// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for STM32 Digital Camera Memory Interface
 *
 * Copyright (C) STMicroelectronics SA 2017
 * Authors: Yannick Fertre <yannick.fertre@st.com>
 *          Hugues Fruchet <hugues.fruchet@st.com>
 *          for STMicroelectronics.
 *
 * This driver is based on atmel_isi.c
 *
 */

#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/videodev2.h>

#include <media/v4l2-ctrls.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-image-sizes.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-rect.h>
#include <media/videobuf2-dma-contig.h>

#define DRV_NAME "stm32-dcmi"

/* Registers offset for DCMI */
#define DCMI_CR         0x00 /* Control Register */
#define DCMI_SR         0x04 /* Status Register */
#define DCMI_RIS        0x08 /* Raw Interrupt Status register */
#define DCMI_IER        0x0C /* Interrupt Enable Register */
#define DCMI_MIS        0x10 /* Masked Interrupt Status register */
#define DCMI_ICR        0x14 /* Interrupt Clear Register */
#define DCMI_ESCR       0x18 /* Embedded Synchronization Code Register */
#define DCMI_ESUR       0x1C /* Embedded Synchronization Unmask Register */
#define DCMI_CWSTRT     0x20 /* Crop Window STaRT */
#define DCMI_CWSIZE     0x24 /* Crop Window SIZE */
#define DCMI_DR         0x28 /* Data Register */
#define DCMI_IDR        0x2C /* IDentifier Register */

/* Bits definition for control register (DCMI_CR) */
#define CR_CAPTURE      BIT(0)
#define CR_CM           BIT(1)
#define CR_CROP         BIT(2)
#define CR_JPEG         BIT(3)
#define CR_ESS          BIT(4)
#define CR_PCKPOL       BIT(5)
#define CR_HSPOL        BIT(6)
#define CR_VSPOL        BIT(7)
#define CR_FCRC_0       BIT(8)
#define CR_FCRC_1       BIT(9)
#define CR_EDM_0        BIT(10)
#define CR_EDM_1        BIT(11)
#define CR_ENABLE       BIT(14)

/* Bits definition for status register (DCMI_SR) */
#define SR_HSYNC        BIT(0)
#define SR_VSYNC        BIT(1)
#define SR_FNE          BIT(2)

/*
 * Bits definition for interrupt registers
 * (DCMI_RIS, DCMI_IER, DCMI_MIS, DCMI_ICR)
 */
#define IT_FRAME        BIT(0)
#define IT_OVR          BIT(1)
#define IT_ERR          BIT(2)
#define IT_VSYNC        BIT(3)
#define IT_LINE         BIT(4)

enum state {
        STOPPED = 0,
        WAIT_FOR_BUFFER,
        RUNNING,
};

#define MIN_WIDTH       16U
#define MAX_WIDTH       2592U
#define MIN_HEIGHT      16U
#define MAX_HEIGHT      2592U

#define TIMEOUT_MS      1000

#define OVERRUN_ERROR_THRESHOLD 3

struct dcmi_graph_entity {
        struct v4l2_async_subdev asd;

        struct device_node *remote_node;
        struct v4l2_subdev *source;
};

struct dcmi_format {
        u32     fourcc;
        u32     mbus_code;
        u8      bpp;
};

struct dcmi_framesize {
        u32     width;
        u32     height;
};

struct dcmi_buf {
        struct vb2_v4l2_buffer  vb;
        bool                    prepared;
        dma_addr_t              paddr;
        size_t                  size;
        struct list_head        list;
};

struct stm32_dcmi {
        /* Protects the access of variables shared within the interrupt */
        spinlock_t                      irqlock;
        struct device                   *dev;
        void __iomem                    *regs;
        struct resource                 *res;
        struct reset_control            *rstc;
        int                             sequence;
        struct list_head                buffers;
        struct dcmi_buf                 *active;

        struct v4l2_device              v4l2_dev;
        struct video_device             *vdev;
        struct v4l2_async_notifier      notifier;
        struct dcmi_graph_entity        entity;
        struct v4l2_format              fmt;
        struct v4l2_rect                crop;
        bool                            do_crop;

        const struct dcmi_format        **sd_formats;
        unsigned int                    num_of_sd_formats;
        const struct dcmi_format        *sd_format;
        struct dcmi_framesize           *sd_framesizes;
        unsigned int                    num_of_sd_framesizes;
        struct dcmi_framesize           sd_framesize;
        struct v4l2_rect                sd_bounds;

        /* Protect this data structure */
        struct mutex                    lock;
        struct vb2_queue                queue;

        struct v4l2_fwnode_bus_parallel bus;
        struct completion               complete;
        struct clk                      *mclk;
        enum state                      state;
        struct dma_chan                 *dma_chan;
        dma_cookie_t                    dma_cookie;
        u32                             misr;
        int                             errors_count;
        int                             overrun_count;
        int                             buffers_count;

        /* Ensure DMA operations atomicity */
        struct mutex                    dma_lock;

        struct media_device             mdev;
        struct media_pad                vid_cap_pad;
        struct media_pipeline           pipeline;
};

static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier *n)
{
        return container_of(n, struct stm32_dcmi, notifier);
}

static inline u32 reg_read(void __iomem *base, u32 reg)
{
        return readl_relaxed(base + reg);
}

static inline void reg_write(void __iomem *base, u32 reg, u32 val)
{
        writel_relaxed(val, base + reg);
}

static inline void reg_set(void __iomem *base, u32 reg, u32 mask)
{
        reg_write(base, reg, reg_read(base, reg) | mask);
}

static inline void reg_clear(void __iomem *base, u32 reg, u32 mask)
{
        reg_write(base, reg, reg_read(base, reg) & ~mask);
}

static int dcmi_start_capture(struct stm32_dcmi *dcmi, struct dcmi_buf *buf);

static void dcmi_buffer_done(struct stm32_dcmi *dcmi,
                             struct dcmi_buf *buf,
                             size_t bytesused,
                             int err)
{
        struct vb2_v4l2_buffer *vbuf;

        if (!buf)
                return;

        list_del_init(&buf->list);

        vbuf = &buf->vb;

        vbuf->sequence = dcmi->sequence++;
        vbuf->field = V4L2_FIELD_NONE;
        vbuf->vb2_buf.timestamp = ktime_get_ns();
        vb2_set_plane_payload(&vbuf->vb2_buf, 0, bytesused);
        vb2_buffer_done(&vbuf->vb2_buf,
                        err ? VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
        dev_dbg(dcmi->dev, "buffer[%d] done seq=%d, bytesused=%zu\n",
                vbuf->vb2_buf.index, vbuf->sequence, bytesused);

        dcmi->buffers_count++;
        dcmi->active = NULL;
}

static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
{
        struct dcmi_buf *buf;

        spin_lock_irq(&dcmi->irqlock);

        if (dcmi->state != RUNNING) {
                spin_unlock_irq(&dcmi->irqlock);
                return -EINVAL;
        }

        /* Restart a new DMA transfer with next buffer */
        if (list_empty(&dcmi->buffers)) {
                dev_dbg(dcmi->dev, "Capture restart is deferred to next buffer queueing\n");
                dcmi->state = WAIT_FOR_BUFFER;
                spin_unlock_irq(&dcmi->irqlock);
                return 0;
        }
        buf = list_entry(dcmi->buffers.next, struct dcmi_buf, list);
        dcmi->active = buf;

        spin_unlock_irq(&dcmi->irqlock);

        return dcmi_start_capture(dcmi, buf);
}

static void dcmi_dma_callback(void *param)
{
        struct stm32_dcmi *dcmi = (struct stm32_dcmi *)param;
        struct dma_tx_state state;
        enum dma_status status;
        struct dcmi_buf *buf = dcmi->active;

        spin_lock_irq(&dcmi->irqlock);

        /* Check DMA status */
        status = dmaengine_tx_status(dcmi->dma_chan, dcmi->dma_cookie, &state);

        switch (status) {
        case DMA_IN_PROGRESS:
                dev_dbg(dcmi->dev, "%s: Received DMA_IN_PROGRESS\n", __func__);
                break;
        case DMA_PAUSED:
                dev_err(dcmi->dev, "%s: Received DMA_PAUSED\n", __func__);
                break;
        case DMA_ERROR:
                dev_err(dcmi->dev, "%s: Received DMA_ERROR\n", __func__);

                /* Return buffer to V4L2 in error state */
                dcmi_buffer_done(dcmi, buf, 0, -EIO);
                break;
        case DMA_COMPLETE:
                dev_dbg(dcmi->dev, "%s: Received DMA_COMPLETE\n", __func__);

                /* Return buffer to V4L2 */
                dcmi_buffer_done(dcmi, buf, buf->size, 0);

                spin_unlock_irq(&dcmi->irqlock);

                /* Restart capture */
                if (dcmi_restart_capture(dcmi))
                        dev_err(dcmi->dev, "%s: Cannot restart capture on DMA complete\n",
                                __func__);
                return;
        default:
                dev_err(dcmi->dev, "%s: Received unknown status\n", __func__);
                break;
        }

        spin_unlock_irq(&dcmi->irqlock);
}

static int dcmi_start_dma(struct stm32_dcmi *dcmi,
                          struct dcmi_buf *buf)
{
        struct dma_async_tx_descriptor *desc = NULL;
        struct dma_slave_config config;
        int ret;

        memset(&config, 0, sizeof(config));

        config.src_addr = (dma_addr_t)dcmi->res->start + DCMI_DR;
        config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        config.dst_maxburst = 4;

        /* Configure DMA channel */
        ret = dmaengine_slave_config(dcmi->dma_chan, &config);
        if (ret < 0) {
                dev_err(dcmi->dev, "%s: DMA channel config failed (%d)\n",
                        __func__, ret);
                return ret;
        }

        /*
         * Avoid call of dmaengine_terminate_all() between
         * dmaengine_prep_slave_single() and dmaengine_submit()
         * by locking the whole DMA submission sequence
         */
        mutex_lock(&dcmi->dma_lock);

        /* Prepare a DMA transaction */
        desc = dmaengine_prep_slave_single(dcmi->dma_chan, buf->paddr,
                                           buf->size,
                                           DMA_DEV_TO_MEM,
                                           DMA_PREP_INTERRUPT);
        if (!desc) {
                dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer phy=%pad size=%zu\n",
                        __func__, &buf->paddr, buf->size);
                mutex_unlock(&dcmi->dma_lock);
                return -EINVAL;
        }

        /* Set completion callback routine for notification */
        desc->callback = dcmi_dma_callback;
        desc->callback_param = dcmi;

        /* Push current DMA transaction in the pending queue */
        dcmi->dma_cookie = dmaengine_submit(desc);
        if (dma_submit_error(dcmi->dma_cookie)) {
                dev_err(dcmi->dev, "%s: DMA submission failed\n", __func__);
                mutex_unlock(&dcmi->dma_lock);
                return -ENXIO;
        }

        mutex_unlock(&dcmi->dma_lock);

        dma_async_issue_pending(dcmi->dma_chan);

        return 0;
}

static int dcmi_start_capture(struct stm32_dcmi *dcmi, struct dcmi_buf *buf)
{
        int ret;

        if (!buf)
                return -EINVAL;

        ret = dcmi_start_dma(dcmi, buf);
        if (ret) {
                dcmi->errors_count++;
                return ret;
        }

        /* Enable capture */
        reg_set(dcmi->regs, DCMI_CR, CR_CAPTURE);

        return 0;
}

static void dcmi_set_crop(struct stm32_dcmi *dcmi)
{
        u32 size, start;

        /* Crop resolution */
        size = ((dcmi->crop.height - 1) << 16) |
                ((dcmi->crop.width << 1) - 1);
        reg_write(dcmi->regs, DCMI_CWSIZE, size);

        /* Crop start point */
        start = ((dcmi->crop.top) << 16) |
                 ((dcmi->crop.left << 1));
        reg_write(dcmi->regs, DCMI_CWSTRT, start);

        dev_dbg(dcmi->dev, "Cropping to %ux%u@%u:%u\n",
                dcmi->crop.width, dcmi->crop.height,
                dcmi->crop.left, dcmi->crop.top);

        /* Enable crop */
        reg_set(dcmi->regs, DCMI_CR, CR_CROP);
}

static void dcmi_process_jpeg(struct stm32_dcmi *dcmi)
{
        struct dma_tx_state state;
        enum dma_status status;
        struct dcmi_buf *buf = dcmi->active;

        if (!buf)
                return;

        /*
         * Because of variable JPEG buffer size sent by sensor,
         * DMA transfer never completes due to transfer size never reached.
         * In order to ensure that all the JPEG data are transferred
         * in active buffer memory, DMA is drained.
         * Then DMA tx status gives the amount of data transferred
         * to memory, which is then returned to V4L2 through the active
         * buffer payload.
         */

        /* Drain DMA */
        dmaengine_synchronize(dcmi->dma_chan);

        /* Get DMA residue to get JPEG size */
        status = dmaengine_tx_status(dcmi->dma_chan, dcmi->dma_cookie, &state);
        if (status != DMA_ERROR && state.residue < buf->size) {
                /* Return JPEG buffer to V4L2 with received JPEG buffer size */
                dcmi_buffer_done(dcmi, buf, buf->size - state.residue, 0);
        } else {
                dcmi->errors_count++;
                dev_err(dcmi->dev, "%s: Cannot get JPEG size from DMA\n",
                        __func__);
                /* Return JPEG buffer to V4L2 in ERROR state */
                dcmi_buffer_done(dcmi, buf, 0, -EIO);
        }

        /* Abort DMA operation */
        dmaengine_terminate_all(dcmi->dma_chan);

        /* Restart capture */
        if (dcmi_restart_capture(dcmi))
                dev_err(dcmi->dev, "%s: Cannot restart capture on JPEG received\n",
                        __func__);
}

static irqreturn_t dcmi_irq_thread(int irq, void *arg)
{
        struct stm32_dcmi *dcmi = arg;

        spin_lock_irq(&dcmi->irqlock);

        if (dcmi->misr & IT_OVR) {
                dcmi->overrun_count++;
                if (dcmi->overrun_count > OVERRUN_ERROR_THRESHOLD)
                        dcmi->errors_count++;
        }
        if (dcmi->misr & IT_ERR)
                dcmi->errors_count++;

        if (dcmi->sd_format->fourcc == V4L2_PIX_FMT_JPEG &&
            dcmi->misr & IT_FRAME) {
                /* JPEG received */
                spin_unlock_irq(&dcmi->irqlock);
                dcmi_process_jpeg(dcmi);
                return IRQ_HANDLED;
        }

        spin_unlock_irq(&dcmi->irqlock);
        return IRQ_HANDLED;
}

static irqreturn_t dcmi_irq_callback(int irq, void *arg)
{
        struct stm32_dcmi *dcmi = arg;
        unsigned long flags;

        spin_lock_irqsave(&dcmi->irqlock, flags);

        dcmi->misr = reg_read(dcmi->regs, DCMI_MIS);

        /* Clear interrupt */
        reg_set(dcmi->regs, DCMI_ICR, IT_FRAME | IT_OVR | IT_ERR);

        spin_unlock_irqrestore(&dcmi->irqlock, flags);

        return IRQ_WAKE_THREAD;
}

static int dcmi_queue_setup(struct vb2_queue *vq,
                            unsigned int *nbuffers,
                            unsigned int *nplanes,
                            unsigned int sizes[],
                            struct device *alloc_devs[])
{
        struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
        unsigned int size;

        size = dcmi->fmt.fmt.pix.sizeimage;

        /* Make sure the image size is large enough */
        if (*nplanes)
                return sizes[0] < size ? -EINVAL : 0;

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

        dev_dbg(dcmi->dev, "Setup queue, count=%d, size=%d\n",
                *nbuffers, size);

        return 0;
}

static int dcmi_buf_init(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct dcmi_buf *buf = container_of(vbuf, struct dcmi_buf, vb);

        INIT_LIST_HEAD(&buf->list);

        return 0;
}

static int dcmi_buf_prepare(struct vb2_buffer *vb)
{
        struct stm32_dcmi *dcmi =  vb2_get_drv_priv(vb->vb2_queue);
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct dcmi_buf *buf = container_of(vbuf, struct dcmi_buf, vb);
        unsigned long size;

        size = dcmi->fmt.fmt.pix.sizeimage;

        if (vb2_plane_size(vb, 0) < size) {
                dev_err(dcmi->dev, "%s data will not fit into plane (%lu < %lu)\n",
                        __func__, vb2_plane_size(vb, 0), size);
                return -EINVAL;
        }

        vb2_set_plane_payload(vb, 0, size);

        if (!buf->prepared) {
                /* Get memory addresses */
                buf->paddr =
                        vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
                buf->size = vb2_plane_size(&buf->vb.vb2_buf, 0);
                buf->prepared = true;

                vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size);

                dev_dbg(dcmi->dev, "buffer[%d] phy=%pad size=%zu\n",
                        vb->index, &buf->paddr, buf->size);
        }

        return 0;
}

static void dcmi_buf_queue(struct vb2_buffer *vb)
{
        struct stm32_dcmi *dcmi =  vb2_get_drv_priv(vb->vb2_queue);
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct dcmi_buf *buf = container_of(vbuf, struct dcmi_buf, vb);

        spin_lock_irq(&dcmi->irqlock);

        /* Enqueue to video buffers list */
        list_add_tail(&buf->list, &dcmi->buffers);

        if (dcmi->state == WAIT_FOR_BUFFER) {
                dcmi->state = RUNNING;
                dcmi->active = buf;

                dev_dbg(dcmi->dev, "Starting capture on buffer[%d] queued\n",
                        buf->vb.vb2_buf.index);

                spin_unlock_irq(&dcmi->irqlock);
                if (dcmi_start_capture(dcmi, buf))
                        dev_err(dcmi->dev, "%s: Cannot restart capture on overflow or error\n",
                                __func__);
                return;
        }

        spin_unlock_irq(&dcmi->irqlock);
}

static struct media_entity *dcmi_find_source(struct stm32_dcmi *dcmi)
{
        struct media_entity *entity = &dcmi->vdev->entity;
        struct media_pad *pad;

        /* Walk searching for entity having no sink */
        while (1) {
                pad = &entity->pads[0];
                if (!(pad->flags & MEDIA_PAD_FL_SINK))
                        break;

                pad = media_entity_remote_pad(pad);
                if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
                        break;

                entity = pad->entity;
        }

        return entity;
}

static int dcmi_pipeline_s_fmt(struct stm32_dcmi *dcmi,
                               struct v4l2_subdev_pad_config *pad_cfg,
                               struct v4l2_subdev_format *format)
{
        struct media_entity *entity = &dcmi->entity.source->entity;
        struct v4l2_subdev *subdev;
        struct media_pad *sink_pad = NULL;
        struct media_pad *src_pad = NULL;
        struct media_pad *pad = NULL;
        struct v4l2_subdev_format fmt = *format;
        bool found = false;
        int ret;

        /*
         * Starting from sensor subdevice, walk within
         * pipeline and set format on each subdevice
         */
        while (1) {
                unsigned int i;

                /* Search if current entity has a source pad */
                for (i = 0; i < entity->num_pads; i++) {
                        pad = &entity->pads[i];
                        if (pad->flags & MEDIA_PAD_FL_SOURCE) {
                                src_pad = pad;
                                found = true;
                                break;
                        }
                }
                if (!found)
                        break;

                subdev = media_entity_to_v4l2_subdev(entity);

                /* Propagate format on sink pad if any, otherwise source pad */
                if (sink_pad)
                        pad = sink_pad;

                dev_dbg(dcmi->dev, "\"%s\":%d pad format set to 0x%x %ux%u\n",
                        subdev->name, pad->index, format->format.code,
                        format->format.width, format->format.height);

                fmt.pad = pad->index;
                ret = v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
                if (ret < 0) {
                        dev_err(dcmi->dev, "%s: Failed to set format 0x%x %ux%u on \"%s\":%d pad (%d)\n",
                                __func__, format->format.code,
                                format->format.width, format->format.height,
                                subdev->name, pad->index, ret);
                        return ret;
                }

                if (fmt.format.code != format->format.code ||
                    fmt.format.width != format->format.width ||
                    fmt.format.height != format->format.height) {
                        dev_dbg(dcmi->dev, "\"%s\":%d pad format has been changed to 0x%x %ux%u\n",
                                subdev->name, pad->index, fmt.format.code,
                                fmt.format.width, fmt.format.height);
                }

                /* Walk to next entity */
                sink_pad = media_entity_remote_pad(src_pad);
                if (!sink_pad || !is_media_entity_v4l2_subdev(sink_pad->entity))
                        break;

                entity = sink_pad->entity;
        }
        *format = fmt;

        return 0;
}

static int dcmi_pipeline_s_stream(struct stm32_dcmi *dcmi, int state)
{
        struct media_entity *entity = &dcmi->vdev->entity;
        struct v4l2_subdev *subdev;
        struct media_pad *pad;
        int ret;

        /* Start/stop all entities within pipeline */
        while (1) {
                pad = &entity->pads[0];
                if (!(pad->flags & MEDIA_PAD_FL_SINK))
                        break;

                pad = media_entity_remote_pad(pad);
                if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
                        break;

                entity = pad->entity;
                subdev = media_entity_to_v4l2_subdev(entity);

                ret = v4l2_subdev_call(subdev, video, s_stream, state);
                if (ret < 0 && ret != -ENOIOCTLCMD) {
                        dev_err(dcmi->dev, "%s: \"%s\" failed to %s streaming (%d)\n",
                                __func__, subdev->name,
                                state ? "start" : "stop", ret);
                        return ret;
                }

                dev_dbg(dcmi->dev, "\"%s\" is %s\n",
                        subdev->name, state ? "started" : "stopped");
        }

        return 0;
}

static int dcmi_pipeline_start(struct stm32_dcmi *dcmi)
{
        return dcmi_pipeline_s_stream(dcmi, 1);
}

static void dcmi_pipeline_stop(struct stm32_dcmi *dcmi)
{
        dcmi_pipeline_s_stream(dcmi, 0);
}

static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
        struct dcmi_buf *buf, *node;
        u32 val = 0;
        int ret;

        ret = pm_runtime_get_sync(dcmi->dev);
        if (ret < 0) {
                dev_err(dcmi->dev, "%s: Failed to start streaming, cannot get sync (%d)\n",
                        __func__, ret);
                goto err_pm_put;
        }

        ret = media_pipeline_start(&dcmi->vdev->entity, &dcmi->pipeline);
        if (ret < 0) {
                dev_err(dcmi->dev, "%s: Failed to start streaming, media pipeline start error (%d)\n",
                        __func__, ret);
                goto err_pm_put;
        }

        ret = dcmi_pipeline_start(dcmi);
        if (ret)
                goto err_media_pipeline_stop;

        spin_lock_irq(&dcmi->irqlock);

        /* Set bus width */
        switch (dcmi->bus.bus_width) {
        case 14:
                val |= CR_EDM_0 | CR_EDM_1;
                break;
        case 12:
                val |= CR_EDM_1;
                break;
        case 10:
                val |= CR_EDM_0;
                break;
        default:
                /* Set bus width to 8 bits by default */
                break;
        }

        /* Set vertical synchronization polarity */
        if (dcmi->bus.flags & V4L2_MBUS_VSYNC_ACTIVE_HIGH)
                val |= CR_VSPOL;

        /* Set horizontal synchronization polarity */
        if (dcmi->bus.flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
                val |= CR_HSPOL;

        /* Set pixel clock polarity */
        if (dcmi->bus.flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
                val |= CR_PCKPOL;

        reg_write(dcmi->regs, DCMI_CR, val);

        /* Set crop */
        if (dcmi->do_crop)
                dcmi_set_crop(dcmi);

        /* Enable jpeg capture */
        if (dcmi->sd_format->fourcc == V4L2_PIX_FMT_JPEG)
                reg_set(dcmi->regs, DCMI_CR, CR_CM);/* Snapshot mode */

        /* Enable dcmi */
        reg_set(dcmi->regs, DCMI_CR, CR_ENABLE);

        dcmi->sequence = 0;
        dcmi->errors_count = 0;
        dcmi->overrun_count = 0;
        dcmi->buffers_count = 0;

        /*
         * Start transfer if at least one buffer has been queued,
         * otherwise transfer is deferred at buffer queueing
         */
        if (list_empty(&dcmi->buffers)) {
                dev_dbg(dcmi->dev, "Start streaming is deferred to next buffer queueing\n");
                dcmi->state = WAIT_FOR_BUFFER;
                spin_unlock_irq(&dcmi->irqlock);
                return 0;
        }

        buf = list_entry(dcmi->buffers.next, struct dcmi_buf, list);
        dcmi->active = buf;

        dcmi->state = RUNNING;

        dev_dbg(dcmi->dev, "Start streaming, starting capture\n");

        spin_unlock_irq(&dcmi->irqlock);
        ret = dcmi_start_capture(dcmi, buf);
        if (ret) {
                dev_err(dcmi->dev, "%s: Start streaming failed, cannot start capture\n",
                        __func__);
                goto err_pipeline_stop;
        }

        /* Enable interruptions */
        if (dcmi->sd_format->fourcc == V4L2_PIX_FMT_JPEG)
                reg_set(dcmi->regs, DCMI_IER, IT_FRAME | IT_OVR | IT_ERR);
        else
                reg_set(dcmi->regs, DCMI_IER, IT_OVR | IT_ERR);

        return 0;

err_pipeline_stop:
        dcmi_pipeline_stop(dcmi);

err_media_pipeline_stop:
        media_pipeline_stop(&dcmi->vdev->entity);

err_pm_put:
        pm_runtime_put(dcmi->dev);
        spin_lock_irq(&dcmi->irqlock);
        /*
         * Return all buffers to vb2 in QUEUED state.
         * This will give ownership back to userspace
         */
        list_for_each_entry_safe(buf, node, &dcmi->buffers, list) {
                list_del_init(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
        }
        dcmi->active = NULL;
        spin_unlock_irq(&dcmi->irqlock);

        return ret;
}

static void dcmi_stop_streaming(struct vb2_queue *vq)
{
        struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
        struct dcmi_buf *buf, *node;

        dcmi_pipeline_stop(dcmi);

        media_pipeline_stop(&dcmi->vdev->entity);

        spin_lock_irq(&dcmi->irqlock);

        /* Disable interruptions */
        reg_clear(dcmi->regs, DCMI_IER, IT_FRAME | IT_OVR | IT_ERR);

        /* Disable DCMI */
        reg_clear(dcmi->regs, DCMI_CR, CR_ENABLE);

        /* Return all queued buffers to vb2 in ERROR state */
        list_for_each_entry_safe(buf, node, &dcmi->buffers, list) {
                list_del_init(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
        }

        dcmi->active = NULL;
        dcmi->state = STOPPED;

        spin_unlock_irq(&dcmi->irqlock);

        /* Stop all pending DMA operations */
        mutex_lock(&dcmi->dma_lock);
        dmaengine_terminate_all(dcmi->dma_chan);
        mutex_unlock(&dcmi->dma_lock);

        pm_runtime_put(dcmi->dev);

        if (dcmi->errors_count)
                dev_warn(dcmi->dev, "Some errors found while streaming: errors=%d (overrun=%d), buffers=%d\n",
                         dcmi->errors_count, dcmi->overrun_count,
                         dcmi->buffers_count);
        dev_dbg(dcmi->dev, "Stop streaming, errors=%d (overrun=%d), buffers=%d\n",
                dcmi->errors_count, dcmi->overrun_count,
                dcmi->buffers_count);
}

static const struct vb2_ops dcmi_video_qops = {
        .queue_setup            = dcmi_queue_setup,
        .buf_init               = dcmi_buf_init,
        .buf_prepare            = dcmi_buf_prepare,
        .buf_queue              = dcmi_buf_queue,
        .start_streaming        = dcmi_start_streaming,
        .stop_streaming         = dcmi_stop_streaming,
        .wait_prepare           = vb2_ops_wait_prepare,
        .wait_finish            = vb2_ops_wait_finish,
};

static int dcmi_g_fmt_vid_cap(struct file *file, void *priv,
                              struct v4l2_format *fmt)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        *fmt = dcmi->fmt;

        return 0;
}

static const struct dcmi_format *find_format_by_fourcc(struct stm32_dcmi *dcmi,
                                                       unsigned int fourcc)
{
        unsigned int num_formats = dcmi->num_of_sd_formats;
        const struct dcmi_format *fmt;
        unsigned int i;

        for (i = 0; i < num_formats; i++) {
                fmt = dcmi->sd_formats[i];
                if (fmt->fourcc == fourcc)
                        return fmt;
        }

        return NULL;
}

static void __find_outer_frame_size(struct stm32_dcmi *dcmi,
                                    struct v4l2_pix_format *pix,
                                    struct dcmi_framesize *framesize)
{
        struct dcmi_framesize *match = NULL;
        unsigned int i;
        unsigned int min_err = UINT_MAX;

        for (i = 0; i < dcmi->num_of_sd_framesizes; i++) {
                struct dcmi_framesize *fsize = &dcmi->sd_framesizes[i];
                int w_err = (fsize->width - pix->width);
                int h_err = (fsize->height - pix->height);
                int err = w_err + h_err;

                if (w_err >= 0 && h_err >= 0 && err < min_err) {
                        min_err = err;
                        match = fsize;
                }
        }
        if (!match)
                match = &dcmi->sd_framesizes[0];

        *framesize = *match;
}

static int dcmi_try_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f,
                        const struct dcmi_format **sd_format,
                        struct dcmi_framesize *sd_framesize)
{
        const struct dcmi_format *sd_fmt;
        struct dcmi_framesize sd_fsize;
        struct v4l2_pix_format *pix = &f->fmt.pix;
        struct v4l2_subdev_pad_config pad_cfg;
        struct v4l2_subdev_format format = {
                .which = V4L2_SUBDEV_FORMAT_TRY,
        };
        bool do_crop;
        int ret;

        sd_fmt = find_format_by_fourcc(dcmi, pix->pixelformat);
        if (!sd_fmt) {
                if (!dcmi->num_of_sd_formats)
                        return -ENODATA;

                sd_fmt = dcmi->sd_formats[dcmi->num_of_sd_formats - 1];
                pix->pixelformat = sd_fmt->fourcc;
        }

        /* Limit to hardware capabilities */
        pix->width = clamp(pix->width, MIN_WIDTH, MAX_WIDTH);
        pix->height = clamp(pix->height, MIN_HEIGHT, MAX_HEIGHT);

        /* No crop if JPEG is requested */
        do_crop = dcmi->do_crop && (pix->pixelformat != V4L2_PIX_FMT_JPEG);

        if (do_crop && dcmi->num_of_sd_framesizes) {
                struct dcmi_framesize outer_sd_fsize;
                /*
                 * If crop is requested and sensor have discrete frame sizes,
                 * select the frame size that is just larger than request
                 */
                __find_outer_frame_size(dcmi, pix, &outer_sd_fsize);
                pix->width = outer_sd_fsize.width;
                pix->height = outer_sd_fsize.height;
        }

        v4l2_fill_mbus_format(&format.format, pix, sd_fmt->mbus_code);
        ret = v4l2_subdev_call(dcmi->entity.source, pad, set_fmt,
                               &pad_cfg, &format);
        if (ret < 0)
                return ret;

        /* Update pix regarding to what sensor can do */
        v4l2_fill_pix_format(pix, &format.format);

        /* Save resolution that sensor can actually do */
        sd_fsize.width = pix->width;
        sd_fsize.height = pix->height;

        if (do_crop) {
                struct v4l2_rect c = dcmi->crop;
                struct v4l2_rect max_rect;

                /*
                 * Adjust crop by making the intersection between
                 * format resolution request and crop request
                 */
                max_rect.top = 0;
                max_rect.left = 0;
                max_rect.width = pix->width;
                max_rect.height = pix->height;
                v4l2_rect_map_inside(&c, &max_rect);
                c.top  = clamp_t(s32, c.top, 0, pix->height - c.height);
                c.left = clamp_t(s32, c.left, 0, pix->width - c.width);
                dcmi->crop = c;

                /* Adjust format resolution request to crop */
                pix->width = dcmi->crop.width;
                pix->height = dcmi->crop.height;
        }

        pix->field = V4L2_FIELD_NONE;
        pix->bytesperline = pix->width * sd_fmt->bpp;
        pix->sizeimage = pix->bytesperline * pix->height;

        if (sd_format)
                *sd_format = sd_fmt;
        if (sd_framesize)
                *sd_framesize = sd_fsize;

        return 0;
}

static int dcmi_set_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f)
{
        struct v4l2_subdev_format format = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };
        const struct dcmi_format *sd_format;
        struct dcmi_framesize sd_framesize;
        struct v4l2_mbus_framefmt *mf = &format.format;
        struct v4l2_pix_format *pix = &f->fmt.pix;
        int ret;

        /*
         * Try format, fmt.width/height could have been changed
         * to match sensor capability or crop request
         * sd_format & sd_framesize will contain what subdev
         * can do for this request.
         */
        ret = dcmi_try_fmt(dcmi, f, &sd_format, &sd_framesize);
        if (ret)
                return ret;

        /* Disable crop if JPEG is requested */
        if (pix->pixelformat == V4L2_PIX_FMT_JPEG)
                dcmi->do_crop = false;

        /* pix to mbus format */
        v4l2_fill_mbus_format(mf, pix,
                              sd_format->mbus_code);
        mf->width = sd_framesize.width;
        mf->height = sd_framesize.height;

        ret = dcmi_pipeline_s_fmt(dcmi, NULL, &format);
        if (ret < 0)
                return ret;

        dev_dbg(dcmi->dev, "Sensor format set to 0x%x %ux%u\n",
                mf->code, mf->width, mf->height);
        dev_dbg(dcmi->dev, "Buffer format set to %4.4s %ux%u\n",
                (char *)&pix->pixelformat,
                pix->width, pix->height);

        dcmi->fmt = *f;
        dcmi->sd_format = sd_format;
        dcmi->sd_framesize = sd_framesize;

        return 0;
}

static int dcmi_s_fmt_vid_cap(struct file *file, void *priv,
                              struct v4l2_format *f)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        if (vb2_is_streaming(&dcmi->queue))
                return -EBUSY;

        return dcmi_set_fmt(dcmi, f);
}

static int dcmi_try_fmt_vid_cap(struct file *file, void *priv,
                                struct v4l2_format *f)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        return dcmi_try_fmt(dcmi, f, NULL, NULL);
}

static int dcmi_enum_fmt_vid_cap(struct file *file, void  *priv,
                                 struct v4l2_fmtdesc *f)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        if (f->index >= dcmi->num_of_sd_formats)
                return -EINVAL;

        f->pixelformat = dcmi->sd_formats[f->index]->fourcc;
        return 0;
}

static int dcmi_get_sensor_format(struct stm32_dcmi *dcmi,
                                  struct v4l2_pix_format *pix)
{
        struct v4l2_subdev_format fmt = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };
        int ret;

        ret = v4l2_subdev_call(dcmi->entity.source, pad, get_fmt, NULL, &fmt);
        if (ret)
                return ret;

        v4l2_fill_pix_format(pix, &fmt.format);

        return 0;
}

static int dcmi_set_sensor_format(struct stm32_dcmi *dcmi,
                                  struct v4l2_pix_format *pix)
{
        const struct dcmi_format *sd_fmt;
        struct v4l2_subdev_format format = {
                .which = V4L2_SUBDEV_FORMAT_TRY,
        };
        struct v4l2_subdev_pad_config pad_cfg;
        int ret;

        sd_fmt = find_format_by_fourcc(dcmi, pix->pixelformat);
        if (!sd_fmt) {
                if (!dcmi->num_of_sd_formats)
                        return -ENODATA;

                sd_fmt = dcmi->sd_formats[dcmi->num_of_sd_formats - 1];
                pix->pixelformat = sd_fmt->fourcc;
        }

        v4l2_fill_mbus_format(&format.format, pix, sd_fmt->mbus_code);
        ret = v4l2_subdev_call(dcmi->entity.source, pad, set_fmt,
                               &pad_cfg, &format);
        if (ret < 0)
                return ret;

        return 0;
}

static int dcmi_get_sensor_bounds(struct stm32_dcmi *dcmi,
                                  struct v4l2_rect *r)
{
        struct v4l2_subdev_selection bounds = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = V4L2_SEL_TGT_CROP_BOUNDS,
        };
        unsigned int max_width, max_height, max_pixsize;
        struct v4l2_pix_format pix;
        unsigned int i;
        int ret;

        /*
         * Get sensor bounds first
         */
        ret = v4l2_subdev_call(dcmi->entity.source, pad, get_selection,
                               NULL, &bounds);
        if (!ret)
                *r = bounds.r;
        if (ret != -ENOIOCTLCMD)
                return ret;

        /*
         * If selection is not implemented,
         * fallback by enumerating sensor frame sizes
         * and take the largest one
         */
        max_width = 0;
        max_height = 0;
        max_pixsize = 0;
        for (i = 0; i < dcmi->num_of_sd_framesizes; i++) {
                struct dcmi_framesize *fsize = &dcmi->sd_framesizes[i];
                unsigned int pixsize = fsize->width * fsize->height;

                if (pixsize > max_pixsize) {
                        max_pixsize = pixsize;
                        max_width = fsize->width;
                        max_height = fsize->height;
                }
        }
        if (max_pixsize > 0) {
                r->top = 0;
                r->left = 0;
                r->width = max_width;
                r->height = max_height;
                return 0;
        }

        /*
         * If frame sizes enumeration is not implemented,
         * fallback by getting current sensor frame size
         */
        ret = dcmi_get_sensor_format(dcmi, &pix);
        if (ret)
                return ret;

        r->top = 0;
        r->left = 0;
        r->width = pix.width;
        r->height = pix.height;

        return 0;
}

static int dcmi_g_selection(struct file *file, void *fh,
                            struct v4l2_selection *s)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

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

        switch (s->target) {
        case V4L2_SEL_TGT_CROP_DEFAULT:
        case V4L2_SEL_TGT_CROP_BOUNDS:
                s->r = dcmi->sd_bounds;
                return 0;
        case V4L2_SEL_TGT_CROP:
                if (dcmi->do_crop) {
                        s->r = dcmi->crop;
                } else {
                        s->r.top = 0;
                        s->r.left = 0;
                        s->r.width = dcmi->fmt.fmt.pix.width;
                        s->r.height = dcmi->fmt.fmt.pix.height;
                }
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int dcmi_s_selection(struct file *file, void *priv,
                            struct v4l2_selection *s)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);
        struct v4l2_rect r = s->r;
        struct v4l2_rect max_rect;
        struct v4l2_pix_format pix;

        if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
            s->target != V4L2_SEL_TGT_CROP)
                return -EINVAL;

        /* Reset sensor resolution to max resolution */
        pix.pixelformat = dcmi->fmt.fmt.pix.pixelformat;
        pix.width = dcmi->sd_bounds.width;
        pix.height = dcmi->sd_bounds.height;
        dcmi_set_sensor_format(dcmi, &pix);

        /*
         * Make the intersection between
         * sensor resolution
         * and crop request
         */
        max_rect.top = 0;
        max_rect.left = 0;
        max_rect.width = pix.width;
        max_rect.height = pix.height;
        v4l2_rect_map_inside(&r, &max_rect);
        r.top  = clamp_t(s32, r.top, 0, pix.height - r.height);
        r.left = clamp_t(s32, r.left, 0, pix.width - r.width);

        if (!(r.top == dcmi->sd_bounds.top &&
              r.left == dcmi->sd_bounds.left &&
              r.width == dcmi->sd_bounds.width &&
              r.height == dcmi->sd_bounds.height)) {
                /* Crop if request is different than sensor resolution */
                dcmi->do_crop = true;
                dcmi->crop = r;
                dev_dbg(dcmi->dev, "s_selection: crop %ux%u@(%u,%u) from %ux%u\n",
                        r.width, r.height, r.left, r.top,
                        pix.width, pix.height);
        } else {
                /* Disable crop */
                dcmi->do_crop = false;
                dev_dbg(dcmi->dev, "s_selection: crop is disabled\n");
        }

        s->r = r;
        return 0;
}

static int dcmi_querycap(struct file *file, void *priv,
                         struct v4l2_capability *cap)
{
        strscpy(cap->driver, DRV_NAME, sizeof(cap->driver));
        strscpy(cap->card, "STM32 Camera Memory Interface",
                sizeof(cap->card));
        strscpy(cap->bus_info, "platform:dcmi", sizeof(cap->bus_info));
        return 0;
}

static int dcmi_enum_input(struct file *file, void *priv,
                           struct v4l2_input *i)
{
        if (i->index != 0)
                return -EINVAL;

        i->type = V4L2_INPUT_TYPE_CAMERA;
        strscpy(i->name, "Camera", sizeof(i->name));
        return 0;
}

static int dcmi_g_input(struct file *file, void *priv, unsigned int *i)
{
        *i = 0;
        return 0;
}

static int dcmi_s_input(struct file *file, void *priv, unsigned int i)
{
        if (i > 0)
                return -EINVAL;
        return 0;
}

static int dcmi_enum_framesizes(struct file *file, void *fh,
                                struct v4l2_frmsizeenum *fsize)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);
        const struct dcmi_format *sd_fmt;
        struct v4l2_subdev_frame_size_enum fse = {
                .index = fsize->index,
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };
        int ret;

        sd_fmt = find_format_by_fourcc(dcmi, fsize->pixel_format);
        if (!sd_fmt)
                return -EINVAL;

        fse.code = sd_fmt->mbus_code;

        ret = v4l2_subdev_call(dcmi->entity.source, pad, enum_frame_size,
                               NULL, &fse);
        if (ret)
                return ret;

        fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
        fsize->discrete.width = fse.max_width;
        fsize->discrete.height = fse.max_height;

        return 0;
}

static int dcmi_g_parm(struct file *file, void *priv,
                       struct v4l2_streamparm *p)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        return v4l2_g_parm_cap(video_devdata(file), dcmi->entity.source, p);
}

static int dcmi_s_parm(struct file *file, void *priv,
                       struct v4l2_streamparm *p)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);

        return v4l2_s_parm_cap(video_devdata(file), dcmi->entity.source, p);
}

static int dcmi_enum_frameintervals(struct file *file, void *fh,
                                    struct v4l2_frmivalenum *fival)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);
        const struct dcmi_format *sd_fmt;
        struct v4l2_subdev_frame_interval_enum fie = {
                .index = fival->index,
                .width = fival->width,
                .height = fival->height,
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };
        int ret;

        sd_fmt = find_format_by_fourcc(dcmi, fival->pixel_format);
        if (!sd_fmt)
                return -EINVAL;

        fie.code = sd_fmt->mbus_code;

        ret = v4l2_subdev_call(dcmi->entity.source, pad,
                               enum_frame_interval, NULL, &fie);
        if (ret)
                return ret;

        fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
        fival->discrete = fie.interval;

        return 0;
}

static const struct of_device_id stm32_dcmi_of_match[] = {
        { .compatible = "st,stm32-dcmi"},
        { /* end node */ },
};
MODULE_DEVICE_TABLE(of, stm32_dcmi_of_match);

static int dcmi_open(struct file *file)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);
        struct v4l2_subdev *sd = dcmi->entity.source;
        int ret;

        if (mutex_lock_interruptible(&dcmi->lock))
                return -ERESTARTSYS;

        ret = v4l2_fh_open(file);
        if (ret < 0)
                goto unlock;

        if (!v4l2_fh_is_singular_file(file))
                goto fh_rel;

        ret = v4l2_subdev_call(sd, core, s_power, 1);
        if (ret < 0 && ret != -ENOIOCTLCMD)
                goto fh_rel;

        ret = dcmi_set_fmt(dcmi, &dcmi->fmt);
        if (ret)
                v4l2_subdev_call(sd, core, s_power, 0);
fh_rel:
        if (ret)
                v4l2_fh_release(file);
unlock:
        mutex_unlock(&dcmi->lock);
        return ret;
}

static int dcmi_release(struct file *file)
{
        struct stm32_dcmi *dcmi = video_drvdata(file);
        struct v4l2_subdev *sd = dcmi->entity.source;
        bool fh_singular;
        int ret;

        mutex_lock(&dcmi->lock);

        fh_singular = v4l2_fh_is_singular_file(file);

        ret = _vb2_fop_release(file, NULL);

        if (fh_singular)
                v4l2_subdev_call(sd, core, s_power, 0);

        mutex_unlock(&dcmi->lock);

        return ret;
}

static const struct v4l2_ioctl_ops dcmi_ioctl_ops = {
        .vidioc_querycap                = dcmi_querycap,

        .vidioc_try_fmt_vid_cap         = dcmi_try_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap           = dcmi_g_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap           = dcmi_s_fmt_vid_cap,
        .vidioc_enum_fmt_vid_cap        = dcmi_enum_fmt_vid_cap,
        .vidioc_g_selection             = dcmi_g_selection,
        .vidioc_s_selection             = dcmi_s_selection,

        .vidioc_enum_input              = dcmi_enum_input,
        .vidioc_g_input                 = dcmi_g_input,
        .vidioc_s_input                 = dcmi_s_input,

        .vidioc_g_parm                  = dcmi_g_parm,
        .vidioc_s_parm                  = dcmi_s_parm,

        .vidioc_enum_framesizes         = dcmi_enum_framesizes,
        .vidioc_enum_frameintervals     = dcmi_enum_frameintervals,

        .vidioc_reqbufs                 = vb2_ioctl_reqbufs,
        .vidioc_create_bufs             = vb2_ioctl_create_bufs,
        .vidioc_querybuf                = vb2_ioctl_querybuf,
        .vidioc_qbuf                    = vb2_ioctl_qbuf,
        .vidioc_dqbuf                   = vb2_ioctl_dqbuf,
        .vidioc_expbuf                  = vb2_ioctl_expbuf,
        .vidioc_prepare_buf             = vb2_ioctl_prepare_buf,
        .vidioc_streamon                = vb2_ioctl_streamon,
        .vidioc_streamoff               = vb2_ioctl_streamoff,

        .vidioc_log_status              = v4l2_ctrl_log_status,
        .vidioc_subscribe_event         = v4l2_ctrl_subscribe_event,
        .vidioc_unsubscribe_event       = v4l2_event_unsubscribe,
};

static const struct v4l2_file_operations dcmi_fops = {
        .owner          = THIS_MODULE,
        .unlocked_ioctl = video_ioctl2,
        .open           = dcmi_open,
        .release        = dcmi_release,
        .poll           = vb2_fop_poll,
        .mmap           = vb2_fop_mmap,
#ifndef CONFIG_MMU
        .get_unmapped_area = vb2_fop_get_unmapped_area,
#endif
        .read           = vb2_fop_read,
};

static int dcmi_set_default_fmt(struct stm32_dcmi *dcmi)
{
        struct v4l2_format f = {
                .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
                .fmt.pix = {
                        .width          = CIF_WIDTH,
                        .height         = CIF_HEIGHT,
                        .field          = V4L2_FIELD_NONE,
                        .pixelformat    = dcmi->sd_formats[0]->fourcc,
                },
        };
        int ret;

        ret = dcmi_try_fmt(dcmi, &f, NULL, NULL);
        if (ret)
                return ret;
        dcmi->sd_format = dcmi->sd_formats[0];
        dcmi->fmt = f;
        return 0;
}

/*
 * FIXME: For the time being we only support subdevices
 * which expose RGB & YUV "parallel form" mbus code (_2X8).
 * Nevertheless, this allows to support serial source subdevices
 * and serial to parallel bridges which conform to this.
 */
static const struct dcmi_format dcmi_formats[] = {
        {
                .fourcc = V4L2_PIX_FMT_RGB565,
                .mbus_code = MEDIA_BUS_FMT_RGB565_2X8_LE,
                .bpp = 2,
        }, {
                .fourcc = V4L2_PIX_FMT_YUYV,
                .mbus_code = MEDIA_BUS_FMT_YUYV8_2X8,
                .bpp = 2,
        }, {
                .fourcc = V4L2_PIX_FMT_UYVY,
                .mbus_code = MEDIA_BUS_FMT_UYVY8_2X8,
                .bpp = 2,
        }, {
                .fourcc = V4L2_PIX_FMT_JPEG,
                .mbus_code = MEDIA_BUS_FMT_JPEG_1X8,
                .bpp = 1,
        },
};

static int dcmi_formats_init(struct stm32_dcmi *dcmi)
{
        const struct dcmi_format *sd_fmts[ARRAY_SIZE(dcmi_formats)];
        unsigned int num_fmts = 0, i, j;
        struct v4l2_subdev *subdev = dcmi->entity.source;
        struct v4l2_subdev_mbus_code_enum mbus_code = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };

        while (!v4l2_subdev_call(subdev, pad, enum_mbus_code,
                                 NULL, &mbus_code)) {
                for (i = 0; i < ARRAY_SIZE(dcmi_formats); i++) {
                        if (dcmi_formats[i].mbus_code != mbus_code.code)
                                continue;

                        /* Code supported, have we got this fourcc yet? */
                        for (j = 0; j < num_fmts; j++)
                                if (sd_fmts[j]->fourcc ==
                                                dcmi_formats[i].fourcc) {
                                        /* Already available */
                                        dev_dbg(dcmi->dev, "Skipping fourcc/code: %4.4s/0x%x\n",
                                                (char *)&sd_fmts[j]->fourcc,
                                                mbus_code.code);
                                        break;
                                }
                        if (j == num_fmts) {
                                /* New */
                                sd_fmts[num_fmts++] = dcmi_formats + i;
                                dev_dbg(dcmi->dev, "Supported fourcc/code: %4.4s/0x%x\n",
                                        (char *)&sd_fmts[num_fmts - 1]->fourcc,
                                        sd_fmts[num_fmts - 1]->mbus_code);
                        }
                }
                mbus_code.index++;
        }

        if (!num_fmts)
                return -ENXIO;

        dcmi->num_of_sd_formats = num_fmts;
        dcmi->sd_formats = devm_kcalloc(dcmi->dev,
                                        num_fmts, sizeof(struct dcmi_format *),
                                        GFP_KERNEL);
        if (!dcmi->sd_formats) {
                dev_err(dcmi->dev, "Could not allocate memory\n");
                return -ENOMEM;
        }

        memcpy(dcmi->sd_formats, sd_fmts,
               num_fmts * sizeof(struct dcmi_format *));
        dcmi->sd_format = dcmi->sd_formats[0];

        return 0;
}

static int dcmi_framesizes_init(struct stm32_dcmi *dcmi)
{
        unsigned int num_fsize = 0;
        struct v4l2_subdev *subdev = dcmi->entity.source;
        struct v4l2_subdev_frame_size_enum fse = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .code = dcmi->sd_format->mbus_code,
        };
        unsigned int ret;
        unsigned int i;

        /* Allocate discrete framesizes array */
        while (!v4l2_subdev_call(subdev, pad, enum_frame_size,
                                 NULL, &fse))
                fse.index++;

        num_fsize = fse.index;
        if (!num_fsize)
                return 0;

        dcmi->num_of_sd_framesizes = num_fsize;
        dcmi->sd_framesizes = devm_kcalloc(dcmi->dev, num_fsize,
                                           sizeof(struct dcmi_framesize),
                                           GFP_KERNEL);
        if (!dcmi->sd_framesizes) {
                dev_err(dcmi->dev, "Could not allocate memory\n");
                return -ENOMEM;
        }

        /* Fill array with sensor supported framesizes */
        dev_dbg(dcmi->dev, "Sensor supports %u frame sizes:\n", num_fsize);
        for (i = 0; i < dcmi->num_of_sd_framesizes; i++) {
                fse.index = i;
                ret = v4l2_subdev_call(subdev, pad, enum_frame_size,
                                       NULL, &fse);
                if (ret)
                        return ret;
                dcmi->sd_framesizes[fse.index].width = fse.max_width;
                dcmi->sd_framesizes[fse.index].height = fse.max_height;
                dev_dbg(dcmi->dev, "%ux%u\n", fse.max_width, fse.max_height);
        }

        return 0;
}

static int dcmi_graph_notify_complete(struct v4l2_async_notifier *notifier)
{
        struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
        int ret;

        /*
         * Now that the graph is complete,
         * we search for the source subdevice
         * in order to expose it through V4L2 interface
         */
        dcmi->entity.source =
                media_entity_to_v4l2_subdev(dcmi_find_source(dcmi));
        if (!dcmi->entity.source) {
                dev_err(dcmi->dev, "Source subdevice not found\n");
                return -ENODEV;
        }

        dcmi->vdev->ctrl_handler = dcmi->entity.source->ctrl_handler;

        ret = dcmi_formats_init(dcmi);
        if (ret) {
                dev_err(dcmi->dev, "No supported mediabus format found\n");
                return ret;
        }

        ret = dcmi_framesizes_init(dcmi);
        if (ret) {
                dev_err(dcmi->dev, "Could not initialize framesizes\n");
                return ret;
        }

        ret = dcmi_get_sensor_bounds(dcmi, &dcmi->sd_bounds);
        if (ret) {
                dev_err(dcmi->dev, "Could not get sensor bounds\n");
                return ret;
        }

        ret = dcmi_set_default_fmt(dcmi);
        if (ret) {
                dev_err(dcmi->dev, "Could not set default format\n");
                return ret;
        }

        return 0;
}

static void dcmi_graph_notify_unbind(struct v4l2_async_notifier *notifier,
                                     struct v4l2_subdev *sd,
                                     struct v4l2_async_subdev *asd)
{
        struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);

        dev_dbg(dcmi->dev, "Removing %s\n", video_device_node_name(dcmi->vdev));

        /* Checks internally if vdev has been init or not */
        video_unregister_device(dcmi->vdev);
}

static int dcmi_graph_notify_bound(struct v4l2_async_notifier *notifier,
                                   struct v4l2_subdev *subdev,
                                   struct v4l2_async_subdev *asd)
{
        struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
        unsigned int ret;
        int src_pad;

        dev_dbg(dcmi->dev, "Subdev \"%s\" bound\n", subdev->name);

        /*
         * Link this sub-device to DCMI, it could be
         * a parallel camera sensor or a bridge
         */
        src_pad = media_entity_get_fwnode_pad(&subdev->entity,
                                              subdev->fwnode,
                                              MEDIA_PAD_FL_SOURCE);

        ret = media_create_pad_link(&subdev->entity, src_pad,
                                    &dcmi->vdev->entity, 0,
                                    MEDIA_LNK_FL_IMMUTABLE |
                                    MEDIA_LNK_FL_ENABLED);
        if (ret)
                dev_err(dcmi->dev, "Failed to create media pad link with subdev \"%s\"\n",
                        subdev->name);
        else
                dev_dbg(dcmi->dev, "DCMI is now linked to \"%s\"\n",
                        subdev->name);

        return ret;
}

static const struct v4l2_async_notifier_operations dcmi_graph_notify_ops = {
        .bound = dcmi_graph_notify_bound,
        .unbind = dcmi_graph_notify_unbind,
        .complete = dcmi_graph_notify_complete,
};

static int dcmi_graph_parse(struct stm32_dcmi *dcmi, struct device_node *node)
{
        struct device_node *ep = NULL;
        struct device_node *remote;

        ep = of_graph_get_next_endpoint(node, ep);
        if (!ep)
                return -EINVAL;

        remote = of_graph_get_remote_port_parent(ep);
        of_node_put(ep);
        if (!remote)
                return -EINVAL;

        /* Remote node to connect */
        dcmi->entity.remote_node = remote;
        dcmi->entity.asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
        dcmi->entity.asd.match.fwnode = of_fwnode_handle(remote);
        return 0;
}

static int dcmi_graph_init(struct stm32_dcmi *dcmi)
{
        int ret;

        /* Parse the graph to extract a list of subdevice DT nodes. */
        ret = dcmi_graph_parse(dcmi, dcmi->dev->of_node);
        if (ret < 0) {
                dev_err(dcmi->dev, "Failed to parse graph\n");
                return ret;
        }

        v4l2_async_notifier_init(&dcmi->notifier);

        ret = v4l2_async_notifier_add_subdev(&dcmi->notifier,
                                             &dcmi->entity.asd);
        if (ret) {
                dev_err(dcmi->dev, "Failed to add subdev notifier\n");
                of_node_put(dcmi->entity.remote_node);
                return ret;
        }

        dcmi->notifier.ops = &dcmi_graph_notify_ops;

        ret = v4l2_async_notifier_register(&dcmi->v4l2_dev, &dcmi->notifier);
        if (ret < 0) {
                dev_err(dcmi->dev, "Failed to register notifier\n");
                v4l2_async_notifier_cleanup(&dcmi->notifier);
                return ret;
        }

        return 0;
}

static int dcmi_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        const struct of_device_id *match = NULL;
        struct v4l2_fwnode_endpoint ep = { .bus_type = 0 };
        struct stm32_dcmi *dcmi;
        struct vb2_queue *q;
        struct dma_chan *chan;
        struct clk *mclk;
        int irq;
        int ret = 0;

        match = of_match_device(of_match_ptr(stm32_dcmi_of_match), &pdev->dev);
        if (!match) {
                dev_err(&pdev->dev, "Could not find a match in devicetree\n");
                return -ENODEV;
        }

        dcmi = devm_kzalloc(&pdev->dev, sizeof(struct stm32_dcmi), GFP_KERNEL);
        if (!dcmi)
                return -ENOMEM;

        dcmi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
        if (IS_ERR(dcmi->rstc)) {
                dev_err(&pdev->dev, "Could not get reset control\n");
                return PTR_ERR(dcmi->rstc);
        }

        /* Get bus characteristics from devicetree */
        np = of_graph_get_next_endpoint(np, NULL);
        if (!np) {
                dev_err(&pdev->dev, "Could not find the endpoint\n");
                return -ENODEV;
        }

        ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(np), &ep);
        of_node_put(np);
        if (ret) {
                dev_err(&pdev->dev, "Could not parse the endpoint\n");
                return ret;
        }

        if (ep.bus_type == V4L2_MBUS_CSI2_DPHY) {
                dev_err(&pdev->dev, "CSI bus not supported\n");
                return -ENODEV;
        }
        dcmi->bus.flags = ep.bus.parallel.flags;
        dcmi->bus.bus_width = ep.bus.parallel.bus_width;
        dcmi->bus.data_shift = ep.bus.parallel.data_shift;

        irq = platform_get_irq(pdev, 0);
        if (irq <= 0)
                return irq ? irq : -ENXIO;

        dcmi->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!dcmi->res) {
                dev_err(&pdev->dev, "Could not get resource\n");
                return -ENODEV;
        }

        dcmi->regs = devm_ioremap_resource(&pdev->dev, dcmi->res);
        if (IS_ERR(dcmi->regs)) {
                dev_err(&pdev->dev, "Could not map registers\n");
                return PTR_ERR(dcmi->regs);
        }

        ret = devm_request_threaded_irq(&pdev->dev, irq, dcmi_irq_callback,
                                        dcmi_irq_thread, IRQF_ONESHOT,
                                        dev_name(&pdev->dev), dcmi);
        if (ret) {
                dev_err(&pdev->dev, "Unable to request irq %d\n", irq);
                return ret;
        }

        mclk = devm_clk_get(&pdev->dev, "mclk");
        if (IS_ERR(mclk)) {
                if (PTR_ERR(mclk) != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "Unable to get mclk\n");
                return PTR_ERR(mclk);
        }

        chan = dma_request_chan(&pdev->dev, "tx");
        if (IS_ERR(chan)) {
                ret = PTR_ERR(chan);
                if (ret != -EPROBE_DEFER)
                        dev_err(&pdev->dev,
                                "Failed to request DMA channel: %d\n", ret);
                return ret;
        }

        spin_lock_init(&dcmi->irqlock);
        mutex_init(&dcmi->lock);
        mutex_init(&dcmi->dma_lock);
        init_completion(&dcmi->complete);
        INIT_LIST_HEAD(&dcmi->buffers);

        dcmi->dev = &pdev->dev;
        dcmi->mclk = mclk;
        dcmi->state = STOPPED;
        dcmi->dma_chan = chan;

        q = &dcmi->queue;

        dcmi->v4l2_dev.mdev = &dcmi->mdev;

        /* Initialize media device */
        strscpy(dcmi->mdev.model, DRV_NAME, sizeof(dcmi->mdev.model));
        snprintf(dcmi->mdev.bus_info, sizeof(dcmi->mdev.bus_info),
                 "platform:%s", DRV_NAME);
        dcmi->mdev.dev = &pdev->dev;
        media_device_init(&dcmi->mdev);

        /* Initialize the top-level structure */
        ret = v4l2_device_register(&pdev->dev, &dcmi->v4l2_dev);
        if (ret)
                goto err_media_device_cleanup;

        dcmi->vdev = video_device_alloc();
        if (!dcmi->vdev) {
                ret = -ENOMEM;
                goto err_device_unregister;
        }

        /* Video node */
        dcmi->vdev->fops = &dcmi_fops;
        dcmi->vdev->v4l2_dev = &dcmi->v4l2_dev;
        dcmi->vdev->queue = &dcmi->queue;
        strscpy(dcmi->vdev->name, KBUILD_MODNAME, sizeof(dcmi->vdev->name));
        dcmi->vdev->release = video_device_release;
        dcmi->vdev->ioctl_ops = &dcmi_ioctl_ops;
        dcmi->vdev->lock = &dcmi->lock;
        dcmi->vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING |
                                  V4L2_CAP_READWRITE;
        video_set_drvdata(dcmi->vdev, dcmi);

        /* Media entity pads */
        dcmi->vid_cap_pad.flags = MEDIA_PAD_FL_SINK;
        ret = media_entity_pads_init(&dcmi->vdev->entity,
                                     1, &dcmi->vid_cap_pad);
        if (ret) {
                dev_err(dcmi->dev, "Failed to init media entity pad\n");
                goto err_device_release;
        }
        dcmi->vdev->entity.flags |= MEDIA_ENT_FL_DEFAULT;

        ret = video_register_device(dcmi->vdev, VFL_TYPE_VIDEO, -1);
        if (ret) {
                dev_err(dcmi->dev, "Failed to register video device\n");
                goto err_media_entity_cleanup;
        }

        dev_dbg(dcmi->dev, "Device registered as %s\n",
                video_device_node_name(dcmi->vdev));

        /* Buffer queue */
        q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        q->io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF;
        q->lock = &dcmi->lock;
        q->drv_priv = dcmi;
        q->buf_struct_size = sizeof(struct dcmi_buf);
        q->ops = &dcmi_video_qops;
        q->mem_ops = &vb2_dma_contig_memops;
        q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
        q->min_buffers_needed = 2;
        q->dev = &pdev->dev;

        ret = vb2_queue_init(q);
        if (ret < 0) {
                dev_err(&pdev->dev, "Failed to initialize vb2 queue\n");
                goto err_media_entity_cleanup;
        }

        ret = dcmi_graph_init(dcmi);
        if (ret < 0)
                goto err_media_entity_cleanup;

        /* Reset device */
        ret = reset_control_assert(dcmi->rstc);
        if (ret) {
                dev_err(&pdev->dev, "Failed to assert the reset line\n");
                goto err_cleanup;
        }

        usleep_range(3000, 5000);

        ret = reset_control_deassert(dcmi->rstc);
        if (ret) {
                dev_err(&pdev->dev, "Failed to deassert the reset line\n");
                goto err_cleanup;
        }

        dev_info(&pdev->dev, "Probe done\n");

        platform_set_drvdata(pdev, dcmi);

        pm_runtime_enable(&pdev->dev);

        return 0;

err_cleanup:
        v4l2_async_notifier_cleanup(&dcmi->notifier);
err_media_entity_cleanup:
        media_entity_cleanup(&dcmi->vdev->entity);
err_device_release:
        video_device_release(dcmi->vdev);
err_device_unregister:
        v4l2_device_unregister(&dcmi->v4l2_dev);
err_media_device_cleanup:
        media_device_cleanup(&dcmi->mdev);
        dma_release_channel(dcmi->dma_chan);

        return ret;
}

static int dcmi_remove(struct platform_device *pdev)
{
        struct stm32_dcmi *dcmi = platform_get_drvdata(pdev);

        pm_runtime_disable(&pdev->dev);

        v4l2_async_notifier_unregister(&dcmi->notifier);
        v4l2_async_notifier_cleanup(&dcmi->notifier);
        media_entity_cleanup(&dcmi->vdev->entity);
        v4l2_device_unregister(&dcmi->v4l2_dev);
        media_device_cleanup(&dcmi->mdev);

        dma_release_channel(dcmi->dma_chan);

        return 0;
}

static __maybe_unused int dcmi_runtime_suspend(struct device *dev)
{
        struct stm32_dcmi *dcmi = dev_get_drvdata(dev);

        clk_disable_unprepare(dcmi->mclk);

        return 0;
}

static __maybe_unused int dcmi_runtime_resume(struct device *dev)
{
        struct stm32_dcmi *dcmi = dev_get_drvdata(dev);
        int ret;

        ret = clk_prepare_enable(dcmi->mclk);
        if (ret)
                dev_err(dev, "%s: Failed to prepare_enable clock\n", __func__);

        return ret;
}

static __maybe_unused int dcmi_suspend(struct device *dev)
{
        /* disable clock */
        pm_runtime_force_suspend(dev);

        /* change pinctrl state */
        pinctrl_pm_select_sleep_state(dev);

        return 0;
}

static __maybe_unused int dcmi_resume(struct device *dev)
{
        /* restore pinctl default state */
        pinctrl_pm_select_default_state(dev);

        /* clock enable */
        pm_runtime_force_resume(dev);

        return 0;
}

static const struct dev_pm_ops dcmi_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(dcmi_suspend, dcmi_resume)
        SET_RUNTIME_PM_OPS(dcmi_runtime_suspend,
                           dcmi_runtime_resume, NULL)
};

static struct platform_driver stm32_dcmi_driver = {
        .probe          = dcmi_probe,
        .remove         = dcmi_remove,
        .driver         = {
                .name = DRV_NAME,
                .of_match_table = of_match_ptr(stm32_dcmi_of_match),
                .pm = &dcmi_pm_ops,
        },
};

module_platform_driver(stm32_dcmi_driver);

MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
MODULE_AUTHOR("Hugues Fruchet <hugues.fruchet@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 Digital Camera Memory Interface driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("video");