drivers/gpu/drm/bridge/lontium-lt9611.c

root/drivers/gpu/drm/bridge/lontium-lt9611.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2018, The Linux Foundation. All rights reserved.
 * Copyright (c) 2019-2020. Linaro Limited.
 */

#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>

#include <sound/hdmi-codec.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_edid.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_of.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>
#include <drm/display/drm_hdmi_helper.h>
#include <drm/display/drm_hdmi_state_helper.h>

#define EDID_SEG_SIZE   256
#define EDID_LEN        32
#define EDID_LOOP       8
#define KEY_DDC_ACCS_DONE 0x02
#define DDC_NO_ACK      0x50

#define LT9611_4LANES   0

struct lt9611 {
        struct device *dev;
        struct drm_bridge bridge;
        struct drm_bridge *next_bridge;

        struct regmap *regmap;

        struct device_node *dsi0_node;
        struct device_node *dsi1_node;
        struct mipi_dsi_device *dsi0;
        struct mipi_dsi_device *dsi1;

        bool ac_mode;

        struct gpio_desc *reset_gpio;
        struct gpio_desc *enable_gpio;

        bool power_on;
        bool sleep;

        struct regulator_bulk_data supplies[2];

        struct i2c_client *client;

        enum drm_connector_status status;

        u8 edid_buf[EDID_SEG_SIZE];
};

#define LT9611_PAGE_CONTROL     0xff

static const struct regmap_range_cfg lt9611_ranges[] = {
        {
                .name = "register_range",
                .range_min =  0,
                .range_max = 0x85ff,
                .selector_reg = LT9611_PAGE_CONTROL,
                .selector_mask = 0xff,
                .selector_shift = 0,
                .window_start = 0,
                .window_len = 0x100,
        },
};

static const struct regmap_config lt9611_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = 0xffff,
        .ranges = lt9611_ranges,
        .num_ranges = ARRAY_SIZE(lt9611_ranges),
};

static struct lt9611 *bridge_to_lt9611(struct drm_bridge *bridge)
{
        return container_of(bridge, struct lt9611, bridge);
}

static int lt9611_mipi_input_analog(struct lt9611 *lt9611)
{
        const struct reg_sequence reg_cfg[] = {
                { 0x8106, 0x40 }, /* port A rx current */
                { 0x810a, 0xfe }, /* port A ldo voltage set */
                { 0x810b, 0xbf }, /* enable port A lprx */
                { 0x8111, 0x40 }, /* port B rx current */
                { 0x8115, 0xfe }, /* port B ldo voltage set */
                { 0x8116, 0xbf }, /* enable port B lprx */

                { 0x811c, 0x03 }, /* PortA clk lane no-LP mode */
                { 0x8120, 0x03 }, /* PortB clk lane with-LP mode */
        };

        return regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));
}

static int lt9611_mipi_input_digital(struct lt9611 *lt9611,
                                     const struct drm_display_mode *mode)
{
        struct reg_sequence reg_cfg[] = {
                { 0x8300, LT9611_4LANES },
                { 0x830a, 0x00 },
                { 0x824f, 0x80 },
                { 0x8250, 0x10 },
                { 0x8302, 0x0a },
                { 0x8306, 0x0a },
        };

        if (lt9611->dsi1_node)
                reg_cfg[1].def = 0x03;

        return regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));
}

static void lt9611_mipi_video_setup(struct lt9611 *lt9611,
                                    const struct drm_display_mode *mode)
{
        u32 h_total, hactive, hsync_len, hfront_porch, hsync_porch;
        u32 v_total, vactive, vsync_len, vfront_porch, vsync_porch;

        h_total = mode->htotal;
        v_total = mode->vtotal;

        hactive = mode->hdisplay;
        hsync_len = mode->hsync_end - mode->hsync_start;
        hfront_porch = mode->hsync_start - mode->hdisplay;
        hsync_porch = mode->htotal - mode->hsync_start;

        vactive = mode->vdisplay;
        vsync_len = mode->vsync_end - mode->vsync_start;
        vfront_porch = mode->vsync_start - mode->vdisplay;
        vsync_porch = mode->vtotal - mode->vsync_start;

        regmap_write(lt9611->regmap, 0x830d, (u8)(v_total / 256));
        regmap_write(lt9611->regmap, 0x830e, (u8)(v_total % 256));

        regmap_write(lt9611->regmap, 0x830f, (u8)(vactive / 256));
        regmap_write(lt9611->regmap, 0x8310, (u8)(vactive % 256));

        regmap_write(lt9611->regmap, 0x8311, (u8)(h_total / 256));
        regmap_write(lt9611->regmap, 0x8312, (u8)(h_total % 256));

        regmap_write(lt9611->regmap, 0x8313, (u8)(hactive / 256));
        regmap_write(lt9611->regmap, 0x8314, (u8)(hactive % 256));

        regmap_write(lt9611->regmap, 0x8315, (u8)(vsync_len % 256));
        regmap_write(lt9611->regmap, 0x8316, (u8)(hsync_len % 256));

        regmap_write(lt9611->regmap, 0x8317, (u8)(vfront_porch % 256));

        regmap_write(lt9611->regmap, 0x8318, (u8)(vsync_porch % 256));

        regmap_write(lt9611->regmap, 0x8319, (u8)(hfront_porch % 256));

        regmap_write(lt9611->regmap, 0x831a, (u8)(hsync_porch / 256) |
                                                ((hfront_porch / 256) << 4));
        regmap_write(lt9611->regmap, 0x831b, (u8)(hsync_porch % 256));
}

static void lt9611_pcr_setup(struct lt9611 *lt9611, const struct drm_display_mode *mode, unsigned int postdiv)
{
        unsigned int pcr_m = mode->clock * 5 * postdiv / 27000;
        const struct reg_sequence reg_cfg[] = {
                { 0x830b, 0x01 },
                { 0x830c, 0x10 },
                { 0x8348, 0x00 },
                { 0x8349, 0x81 },

                /* stage 1 */
                { 0x8321, 0x4a },
                { 0x8324, 0x71 },
                { 0x8325, 0x30 },
                { 0x832a, 0x01 },

                /* stage 2 */
                { 0x834a, 0x40 },

                /* MK limit */
                { 0x832d, 0x38 },
                { 0x8331, 0x08 },
        };
        u8 pol = 0x10;

        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
                pol |= 0x2;
        if (mode->flags & DRM_MODE_FLAG_NVSYNC)
                pol |= 0x1;
        regmap_write(lt9611->regmap, 0x831d, pol);

        regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));
        if (lt9611->dsi1_node) {
                unsigned int hact = mode->hdisplay;

                hact >>= 2;
                hact += 0x50;
                hact = min(hact, 0x3e0U);
                regmap_write(lt9611->regmap, 0x830b, hact / 256);
                regmap_write(lt9611->regmap, 0x830c, hact % 256);
                regmap_write(lt9611->regmap, 0x8348, hact / 256);
                regmap_write(lt9611->regmap, 0x8349, hact % 256);
        }

        regmap_write(lt9611->regmap, 0x8326, pcr_m);

        /* pcr rst */
        regmap_write(lt9611->regmap, 0x8011, 0x5a);
        regmap_write(lt9611->regmap, 0x8011, 0xfa);
}

static int lt9611_pll_setup(struct lt9611 *lt9611, const struct drm_display_mode *mode, unsigned int *postdiv)
{
        unsigned int pclk = mode->clock;
        const struct reg_sequence reg_cfg[] = {
                /* txpll init */
                { 0x8123, 0x40 },
                { 0x8124, 0x64 },
                { 0x8125, 0x80 },
                { 0x8126, 0x55 },
                { 0x812c, 0x37 },
                { 0x812f, 0x01 },
                { 0x8126, 0x55 },
                { 0x8127, 0x66 },
                { 0x8128, 0x88 },
                { 0x812a, 0x20 },
        };

        regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));

        if (pclk > 150000) {
                regmap_write(lt9611->regmap, 0x812d, 0x88);
                *postdiv = 1;
        } else if (pclk > 70000) {
                regmap_write(lt9611->regmap, 0x812d, 0x99);
                *postdiv = 2;
        } else {
                regmap_write(lt9611->regmap, 0x812d, 0xaa);
                *postdiv = 4;
        }

        /*
         * first divide pclk by 2 first
         *  - write divide by 64k to 19:16 bits which means shift by 17
         *  - write divide by 256 to 15:8 bits which means shift by 9
         *  - write remainder to 7:0 bits, which means shift by 1
         */
        regmap_write(lt9611->regmap, 0x82e3, pclk >> 17); /* pclk[19:16] */
        regmap_write(lt9611->regmap, 0x82e4, pclk >> 9);  /* pclk[15:8]  */
        regmap_write(lt9611->regmap, 0x82e5, pclk >> 1);  /* pclk[7:0]   */

        regmap_write(lt9611->regmap, 0x82de, 0x20);
        regmap_write(lt9611->regmap, 0x82de, 0xe0);

        regmap_write(lt9611->regmap, 0x8016, 0xf1);
        regmap_write(lt9611->regmap, 0x8016, 0xf3);

        return 0;
}

static int lt9611_read_video_check(struct lt9611 *lt9611, unsigned int reg)
{
        unsigned int temp, temp2;
        int ret;

        ret = regmap_read(lt9611->regmap, reg, &temp);
        if (ret)
                return ret;
        temp <<= 8;
        ret = regmap_read(lt9611->regmap, reg + 1, &temp2);
        if (ret)
                return ret;

        return (temp + temp2);
}

static int lt9611_video_check(struct lt9611 *lt9611)
{
        u32 v_total, vactive, hactive_a, hactive_b, h_total_sysclk;
        int temp;

        /* top module video check */

        /* vactive */
        temp = lt9611_read_video_check(lt9611, 0x8282);
        if (temp < 0)
                goto end;
        vactive = temp;

        /* v_total */
        temp = lt9611_read_video_check(lt9611, 0x826c);
        if (temp < 0)
                goto end;
        v_total = temp;

        /* h_total_sysclk */
        temp = lt9611_read_video_check(lt9611, 0x8286);
        if (temp < 0)
                goto end;
        h_total_sysclk = temp;

        /* hactive_a */
        temp = lt9611_read_video_check(lt9611, 0x8382);
        if (temp < 0)
                goto end;
        hactive_a = temp / 3;

        /* hactive_b */
        temp = lt9611_read_video_check(lt9611, 0x8386);
        if (temp < 0)
                goto end;
        hactive_b = temp / 3;

        dev_info(lt9611->dev,
                 "video check: hactive_a=%d, hactive_b=%d, vactive=%d, v_total=%d, h_total_sysclk=%d\n",
                 hactive_a, hactive_b, vactive, v_total, h_total_sysclk);

        return 0;

end:
        dev_err(lt9611->dev, "read video check error\n");
        return temp;
}

static void lt9611_hdmi_tx_digital(struct lt9611 *lt9611, bool is_hdmi)
{
        if (is_hdmi)
                regmap_write(lt9611->regmap, 0x82d6, 0x8c);
        else
                regmap_write(lt9611->regmap, 0x82d6, 0x0c);
        regmap_write(lt9611->regmap, 0x82d7, 0x04);
}

static void lt9611_hdmi_tx_phy(struct lt9611 *lt9611)
{
        struct reg_sequence reg_cfg[] = {
                { 0x8130, 0x6a },
                { 0x8131, 0x44 }, /* HDMI DC mode */
                { 0x8132, 0x4a },
                { 0x8133, 0x0b },
                { 0x8134, 0x00 },
                { 0x8135, 0x00 },
                { 0x8136, 0x00 },
                { 0x8137, 0x44 },
                { 0x813f, 0x0f },
                { 0x8140, 0xa0 },
                { 0x8141, 0xa0 },
                { 0x8142, 0xa0 },
                { 0x8143, 0xa0 },
                { 0x8144, 0x0a },
        };

        /* HDMI AC mode */
        if (lt9611->ac_mode)
                reg_cfg[2].def = 0x73;

        regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));
}

static irqreturn_t lt9611_irq_thread_handler(int irq, void *dev_id)
{
        struct lt9611 *lt9611 = dev_id;
        unsigned int irq_flag0 = 0;
        unsigned int irq_flag3 = 0;

        regmap_read(lt9611->regmap, 0x820f, &irq_flag3);
        regmap_read(lt9611->regmap, 0x820c, &irq_flag0);

        /* hpd changed low */
        if (irq_flag3 & 0x80) {
                dev_info(lt9611->dev, "hdmi cable disconnected\n");

                regmap_write(lt9611->regmap, 0x8207, 0xbf);
                regmap_write(lt9611->regmap, 0x8207, 0x3f);
        }

        /* hpd changed high */
        if (irq_flag3 & 0x40) {
                dev_info(lt9611->dev, "hdmi cable connected\n");

                regmap_write(lt9611->regmap, 0x8207, 0x7f);
                regmap_write(lt9611->regmap, 0x8207, 0x3f);
        }

        if (irq_flag3 & 0xc0 && lt9611->bridge.dev)
                drm_kms_helper_hotplug_event(lt9611->bridge.dev);

        /* video input changed */
        if (irq_flag0 & 0x01) {
                dev_info(lt9611->dev, "video input changed\n");
                regmap_write(lt9611->regmap, 0x829e, 0xff);
                regmap_write(lt9611->regmap, 0x829e, 0xf7);
                regmap_write(lt9611->regmap, 0x8204, 0xff);
                regmap_write(lt9611->regmap, 0x8204, 0xfe);
        }

        return IRQ_HANDLED;
}

static void lt9611_enable_hpd_interrupts(struct lt9611 *lt9611)
{
        unsigned int val;

        regmap_read(lt9611->regmap, 0x8203, &val);

        val &= ~0xc0;
        regmap_write(lt9611->regmap, 0x8203, val);
        regmap_write(lt9611->regmap, 0x8207, 0xff); /* clear */
        regmap_write(lt9611->regmap, 0x8207, 0x3f);
}

static void lt9611_sleep_setup(struct lt9611 *lt9611)
{
        const struct reg_sequence sleep_setup[] = {
                { 0x8024, 0x76 },
                { 0x8023, 0x01 },
                { 0x8157, 0x03 }, /* set addr pin as output */
                { 0x8149, 0x0b },

                { 0x8102, 0x48 }, /* MIPI Rx power down */
                { 0x8123, 0x80 },
                { 0x8130, 0x00 },
                { 0x8011, 0x0a },
        };

        regmap_multi_reg_write(lt9611->regmap,
                               sleep_setup, ARRAY_SIZE(sleep_setup));
        lt9611->sleep = true;
}

static int lt9611_power_on(struct lt9611 *lt9611)
{
        int ret;
        const struct reg_sequence seq[] = {
                /* LT9611_System_Init */
                { 0x8101, 0x18 }, /* sel xtal clock */

                /* timer for frequency meter */
                { 0x821b, 0x69 }, /* timer 2 */
                { 0x821c, 0x78 },
                { 0x82cb, 0x69 }, /* timer 1 */
                { 0x82cc, 0x78 },

                /* irq init */
                { 0x8251, 0x01 },
                { 0x8258, 0x0a }, /* hpd irq */
                { 0x8259, 0x80 }, /* hpd debounce width */
                { 0x829e, 0xf7 }, /* video check irq */

                /* power consumption for work */
                { 0x8004, 0xf0 },
                { 0x8006, 0xf0 },
                { 0x800a, 0x80 },
                { 0x800b, 0x40 },
                { 0x800d, 0xef },
                { 0x8011, 0xfa },
        };

        if (lt9611->power_on)
                return 0;

        ret = regmap_multi_reg_write(lt9611->regmap, seq, ARRAY_SIZE(seq));
        if (!ret)
                lt9611->power_on = true;

        return ret;
}

static int lt9611_power_off(struct lt9611 *lt9611)
{
        int ret;

        ret = regmap_write(lt9611->regmap, 0x8130, 0x6a);
        if (!ret)
                lt9611->power_on = false;

        return ret;
}

static void lt9611_reset(struct lt9611 *lt9611)
{
        gpiod_set_value_cansleep(lt9611->reset_gpio, 1);
        msleep(20);

        gpiod_set_value_cansleep(lt9611->reset_gpio, 0);
        msleep(20);

        gpiod_set_value_cansleep(lt9611->reset_gpio, 1);
        msleep(100);
}

static void lt9611_assert_5v(struct lt9611 *lt9611)
{
        if (!lt9611->enable_gpio)
                return;

        gpiod_set_value_cansleep(lt9611->enable_gpio, 1);
        msleep(20);
}

static int lt9611_regulator_init(struct lt9611 *lt9611)
{
        int ret;

        lt9611->supplies[0].supply = "vdd";
        lt9611->supplies[1].supply = "vcc";

        ret = devm_regulator_bulk_get(lt9611->dev, 2, lt9611->supplies);
        if (ret < 0)
                return ret;

        return regulator_set_load(lt9611->supplies[0].consumer, 300000);
}

static int lt9611_regulator_enable(struct lt9611 *lt9611)
{
        int ret;

        ret = regulator_enable(lt9611->supplies[0].consumer);
        if (ret < 0)
                return ret;

        usleep_range(1000, 10000);

        ret = regulator_enable(lt9611->supplies[1].consumer);
        if (ret < 0) {
                regulator_disable(lt9611->supplies[0].consumer);
                return ret;
        }

        return 0;
}

static enum drm_connector_status
lt9611_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        unsigned int reg_val = 0;
        int connected = 0;

        regmap_read(lt9611->regmap, 0x825e, &reg_val);
        connected  = (reg_val & (BIT(2) | BIT(0)));

        lt9611->status = connected ?  connector_status_connected :
                                connector_status_disconnected;

        return lt9611->status;
}

static int lt9611_read_edid(struct lt9611 *lt9611)
{
        unsigned int temp;
        int ret = 0;
        int i, j;

        /* memset to clear old buffer, if any */
        memset(lt9611->edid_buf, 0, sizeof(lt9611->edid_buf));

        regmap_write(lt9611->regmap, 0x8503, 0xc9);

        /* 0xA0 is EDID device address */
        regmap_write(lt9611->regmap, 0x8504, 0xa0);
        /* 0x00 is EDID offset address */
        regmap_write(lt9611->regmap, 0x8505, 0x00);

        /* length for read */
        regmap_write(lt9611->regmap, 0x8506, EDID_LEN);
        regmap_write(lt9611->regmap, 0x8514, 0x7f);

        for (i = 0; i < EDID_LOOP; i++) {
                /* offset address */
                regmap_write(lt9611->regmap, 0x8505, i * EDID_LEN);
                regmap_write(lt9611->regmap, 0x8507, 0x36);
                regmap_write(lt9611->regmap, 0x8507, 0x31);
                regmap_write(lt9611->regmap, 0x8507, 0x37);
                usleep_range(5000, 10000);

                regmap_read(lt9611->regmap, 0x8540, &temp);

                if (temp & KEY_DDC_ACCS_DONE) {
                        for (j = 0; j < EDID_LEN; j++) {
                                regmap_read(lt9611->regmap, 0x8583, &temp);
                                lt9611->edid_buf[i * EDID_LEN + j] = temp;
                        }

                } else if (temp & DDC_NO_ACK) { /* DDC No Ack or Abitration lost */
                        dev_err(lt9611->dev, "read edid failed: no ack\n");
                        ret = -EIO;
                        goto end;

                } else {
                        dev_err(lt9611->dev, "read edid failed: access not done\n");
                        ret = -EIO;
                        goto end;
                }
        }

end:
        regmap_write(lt9611->regmap, 0x8507, 0x1f);
        return ret;
}

static int
lt9611_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
{
        struct lt9611 *lt9611 = data;
        int ret;

        if (len > 128)
                return -EINVAL;

        /* supports up to 1 extension block */
        /* TODO: add support for more extension blocks */
        if (block > 1)
                return -EINVAL;

        if (block == 0) {
                ret = lt9611_read_edid(lt9611);
                if (ret) {
                        dev_err(lt9611->dev, "edid read failed\n");
                        return ret;
                }
        }

        block %= 2;
        memcpy(buf, lt9611->edid_buf + (block * 128), len);

        return 0;
}

/* bridge funcs */
static void lt9611_bridge_atomic_enable(struct drm_bridge *bridge,
                                        struct drm_atomic_state *state)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        struct drm_connector *connector;
        struct drm_connector_state *conn_state;
        struct drm_crtc_state *crtc_state;
        struct drm_display_mode *mode;
        unsigned int postdiv;

        connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
        if (WARN_ON(!connector))
                return;

        conn_state = drm_atomic_get_new_connector_state(state, connector);
        if (WARN_ON(!conn_state))
                return;

        crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
        if (WARN_ON(!crtc_state))
                return;

        mode = &crtc_state->adjusted_mode;

        lt9611_mipi_input_digital(lt9611, mode);
        lt9611_pll_setup(lt9611, mode, &postdiv);
        lt9611_mipi_video_setup(lt9611, mode);
        lt9611_pcr_setup(lt9611, mode, postdiv);

        if (lt9611_power_on(lt9611)) {
                dev_err(lt9611->dev, "power on failed\n");
                return;
        }

        lt9611_mipi_input_analog(lt9611);
        drm_atomic_helper_connector_hdmi_update_infoframes(connector, state);
        lt9611_hdmi_tx_digital(lt9611, connector->display_info.is_hdmi);
        lt9611_hdmi_tx_phy(lt9611);

        msleep(500);

        lt9611_video_check(lt9611);

        /* Enable HDMI output */
        regmap_write(lt9611->regmap, 0x8130, 0xea);
}

static void lt9611_bridge_atomic_disable(struct drm_bridge *bridge,
                                         struct drm_atomic_state *state)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        int ret;

        /* Disable HDMI output */
        ret = regmap_write(lt9611->regmap, 0x8130, 0x6a);
        if (ret) {
                dev_err(lt9611->dev, "video on failed\n");
                return;
        }

        if (lt9611_power_off(lt9611)) {
                dev_err(lt9611->dev, "power on failed\n");
                return;
        }
}

static struct mipi_dsi_device *lt9611_attach_dsi(struct lt9611 *lt9611,
                                                 struct device_node *dsi_node)
{
        const struct mipi_dsi_device_info info = { "lt9611", 0, lt9611->dev->of_node};
        struct mipi_dsi_device *dsi;
        struct mipi_dsi_host *host;
        struct device *dev = lt9611->dev;
        int ret;

        host = of_find_mipi_dsi_host_by_node(dsi_node);
        if (!host)
                return ERR_PTR(dev_err_probe(lt9611->dev, -EPROBE_DEFER, "failed to find dsi host\n"));

        dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
        if (IS_ERR(dsi)) {
                dev_err(lt9611->dev, "failed to create dsi device\n");
                return dsi;
        }

        dsi->lanes = 4;
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
                          MIPI_DSI_MODE_VIDEO_HSE;

        ret = devm_mipi_dsi_attach(dev, dsi);
        if (ret < 0) {
                dev_err(dev, "failed to attach dsi to host\n");
                return ERR_PTR(ret);
        }

        return dsi;
}

static int lt9611_bridge_attach(struct drm_bridge *bridge,
                                struct drm_encoder *encoder,
                                enum drm_bridge_attach_flags flags)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        return drm_bridge_attach(encoder, lt9611->next_bridge,
                                 bridge, flags);
}

static enum drm_mode_status lt9611_bridge_mode_valid(struct drm_bridge *bridge,
                                                     const struct drm_display_info *info,
                                                     const struct drm_display_mode *mode)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        if (mode->hdisplay > 3840)
                return MODE_BAD_HVALUE;

        if (mode->hdisplay > 2000 && !lt9611->dsi1_node)
                return MODE_PANEL;

        return MODE_OK;
}

static void lt9611_bridge_atomic_pre_enable(struct drm_bridge *bridge,
                                            struct drm_atomic_state *state)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        static const struct reg_sequence reg_cfg[] = {
                { 0x8102, 0x12 },
                { 0x8123, 0x40 },
                { 0x8130, 0xea },
                { 0x8011, 0xfa },
        };

        if (!lt9611->sleep)
                return;

        regmap_multi_reg_write(lt9611->regmap,
                               reg_cfg, ARRAY_SIZE(reg_cfg));

        lt9611->sleep = false;
}

static void lt9611_bridge_atomic_post_disable(struct drm_bridge *bridge,
                                              struct drm_atomic_state *state)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        lt9611_sleep_setup(lt9611);
}

static const struct drm_edid *lt9611_bridge_edid_read(struct drm_bridge *bridge,
                                                      struct drm_connector *connector)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        lt9611_power_on(lt9611);
        return drm_edid_read_custom(connector, lt9611_get_edid_block, lt9611);
}

static void lt9611_bridge_hpd_enable(struct drm_bridge *bridge)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        lt9611_enable_hpd_interrupts(lt9611);
}

#define MAX_INPUT_SEL_FORMATS   1

static u32 *
lt9611_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
                                 struct drm_bridge_state *bridge_state,
                                 struct drm_crtc_state *crtc_state,
                                 struct drm_connector_state *conn_state,
                                 u32 output_fmt,
                                 unsigned int *num_input_fmts)
{
        u32 *input_fmts;

        *num_input_fmts = 0;

        input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
                             GFP_KERNEL);
        if (!input_fmts)
                return NULL;

        /* This is the DSI-end bus format */
        input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
        *num_input_fmts = 1;

        return input_fmts;
}

/*
 * Other working frames:
 * - 0x01, 0x84df
 * - 0x04, 0x84c0
 */
#define LT9611_INFOFRAME_AUDIO  0x02
#define LT9611_INFOFRAME_AVI    0x08
#define LT9611_INFOFRAME_SPD    0x10
#define LT9611_INFOFRAME_HDMI   0x20

static int lt9611_hdmi_clear_audio_infoframe(struct drm_bridge *bridge)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_AUDIO, 0);

        return 0;
}

static int lt9611_hdmi_clear_avi_infoframe(struct drm_bridge *bridge)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_AVI, 0);

        return 0;
}

static int lt9611_hdmi_clear_spd_infoframe(struct drm_bridge *bridge)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_SPD, 0);

        return 0;
}

static int lt9611_hdmi_clear_hdmi_infoframe(struct drm_bridge *bridge)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_HDMI, 0);

        return 0;
}

static int lt9611_hdmi_write_audio_infoframe(struct drm_bridge *bridge,
                                             const u8 *buffer, size_t len)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        int i;

        for (i = 0; i < len; i++)
                regmap_write(lt9611->regmap, 0x84b2 + i, buffer[i]);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_AUDIO, LT9611_INFOFRAME_AUDIO);

        return 0;
}

static int lt9611_hdmi_write_avi_infoframe(struct drm_bridge *bridge,
                                           const u8 *buffer, size_t len)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        int i;

        for (i = 0; i < len; i++)
                regmap_write(lt9611->regmap, 0x8440 + i, buffer[i]);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_AVI, LT9611_INFOFRAME_AVI);

        return 0;
}

static int lt9611_hdmi_write_spd_infoframe(struct drm_bridge *bridge,
                                           const u8 *buffer, size_t len)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        int i;

        for (i = 0; i < len; i++)
                regmap_write(lt9611->regmap, 0x8493 + i, buffer[i]);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_SPD, LT9611_INFOFRAME_SPD);

        return 0;
}

static int lt9611_hdmi_write_hdmi_infoframe(struct drm_bridge *bridge,
                                            const u8 *buffer, size_t len)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
        int i;

        for (i = 0; i < len; i++)
                regmap_write(lt9611->regmap, 0x8474 + i, buffer[i]);

        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_HDMI, LT9611_INFOFRAME_HDMI);

        return 0;
}

static enum drm_mode_status
lt9611_hdmi_tmds_char_rate_valid(const struct drm_bridge *bridge,
                                 const struct drm_display_mode *mode,
                                 unsigned long long tmds_rate)
{
        /* 297 MHz for 4k@30 mode */
        if (tmds_rate > 297000000)
                return MODE_CLOCK_HIGH;

        return MODE_OK;
}

static int lt9611_hdmi_audio_startup(struct drm_bridge *bridge,
                                     struct drm_connector *connector)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        regmap_write(lt9611->regmap, 0x82d6, 0x8c);
        regmap_write(lt9611->regmap, 0x82d7, 0x04);

        regmap_write(lt9611->regmap, 0x8406, 0x08);
        regmap_write(lt9611->regmap, 0x8407, 0x10);

        regmap_write(lt9611->regmap, 0x8434, 0xd5);

        return 0;
}

static int lt9611_hdmi_audio_prepare(struct drm_bridge *bridge,
                                     struct drm_connector *connector,
                                     struct hdmi_codec_daifmt *fmt,
                                     struct hdmi_codec_params *hparms)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        if (hparms->sample_rate == 48000)
                regmap_write(lt9611->regmap, 0x840f, 0x2b);
        else if (hparms->sample_rate == 96000)
                regmap_write(lt9611->regmap, 0x840f, 0xab);
        else
                return -EINVAL;

        regmap_write(lt9611->regmap, 0x8435, 0x00);
        regmap_write(lt9611->regmap, 0x8436, 0x18);
        regmap_write(lt9611->regmap, 0x8437, 0x00);

        return drm_atomic_helper_connector_hdmi_update_audio_infoframe(connector,
                                                                       &hparms->cea);
}

static void lt9611_hdmi_audio_shutdown(struct drm_bridge *bridge,
                                       struct drm_connector *connector)
{
        struct lt9611 *lt9611 = bridge_to_lt9611(bridge);

        drm_atomic_helper_connector_hdmi_clear_audio_infoframe(connector);

        regmap_write(lt9611->regmap, 0x8406, 0x00);
        regmap_write(lt9611->regmap, 0x8407, 0x00);
}

static const struct drm_bridge_funcs lt9611_bridge_funcs = {
        .attach = lt9611_bridge_attach,
        .mode_valid = lt9611_bridge_mode_valid,
        .detect = lt9611_bridge_detect,
        .edid_read = lt9611_bridge_edid_read,
        .hpd_enable = lt9611_bridge_hpd_enable,

        .atomic_pre_enable = lt9611_bridge_atomic_pre_enable,
        .atomic_enable = lt9611_bridge_atomic_enable,
        .atomic_disable = lt9611_bridge_atomic_disable,
        .atomic_post_disable = lt9611_bridge_atomic_post_disable,
        .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
        .atomic_reset = drm_atomic_helper_bridge_reset,
        .atomic_get_input_bus_fmts = lt9611_atomic_get_input_bus_fmts,

        .hdmi_tmds_char_rate_valid = lt9611_hdmi_tmds_char_rate_valid,
        .hdmi_write_audio_infoframe = lt9611_hdmi_write_audio_infoframe,
        .hdmi_clear_audio_infoframe = lt9611_hdmi_clear_audio_infoframe,
        .hdmi_write_avi_infoframe = lt9611_hdmi_write_avi_infoframe,
        .hdmi_clear_avi_infoframe = lt9611_hdmi_clear_avi_infoframe,
        .hdmi_write_spd_infoframe = lt9611_hdmi_write_spd_infoframe,
        .hdmi_clear_spd_infoframe = lt9611_hdmi_clear_spd_infoframe,
        .hdmi_write_hdmi_infoframe = lt9611_hdmi_write_hdmi_infoframe,
        .hdmi_clear_hdmi_infoframe = lt9611_hdmi_clear_hdmi_infoframe,

        .hdmi_audio_startup = lt9611_hdmi_audio_startup,
        .hdmi_audio_prepare = lt9611_hdmi_audio_prepare,
        .hdmi_audio_shutdown = lt9611_hdmi_audio_shutdown,
};

static int lt9611_parse_dt(struct device *dev,
                           struct lt9611 *lt9611)
{
        lt9611->dsi0_node = of_graph_get_remote_node(dev->of_node, 0, -1);
        if (!lt9611->dsi0_node) {
                dev_err(lt9611->dev, "failed to get remote node for primary dsi\n");
                return -ENODEV;
        }

        lt9611->dsi1_node = of_graph_get_remote_node(dev->of_node, 1, -1);

        lt9611->ac_mode = of_property_read_bool(dev->of_node, "lt,ac-mode");

        return drm_of_find_panel_or_bridge(dev->of_node, 2, -1, NULL, &lt9611->next_bridge);
}

static int lt9611_gpio_init(struct lt9611 *lt9611)
{
        struct device *dev = lt9611->dev;

        lt9611->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(lt9611->reset_gpio)) {
                dev_err(dev, "failed to acquire reset gpio\n");
                return PTR_ERR(lt9611->reset_gpio);
        }

        lt9611->enable_gpio = devm_gpiod_get_optional(dev, "enable",
                                                      GPIOD_OUT_LOW);
        if (IS_ERR(lt9611->enable_gpio)) {
                dev_err(dev, "failed to acquire enable gpio\n");
                return PTR_ERR(lt9611->enable_gpio);
        }

        return 0;
}

static int lt9611_read_device_rev(struct lt9611 *lt9611)
{
        unsigned int rev;
        int ret;

        regmap_write(lt9611->regmap, 0x80ee, 0x01);
        ret = regmap_read(lt9611->regmap, 0x8002, &rev);
        if (ret)
                dev_err(lt9611->dev, "failed to read revision: %d\n", ret);
        else
                dev_info(lt9611->dev, "LT9611 revision: 0x%x\n", rev);

        return ret;
}

static int lt9611_probe(struct i2c_client *client)
{
        struct lt9611 *lt9611;
        struct device *dev = &client->dev;
        int ret;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_err(dev, "device doesn't support I2C\n");
                return -ENODEV;
        }

        lt9611 = devm_drm_bridge_alloc(dev, struct lt9611, bridge,
                                       &lt9611_bridge_funcs);
        if (IS_ERR(lt9611))
                return PTR_ERR(lt9611);

        lt9611->dev = dev;
        lt9611->client = client;
        lt9611->sleep = false;

        lt9611->regmap = devm_regmap_init_i2c(client, &lt9611_regmap_config);
        if (IS_ERR(lt9611->regmap)) {
                dev_err(lt9611->dev, "regmap i2c init failed\n");
                return PTR_ERR(lt9611->regmap);
        }

        ret = lt9611_parse_dt(dev, lt9611);
        if (ret) {
                dev_err(dev, "failed to parse device tree\n");
                return ret;
        }

        ret = lt9611_gpio_init(lt9611);
        if (ret < 0)
                goto err_of_put;

        ret = lt9611_regulator_init(lt9611);
        if (ret < 0)
                goto err_of_put;

        lt9611_assert_5v(lt9611);

        ret = lt9611_regulator_enable(lt9611);
        if (ret)
                goto err_of_put;

        lt9611_reset(lt9611);

        ret = lt9611_read_device_rev(lt9611);
        if (ret) {
                dev_err(dev, "failed to read chip rev\n");
                goto err_disable_regulators;
        }

        ret = devm_request_threaded_irq(dev, client->irq, NULL,
                                        lt9611_irq_thread_handler,
                                        IRQF_ONESHOT, "lt9611", lt9611);
        if (ret) {
                dev_err(dev, "failed to request irq\n");
                goto err_disable_regulators;
        }

        i2c_set_clientdata(client, lt9611);

        /* Disable Audio InfoFrame, enabled by default */
        regmap_update_bits(lt9611->regmap, 0x843d, LT9611_INFOFRAME_AUDIO, 0);

        lt9611->bridge.of_node = client->dev.of_node;
        lt9611->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
                             DRM_BRIDGE_OP_HPD | DRM_BRIDGE_OP_MODES |
                             DRM_BRIDGE_OP_HDMI | DRM_BRIDGE_OP_HDMI_AUDIO |
                             DRM_BRIDGE_OP_HDMI_SPD_INFOFRAME;
        lt9611->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
        lt9611->bridge.vendor = "Lontium";
        lt9611->bridge.product = "LT9611";
        lt9611->bridge.hdmi_audio_dev = dev;
        lt9611->bridge.hdmi_audio_max_i2s_playback_channels = 8;
        lt9611->bridge.hdmi_audio_dai_port = 2;

        drm_bridge_add(&lt9611->bridge);

        /* Attach primary DSI */
        lt9611->dsi0 = lt9611_attach_dsi(lt9611, lt9611->dsi0_node);
        if (IS_ERR(lt9611->dsi0)) {
                ret = PTR_ERR(lt9611->dsi0);
                goto err_remove_bridge;
        }

        /* Attach secondary DSI, if specified */
        if (lt9611->dsi1_node) {
                lt9611->dsi1 = lt9611_attach_dsi(lt9611, lt9611->dsi1_node);
                if (IS_ERR(lt9611->dsi1)) {
                        ret = PTR_ERR(lt9611->dsi1);
                        goto err_remove_bridge;
                }
        }

        lt9611_enable_hpd_interrupts(lt9611);

        return 0;

err_remove_bridge:
        drm_bridge_remove(&lt9611->bridge);

err_disable_regulators:
        regulator_bulk_disable(ARRAY_SIZE(lt9611->supplies), lt9611->supplies);

err_of_put:
        of_node_put(lt9611->dsi1_node);
        of_node_put(lt9611->dsi0_node);

        return ret;
}

static void lt9611_remove(struct i2c_client *client)
{
        struct lt9611 *lt9611 = i2c_get_clientdata(client);

        disable_irq(client->irq);
        drm_bridge_remove(&lt9611->bridge);

        regulator_bulk_disable(ARRAY_SIZE(lt9611->supplies), lt9611->supplies);

        of_node_put(lt9611->dsi1_node);
        of_node_put(lt9611->dsi0_node);
}

static const struct i2c_device_id lt9611_id[] = {
        { "lontium,lt9611" },
        {}
};
MODULE_DEVICE_TABLE(i2c, lt9611_id);

static const struct of_device_id lt9611_match_table[] = {
        { .compatible = "lontium,lt9611" },
        { }
};
MODULE_DEVICE_TABLE(of, lt9611_match_table);

static struct i2c_driver lt9611_driver = {
        .driver = {
                .name = "lt9611",
                .of_match_table = lt9611_match_table,
        },
        .probe = lt9611_probe,
        .remove = lt9611_remove,
        .id_table = lt9611_id,
};
module_i2c_driver(lt9611_driver);

MODULE_DESCRIPTION("Lontium LT9611 DSI/HDMI bridge driver");
MODULE_LICENSE("GPL v2");