/*
 * Parade PS8622 eDP/LVDS bridge driver
 *
 * Copyright (C) 2014 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drmP.h>

/* Brightness scale on the Parade chip */
#define PS8622_MAX_BRIGHTNESS 0xff

/* Timings taken from the version 1.7 datasheet for the PS8622/PS8625 */
#define PS8622_POWER_RISE_T1_MIN_US 10
#define PS8622_POWER_RISE_T1_MAX_US 10000
#define PS8622_RST_HIGH_T2_MIN_US 3000
#define PS8622_RST_HIGH_T2_MAX_US 30000
#define PS8622_PWMO_END_T12_MS 200
#define PS8622_POWER_FALL_T16_MAX_US 10000
#define PS8622_POWER_OFF_T17_MS 500

#if ((PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US) > \
        (PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US))
#error "T2.min + T1.max must be less than T2.max + T1.min"
#endif

struct ps8622_bridge {
        struct drm_connector connector;
        struct i2c_client *client;
        struct drm_bridge bridge;
        struct drm_panel *panel;
        struct regulator *v12;
        struct backlight_device *bl;

        struct gpio_desc *gpio_slp;
        struct gpio_desc *gpio_rst;

        u32 max_lane_count;
        u32 lane_count;

        bool enabled;
};

static inline struct ps8622_bridge *
                bridge_to_ps8622(struct drm_bridge *bridge)
{
        return container_of(bridge, struct ps8622_bridge, bridge);
}

static inline struct ps8622_bridge *
                connector_to_ps8622(struct drm_connector *connector)
{
        return container_of(connector, struct ps8622_bridge, connector);
}

static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
{
        int ret;
        struct i2c_adapter *adap = client->adapter;
        struct i2c_msg msg;
        u8 data[] = {reg, val};

        msg.addr = client->addr + page;
        msg.flags = 0;
        msg.len = sizeof(data);
        msg.buf = data;

        ret = i2c_transfer(adap, &msg, 1);
        if (ret != 1)
                pr_warn("PS8622 I2C write (0x%02x,0x%02x,0x%02x) failed: %d\n",
                        client->addr + page, reg, val, ret);
        return !(ret == 1);
}

static int ps8622_send_config(struct ps8622_bridge *ps8622)
{
        struct i2c_client *cl = ps8622->client;
        int err = 0;

        /* HPD low */
        err = ps8622_set(cl, 0x02, 0xa1, 0x01);
        if (err)
                goto error;

        /* SW setting: [1:0] SW output 1.2V voltage is lower to 96% */
        err = ps8622_set(cl, 0x04, 0x14, 0x01);
        if (err)
                goto error;

        /* RCO SS setting: [5:4] = b01 0.5%, b10 1%, b11 1.5% */
        err = ps8622_set(cl, 0x04, 0xe3, 0x20);
        if (err)
                goto error;

        /* [7] RCO SS enable */
        err = ps8622_set(cl, 0x04, 0xe2, 0x80);
        if (err)
                goto error;

        /* RPHY Setting
         * [3:2] CDR tune wait cycle before measure for fine tune
         * b00: 1us b01: 0.5us b10:2us, b11: 4us
         */
        err = ps8622_set(cl, 0x04, 0x8a, 0x0c);
        if (err)
                goto error;

        /* [3] RFD always on */
        err = ps8622_set(cl, 0x04, 0x89, 0x08);
        if (err)
                goto error;

        /* CTN lock in/out: 20000ppm/80000ppm. Lock out 2 times. */
        err = ps8622_set(cl, 0x04, 0x71, 0x2d);
        if (err)
                goto error;

        /* 2.7G CDR settings: NOF=40LSB for HBR CDR  setting */
        err = ps8622_set(cl, 0x04, 0x7d, 0x07);
        if (err)
                goto error;

        /* [1:0] Fmin=+4bands */
        err = ps8622_set(cl, 0x04, 0x7b, 0x00);
        if (err)
                goto error;

        /* [7:5] DCO_FTRNG=+-40% */
        err = ps8622_set(cl, 0x04, 0x7a, 0xfd);
        if (err)
                goto error;

        /* 1.62G CDR settings: [5:2]NOF=64LSB [1:0]DCO scale is 2/5 */
        err = ps8622_set(cl, 0x04, 0xc0, 0x12);
        if (err)
                goto error;

        /* Gitune=-37% */
        err = ps8622_set(cl, 0x04, 0xc1, 0x92);
        if (err)
                goto error;

        /* Fbstep=100% */
        err = ps8622_set(cl, 0x04, 0xc2, 0x1c);
        if (err)
                goto error;

        /* [7] LOS signal disable */
        err = ps8622_set(cl, 0x04, 0x32, 0x80);
        if (err)
                goto error;

        /* RPIO Setting: [7:4] LVDS driver bias current : 75% (250mV swing) */
        err = ps8622_set(cl, 0x04, 0x00, 0xb0);
        if (err)
                goto error;

        /* [7:6] Right-bar GPIO output strength is 8mA */
        err = ps8622_set(cl, 0x04, 0x15, 0x40);
        if (err)
                goto error;

        /* EQ Training State Machine Setting, RCO calibration start */
        err = ps8622_set(cl, 0x04, 0x54, 0x10);
        if (err)
                goto error;

        /* Logic, needs more than 10 I2C command */
        /* [4:0] MAX_LANE_COUNT set to max supported lanes */
        err = ps8622_set(cl, 0x01, 0x02, 0x80 | ps8622->max_lane_count);
        if (err)
                goto error;

        /* [4:0] LANE_COUNT_SET set to chosen lane count */
        err = ps8622_set(cl, 0x01, 0x21, 0x80 | ps8622->lane_count);
        if (err)
                goto error;

        err = ps8622_set(cl, 0x00, 0x52, 0x20);
        if (err)
                goto error;

        /* HPD CP toggle enable */
        err = ps8622_set(cl, 0x00, 0xf1, 0x03);
        if (err)
                goto error;

        err = ps8622_set(cl, 0x00, 0x62, 0x41);
        if (err)
                goto error;

        /* Counter number, add 1ms counter delay */
        err = ps8622_set(cl, 0x00, 0xf6, 0x01);
        if (err)
                goto error;

        /* [6]PWM function control by DPCD0040f[7], default is PWM block */
        err = ps8622_set(cl, 0x00, 0x77, 0x06);
        if (err)
                goto error;

        /* 04h Adjust VTotal toleranceto fix the 30Hz no display issue */
        err = ps8622_set(cl, 0x00, 0x4c, 0x04);
        if (err)
                goto error;

        /* DPCD00400='h00, Parade OUI ='h001cf8 */
        err = ps8622_set(cl, 0x01, 0xc0, 0x00);
        if (err)
                goto error;

        /* DPCD00401='h1c */
        err = ps8622_set(cl, 0x01, 0xc1, 0x1c);
        if (err)
                goto error;

        /* DPCD00402='hf8 */
        err = ps8622_set(cl, 0x01, 0xc2, 0xf8);
        if (err)
                goto error;

        /* DPCD403~408 = ASCII code, D2SLV5='h4432534c5635 */
        err = ps8622_set(cl, 0x01, 0xc3, 0x44);
        if (err)
                goto error;

        /* DPCD404 */
        err = ps8622_set(cl, 0x01, 0xc4, 0x32);
        if (err)
                goto error;

        /* DPCD405 */
        err = ps8622_set(cl, 0x01, 0xc5, 0x53);
        if (err)
                goto error;

        /* DPCD406 */
        err = ps8622_set(cl, 0x01, 0xc6, 0x4c);
        if (err)
                goto error;

        /* DPCD407 */
        err = ps8622_set(cl, 0x01, 0xc7, 0x56);
        if (err)
                goto error;

        /* DPCD408 */
        err = ps8622_set(cl, 0x01, 0xc8, 0x35);
        if (err)
                goto error;

        /* DPCD40A, Initial Code major revision '01' */
        err = ps8622_set(cl, 0x01, 0xca, 0x01);
        if (err)
                goto error;

        /* DPCD40B, Initial Code minor revision '05' */
        err = ps8622_set(cl, 0x01, 0xcb, 0x05);
        if (err)
                goto error;


        if (ps8622->bl) {
                /* DPCD720, internal PWM */
                err = ps8622_set(cl, 0x01, 0xa5, 0xa0);
                if (err)
                        goto error;

                /* FFh for 100% brightness, 0h for 0% brightness */
                err = ps8622_set(cl, 0x01, 0xa7,
                                ps8622->bl->props.brightness);
                if (err)
                        goto error;
        } else {
                /* DPCD720, external PWM */
                err = ps8622_set(cl, 0x01, 0xa5, 0x80);
                if (err)
                        goto error;
        }

        /* Set LVDS output as 6bit-VESA mapping, single LVDS channel */
        err = ps8622_set(cl, 0x01, 0xcc, 0x13);
        if (err)
                goto error;

        /* Enable SSC set by register */
        err = ps8622_set(cl, 0x02, 0xb1, 0x20);
        if (err)
                goto error;

        /* Set SSC enabled and +/-1% central spreading */
        err = ps8622_set(cl, 0x04, 0x10, 0x16);
        if (err)
                goto error;

        /* Logic end */
        /* MPU Clock source: LC => RCO */
        err = ps8622_set(cl, 0x04, 0x59, 0x60);
        if (err)
                goto error;

        /* LC -> RCO */
        err = ps8622_set(cl, 0x04, 0x54, 0x14);
        if (err)
                goto error;

        /* HPD high */
        err = ps8622_set(cl, 0x02, 0xa1, 0x91);

error:
        return err ? -EIO : 0;
}

static int ps8622_backlight_update(struct backlight_device *bl)
{
        struct ps8622_bridge *ps8622 = dev_get_drvdata(&bl->dev);
        int ret, brightness = bl->props.brightness;

        if (bl->props.power != FB_BLANK_UNBLANK ||
            bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
                brightness = 0;

        if (!ps8622->enabled)
                return -EINVAL;

        ret = ps8622_set(ps8622->client, 0x01, 0xa7, brightness);

        return ret;
}

static const struct backlight_ops ps8622_backlight_ops = {
        .update_status  = ps8622_backlight_update,
};

static void ps8622_pre_enable(struct drm_bridge *bridge)
{
        struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
        int ret;

        if (ps8622->enabled)
                return;

        gpiod_set_value(ps8622->gpio_rst, 0);

        if (ps8622->v12) {
                ret = regulator_enable(ps8622->v12);
                if (ret)
                        DRM_ERROR("fails to enable ps8622->v12");
        }

        if (drm_panel_prepare(ps8622->panel)) {
                DRM_ERROR("failed to prepare panel\n");
                return;
        }

        gpiod_set_value(ps8622->gpio_slp, 1);

        /*
         * T1 is the range of time that it takes for the power to rise after we
         * enable the lcd/ps8622 fet. T2 is the range of time in which the
         * data sheet specifies we should deassert the reset pin.
         *
         * If it takes T1.max for the power to rise, we need to wait atleast
         * T2.min before deasserting the reset pin. If it takes T1.min for the
         * power to rise, we need to wait at most T2.max before deasserting the
         * reset pin.
         */
        usleep_range(PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US,
                     PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US);

        gpiod_set_value(ps8622->gpio_rst, 1);

        /* wait 20ms after RST high */
        usleep_range(20000, 30000);

        ret = ps8622_send_config(ps8622);
        if (ret) {
                DRM_ERROR("Failed to send config to bridge (%d)\n", ret);
                return;
        }

        ps8622->enabled = true;
}

static void ps8622_enable(struct drm_bridge *bridge)
{
        struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);

        if (drm_panel_enable(ps8622->panel)) {
                DRM_ERROR("failed to enable panel\n");
                return;
        }
}

static void ps8622_disable(struct drm_bridge *bridge)
{
        struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);

        if (drm_panel_disable(ps8622->panel)) {
                DRM_ERROR("failed to disable panel\n");
                return;
        }
        msleep(PS8622_PWMO_END_T12_MS);
}

static void ps8622_post_disable(struct drm_bridge *bridge)
{
        struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);

        if (!ps8622->enabled)
                return;

        ps8622->enabled = false;

        /*
         * This doesn't matter if the regulators are turned off, but something
         * else might keep them on. In that case, we want to assert the slp gpio
         * to lower power.
         */
        gpiod_set_value(ps8622->gpio_slp, 0);

        if (drm_panel_unprepare(ps8622->panel)) {
                DRM_ERROR("failed to unprepare panel\n");
                return;
        }

        if (ps8622->v12)
                regulator_disable(ps8622->v12);

        /*
         * Sleep for at least the amount of time that it takes the power rail to
         * fall to prevent asserting the rst gpio from doing anything.
         */
        usleep_range(PS8622_POWER_FALL_T16_MAX_US,
                     2 * PS8622_POWER_FALL_T16_MAX_US);
        gpiod_set_value(ps8622->gpio_rst, 0);

        msleep(PS8622_POWER_OFF_T17_MS);
}

static int ps8622_get_modes(struct drm_connector *connector)
{
        struct ps8622_bridge *ps8622;

        ps8622 = connector_to_ps8622(connector);

        return drm_panel_get_modes(ps8622->panel);
}

static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
        .get_modes = ps8622_get_modes,
};

static const struct drm_connector_funcs ps8622_connector_funcs = {
        .fill_modes = drm_helper_probe_single_connector_modes,
        .destroy = drm_connector_cleanup,
        .reset = drm_atomic_helper_connector_reset,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};

static int ps8622_attach(struct drm_bridge *bridge)
{
        struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
        int ret;

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

        ps8622->connector.polled = DRM_CONNECTOR_POLL_HPD;
        ret = drm_connector_init(bridge->dev, &ps8622->connector,
                        &ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
        if (ret) {
                DRM_ERROR("Failed to initialize connector with drm\n");
                return ret;
        }
        drm_connector_helper_add(&ps8622->connector,
                                        &ps8622_connector_helper_funcs);
        drm_connector_register(&ps8622->connector);
        drm_mode_connector_attach_encoder(&ps8622->connector,
                                                        bridge->encoder);

        if (ps8622->panel)
                drm_panel_attach(ps8622->panel, &ps8622->connector);

        drm_helper_hpd_irq_event(ps8622->connector.dev);

        return ret;
}

static const struct drm_bridge_funcs ps8622_bridge_funcs = {
        .pre_enable = ps8622_pre_enable,
        .enable = ps8622_enable,
        .disable = ps8622_disable,
        .post_disable = ps8622_post_disable,
        .attach = ps8622_attach,
};

static const struct of_device_id ps8622_devices[] = {
        {.compatible = "parade,ps8622",},
        {.compatible = "parade,ps8625",},
        {}
};
MODULE_DEVICE_TABLE(of, ps8622_devices);

static int ps8622_probe(struct i2c_client *client,
                                        const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct ps8622_bridge *ps8622;
        int ret;

        ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
        if (!ps8622)
                return -ENOMEM;

        ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
        if (ret)
                return ret;

        ps8622->client = client;

        ps8622->v12 = devm_regulator_get(dev, "vdd12");
        if (IS_ERR(ps8622->v12)) {
                dev_info(dev, "no 1.2v regulator found for PS8622\n");
                ps8622->v12 = NULL;
        }

        ps8622->gpio_slp = devm_gpiod_get(dev, "sleep", GPIOD_OUT_HIGH);
        if (IS_ERR(ps8622->gpio_slp)) {
                ret = PTR_ERR(ps8622->gpio_slp);
                dev_err(dev, "cannot get gpio_slp %d\n", ret);
                return ret;
        }

        /*
         * Assert the reset pin high to avoid the bridge being
         * initialized prematurely
         */
        ps8622->gpio_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(ps8622->gpio_rst)) {
                ret = PTR_ERR(ps8622->gpio_rst);
                dev_err(dev, "cannot get gpio_rst %d\n", ret);
                return ret;
        }

        ps8622->max_lane_count = id->driver_data;

        if (of_property_read_u32(dev->of_node, "lane-count",
                                                &ps8622->lane_count)) {
                ps8622->lane_count = ps8622->max_lane_count;
        } else if (ps8622->lane_count > ps8622->max_lane_count) {
                dev_info(dev, "lane-count property is too high,"
                                                "using max_lane_count\n");
                ps8622->lane_count = ps8622->max_lane_count;
        }

        if (!of_find_property(dev->of_node, "use-external-pwm", NULL)) {
                ps8622->bl = backlight_device_register("ps8622-backlight",
                                dev, ps8622, &ps8622_backlight_ops,
                                NULL);
                if (IS_ERR(ps8622->bl)) {
                        DRM_ERROR("failed to register backlight\n");
                        ret = PTR_ERR(ps8622->bl);
                        ps8622->bl = NULL;
                        return ret;
                }
                ps8622->bl->props.max_brightness = PS8622_MAX_BRIGHTNESS;
                ps8622->bl->props.brightness = PS8622_MAX_BRIGHTNESS;
        }

        ps8622->bridge.funcs = &ps8622_bridge_funcs;
        ps8622->bridge.of_node = dev->of_node;
        drm_bridge_add(&ps8622->bridge);

        i2c_set_clientdata(client, ps8622);

        return 0;
}

static int ps8622_remove(struct i2c_client *client)
{
        struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);

        backlight_device_unregister(ps8622->bl);
        drm_bridge_remove(&ps8622->bridge);

        return 0;
}

static const struct i2c_device_id ps8622_i2c_table[] = {
        /* Device type, max_lane_count */
        {"ps8622", 1},
        {"ps8625", 2},
        {},
};
MODULE_DEVICE_TABLE(i2c, ps8622_i2c_table);

static struct i2c_driver ps8622_driver = {
        .id_table       = ps8622_i2c_table,
        .probe          = ps8622_probe,
        .remove         = ps8622_remove,
        .driver         = {
                .name   = "ps8622",
                .of_match_table = ps8622_devices,
        },
};
module_i2c_driver(ps8622_driver);

MODULE_AUTHOR("Vincent Palatin <vpalatin@chromium.org>");
MODULE_DESCRIPTION("Parade ps8622/ps8625 eDP-LVDS converter driver");
MODULE_LICENSE("GPL v2");