/*
 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
 * Parts of this file were based on sources as follows:
 *
 * Copyright (C) 2006-2008 Intel Corporation
 * Copyright (C) 2007 Amos Lee <amos_lee@storlinksemi.com>
 * Copyright (C) 2007 Dave Airlie <airlied@linux.ie>
 * Copyright (C) 2011 Texas Instruments
 * Copyright (C) 2017 Eric Anholt
 *
 * This program is free software and is provided to you under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation, and any use by you of this program is subject to the terms of
 * such GNU licence.
 */

/**
 * DOC: Faraday TV Encoder TVE200 DRM Driver
 *
 * The Faraday TV Encoder TVE200 is also known as the Gemini TV Interface
 * Controller (TVC) and is found in the Gemini Chipset from Storlink
 * Semiconductor (later Storm Semiconductor, later Cortina Systems)
 * but also in the Grain Media GM8180 chipset. On the Gemini the module
 * is connected to 8 data lines and a single clock line, comprising an
 * 8-bit BT.656 interface.
 *
 * This is a very basic YUV display driver. The datasheet specifies that
 * it supports the ITU BT.656 standard. It requires a 27 MHz clock which is
 * the hallmark of any TV encoder supporting both PAL and NTSC.
 *
 * This driver exposes a standard KMS interface for this TV encoder.
 */

#include <linux/clk.h>
#include <linux/dma-buf.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/version.h>

#include <drm/drmP.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_panel.h>
#include <drm/drm_of.h>
#include <drm/drm_bridge.h>

#include "tve200_drm.h"

#define DRIVER_DESC      "DRM module for Faraday TVE200"

static const struct drm_mode_config_funcs mode_config_funcs = {
        .fb_create = drm_gem_fb_create,
        .atomic_check = drm_atomic_helper_check,
        .atomic_commit = drm_atomic_helper_commit,
};

static int tve200_modeset_init(struct drm_device *dev)
{
        struct drm_mode_config *mode_config;
        struct tve200_drm_dev_private *priv = dev->dev_private;
        struct drm_panel *panel;
        struct drm_bridge *bridge;
        int ret = 0;

        drm_mode_config_init(dev);
        mode_config = &dev->mode_config;
        mode_config->funcs = &mode_config_funcs;
        mode_config->min_width = 352;
        mode_config->max_width = 720;
        mode_config->min_height = 240;
        mode_config->max_height = 576;

        ret = drm_of_find_panel_or_bridge(dev->dev->of_node,
                                          0, 0, &panel, &bridge);
        if (ret && ret != -ENODEV)
                return ret;
        if (panel) {
                bridge = drm_panel_bridge_add(panel,
                                              DRM_MODE_CONNECTOR_Unknown);
                if (IS_ERR(bridge)) {
                        ret = PTR_ERR(bridge);
                        goto out_bridge;
                }
        } else {
                /*
                 * TODO: when we are using a different bridge than a panel
                 * (such as a dumb VGA connector) we need to devise a different
                 * method to get the connector out of the bridge.
                 */
                dev_err(dev->dev, "the bridge is not a panel\n");
                goto out_bridge;
        }

        ret = tve200_display_init(dev);
        if (ret) {
                dev_err(dev->dev, "failed to init display\n");
                goto out_bridge;
        }

        ret = drm_simple_display_pipe_attach_bridge(&priv->pipe,
                                                    bridge);
        if (ret) {
                dev_err(dev->dev, "failed to attach bridge\n");
                goto out_bridge;
        }

        priv->panel = panel;
        priv->connector = panel->connector;
        priv->bridge = bridge;

        dev_info(dev->dev, "attached to panel %s\n",
                 dev_name(panel->dev));

        ret = drm_vblank_init(dev, 1);
        if (ret) {
                dev_err(dev->dev, "failed to init vblank\n");
                goto out_bridge;
        }

        drm_mode_config_reset(dev);

        /*
         * Passing in 16 here will make the RGB656 mode the default
         * Passing in 32 will use XRGB8888 mode
         */
        drm_fb_cma_fbdev_init(dev, 16, 0);
        drm_kms_helper_poll_init(dev);

        goto finish;

out_bridge:
        if (panel)
                drm_panel_bridge_remove(bridge);
        drm_mode_config_cleanup(dev);
finish:
        return ret;
}

DEFINE_DRM_GEM_CMA_FOPS(drm_fops);

static struct drm_driver tve200_drm_driver = {
        .driver_features =
                DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
        .lastclose = drm_fb_helper_lastclose,
        .ioctls = NULL,
        .fops = &drm_fops,
        .name = "tve200",
        .desc = DRIVER_DESC,
        .date = "20170703",
        .major = 1,
        .minor = 0,
        .patchlevel = 0,
        .dumb_create = drm_gem_cma_dumb_create,
        .gem_free_object_unlocked = drm_gem_cma_free_object,
        .gem_vm_ops = &drm_gem_cma_vm_ops,

        .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
        .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
        .gem_prime_import = drm_gem_prime_import,
        .gem_prime_export = drm_gem_prime_export,
        .gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
        .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
        .gem_prime_vmap = drm_gem_cma_prime_vmap,
        .gem_prime_vunmap = drm_gem_cma_prime_vunmap,
        .gem_prime_mmap = drm_gem_cma_prime_mmap,
};

static int tve200_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct tve200_drm_dev_private *priv;
        struct drm_device *drm;
        struct resource *res;
        int irq;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        drm = drm_dev_alloc(&tve200_drm_driver, dev);
        if (IS_ERR(drm))
                return PTR_ERR(drm);
        platform_set_drvdata(pdev, drm);
        priv->drm = drm;
        drm->dev_private = priv;

        /* Clock the silicon so we can access the registers */
        priv->pclk = devm_clk_get(dev, "PCLK");
        if (IS_ERR(priv->pclk)) {
                dev_err(dev, "unable to get PCLK\n");
                ret = PTR_ERR(priv->pclk);
                goto dev_unref;
        }
        ret = clk_prepare_enable(priv->pclk);
        if (ret) {
                dev_err(dev, "failed to enable PCLK\n");
                goto dev_unref;
        }

        /* This clock is for the pixels (27MHz) */
        priv->clk = devm_clk_get(dev, "TVE");
        if (IS_ERR(priv->clk)) {
                dev_err(dev, "unable to get TVE clock\n");
                ret = PTR_ERR(priv->clk);
                goto clk_disable;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        priv->regs = devm_ioremap_resource(dev, res);
        if (IS_ERR(priv->regs)) {
                dev_err(dev, "%s failed mmio\n", __func__);
                ret = -EINVAL;
                goto clk_disable;
        }

        irq = platform_get_irq(pdev, 0);
        if (!irq) {
                ret = -EINVAL;
                goto clk_disable;
        }

        /* turn off interrupts before requesting the irq */
        writel(0, priv->regs + TVE200_INT_EN);

        ret = devm_request_irq(dev, irq, tve200_irq, 0, "tve200", priv);
        if (ret) {
                dev_err(dev, "failed to request irq %d\n", ret);
                goto clk_disable;
        }

        ret = tve200_modeset_init(drm);
        if (ret)
                goto clk_disable;

        ret = drm_dev_register(drm, 0);
        if (ret < 0)
                goto clk_disable;

        return 0;

clk_disable:
        clk_disable_unprepare(priv->pclk);
dev_unref:
        drm_dev_unref(drm);
        return ret;
}

static int tve200_remove(struct platform_device *pdev)
{
        struct drm_device *drm = platform_get_drvdata(pdev);
        struct tve200_drm_dev_private *priv = drm->dev_private;

        drm_dev_unregister(drm);
        drm_fb_cma_fbdev_fini(drm);
        if (priv->panel)
                drm_panel_bridge_remove(priv->bridge);
        drm_mode_config_cleanup(drm);
        clk_disable_unprepare(priv->pclk);
        drm_dev_unref(drm);

        return 0;
}

static const struct of_device_id tve200_of_match[] = {
        {
                .compatible = "faraday,tve200",
        },
        {},
};

static struct platform_driver tve200_driver = {
        .driver = {
                .name           = "tve200",
                .of_match_table = of_match_ptr(tve200_of_match),
        },
        .probe = tve200_probe,
        .remove = tve200_remove,
};
module_platform_driver(tve200_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_LICENSE("GPL");