#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/log2.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/videodev2.h>
#include <linux/v4l2-mediabus.h>
#include <linux/module.h>

#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-of.h>
#include <media/v4l2-subdev.h>

struct ar0135 {
	struct v4l2_subdev subdev;
	struct media_pad pad;

	struct v4l2_mbus_framefmt format;
	struct v4l2_rect crop;

	struct {
		struct v4l2_ctrl *link_freq;
	};

	struct mutex power_lock;
	int power_count;

	struct regmap *regmap;
	struct gpio_desc *reset_gpio;

	struct clk *xclk;
	int xclk_freq;
};

static struct ar0135 *to_ar0135(struct v4l2_subdev *sd)
{
	return container_of(sd, struct ar0135, subdev);
}

static int ar0135_s_stream(struct v4l2_subdev *subdev, int enable)
{
	return 0;
}

/* -----------------------------------------------------------------------------
 * V4L2 subdev core operations
 */

static int ar0135_set_power(struct v4l2_subdev *subdev, int on)
{
	return 0;
}

/* -----------------------------------------------------------------------------
 * V4L2 subdev internal operations
 */

static int ar0135_registered(struct v4l2_subdev *subdev)
{
	pr_info("registered");
	return 0;
}

static struct v4l2_subdev_core_ops ar0135_subdev_core_ops = {
	.s_power	= ar0135_set_power,
};

static struct v4l2_subdev_video_ops ar0135_subdev_video_ops = {
	.s_stream	= ar0135_s_stream,
};

static struct v4l2_subdev_ops ar0135_subdev_ops = {
	.core	= &ar0135_subdev_core_ops,
	.video	= &ar0135_subdev_video_ops,
};

static const struct v4l2_subdev_internal_ops ar0135_subdev_internal_ops = {
	.registered = ar0135_registered,
};

/* -----------------------------------------------------------------------------
 * Driver initialization and probing
 */

static int ar0135_probe(struct i2c_client *client,
		const struct i2c_device_id *did)
{
	struct ar0135 *ar0135;
	int ret;

	pr_info("starting probe");

	ar0135 = devm_kzalloc(&client->dev, sizeof(*ar0135), GFP_KERNEL);
	if (!ar0135)
		return -ENOMEM;

	v4l2_i2c_subdev_init(&ar0135->subdev, client, &ar0135_subdev_ops);
	ar0135->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;

	ar0135->subdev.internal_ops = &ar0135_subdev_internal_ops;

	ar0135->pad.flags = MEDIA_PAD_FL_SOURCE;
        ar0135->subdev.entity.function = MEDIA_ENT_F_CAM_SENSOR;
	ret = media_entity_pads_init(&ar0135->subdev.entity, 1, &ar0135->pad);
	if (ret < 0)
		goto err;

	ar0135->subdev.dev = &client->dev;
	ret = v4l2_async_register_subdev(&ar0135->subdev);
	if (ret < 0)
		goto err;

	pr_info("finished probe");

	return 0;

err:
	media_entity_cleanup(&ar0135->subdev.entity);
	return ret;
}

static int ar0135_remove(struct i2c_client *client)
{
	struct v4l2_subdev *subdev = i2c_get_clientdata(client);

	v4l2_async_unregister_subdev(subdev);
	media_entity_cleanup(&subdev->entity);

	return 0;
}

static const struct i2c_device_id ar0135_id[] = {
	{ "ar0135", 0 },
	{}
};
MODULE_DEVICE_TABLE(i2c, ar0135_id);

#if IS_ENABLED(CONFIG_OF)
static const struct of_device_id ar0135_of_match[] = {
	{ .compatible = "onsemi,ar0135" },
	{}
};
MODULE_DEVICE_TABLE(of, ar0135_of_match);
#endif

static struct i2c_driver ar0135_driver = {
	.driver = {
		.name = "ar0135",
		.of_match_table = of_match_ptr(ar0135_of_match),
	},
	.probe		= ar0135_probe,
	.remove		= ar0135_remove,
	.id_table	= ar0135_id,
};

module_i2c_driver(ar0135_driver);

MODULE_DESCRIPTION("ON Semiconductor AR0135 Sensor");
MODULE_AUTHOR("Jack Mitchell <jack@embed.me.uk>");
MODULE_LICENSE("GPL");