(pdata->swgpio);
> +		dev_err(&pdev->dev, "Failed to request gpio: %d\n", err);
> +		return err;
> +	}
> +
> +	/* find sub-devices */
> +	err = vbs_of_parse_nodes(&pdev->dev, pdata);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "Failed to parse nodes: %d\n", err);
> +		return err;
> +	}
> +
> +	pdata->state = CSI_SWITCH_DISABLED;
> +	pdata->notifier.bound = vbs_subdev_notifier_bound;
> +	pdata->notifier.complete = vbs_subdev_notifier_complete;
> +
> +	/* setup subdev */
> +	pdata->pads[0].flags = MEDIA_PAD_FL_SOURCE;
> +	pdata->pads[1].flags = MEDIA_PAD_FL_SINK;
> +	pdata->pads[2].flags = MEDIA_PAD_FL_SINK;
> +
> +	v4l2_subdev_init(&pdata->subdev, &vbs_ops);
> +	pdata->subdev.dev = &pdev->dev;
> +	pdata->subdev.owner = pdev->dev.driver->owner;
> +	strncpy(pdata->subdev.name, dev_name(&pdev->dev), V4L2_SUBDEV_NAME_SIZE);
> +	v4l2_set_subdevdata(&pdata->subdev, pdata);
> +	pdata->subdev.entity.function = MEDIA_ENT_F_SWITCH;
> +	pdata->subdev.entity.flags |= MEDIA_ENT_F_SWITCH;
> +	pdata->subdev.entity.ops = &vbs_media_ops;
> +	pdata->subdev.internal_ops = &vbs_internal_ops;
> +	err = media_entity_pads_init(&pdata->subdev.entity, CSI_SWITCH_PORTS,
> +				pdata->pads);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "Failed to init media entity: %d\n", err);
> +		return err;
> +	}
> +
> +	/* register subdev */
> +	err = v4l2_async_register_subdev(&pdata->subdev);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "Failed to register v4l2 subdev: %d\n", err);
> +		media_entity_cleanup(&pdata->subdev.entity);
> +		return err;
> +	}
> +
> +	dev_info(&pdev->dev, "video-bus-switch registered\n");
> +
> +	return 0;
> +}
> +
> +static int video_bus_switch_remove(struct platform_device *pdev)
> +{
> +	struct vbs_data *pdata = platform_get_drvdata(pdev);
> +
> +	v4l2_async_notifier_unregister(&pdata->notifier);
> +	v4l2_async_unregister_subdev(&pdata->subdev);
> +	media_entity_cleanup(&pdata->subdev.entity);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id video_bus_switch_of_match[] = {
> +	{ .compatible = "video-bus-switch" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, video_bus_switch_of_match);
> +
> +static struct platform_driver video_bus_switch_driver = {
> +	.driver = {
> +		.name	= "video-bus-switch",
> +		.of_match_table = video_bus_switch_of_match,
> +	},
> +	.probe		= video_bus_switch_probe,
> +	.remove		= video_bus_switch_remove,
> +};
> +
> +module_platform_driver(video_bus_switch_driver);
> +
> +MODULE_AUTHOR("Sebastian Reichel <sre@...nel.org>");
> +MODULE_DESCRIPTION("Video Bus Switch");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:video-bus-switch");
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index cf778c5..448dbb5 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -25,6 +25,7 @@
>  #include <media/v4l2-dev.h>
>  #include <media/v4l2-fh.h>
>  #include <media/v4l2-mediabus.h>
> +#include <media/v4l2-of.h>
>  
>  /* generic v4l2_device notify callback notification values */
>  #define V4L2_SUBDEV_IR_RX_NOTIFY		_IOW('v', 0, u32)
> @@ -415,6 +416,8 @@ struct v4l2_subdev_video_ops {
>  			     const struct v4l2_mbus_config *cfg);
>  	int (*s_rx_buffer)(struct v4l2_subdev *sd, void *buf,
>  			   unsigned int *size);
> +	int (*g_endpoint_config)(struct v4l2_subdev *sd,
> +			    struct v4l2_of_endpoint *cfg);
>  };
>  
>  /**
> diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
> index 4890787..94648ab 100644
> --- a/include/uapi/linux/media.h
> +++ b/include/uapi/linux/media.h
> @@ -147,6 +147,7 @@ struct media_device_info {
>   * MEDIA_ENT_F_IF_VID_DECODER and/or MEDIA_ENT_F_IF_AUD_DECODER.
>   */
>  #define MEDIA_ENT_F_TUNER		(MEDIA_ENT_F_OLD_SUBDEV_BASE + 5)
> +#define MEDIA_ENT_F_SWITCH		(MEDIA_ENT_F_OLD_SUBDEV_BASE + 6)
>  
>  #define MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN	MEDIA_ENT_F_OLD_SUBDEV_BASE
>  
> 
> 



-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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