// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 Renesas Electronics Corp.
 *
 * Driver for Renesas R-Car ISP Channel Selector
 *
 * The ISP hardware is capable of more than just channel selection, features
 * such as demosaicing, white balance control and color space conversion are
 * also possible. These more advanced features are not supported by the driver
 * due to lack of documentation.
 */

#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#include <media/mipi-csi2.h>
#include <media/v4l2-subdev.h>

#define ISPINPUTSEL0_REG                                0x0008
#define ISPINPUTSEL0_SEL_CSI0                           BIT(31)

#define ISPSTART_REG                                    0x0014
#define ISPSTART_START                                  0xffff
#define ISPSTART_STOP                                   0x0000

#define ISPPROCMODE_DT_REG(n)                           (0x1100 + (0x4 * (n)))
#define ISPPROCMODE_DT_PROC_MODE_VC3(pm)                (((pm) & 0x3f) << 24)
#define ISPPROCMODE_DT_PROC_MODE_VC2(pm)                (((pm) & 0x3f) << 16)
#define ISPPROCMODE_DT_PROC_MODE_VC1(pm)                (((pm) & 0x3f) << 8)
#define ISPPROCMODE_DT_PROC_MODE_VC0(pm)                ((pm) & 0x3f)

#define ISPCS_FILTER_ID_CH_REG(n)                       (0x3000 + (0x0100 * (n)))

#define ISPCS_DT_CODE03_CH_REG(n)                       (0x3008 + (0x100 * (n)))
#define ISPCS_DT_CODE03_EN3                             BIT(31)
#define ISPCS_DT_CODE03_DT3(dt)                         (((dt) & 0x3f) << 24)
#define ISPCS_DT_CODE03_EN2                             BIT(23)
#define ISPCS_DT_CODE03_DT2(dt)                         (((dt) & 0x3f) << 16)
#define ISPCS_DT_CODE03_EN1                             BIT(15)
#define ISPCS_DT_CODE03_DT1(dt)                         (((dt) & 0x3f) << 8)
#define ISPCS_DT_CODE03_EN0                             BIT(7)
#define ISPCS_DT_CODE03_DT0(dt)                         ((dt) & 0x3f)

struct rcar_isp_format {
        u32 code;
        unsigned int datatype;
        unsigned int procmode;
};

static const struct rcar_isp_format rcar_isp_formats[] = {
        {
                .code = MEDIA_BUS_FMT_RGB888_1X24,
                .datatype = MIPI_CSI2_DT_RGB888,
                .procmode = 0x15
        }, {
                .code = MEDIA_BUS_FMT_Y10_1X10,
                .datatype = MIPI_CSI2_DT_RAW10,
                .procmode = 0x10,
        }, {
                .code = MEDIA_BUS_FMT_UYVY8_1X16,
                .datatype = MIPI_CSI2_DT_YUV422_8B,
                .procmode = 0x0c,
        }, {
                .code = MEDIA_BUS_FMT_YUYV8_1X16,
                .datatype = MIPI_CSI2_DT_YUV422_8B,
                .procmode = 0x0c,
        }, {
                .code = MEDIA_BUS_FMT_UYVY8_2X8,
                .datatype = MIPI_CSI2_DT_YUV422_8B,
                .procmode = 0x0c,
        }, {
                .code = MEDIA_BUS_FMT_YUYV10_2X10,
                .datatype = MIPI_CSI2_DT_YUV422_8B,
                .procmode = 0x0c,
        }, {
                .code = MEDIA_BUS_FMT_SBGGR8_1X8,
                .datatype = MIPI_CSI2_DT_RAW8,
                .procmode = 0x00,
        }, {
                .code = MEDIA_BUS_FMT_SGBRG8_1X8,
                .datatype = MIPI_CSI2_DT_RAW8,
                .procmode = 0x00,
        }, {
                .code = MEDIA_BUS_FMT_SGRBG8_1X8,
                .datatype = MIPI_CSI2_DT_RAW8,
                .procmode = 0x00,
        }, {
                .code = MEDIA_BUS_FMT_SRGGB8_1X8,
                .datatype = MIPI_CSI2_DT_RAW8,
                .procmode = 0x00,
        }, {
                .code = MEDIA_BUS_FMT_SBGGR10_1X10,
                .datatype = MIPI_CSI2_DT_RAW10,
                .procmode = 0x01,
        }, {
                .code = MEDIA_BUS_FMT_SGBRG10_1X10,
                .datatype = MIPI_CSI2_DT_RAW10,
                .procmode = 0x01,
        }, {
                .code = MEDIA_BUS_FMT_SGRBG10_1X10,
                .datatype = MIPI_CSI2_DT_RAW10,
                .procmode = 0x01,
        }, {
                .code = MEDIA_BUS_FMT_SRGGB10_1X10,
                .datatype = MIPI_CSI2_DT_RAW10,
                .procmode = 0x01,
        }, {
                .code = MEDIA_BUS_FMT_SBGGR12_1X12,
                .datatype = MIPI_CSI2_DT_RAW12,
                .procmode = 0x02,
        }, {
                .code = MEDIA_BUS_FMT_SGBRG12_1X12,
                .datatype = MIPI_CSI2_DT_RAW12,
                .procmode = 0x02,
        }, {
                .code = MEDIA_BUS_FMT_SGRBG12_1X12,
                .datatype = MIPI_CSI2_DT_RAW12,
                .procmode = 0x02,
        }, {
                .code = MEDIA_BUS_FMT_SRGGB12_1X12,
                .datatype = MIPI_CSI2_DT_RAW12,
                .procmode = 0x02,
        },
};

static const struct rcar_isp_format *risp_code_to_fmt(unsigned int code)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(rcar_isp_formats); i++) {
                if (rcar_isp_formats[i].code == code)
                        return &rcar_isp_formats[i];
        }

        return NULL;
}

enum rcar_isp_input {
        RISP_CSI_INPUT0,
        RISP_CSI_INPUT1,
};

enum rcar_isp_pads {
        RCAR_ISP_SINK,
        RCAR_ISP_PORT0,
        RCAR_ISP_PORT1,
        RCAR_ISP_PORT2,
        RCAR_ISP_PORT3,
        RCAR_ISP_PORT4,
        RCAR_ISP_PORT5,
        RCAR_ISP_PORT6,
        RCAR_ISP_PORT7,
        RCAR_ISP_NUM_PADS,
};

struct rcar_isp {
        struct device *dev;
        void __iomem *csbase;
        struct reset_control *rstc;

        enum rcar_isp_input csi_input;

        struct v4l2_subdev subdev;
        struct media_pad pads[RCAR_ISP_NUM_PADS];

        struct v4l2_async_notifier notifier;
        struct v4l2_subdev *remote;
        unsigned int remote_pad;

        int stream_count;
};

static inline struct rcar_isp *sd_to_isp(struct v4l2_subdev *sd)
{
        return container_of(sd, struct rcar_isp, subdev);
}

static inline struct rcar_isp *notifier_to_isp(struct v4l2_async_notifier *n)
{
        return container_of(n, struct rcar_isp, notifier);
}

static void risp_write_cs(struct rcar_isp *isp, u32 offset, u32 value)
{
        iowrite32(value, isp->csbase + offset);
}

static u32 risp_read_cs(struct rcar_isp *isp, u32 offset)
{
        return ioread32(isp->csbase + offset);
}

static int risp_power_on(struct rcar_isp *isp)
{
        int ret;

        ret = pm_runtime_resume_and_get(isp->dev);
        if (ret < 0)
                return ret;

        ret = reset_control_deassert(isp->rstc);
        if (ret < 0) {
                pm_runtime_put(isp->dev);
                return ret;
        }

        return 0;
}

static void risp_power_off(struct rcar_isp *isp)
{
        reset_control_assert(isp->rstc);
        pm_runtime_put(isp->dev);
}

static int risp_start(struct rcar_isp *isp, struct v4l2_subdev_state *state)
{
        const struct v4l2_mbus_framefmt *fmt;
        const struct rcar_isp_format *format;
        unsigned int vc;
        u32 sel_csi = 0;
        int ret;

        fmt = v4l2_subdev_state_get_format(state, RCAR_ISP_SINK);
        if (!fmt)
                return -EINVAL;

        format = risp_code_to_fmt(fmt->code);
        if (!format) {
                dev_err(isp->dev, "Unsupported bus format\n");
                return -EINVAL;
        }

        ret = risp_power_on(isp);
        if (ret) {
                dev_err(isp->dev, "Failed to power on ISP\n");
                return ret;
        }

        /* Select CSI-2 input source. */
        if (isp->csi_input == RISP_CSI_INPUT1)
                sel_csi = ISPINPUTSEL0_SEL_CSI0;

        risp_write_cs(isp, ISPINPUTSEL0_REG,
                      risp_read_cs(isp, ISPINPUTSEL0_REG) | sel_csi);

        /* Configure Channel Selector. */
        for (vc = 0; vc < 4; vc++) {
                u8 ch = vc + 4;
                u8 dt = format->datatype;

                risp_write_cs(isp, ISPCS_FILTER_ID_CH_REG(ch), BIT(vc));
                risp_write_cs(isp, ISPCS_DT_CODE03_CH_REG(ch),
                              ISPCS_DT_CODE03_EN3 | ISPCS_DT_CODE03_DT3(dt) |
                              ISPCS_DT_CODE03_EN2 | ISPCS_DT_CODE03_DT2(dt) |
                              ISPCS_DT_CODE03_EN1 | ISPCS_DT_CODE03_DT1(dt) |
                              ISPCS_DT_CODE03_EN0 | ISPCS_DT_CODE03_DT0(dt));
        }

        /* Setup processing method. */
        risp_write_cs(isp, ISPPROCMODE_DT_REG(format->datatype),
                      ISPPROCMODE_DT_PROC_MODE_VC3(format->procmode) |
                      ISPPROCMODE_DT_PROC_MODE_VC2(format->procmode) |
                      ISPPROCMODE_DT_PROC_MODE_VC1(format->procmode) |
                      ISPPROCMODE_DT_PROC_MODE_VC0(format->procmode));

        /* Start ISP. */
        risp_write_cs(isp, ISPSTART_REG, ISPSTART_START);

        ret = v4l2_subdev_enable_streams(isp->remote, isp->remote_pad,
                                         BIT_ULL(0));
        if (ret)
                risp_power_off(isp);

        return ret;
}

static void risp_stop(struct rcar_isp *isp)
{
        v4l2_subdev_disable_streams(isp->remote, isp->remote_pad, BIT_ULL(0));

        /* Stop ISP. */
        risp_write_cs(isp, ISPSTART_REG, ISPSTART_STOP);

        risp_power_off(isp);
}

static int risp_enable_streams(struct v4l2_subdev *sd,
                               struct v4l2_subdev_state *state, u32 source_pad,
                               u64 source_streams_mask)
{
        struct rcar_isp *isp = sd_to_isp(sd);
        int ret = 0;

        if (source_streams_mask != 1)
                return -EINVAL;

        if (!isp->remote)
                return -ENODEV;

        if (isp->stream_count == 0) {
                ret = risp_start(isp, state);
                if (ret)
                        return ret;
        }

        isp->stream_count += 1;

        return ret;
}

static int risp_disable_streams(struct v4l2_subdev *sd,
                                struct v4l2_subdev_state *state, u32 source_pad,
                                u64 source_streams_mask)
{
        struct rcar_isp *isp = sd_to_isp(sd);

        if (source_streams_mask != 1)
                return -EINVAL;

        if (!isp->remote)
                return -ENODEV;

        if (isp->stream_count == 1)
                risp_stop(isp);

        isp->stream_count -= 1;

        return 0;
}

static int risp_set_pad_format(struct v4l2_subdev *sd,
                               struct v4l2_subdev_state *state,
                               struct v4l2_subdev_format *format)
{
        struct v4l2_mbus_framefmt *framefmt;

        if (format->pad > RCAR_ISP_SINK)
                return v4l2_subdev_get_fmt(sd, state, format);

        if (!risp_code_to_fmt(format->format.code))
                format->format.code = rcar_isp_formats[0].code;

        for (unsigned int i = 0; i < RCAR_ISP_NUM_PADS; i++) {
                framefmt = v4l2_subdev_state_get_format(state, i);
                *framefmt = format->format;
        }

        return 0;
}

static const struct v4l2_subdev_pad_ops risp_pad_ops = {
        .enable_streams = risp_enable_streams,
        .disable_streams = risp_disable_streams,
        .set_fmt = risp_set_pad_format,
        .get_fmt = v4l2_subdev_get_fmt,
        .link_validate = v4l2_subdev_link_validate_default,
};

static const struct v4l2_subdev_ops rcar_isp_subdev_ops = {
        .pad    = &risp_pad_ops,
};

/* -----------------------------------------------------------------------------
 * Async handling and registration of subdevices and links
 */

static int risp_notify_bound(struct v4l2_async_notifier *notifier,
                             struct v4l2_subdev *subdev,
                             struct v4l2_async_connection *asd)
{
        struct rcar_isp *isp = notifier_to_isp(notifier);
        int pad;

        pad = media_entity_get_fwnode_pad(&subdev->entity, asd->match.fwnode,
                                          MEDIA_PAD_FL_SOURCE);
        if (pad < 0) {
                dev_err(isp->dev, "Failed to find pad for %s\n", subdev->name);
                return pad;
        }

        isp->remote = subdev;
        isp->remote_pad = pad;

        dev_dbg(isp->dev, "Bound %s pad: %d\n", subdev->name, pad);

        return media_create_pad_link(&subdev->entity, pad,
                                     &isp->subdev.entity, 0,
                                     MEDIA_LNK_FL_ENABLED |
                                     MEDIA_LNK_FL_IMMUTABLE);
}

static void risp_notify_unbind(struct v4l2_async_notifier *notifier,
                               struct v4l2_subdev *subdev,
                               struct v4l2_async_connection *asd)
{
        struct rcar_isp *isp = notifier_to_isp(notifier);

        isp->remote = NULL;

        dev_dbg(isp->dev, "Unbind %s\n", subdev->name);
}

static const struct v4l2_async_notifier_operations risp_notify_ops = {
        .bound = risp_notify_bound,
        .unbind = risp_notify_unbind,
};

static int risp_parse_dt(struct rcar_isp *isp)
{
        struct v4l2_async_connection *asd;
        struct fwnode_handle *fwnode;
        struct fwnode_handle *ep;
        unsigned int id;
        int ret;

        for (id = 0; id < 2; id++) {
                ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(isp->dev),
                                                     0, id, 0);
                if (ep)
                        break;
        }

        if (!ep) {
                dev_err(isp->dev, "Not connected to subdevice\n");
                return -EINVAL;
        }

        if (id == 1)
                isp->csi_input = RISP_CSI_INPUT1;

        fwnode = fwnode_graph_get_remote_endpoint(ep);
        fwnode_handle_put(ep);

        dev_dbg(isp->dev, "Found '%pOF'\n", to_of_node(fwnode));

        v4l2_async_subdev_nf_init(&isp->notifier, &isp->subdev);
        isp->notifier.ops = &risp_notify_ops;

        asd = v4l2_async_nf_add_fwnode(&isp->notifier, fwnode,
                                       struct v4l2_async_connection);
        fwnode_handle_put(fwnode);
        if (IS_ERR(asd))
                return PTR_ERR(asd);

        ret = v4l2_async_nf_register(&isp->notifier);
        if (ret)
                v4l2_async_nf_cleanup(&isp->notifier);

        return ret;
}

/* -----------------------------------------------------------------------------
 * Platform Device Driver
 */

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

static int risp_probe_resources(struct rcar_isp *isp,
                                struct platform_device *pdev)
{
        struct resource *res;

        /*
         * For backward compatibility allow cs base to be the only reg if no
         * reg-names are set in DT.
         */
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cs");
        if (!res)
                isp->csbase = devm_platform_ioremap_resource(pdev, 0);
        else
                isp->csbase = devm_ioremap_resource(&pdev->dev, res);

        if (IS_ERR(isp->csbase))
                return PTR_ERR(isp->csbase);

        isp->rstc = devm_reset_control_get(&pdev->dev, NULL);

        return PTR_ERR_OR_ZERO(isp->rstc);
}

static const struct of_device_id risp_of_id_table[] = {
        { .compatible = "renesas,r8a779a0-isp" },
        { .compatible = "renesas,r8a779g0-isp" },
        /* Keep above for compatibility with old DTB files. */
        { .compatible = "renesas,rcar-gen4-isp" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, risp_of_id_table);

static int risp_probe(struct platform_device *pdev)
{
        struct rcar_isp *isp;
        unsigned int i;
        int ret;

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

        isp->dev = &pdev->dev;

        ret = risp_probe_resources(isp, pdev);
        if (ret) {
                dev_err(isp->dev, "Failed to get resources\n");
                return ret;
        }

        platform_set_drvdata(pdev, isp);

        pm_runtime_enable(&pdev->dev);

        ret = risp_parse_dt(isp);
        if (ret)
                goto error_pm;

        isp->subdev.owner = THIS_MODULE;
        isp->subdev.dev = &pdev->dev;
        v4l2_subdev_init(&isp->subdev, &rcar_isp_subdev_ops);
        v4l2_set_subdevdata(&isp->subdev, &pdev->dev);
        snprintf(isp->subdev.name, sizeof(isp->subdev.name), "%s %s",
                 KBUILD_MODNAME, dev_name(&pdev->dev));
        isp->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;

        isp->subdev.entity.function = MEDIA_ENT_F_VID_MUX;
        isp->subdev.entity.ops = &risp_entity_ops;

        isp->pads[RCAR_ISP_SINK].flags = MEDIA_PAD_FL_SINK;
        for (i = RCAR_ISP_PORT0; i < RCAR_ISP_NUM_PADS; i++)
                isp->pads[i].flags = MEDIA_PAD_FL_SOURCE;

        ret = media_entity_pads_init(&isp->subdev.entity, RCAR_ISP_NUM_PADS,
                                     isp->pads);
        if (ret)
                goto error_notifier;

        ret = v4l2_subdev_init_finalize(&isp->subdev);
        if (ret)
                goto error_notifier;

        ret = v4l2_async_register_subdev(&isp->subdev);
        if (ret < 0)
                goto error_subdev;

        dev_info(isp->dev, "Using CSI-2 input: %u\n", isp->csi_input);

        return 0;

error_subdev:
        v4l2_subdev_cleanup(&isp->subdev);
error_notifier:
        v4l2_async_nf_unregister(&isp->notifier);
        v4l2_async_nf_cleanup(&isp->notifier);
error_pm:
        pm_runtime_disable(&pdev->dev);

        return ret;
}

static void risp_remove(struct platform_device *pdev)
{
        struct rcar_isp *isp = platform_get_drvdata(pdev);

        v4l2_async_nf_unregister(&isp->notifier);
        v4l2_async_nf_cleanup(&isp->notifier);

        v4l2_async_unregister_subdev(&isp->subdev);
        v4l2_subdev_cleanup(&isp->subdev);

        pm_runtime_disable(&pdev->dev);
}

static struct platform_driver rcar_isp_driver = {
        .driver = {
                .name = "rcar-isp",
                .suppress_bind_attrs = true,
                .of_match_table = risp_of_id_table,
        },
        .probe = risp_probe,
        .remove = risp_remove,
};

module_platform_driver(rcar_isp_driver);

MODULE_AUTHOR("Niklas Söderlund <niklas.soderlund@ragnatech.se>");
MODULE_DESCRIPTION("Renesas R-Car ISP Channel Selector driver");
MODULE_LICENSE("GPL");