/*
 * Driver for Analog Devices ADV748X CSI-2 Transmitter
 *
 * Copyright (C) 2017 Renesas Electronics Corp.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */

#include <linux/module.h>
#include <linux/mutex.h>

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

#include "adv748x.h"

static bool is_txa(struct adv748x_csi2 *tx)
{
	return tx == &tx->state->txa;
}

static int adv748x_csi2_set_virtual_channel(struct adv748x_csi2 *tx,
					    unsigned int vc)
{
	return tx_write(tx, ADV748X_CSI_VC_REF, vc << ADV748X_CSI_VC_REF_SHIFT);
}

/**
 * adv748x_csi2_register_link : Register and link internal entities
 *
 * @tx: CSI2 private entity
 * @v4l2_dev: Video registration device
 * @src: Source subdevice to establish link
 * @src_pad: Pad number of source to link to this @tx
 *
 * Ensure that the subdevice is registered against the v4l2_device, and link the
 * source pad to the sink pad of the CSI2 bus entity.
 */
static int adv748x_csi2_register_link(struct adv748x_csi2 *tx,
				      struct v4l2_device *v4l2_dev,
				      struct v4l2_subdev *src,
				      unsigned int src_pad)
{
	int enabled = MEDIA_LNK_FL_ENABLED;
	int ret;

	/*
	 * Dynamic linking of the AFE is not supported.
	 * Register the links as immutable.
	 */
	enabled |= MEDIA_LNK_FL_IMMUTABLE;

	if (!src->v4l2_dev) {
		ret = v4l2_device_register_subdev(v4l2_dev, src);
		if (ret)
			return ret;
	}

	return media_create_pad_link(&src->entity, src_pad,
				     &tx->sd.entity, ADV748X_CSI2_SINK,
				     enabled);
}

/* -----------------------------------------------------------------------------
 * v4l2_subdev_internal_ops
 *
 * We use the internal registered operation to be able to ensure that our
 * incremental subdevices (not connected in the forward path) can be registered
 * against the resulting video path and media device.
 */

static int adv748x_csi2_registered(struct v4l2_subdev *sd)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
	struct adv748x_state *state = tx->state;

	adv_dbg(state, "Registered %s (%s)", is_txa(tx) ? "TXA":"TXB",
			sd->name);

	/*
	 * The adv748x hardware allows the AFE to route through the TXA, however
	 * this is not currently supported in this driver.
	 *
	 * Link HDMI->TXA, and AFE->TXB directly.
	 */
	if (is_txa(tx)) {
		return adv748x_csi2_register_link(tx, sd->v4l2_dev,
						  &state->hdmi.sd,
						  ADV748X_HDMI_SOURCE);
	} else {
		return adv748x_csi2_register_link(tx, sd->v4l2_dev,
						  &state->afe.sd,
						  ADV748X_AFE_SOURCE);
	}
}

static const struct v4l2_subdev_internal_ops adv748x_csi2_internal_ops = {
	.registered = adv748x_csi2_registered,
};

/* -----------------------------------------------------------------------------
 * v4l2_subdev_video_ops
 */

static int adv748x_csi2_s_stream(struct v4l2_subdev *sd, int enable)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
	struct v4l2_subdev *src;

	src = adv748x_get_remote_sd(&tx->pads[ADV748X_CSI2_SINK]);
	if (!src)
		return -EPIPE;

	return v4l2_subdev_call(src, video, s_stream, enable);
}

static const struct v4l2_subdev_video_ops adv748x_csi2_video_ops = {
	.s_stream = adv748x_csi2_s_stream,
};

/* -----------------------------------------------------------------------------
 * v4l2_subdev_pad_ops
 *
 * The CSI2 bus pads are ignorant to the data sizes or formats.
 * But we must support setting the pad formats for format propagation.
 */

static struct v4l2_mbus_framefmt *
adv748x_csi2_get_pad_format(struct v4l2_subdev *sd,
			    struct v4l2_subdev_pad_config *cfg,
			    unsigned int pad, u32 which)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);

	if (which == V4L2_SUBDEV_FORMAT_TRY)
		return v4l2_subdev_get_try_format(sd, cfg, pad);

	return &tx->format;
}

static int adv748x_csi2_get_format(struct v4l2_subdev *sd,
				   struct v4l2_subdev_pad_config *cfg,
				   struct v4l2_subdev_format *sdformat)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
	struct adv748x_state *state = tx->state;
	struct v4l2_mbus_framefmt *mbusformat;

	mbusformat = adv748x_csi2_get_pad_format(sd, cfg, sdformat->pad,
						 sdformat->which);
	if (!mbusformat)
		return -EINVAL;

	mutex_lock(&state->mutex);

	sdformat->format = *mbusformat;

	mutex_unlock(&state->mutex);

	return 0;
}

static int adv748x_csi2_set_format(struct v4l2_subdev *sd,
				   struct v4l2_subdev_pad_config *cfg,
				   struct v4l2_subdev_format *sdformat)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
	struct adv748x_state *state = tx->state;
	struct v4l2_mbus_framefmt *mbusformat;
	int ret = 0;

	mbusformat = adv748x_csi2_get_pad_format(sd, cfg, sdformat->pad,
						 sdformat->which);
	if (!mbusformat)
		return -EINVAL;

	mutex_lock(&state->mutex);

	if (sdformat->pad == ADV748X_CSI2_SOURCE) {
		const struct v4l2_mbus_framefmt *sink_fmt;

		sink_fmt = adv748x_csi2_get_pad_format(sd, cfg,
						       ADV748X_CSI2_SINK,
						       sdformat->which);

		if (!sink_fmt) {
			ret = -EINVAL;
			goto unlock;
		}

		sdformat->format = *sink_fmt;
	}

	*mbusformat = sdformat->format;

unlock:
	mutex_unlock(&state->mutex);

	return ret;
}

static const struct v4l2_subdev_pad_ops adv748x_csi2_pad_ops = {
	.get_fmt = adv748x_csi2_get_format,
	.set_fmt = adv748x_csi2_set_format,
};

/* -----------------------------------------------------------------------------
 * v4l2_subdev_ops
 */

static const struct v4l2_subdev_ops adv748x_csi2_ops = {
	.video = &adv748x_csi2_video_ops,
	.pad = &adv748x_csi2_pad_ops,
};

/* -----------------------------------------------------------------------------
 * Subdev module and controls
 */

int adv748x_csi2_set_pixelrate(struct v4l2_subdev *sd, s64 rate)
{
	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);

	if (!tx->pixel_rate)
		return -EINVAL;

	return v4l2_ctrl_s_ctrl_int64(tx->pixel_rate, rate);
}

static int adv748x_csi2_s_ctrl(struct v4l2_ctrl *ctrl)
{
	switch (ctrl->id) {
	case V4L2_CID_PIXEL_RATE:
		return 0;
	default:
		return -EINVAL;
	}
}

static const struct v4l2_ctrl_ops adv748x_csi2_ctrl_ops = {
	.s_ctrl = adv748x_csi2_s_ctrl,
};

static int adv748x_csi2_init_controls(struct adv748x_csi2 *tx)
{

	v4l2_ctrl_handler_init(&tx->ctrl_hdl, 1);

	tx->pixel_rate = v4l2_ctrl_new_std(&tx->ctrl_hdl,
					   &adv748x_csi2_ctrl_ops,
					   V4L2_CID_PIXEL_RATE, 1, INT_MAX,
					   1, 1);

	tx->sd.ctrl_handler = &tx->ctrl_hdl;
	if (tx->ctrl_hdl.error) {
		v4l2_ctrl_handler_free(&tx->ctrl_hdl);
		return tx->ctrl_hdl.error;
	}

	return v4l2_ctrl_handler_setup(&tx->ctrl_hdl);
}

int adv748x_csi2_init(struct adv748x_state *state, struct adv748x_csi2 *tx)
{
	struct device_node *ep;
	int ret;

	/* We can not use container_of to get back to the state with two TXs */
	tx->state = state;
	tx->page = is_txa(tx) ? ADV748X_PAGE_TXA : ADV748X_PAGE_TXB;

	ep = state->endpoints[is_txa(tx) ? ADV748X_PORT_TXA : ADV748X_PORT_TXB];
	if (!ep) {
		adv_err(state, "No endpoint found for %s\n",
				is_txa(tx) ? "txa" : "txb");
		return -ENODEV;
	}

	/* Initialise the virtual channel */
	adv748x_csi2_set_virtual_channel(tx, 0);

	adv748x_subdev_init(&tx->sd, state, &adv748x_csi2_ops,
			    MEDIA_ENT_F_VID_IF_BRIDGE,
			    is_txa(tx) ? "txa" : "txb");

	/* Ensure that matching is based upon the endpoint fwnodes */
	tx->sd.fwnode = of_fwnode_handle(ep);

	/* Register internal ops for incremental subdev registration */
	tx->sd.internal_ops = &adv748x_csi2_internal_ops;

	tx->pads[ADV748X_CSI2_SINK].flags = MEDIA_PAD_FL_SINK;
	tx->pads[ADV748X_CSI2_SOURCE].flags = MEDIA_PAD_FL_SOURCE;

	ret = media_entity_pads_init(&tx->sd.entity, ADV748X_CSI2_NR_PADS,
				     tx->pads);
	if (ret)
		return ret;

	ret = adv748x_csi2_init_controls(tx);
	if (ret)
		goto err_free_media;

	ret = v4l2_async_register_subdev(&tx->sd);
	if (ret)
		goto err_free_ctrl;

	return 0;

err_free_ctrl:
	v4l2_ctrl_handler_free(&tx->ctrl_hdl);
err_free_media:
	media_entity_cleanup(&tx->sd.entity);

	return ret;
}

void adv748x_csi2_cleanup(struct adv748x_csi2 *tx)
{
	v4l2_async_unregister_subdev(&tx->sd);
	media_entity_cleanup(&tx->sd.entity);
	v4l2_ctrl_handler_free(&tx->ctrl_hdl);
}