/*
 * 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/fb.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/of_graph.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>

#include <drm/drm_panel.h>

#include "drmP.h"
#include "drm_crtc.h"
#include "drm_crtc_helper.h"
#include "drm_atomic_helper.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 enum drm_connector_status ps8622_detect(struct drm_connector *connector,
								bool force)
{
	return connector_status_connected;
}

static void ps8622_connector_destroy(struct drm_connector *connector)
{
	drm_connector_cleanup(connector);
}

static const struct drm_connector_funcs ps8622_connector_funcs = {
	.dpms = drm_atomic_helper_connector_dpms,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.detect = ps8622_detect,
	.destroy = ps8622_connector_destroy,
	.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 device_node *endpoint, *panel_node;
	struct ps8622_bridge *ps8622;
	int ret;

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

	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
	if (endpoint) {
		panel_node = of_graph_get_remote_port_parent(endpoint);
		if (panel_node) {
			ps8622->panel = of_drm_find_panel(panel_node);
			of_node_put(panel_node);
			if (!ps8622->panel)
				return -EPROBE_DEFER;
		}
	}

	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;
	ret = drm_bridge_add(&ps8622->bridge);
	if (ret) {
		DRM_ERROR("Failed to add bridge\n");
		return ret;
	}

	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");