// SPDX-License-Identifier: GPL-2.0-only
/*
 * NXP PTN3460 DP/LVDS bridge driver
 *
 * Copyright (C) 2013 Google, Inc.
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.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_of.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

#define PTN3460_EDID_ADDR                       0x0
#define PTN3460_EDID_EMULATION_ADDR             0x84
#define PTN3460_EDID_ENABLE_EMULATION           0
#define PTN3460_EDID_EMULATION_SELECTION        1
#define PTN3460_EDID_SRAM_LOAD_ADDR             0x85

struct ptn3460_bridge {
        struct drm_connector connector;
        struct i2c_client *client;
        struct drm_bridge bridge;
        struct drm_bridge *panel_bridge;
        struct gpio_desc *gpio_pd_n;
        struct gpio_desc *gpio_rst_n;
        u32 edid_emulation;
        bool enabled;
};

static inline struct ptn3460_bridge *
                bridge_to_ptn3460(struct drm_bridge *bridge)
{
        return container_of(bridge, struct ptn3460_bridge, bridge);
}

static inline struct ptn3460_bridge *
                connector_to_ptn3460(struct drm_connector *connector)
{
        return container_of(connector, struct ptn3460_bridge, connector);
}

static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
                u8 *buf, int len)
{
        int ret;

        ret = i2c_master_send(ptn_bridge->client, &addr, 1);
        if (ret < 0) {
                DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
                return ret;
        }

        ret = i2c_master_recv(ptn_bridge->client, buf, len);
        if (ret < 0) {
                DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
                return ret;
        }

        return 0;
}

static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
                char val)
{
        int ret;
        char buf[2];

        buf[0] = addr;
        buf[1] = val;

        ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
        if (ret < 0) {
                DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
                return ret;
        }

        return 0;
}

static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
{
        int ret;
        char val;

        /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
        ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
                        ptn_bridge->edid_emulation);
        if (ret) {
                DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
                return ret;
        }

        /* Enable EDID emulation and select the desired EDID */
        val = 1 << PTN3460_EDID_ENABLE_EMULATION |
                ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;

        ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
        if (ret) {
                DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
                return ret;
        }

        return 0;
}

static void ptn3460_pre_enable(struct drm_bridge *bridge)
{
        struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
        int ret;

        if (ptn_bridge->enabled)
                return;

        gpiod_set_value(ptn_bridge->gpio_pd_n, 1);

        gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
        usleep_range(10, 20);
        gpiod_set_value(ptn_bridge->gpio_rst_n, 1);

        /*
         * There's a bug in the PTN chip where it falsely asserts hotplug before
         * it is fully functional. We're forced to wait for the maximum start up
         * time specified in the chip's datasheet to make sure we're really up.
         */
        msleep(90);

        ret = ptn3460_select_edid(ptn_bridge);
        if (ret)
                DRM_ERROR("Select EDID failed ret=%d\n", ret);

        ptn_bridge->enabled = true;
}

static void ptn3460_disable(struct drm_bridge *bridge)
{
        struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);

        if (!ptn_bridge->enabled)
                return;

        ptn_bridge->enabled = false;

        gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
        gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
}


static const struct drm_edid *ptn3460_edid_read(struct drm_bridge *bridge,
                                                struct drm_connector *connector)
{
        struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
        const struct drm_edid *drm_edid = NULL;
        bool power_off;
        u8 *edid;
        int ret;

        power_off = !ptn_bridge->enabled;
        ptn3460_pre_enable(&ptn_bridge->bridge);

        edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
        if (!edid) {
                DRM_ERROR("Failed to allocate EDID\n");
                goto out;
        }

        ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
                                 EDID_LENGTH);
        if (ret) {
                kfree(edid);
                goto out;
        }

        drm_edid = drm_edid_alloc(edid, EDID_LENGTH);

out:
        if (power_off)
                ptn3460_disable(&ptn_bridge->bridge);

        return drm_edid;
}

static int ptn3460_connector_get_modes(struct drm_connector *connector)
{
        struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
        const struct drm_edid *drm_edid;
        int num_modes;

        drm_edid = ptn3460_edid_read(&ptn_bridge->bridge, connector);
        drm_edid_connector_update(connector, drm_edid);
        num_modes = drm_edid_connector_add_modes(connector);
        drm_edid_free(drm_edid);

        return num_modes;
}

static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
        .get_modes = ptn3460_connector_get_modes,
};

static const struct drm_connector_funcs ptn3460_connector_funcs = {
        .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 int ptn3460_bridge_attach(struct drm_bridge *bridge,
                                 struct drm_encoder *encoder,
                                 enum drm_bridge_attach_flags flags)
{
        struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
        int ret;

        /* Let this driver create connector if requested */
        ret = drm_bridge_attach(encoder, ptn_bridge->panel_bridge,
                                bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
        if (ret < 0)
                return ret;

        if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
                return 0;

        ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
        ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
                        &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
        if (ret) {
                DRM_ERROR("Failed to initialize connector with drm\n");
                return ret;
        }
        drm_connector_helper_add(&ptn_bridge->connector,
                                        &ptn3460_connector_helper_funcs);
        drm_connector_register(&ptn_bridge->connector);
        drm_connector_attach_encoder(&ptn_bridge->connector,
                                                        encoder);

        drm_helper_hpd_irq_event(ptn_bridge->connector.dev);

        return ret;
}

static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
        .pre_enable = ptn3460_pre_enable,
        .disable = ptn3460_disable,
        .attach = ptn3460_bridge_attach,
        .edid_read = ptn3460_edid_read,
};

static int ptn3460_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct ptn3460_bridge *ptn_bridge;
        struct drm_bridge *panel_bridge;
        int ret;

        ptn_bridge = devm_drm_bridge_alloc(dev, struct ptn3460_bridge, bridge,
                                           &ptn3460_bridge_funcs);
        if (IS_ERR(ptn_bridge))
                return PTR_ERR(ptn_bridge);

        panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
        if (IS_ERR(panel_bridge))
                return PTR_ERR(panel_bridge);

        ptn_bridge->panel_bridge = panel_bridge;
        ptn_bridge->client = client;

        ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
                                               GPIOD_OUT_HIGH);
        if (IS_ERR(ptn_bridge->gpio_pd_n)) {
                ret = PTR_ERR(ptn_bridge->gpio_pd_n);
                dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
                return ret;
        }

        /*
         * Request the reset pin low to avoid the bridge being
         * initialized prematurely
         */
        ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
                                                GPIOD_OUT_LOW);
        if (IS_ERR(ptn_bridge->gpio_rst_n)) {
                ret = PTR_ERR(ptn_bridge->gpio_rst_n);
                DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
                return ret;
        }

        ret = of_property_read_u32(dev->of_node, "edid-emulation",
                        &ptn_bridge->edid_emulation);
        if (ret) {
                dev_err(dev, "Can't read EDID emulation value\n");
                return ret;
        }

        ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
        ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
        ptn_bridge->bridge.of_node = dev->of_node;
        drm_bridge_add(&ptn_bridge->bridge);

        i2c_set_clientdata(client, ptn_bridge);

        return 0;
}

static void ptn3460_remove(struct i2c_client *client)
{
        struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);

        drm_bridge_remove(&ptn_bridge->bridge);
}

static const struct i2c_device_id ptn3460_i2c_table[] = {
        { "ptn3460" },
        {}
};
MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);

static const struct of_device_id ptn3460_match[] = {
        { .compatible = "nxp,ptn3460" },
        {},
};
MODULE_DEVICE_TABLE(of, ptn3460_match);

static struct i2c_driver ptn3460_driver = {
        .id_table       = ptn3460_i2c_table,
        .probe          = ptn3460_probe,
        .remove         = ptn3460_remove,
        .driver         = {
                .name   = "nxp,ptn3460",
                .of_match_table = ptn3460_match,
        },
};
module_i2c_driver(ptn3460_driver);

MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
MODULE_LICENSE("GPL v2");