diff mbox

[RFC/PATCH] media: Add video bus switch

Message ID 20161222133938.GA30259@amd (mailing list archive)
State New, archived
Headers show

Commit Message

Pavel Machek Dec. 22, 2016, 1:39 p.m. UTC
N900 contains front and back camera, with a switch between the
two. This adds support for the swich component.

Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

--

I see this needs dts documentation, anything else than needs to be
done?

Thanks,
									Pavel

Comments

Sebastian Reichel Dec. 22, 2016, 2:32 p.m. UTC | #1
Hi Pavel,

On Thu, Dec 22, 2016 at 02:39:38PM +0100, Pavel Machek wrote:
> N900 contains front and back camera, with a switch between the
> two. This adds support for the swich component.
> 
> Signed-off-by: Sebastian Reichel <sre@kernel.org>
> Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
> Signed-off-by: Pavel Machek <pavel@ucw.cz>
> 
> --
> 
> I see this needs dts documentation, anything else than needs to be
> done?

Yes. This driver takes care of the switch gpio, but the cameras also
use different bus settings. Currently omap3isp gets the bus-settings
from the link connected to the CCP2 port in DT at probe time (*).

So there are two general problems:

1. Settings must be applied before the streaming starts instead of
at probe time, since the settings may change (based one the selected
camera). That should be fairly easy to implement by just moving the
code to the s_stream callback as far as I can see.

2. omap3isp should try to get the bus settings from using a callback
in the connected driver instead of loading it from DT. Then the
video-bus-switch can load the bus-settings from its downstream links
in DT and propagate the correct ones to omap3isp based on the
selected port. The DT loading part should actually remain in omap3isp
as fallback, in case it does not find a callback in the connected driver.
That way everything is backward compatible and the DT variant is
nice for 1-on-1 scenarios.

Apart from that Sakari told me at ELCE, that the port numbers
should be reversed to match the order of other drivers. That's
obviously very easy to do :)

Regarding the binding document. I actually did write one:
https://git.kernel.org/cgit/linux/kernel/git/sre/linux-n900.git/commit/?h=n900-camera&id=81e74af53fe6d180616b05792f78badc615e871f

So all in all it shouldn't be that hard to implement the remaining
bits.

(*) Actually it does not for CCP2, but there are some old patches
from Sakari adding it for CCP2. It is implemented for parallel port
and CSI in this way.

-- Sebastian
Pavel Machek Dec. 22, 2016, 8:53 p.m. UTC | #2
Hi!

> > I see this needs dts documentation, anything else than needs to be
> > done?
> 
> Yes. This driver takes care of the switch gpio, but the cameras also
> use different bus settings. Currently omap3isp gets the bus-settings
> from the link connected to the CCP2 port in DT at probe time (*).
> 
> So there are two general problems:
> 
> 1. Settings must be applied before the streaming starts instead of
> at probe time, since the settings may change (based one the selected
> camera). That should be fairly easy to implement by just moving the
> code to the s_stream callback as far as I can see.

Ok, I see, where "the code" is basically in vbs_link_setup, right?

> 2. omap3isp should try to get the bus settings from using a callback
> in the connected driver instead of loading it from DT. Then the
> video-bus-switch can load the bus-settings from its downstream links
> in DT and propagate the correct ones to omap3isp based on the
> selected port. The DT loading part should actually remain in omap3isp
> as fallback, in case it does not find a callback in the connected driver.
> That way everything is backward compatible and the DT variant is
> nice for 1-on-1 scenarios.

So basically... (struct isp_bus_cfg *) isd->bus would change in
isp_pipeline_enable()...? 

> Apart from that Sakari told me at ELCE, that the port numbers
> should be reversed to match the order of other drivers. That's
> obviously very easy to do :)

Ok, I guess that can come later :-).

> Regarding the binding document. I actually did write one:
> https://git.kernel.org/cgit/linux/kernel/git/sre/linux-n900.git/commit/?h=n900-camera&id=81e74af53fe6d180616b05792f78badc615e871f

Thanks, got it.

> So all in all it shouldn't be that hard to implement the remaining
> bits.

:-).

> (*) Actually it does not for CCP2, but there are some old patches
> from Sakari adding it for CCP2. It is implemented for parallel port
> and CSI in this way.

I think I got the patches in my tree. Camera currently works for me.

Thanks,
									Pavel
Sebastian Reichel Dec. 22, 2016, 11:11 p.m. UTC | #3
Hi,

On Thu, Dec 22, 2016 at 09:53:17PM +0100, Pavel Machek wrote:
> > 1. Settings must be applied before the streaming starts instead of
> > at probe time, since the settings may change (based one the selected
> > camera). That should be fairly easy to implement by just moving the
> > code to the s_stream callback as far as I can see.
> 
> Ok, I see, where "the code" is basically in vbs_link_setup, right?

I'm not talking about the video bus switch, but about omap3isp.
omap3isp must update the buscfg registers when it starts streaming
instead of at probe time. I just checked and it actually seems to do
so already. So the problem is only updating the buscfg inside of
ccp2_s_stream() before writing the device registers. See next
paragraph for more details.

> > 2. omap3isp should try to get the bus settings from using a callback
> > in the connected driver instead of loading it from DT. Then the
> > video-bus-switch can load the bus-settings from its downstream links
> > in DT and propagate the correct ones to omap3isp based on the
> > selected port. The DT loading part should actually remain in omap3isp
> > as fallback, in case it does not find a callback in the connected driver.
> > That way everything is backward compatible and the DT variant is
> > nice for 1-on-1 scenarios.
> 
> So basically... (struct isp_bus_cfg *) isd->bus would change in
> isp_pipeline_enable()...? 

isp_of_parse_node_csi1(), which is called by isp_of_parse_node()
inits buscfg using DT information. This does not work for N900,
which needs two different buscfg settings based on the selected
camera. I suggest to add a callback to the subdevice instead.

So something like pseudocode is needed in ccp2_s_stream():

/* get current buscfg */
if (subdevice->get_buscfg)
    buscfg = subdevice->get_buscfg();
else
    buscfg = isp_of_parse_node_csi1();

/* configure device registers */
ccp2_if_configure(buscfg);

This new callback must be implemented in the video-bus-switch,
so that it returns the buscfg based upon the selected camera.

> > Apart from that Sakari told me at ELCE, that the port numbers
> > should be reversed to match the order of other drivers. That's
> > obviously very easy to do :)
> 
> Ok, I guess that can come later :-).
> 
> > Regarding the binding document. I actually did write one:
> > https://git.kernel.org/cgit/linux/kernel/git/sre/linux-n900.git/commit/?h=n900-camera&id=81e74af53fe6d180616b05792f78badc615e871f
> 
> Thanks, got it.
> 
> > So all in all it shouldn't be that hard to implement the remaining
> > bits.
> 
> :-).
> 
> > (*) Actually it does not for CCP2, but there are some old patches
> > from Sakari adding it for CCP2. It is implemented for parallel port
> > and CSI in this way.
> 
> I think I got the patches in my tree. Camera currently works for me.

If you have working camera you have the CCP2 DT patches in your tree.
They are not yet mainline, though. As far as I can see.

-- Sebastian
diff mbox

Patch

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index d944421..0a99e63 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 && VIDEO_V4L2 && HAS_DMA
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index 5b3cb27..a4c9eab 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..1a5d944
--- /dev/null
+++ b/drivers/media/platform/video-bus-switch.c
@@ -0,0 +1,371 @@ 
+/*
+ * Generic driver for video bus switches
+ *
+ * Copyright (C) 2015 Sebastian Reichel <sre@kernel.org>
+ *
+ * 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,
+	CSI_SWITCH_PORT_1,
+	CSI_SWITCH_PORT_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];
+	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;
+		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;
+
+	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 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,
+};
+
+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) {
+		printk("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@kernel.org>");
+MODULE_DESCRIPTION("Video Bus Switch");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:video-bus-switch");