media: marvell-ccic: use async notifier to get the sensor

An instance of a sensor on DT-based MMP2 platform is always going to be
created asynchronously.

Let's move the manual device creation away from the core to the Cafe
driver (used on OLPC XO-1, not present in DT) and set up appropriate
async matches: I2C on Cafe, FWNODE on MMP (OLPC XO-1.75).
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/marvell-ccic/cafe-driver.c

@@ -9,6 +9,7 @@
  *
  * Copyright 2006-11 One Laptop Per Child Association, Inc.
  * Copyright 2006-11 Jonathan Corbet <corbet@lwn.net>
+ * Copyright 2018 Lubomir Rintel <lkundrak@v3.sk>
  *
  * Written by Jonathan Corbet, corbet@lwn.net.
  *
@@ -25,6 +26,7 @@
 #include <linux/slab.h>
 #include <linux/videodev2.h>
 #include <media/v4l2-device.h>
+#include <media/i2c/ov7670.h>
 #include <linux/device.h>
 #include <linux/wait.h>
 #include <linux/delay.h>
@@ -50,6 +52,7 @@ struct cafe_camera {
 	int registered;			/* Fully initialized? */
 	struct mcam_camera mcam;
 	struct pci_dev *pdev;
+	struct i2c_adapter *i2c_adapter;
 	wait_queue_head_t smbus_wait;	/* Waiting on i2c events */
 };
 
@@ -349,15 +352,15 @@ static int cafe_smbus_setup(struct cafe_camera *cam)
 		return ret;
 	}
 
-	cam->mcam.i2c_adapter = adap;
+	cam->i2c_adapter = adap;
 	cafe_smbus_enable_irq(cam);
 	return 0;
 }
 
 static void cafe_smbus_shutdown(struct cafe_camera *cam)
 {
-	i2c_del_adapter(cam->mcam.i2c_adapter);
-	kfree(cam->mcam.i2c_adapter);
+	i2c_del_adapter(cam->i2c_adapter);
+	kfree(cam->i2c_adapter);
 }
 
 
@@ -450,6 +453,29 @@ static irqreturn_t cafe_irq(int irq, void *data)
 	return IRQ_RETVAL(handled);
 }
 
+/* -------------------------------------------------------------------------- */
+
+static struct ov7670_config sensor_cfg = {
+	/*
+	 * Exclude QCIF mode, because it only captures a tiny portion
+	 * of the sensor FOV
+	 */
+	.min_width = 320,
+	.min_height = 240,
+
+	/*
+	 * Set the clock speed for the XO 1; I don't believe this
+	 * driver has ever run anywhere else.
+	 */
+	.clock_speed = 45,
+	.use_smbus = 1,
+};
+
+struct i2c_board_info ov7670_info = {
+	.type = "ov7670",
+	.addr = 0x42 >> 1,
+	.platform_data = &sensor_cfg,
+};
 
 /* -------------------------------------------------------------------------- */
 /*
@@ -479,12 +505,6 @@ static int cafe_pci_probe(struct pci_dev *pdev,
 	mcam->plat_power_down = cafe_ctlr_power_down;
 	mcam->dev = &pdev->dev;
 	snprintf(mcam->bus_info, sizeof(mcam->bus_info), "PCI:%s", pci_name(pdev));
-	/*
-	 * Set the clock speed for the XO 1; I don't believe this
-	 * driver has ever run anywhere else.
-	 */
-	mcam->clock_speed = 45;
-	mcam->use_smbus = 1;
 	/*
 	 * Vmalloc mode for buffers is traditional with this driver.
 	 * We *might* be able to run DMA_contig, especially on a system
@@ -525,12 +545,21 @@ static int cafe_pci_probe(struct pci_dev *pdev,
 	if (ret)
 		goto out_pdown;
 
+	mcam->asd.match_type = V4L2_ASYNC_MATCH_I2C;
+	mcam->asd.match.i2c.adapter_id = i2c_adapter_id(cam->i2c_adapter);
+	mcam->asd.match.i2c.address = ov7670_info.addr;
+
 	ret = mccic_register(mcam);
-	if (ret == 0) {
+	if (ret)
+		goto out_smbus_shutdown;
+
+	if (i2c_new_device(cam->i2c_adapter, &ov7670_info)) {
 		cam->registered = 1;
 		return 0;
 	}
 
+	mccic_shutdown(mcam);
+out_smbus_shutdown:
 	cafe_smbus_shutdown(cam);
 out_pdown:
 	cafe_ctlr_power_down(mcam);

drivers/media/platform/marvell-ccic/mcam-core.c

@@ -4,6 +4,7 @@
  * so it needs platform-specific support outside of the core.
  *
  * Copyright 2011 Jonathan Corbet corbet@lwn.net
+ * Copyright 2018 Lubomir Rintel <lkundrak@v3.sk>
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -26,7 +27,6 @@
 #include <media/v4l2-ioctl.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-event.h>
-#include <media/i2c/ov7670.h>
 #include <media/videobuf2-vmalloc.h>
 #include <media/videobuf2-dma-contig.h>
 #include <media/videobuf2-dma-sg.h>
@@ -93,6 +93,9 @@ MODULE_PARM_DESC(buffer_mode,
 #define sensor_call(cam, o, f, args...) \
 	v4l2_subdev_call(cam->sensor, o, f, ##args)
 
+#define notifier_to_mcam(notifier) \
+	container_of(notifier, struct mcam_camera, notifier)
+
 static struct mcam_format_struct {
 	__u8 *desc;
 	__u32 pixelformat;
@@ -1715,23 +1718,94 @@ EXPORT_SYMBOL_GPL(mccic_irq);
 /*
  * Registration and such.
  */
-static struct ov7670_config sensor_cfg = {
+
+static int mccic_notify_bound(struct v4l2_async_notifier *notifier,
+	struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd)
+{
+	struct mcam_camera *cam = notifier_to_mcam(notifier);
+	int ret;
+
+	mutex_lock(&cam->s_mutex);
+	if (cam->sensor) {
+		cam_err(cam, "sensor already bound\n");
+		ret = -EBUSY;
+		goto out;
+	}
+
+	v4l2_set_subdev_hostdata(subdev, cam);
+	cam->sensor = subdev;
+
+	ret = mcam_cam_init(cam);
+	if (ret) {
+		cam->sensor = NULL;
+		goto out;
+	}
+
+	ret = mcam_setup_vb2(cam);
+	if (ret) {
+		cam->sensor = NULL;
+		goto out;
+	}
+
+	cam->vdev = mcam_v4l_template;
+	cam->vdev.v4l2_dev = &cam->v4l2_dev;
+	cam->vdev.lock = &cam->s_mutex;
+	cam->vdev.queue = &cam->vb_queue;
+	video_set_drvdata(&cam->vdev, cam);
+	ret = video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1);
+	if (ret) {
+		cam->sensor = NULL;
+		goto out;
+	}
+
+	cam_dbg(cam, "sensor %s bound\n", subdev->name);
+out:
+	mutex_unlock(&cam->s_mutex);
+	return ret;
+}
+
+static void mccic_notify_unbind(struct v4l2_async_notifier *notifier,
+	struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd)
+{
+	struct mcam_camera *cam = notifier_to_mcam(notifier);
+
+	mutex_lock(&cam->s_mutex);
+	if (cam->sensor != subdev) {
+		cam_err(cam, "sensor %s not bound\n", subdev->name);
+		goto out;
+	}
+
+	video_unregister_device(&cam->vdev);
+	cam->sensor = NULL;
+	cam_dbg(cam, "sensor %s unbound\n", subdev->name);
+
+out:
+	mutex_unlock(&cam->s_mutex);
+}
+
+static int mccic_notify_complete(struct v4l2_async_notifier *notifier)
+{
+	struct mcam_camera *cam = notifier_to_mcam(notifier);
+	int ret;
+
 	/*
-	 * Exclude QCIF mode, because it only captures a tiny portion
-	 * of the sensor FOV
+	 * Get the v4l2 setup done.
 	 */
-	.min_width = 320,
-	.min_height = 240,
-};
+	ret = v4l2_ctrl_handler_init(&cam->ctrl_handler, 10);
+	if (!ret)
+		cam->v4l2_dev.ctrl_handler = &cam->ctrl_handler;
+
+	return ret;
+}
 
+static const struct v4l2_async_notifier_operations mccic_notify_ops = {
+	.bound = mccic_notify_bound,
+	.unbind = mccic_notify_unbind,
+	.complete = mccic_notify_complete,
+};
 
 int mccic_register(struct mcam_camera *cam)
 {
-	struct i2c_board_info ov7670_info = {
-		.type = "ov7670",
-		.addr = 0x42 >> 1,
-		.platform_data = &sensor_cfg,
-	};
 	int ret;
 
 	/*
@@ -1744,17 +1818,20 @@ int mccic_register(struct mcam_camera *cam)
 		printk(KERN_ERR "marvell-cam: Cafe can't do S/G I/O, attempting vmalloc mode instead\n");
 		cam->buffer_mode = B_vmalloc;
 	}
+
 	if (!mcam_buffer_mode_supported(cam->buffer_mode)) {
 		printk(KERN_ERR "marvell-cam: buffer mode %d unsupported\n",
 				cam->buffer_mode);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
+
 	/*
 	 * Register with V4L
 	 */
 	ret = v4l2_device_register(cam->dev, &cam->v4l2_dev);
 	if (ret)
-		return ret;
+		goto out;
 
 	mutex_init(&cam->s_mutex);
 	cam->state = S_NOTREADY;
@@ -1764,43 +1841,20 @@ int mccic_register(struct mcam_camera *cam)
 	mcam_ctlr_init(cam);
 
 	/*
-	 * Get the v4l2 setup done.
+	 * Register sensor notifier.
 	 */
-	ret = v4l2_ctrl_handler_init(&cam->ctrl_handler, 10);
-	if (ret)
-		goto out_unregister;
-	cam->v4l2_dev.ctrl_handler = &cam->ctrl_handler;
-
-	/*
-	 * Try to find the sensor.
-	 */
-	sensor_cfg.clock_speed = cam->clock_speed;
-	sensor_cfg.use_smbus = cam->use_smbus;
-	cam->sensor = v4l2_i2c_new_subdev_board(&cam->v4l2_dev,
-			cam->i2c_adapter, &ov7670_info, NULL);
-	if (cam->sensor == NULL) {
-		ret = -ENODEV;
-		goto out_unregister;
+	v4l2_async_notifier_init(&cam->notifier);
+	ret = v4l2_async_notifier_add_subdev(&cam->notifier, &cam->asd);
+	if (ret) {
+		cam_warn(cam, "failed to add subdev to a notifier");
+		goto out;
 	}
 
-	ret = mcam_cam_init(cam);
-	if (ret)
-		goto out_unregister;
-
-	ret = mcam_setup_vb2(cam);
-	if (ret)
-		goto out_unregister;
-
-	mutex_lock(&cam->s_mutex);
-	cam->vdev = mcam_v4l_template;
-	cam->vdev.v4l2_dev = &cam->v4l2_dev;
-	cam->vdev.lock = &cam->s_mutex;
-	cam->vdev.queue = &cam->vb_queue;
-	video_set_drvdata(&cam->vdev, cam);
-	ret = video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1);
-	if (ret) {
-		mutex_unlock(&cam->s_mutex);
-		goto out_unregister;
+	cam->notifier.ops = &mccic_notify_ops;
+	ret = v4l2_async_notifier_register(&cam->v4l2_dev, &cam->notifier);
+	if (ret < 0) {
+		cam_warn(cam, "failed to register a sensor notifier");
+		goto out;
 	}
 
 	/*
@@ -1811,11 +1865,10 @@ int mccic_register(struct mcam_camera *cam)
 			cam_warn(cam, "Unable to alloc DMA buffers at load will try again later.");
 	}
 
-	mutex_unlock(&cam->s_mutex);
 	return 0;
 
-out_unregister:
-	v4l2_ctrl_handler_free(&cam->ctrl_handler);
+out:
+	v4l2_async_notifier_unregister(&cam->notifier);
 	v4l2_device_unregister(&cam->v4l2_dev);
 	return ret;
 }
@@ -1835,8 +1888,8 @@ void mccic_shutdown(struct mcam_camera *cam)
 	}
 	if (cam->buffer_mode == B_vmalloc)
 		mcam_free_dma_bufs(cam);
-	video_unregister_device(&cam->vdev);
 	v4l2_ctrl_handler_free(&cam->ctrl_handler);
+	v4l2_async_notifier_unregister(&cam->notifier);
 	v4l2_device_unregister(&cam->v4l2_dev);
 }
 EXPORT_SYMBOL_GPL(mccic_shutdown);

drivers/media/platform/marvell-ccic/mcam-core.h

@@ -102,14 +102,11 @@ struct mcam_camera {
 	 * These fields should be set by the platform code prior to
 	 * calling mcam_register().
 	 */
-	struct i2c_adapter *i2c_adapter;
 	unsigned char __iomem *regs;
 	unsigned regs_size; /* size in bytes of the register space */
 	spinlock_t dev_lock;
 	struct device *dev; /* For messages, dma alloc */
 	enum mcam_chip_id chip_id;
-	short int clock_speed;	/* Sensor clock speed, default 30 */
-	short int use_smbus;	/* SMBUS or straight I2c? */
 	enum mcam_buffer_mode buffer_mode;
 
 	int mclk_src;	/* which clock source the mclk derives from */
@@ -150,6 +147,8 @@ struct mcam_camera {
 	 * Subsystem structures.
 	 */
 	struct video_device vdev;
+	struct v4l2_async_notifier notifier;
+	struct v4l2_async_subdev asd;
 	struct v4l2_subdev *sensor;
 
 	/* Videobuf2 stuff */

drivers/media/platform/marvell-ccic/mmp-driver.c

@@ -4,12 +4,12 @@
  * to work with the Armada 610 as used in the OLPC 1.75 system.
  *
  * Copyright 2011 Jonathan Corbet <corbet@lwn.net>
+ * Copyright 2018 Lubomir Rintel <lkundrak@v3.sk>
  */
 
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
@@ -314,6 +314,7 @@ static int mmpcam_probe(struct platform_device *pdev)
 	struct mmp_camera *cam;
 	struct mcam_camera *mcam;
 	struct resource *res;
+	struct fwnode_handle *ep;
 	struct mmp_camera_platform_data *pdata;
 	int ret;
 
@@ -328,7 +329,6 @@ static int mmpcam_probe(struct platform_device *pdev)
 	mcam->plat_power_down = mmpcam_power_down;
 	mcam->calc_dphy = mmpcam_calc_dphy;
 	mcam->dev = &pdev->dev;
-	mcam->use_smbus = 0;
 	pdata = pdev->dev.platform_data;
 	if (pdata) {
 		mcam->mclk_src = pdata->mclk_src;
@@ -372,15 +372,6 @@ static int mmpcam_probe(struct platform_device *pdev)
 	cam->power_regs = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(cam->power_regs))
 		return PTR_ERR(cam->power_regs);
-	/*
-	 * Find the i2c adapter.  This assumes, of course, that the
-	 * i2c bus is already up and functioning.
-	 */
-	mcam->i2c_adapter = platform_get_drvdata(pdata->i2c_device);
-	if (mcam->i2c_adapter == NULL) {
-		dev_err(&pdev->dev, "No i2c adapter\n");
-		return -ENODEV;
-	}
 	/*
 	 * Sensor GPIO pins.
 	 */
@@ -403,6 +394,19 @@ static int mmpcam_probe(struct platform_device *pdev)
 
 	mcam_init_clk(mcam);
 
+	/*
+	 * Create a match of the sensor against its OF node.
+	 */
+	ep = fwnode_graph_get_next_endpoint(of_fwnode_handle(pdev->dev.of_node),
+					    NULL);
+	if (!ep)
+		return -ENODEV;
+
+	mcam->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
+	mcam->asd.match.fwnode = fwnode_graph_get_remote_port_parent(ep);
+
+	fwnode_handle_put(ep);
+
 	/*
 	 * Power the device up and hand it off to the core.
 	 */
@@ -412,6 +416,7 @@ static int mmpcam_probe(struct platform_device *pdev)
 	ret = mccic_register(mcam);
 	if (ret)
 		goto out_power_down;
+
 	/*
 	 * Finally, set up our IRQ now that the core is ready to
 	 * deal with it.

include/linux/platform_data/media/mmp-camera.h

@@ -12,7 +12,6 @@ enum dphy3_algo {
 };
 
 struct mmp_camera_platform_data {
-	struct platform_device *i2c_device;
 	int sensor_power_gpio;
 	int sensor_reset_gpio;
 	enum v4l2_mbus_type bus_type;