root/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_bridge.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2021-2022 Bootlin
 * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
 */

#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>

#include "sun6i_csi.h"
#include "sun6i_csi_bridge.h"
#include "sun6i_csi_reg.h"

/* Helpers */

void sun6i_csi_bridge_dimensions(struct sun6i_csi_device *csi_dev,
                                 unsigned int *width, unsigned int *height)
{
        if (width)
                *width = csi_dev->bridge.mbus_format.width;
        if (height)
                *height = csi_dev->bridge.mbus_format.height;
}

void sun6i_csi_bridge_format(struct sun6i_csi_device *csi_dev,
                             u32 *mbus_code, u32 *field)
{
        if (mbus_code)
                *mbus_code = csi_dev->bridge.mbus_format.code;
        if (field)
                *field = csi_dev->bridge.mbus_format.field;
}

/* Format */

static const struct sun6i_csi_bridge_format sun6i_csi_bridge_formats[] = {
        /* Bayer */
        {
                .mbus_code              = MEDIA_BUS_FMT_SBGGR8_1X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGBRG8_1X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGRBG8_1X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SRGGB8_1X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SBGGR10_1X10,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGBRG10_1X10,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGRBG10_1X10,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SRGGB10_1X10,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SBGGR12_1X12,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGBRG12_1X12,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SGRBG12_1X12,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_SRGGB12_1X12,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        /* RGB */
        {
                .mbus_code              = MEDIA_BUS_FMT_RGB565_2X8_LE,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_RGB565_2X8_BE,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
        /* YUV422 */
        {
                .mbus_code              = MEDIA_BUS_FMT_YUYV8_2X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_YUYV,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_YVYU,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_UYVY8_2X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_YVYU8_2X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_YVYU,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_YUYV,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_UYVY8_2X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_VYUY8_2X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_YUYV8_1X16,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_YUYV,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_YVYU,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_UYVY8_1X16,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_YVYU8_1X16,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_YVYU,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_YUYV,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_UYVY8_1X16,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
        },
        {
                .mbus_code              = MEDIA_BUS_FMT_VYUY8_1X16,
                .input_format           = SUN6I_CSI_INPUT_FMT_YUV422,
                .input_yuv_seq          = SUN6I_CSI_INPUT_YUV_SEQ_VYUY,
                .input_yuv_seq_invert   = SUN6I_CSI_INPUT_YUV_SEQ_UYVY,
        },
        /* Compressed */
        {
                .mbus_code              = MEDIA_BUS_FMT_JPEG_1X8,
                .input_format           = SUN6I_CSI_INPUT_FMT_RAW,
        },
};

const struct sun6i_csi_bridge_format *
sun6i_csi_bridge_format_find(u32 mbus_code)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(sun6i_csi_bridge_formats); i++)
                if (sun6i_csi_bridge_formats[i].mbus_code == mbus_code)
                        return &sun6i_csi_bridge_formats[i];

        return NULL;
}

/* Bridge */

static void sun6i_csi_bridge_irq_enable(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;

        regmap_write(regmap, SUN6I_CSI_CH_INT_EN_REG,
                     SUN6I_CSI_CH_INT_EN_VS |
                     SUN6I_CSI_CH_INT_EN_HB_OF |
                     SUN6I_CSI_CH_INT_EN_FIFO2_OF |
                     SUN6I_CSI_CH_INT_EN_FIFO1_OF |
                     SUN6I_CSI_CH_INT_EN_FIFO0_OF |
                     SUN6I_CSI_CH_INT_EN_FD |
                     SUN6I_CSI_CH_INT_EN_CD);
}

static void sun6i_csi_bridge_irq_disable(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;

        regmap_write(regmap, SUN6I_CSI_CH_INT_EN_REG, 0);
}

static void sun6i_csi_bridge_irq_clear(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;

        regmap_write(regmap, SUN6I_CSI_CH_INT_EN_REG, 0);
        regmap_write(regmap, SUN6I_CSI_CH_INT_STA_REG,
                     SUN6I_CSI_CH_INT_STA_CLEAR);
}

static void sun6i_csi_bridge_enable(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;

        regmap_update_bits(regmap, SUN6I_CSI_EN_REG, SUN6I_CSI_EN_CSI_EN,
                           SUN6I_CSI_EN_CSI_EN);

        regmap_update_bits(regmap, SUN6I_CSI_CAP_REG, SUN6I_CSI_CAP_VCAP_ON,
                           SUN6I_CSI_CAP_VCAP_ON);
}

static void sun6i_csi_bridge_disable(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;

        regmap_update_bits(regmap, SUN6I_CSI_CAP_REG, SUN6I_CSI_CAP_VCAP_ON, 0);
        regmap_update_bits(regmap, SUN6I_CSI_EN_REG, SUN6I_CSI_EN_CSI_EN, 0);
}

static void
sun6i_csi_bridge_configure_parallel(struct sun6i_csi_device *csi_dev)
{
        struct device *dev = csi_dev->dev;
        struct regmap *regmap = csi_dev->regmap;
        struct v4l2_fwnode_endpoint *endpoint =
                &csi_dev->bridge.source_parallel.endpoint;
        unsigned char bus_width = endpoint->bus.parallel.bus_width;
        unsigned int flags = endpoint->bus.parallel.flags;
        u32 field;
        u32 value = SUN6I_CSI_IF_CFG_IF_CSI;

        sun6i_csi_bridge_format(csi_dev, NULL, &field);

        if (field == V4L2_FIELD_INTERLACED ||
            field == V4L2_FIELD_INTERLACED_TB ||
            field == V4L2_FIELD_INTERLACED_BT)
                value |= SUN6I_CSI_IF_CFG_SRC_TYPE_INTERLACED |
                         SUN6I_CSI_IF_CFG_FIELD_DT_PCLK_SHIFT(1) |
                         SUN6I_CSI_IF_CFG_FIELD_DT_FIELD_VSYNC;
        else
                value |= SUN6I_CSI_IF_CFG_SRC_TYPE_PROGRESSIVE;

        switch (endpoint->bus_type) {
        case V4L2_MBUS_PARALLEL:
                if (bus_width == 16)
                        value |= SUN6I_CSI_IF_CFG_IF_CSI_YUV_COMBINED;
                else
                        value |= SUN6I_CSI_IF_CFG_IF_CSI_YUV_RAW;

                if (flags & V4L2_MBUS_FIELD_EVEN_LOW)
                        value |= SUN6I_CSI_IF_CFG_FIELD_NEGATIVE;
                else
                        value |= SUN6I_CSI_IF_CFG_FIELD_POSITIVE;

                if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
                        value |= SUN6I_CSI_IF_CFG_VREF_POL_NEGATIVE;
                else
                        value |= SUN6I_CSI_IF_CFG_VREF_POL_POSITIVE;

                if (flags & V4L2_MBUS_HSYNC_ACTIVE_LOW)
                        value |= SUN6I_CSI_IF_CFG_HREF_POL_NEGATIVE;
                else
                        value |= SUN6I_CSI_IF_CFG_HREF_POL_POSITIVE;

                if (flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
                        value |= SUN6I_CSI_IF_CFG_CLK_POL_RISING;
                else
                        value |= SUN6I_CSI_IF_CFG_CLK_POL_FALLING;
                break;
        case V4L2_MBUS_BT656:
                if (bus_width == 16)
                        value |= SUN6I_CSI_IF_CFG_IF_CSI_BT1120;
                else
                        value |= SUN6I_CSI_IF_CFG_IF_CSI_BT656;

                if (flags & V4L2_MBUS_FIELD_EVEN_LOW)
                        value |= SUN6I_CSI_IF_CFG_FIELD_NEGATIVE;
                else
                        value |= SUN6I_CSI_IF_CFG_FIELD_POSITIVE;

                if (flags & V4L2_MBUS_PCLK_SAMPLE_FALLING)
                        value |= SUN6I_CSI_IF_CFG_CLK_POL_RISING;
                else
                        value |= SUN6I_CSI_IF_CFG_CLK_POL_FALLING;
                break;
        default:
                dev_warn(dev, "unsupported bus type: %d\n", endpoint->bus_type);
                break;
        }

        switch (bus_width) {
        case 8:
        /* 16-bit YUV formats use a doubled width in 8-bit mode. */
        case 16:
                value |= SUN6I_CSI_IF_CFG_DATA_WIDTH_8;
                break;
        case 10:
                value |= SUN6I_CSI_IF_CFG_DATA_WIDTH_10;
                break;
        case 12:
                value |= SUN6I_CSI_IF_CFG_DATA_WIDTH_12;
                break;
        default:
                dev_warn(dev, "unsupported bus width: %u\n", bus_width);
                break;
        }

        regmap_write(regmap, SUN6I_CSI_IF_CFG_REG, value);
}

static void
sun6i_csi_bridge_configure_mipi_csi2(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;
        u32 value = SUN6I_CSI_IF_CFG_IF_MIPI;
        u32 field;

        sun6i_csi_bridge_format(csi_dev, NULL, &field);

        if (field == V4L2_FIELD_INTERLACED ||
            field == V4L2_FIELD_INTERLACED_TB ||
            field == V4L2_FIELD_INTERLACED_BT)
                value |= SUN6I_CSI_IF_CFG_SRC_TYPE_INTERLACED;
        else
                value |= SUN6I_CSI_IF_CFG_SRC_TYPE_PROGRESSIVE;

        regmap_write(regmap, SUN6I_CSI_IF_CFG_REG, value);
}

static void sun6i_csi_bridge_configure_format(struct sun6i_csi_device *csi_dev)
{
        struct regmap *regmap = csi_dev->regmap;
        bool capture_streaming = csi_dev->capture.state.streaming;
        const struct sun6i_csi_bridge_format *bridge_format;
        const struct sun6i_csi_capture_format *capture_format;
        u32 mbus_code, field, pixelformat;
        u8 input_format, input_yuv_seq, output_format;
        u32 value = 0;

        sun6i_csi_bridge_format(csi_dev, &mbus_code, &field);

        bridge_format = sun6i_csi_bridge_format_find(mbus_code);
        if (WARN_ON(!bridge_format))
                return;

        input_format = bridge_format->input_format;
        input_yuv_seq = bridge_format->input_yuv_seq;

        if (capture_streaming) {
                sun6i_csi_capture_format(csi_dev, &pixelformat, NULL);

                capture_format = sun6i_csi_capture_format_find(pixelformat);
                if (WARN_ON(!capture_format))
                        return;

                if (capture_format->input_format_raw)
                        input_format = SUN6I_CSI_INPUT_FMT_RAW;

                if (capture_format->input_yuv_seq_invert)
                        input_yuv_seq = bridge_format->input_yuv_seq_invert;

                if (field == V4L2_FIELD_INTERLACED ||
                    field == V4L2_FIELD_INTERLACED_TB ||
                    field == V4L2_FIELD_INTERLACED_BT)
                        output_format = capture_format->output_format_field;
                else
                        output_format = capture_format->output_format_frame;

                value |= SUN6I_CSI_CH_CFG_OUTPUT_FMT(output_format);
        }

        value |= SUN6I_CSI_CH_CFG_INPUT_FMT(input_format);
        value |= SUN6I_CSI_CH_CFG_INPUT_YUV_SEQ(input_yuv_seq);

        if (field == V4L2_FIELD_TOP)
                value |= SUN6I_CSI_CH_CFG_FIELD_SEL_FIELD0;
        else if (field == V4L2_FIELD_BOTTOM)
                value |= SUN6I_CSI_CH_CFG_FIELD_SEL_FIELD1;
        else
                value |= SUN6I_CSI_CH_CFG_FIELD_SEL_EITHER;

        regmap_write(regmap, SUN6I_CSI_CH_CFG_REG, value);
}

static void sun6i_csi_bridge_configure(struct sun6i_csi_device *csi_dev,
                                       struct sun6i_csi_bridge_source *source)
{
        struct sun6i_csi_bridge *bridge = &csi_dev->bridge;

        if (source == &bridge->source_parallel)
                sun6i_csi_bridge_configure_parallel(csi_dev);
        else
                sun6i_csi_bridge_configure_mipi_csi2(csi_dev);

        sun6i_csi_bridge_configure_format(csi_dev);
}

/* V4L2 Subdev */

static int sun6i_csi_bridge_s_stream(struct v4l2_subdev *subdev, int on)
{
        struct sun6i_csi_device *csi_dev = v4l2_get_subdevdata(subdev);
        struct sun6i_csi_bridge *bridge = &csi_dev->bridge;
        struct media_pad *local_pad = &bridge->pads[SUN6I_CSI_BRIDGE_PAD_SINK];
        bool capture_streaming = csi_dev->capture.state.streaming;
        struct device *dev = csi_dev->dev;
        struct sun6i_csi_bridge_source *source;
        struct v4l2_subdev *source_subdev;
        struct media_pad *remote_pad;
        int ret;

        /* Source */

        remote_pad = media_pad_remote_pad_unique(local_pad);
        if (IS_ERR(remote_pad)) {
                dev_err(dev,
                        "zero or more than a single source connected to the bridge\n");
                return PTR_ERR(remote_pad);
        }

        source_subdev = media_entity_to_v4l2_subdev(remote_pad->entity);

        if (source_subdev == bridge->source_parallel.subdev)
                source = &bridge->source_parallel;
        else
                source = &bridge->source_mipi_csi2;

        if (!on) {
                v4l2_subdev_call(source_subdev, video, s_stream, 0);
                ret = 0;
                goto disable;
        }

        /* PM */

        ret = pm_runtime_resume_and_get(dev);
        if (ret < 0)
                return ret;

        /* Clear */

        sun6i_csi_bridge_irq_clear(csi_dev);

        /* Configure */

        sun6i_csi_bridge_configure(csi_dev, source);

        if (capture_streaming)
                sun6i_csi_capture_configure(csi_dev);

        /* State Update */

        if (capture_streaming)
                sun6i_csi_capture_state_update(csi_dev);

        /* Enable */

        if (capture_streaming)
                sun6i_csi_bridge_irq_enable(csi_dev);

        sun6i_csi_bridge_enable(csi_dev);

        ret = v4l2_subdev_call(source_subdev, video, s_stream, 1);
        if (ret && ret != -ENOIOCTLCMD)
                goto disable;

        return 0;

disable:
        if (capture_streaming)
                sun6i_csi_bridge_irq_disable(csi_dev);

        sun6i_csi_bridge_disable(csi_dev);

        pm_runtime_put(dev);

        return ret;
}

static const struct v4l2_subdev_video_ops sun6i_csi_bridge_video_ops = {
        .s_stream       = sun6i_csi_bridge_s_stream,
};

static void
sun6i_csi_bridge_mbus_format_prepare(struct v4l2_mbus_framefmt *mbus_format)
{
        if (!sun6i_csi_bridge_format_find(mbus_format->code))
                mbus_format->code = sun6i_csi_bridge_formats[0].mbus_code;

        mbus_format->field = V4L2_FIELD_NONE;
        mbus_format->colorspace = V4L2_COLORSPACE_RAW;
        mbus_format->quantization = V4L2_QUANTIZATION_DEFAULT;
        mbus_format->xfer_func = V4L2_XFER_FUNC_DEFAULT;
}

static int sun6i_csi_bridge_init_state(struct v4l2_subdev *subdev,
                                       struct v4l2_subdev_state *state)
{
        struct sun6i_csi_device *csi_dev = v4l2_get_subdevdata(subdev);
        unsigned int pad = SUN6I_CSI_BRIDGE_PAD_SINK;
        struct v4l2_mbus_framefmt *mbus_format =
                v4l2_subdev_state_get_format(state, pad);
        struct mutex *lock = &csi_dev->bridge.lock;

        mutex_lock(lock);

        mbus_format->code = sun6i_csi_bridge_formats[0].mbus_code;
        mbus_format->width = 1280;
        mbus_format->height = 720;

        sun6i_csi_bridge_mbus_format_prepare(mbus_format);

        mutex_unlock(lock);

        return 0;
}

static int
sun6i_csi_bridge_enum_mbus_code(struct v4l2_subdev *subdev,
                                struct v4l2_subdev_state *state,
                                struct v4l2_subdev_mbus_code_enum *code_enum)
{
        if (code_enum->index >= ARRAY_SIZE(sun6i_csi_bridge_formats))
                return -EINVAL;

        code_enum->code = sun6i_csi_bridge_formats[code_enum->index].mbus_code;

        return 0;
}

static int sun6i_csi_bridge_get_fmt(struct v4l2_subdev *subdev,
                                    struct v4l2_subdev_state *state,
                                    struct v4l2_subdev_format *format)
{
        struct sun6i_csi_device *csi_dev = v4l2_get_subdevdata(subdev);
        struct v4l2_mbus_framefmt *mbus_format = &format->format;
        struct mutex *lock = &csi_dev->bridge.lock;

        mutex_lock(lock);

        if (format->which == V4L2_SUBDEV_FORMAT_TRY)
                *mbus_format = *v4l2_subdev_state_get_format(state,
                                                             format->pad);
        else
                *mbus_format = csi_dev->bridge.mbus_format;

        mutex_unlock(lock);

        return 0;
}

static int sun6i_csi_bridge_set_fmt(struct v4l2_subdev *subdev,
                                    struct v4l2_subdev_state *state,
                                    struct v4l2_subdev_format *format)
{
        struct sun6i_csi_device *csi_dev = v4l2_get_subdevdata(subdev);
        struct v4l2_mbus_framefmt *mbus_format = &format->format;
        struct mutex *lock = &csi_dev->bridge.lock;

        mutex_lock(lock);

        sun6i_csi_bridge_mbus_format_prepare(mbus_format);

        if (format->which == V4L2_SUBDEV_FORMAT_TRY)
                *v4l2_subdev_state_get_format(state, format->pad) =
                        *mbus_format;
        else
                csi_dev->bridge.mbus_format = *mbus_format;

        mutex_unlock(lock);

        return 0;
}

static const struct v4l2_subdev_pad_ops sun6i_csi_bridge_pad_ops = {
        .enum_mbus_code = sun6i_csi_bridge_enum_mbus_code,
        .get_fmt        = sun6i_csi_bridge_get_fmt,
        .set_fmt        = sun6i_csi_bridge_set_fmt,
};

static const struct v4l2_subdev_ops sun6i_csi_bridge_subdev_ops = {
        .video  = &sun6i_csi_bridge_video_ops,
        .pad    = &sun6i_csi_bridge_pad_ops,
};

static const struct v4l2_subdev_internal_ops sun6i_csi_bridge_internal_ops = {
        .init_state     = sun6i_csi_bridge_init_state,
};

/* Media Entity */

static const struct media_entity_operations sun6i_csi_bridge_entity_ops = {
        .link_validate  = v4l2_subdev_link_validate,
};

/* V4L2 Async */

static int sun6i_csi_bridge_link(struct sun6i_csi_device *csi_dev,
                                 int sink_pad_index,
                                 struct v4l2_subdev *remote_subdev,
                                 bool enabled)
{
        struct device *dev = csi_dev->dev;
        struct v4l2_subdev *subdev = &csi_dev->bridge.subdev;
        struct media_entity *sink_entity = &subdev->entity;
        struct media_entity *source_entity = &remote_subdev->entity;
        int source_pad_index;
        int ret;

        /* Get the first remote source pad. */
        ret = media_entity_get_fwnode_pad(source_entity, remote_subdev->fwnode,
                                          MEDIA_PAD_FL_SOURCE);
        if (ret < 0) {
                dev_err(dev, "missing source pad in external entity %s\n",
                        source_entity->name);
                return -EINVAL;
        }

        source_pad_index = ret;

        dev_dbg(dev, "creating %s:%u -> %s:%u link\n", source_entity->name,
                source_pad_index, sink_entity->name, sink_pad_index);

        ret = media_create_pad_link(source_entity, source_pad_index,
                                    sink_entity, sink_pad_index,
                                    enabled ? MEDIA_LNK_FL_ENABLED : 0);
        if (ret < 0) {
                dev_err(dev, "failed to create %s:%u -> %s:%u link\n",
                        source_entity->name, source_pad_index,
                        sink_entity->name, sink_pad_index);
                return ret;
        }

        return 0;
}

static int
sun6i_csi_bridge_notifier_bound(struct v4l2_async_notifier *notifier,
                                struct v4l2_subdev *remote_subdev,
                                struct v4l2_async_connection *async_subdev)
{
        struct sun6i_csi_device *csi_dev =
                container_of(notifier, struct sun6i_csi_device,
                             bridge.notifier);
        struct sun6i_csi_bridge_async_subdev *bridge_async_subdev =
                container_of(async_subdev, struct sun6i_csi_bridge_async_subdev,
                             async_subdev);
        struct sun6i_csi_bridge *bridge = &csi_dev->bridge;
        struct sun6i_csi_bridge_source *source = bridge_async_subdev->source;
        bool enabled = false;
        int ret;

        switch (source->endpoint.base.port) {
        case SUN6I_CSI_PORT_PARALLEL:
                enabled = true;
                break;
        case SUN6I_CSI_PORT_MIPI_CSI2:
                enabled = !bridge->source_parallel.expected;
                break;
        default:
                return -EINVAL;
        }

        source->subdev = remote_subdev;

        if (csi_dev->isp_available) {
                /*
                 * Hook to the first available remote subdev to get v4l2 and
                 * media devices and register the capture device then.
                 */
                ret = sun6i_csi_isp_complete(csi_dev, remote_subdev->v4l2_dev);
                if (ret)
                        return ret;
        }

        return sun6i_csi_bridge_link(csi_dev, SUN6I_CSI_BRIDGE_PAD_SINK,
                                     remote_subdev, enabled);
}

static int
sun6i_csi_bridge_notifier_complete(struct v4l2_async_notifier *notifier)
{
        struct sun6i_csi_device *csi_dev =
                container_of(notifier, struct sun6i_csi_device,
                             bridge.notifier);
        struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;

        if (csi_dev->isp_available)
                return 0;

        return v4l2_device_register_subdev_nodes(v4l2_dev);
}

static const struct v4l2_async_notifier_operations
sun6i_csi_bridge_notifier_ops = {
        .bound          = sun6i_csi_bridge_notifier_bound,
        .complete       = sun6i_csi_bridge_notifier_complete,
};

/* Bridge */

static int sun6i_csi_bridge_source_setup(struct sun6i_csi_device *csi_dev,
                                         struct sun6i_csi_bridge_source *source,
                                         u32 port,
                                         enum v4l2_mbus_type *bus_types)
{
        struct device *dev = csi_dev->dev;
        struct v4l2_async_notifier *notifier = &csi_dev->bridge.notifier;
        struct v4l2_fwnode_endpoint *endpoint = &source->endpoint;
        struct sun6i_csi_bridge_async_subdev *bridge_async_subdev;
        struct fwnode_handle *handle;
        int ret;

        handle = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), port, 0, 0);
        if (!handle)
                return -ENODEV;

        ret = v4l2_fwnode_endpoint_parse(handle, endpoint);
        if (ret)
                goto complete;

        if (bus_types) {
                bool valid = false;
                unsigned int i;

                for (i = 0; bus_types[i] != V4L2_MBUS_INVALID; i++) {
                        if (endpoint->bus_type == bus_types[i]) {
                                valid = true;
                                break;
                        }
                }

                if (!valid) {
                        dev_err(dev, "unsupported bus type for port %d\n",
                                port);
                        ret = -EINVAL;
                        goto complete;
                }
        }

        bridge_async_subdev =
                v4l2_async_nf_add_fwnode_remote(notifier, handle,
                                                struct
                                                sun6i_csi_bridge_async_subdev);
        if (IS_ERR(bridge_async_subdev)) {
                ret = PTR_ERR(bridge_async_subdev);
                goto complete;
        }

        bridge_async_subdev->source = source;

        source->expected = true;

complete:
        fwnode_handle_put(handle);

        return ret;
}

int sun6i_csi_bridge_setup(struct sun6i_csi_device *csi_dev)
{
        struct device *dev = csi_dev->dev;
        struct sun6i_csi_bridge *bridge = &csi_dev->bridge;
        struct v4l2_device *v4l2_dev = csi_dev->v4l2_dev;
        struct v4l2_subdev *subdev = &bridge->subdev;
        struct v4l2_async_notifier *notifier = &bridge->notifier;
        struct media_pad *pads = bridge->pads;
        enum v4l2_mbus_type parallel_mbus_types[] = {
                V4L2_MBUS_PARALLEL,
                V4L2_MBUS_BT656,
                V4L2_MBUS_INVALID
        };
        int ret;

        mutex_init(&bridge->lock);

        /* V4L2 Subdev */

        v4l2_subdev_init(subdev, &sun6i_csi_bridge_subdev_ops);
        subdev->internal_ops = &sun6i_csi_bridge_internal_ops;
        strscpy(subdev->name, SUN6I_CSI_BRIDGE_NAME, sizeof(subdev->name));
        subdev->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
        subdev->owner = THIS_MODULE;
        subdev->dev = dev;

        v4l2_set_subdevdata(subdev, csi_dev);

        /* Media Entity */

        subdev->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
        subdev->entity.ops = &sun6i_csi_bridge_entity_ops;

        /* Media Pads */

        pads[SUN6I_CSI_BRIDGE_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
        pads[SUN6I_CSI_BRIDGE_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE |
                                                  MEDIA_PAD_FL_MUST_CONNECT;

        ret = media_entity_pads_init(&subdev->entity,
                                     SUN6I_CSI_BRIDGE_PAD_COUNT, pads);
        if (ret < 0)
                return ret;

        /* V4L2 Subdev */

        if (csi_dev->isp_available)
                ret = v4l2_async_register_subdev(subdev);
        else
                ret = v4l2_device_register_subdev(v4l2_dev, subdev);

        if (ret) {
                dev_err(dev, "failed to register v4l2 subdev: %d\n", ret);
                goto error_media_entity;
        }

        /* V4L2 Async */

        if (csi_dev->isp_available)
                v4l2_async_subdev_nf_init(notifier, subdev);
        else
                v4l2_async_nf_init(notifier, v4l2_dev);
        notifier->ops = &sun6i_csi_bridge_notifier_ops;

        sun6i_csi_bridge_source_setup(csi_dev, &bridge->source_parallel,
                                      SUN6I_CSI_PORT_PARALLEL,
                                      parallel_mbus_types);
        sun6i_csi_bridge_source_setup(csi_dev, &bridge->source_mipi_csi2,
                                      SUN6I_CSI_PORT_MIPI_CSI2, NULL);

        ret = v4l2_async_nf_register(notifier);
        if (ret) {
                dev_err(dev, "failed to register v4l2 async notifier: %d\n",
                        ret);
                goto error_v4l2_async_notifier;
        }

        return 0;

error_v4l2_async_notifier:
        v4l2_async_nf_cleanup(notifier);

        if (csi_dev->isp_available)
                v4l2_async_unregister_subdev(subdev);
        else
                v4l2_device_unregister_subdev(subdev);

error_media_entity:
        media_entity_cleanup(&subdev->entity);

        return ret;
}

void sun6i_csi_bridge_cleanup(struct sun6i_csi_device *csi_dev)
{
        struct v4l2_subdev *subdev = &csi_dev->bridge.subdev;
        struct v4l2_async_notifier *notifier = &csi_dev->bridge.notifier;

        v4l2_async_nf_unregister(notifier);
        v4l2_async_nf_cleanup(notifier);

        v4l2_device_unregister_subdev(subdev);

        media_entity_cleanup(&subdev->entity);
}