/*
 * Copyright (C) 2015 Free Electrons
 * Copyright (C) 2015 NextThing Co
 *
 * Maxime Ripard <maxime.ripard@free-electrons.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 */

#include <drm/drmP.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_encoder.h>
#include <drm/drm_modes.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>

#include <uapi/drm/drm_mode.h>

#include <linux/component.h>
#include <linux/ioport.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/regmap.h>
#include <linux/reset.h>

#include "sun4i_crtc.h"
#include "sun4i_dotclock.h"
#include "sun4i_drv.h"
#include "sun4i_lvds.h"
#include "sun4i_rgb.h"
#include "sun4i_tcon.h"
#include "sunxi_engine.h"

static struct drm_connector *sun4i_tcon_get_connector(const struct drm_encoder *encoder)
{
        struct drm_connector *connector;
        struct drm_connector_list_iter iter;

        drm_connector_list_iter_begin(encoder->dev, &iter);
        drm_for_each_connector_iter(connector, &iter)
                if (connector->encoder == encoder) {
                        drm_connector_list_iter_end(&iter);
                        return connector;
                }
        drm_connector_list_iter_end(&iter);

        return NULL;
}

static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
{
        struct drm_connector *connector;
        struct drm_display_info *info;

        connector = sun4i_tcon_get_connector(encoder);
        if (!connector)
                return -EINVAL;

        info = &connector->display_info;
        if (info->num_bus_formats != 1)
                return -EINVAL;

        switch (info->bus_formats[0]) {
        case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
                return 18;

        case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
        case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
                return 24;
        }

        return -EINVAL;
}

static void sun4i_tcon_channel_set_status(struct sun4i_tcon *tcon, int channel,
                                          bool enabled)
{
        struct clk *clk;

        switch (channel) {
        case 0:
                WARN_ON(!tcon->quirks->has_channel_0);
                regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
                                   SUN4I_TCON0_CTL_TCON_ENABLE,
                                   enabled ? SUN4I_TCON0_CTL_TCON_ENABLE : 0);
                clk = tcon->dclk;
                break;
        case 1:
                WARN_ON(!tcon->quirks->has_channel_1);
                regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
                                   SUN4I_TCON1_CTL_TCON_ENABLE,
                                   enabled ? SUN4I_TCON1_CTL_TCON_ENABLE : 0);
                clk = tcon->sclk1;
                break;
        default:
                DRM_WARN("Unknown channel... doing nothing\n");
                return;
        }

        if (enabled) {
                clk_prepare_enable(clk);
                clk_rate_exclusive_get(clk);
        } else {
                clk_rate_exclusive_put(clk);
                clk_disable_unprepare(clk);
        }
}

static void sun4i_tcon_lvds_set_status(struct sun4i_tcon *tcon,
                                       const struct drm_encoder *encoder,
                                       bool enabled)
{
        if (enabled) {
                u8 val;

                regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
                                   SUN4I_TCON0_LVDS_IF_EN,
                                   SUN4I_TCON0_LVDS_IF_EN);

                /*
                 * As their name suggest, these values only apply to the A31
                 * and later SoCs. We'll have to rework this when merging
                 * support for the older SoCs.
                 */
                regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
                             SUN6I_TCON0_LVDS_ANA0_C(2) |
                             SUN6I_TCON0_LVDS_ANA0_V(3) |
                             SUN6I_TCON0_LVDS_ANA0_PD(2) |
                             SUN6I_TCON0_LVDS_ANA0_EN_LDO);
                udelay(2);

                regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
                                   SUN6I_TCON0_LVDS_ANA0_EN_MB,
                                   SUN6I_TCON0_LVDS_ANA0_EN_MB);
                udelay(2);

                regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
                                   SUN6I_TCON0_LVDS_ANA0_EN_DRVC,
                                   SUN6I_TCON0_LVDS_ANA0_EN_DRVC);

                if (sun4i_tcon_get_pixel_depth(encoder) == 18)
                        val = 7;
                else
                        val = 0xf;

                regmap_write_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
                                  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(0xf),
                                  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
        } else {
                regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
                                   SUN4I_TCON0_LVDS_IF_EN, 0);
        }
}

void sun4i_tcon_set_status(struct sun4i_tcon *tcon,
                           const struct drm_encoder *encoder,
                           bool enabled)
{
        bool is_lvds = false;
        int channel;

        switch (encoder->encoder_type) {
        case DRM_MODE_ENCODER_LVDS:
                is_lvds = true;
                /* Fallthrough */
        case DRM_MODE_ENCODER_NONE:
                channel = 0;
                break;
        case DRM_MODE_ENCODER_TMDS:
        case DRM_MODE_ENCODER_TVDAC:
                channel = 1;
                break;
        default:
                DRM_DEBUG_DRIVER("Unknown encoder type, doing nothing...\n");
                return;
        }

        if (is_lvds && !enabled)
                sun4i_tcon_lvds_set_status(tcon, encoder, false);

        regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
                           SUN4I_TCON_GCTL_TCON_ENABLE,
                           enabled ? SUN4I_TCON_GCTL_TCON_ENABLE : 0);

        if (is_lvds && enabled)
                sun4i_tcon_lvds_set_status(tcon, encoder, true);

        sun4i_tcon_channel_set_status(tcon, channel, enabled);
}

void sun4i_tcon_enable_vblank(struct sun4i_tcon *tcon, bool enable)
{
        u32 mask, val = 0;

        DRM_DEBUG_DRIVER("%sabling VBLANK interrupt\n", enable ? "En" : "Dis");

        mask = SUN4I_TCON_GINT0_VBLANK_ENABLE(0) |
               SUN4I_TCON_GINT0_VBLANK_ENABLE(1);

        if (enable)
                val = mask;

        regmap_update_bits(tcon->regs, SUN4I_TCON_GINT0_REG, mask, val);
}
EXPORT_SYMBOL(sun4i_tcon_enable_vblank);

/*
 * This function is a helper for TCON output muxing. The TCON output
 * muxing control register in earlier SoCs (without the TCON TOP block)
 * are located in TCON0. This helper returns a pointer to TCON0's
 * sun4i_tcon structure, or NULL if not found.
 */
static struct sun4i_tcon *sun4i_get_tcon0(struct drm_device *drm)
{
        struct sun4i_drv *drv = drm->dev_private;
        struct sun4i_tcon *tcon;

        list_for_each_entry(tcon, &drv->tcon_list, list)
                if (tcon->id == 0)
                        return tcon;

        dev_warn(drm->dev,
                 "TCON0 not found, display output muxing may not work\n");

        return NULL;
}

void sun4i_tcon_set_mux(struct sun4i_tcon *tcon, int channel,
                        const struct drm_encoder *encoder)
{
        int ret = -ENOTSUPP;

        if (tcon->quirks->set_mux)
                ret = tcon->quirks->set_mux(tcon, encoder);

        DRM_DEBUG_DRIVER("Muxing encoder %s to CRTC %s: %d\n",
                         encoder->name, encoder->crtc->name, ret);
}

static int sun4i_tcon_get_clk_delay(const struct drm_display_mode *mode,
                                    int channel)
{
        int delay = mode->vtotal - mode->vdisplay;

        if (mode->flags & DRM_MODE_FLAG_INTERLACE)
                delay /= 2;

        if (channel == 1)
                delay -= 2;

        delay = min(delay, 30);

        DRM_DEBUG_DRIVER("TCON %d clock delay %u\n", channel, delay);

        return delay;
}

static void sun4i_tcon0_mode_set_common(struct sun4i_tcon *tcon,
                                        const struct drm_display_mode *mode)
{
        /* Configure the dot clock */
        clk_set_rate(tcon->dclk, mode->crtc_clock * 1000);

        /* Set the resolution */
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC0_REG,
                     SUN4I_TCON0_BASIC0_X(mode->crtc_hdisplay) |
                     SUN4I_TCON0_BASIC0_Y(mode->crtc_vdisplay));
}

static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon *tcon,
                                      const struct drm_encoder *encoder,
                                      const struct drm_display_mode *mode)
{
        unsigned int bp;
        u8 clk_delay;
        u32 reg, val = 0;

        WARN_ON(!tcon->quirks->has_channel_0);

        tcon->dclk_min_div = 7;
        tcon->dclk_max_div = 7;
        sun4i_tcon0_mode_set_common(tcon, mode);

        /* Adjust clock delay */
        clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
        regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
                           SUN4I_TCON0_CTL_CLK_DELAY_MASK,
                           SUN4I_TCON0_CTL_CLK_DELAY(clk_delay));

        /*
         * This is called a backporch in the register documentation,
         * but it really is the back porch + hsync
         */
        bp = mode->crtc_htotal - mode->crtc_hsync_start;
        DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
                         mode->crtc_htotal, bp);

        /* Set horizontal display timings */
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC1_REG,
                     SUN4I_TCON0_BASIC1_H_TOTAL(mode->htotal) |
                     SUN4I_TCON0_BASIC1_H_BACKPORCH(bp));

        /*
         * This is called a backporch in the register documentation,
         * but it really is the back porch + hsync
         */
        bp = mode->crtc_vtotal - mode->crtc_vsync_start;
        DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
                         mode->crtc_vtotal, bp);

        /* Set vertical display timings */
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC2_REG,
                     SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
                     SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));

        reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0 |
                SUN4I_TCON0_LVDS_IF_DATA_POL_NORMAL |
                SUN4I_TCON0_LVDS_IF_CLK_POL_NORMAL;
        if (sun4i_tcon_get_pixel_depth(encoder) == 24)
                reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS;
        else
                reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_18BITS;

        regmap_write(tcon->regs, SUN4I_TCON0_LVDS_IF_REG, reg);

        /* Setup the polarity of the various signals */
        if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
                val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE;

        if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
                val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE;

        regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val);

        /* Map output pins to channel 0 */
        regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
                           SUN4I_TCON_GCTL_IOMAP_MASK,
                           SUN4I_TCON_GCTL_IOMAP_TCON0);

        /* Enable the output on the pins */
        regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, 0xe0000000);
}

static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon,
                                     const struct drm_display_mode *mode)
{
        struct drm_panel *panel = tcon->panel;
        struct drm_connector *connector = panel->connector;
        struct drm_display_info display_info = connector->display_info;
        unsigned int bp, hsync, vsync;
        u8 clk_delay;
        u32 val = 0;

        WARN_ON(!tcon->quirks->has_channel_0);

        tcon->dclk_min_div = 6;
        tcon->dclk_max_div = 127;
        sun4i_tcon0_mode_set_common(tcon, mode);

        /* Adjust clock delay */
        clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
        regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
                           SUN4I_TCON0_CTL_CLK_DELAY_MASK,
                           SUN4I_TCON0_CTL_CLK_DELAY(clk_delay));

        /*
         * This is called a backporch in the register documentation,
         * but it really is the back porch + hsync
         */
        bp = mode->crtc_htotal - mode->crtc_hsync_start;
        DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
                         mode->crtc_htotal, bp);

        /* Set horizontal display timings */
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC1_REG,
                     SUN4I_TCON0_BASIC1_H_TOTAL(mode->crtc_htotal) |
                     SUN4I_TCON0_BASIC1_H_BACKPORCH(bp));

        /*
         * This is called a backporch in the register documentation,
         * but it really is the back porch + hsync
         */
        bp = mode->crtc_vtotal - mode->crtc_vsync_start;
        DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
                         mode->crtc_vtotal, bp);

        /* Set vertical display timings */
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC2_REG,
                     SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
                     SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));

        /* Set Hsync and Vsync length */
        hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
        vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
        DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
        regmap_write(tcon->regs, SUN4I_TCON0_BASIC3_REG,
                     SUN4I_TCON0_BASIC3_V_SYNC(vsync) |
                     SUN4I_TCON0_BASIC3_H_SYNC(hsync));

        /* Setup the polarity of the various signals */
        if (mode->flags & DRM_MODE_FLAG_PHSYNC)
                val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE;

        if (mode->flags & DRM_MODE_FLAG_PVSYNC)
                val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE;

        /*
         * On A20 and similar SoCs, the only way to achieve Positive Edge
         * (Rising Edge), is setting dclk clock phase to 2/3(240°).
         * By default TCON works in Negative Edge(Falling Edge),
         * this is why phase is set to 0 in that case.
         * Unfortunately there's no way to logically invert dclk through
         * IO_POL register.
         * The only acceptable way to work, triple checked with scope,
         * is using clock phase set to 0° for Negative Edge and set to 240°
         * for Positive Edge.
         * On A33 and similar SoCs there would be a 90° phase option,
         * but it divides also dclk by 2.
         * Following code is a way to avoid quirks all around TCON
         * and DOTCLOCK drivers.
         */
        if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE)
                clk_set_phase(tcon->dclk, 240);

        if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE)
                clk_set_phase(tcon->dclk, 0);

        regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG,
                           SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE,
                           val);

        /* Map output pins to channel 0 */
        regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
                           SUN4I_TCON_GCTL_IOMAP_MASK,
                           SUN4I_TCON_GCTL_IOMAP_TCON0);

        /* Enable the output on the pins */
        regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, 0);
}

static void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
                                 const struct drm_display_mode *mode)
{
        unsigned int bp, hsync, vsync, vtotal;
        u8 clk_delay;
        u32 val;

        WARN_ON(!tcon->quirks->has_channel_1);

        /* Configure the dot clock */
        clk_set_rate(tcon->sclk1, mode->crtc_clock * 1000);

        /* Adjust clock delay */
        clk_delay = sun4i_tcon_get_clk_delay(mode, 1);
        regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
                           SUN4I_TCON1_CTL_CLK_DELAY_MASK,
                           SUN4I_TCON1_CTL_CLK_DELAY(clk_delay));

        /* Set interlaced mode */
        if (mode->flags & DRM_MODE_FLAG_INTERLACE)
                val = SUN4I_TCON1_CTL_INTERLACE_ENABLE;
        else
                val = 0;
        regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
                           SUN4I_TCON1_CTL_INTERLACE_ENABLE,
                           val);

        /* Set the input resolution */
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC0_REG,
                     SUN4I_TCON1_BASIC0_X(mode->crtc_hdisplay) |
                     SUN4I_TCON1_BASIC0_Y(mode->crtc_vdisplay));

        /* Set the upscaling resolution */
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC1_REG,
                     SUN4I_TCON1_BASIC1_X(mode->crtc_hdisplay) |
                     SUN4I_TCON1_BASIC1_Y(mode->crtc_vdisplay));

        /* Set the output resolution */
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC2_REG,
                     SUN4I_TCON1_BASIC2_X(mode->crtc_hdisplay) |
                     SUN4I_TCON1_BASIC2_Y(mode->crtc_vdisplay));

        /* Set horizontal display timings */
        bp = mode->crtc_htotal - mode->crtc_hsync_start;
        DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
                         mode->htotal, bp);
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC3_REG,
                     SUN4I_TCON1_BASIC3_H_TOTAL(mode->crtc_htotal) |
                     SUN4I_TCON1_BASIC3_H_BACKPORCH(bp));

        bp = mode->crtc_vtotal - mode->crtc_vsync_start;
        DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
                         mode->crtc_vtotal, bp);

        /*
         * The vertical resolution needs to be doubled in all
         * cases. We could use crtc_vtotal and always multiply by two,
         * but that leads to a rounding error in interlace when vtotal
         * is odd.
         *
         * This happens with TV's PAL for example, where vtotal will
         * be 625, crtc_vtotal 312, and thus crtc_vtotal * 2 will be
         * 624, which apparently confuses the hardware.
         *
         * To work around this, we will always use vtotal, and
         * multiply by two only if we're not in interlace.
         */
        vtotal = mode->vtotal;
        if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
                vtotal = vtotal * 2;

        /* Set vertical display timings */
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC4_REG,
                     SUN4I_TCON1_BASIC4_V_TOTAL(vtotal) |
                     SUN4I_TCON1_BASIC4_V_BACKPORCH(bp));

        /* Set Hsync and Vsync length */
        hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
        vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
        DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
        regmap_write(tcon->regs, SUN4I_TCON1_BASIC5_REG,
                     SUN4I_TCON1_BASIC5_V_SYNC(vsync) |
                     SUN4I_TCON1_BASIC5_H_SYNC(hsync));

        /* Map output pins to channel 1 */
        regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
                           SUN4I_TCON_GCTL_IOMAP_MASK,
                           SUN4I_TCON_GCTL_IOMAP_TCON1);
}

void sun4i_tcon_mode_set(struct sun4i_tcon *tcon,
                         const struct drm_encoder *encoder,
                         const struct drm_display_mode *mode)
{
        switch (encoder->encoder_type) {
        case DRM_MODE_ENCODER_LVDS:
                sun4i_tcon0_mode_set_lvds(tcon, encoder, mode);
                break;
        case DRM_MODE_ENCODER_NONE:
                sun4i_tcon0_mode_set_rgb(tcon, mode);
                sun4i_tcon_set_mux(tcon, 0, encoder);
                break;
        case DRM_MODE_ENCODER_TVDAC:
        case DRM_MODE_ENCODER_TMDS:
                sun4i_tcon1_mode_set(tcon, mode);
                sun4i_tcon_set_mux(tcon, 1, encoder);
                break;
        default:
                DRM_DEBUG_DRIVER("Unknown encoder type, doing nothing...\n");
        }
}
EXPORT_SYMBOL(sun4i_tcon_mode_set);

static void sun4i_tcon_finish_page_flip(struct drm_device *dev,
                                        struct sun4i_crtc *scrtc)
{
        unsigned long flags;

        spin_lock_irqsave(&dev->event_lock, flags);
        if (scrtc->event) {
                drm_crtc_send_vblank_event(&scrtc->crtc, scrtc->event);
                drm_crtc_vblank_put(&scrtc->crtc);
                scrtc->event = NULL;
        }
        spin_unlock_irqrestore(&dev->event_lock, flags);
}

static irqreturn_t sun4i_tcon_handler(int irq, void *private)
{
        struct sun4i_tcon *tcon = private;
        struct drm_device *drm = tcon->drm;
        struct sun4i_crtc *scrtc = tcon->crtc;
        struct sunxi_engine *engine = scrtc->engine;
        unsigned int status;

        regmap_read(tcon->regs, SUN4I_TCON_GINT0_REG, &status);

        if (!(status & (SUN4I_TCON_GINT0_VBLANK_INT(0) |
                        SUN4I_TCON_GINT0_VBLANK_INT(1))))
                return IRQ_NONE;

        drm_crtc_handle_vblank(&scrtc->crtc);
        sun4i_tcon_finish_page_flip(drm, scrtc);

        /* Acknowledge the interrupt */
        regmap_update_bits(tcon->regs, SUN4I_TCON_GINT0_REG,
                           SUN4I_TCON_GINT0_VBLANK_INT(0) |
                           SUN4I_TCON_GINT0_VBLANK_INT(1),
                           0);

        if (engine->ops->vblank_quirk)
                engine->ops->vblank_quirk(engine);

        return IRQ_HANDLED;
}

static int sun4i_tcon_init_clocks(struct device *dev,
                                  struct sun4i_tcon *tcon)
{
        tcon->clk = devm_clk_get(dev, "ahb");
        if (IS_ERR(tcon->clk)) {
                dev_err(dev, "Couldn't get the TCON bus clock\n");
                return PTR_ERR(tcon->clk);
        }
        clk_prepare_enable(tcon->clk);

        if (tcon->quirks->has_channel_0) {
                tcon->sclk0 = devm_clk_get(dev, "tcon-ch0");
                if (IS_ERR(tcon->sclk0)) {
                        dev_err(dev, "Couldn't get the TCON channel 0 clock\n");
                        return PTR_ERR(tcon->sclk0);
                }
        }

        if (tcon->quirks->has_channel_1) {
                tcon->sclk1 = devm_clk_get(dev, "tcon-ch1");
                if (IS_ERR(tcon->sclk1)) {
                        dev_err(dev, "Couldn't get the TCON channel 1 clock\n");
                        return PTR_ERR(tcon->sclk1);
                }
        }

        return 0;
}

static void sun4i_tcon_free_clocks(struct sun4i_tcon *tcon)
{
        clk_disable_unprepare(tcon->clk);
}

static int sun4i_tcon_init_irq(struct device *dev,
                               struct sun4i_tcon *tcon)
{
        struct platform_device *pdev = to_platform_device(dev);
        int irq, ret;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(dev, "Couldn't retrieve the TCON interrupt\n");
                return irq;
        }

        ret = devm_request_irq(dev, irq, sun4i_tcon_handler, 0,
                               dev_name(dev), tcon);
        if (ret) {
                dev_err(dev, "Couldn't request the IRQ\n");
                return ret;
        }

        return 0;
}

static struct regmap_config sun4i_tcon_regmap_config = {
        .reg_bits       = 32,
        .val_bits       = 32,
        .reg_stride     = 4,
        .max_register   = 0x800,
};

static int sun4i_tcon_init_regmap(struct device *dev,
                                  struct sun4i_tcon *tcon)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct resource *res;
        void __iomem *regs;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        regs = devm_ioremap_resource(dev, res);
        if (IS_ERR(regs))
                return PTR_ERR(regs);

        tcon->regs = devm_regmap_init_mmio(dev, regs,
                                           &sun4i_tcon_regmap_config);
        if (IS_ERR(tcon->regs)) {
                dev_err(dev, "Couldn't create the TCON regmap\n");
                return PTR_ERR(tcon->regs);
        }

        /* Make sure the TCON is disabled and all IRQs are off */
        regmap_write(tcon->regs, SUN4I_TCON_GCTL_REG, 0);
        regmap_write(tcon->regs, SUN4I_TCON_GINT0_REG, 0);
        regmap_write(tcon->regs, SUN4I_TCON_GINT1_REG, 0);

        /* Disable IO lines and set them to tristate */
        regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, ~0);
        regmap_write(tcon->regs, SUN4I_TCON1_IO_TRI_REG, ~0);

        return 0;
}

/*
 * On SoCs with the old display pipeline design (Display Engine 1.0),
 * the TCON is always tied to just one backend. Hence we can traverse
 * the of_graph upwards to find the backend our tcon is connected to,
 * and take its ID as our own.
 *
 * We can either identify backends from their compatible strings, which
 * means maintaining a large list of them. Or, since the backend is
 * registered and binded before the TCON, we can just go through the
 * list of registered backends and compare the device node.
 *
 * As the structures now store engines instead of backends, here this
 * function in fact searches the corresponding engine, and the ID is
 * requested via the get_id function of the engine.
 */
static struct sunxi_engine *
sun4i_tcon_find_engine_traverse(struct sun4i_drv *drv,
                                struct device_node *node)
{
        struct device_node *port, *ep, *remote;
        struct sunxi_engine *engine = ERR_PTR(-EINVAL);

        port = of_graph_get_port_by_id(node, 0);
        if (!port)
                return ERR_PTR(-EINVAL);

        /*
         * This only works if there is only one path from the TCON
         * to any display engine. Otherwise the probe order of the
         * TCONs and display engines is not guaranteed. They may
         * either bind to the wrong one, or worse, bind to the same
         * one if additional checks are not done.
         *
         * Bail out if there are multiple input connections.
         */
        if (of_get_available_child_count(port) != 1)
                goto out_put_port;

        /* Get the first connection without specifying an ID */
        ep = of_get_next_available_child(port, NULL);
        if (!ep)
                goto out_put_port;

        remote = of_graph_get_remote_port_parent(ep);
        if (!remote)
                goto out_put_ep;

        /* does this node match any registered engines? */
        list_for_each_entry(engine, &drv->engine_list, list)
                if (remote == engine->node)
                        goto out_put_remote;

        /* keep looking through upstream ports */
        engine = sun4i_tcon_find_engine_traverse(drv, remote);

out_put_remote:
        of_node_put(remote);
out_put_ep:
        of_node_put(ep);
out_put_port:
        of_node_put(port);

        return engine;
}

/*
 * The device tree binding says that the remote endpoint ID of any
 * connection between components, up to and including the TCON, of
 * the display pipeline should be equal to the actual ID of the local
 * component. Thus we can look at any one of the input connections of
 * the TCONs, and use that connection's remote endpoint ID as our own.
 *
 * Since the user of this function already finds the input port,
 * the port is passed in directly without further checks.
 */
static int sun4i_tcon_of_get_id_from_port(struct device_node *port)
{
        struct device_node *ep;
        int ret = -EINVAL;

        /* try finding an upstream endpoint */
        for_each_available_child_of_node(port, ep) {
                struct device_node *remote;
                u32 reg;

                remote = of_graph_get_remote_endpoint(ep);
                if (!remote)
                        continue;

                ret = of_property_read_u32(remote, "reg", &reg);
                if (ret)
                        continue;

                ret = reg;
        }

        return ret;
}

/*
 * Once we know the TCON's id, we can look through the list of
 * engines to find a matching one. We assume all engines have
 * been probed and added to the list.
 */
static struct sunxi_engine *sun4i_tcon_get_engine_by_id(struct sun4i_drv *drv,
                                                        int id)
{
        struct sunxi_engine *engine;

        list_for_each_entry(engine, &drv->engine_list, list)
                if (engine->id == id)
                        return engine;

        return ERR_PTR(-EINVAL);
}

/*
 * On SoCs with the old display pipeline design (Display Engine 1.0),
 * we assumed the TCON was always tied to just one backend. However
 * this proved not to be the case. On the A31, the TCON can select
 * either backend as its source. On the A20 (and likely on the A10),
 * the backend can choose which TCON to output to.
 *
 * The device tree binding says that the remote endpoint ID of any
 * connection between components, up to and including the TCON, of
 * the display pipeline should be equal to the actual ID of the local
 * component. Thus we should be able to look at any one of the input
 * connections of the TCONs, and use that connection's remote endpoint
 * ID as our own.
 *
 * However  the connections between the backend and TCON were assumed
 * to be always singular, and their endpoit IDs were all incorrectly
 * set to 0. This means for these old device trees, we cannot just look
 * up the remote endpoint ID of a TCON input endpoint. TCON1 would be
 * incorrectly identified as TCON0.
 *
 * This function first checks if the TCON node has 2 input endpoints.
 * If so, then the device tree is a corrected version, and it will use
 * sun4i_tcon_of_get_id() and sun4i_tcon_get_engine_by_id() from above
 * to fetch the ID and engine directly. If not, then it is likely an
 * old device trees, where the endpoint IDs were incorrect, but did not
 * have endpoint connections between the backend and TCON across
 * different display pipelines. It will fall back to the old method of
 * traversing the  of_graph to try and find a matching engine by device
 * node.
 *
 * In the case of single display pipeline device trees, either method
 * works.
 */
static struct sunxi_engine *sun4i_tcon_find_engine(struct sun4i_drv *drv,
                                                   struct device_node *node)
{
        struct device_node *port;
        struct sunxi_engine *engine;

        port = of_graph_get_port_by_id(node, 0);
        if (!port)
                return ERR_PTR(-EINVAL);

        /*
         * Is this a corrected device tree with cross pipeline
         * connections between the backend and TCON?
         */
        if (of_get_child_count(port) > 1) {
                /* Get our ID directly from an upstream endpoint */
                int id = sun4i_tcon_of_get_id_from_port(port);

                /* Get our engine by matching our ID */
                engine = sun4i_tcon_get_engine_by_id(drv, id);

                of_node_put(port);
                return engine;
        }

        /* Fallback to old method by traversing input endpoints */
        of_node_put(port);
        return sun4i_tcon_find_engine_traverse(drv, node);
}

static int sun4i_tcon_bind(struct device *dev, struct device *master,
                           void *data)
{
        struct drm_device *drm = data;
        struct sun4i_drv *drv = drm->dev_private;
        struct sunxi_engine *engine;
        struct device_node *remote;
        struct sun4i_tcon *tcon;
        struct reset_control *edp_rstc;
        bool has_lvds_rst, has_lvds_alt, can_lvds;
        int ret;

        engine = sun4i_tcon_find_engine(drv, dev->of_node);
        if (IS_ERR(engine)) {
                dev_err(dev, "Couldn't find matching engine\n");
                return -EPROBE_DEFER;
        }

        tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
        if (!tcon)
                return -ENOMEM;
        dev_set_drvdata(dev, tcon);
        tcon->drm = drm;
        tcon->dev = dev;
        tcon->id = engine->id;
        tcon->quirks = of_device_get_match_data(dev);

        tcon->lcd_rst = devm_reset_control_get(dev, "lcd");
        if (IS_ERR(tcon->lcd_rst)) {
                dev_err(dev, "Couldn't get our reset line\n");
                return PTR_ERR(tcon->lcd_rst);
        }

        if (tcon->quirks->needs_edp_reset) {
                edp_rstc = devm_reset_control_get_shared(dev, "edp");
                if (IS_ERR(edp_rstc)) {
                        dev_err(dev, "Couldn't get edp reset line\n");
                        return PTR_ERR(edp_rstc);
                }

                ret = reset_control_deassert(edp_rstc);
                if (ret) {
                        dev_err(dev, "Couldn't deassert edp reset line\n");
                        return ret;
                }
        }

        /* Make sure our TCON is reset */
        ret = reset_control_reset(tcon->lcd_rst);
        if (ret) {
                dev_err(dev, "Couldn't deassert our reset line\n");
                return ret;
        }

        if (tcon->quirks->supports_lvds) {
                /*
                 * This can only be made optional since we've had DT
                 * nodes without the LVDS reset properties.
                 *
                 * If the property is missing, just disable LVDS, and
                 * print a warning.
                 */
                tcon->lvds_rst = devm_reset_control_get_optional(dev, "lvds");
                if (IS_ERR(tcon->lvds_rst)) {
                        dev_err(dev, "Couldn't get our reset line\n");
                        return PTR_ERR(tcon->lvds_rst);
                } else if (tcon->lvds_rst) {
                        has_lvds_rst = true;
                        reset_control_reset(tcon->lvds_rst);
                } else {
                        has_lvds_rst = false;
                }

                /*
                 * This can only be made optional since we've had DT
                 * nodes without the LVDS reset properties.
                 *
                 * If the property is missing, just disable LVDS, and
                 * print a warning.
                 */
                if (tcon->quirks->has_lvds_alt) {
                        tcon->lvds_pll = devm_clk_get(dev, "lvds-alt");
                        if (IS_ERR(tcon->lvds_pll)) {
                                if (PTR_ERR(tcon->lvds_pll) == -ENOENT) {
                                        has_lvds_alt = false;
                                } else {
                                        dev_err(dev, "Couldn't get the LVDS PLL\n");
                                        return PTR_ERR(tcon->lvds_pll);
                                }
                        } else {
                                has_lvds_alt = true;
                        }
                }

                if (!has_lvds_rst ||
                    (tcon->quirks->has_lvds_alt && !has_lvds_alt)) {
                        dev_warn(dev, "Missing LVDS properties, Please upgrade your DT\n");
                        dev_warn(dev, "LVDS output disabled\n");
                        can_lvds = false;
                } else {
                        can_lvds = true;
                }
        } else {
                can_lvds = false;
        }

        ret = sun4i_tcon_init_clocks(dev, tcon);
        if (ret) {
                dev_err(dev, "Couldn't init our TCON clocks\n");
                goto err_assert_reset;
        }

        ret = sun4i_tcon_init_regmap(dev, tcon);
        if (ret) {
                dev_err(dev, "Couldn't init our TCON regmap\n");
                goto err_free_clocks;
        }

        if (tcon->quirks->has_channel_0) {
                ret = sun4i_dclk_create(dev, tcon);
                if (ret) {
                        dev_err(dev, "Couldn't create our TCON dot clock\n");
                        goto err_free_clocks;
                }
        }

        ret = sun4i_tcon_init_irq(dev, tcon);
        if (ret) {
                dev_err(dev, "Couldn't init our TCON interrupts\n");
                goto err_free_dotclock;
        }

        tcon->crtc = sun4i_crtc_init(drm, engine, tcon);
        if (IS_ERR(tcon->crtc)) {
                dev_err(dev, "Couldn't create our CRTC\n");
                ret = PTR_ERR(tcon->crtc);
                goto err_free_dotclock;
        }

        /*
         * If we have an LVDS panel connected to the TCON, we should
         * just probe the LVDS connector. Otherwise, just probe RGB as
         * we used to.
         */
        remote = of_graph_get_remote_node(dev->of_node, 1, 0);
        if (of_device_is_compatible(remote, "panel-lvds"))
                if (can_lvds)
                        ret = sun4i_lvds_init(drm, tcon);
                else
                        ret = -EINVAL;
        else
                ret = sun4i_rgb_init(drm, tcon);
        of_node_put(remote);

        if (ret < 0)
                goto err_free_dotclock;

        if (tcon->quirks->needs_de_be_mux) {
                /*
                 * We assume there is no dynamic muxing of backends
                 * and TCONs, so we select the backend with same ID.
                 *
                 * While dynamic selection might be interesting, since
                 * the CRTC is tied to the TCON, while the layers are
                 * tied to the backends, this means, we will need to
                 * switch between groups of layers. There might not be
                 * a way to represent this constraint in DRM.
                 */
                regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
                                   SUN4I_TCON0_CTL_SRC_SEL_MASK,
                                   tcon->id);
                regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
                                   SUN4I_TCON1_CTL_SRC_SEL_MASK,
                                   tcon->id);
        }

        list_add_tail(&tcon->list, &drv->tcon_list);

        return 0;

err_free_dotclock:
        if (tcon->quirks->has_channel_0)
                sun4i_dclk_free(tcon);
err_free_clocks:
        sun4i_tcon_free_clocks(tcon);
err_assert_reset:
        reset_control_assert(tcon->lcd_rst);
        return ret;
}

static void sun4i_tcon_unbind(struct device *dev, struct device *master,
                              void *data)
{
        struct sun4i_tcon *tcon = dev_get_drvdata(dev);

        list_del(&tcon->list);
        if (tcon->quirks->has_channel_0)
                sun4i_dclk_free(tcon);
        sun4i_tcon_free_clocks(tcon);
}

static const struct component_ops sun4i_tcon_ops = {
        .bind   = sun4i_tcon_bind,
        .unbind = sun4i_tcon_unbind,
};

static int sun4i_tcon_probe(struct platform_device *pdev)
{
        struct device_node *node = pdev->dev.of_node;
        struct drm_bridge *bridge;
        struct drm_panel *panel;
        int ret;

        ret = drm_of_find_panel_or_bridge(node, 1, 0, &panel, &bridge);
        if (ret == -EPROBE_DEFER)
                return ret;

        return component_add(&pdev->dev, &sun4i_tcon_ops);
}

static int sun4i_tcon_remove(struct platform_device *pdev)
{
        component_del(&pdev->dev, &sun4i_tcon_ops);

        return 0;
}

/* platform specific TCON muxing callbacks */
static int sun4i_a10_tcon_set_mux(struct sun4i_tcon *tcon,
                                  const struct drm_encoder *encoder)
{
        struct sun4i_tcon *tcon0 = sun4i_get_tcon0(encoder->dev);
        u32 shift;

        if (!tcon0)
                return -EINVAL;

        switch (encoder->encoder_type) {
        case DRM_MODE_ENCODER_TMDS:
                /* HDMI */
                shift = 8;
                break;
        default:
                return -EINVAL;
        }

        regmap_update_bits(tcon0->regs, SUN4I_TCON_MUX_CTRL_REG,
                           0x3 << shift, tcon->id << shift);

        return 0;
}

static int sun5i_a13_tcon_set_mux(struct sun4i_tcon *tcon,
                                  const struct drm_encoder *encoder)
{
        u32 val;

        if (encoder->encoder_type == DRM_MODE_ENCODER_TVDAC)
                val = 1;
        else
                val = 0;

        /*
         * FIXME: Undocumented bits
         */
        return regmap_write(tcon->regs, SUN4I_TCON_MUX_CTRL_REG, val);
}

static int sun6i_tcon_set_mux(struct sun4i_tcon *tcon,
                              const struct drm_encoder *encoder)
{
        struct sun4i_tcon *tcon0 = sun4i_get_tcon0(encoder->dev);
        u32 shift;

        if (!tcon0)
                return -EINVAL;

        switch (encoder->encoder_type) {
        case DRM_MODE_ENCODER_TMDS:
                /* HDMI */
                shift = 8;
                break;
        default:
                /* TODO A31 has MIPI DSI but A31s does not */
                return -EINVAL;
        }

        regmap_update_bits(tcon0->regs, SUN4I_TCON_MUX_CTRL_REG,
                           0x3 << shift, tcon->id << shift);

        return 0;
}

static const struct sun4i_tcon_quirks sun4i_a10_quirks = {
        .has_channel_0          = true,
        .has_channel_1          = true,
        .set_mux                = sun4i_a10_tcon_set_mux,
};

static const struct sun4i_tcon_quirks sun5i_a13_quirks = {
        .has_channel_0          = true,
        .has_channel_1          = true,
        .set_mux                = sun5i_a13_tcon_set_mux,
};

static const struct sun4i_tcon_quirks sun6i_a31_quirks = {
        .has_channel_0          = true,
        .has_channel_1          = true,
        .has_lvds_alt           = true,
        .needs_de_be_mux        = true,
        .set_mux                = sun6i_tcon_set_mux,
};

static const struct sun4i_tcon_quirks sun6i_a31s_quirks = {
        .has_channel_0          = true,
        .has_channel_1          = true,
        .needs_de_be_mux        = true,
};

static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
        .has_channel_0          = true,
        .has_channel_1          = true,
        /* Same display pipeline structure as A10 */
        .set_mux                = sun4i_a10_tcon_set_mux,
};

static const struct sun4i_tcon_quirks sun8i_a33_quirks = {
        .has_channel_0          = true,
        .has_lvds_alt           = true,
};

static const struct sun4i_tcon_quirks sun8i_a83t_lcd_quirks = {
        .supports_lvds          = true,
        .has_channel_0          = true,
};

static const struct sun4i_tcon_quirks sun8i_a83t_tv_quirks = {
        .has_channel_1          = true,
};

static const struct sun4i_tcon_quirks sun8i_v3s_quirks = {
        .has_channel_0          = true,
};

static const struct sun4i_tcon_quirks sun9i_a80_tcon_lcd_quirks = {
        .has_channel_0  = true,
        .needs_edp_reset = true,
};

static const struct sun4i_tcon_quirks sun9i_a80_tcon_tv_quirks = {
        .has_channel_1  = true,
        .needs_edp_reset = true,
};

/* sun4i_drv uses this list to check if a device node is a TCON */
const struct of_device_id sun4i_tcon_of_table[] = {
        { .compatible = "allwinner,sun4i-a10-tcon", .data = &sun4i_a10_quirks },
        { .compatible = "allwinner,sun5i-a13-tcon", .data = &sun5i_a13_quirks },
        { .compatible = "allwinner,sun6i-a31-tcon", .data = &sun6i_a31_quirks },
        { .compatible = "allwinner,sun6i-a31s-tcon", .data = &sun6i_a31s_quirks },
        { .compatible = "allwinner,sun7i-a20-tcon", .data = &sun7i_a20_quirks },
        { .compatible = "allwinner,sun8i-a33-tcon", .data = &sun8i_a33_quirks },
        { .compatible = "allwinner,sun8i-a83t-tcon-lcd", .data = &sun8i_a83t_lcd_quirks },
        { .compatible = "allwinner,sun8i-a83t-tcon-tv", .data = &sun8i_a83t_tv_quirks },
        { .compatible = "allwinner,sun8i-v3s-tcon", .data = &sun8i_v3s_quirks },
        { .compatible = "allwinner,sun9i-a80-tcon-lcd", .data = &sun9i_a80_tcon_lcd_quirks },
        { .compatible = "allwinner,sun9i-a80-tcon-tv", .data = &sun9i_a80_tcon_tv_quirks },
        { }
};
MODULE_DEVICE_TABLE(of, sun4i_tcon_of_table);
EXPORT_SYMBOL(sun4i_tcon_of_table);

static struct platform_driver sun4i_tcon_platform_driver = {
        .probe          = sun4i_tcon_probe,
        .remove         = sun4i_tcon_remove,
        .driver         = {
                .name           = "sun4i-tcon",
                .of_match_table = sun4i_tcon_of_table,
        },
};
module_platform_driver(sun4i_tcon_platform_driver);

MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_DESCRIPTION("Allwinner A10 Timing Controller Driver");
MODULE_LICENSE("GPL");