// SPDX-License-Identifier: GPL-2.0
/*
 * rcar_lvds.c  --  R-Car LVDS Encoder
 *
 * Copyright (C) 2013-2018 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_panel.h>
#include <drm/drm_probe_helper.h>

#include "rcar_lvds.h"
#include "rcar_lvds_regs.h"

struct rcar_lvds;

/* Keep in sync with the LVDCR0.LVMD hardware register values. */
enum rcar_lvds_mode {
        RCAR_LVDS_MODE_JEIDA = 0,
        RCAR_LVDS_MODE_MIRROR = 1,
        RCAR_LVDS_MODE_VESA = 4,
};

#define RCAR_LVDS_QUIRK_LANES           BIT(0)  /* LVDS lanes 1 and 3 inverted */
#define RCAR_LVDS_QUIRK_GEN3_LVEN       BIT(1)  /* LVEN bit needs to be set on R8A77970/R8A7799x */
#define RCAR_LVDS_QUIRK_PWD             BIT(2)  /* PWD bit available (all of Gen3 but E3) */
#define RCAR_LVDS_QUIRK_EXT_PLL         BIT(3)  /* Has extended PLL */
#define RCAR_LVDS_QUIRK_DUAL_LINK       BIT(4)  /* Supports dual-link operation */

struct rcar_lvds_device_info {
        unsigned int gen;
        unsigned int quirks;
        void (*pll_setup)(struct rcar_lvds *lvds, unsigned int freq);
};

struct rcar_lvds {
        struct device *dev;
        const struct rcar_lvds_device_info *info;

        struct drm_bridge bridge;

        struct drm_bridge *next_bridge;
        struct drm_connector connector;
        struct drm_panel *panel;

        void __iomem *mmio;
        struct {
                struct clk *mod;                /* CPG module clock */
                struct clk *extal;              /* External clock */
                struct clk *dotclkin[2];        /* External DU clocks */
        } clocks;

        struct drm_display_mode display_mode;
        enum rcar_lvds_mode mode;

        struct drm_bridge *companion;
        bool dual_link;
};

#define bridge_to_rcar_lvds(bridge) \
        container_of(bridge, struct rcar_lvds, bridge)

#define connector_to_rcar_lvds(connector) \
        container_of(connector, struct rcar_lvds, connector)

static void rcar_lvds_write(struct rcar_lvds *lvds, u32 reg, u32 data)
{
        iowrite32(data, lvds->mmio + reg);
}

/* -----------------------------------------------------------------------------
 * Connector & Panel
 */

static int rcar_lvds_connector_get_modes(struct drm_connector *connector)
{
        struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);

        return drm_panel_get_modes(lvds->panel);
}

static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
                                            struct drm_atomic_state *state)
{
        struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
        const struct drm_display_mode *panel_mode;
        struct drm_connector_state *conn_state;
        struct drm_crtc_state *crtc_state;

        conn_state = drm_atomic_get_new_connector_state(state, connector);
        if (!conn_state->crtc)
                return 0;

        if (list_empty(&connector->modes)) {
                dev_dbg(lvds->dev, "connector: empty modes list\n");
                return -EINVAL;
        }

        panel_mode = list_first_entry(&connector->modes,
                                      struct drm_display_mode, head);

        /* We're not allowed to modify the resolution. */
        crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
        if (IS_ERR(crtc_state))
                return PTR_ERR(crtc_state);

        if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
            crtc_state->mode.vdisplay != panel_mode->vdisplay)
                return -EINVAL;

        /* The flat panel mode is fixed, just copy it to the adjusted mode. */
        drm_mode_copy(&crtc_state->adjusted_mode, panel_mode);

        return 0;
}

static const struct drm_connector_helper_funcs rcar_lvds_conn_helper_funcs = {
        .get_modes = rcar_lvds_connector_get_modes,
        .atomic_check = rcar_lvds_connector_atomic_check,
};

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

/* -----------------------------------------------------------------------------
 * PLL Setup
 */

static void rcar_lvds_pll_setup_gen2(struct rcar_lvds *lvds, unsigned int freq)
{
        u32 val;

        if (freq < 39000000)
                val = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_38M;
        else if (freq < 61000000)
                val = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_60M;
        else if (freq < 121000000)
                val = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_121M;
        else
                val = LVDPLLCR_PLLDLYCNT_150M;

        rcar_lvds_write(lvds, LVDPLLCR, val);
}

static void rcar_lvds_pll_setup_gen3(struct rcar_lvds *lvds, unsigned int freq)
{
        u32 val;

        if (freq < 42000000)
                val = LVDPLLCR_PLLDIVCNT_42M;
        else if (freq < 85000000)
                val = LVDPLLCR_PLLDIVCNT_85M;
        else if (freq < 128000000)
                val = LVDPLLCR_PLLDIVCNT_128M;
        else
                val = LVDPLLCR_PLLDIVCNT_148M;

        rcar_lvds_write(lvds, LVDPLLCR, val);
}

struct pll_info {
        unsigned long diff;
        unsigned int pll_m;
        unsigned int pll_n;
        unsigned int pll_e;
        unsigned int div;
        u32 clksel;
};

static void rcar_lvds_d3_e3_pll_calc(struct rcar_lvds *lvds, struct clk *clk,
                                     unsigned long target, struct pll_info *pll,
                                     u32 clksel, bool dot_clock_only)
{
        unsigned int div7 = dot_clock_only ? 1 : 7;
        unsigned long output;
        unsigned long fin;
        unsigned int m_min;
        unsigned int m_max;
        unsigned int m;
        int error;

        if (!clk)
                return;

        /*
         * The LVDS PLL is made of a pre-divider and a multiplier (strangely
         * enough called M and N respectively), followed by a post-divider E.
         *
         *         ,-----.         ,-----.     ,-----.         ,-----.
         * Fin --> | 1/M | -Fpdf-> | PFD | --> | VCO | -Fvco-> | 1/E | --> Fout
         *         `-----'     ,-> |     |     `-----'   |     `-----'
         *                     |   `-----'               |
         *                     |         ,-----.         |
         *                     `-------- | 1/N | <-------'
         *                               `-----'
         *
         * The clock output by the PLL is then further divided by a programmable
         * divider DIV to achieve the desired target frequency. Finally, an
         * optional fixed /7 divider is used to convert the bit clock to a pixel
         * clock (as LVDS transmits 7 bits per lane per clock sample).
         *
         *          ,-------.     ,-----.     |\
         * Fout --> | 1/DIV | --> | 1/7 | --> | |
         *          `-------'  |  `-----'     | | --> dot clock
         *                     `------------> | |
         *                                    |/
         *
         * The /7 divider is optional, it is enabled when the LVDS PLL is used
         * to drive the LVDS encoder, and disabled when  used to generate a dot
         * clock for the DU RGB output, without using the LVDS encoder.
         *
         * The PLL allowed input frequency range is 12 MHz to 192 MHz.
         */

        fin = clk_get_rate(clk);
        if (fin < 12000000 || fin > 192000000)
                return;

        /*
         * The comparison frequency range is 12 MHz to 24 MHz, which limits the
         * allowed values for the pre-divider M (normal range 1-8).
         *
         * Fpfd = Fin / M
         */
        m_min = max_t(unsigned int, 1, DIV_ROUND_UP(fin, 24000000));
        m_max = min_t(unsigned int, 8, fin / 12000000);

        for (m = m_min; m <= m_max; ++m) {
                unsigned long fpfd;
                unsigned int n_min;
                unsigned int n_max;
                unsigned int n;

                /*
                 * The VCO operating range is 900 Mhz to 1800 MHz, which limits
                 * the allowed values for the multiplier N (normal range
                 * 60-120).
                 *
                 * Fvco = Fin * N / M
                 */
                fpfd = fin / m;
                n_min = max_t(unsigned int, 60, DIV_ROUND_UP(900000000, fpfd));
                n_max = min_t(unsigned int, 120, 1800000000 / fpfd);

                for (n = n_min; n < n_max; ++n) {
                        unsigned long fvco;
                        unsigned int e_min;
                        unsigned int e;

                        /*
                         * The output frequency is limited to 1039.5 MHz,
                         * limiting again the allowed values for the
                         * post-divider E (normal value 1, 2 or 4).
                         *
                         * Fout = Fvco / E
                         */
                        fvco = fpfd * n;
                        e_min = fvco > 1039500000 ? 1 : 0;

                        for (e = e_min; e < 3; ++e) {
                                unsigned long fout;
                                unsigned long diff;
                                unsigned int div;

                                /*
                                 * Finally we have a programable divider after
                                 * the PLL, followed by a an optional fixed /7
                                 * divider.
                                 */
                                fout = fvco / (1 << e) / div7;
                                div = max(1UL, DIV_ROUND_CLOSEST(fout, target));
                                diff = abs(fout / div - target);

                                if (diff < pll->diff) {
                                        pll->diff = diff;
                                        pll->pll_m = m;
                                        pll->pll_n = n;
                                        pll->pll_e = e;
                                        pll->div = div;
                                        pll->clksel = clksel;

                                        if (diff == 0)
                                                goto done;
                                }
                        }
                }
        }

done:
        output = fin * pll->pll_n / pll->pll_m / (1 << pll->pll_e)
               / div7 / pll->div;
        error = (long)(output - target) * 10000 / (long)target;

        dev_dbg(lvds->dev,
                "%pC %lu Hz -> Fout %lu Hz (target %lu Hz, error %d.%02u%%), PLL M/N/E/DIV %u/%u/%u/%u\n",
                clk, fin, output, target, error / 100,
                error < 0 ? -error % 100 : error % 100,
                pll->pll_m, pll->pll_n, pll->pll_e, pll->div);
}

static void __rcar_lvds_pll_setup_d3_e3(struct rcar_lvds *lvds,
                                        unsigned int freq, bool dot_clock_only)
{
        struct pll_info pll = { .diff = (unsigned long)-1 };
        u32 lvdpllcr;

        rcar_lvds_d3_e3_pll_calc(lvds, lvds->clocks.dotclkin[0], freq, &pll,
                                 LVDPLLCR_CKSEL_DU_DOTCLKIN(0), dot_clock_only);
        rcar_lvds_d3_e3_pll_calc(lvds, lvds->clocks.dotclkin[1], freq, &pll,
                                 LVDPLLCR_CKSEL_DU_DOTCLKIN(1), dot_clock_only);
        rcar_lvds_d3_e3_pll_calc(lvds, lvds->clocks.extal, freq, &pll,
                                 LVDPLLCR_CKSEL_EXTAL, dot_clock_only);

        lvdpllcr = LVDPLLCR_PLLON | pll.clksel | LVDPLLCR_CLKOUT
                 | LVDPLLCR_PLLN(pll.pll_n - 1) | LVDPLLCR_PLLM(pll.pll_m - 1);

        if (pll.pll_e > 0)
                lvdpllcr |= LVDPLLCR_STP_CLKOUTE | LVDPLLCR_OUTCLKSEL
                         |  LVDPLLCR_PLLE(pll.pll_e - 1);

        if (dot_clock_only)
                lvdpllcr |= LVDPLLCR_OCKSEL;

        rcar_lvds_write(lvds, LVDPLLCR, lvdpllcr);

        if (pll.div > 1)
                /*
                 * The DIVRESET bit is a misnomer, setting it to 1 deasserts the
                 * divisor reset.
                 */
                rcar_lvds_write(lvds, LVDDIV, LVDDIV_DIVSEL |
                                LVDDIV_DIVRESET | LVDDIV_DIV(pll.div - 1));
        else
                rcar_lvds_write(lvds, LVDDIV, 0);
}

static void rcar_lvds_pll_setup_d3_e3(struct rcar_lvds *lvds, unsigned int freq)
{
        __rcar_lvds_pll_setup_d3_e3(lvds, freq, false);
}

/* -----------------------------------------------------------------------------
 * Clock - D3/E3 only
 */

int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
        int ret;

        if (WARN_ON(!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)))
                return -ENODEV;

        dev_dbg(lvds->dev, "enabling LVDS PLL, freq=%luHz\n", freq);

        ret = clk_prepare_enable(lvds->clocks.mod);
        if (ret < 0)
                return ret;

        __rcar_lvds_pll_setup_d3_e3(lvds, freq, true);

        return 0;
}
EXPORT_SYMBOL_GPL(rcar_lvds_clk_enable);

void rcar_lvds_clk_disable(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);

        if (WARN_ON(!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)))
                return;

        dev_dbg(lvds->dev, "disabling LVDS PLL\n");

        rcar_lvds_write(lvds, LVDPLLCR, 0);

        clk_disable_unprepare(lvds->clocks.mod);
}
EXPORT_SYMBOL_GPL(rcar_lvds_clk_disable);

/* -----------------------------------------------------------------------------
 * Bridge
 */

static void rcar_lvds_enable(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
        const struct drm_display_mode *mode = &lvds->display_mode;
        u32 lvdhcr;
        u32 lvdcr0;
        int ret;

        ret = clk_prepare_enable(lvds->clocks.mod);
        if (ret < 0)
                return;

        /* Enable the companion LVDS encoder in dual-link mode. */
        if (lvds->dual_link && lvds->companion)
                lvds->companion->funcs->enable(lvds->companion);

        /*
         * Hardcode the channels and control signals routing for now.
         *
         * HSYNC -> CTRL0
         * VSYNC -> CTRL1
         * DISP  -> CTRL2
         * 0     -> CTRL3
         */
        rcar_lvds_write(lvds, LVDCTRCR, LVDCTRCR_CTR3SEL_ZERO |
                        LVDCTRCR_CTR2SEL_DISP | LVDCTRCR_CTR1SEL_VSYNC |
                        LVDCTRCR_CTR0SEL_HSYNC);

        if (lvds->info->quirks & RCAR_LVDS_QUIRK_LANES)
                lvdhcr = LVDCHCR_CHSEL_CH(0, 0) | LVDCHCR_CHSEL_CH(1, 3)
                       | LVDCHCR_CHSEL_CH(2, 2) | LVDCHCR_CHSEL_CH(3, 1);
        else
                lvdhcr = LVDCHCR_CHSEL_CH(0, 0) | LVDCHCR_CHSEL_CH(1, 1)
                       | LVDCHCR_CHSEL_CH(2, 2) | LVDCHCR_CHSEL_CH(3, 3);

        rcar_lvds_write(lvds, LVDCHCR, lvdhcr);

        if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
                /*
                 * Configure vertical stripe based on the mode of operation of
                 * the connected device.
                 */
                rcar_lvds_write(lvds, LVDSTRIPE,
                                lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
        }

        /*
         * PLL clock configuration on all instances but the companion in
         * dual-link mode.
         */
        if (!lvds->dual_link || lvds->companion)
                lvds->info->pll_setup(lvds, mode->clock * 1000);

        /* Set the LVDS mode and select the input. */
        lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;

        if (lvds->bridge.encoder) {
                /*
                 * FIXME: We should really retrieve the CRTC through the state,
                 * but how do we get a state pointer?
                 */
                if (drm_crtc_index(lvds->bridge.encoder->crtc) == 2)
                        lvdcr0 |= LVDCR0_DUSEL;
        }

        rcar_lvds_write(lvds, LVDCR0, lvdcr0);

        /* Turn all the channels on. */
        rcar_lvds_write(lvds, LVDCR1,
                        LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
                        LVDCR1_CHSTBY(1) | LVDCR1_CHSTBY(0) | LVDCR1_CLKSTBY);

        if (lvds->info->gen < 3) {
                /* Enable LVDS operation and turn the bias circuitry on. */
                lvdcr0 |= LVDCR0_BEN | LVDCR0_LVEN;
                rcar_lvds_write(lvds, LVDCR0, lvdcr0);
        }

        if (!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)) {
                /*
                 * Turn the PLL on (simple PLL only, extended PLL is fully
                 * controlled through LVDPLLCR).
                 */
                lvdcr0 |= LVDCR0_PLLON;
                rcar_lvds_write(lvds, LVDCR0, lvdcr0);
        }

        if (lvds->info->quirks & RCAR_LVDS_QUIRK_PWD) {
                /* Set LVDS normal mode. */
                lvdcr0 |= LVDCR0_PWD;
                rcar_lvds_write(lvds, LVDCR0, lvdcr0);
        }

        if (lvds->info->quirks & RCAR_LVDS_QUIRK_GEN3_LVEN) {
                /*
                 * Turn on the LVDS PHY. On D3, the LVEN and LVRES bit must be
                 * set at the same time, so don't write the register yet.
                 */
                lvdcr0 |= LVDCR0_LVEN;
                if (!(lvds->info->quirks & RCAR_LVDS_QUIRK_PWD))
                        rcar_lvds_write(lvds, LVDCR0, lvdcr0);
        }

        if (!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)) {
                /* Wait for the PLL startup delay (simple PLL only). */
                usleep_range(100, 150);
        }

        /* Turn the output on. */
        lvdcr0 |= LVDCR0_LVRES;
        rcar_lvds_write(lvds, LVDCR0, lvdcr0);

        if (lvds->panel) {
                drm_panel_prepare(lvds->panel);
                drm_panel_enable(lvds->panel);
        }
}

static void rcar_lvds_disable(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);

        if (lvds->panel) {
                drm_panel_disable(lvds->panel);
                drm_panel_unprepare(lvds->panel);
        }

        rcar_lvds_write(lvds, LVDCR0, 0);
        rcar_lvds_write(lvds, LVDCR1, 0);
        rcar_lvds_write(lvds, LVDPLLCR, 0);

        /* Disable the companion LVDS encoder in dual-link mode. */
        if (lvds->dual_link && lvds->companion)
                lvds->companion->funcs->disable(lvds->companion);

        clk_disable_unprepare(lvds->clocks.mod);
}

static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
                                 const struct drm_display_mode *mode,
                                 struct drm_display_mode *adjusted_mode)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
        int min_freq;

        /*
         * The internal LVDS encoder has a restricted clock frequency operating
         * range, from 5MHz to 148.5MHz on D3 and E3, and from 31MHz to
         * 148.5MHz on all other platforms. Clamp the clock accordingly.
         */
        min_freq = lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL ? 5000 : 31000;
        adjusted_mode->clock = clamp(adjusted_mode->clock, min_freq, 148500);

        return true;
}

static void rcar_lvds_get_lvds_mode(struct rcar_lvds *lvds)
{
        struct drm_display_info *info = &lvds->connector.display_info;
        enum rcar_lvds_mode mode;

        /*
         * There is no API yet to retrieve LVDS mode from a bridge, only panels
         * are supported.
         */
        if (!lvds->panel)
                return;

        if (!info->num_bus_formats || !info->bus_formats) {
                dev_err(lvds->dev, "no LVDS bus format reported\n");
                return;
        }

        switch (info->bus_formats[0]) {
        case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
        case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
                mode = RCAR_LVDS_MODE_JEIDA;
                break;
        case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
                mode = RCAR_LVDS_MODE_VESA;
                break;
        default:
                dev_err(lvds->dev, "unsupported LVDS bus format 0x%04x\n",
                        info->bus_formats[0]);
                return;
        }

        if (info->bus_flags & DRM_BUS_FLAG_DATA_LSB_TO_MSB)
                mode |= RCAR_LVDS_MODE_MIRROR;

        lvds->mode = mode;
}

static void rcar_lvds_mode_set(struct drm_bridge *bridge,
                               const struct drm_display_mode *mode,
                               const struct drm_display_mode *adjusted_mode)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);

        lvds->display_mode = *adjusted_mode;

        rcar_lvds_get_lvds_mode(lvds);
}

static int rcar_lvds_attach(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
        struct drm_connector *connector = &lvds->connector;
        struct drm_encoder *encoder = bridge->encoder;
        int ret;

        /* If we have a next bridge just attach it. */
        if (lvds->next_bridge)
                return drm_bridge_attach(bridge->encoder, lvds->next_bridge,
                                         bridge);

        /* Otherwise if we have a panel, create a connector. */
        if (!lvds->panel)
                return 0;

        ret = drm_connector_init(bridge->dev, connector, &rcar_lvds_conn_funcs,
                                 DRM_MODE_CONNECTOR_LVDS);
        if (ret < 0)
                return ret;

        drm_connector_helper_add(connector, &rcar_lvds_conn_helper_funcs);

        ret = drm_connector_attach_encoder(connector, encoder);
        if (ret < 0)
                return ret;

        return drm_panel_attach(lvds->panel, connector);
}

static void rcar_lvds_detach(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);

        if (lvds->panel)
                drm_panel_detach(lvds->panel);
}

static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
        .attach = rcar_lvds_attach,
        .detach = rcar_lvds_detach,
        .enable = rcar_lvds_enable,
        .disable = rcar_lvds_disable,
        .mode_fixup = rcar_lvds_mode_fixup,
        .mode_set = rcar_lvds_mode_set,
};

bool rcar_lvds_dual_link(struct drm_bridge *bridge)
{
        struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);

        return lvds->dual_link;
}
EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);

/* -----------------------------------------------------------------------------
 * Probe & Remove
 */

static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
{
        const struct of_device_id *match;
        struct device_node *companion;
        struct device *dev = lvds->dev;
        int ret = 0;

        /* Locate the companion LVDS encoder for dual-link operation, if any. */
        companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
        if (!companion)
                return 0;

        /*
         * Sanity check: the companion encoder must have the same compatible
         * string.
         */
        match = of_match_device(dev->driver->of_match_table, dev);
        if (!of_device_is_compatible(companion, match->compatible)) {
                dev_err(dev, "Companion LVDS encoder is invalid\n");
                ret = -ENXIO;
                goto done;
        }

        lvds->companion = of_drm_find_bridge(companion);
        if (!lvds->companion) {
                ret = -EPROBE_DEFER;
                goto done;
        }

        dev_dbg(dev, "Found companion encoder %pOF\n", companion);

done:
        of_node_put(companion);

        return ret;
}

static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
{
        struct device_node *local_output = NULL;
        struct device_node *remote_input = NULL;
        struct device_node *remote = NULL;
        struct device_node *node;
        bool is_bridge = false;
        int ret = 0;

        local_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, 0);
        if (!local_output) {
                dev_dbg(lvds->dev, "unconnected port@1\n");
                ret = -ENODEV;
                goto done;
        }

        /*
         * Locate the connected entity and infer its type from the number of
         * endpoints.
         */
        remote = of_graph_get_remote_port_parent(local_output);
        if (!remote) {
                dev_dbg(lvds->dev, "unconnected endpoint %pOF\n", local_output);
                ret = -ENODEV;
                goto done;
        }

        if (!of_device_is_available(remote)) {
                dev_dbg(lvds->dev, "connected entity %pOF is disabled\n",
                        remote);
                ret = -ENODEV;
                goto done;
        }

        remote_input = of_graph_get_remote_endpoint(local_output);

        for_each_endpoint_of_node(remote, node) {
                if (node != remote_input) {
                        /*
                         * We've found one endpoint other than the input, this
                         * must be a bridge.
                         */
                        is_bridge = true;
                        of_node_put(node);
                        break;
                }
        }

        if (is_bridge) {
                lvds->next_bridge = of_drm_find_bridge(remote);
                if (!lvds->next_bridge) {
                        ret = -EPROBE_DEFER;
                        goto done;
                }

                if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
                        lvds->dual_link = lvds->next_bridge->timings
                                        ? lvds->next_bridge->timings->dual_link
                                        : false;
        } else {
                lvds->panel = of_drm_find_panel(remote);
                if (IS_ERR(lvds->panel)) {
                        ret = PTR_ERR(lvds->panel);
                        goto done;
                }
        }

        if (lvds->dual_link)
                ret = rcar_lvds_parse_dt_companion(lvds);

done:
        of_node_put(local_output);
        of_node_put(remote_input);
        of_node_put(remote);

        /*
         * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
         * used for the DPAD output even when the LVDS output is not connected.
         * Don't fail probe in that case as the DU will need the bridge to
         * control the clock.
         */
        if (lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)
                return ret == -ENODEV ? 0 : ret;

        return ret;
}

static struct clk *rcar_lvds_get_clock(struct rcar_lvds *lvds, const char *name,
                                       bool optional)
{
        struct clk *clk;

        clk = devm_clk_get(lvds->dev, name);
        if (!IS_ERR(clk))
                return clk;

        if (PTR_ERR(clk) == -ENOENT && optional)
                return NULL;

        if (PTR_ERR(clk) != -EPROBE_DEFER)
                dev_err(lvds->dev, "failed to get %s clock\n",
                        name ? name : "module");

        return clk;
}

static int rcar_lvds_get_clocks(struct rcar_lvds *lvds)
{
        lvds->clocks.mod = rcar_lvds_get_clock(lvds, NULL, false);
        if (IS_ERR(lvds->clocks.mod))
                return PTR_ERR(lvds->clocks.mod);

        /*
         * LVDS encoders without an extended PLL have no external clock inputs.
         */
        if (!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL))
                return 0;

        lvds->clocks.extal = rcar_lvds_get_clock(lvds, "extal", true);
        if (IS_ERR(lvds->clocks.extal))
                return PTR_ERR(lvds->clocks.extal);

        lvds->clocks.dotclkin[0] = rcar_lvds_get_clock(lvds, "dclkin.0", true);
        if (IS_ERR(lvds->clocks.dotclkin[0]))
                return PTR_ERR(lvds->clocks.dotclkin[0]);

        lvds->clocks.dotclkin[1] = rcar_lvds_get_clock(lvds, "dclkin.1", true);
        if (IS_ERR(lvds->clocks.dotclkin[1]))
                return PTR_ERR(lvds->clocks.dotclkin[1]);

        /* At least one input to the PLL must be available. */
        if (!lvds->clocks.extal && !lvds->clocks.dotclkin[0] &&
            !lvds->clocks.dotclkin[1]) {
                dev_err(lvds->dev,
                        "no input clock (extal, dclkin.0 or dclkin.1)\n");
                return -EINVAL;
        }

        return 0;
}

static int rcar_lvds_probe(struct platform_device *pdev)
{
        struct rcar_lvds *lvds;
        struct resource *mem;
        int ret;

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

        platform_set_drvdata(pdev, lvds);

        lvds->dev = &pdev->dev;
        lvds->info = of_device_get_match_data(&pdev->dev);

        ret = rcar_lvds_parse_dt(lvds);
        if (ret < 0)
                return ret;

        lvds->bridge.driver_private = lvds;
        lvds->bridge.funcs = &rcar_lvds_bridge_ops;
        lvds->bridge.of_node = pdev->dev.of_node;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        lvds->mmio = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(lvds->mmio))
                return PTR_ERR(lvds->mmio);

        ret = rcar_lvds_get_clocks(lvds);
        if (ret < 0)
                return ret;

        drm_bridge_add(&lvds->bridge);

        return 0;
}

static int rcar_lvds_remove(struct platform_device *pdev)
{
        struct rcar_lvds *lvds = platform_get_drvdata(pdev);

        drm_bridge_remove(&lvds->bridge);

        return 0;
}

static const struct rcar_lvds_device_info rcar_lvds_gen2_info = {
        .gen = 2,
        .pll_setup = rcar_lvds_pll_setup_gen2,
};

static const struct rcar_lvds_device_info rcar_lvds_r8a7790_info = {
        .gen = 2,
        .quirks = RCAR_LVDS_QUIRK_LANES,
        .pll_setup = rcar_lvds_pll_setup_gen2,
};

static const struct rcar_lvds_device_info rcar_lvds_gen3_info = {
        .gen = 3,
        .quirks = RCAR_LVDS_QUIRK_PWD,
        .pll_setup = rcar_lvds_pll_setup_gen3,
};

static const struct rcar_lvds_device_info rcar_lvds_r8a77970_info = {
        .gen = 3,
        .quirks = RCAR_LVDS_QUIRK_PWD | RCAR_LVDS_QUIRK_GEN3_LVEN,
        .pll_setup = rcar_lvds_pll_setup_gen2,
};

static const struct rcar_lvds_device_info rcar_lvds_r8a77990_info = {
        .gen = 3,
        .quirks = RCAR_LVDS_QUIRK_GEN3_LVEN | RCAR_LVDS_QUIRK_EXT_PLL
                | RCAR_LVDS_QUIRK_DUAL_LINK,
        .pll_setup = rcar_lvds_pll_setup_d3_e3,
};

static const struct rcar_lvds_device_info rcar_lvds_r8a77995_info = {
        .gen = 3,
        .quirks = RCAR_LVDS_QUIRK_GEN3_LVEN | RCAR_LVDS_QUIRK_PWD
                | RCAR_LVDS_QUIRK_EXT_PLL | RCAR_LVDS_QUIRK_DUAL_LINK,
        .pll_setup = rcar_lvds_pll_setup_d3_e3,
};

static const struct of_device_id rcar_lvds_of_table[] = {
        { .compatible = "renesas,r8a7743-lvds", .data = &rcar_lvds_gen2_info },
        { .compatible = "renesas,r8a7744-lvds", .data = &rcar_lvds_gen2_info },
        { .compatible = "renesas,r8a774a1-lvds", .data = &rcar_lvds_gen3_info },
        { .compatible = "renesas,r8a774c0-lvds", .data = &rcar_lvds_r8a77990_info },
        { .compatible = "renesas,r8a7790-lvds", .data = &rcar_lvds_r8a7790_info },
        { .compatible = "renesas,r8a7791-lvds", .data = &rcar_lvds_gen2_info },
        { .compatible = "renesas,r8a7793-lvds", .data = &rcar_lvds_gen2_info },
        { .compatible = "renesas,r8a7795-lvds", .data = &rcar_lvds_gen3_info },
        { .compatible = "renesas,r8a7796-lvds", .data = &rcar_lvds_gen3_info },
        { .compatible = "renesas,r8a77965-lvds", .data = &rcar_lvds_gen3_info },
        { .compatible = "renesas,r8a77970-lvds", .data = &rcar_lvds_r8a77970_info },
        { .compatible = "renesas,r8a77980-lvds", .data = &rcar_lvds_gen3_info },
        { .compatible = "renesas,r8a77990-lvds", .data = &rcar_lvds_r8a77990_info },
        { .compatible = "renesas,r8a77995-lvds", .data = &rcar_lvds_r8a77995_info },
        { }
};

MODULE_DEVICE_TABLE(of, rcar_lvds_of_table);

static struct platform_driver rcar_lvds_platform_driver = {
        .probe          = rcar_lvds_probe,
        .remove         = rcar_lvds_remove,
        .driver         = {
                .name   = "rcar-lvds",
                .of_match_table = rcar_lvds_of_table,
        },
};

module_platform_driver(rcar_lvds_platform_driver);

MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
MODULE_DESCRIPTION("Renesas R-Car LVDS Encoder Driver");
MODULE_LICENSE("GPL");