// SPDX-License-Identifier: GPL-2.0
/*
 * video-i2c.c - Support for I2C transport video devices
 *
 * Copyright (C) 2018 Matt Ranostay <matt.ranostay@konsulko.com>
 *
 * Supported:
 * - Panasonic AMG88xx Grid-Eye Sensors
 */

#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/hwmon.h>
#include <linux/kthread.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/videodev2.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-ioctl.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-vmalloc.h>

#define VIDEO_I2C_DRIVER        "video-i2c"

struct video_i2c_chip;

struct video_i2c_buffer {
        struct vb2_v4l2_buffer vb;
        struct list_head list;
};

struct video_i2c_data {
        struct i2c_client *client;
        const struct video_i2c_chip *chip;
        struct mutex lock;
        spinlock_t slock;
        unsigned int sequence;
        struct mutex queue_lock;

        struct v4l2_device v4l2_dev;
        struct video_device vdev;
        struct vb2_queue vb_vidq;

        struct task_struct *kthread_vid_cap;
        struct list_head vid_cap_active;
};

static const struct v4l2_fmtdesc amg88xx_format = {
        .pixelformat = V4L2_PIX_FMT_Y12,
};

static const struct v4l2_frmsize_discrete amg88xx_size = {
        .width = 8,
        .height = 8,
};

struct video_i2c_chip {
        /* video dimensions */
        const struct v4l2_fmtdesc *format;
        const struct v4l2_frmsize_discrete *size;

        /* max frames per second */
        unsigned int max_fps;

        /* pixel buffer size */
        unsigned int buffer_size;

        /* pixel size in bits */
        unsigned int bpp;

        /* xfer function */
        int (*xfer)(struct video_i2c_data *data, char *buf);

        /* hwmon init function */
        int (*hwmon_init)(struct video_i2c_data *data);
};

static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
{
        struct i2c_client *client = data->client;
        struct i2c_msg msg[2];
        u8 reg = 0x80;
        int ret;

        msg[0].addr = client->addr;
        msg[0].flags = 0;
        msg[0].len = 1;
        msg[0].buf  = (char *)&reg;

        msg[1].addr = client->addr;
        msg[1].flags = I2C_M_RD;
        msg[1].len = data->chip->buffer_size;
        msg[1].buf = (char *)buf;

        ret = i2c_transfer(client->adapter, msg, 2);

        return (ret == 2) ? 0 : -EIO;
}

#if IS_ENABLED(CONFIG_HWMON)

static const u32 amg88xx_temp_config[] = {
        HWMON_T_INPUT,
        0
};

static const struct hwmon_channel_info amg88xx_temp = {
        .type = hwmon_temp,
        .config = amg88xx_temp_config,
};

static const struct hwmon_channel_info *amg88xx_info[] = {
        &amg88xx_temp,
        NULL
};

static umode_t amg88xx_is_visible(const void *drvdata,
                                  enum hwmon_sensor_types type,
                                  u32 attr, int channel)
{
        return 0444;
}

static int amg88xx_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        struct video_i2c_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        int tmp = i2c_smbus_read_word_data(client, 0x0e);

        if (tmp < 0)
                return tmp;

        /*
         * Check for sign bit, this isn't a two's complement value but an
         * absolute temperature that needs to be inverted in the case of being
         * negative.
         */
        if (tmp & BIT(11))
                tmp = -(tmp & 0x7ff);

        *val = (tmp * 625) / 10;

        return 0;
}

static const struct hwmon_ops amg88xx_hwmon_ops = {
        .is_visible = amg88xx_is_visible,
        .read = amg88xx_read,
};

static const struct hwmon_chip_info amg88xx_chip_info = {
        .ops = &amg88xx_hwmon_ops,
        .info = amg88xx_info,
};

static int amg88xx_hwmon_init(struct video_i2c_data *data)
{
        void *hwmon = devm_hwmon_device_register_with_info(&data->client->dev,
                                "amg88xx", data, &amg88xx_chip_info, NULL);

        return PTR_ERR_OR_ZERO(hwmon);
}
#else
#define amg88xx_hwmon_init      NULL
#endif

#define AMG88XX         0

static const struct video_i2c_chip video_i2c_chip[] = {
        [AMG88XX] = {
                .size           = &amg88xx_size,
                .format         = &amg88xx_format,
                .max_fps        = 10,
                .buffer_size    = 128,
                .bpp            = 16,
                .xfer           = &amg88xx_xfer,
                .hwmon_init     = amg88xx_hwmon_init,
        },
};

static const struct v4l2_file_operations video_i2c_fops = {
        .owner          = THIS_MODULE,
        .open           = v4l2_fh_open,
        .release        = vb2_fop_release,
        .poll           = vb2_fop_poll,
        .read           = vb2_fop_read,
        .mmap           = vb2_fop_mmap,
        .unlocked_ioctl = video_ioctl2,
};

static int queue_setup(struct vb2_queue *vq,
                       unsigned int *nbuffers, unsigned int *nplanes,
                       unsigned int sizes[], struct device *alloc_devs[])
{
        struct video_i2c_data *data = vb2_get_drv_priv(vq);
        unsigned int size = data->chip->buffer_size;

        if (vq->num_buffers + *nbuffers < 2)
                *nbuffers = 2;

        if (*nplanes)
                return sizes[0] < size ? -EINVAL : 0;

        *nplanes = 1;
        sizes[0] = size;

        return 0;
}

static int buffer_prepare(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct video_i2c_data *data = vb2_get_drv_priv(vb->vb2_queue);
        unsigned int size = data->chip->buffer_size;

        if (vb2_plane_size(vb, 0) < size)
                return -EINVAL;

        vbuf->field = V4L2_FIELD_NONE;
        vb2_set_plane_payload(vb, 0, size);

        return 0;
}

static void buffer_queue(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct video_i2c_data *data = vb2_get_drv_priv(vb->vb2_queue);
        struct video_i2c_buffer *buf =
                        container_of(vbuf, struct video_i2c_buffer, vb);

        spin_lock(&data->slock);
        list_add_tail(&buf->list, &data->vid_cap_active);
        spin_unlock(&data->slock);
}

static int video_i2c_thread_vid_cap(void *priv)
{
        struct video_i2c_data *data = priv;
        unsigned int delay = msecs_to_jiffies(1000 / data->chip->max_fps);

        set_freezable();

        do {
                unsigned long start_jiffies = jiffies;
                struct video_i2c_buffer *vid_cap_buf = NULL;
                int schedule_delay;

                try_to_freeze();

                spin_lock(&data->slock);

                if (!list_empty(&data->vid_cap_active)) {
                        vid_cap_buf = list_last_entry(&data->vid_cap_active,
                                                 struct video_i2c_buffer, list);
                        list_del(&vid_cap_buf->list);
                }

                spin_unlock(&data->slock);

                if (vid_cap_buf) {
                        struct vb2_buffer *vb2_buf = &vid_cap_buf->vb.vb2_buf;
                        void *vbuf = vb2_plane_vaddr(vb2_buf, 0);
                        int ret;

                        ret = data->chip->xfer(data, vbuf);
                        vb2_buf->timestamp = ktime_get_ns();
                        vid_cap_buf->vb.sequence = data->sequence++;
                        vb2_buffer_done(vb2_buf, ret ?
                                VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
                }

                schedule_delay = delay - (jiffies - start_jiffies);

                if (time_after(jiffies, start_jiffies + delay))
                        schedule_delay = delay;

                schedule_timeout_interruptible(schedule_delay);
        } while (!kthread_should_stop());

        return 0;
}

static void video_i2c_del_list(struct vb2_queue *vq, enum vb2_buffer_state state)
{
        struct video_i2c_data *data = vb2_get_drv_priv(vq);
        struct video_i2c_buffer *buf, *tmp;

        spin_lock(&data->slock);

        list_for_each_entry_safe(buf, tmp, &data->vid_cap_active, list) {
                list_del(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, state);
        }

        spin_unlock(&data->slock);
}

static int start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct video_i2c_data *data = vb2_get_drv_priv(vq);

        if (data->kthread_vid_cap)
                return 0;

        data->sequence = 0;
        data->kthread_vid_cap = kthread_run(video_i2c_thread_vid_cap, data,
                                            "%s-vid-cap", data->v4l2_dev.name);
        if (!IS_ERR(data->kthread_vid_cap))
                return 0;

        video_i2c_del_list(vq, VB2_BUF_STATE_QUEUED);

        return PTR_ERR(data->kthread_vid_cap);
}

static void stop_streaming(struct vb2_queue *vq)
{
        struct video_i2c_data *data = vb2_get_drv_priv(vq);

        if (data->kthread_vid_cap == NULL)
                return;

        kthread_stop(data->kthread_vid_cap);
        data->kthread_vid_cap = NULL;

        video_i2c_del_list(vq, VB2_BUF_STATE_ERROR);
}

static struct vb2_ops video_i2c_video_qops = {
        .queue_setup            = queue_setup,
        .buf_prepare            = buffer_prepare,
        .buf_queue              = buffer_queue,
        .start_streaming        = start_streaming,
        .stop_streaming         = stop_streaming,
        .wait_prepare           = vb2_ops_wait_prepare,
        .wait_finish            = vb2_ops_wait_finish,
};

static int video_i2c_querycap(struct file *file, void  *priv,
                                struct v4l2_capability *vcap)
{
        struct video_i2c_data *data = video_drvdata(file);
        struct i2c_client *client = data->client;

        strscpy(vcap->driver, data->v4l2_dev.name, sizeof(vcap->driver));
        strscpy(vcap->card, data->vdev.name, sizeof(vcap->card));

        sprintf(vcap->bus_info, "I2C:%d-%d", client->adapter->nr, client->addr);

        return 0;
}

static int video_i2c_g_input(struct file *file, void *fh, unsigned int *inp)
{
        *inp = 0;

        return 0;
}

static int video_i2c_s_input(struct file *file, void *fh, unsigned int inp)
{
        return (inp > 0) ? -EINVAL : 0;
}

static int video_i2c_enum_input(struct file *file, void *fh,
                                  struct v4l2_input *vin)
{
        if (vin->index > 0)
                return -EINVAL;

        strscpy(vin->name, "Camera", sizeof(vin->name));

        vin->type = V4L2_INPUT_TYPE_CAMERA;

        return 0;
}

static int video_i2c_enum_fmt_vid_cap(struct file *file, void *fh,
                                        struct v4l2_fmtdesc *fmt)
{
        struct video_i2c_data *data = video_drvdata(file);
        enum v4l2_buf_type type = fmt->type;

        if (fmt->index > 0)
                return -EINVAL;

        *fmt = *data->chip->format;
        fmt->type = type;

        return 0;
}

static int video_i2c_enum_framesizes(struct file *file, void *fh,
                                       struct v4l2_frmsizeenum *fsize)
{
        const struct video_i2c_data *data = video_drvdata(file);
        const struct v4l2_frmsize_discrete *size = data->chip->size;

        /* currently only one frame size is allowed */
        if (fsize->index > 0)
                return -EINVAL;

        if (fsize->pixel_format != data->chip->format->pixelformat)
                return -EINVAL;

        fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
        fsize->discrete.width = size->width;
        fsize->discrete.height = size->height;

        return 0;
}

static int video_i2c_enum_frameintervals(struct file *file, void *priv,
                                           struct v4l2_frmivalenum *fe)
{
        const struct video_i2c_data *data = video_drvdata(file);
        const struct v4l2_frmsize_discrete *size = data->chip->size;

        if (fe->index > 0)
                return -EINVAL;

        if (fe->width != size->width || fe->height != size->height)
                return -EINVAL;

        fe->type = V4L2_FRMIVAL_TYPE_DISCRETE;
        fe->discrete.numerator = 1;
        fe->discrete.denominator = data->chip->max_fps;

        return 0;
}

static int video_i2c_try_fmt_vid_cap(struct file *file, void *fh,
                                       struct v4l2_format *fmt)
{
        const struct video_i2c_data *data = video_drvdata(file);
        const struct v4l2_frmsize_discrete *size = data->chip->size;
        struct v4l2_pix_format *pix = &fmt->fmt.pix;
        unsigned int bpp = data->chip->bpp / 8;

        pix->width = size->width;
        pix->height = size->height;
        pix->pixelformat = data->chip->format->pixelformat;
        pix->field = V4L2_FIELD_NONE;
        pix->bytesperline = pix->width * bpp;
        pix->sizeimage = pix->bytesperline * pix->height;
        pix->colorspace = V4L2_COLORSPACE_RAW;

        return 0;
}

static int video_i2c_s_fmt_vid_cap(struct file *file, void *fh,
                                     struct v4l2_format *fmt)
{
        struct video_i2c_data *data = video_drvdata(file);

        if (vb2_is_busy(&data->vb_vidq))
                return -EBUSY;

        return video_i2c_try_fmt_vid_cap(file, fh, fmt);
}

static int video_i2c_g_parm(struct file *filp, void *priv,
                              struct v4l2_streamparm *parm)
{
        struct video_i2c_data *data = video_drvdata(filp);

        if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        parm->parm.capture.readbuffers = 1;
        parm->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
        parm->parm.capture.timeperframe.numerator = 1;
        parm->parm.capture.timeperframe.denominator = data->chip->max_fps;

        return 0;
}

static const struct v4l2_ioctl_ops video_i2c_ioctl_ops = {
        .vidioc_querycap                = video_i2c_querycap,
        .vidioc_g_input                 = video_i2c_g_input,
        .vidioc_s_input                 = video_i2c_s_input,
        .vidioc_enum_input              = video_i2c_enum_input,
        .vidioc_enum_fmt_vid_cap        = video_i2c_enum_fmt_vid_cap,
        .vidioc_enum_framesizes         = video_i2c_enum_framesizes,
        .vidioc_enum_frameintervals     = video_i2c_enum_frameintervals,
        .vidioc_g_fmt_vid_cap           = video_i2c_try_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap           = video_i2c_s_fmt_vid_cap,
        .vidioc_g_parm                  = video_i2c_g_parm,
        .vidioc_s_parm                  = video_i2c_g_parm,
        .vidioc_try_fmt_vid_cap         = video_i2c_try_fmt_vid_cap,
        .vidioc_reqbufs                 = vb2_ioctl_reqbufs,
        .vidioc_create_bufs             = vb2_ioctl_create_bufs,
        .vidioc_prepare_buf             = vb2_ioctl_prepare_buf,
        .vidioc_querybuf                = vb2_ioctl_querybuf,
        .vidioc_qbuf                    = vb2_ioctl_qbuf,
        .vidioc_dqbuf                   = vb2_ioctl_dqbuf,
        .vidioc_streamon                = vb2_ioctl_streamon,
        .vidioc_streamoff               = vb2_ioctl_streamoff,
};

static void video_i2c_release(struct video_device *vdev)
{
        kfree(video_get_drvdata(vdev));
}

static int video_i2c_probe(struct i2c_client *client,
                             const struct i2c_device_id *id)
{
        struct video_i2c_data *data;
        struct v4l2_device *v4l2_dev;
        struct vb2_queue *queue;
        int ret = -ENODEV;

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        if (dev_fwnode(&client->dev))
                data->chip = device_get_match_data(&client->dev);
        else if (id)
                data->chip = &video_i2c_chip[id->driver_data];
        else
                goto error_free_device;

        data->client = client;
        v4l2_dev = &data->v4l2_dev;
        strscpy(v4l2_dev->name, VIDEO_I2C_DRIVER, sizeof(v4l2_dev->name));

        ret = v4l2_device_register(&client->dev, v4l2_dev);
        if (ret < 0)
                goto error_free_device;

        mutex_init(&data->lock);
        mutex_init(&data->queue_lock);

        queue = &data->vb_vidq;
        queue->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        queue->io_modes = VB2_DMABUF | VB2_MMAP | VB2_USERPTR | VB2_READ;
        queue->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
        queue->drv_priv = data;
        queue->buf_struct_size = sizeof(struct video_i2c_buffer);
        queue->min_buffers_needed = 1;
        queue->ops = &video_i2c_video_qops;
        queue->mem_ops = &vb2_vmalloc_memops;

        ret = vb2_queue_init(queue);
        if (ret < 0)
                goto error_unregister_device;

        data->vdev.queue = queue;
        data->vdev.queue->lock = &data->queue_lock;

        snprintf(data->vdev.name, sizeof(data->vdev.name),
                                 "I2C %d-%d Transport Video",
                                 client->adapter->nr, client->addr);

        data->vdev.v4l2_dev = v4l2_dev;
        data->vdev.fops = &video_i2c_fops;
        data->vdev.lock = &data->lock;
        data->vdev.ioctl_ops = &video_i2c_ioctl_ops;
        data->vdev.release = video_i2c_release;
        data->vdev.device_caps = V4L2_CAP_VIDEO_CAPTURE |
                                 V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;

        spin_lock_init(&data->slock);
        INIT_LIST_HEAD(&data->vid_cap_active);

        video_set_drvdata(&data->vdev, data);
        i2c_set_clientdata(client, data);

        if (data->chip->hwmon_init) {
                ret = data->chip->hwmon_init(data);
                if (ret < 0) {
                        dev_warn(&client->dev,
                                 "failed to register hwmon device\n");
                }
        }

        ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
        if (ret < 0)
                goto error_unregister_device;

        return 0;

error_unregister_device:
        v4l2_device_unregister(v4l2_dev);
        mutex_destroy(&data->lock);
        mutex_destroy(&data->queue_lock);

error_free_device:
        kfree(data);

        return ret;
}

static int video_i2c_remove(struct i2c_client *client)
{
        struct video_i2c_data *data = i2c_get_clientdata(client);

        video_unregister_device(&data->vdev);
        v4l2_device_unregister(&data->v4l2_dev);

        mutex_destroy(&data->lock);
        mutex_destroy(&data->queue_lock);

        return 0;
}

static const struct i2c_device_id video_i2c_id_table[] = {
        { "amg88xx", AMG88XX },
        {}
};
MODULE_DEVICE_TABLE(i2c, video_i2c_id_table);

static const struct of_device_id video_i2c_of_match[] = {
        { .compatible = "panasonic,amg88xx", .data = &video_i2c_chip[AMG88XX] },
        {}
};
MODULE_DEVICE_TABLE(of, video_i2c_of_match);

static struct i2c_driver video_i2c_driver = {
        .driver = {
                .name   = VIDEO_I2C_DRIVER,
                .of_match_table = video_i2c_of_match,
        },
        .probe          = video_i2c_probe,
        .remove         = video_i2c_remove,
        .id_table       = video_i2c_id_table,
};

module_i2c_driver(video_i2c_driver);

MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("I2C transport video support");
MODULE_LICENSE("GPL v2");