// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2016 Texas Instruments
 * Author: Jyri Sarha <jsarha@ti.com>
 */

#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

#define HOTPLUG_DEBOUNCE_MS             1100

struct tfp410 {
        struct drm_bridge       bridge;
        struct drm_connector    connector;

        u32                     bus_format;
        struct delayed_work     hpd_work;
        struct gpio_desc        *powerdown;

        struct drm_bridge_timings timings;

        struct device *dev;
};

static inline struct tfp410 *
drm_bridge_to_tfp410(struct drm_bridge *bridge)
{
        return container_of(bridge, struct tfp410, bridge);
}

static inline struct tfp410 *
drm_connector_to_tfp410(struct drm_connector *connector)
{
        return container_of(connector, struct tfp410, connector);
}

static int tfp410_get_modes(struct drm_connector *connector)
{
        struct tfp410 *dvi = drm_connector_to_tfp410(connector);
        const struct drm_edid *drm_edid;
        int ret;

        if (dvi->bridge.next_bridge->ops & DRM_BRIDGE_OP_EDID) {
                drm_edid = drm_bridge_edid_read(dvi->bridge.next_bridge, connector);
                if (!drm_edid)
                        DRM_INFO("EDID read failed. Fallback to standard modes\n");
        } else {
                drm_edid = NULL;
        }

        drm_edid_connector_update(connector, drm_edid);

        if (!drm_edid) {
                /*
                 * No EDID, fallback on the XGA standard modes and prefer a mode
                 * pretty much anything can handle.
                 */
                ret = drm_add_modes_noedid(connector, 1920, 1200);
                drm_set_preferred_mode(connector, 1024, 768);
                return ret;
        }

        ret = drm_edid_connector_add_modes(connector);

        drm_edid_free(drm_edid);

        return ret;
}

static const struct drm_connector_helper_funcs tfp410_con_helper_funcs = {
        .get_modes      = tfp410_get_modes,
};

static enum drm_connector_status
tfp410_connector_detect(struct drm_connector *connector, bool force)
{
        struct tfp410 *dvi = drm_connector_to_tfp410(connector);

        return drm_bridge_detect(dvi->bridge.next_bridge, connector);
}

static const struct drm_connector_funcs tfp410_con_funcs = {
        .detect                 = tfp410_connector_detect,
        .fill_modes             = drm_helper_probe_single_connector_modes,
        .destroy                = drm_connector_cleanup,
        .reset                  = drm_atomic_helper_connector_reset,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
};

static void tfp410_hpd_work_func(struct work_struct *work)
{
        struct tfp410 *dvi;

        dvi = container_of(work, struct tfp410, hpd_work.work);

        if (dvi->bridge.dev)
                drm_helper_hpd_irq_event(dvi->bridge.dev);
}

static void tfp410_hpd_callback(void *arg, enum drm_connector_status status)
{
        struct tfp410 *dvi = arg;

        mod_delayed_work(system_wq, &dvi->hpd_work,
                         msecs_to_jiffies(HOTPLUG_DEBOUNCE_MS));
}

static int tfp410_attach(struct drm_bridge *bridge,
                         struct drm_encoder *encoder,
                         enum drm_bridge_attach_flags flags)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);
        int ret;

        ret = drm_bridge_attach(encoder, dvi->bridge.next_bridge, bridge,
                                DRM_BRIDGE_ATTACH_NO_CONNECTOR);
        if (ret < 0)
                return ret;

        if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
                return 0;

        if (dvi->bridge.next_bridge->ops & DRM_BRIDGE_OP_DETECT)
                dvi->connector.polled = DRM_CONNECTOR_POLL_HPD;
        else
                dvi->connector.polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;

        if (dvi->bridge.next_bridge->ops & DRM_BRIDGE_OP_HPD) {
                INIT_DELAYED_WORK(&dvi->hpd_work, tfp410_hpd_work_func);
                drm_bridge_hpd_enable(dvi->bridge.next_bridge, tfp410_hpd_callback,
                                      dvi);
        }

        drm_connector_helper_add(&dvi->connector,
                                 &tfp410_con_helper_funcs);
        ret = drm_connector_init_with_ddc(bridge->dev, &dvi->connector,
                                          &tfp410_con_funcs,
                                          dvi->bridge.next_bridge->type,
                                          dvi->bridge.next_bridge->ddc);
        if (ret) {
                dev_err(dvi->dev, "drm_connector_init_with_ddc() failed: %d\n",
                        ret);
                return ret;
        }

        drm_display_info_set_bus_formats(&dvi->connector.display_info,
                                         &dvi->bus_format, 1);

        drm_connector_attach_encoder(&dvi->connector, encoder);

        return 0;
}

static void tfp410_detach(struct drm_bridge *bridge)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);

        if (dvi->connector.dev && dvi->bridge.next_bridge->ops & DRM_BRIDGE_OP_HPD) {
                drm_bridge_hpd_disable(dvi->bridge.next_bridge);
                cancel_delayed_work_sync(&dvi->hpd_work);
        }
}

static void tfp410_enable(struct drm_bridge *bridge)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);

        gpiod_set_value_cansleep(dvi->powerdown, 0);
}

static void tfp410_disable(struct drm_bridge *bridge)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);

        gpiod_set_value_cansleep(dvi->powerdown, 1);
}

static enum drm_mode_status tfp410_mode_valid(struct drm_bridge *bridge,
                                              const struct drm_display_info *info,
                                              const struct drm_display_mode *mode)
{
        if (mode->clock < 25000)
                return MODE_CLOCK_LOW;

        if (mode->clock > 165000)
                return MODE_CLOCK_HIGH;

        return MODE_OK;
}

static u32 *tfp410_get_input_bus_fmts(struct drm_bridge *bridge,
                                      struct drm_bridge_state *bridge_state,
                                      struct drm_crtc_state *crtc_state,
                                      struct drm_connector_state *conn_state,
                                      u32 output_fmt,
                                      unsigned int *num_input_fmts)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);
        u32 *input_fmts;

        *num_input_fmts = 0;

        input_fmts = kzalloc_obj(*input_fmts);
        if (!input_fmts)
                return NULL;

        *num_input_fmts = 1;
        input_fmts[0] = dvi->bus_format;

        return input_fmts;
}

static int tfp410_atomic_check(struct drm_bridge *bridge,
                               struct drm_bridge_state *bridge_state,
                               struct drm_crtc_state *crtc_state,
                               struct drm_connector_state *conn_state)
{
        struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);

        /*
         * There might be flags negotiation supported in future.
         * Set the bus flags in atomic_check statically for now.
         */
        bridge_state->input_bus_cfg.flags = dvi->timings.input_bus_flags;

        return 0;
}

static const struct drm_bridge_funcs tfp410_bridge_funcs = {
        .attach         = tfp410_attach,
        .detach         = tfp410_detach,
        .enable         = tfp410_enable,
        .disable        = tfp410_disable,
        .mode_valid     = tfp410_mode_valid,
        .atomic_reset = drm_atomic_helper_bridge_reset,
        .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
        .atomic_get_input_bus_fmts = tfp410_get_input_bus_fmts,
        .atomic_check = tfp410_atomic_check,
};

static const struct drm_bridge_timings tfp410_default_timings = {
        .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
                         | DRM_BUS_FLAG_DE_HIGH,
        .setup_time_ps = 1200,
        .hold_time_ps = 1300,
};

static int tfp410_parse_timings(struct tfp410 *dvi, bool i2c)
{
        struct drm_bridge_timings *timings = &dvi->timings;
        struct device_node *ep;
        u32 pclk_sample = 0;
        u32 bus_width = 24;
        u32 deskew = 0;

        /* Start with defaults. */
        *timings = tfp410_default_timings;

        if (i2c)
                /*
                 * In I2C mode timings are configured through the I2C interface.
                 * As the driver doesn't support I2C configuration yet, we just
                 * go with the defaults (BSEL=1, DSEL=1, DKEN=0, EDGE=1).
                 */
                return 0;

        /*
         * In non-I2C mode, timings are configured through the BSEL, DSEL, DKEN
         * and EDGE pins. They are specified in DT through endpoint properties
         * and vendor-specific properties.
         */
        ep = of_graph_get_endpoint_by_regs(dvi->dev->of_node, 0, 0);
        if (!ep)
                return -EINVAL;

        /* Get the sampling edge from the endpoint. */
        of_property_read_u32(ep, "pclk-sample", &pclk_sample);
        of_property_read_u32(ep, "bus-width", &bus_width);
        of_node_put(ep);

        timings->input_bus_flags = DRM_BUS_FLAG_DE_HIGH;

        switch (pclk_sample) {
        case 0:
                timings->input_bus_flags |= DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE
                                         |  DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE;
                break;
        case 1:
                timings->input_bus_flags |= DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
                                         |  DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE;
                break;
        default:
                return -EINVAL;
        }

        switch (bus_width) {
        case 12:
                dvi->bus_format = MEDIA_BUS_FMT_RGB888_2X12_LE;
                break;
        case 24:
                dvi->bus_format = MEDIA_BUS_FMT_RGB888_1X24;
                break;
        default:
                return -EINVAL;
        }

        /* Get the setup and hold time from vendor-specific properties. */
        of_property_read_u32(dvi->dev->of_node, "ti,deskew", &deskew);
        if (deskew > 7)
                return -EINVAL;

        timings->setup_time_ps = 1200 - 350 * ((s32)deskew - 4);
        timings->hold_time_ps = max(0, 1300 + 350 * ((s32)deskew - 4));

        return 0;
}

static int tfp410_init(struct device *dev, bool i2c)
{
        struct device_node *node;
        struct tfp410 *dvi;
        int ret;

        if (!dev->of_node) {
                dev_err(dev, "device-tree data is missing\n");
                return -ENXIO;
        }

        dvi = devm_drm_bridge_alloc(dev, struct tfp410, bridge,
                                    &tfp410_bridge_funcs);
        if (IS_ERR(dvi))
                return PTR_ERR(dvi);

        dvi->dev = dev;
        dev_set_drvdata(dev, dvi);

        dvi->bridge.of_node = dev->of_node;
        dvi->bridge.timings = &dvi->timings;
        dvi->bridge.type = DRM_MODE_CONNECTOR_DVID;

        ret = tfp410_parse_timings(dvi, i2c);
        if (ret)
                return ret;

        /* Get the next bridge, connected to port@1. */
        node = of_graph_get_remote_node(dev->of_node, 1, -1);
        if (!node)
                return -ENODEV;

        dvi->bridge.next_bridge = of_drm_find_and_get_bridge(node);
        of_node_put(node);

        if (!dvi->bridge.next_bridge)
                return -EPROBE_DEFER;

        /* Get the powerdown GPIO. */
        dvi->powerdown = devm_gpiod_get_optional(dev, "powerdown",
                                                 GPIOD_OUT_HIGH);
        if (IS_ERR(dvi->powerdown)) {
                dev_err(dev, "failed to parse powerdown gpio\n");
                return PTR_ERR(dvi->powerdown);
        }

        /*  Register the DRM bridge. */
        drm_bridge_add(&dvi->bridge);

        return 0;
}

static void tfp410_fini(struct device *dev)
{
        struct tfp410 *dvi = dev_get_drvdata(dev);

        drm_bridge_remove(&dvi->bridge);
}

static int tfp410_probe(struct platform_device *pdev)
{
        return tfp410_init(&pdev->dev, false);
}

static void tfp410_remove(struct platform_device *pdev)
{
        tfp410_fini(&pdev->dev);
}

static const struct of_device_id tfp410_match[] = {
        { .compatible = "ti,tfp410" },
        {},
};
MODULE_DEVICE_TABLE(of, tfp410_match);

static struct platform_driver tfp410_platform_driver = {
        .probe  = tfp410_probe,
        .remove = tfp410_remove,
        .driver = {
                .name           = "tfp410-bridge",
                .of_match_table = tfp410_match,
        },
};

#if IS_ENABLED(CONFIG_I2C)
/* There is currently no i2c functionality. */
static int tfp410_i2c_probe(struct i2c_client *client)
{
        int reg;

        if (!client->dev.of_node ||
            of_property_read_u32(client->dev.of_node, "reg", &reg)) {
                dev_err(&client->dev,
                        "Can't get i2c reg property from device-tree\n");
                return -ENXIO;
        }

        return tfp410_init(&client->dev, true);
}

static void tfp410_i2c_remove(struct i2c_client *client)
{
        tfp410_fini(&client->dev);
}

static const struct i2c_device_id tfp410_i2c_ids[] = {
        { "tfp410" },
        { }
};
MODULE_DEVICE_TABLE(i2c, tfp410_i2c_ids);

static struct i2c_driver tfp410_i2c_driver = {
        .driver = {
                .name   = "tfp410",
                .of_match_table = tfp410_match,
        },
        .id_table       = tfp410_i2c_ids,
        .probe          = tfp410_i2c_probe,
        .remove         = tfp410_i2c_remove,
};
#endif /* IS_ENABLED(CONFIG_I2C) */

static struct {
        uint i2c:1;
        uint platform:1;
}  tfp410_registered_driver;

static int __init tfp410_module_init(void)
{
        int ret;

#if IS_ENABLED(CONFIG_I2C)
        ret = i2c_add_driver(&tfp410_i2c_driver);
        if (ret)
                pr_err("%s: registering i2c driver failed: %d",
                       __func__, ret);
        else
                tfp410_registered_driver.i2c = 1;
#endif

        ret = platform_driver_register(&tfp410_platform_driver);
        if (ret)
                pr_err("%s: registering platform driver failed: %d",
                       __func__, ret);
        else
                tfp410_registered_driver.platform = 1;

        if (tfp410_registered_driver.i2c ||
            tfp410_registered_driver.platform)
                return 0;

        return ret;
}
module_init(tfp410_module_init);

static void __exit tfp410_module_exit(void)
{
#if IS_ENABLED(CONFIG_I2C)
        if (tfp410_registered_driver.i2c)
                i2c_del_driver(&tfp410_i2c_driver);
#endif
        if (tfp410_registered_driver.platform)
                platform_driver_unregister(&tfp410_platform_driver);
}
module_exit(tfp410_module_exit);

MODULE_AUTHOR("Jyri Sarha <jsarha@ti.com>");
MODULE_DESCRIPTION("TI TFP410 DVI bridge driver");
MODULE_LICENSE("GPL");