// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
 * Copyright (C) STMicroelectronics SA 2017
 *
 * Modified by Philippe Cornu <philippe.cornu@st.com>
 * This generic Synopsys DesignWare MIPI DSI host driver is based on the
 * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
 */

#include <linux/clk.h>
#include <linux/component.h>
#include <linux/debugfs.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#include <video/mipi_display.h>

#include <drm/bridge/dw_mipi_dsi.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_crtc.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_modes.h>
#include <drm/drm_of.h>
#include <drm/drm_print.h>

#define HWVER_131                       0x31333100      /* IP version 1.31 */

#define DSI_VERSION                     0x00
#define VERSION                         GENMASK(31, 8)

#define DSI_PWR_UP                      0x04
#define RESET                           0
#define POWERUP                         BIT(0)

#define DSI_CLKMGR_CFG                  0x08
#define TO_CLK_DIVISION(div)            (((div) & 0xff) << 8)
#define TX_ESC_CLK_DIVISION(div)        ((div) & 0xff)

#define DSI_DPI_VCID                    0x0c
#define DPI_VCID(vcid)                  ((vcid) & 0x3)

#define DSI_DPI_COLOR_CODING            0x10
#define LOOSELY18_EN                    BIT(8)
#define DPI_COLOR_CODING_16BIT_1        0x0
#define DPI_COLOR_CODING_16BIT_2        0x1
#define DPI_COLOR_CODING_16BIT_3        0x2
#define DPI_COLOR_CODING_18BIT_1        0x3
#define DPI_COLOR_CODING_18BIT_2        0x4
#define DPI_COLOR_CODING_24BIT          0x5

#define DSI_DPI_CFG_POL                 0x14
#define COLORM_ACTIVE_LOW               BIT(4)
#define SHUTD_ACTIVE_LOW                BIT(3)
#define HSYNC_ACTIVE_LOW                BIT(2)
#define VSYNC_ACTIVE_LOW                BIT(1)
#define DATAEN_ACTIVE_LOW               BIT(0)

#define DSI_DPI_LP_CMD_TIM              0x18
#define OUTVACT_LPCMD_TIME(p)           (((p) & 0xff) << 16)
#define INVACT_LPCMD_TIME(p)            ((p) & 0xff)

#define DSI_DBI_VCID                    0x1c
#define DSI_DBI_CFG                     0x20
#define DSI_DBI_PARTITIONING_EN         0x24
#define DSI_DBI_CMDSIZE                 0x28

#define DSI_PCKHDL_CFG                  0x2c
#define CRC_RX_EN                       BIT(4)
#define ECC_RX_EN                       BIT(3)
#define BTA_EN                          BIT(2)
#define EOTP_RX_EN                      BIT(1)
#define EOTP_TX_EN                      BIT(0)

#define DSI_GEN_VCID                    0x30

#define DSI_MODE_CFG                    0x34
#define ENABLE_VIDEO_MODE               0
#define ENABLE_CMD_MODE                 BIT(0)

#define DSI_VID_MODE_CFG                0x38
#define ENABLE_LOW_POWER                (0x3f << 8)
#define ENABLE_LOW_POWER_MASK           (0x3f << 8)
#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES     0x0
#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS     0x1
#define VID_MODE_TYPE_BURST                     0x2
#define VID_MODE_TYPE_MASK                      0x3
#define VID_MODE_VPG_ENABLE             BIT(16)
#define VID_MODE_VPG_HORIZONTAL         BIT(24)

#define DSI_VID_PKT_SIZE                0x3c
#define VID_PKT_SIZE(p)                 ((p) & 0x3fff)

#define DSI_VID_NUM_CHUNKS              0x40
#define VID_NUM_CHUNKS(c)               ((c) & 0x1fff)

#define DSI_VID_NULL_SIZE               0x44
#define VID_NULL_SIZE(b)                ((b) & 0x1fff)

#define DSI_VID_HSA_TIME                0x48
#define DSI_VID_HBP_TIME                0x4c
#define DSI_VID_HLINE_TIME              0x50
#define DSI_VID_VSA_LINES               0x54
#define DSI_VID_VBP_LINES               0x58
#define DSI_VID_VFP_LINES               0x5c
#define DSI_VID_VACTIVE_LINES           0x60
#define DSI_EDPI_CMD_SIZE               0x64

#define DSI_CMD_MODE_CFG                0x68
#define MAX_RD_PKT_SIZE_LP              BIT(24)
#define DCS_LW_TX_LP                    BIT(19)
#define DCS_SR_0P_TX_LP                 BIT(18)
#define DCS_SW_1P_TX_LP                 BIT(17)
#define DCS_SW_0P_TX_LP                 BIT(16)
#define GEN_LW_TX_LP                    BIT(14)
#define GEN_SR_2P_TX_LP                 BIT(13)
#define GEN_SR_1P_TX_LP                 BIT(12)
#define GEN_SR_0P_TX_LP                 BIT(11)
#define GEN_SW_2P_TX_LP                 BIT(10)
#define GEN_SW_1P_TX_LP                 BIT(9)
#define GEN_SW_0P_TX_LP                 BIT(8)
#define ACK_RQST_EN                     BIT(1)
#define TEAR_FX_EN                      BIT(0)

#define CMD_MODE_ALL_LP                 (MAX_RD_PKT_SIZE_LP | \
                                         DCS_LW_TX_LP | \
                                         DCS_SR_0P_TX_LP | \
                                         DCS_SW_1P_TX_LP | \
                                         DCS_SW_0P_TX_LP | \
                                         GEN_LW_TX_LP | \
                                         GEN_SR_2P_TX_LP | \
                                         GEN_SR_1P_TX_LP | \
                                         GEN_SR_0P_TX_LP | \
                                         GEN_SW_2P_TX_LP | \
                                         GEN_SW_1P_TX_LP | \
                                         GEN_SW_0P_TX_LP)

#define DSI_GEN_HDR                     0x6c
#define DSI_GEN_PLD_DATA                0x70

#define DSI_CMD_PKT_STATUS              0x74
#define GEN_RD_CMD_BUSY                 BIT(6)
#define GEN_PLD_R_FULL                  BIT(5)
#define GEN_PLD_R_EMPTY                 BIT(4)
#define GEN_PLD_W_FULL                  BIT(3)
#define GEN_PLD_W_EMPTY                 BIT(2)
#define GEN_CMD_FULL                    BIT(1)
#define GEN_CMD_EMPTY                   BIT(0)

#define DSI_TO_CNT_CFG                  0x78
#define HSTX_TO_CNT(p)                  (((p) & 0xffff) << 16)
#define LPRX_TO_CNT(p)                  ((p) & 0xffff)

#define DSI_HS_RD_TO_CNT                0x7c
#define DSI_LP_RD_TO_CNT                0x80
#define DSI_HS_WR_TO_CNT                0x84
#define DSI_LP_WR_TO_CNT                0x88
#define DSI_BTA_TO_CNT                  0x8c

#define DSI_LPCLK_CTRL                  0x94
#define AUTO_CLKLANE_CTRL               BIT(1)
#define PHY_TXREQUESTCLKHS              BIT(0)

#define DSI_PHY_TMR_LPCLK_CFG           0x98
#define PHY_CLKHS2LP_TIME(lbcc)         (((lbcc) & 0x3ff) << 16)
#define PHY_CLKLP2HS_TIME(lbcc)         ((lbcc) & 0x3ff)

#define DSI_PHY_TMR_CFG                 0x9c
#define PHY_HS2LP_TIME(lbcc)            (((lbcc) & 0xff) << 24)
#define PHY_LP2HS_TIME(lbcc)            (((lbcc) & 0xff) << 16)
#define MAX_RD_TIME(lbcc)               ((lbcc) & 0x7fff)
#define PHY_HS2LP_TIME_V131(lbcc)       (((lbcc) & 0x3ff) << 16)
#define PHY_LP2HS_TIME_V131(lbcc)       ((lbcc) & 0x3ff)

#define DSI_PHY_RSTZ                    0xa0
#define PHY_DISFORCEPLL                 0
#define PHY_ENFORCEPLL                  BIT(3)
#define PHY_DISABLECLK                  0
#define PHY_ENABLECLK                   BIT(2)
#define PHY_RSTZ                        0
#define PHY_UNRSTZ                      BIT(1)
#define PHY_SHUTDOWNZ                   0
#define PHY_UNSHUTDOWNZ                 BIT(0)

#define DSI_PHY_IF_CFG                  0xa4
#define PHY_STOP_WAIT_TIME(cycle)       (((cycle) & 0xff) << 8)
#define N_LANES(n)                      (((n) - 1) & 0x3)

#define DSI_PHY_ULPS_CTRL               0xa8
#define DSI_PHY_TX_TRIGGERS             0xac

#define DSI_PHY_STATUS                  0xb0
#define PHY_STOP_STATE_CLK_LANE         BIT(2)
#define PHY_LOCK                        BIT(0)

#define DSI_PHY_TST_CTRL0               0xb4
#define PHY_TESTCLK                     BIT(1)
#define PHY_UNTESTCLK                   0
#define PHY_TESTCLR                     BIT(0)
#define PHY_UNTESTCLR                   0

#define DSI_PHY_TST_CTRL1               0xb8
#define PHY_TESTEN                      BIT(16)
#define PHY_UNTESTEN                    0
#define PHY_TESTDOUT(n)                 (((n) & 0xff) << 8)
#define PHY_TESTDIN(n)                  ((n) & 0xff)

#define DSI_INT_ST0                     0xbc
#define DSI_INT_ST1                     0xc0
#define DSI_INT_MSK0                    0xc4
#define DSI_INT_MSK1                    0xc8

#define DSI_PHY_TMR_RD_CFG              0xf4
#define MAX_RD_TIME_V131(lbcc)          ((lbcc) & 0x7fff)

#define PHY_STATUS_TIMEOUT_US           10000
#define CMD_PKT_STATUS_TIMEOUT_US       20000

struct dw_mipi_dsi {
        struct drm_bridge bridge;
        struct mipi_dsi_host dsi_host;
        struct drm_bridge *panel_bridge;
        struct device *dev;
        void __iomem *base;

        struct clk *pclk;

        unsigned int lane_mbps; /* per lane */
        u32 channel;
        u32 lanes;
        u32 format;
        unsigned long mode_flags;

#ifdef CONFIG_DEBUG_FS
        struct dentry *debugfs;

        bool vpg;
        bool vpg_horizontal;
#endif /* CONFIG_DEBUG_FS */

        struct dw_mipi_dsi *master; /* dual-dsi master ptr */
        struct dw_mipi_dsi *slave; /* dual-dsi slave ptr */

        const struct dw_mipi_dsi_plat_data *plat_data;
};

/*
 * Check if either a link to a master or slave is present
 */
static inline bool dw_mipi_is_dual_mode(struct dw_mipi_dsi *dsi)
{
        return dsi->slave || dsi->master;
}

/*
 * The controller should generate 2 frames before
 * preparing the peripheral.
 */
static void dw_mipi_dsi_wait_for_two_frames(const struct drm_display_mode *mode)
{
        int refresh, two_frames;

        refresh = drm_mode_vrefresh(mode);
        two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
        msleep(two_frames);
}

static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
{
        return container_of(host, struct dw_mipi_dsi, dsi_host);
}

static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
{
        return container_of(bridge, struct dw_mipi_dsi, bridge);
}

static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
{
        writel(val, dsi->base + reg);
}

static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
{
        return readl(dsi->base + reg);
}

static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
                                   struct mipi_dsi_device *device)
{
        struct dw_mipi_dsi *dsi = host_to_dsi(host);
        const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
        struct drm_bridge *bridge;
        struct drm_panel *panel;
        int ret;

        if (device->lanes > dsi->plat_data->max_data_lanes) {
                dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
                        device->lanes);
                return -EINVAL;
        }

        dsi->lanes = device->lanes;
        dsi->channel = device->channel;
        dsi->format = device->format;
        dsi->mode_flags = device->mode_flags;

        ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
                                          &panel, &bridge);
        if (ret)
                return ret;

        if (panel) {
                bridge = drm_panel_bridge_add_typed(panel,
                                                    DRM_MODE_CONNECTOR_DSI);
                if (IS_ERR(bridge))
                        return PTR_ERR(bridge);
        }

        dsi->panel_bridge = bridge;

        drm_bridge_add(&dsi->bridge);

        if (pdata->host_ops && pdata->host_ops->attach) {
                ret = pdata->host_ops->attach(pdata->priv_data, device);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
                                   struct mipi_dsi_device *device)
{
        struct dw_mipi_dsi *dsi = host_to_dsi(host);
        const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
        int ret;

        if (pdata->host_ops && pdata->host_ops->detach) {
                ret = pdata->host_ops->detach(pdata->priv_data, device);
                if (ret < 0)
                        return ret;
        }

        drm_of_panel_bridge_remove(host->dev->of_node, 1, 0);

        drm_bridge_remove(&dsi->bridge);

        return 0;
}

static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
                                   const struct mipi_dsi_msg *msg)
{
        bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
        u32 val = 0;

        if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
                val |= ACK_RQST_EN;
        if (lpm)
                val |= CMD_MODE_ALL_LP;

        dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
        dsi_write(dsi, DSI_CMD_MODE_CFG, val);
}

static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
{
        int ret;
        u32 val, mask;

        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
                                 val, !(val & GEN_CMD_FULL), 1000,
                                 CMD_PKT_STATUS_TIMEOUT_US);
        if (ret) {
                dev_err(dsi->dev, "failed to get available command FIFO\n");
                return ret;
        }

        dsi_write(dsi, DSI_GEN_HDR, hdr_val);

        mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
                                 val, (val & mask) == mask,
                                 1000, CMD_PKT_STATUS_TIMEOUT_US);
        if (ret) {
                dev_err(dsi->dev, "failed to write command FIFO\n");
                return ret;
        }

        return 0;
}

static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
                             const struct mipi_dsi_packet *packet)
{
        const u8 *tx_buf = packet->payload;
        int len = packet->payload_length, pld_data_bytes = sizeof(u32), ret;
        __le32 word;
        u32 val;

        while (len) {
                if (len < pld_data_bytes) {
                        word = 0;
                        memcpy(&word, tx_buf, len);
                        dsi_write(dsi, DSI_GEN_PLD_DATA, le32_to_cpu(word));
                        len = 0;
                } else {
                        memcpy(&word, tx_buf, pld_data_bytes);
                        dsi_write(dsi, DSI_GEN_PLD_DATA, le32_to_cpu(word));
                        tx_buf += pld_data_bytes;
                        len -= pld_data_bytes;
                }

                ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
                                         val, !(val & GEN_PLD_W_FULL), 1000,
                                         CMD_PKT_STATUS_TIMEOUT_US);
                if (ret) {
                        dev_err(dsi->dev,
                                "failed to get available write payload FIFO\n");
                        return ret;
                }
        }

        word = 0;
        memcpy(&word, packet->header, sizeof(packet->header));
        return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
}

static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
                            const struct mipi_dsi_msg *msg)
{
        int i, j, ret, len = msg->rx_len;
        u8 *buf = msg->rx_buf;
        u32 val;

        /* Wait end of the read operation */
        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
                                 val, !(val & GEN_RD_CMD_BUSY),
                                 1000, CMD_PKT_STATUS_TIMEOUT_US);
        if (ret) {
                dev_err(dsi->dev, "Timeout during read operation\n");
                return ret;
        }

        for (i = 0; i < len; i += 4) {
                /* Read fifo must not be empty before all bytes are read */
                ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
                                         val, !(val & GEN_PLD_R_EMPTY),
                                         1000, CMD_PKT_STATUS_TIMEOUT_US);
                if (ret) {
                        dev_err(dsi->dev, "Read payload FIFO is empty\n");
                        return ret;
                }

                val = dsi_read(dsi, DSI_GEN_PLD_DATA);
                for (j = 0; j < 4 && j + i < len; j++)
                        buf[i + j] = val >> (8 * j);
        }

        return ret;
}

static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
                                         const struct mipi_dsi_msg *msg)
{
        struct dw_mipi_dsi *dsi = host_to_dsi(host);
        struct mipi_dsi_packet packet;
        int ret, nb_bytes;

        ret = mipi_dsi_create_packet(&packet, msg);
        if (ret) {
                dev_err(dsi->dev, "failed to create packet: %d\n", ret);
                return ret;
        }

        dw_mipi_message_config(dsi, msg);
        if (dsi->slave)
                dw_mipi_message_config(dsi->slave, msg);

        ret = dw_mipi_dsi_write(dsi, &packet);
        if (ret)
                return ret;
        if (dsi->slave) {
                ret = dw_mipi_dsi_write(dsi->slave, &packet);
                if (ret)
                        return ret;
        }

        if (msg->rx_buf && msg->rx_len) {
                ret = dw_mipi_dsi_read(dsi, msg);
                if (ret)
                        return ret;
                nb_bytes = msg->rx_len;
        } else {
                nb_bytes = packet.size;
        }

        return nb_bytes;
}

static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
        .attach = dw_mipi_dsi_host_attach,
        .detach = dw_mipi_dsi_host_detach,
        .transfer = dw_mipi_dsi_host_transfer,
};

static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
{
        u32 val;

        /*
         * TODO dw drv improvements
         * enabling low power is panel-dependent, we should use the
         * panel configuration here...
         */
        val = ENABLE_LOW_POWER;

        if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
                val |= VID_MODE_TYPE_BURST;
        else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
                val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
        else
                val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;

#ifdef CONFIG_DEBUG_FS
        if (dsi->vpg) {
                val |= VID_MODE_VPG_ENABLE;
                val |= dsi->vpg_horizontal ? VID_MODE_VPG_HORIZONTAL : 0;
        }
#endif /* CONFIG_DEBUG_FS */

        dsi_write(dsi, DSI_VID_MODE_CFG, val);
}

static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
                                 unsigned long mode_flags)
{
        dsi_write(dsi, DSI_PWR_UP, RESET);

        if (mode_flags & MIPI_DSI_MODE_VIDEO) {
                dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
                dw_mipi_dsi_video_mode_config(dsi);
                dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
        } else {
                dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
        }

        dsi_write(dsi, DSI_PWR_UP, POWERUP);
}

static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
{
        dsi_write(dsi, DSI_PWR_UP, RESET);
        dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
}

static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
{
        /*
         * The maximum permitted escape clock is 20MHz and it is derived from
         * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
         *
         *     (lane_mbps >> 3) / esc_clk_division < 20
         * which is:
         *     (lane_mbps >> 3) / 20 > esc_clk_division
         */
        u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;

        dsi_write(dsi, DSI_PWR_UP, RESET);

        /*
         * TODO dw drv improvements
         * timeout clock division should be computed with the
         * high speed transmission counter timeout and byte lane...
         */
        dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVISION(10) |
                  TX_ESC_CLK_DIVISION(esc_clk_division));
}

static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
                                   const struct drm_display_mode *mode)
{
        u32 val = 0, color = 0;

        switch (dsi->format) {
        case MIPI_DSI_FMT_RGB888:
                color = DPI_COLOR_CODING_24BIT;
                break;
        case MIPI_DSI_FMT_RGB666:
                color = DPI_COLOR_CODING_18BIT_2 | LOOSELY18_EN;
                break;
        case MIPI_DSI_FMT_RGB666_PACKED:
                color = DPI_COLOR_CODING_18BIT_1;
                break;
        case MIPI_DSI_FMT_RGB565:
                color = DPI_COLOR_CODING_16BIT_1;
                break;
        }

        if (mode->flags & DRM_MODE_FLAG_NVSYNC)
                val |= VSYNC_ACTIVE_LOW;
        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
                val |= HSYNC_ACTIVE_LOW;

        dsi_write(dsi, DSI_DPI_VCID, DPI_VCID(dsi->channel));
        dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
        dsi_write(dsi, DSI_DPI_CFG_POL, val);
        /*
         * TODO dw drv improvements
         * largest packet sizes during hfp or during vsa/vpb/vfp
         * should be computed according to byte lane, lane number and only
         * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
         */
        dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
                  | INVACT_LPCMD_TIME(4));
}

static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
{
        dsi_write(dsi, DSI_PCKHDL_CFG, CRC_RX_EN | ECC_RX_EN | BTA_EN);
}

static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
                                            const struct drm_display_mode *mode)
{
        /*
         * TODO dw drv improvements
         * only burst mode is supported here. For non-burst video modes,
         * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
         * DSI_VNPCR.NPSIZE... especially because this driver supports
         * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
         */

        dsi_write(dsi, DSI_VID_PKT_SIZE,
                       dw_mipi_is_dual_mode(dsi) ?
                                VID_PKT_SIZE(mode->hdisplay / 2) :
                                VID_PKT_SIZE(mode->hdisplay));
}

static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
{
        /*
         * TODO dw drv improvements
         * compute high speed transmission counter timeout according
         * to the timeout clock division (TO_CLK_DIVISION) and byte lane...
         */
        dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
        /*
         * TODO dw drv improvements
         * the Bus-Turn-Around Timeout Counter should be computed
         * according to byte lane...
         */
        dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
        dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
}

/* Get lane byte clock cycles. */
static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
                                           const struct drm_display_mode *mode,
                                           u32 hcomponent)
{
        u32 frac, lbcc;

        lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;

        frac = lbcc % mode->clock;
        lbcc = lbcc / mode->clock;
        if (frac)
                lbcc++;

        return lbcc;
}

static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
                                          const struct drm_display_mode *mode)
{
        u32 htotal, hsa, hbp, lbcc;

        htotal = mode->htotal;
        hsa = mode->hsync_end - mode->hsync_start;
        hbp = mode->htotal - mode->hsync_end;

        /*
         * TODO dw drv improvements
         * computations below may be improved...
         */
        lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
        dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);

        lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
        dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);

        lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
        dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
}

static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
                                        const struct drm_display_mode *mode)
{
        u32 vactive, vsa, vfp, vbp;

        vactive = mode->vdisplay;
        vsa = mode->vsync_end - mode->vsync_start;
        vfp = mode->vsync_start - mode->vdisplay;
        vbp = mode->vtotal - mode->vsync_end;

        dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
        dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
        dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
        dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
}

static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
{
        const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
        struct dw_mipi_dsi_dphy_timing timing;
        u32 hw_version;
        int ret;

        ret = phy_ops->get_timing(dsi->plat_data->priv_data,
                                  dsi->lane_mbps, &timing);
        if (ret)
                DRM_DEV_ERROR(dsi->dev, "Retrieving phy timings failed\n");

        /*
         * TODO dw drv improvements
         * data & clock lane timers should be computed according to panel
         * blankings and to the automatic clock lane control mode...
         * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
         * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
         */

        hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;

        if (hw_version >= HWVER_131) {
                dsi_write(dsi, DSI_PHY_TMR_CFG,
                          PHY_HS2LP_TIME_V131(timing.data_hs2lp) |
                          PHY_LP2HS_TIME_V131(timing.data_lp2hs));
                dsi_write(dsi, DSI_PHY_TMR_RD_CFG, MAX_RD_TIME_V131(10000));
        } else {
                dsi_write(dsi, DSI_PHY_TMR_CFG,
                          PHY_HS2LP_TIME(timing.data_hs2lp) |
                          PHY_LP2HS_TIME(timing.data_lp2hs) |
                          MAX_RD_TIME(10000));
        }

        dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG,
                  PHY_CLKHS2LP_TIME(timing.clk_hs2lp) |
                  PHY_CLKLP2HS_TIME(timing.clk_lp2hs));
}

static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
{
        /*
         * TODO dw drv improvements
         * stop wait time should be the maximum between host dsi
         * and panel stop wait times
         */
        dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
                  N_LANES(dsi->lanes));
}

static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
{
        /* Clear PHY state */
        dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
                  | PHY_RSTZ | PHY_SHUTDOWNZ);
        dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
        dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
        dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
}

static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
{
        u32 val;
        int ret;

        dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
                  PHY_UNRSTZ | PHY_UNSHUTDOWNZ);

        ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS, val,
                                 val & PHY_LOCK, 1000, PHY_STATUS_TIMEOUT_US);
        if (ret)
                DRM_DEBUG_DRIVER("failed to wait phy lock state\n");

        ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
                                 val, val & PHY_STOP_STATE_CLK_LANE, 1000,
                                 PHY_STATUS_TIMEOUT_US);
        if (ret)
                DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
}

static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
{
        dsi_read(dsi, DSI_INT_ST0);
        dsi_read(dsi, DSI_INT_ST1);
        dsi_write(dsi, DSI_INT_MSK0, 0);
        dsi_write(dsi, DSI_INT_MSK1, 0);
}

static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
{
        struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
        const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;

        /*
         * Switch to command mode before panel-bridge post_disable &
         * panel unprepare.
         * Note: panel-bridge disable & panel disable has been called
         * before by the drm framework.
         */
        dw_mipi_dsi_set_mode(dsi, 0);

        /*
         * TODO Only way found to call panel-bridge post_disable &
         * panel unprepare before the dsi "final" disable...
         * This needs to be fixed in the drm_bridge framework and the API
         * needs to be updated to manage our own call chains...
         */
        if (dsi->panel_bridge->funcs->post_disable)
                dsi->panel_bridge->funcs->post_disable(dsi->panel_bridge);

        if (phy_ops->power_off)
                phy_ops->power_off(dsi->plat_data->priv_data);

        if (dsi->slave) {
                dw_mipi_dsi_disable(dsi->slave);
                clk_disable_unprepare(dsi->slave->pclk);
                pm_runtime_put(dsi->slave->dev);
        }
        dw_mipi_dsi_disable(dsi);

        clk_disable_unprepare(dsi->pclk);
        pm_runtime_put(dsi->dev);
}

static unsigned int dw_mipi_dsi_get_lanes(struct dw_mipi_dsi *dsi)
{
        /* this instance is the slave, so add the master's lanes */
        if (dsi->master)
                return dsi->master->lanes + dsi->lanes;

        /* this instance is the master, so add the slave's lanes */
        if (dsi->slave)
                return dsi->lanes + dsi->slave->lanes;

        /* single-dsi, so no other instance to consider */
        return dsi->lanes;
}

static void dw_mipi_dsi_mode_set(struct dw_mipi_dsi *dsi,
                                 const struct drm_display_mode *adjusted_mode)
{
        const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
        void *priv_data = dsi->plat_data->priv_data;
        int ret;
        u32 lanes = dw_mipi_dsi_get_lanes(dsi);

        clk_prepare_enable(dsi->pclk);

        ret = phy_ops->get_lane_mbps(priv_data, adjusted_mode, dsi->mode_flags,
                                     lanes, dsi->format, &dsi->lane_mbps);
        if (ret)
                DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");

        pm_runtime_get_sync(dsi->dev);
        dw_mipi_dsi_init(dsi);
        dw_mipi_dsi_dpi_config(dsi, adjusted_mode);
        dw_mipi_dsi_packet_handler_config(dsi);
        dw_mipi_dsi_video_mode_config(dsi);
        dw_mipi_dsi_video_packet_config(dsi, adjusted_mode);
        dw_mipi_dsi_command_mode_config(dsi);
        dw_mipi_dsi_line_timer_config(dsi, adjusted_mode);
        dw_mipi_dsi_vertical_timing_config(dsi, adjusted_mode);

        dw_mipi_dsi_dphy_init(dsi);
        dw_mipi_dsi_dphy_timing_config(dsi);
        dw_mipi_dsi_dphy_interface_config(dsi);

        dw_mipi_dsi_clear_err(dsi);

        ret = phy_ops->init(priv_data);
        if (ret)
                DRM_DEBUG_DRIVER("Phy init() failed\n");

        dw_mipi_dsi_dphy_enable(dsi);

        dw_mipi_dsi_wait_for_two_frames(adjusted_mode);

        /* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
        dw_mipi_dsi_set_mode(dsi, 0);

        if (phy_ops->power_on)
                phy_ops->power_on(dsi->plat_data->priv_data);
}

static void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
                                        const struct drm_display_mode *mode,
                                        const struct drm_display_mode *adjusted_mode)
{
        struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);

        dw_mipi_dsi_mode_set(dsi, adjusted_mode);
        if (dsi->slave)
                dw_mipi_dsi_mode_set(dsi->slave, adjusted_mode);
}

static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
{
        struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);

        /* Switch to video mode for panel-bridge enable & panel enable */
        dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
        if (dsi->slave)
                dw_mipi_dsi_set_mode(dsi->slave, MIPI_DSI_MODE_VIDEO);
}

static enum drm_mode_status
dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
                              const struct drm_display_info *info,
                              const struct drm_display_mode *mode)
{
        struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
        const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
        enum drm_mode_status mode_status = MODE_OK;

        if (pdata->mode_valid)
                mode_status = pdata->mode_valid(pdata->priv_data, mode);

        return mode_status;
}

static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge,
                                     enum drm_bridge_attach_flags flags)
{
        struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);

        if (!bridge->encoder) {
                DRM_ERROR("Parent encoder object not found\n");
                return -ENODEV;
        }

        /* Set the encoder type as caller does not know it */
        bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;

        /* Attach the panel-bridge to the dsi bridge */
        return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge,
                                 flags);
}

static const struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
        .mode_set     = dw_mipi_dsi_bridge_mode_set,
        .enable       = dw_mipi_dsi_bridge_enable,
        .post_disable = dw_mipi_dsi_bridge_post_disable,
        .mode_valid   = dw_mipi_dsi_bridge_mode_valid,
        .attach       = dw_mipi_dsi_bridge_attach,
};

#ifdef CONFIG_DEBUG_FS

static void dw_mipi_dsi_debugfs_init(struct dw_mipi_dsi *dsi)
{
        dsi->debugfs = debugfs_create_dir(dev_name(dsi->dev), NULL);
        if (IS_ERR(dsi->debugfs)) {
                dev_err(dsi->dev, "failed to create debugfs root\n");
                return;
        }

        debugfs_create_bool("vpg", 0660, dsi->debugfs, &dsi->vpg);
        debugfs_create_bool("vpg_horizontal", 0660, dsi->debugfs,
                            &dsi->vpg_horizontal);
}

static void dw_mipi_dsi_debugfs_remove(struct dw_mipi_dsi *dsi)
{
        debugfs_remove_recursive(dsi->debugfs);
}

#else

static void dw_mipi_dsi_debugfs_init(struct dw_mipi_dsi *dsi) { }
static void dw_mipi_dsi_debugfs_remove(struct dw_mipi_dsi *dsi) { }

#endif /* CONFIG_DEBUG_FS */

static struct dw_mipi_dsi *
__dw_mipi_dsi_probe(struct platform_device *pdev,
                    const struct dw_mipi_dsi_plat_data *plat_data)
{
        struct device *dev = &pdev->dev;
        struct reset_control *apb_rst;
        struct dw_mipi_dsi *dsi;
        int ret;

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

        dsi->dev = dev;
        dsi->plat_data = plat_data;

        if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps ||
            !plat_data->phy_ops->get_timing) {
                DRM_ERROR("Phy not properly configured\n");
                return ERR_PTR(-ENODEV);
        }

        if (!plat_data->base) {
                dsi->base = devm_platform_ioremap_resource(pdev, 0);
                if (IS_ERR(dsi->base))
                        return ERR_PTR(-ENODEV);

        } else {
                dsi->base = plat_data->base;
        }

        dsi->pclk = devm_clk_get(dev, "pclk");
        if (IS_ERR(dsi->pclk)) {
                ret = PTR_ERR(dsi->pclk);
                dev_err(dev, "Unable to get pclk: %d\n", ret);
                return ERR_PTR(ret);
        }

        /*
         * Note that the reset was not defined in the initial device tree, so
         * we have to be prepared for it not being found.
         */
        apb_rst = devm_reset_control_get_optional_exclusive(dev, "apb");
        if (IS_ERR(apb_rst)) {
                ret = PTR_ERR(apb_rst);

                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "Unable to get reset control: %d\n", ret);

                return ERR_PTR(ret);
        }

        if (apb_rst) {
                ret = clk_prepare_enable(dsi->pclk);
                if (ret) {
                        dev_err(dev, "%s: Failed to enable pclk\n", __func__);
                        return ERR_PTR(ret);
                }

                reset_control_assert(apb_rst);
                usleep_range(10, 20);
                reset_control_deassert(apb_rst);

                clk_disable_unprepare(dsi->pclk);
        }

        dw_mipi_dsi_debugfs_init(dsi);
        pm_runtime_enable(dev);

        dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
        dsi->dsi_host.dev = dev;
        ret = mipi_dsi_host_register(&dsi->dsi_host);
        if (ret) {
                dev_err(dev, "Failed to register MIPI host: %d\n", ret);
                dw_mipi_dsi_debugfs_remove(dsi);
                return ERR_PTR(ret);
        }

        dsi->bridge.driver_private = dsi;
        dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
#ifdef CONFIG_OF
        dsi->bridge.of_node = pdev->dev.of_node;
#endif

        return dsi;
}

static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
{
        mipi_dsi_host_unregister(&dsi->dsi_host);

        pm_runtime_disable(dsi->dev);
        dw_mipi_dsi_debugfs_remove(dsi);
}

void dw_mipi_dsi_set_slave(struct dw_mipi_dsi *dsi, struct dw_mipi_dsi *slave)
{
        /* introduce controllers to each other */
        dsi->slave = slave;
        dsi->slave->master = dsi;

        /* migrate settings for already attached displays */
        dsi->slave->lanes = dsi->lanes;
        dsi->slave->channel = dsi->channel;
        dsi->slave->format = dsi->format;
        dsi->slave->mode_flags = dsi->mode_flags;
}
EXPORT_SYMBOL_GPL(dw_mipi_dsi_set_slave);

/*
 * Probe/remove API, used from platforms based on the DRM bridge API.
 */
struct dw_mipi_dsi *
dw_mipi_dsi_probe(struct platform_device *pdev,
                  const struct dw_mipi_dsi_plat_data *plat_data)
{
        return __dw_mipi_dsi_probe(pdev, plat_data);
}
EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);

void dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
{
        __dw_mipi_dsi_remove(dsi);
}
EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);

/*
 * Bind/unbind API, used from platforms based on the component framework.
 */
int dw_mipi_dsi_bind(struct dw_mipi_dsi *dsi, struct drm_encoder *encoder)
{
        int ret;

        ret = drm_bridge_attach(encoder, &dsi->bridge, NULL, 0);
        if (ret) {
                DRM_ERROR("Failed to initialize bridge with drm\n");
                return ret;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);

void dw_mipi_dsi_unbind(struct dw_mipi_dsi *dsi)
{
}
EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);

MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");
MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dw-mipi-dsi");