/*
 * Copyright © 2016-2017 Broadcom
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Portions of this file (derived from panel-simple.c) are:
 *
 * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sub license,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/*
 * Raspberry Pi 7" touchscreen panel driver.
 *
 * The 7" touchscreen consists of a DPI LCD panel, a Toshiba
 * TC358762XBG DSI-DPI bridge, and an I2C-connected Atmel ATTINY88-MUR
 * controlling power management, the LCD PWM, and initial register
 * setup of the Tohsiba.
 *
 * This driver controls the TC358762 and ATTINY88, presenting a DSI
 * device with a drm_panel.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/pm.h>

#include <drm/drm_crtc.h>
#include <drm/drm_device.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_panel.h>

#define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"

/* I2C registers of the Atmel microcontroller. */
enum REG_ADDR {
        REG_ID = 0x80,
        REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */
        REG_PORTB,
        REG_PORTC,
        REG_PORTD,
        REG_POWERON,
        REG_PWM,
        REG_DDRA,
        REG_DDRB,
        REG_DDRC,
        REG_DDRD,
        REG_TEST,
        REG_WR_ADDRL,
        REG_WR_ADDRH,
        REG_READH,
        REG_READL,
        REG_WRITEH,
        REG_WRITEL,
        REG_ID2,
};

/* DSI D-PHY Layer Registers */
#define D0W_DPHYCONTTX          0x0004
#define CLW_DPHYCONTRX          0x0020
#define D0W_DPHYCONTRX          0x0024
#define D1W_DPHYCONTRX          0x0028
#define COM_DPHYCONTRX          0x0038
#define CLW_CNTRL               0x0040
#define D0W_CNTRL               0x0044
#define D1W_CNTRL               0x0048
#define DFTMODE_CNTRL           0x0054

/* DSI PPI Layer Registers */
#define PPI_STARTPPI            0x0104
#define PPI_BUSYPPI             0x0108
#define PPI_LINEINITCNT         0x0110
#define PPI_LPTXTIMECNT         0x0114
#define PPI_CLS_ATMR            0x0140
#define PPI_D0S_ATMR            0x0144
#define PPI_D1S_ATMR            0x0148
#define PPI_D0S_CLRSIPOCOUNT    0x0164
#define PPI_D1S_CLRSIPOCOUNT    0x0168
#define CLS_PRE                 0x0180
#define D0S_PRE                 0x0184
#define D1S_PRE                 0x0188
#define CLS_PREP                0x01A0
#define D0S_PREP                0x01A4
#define D1S_PREP                0x01A8
#define CLS_ZERO                0x01C0
#define D0S_ZERO                0x01C4
#define D1S_ZERO                0x01C8
#define PPI_CLRFLG              0x01E0
#define PPI_CLRSIPO             0x01E4
#define HSTIMEOUT               0x01F0
#define HSTIMEOUTENABLE         0x01F4

/* DSI Protocol Layer Registers */
#define DSI_STARTDSI            0x0204
#define DSI_BUSYDSI             0x0208
#define DSI_LANEENABLE          0x0210
# define DSI_LANEENABLE_CLOCK           BIT(0)
# define DSI_LANEENABLE_D0              BIT(1)
# define DSI_LANEENABLE_D1              BIT(2)

#define DSI_LANESTATUS0         0x0214
#define DSI_LANESTATUS1         0x0218
#define DSI_INTSTATUS           0x0220
#define DSI_INTMASK             0x0224
#define DSI_INTCLR              0x0228
#define DSI_LPTXTO              0x0230
#define DSI_MODE                0x0260
#define DSI_PAYLOAD0            0x0268
#define DSI_PAYLOAD1            0x026C
#define DSI_SHORTPKTDAT         0x0270
#define DSI_SHORTPKTREQ         0x0274
#define DSI_BTASTA              0x0278
#define DSI_BTACLR              0x027C

/* DSI General Registers */
#define DSIERRCNT               0x0300
#define DSISIGMOD               0x0304

/* DSI Application Layer Registers */
#define APLCTRL                 0x0400
#define APLSTAT                 0x0404
#define APLERR                  0x0408
#define PWRMOD                  0x040C
#define RDPKTLN                 0x0410
#define PXLFMT                  0x0414
#define MEMWRCMD                0x0418

/* LCDC/DPI Host Registers */
#define LCDCTRL                 0x0420
#define HSR                     0x0424
#define HDISPR                  0x0428
#define VSR                     0x042C
#define VDISPR                  0x0430
#define VFUEN                   0x0434

/* DBI-B Host Registers */
#define DBIBCTRL                0x0440

/* SPI Master Registers */
#define SPICMR                  0x0450
#define SPITCR                  0x0454

/* System Controller Registers */
#define SYSSTAT                 0x0460
#define SYSCTRL                 0x0464
#define SYSPLL1                 0x0468
#define SYSPLL2                 0x046C
#define SYSPLL3                 0x0470
#define SYSPMCTRL               0x047C

/* GPIO Registers */
#define GPIOC                   0x0480
#define GPIOO                   0x0484
#define GPIOI                   0x0488

/* I2C Registers */
#define I2CCLKCTRL              0x0490

/* Chip/Rev Registers */
#define IDREG                   0x04A0

/* Debug Registers */
#define WCMDQUEUE               0x0500
#define RCMDQUEUE               0x0504

struct rpi_touchscreen {
        struct drm_panel base;
        struct mipi_dsi_device *dsi;
        struct i2c_client *i2c;
};

static const struct drm_display_mode rpi_touchscreen_modes[] = {
        {
                /* Modeline comes from the Raspberry Pi firmware, with HFP=1
                 * plugged in and clock re-computed from that.
                 */
                .clock = 25979400 / 1000,
                .hdisplay = 800,
                .hsync_start = 800 + 1,
                .hsync_end = 800 + 1 + 2,
                .htotal = 800 + 1 + 2 + 46,
                .vdisplay = 480,
                .vsync_start = 480 + 7,
                .vsync_end = 480 + 7 + 2,
                .vtotal = 480 + 7 + 2 + 21,
        },
};

static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
{
        return container_of(panel, struct rpi_touchscreen, base);
}

static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
{
        return i2c_smbus_read_byte_data(ts->i2c, reg);
}

static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
                                      u8 reg, u8 val)
{
        int ret;

        ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);
        if (ret)
                dev_err(&ts->i2c->dev, "I2C write failed: %d\n", ret);
}

static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
{
        u8 msg[] = {
                reg,
                reg >> 8,
                val,
                val >> 8,
                val >> 16,
                val >> 24,
        };

        mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg));

        return 0;
}

static int rpi_touchscreen_disable(struct drm_panel *panel)
{
        struct rpi_touchscreen *ts = panel_to_ts(panel);

        rpi_touchscreen_i2c_write(ts, REG_PWM, 0);

        rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
        udelay(1);

        return 0;
}

static int rpi_touchscreen_noop(struct drm_panel *panel)
{
        return 0;
}

static int rpi_touchscreen_prepare(struct drm_panel *panel)
{
        struct rpi_touchscreen *ts = panel_to_ts(panel);
        int i;

        rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
        /* Wait for nPWRDWN to go low to indicate poweron is done. */
        for (i = 0; i < 100; i++) {
                if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
                        break;
        }

        rpi_touchscreen_write(ts, DSI_LANEENABLE,
                              DSI_LANEENABLE_CLOCK |
                              DSI_LANEENABLE_D0);
        rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
        rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
        rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
        rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
        rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);

        rpi_touchscreen_write(ts, SPICMR, 0x00);
        rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
        rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
        msleep(100);

        rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
        rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
        msleep(100);

        return 0;
}

static int rpi_touchscreen_enable(struct drm_panel *panel)
{
        struct rpi_touchscreen *ts = panel_to_ts(panel);

        /* Turn on the backlight. */
        rpi_touchscreen_i2c_write(ts, REG_PWM, 255);

        /* Default to the same orientation as the closed source
         * firmware used for the panel.  Runtime rotation
         * configuration will be supported using VC4's plane
         * orientation bits.
         */
        rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));

        return 0;
}

static int rpi_touchscreen_get_modes(struct drm_panel *panel,
                                     struct drm_connector *connector)
{
        unsigned int i, num = 0;
        static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;

        for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
                const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
                struct drm_display_mode *mode;

                mode = drm_mode_duplicate(connector->dev, m);
                if (!mode) {
                        dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
                                m->hdisplay, m->vdisplay,
                                drm_mode_vrefresh(m));
                        continue;
                }

                mode->type |= DRM_MODE_TYPE_DRIVER;

                if (i == 0)
                        mode->type |= DRM_MODE_TYPE_PREFERRED;

                drm_mode_set_name(mode);

                drm_mode_probed_add(connector, mode);
                num++;
        }

        connector->display_info.bpc = 8;
        connector->display_info.width_mm = 154;
        connector->display_info.height_mm = 86;
        drm_display_info_set_bus_formats(&connector->display_info,
                                         &bus_format, 1);

        return num;
}

static const struct drm_panel_funcs rpi_touchscreen_funcs = {
        .disable = rpi_touchscreen_disable,
        .unprepare = rpi_touchscreen_noop,
        .prepare = rpi_touchscreen_prepare,
        .enable = rpi_touchscreen_enable,
        .get_modes = rpi_touchscreen_get_modes,
};

static int rpi_touchscreen_probe(struct i2c_client *i2c)
{
        struct device *dev = &i2c->dev;
        struct rpi_touchscreen *ts;
        struct device_node *endpoint, *dsi_host_node;
        struct mipi_dsi_host *host;
        int ver;
        struct mipi_dsi_device_info info = {
                .type = RPI_DSI_DRIVER_NAME,
                .channel = 0,
                .node = NULL,
        };

        ts = devm_drm_panel_alloc(dev, __typeof(*ts), base,
                                  &rpi_touchscreen_funcs,
                                  DRM_MODE_CONNECTOR_DSI);

        if (IS_ERR(ts))
                return PTR_ERR(ts);

        i2c_set_clientdata(i2c, ts);

        ts->i2c = i2c;

        ver = rpi_touchscreen_i2c_read(ts, REG_ID);
        if (ver < 0) {
                dev_err(dev, "Atmel I2C read failed: %d\n", ver);
                return -ENODEV;
        }

        switch (ver) {
        case 0xde: /* ver 1 */
        case 0xc3: /* ver 2 */
                break;
        default:
                dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
                return -ENODEV;
        }

        /* Turn off at boot, so we can cleanly sequence powering on. */
        rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);

        /* Look up the DSI host.  It needs to probe before we do. */
        endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
        if (!endpoint)
                return -ENODEV;

        dsi_host_node = of_graph_get_remote_port_parent(endpoint);
        if (!dsi_host_node)
                goto error;

        host = of_find_mipi_dsi_host_by_node(dsi_host_node);
        of_node_put(dsi_host_node);
        if (!host) {
                of_node_put(endpoint);
                return -EPROBE_DEFER;
        }

        info.node = of_graph_get_remote_port(endpoint);
        if (!info.node)
                goto error;

        of_node_put(endpoint);

        ts->dsi = mipi_dsi_device_register_full(host, &info);
        if (IS_ERR(ts->dsi)) {
                dev_err(dev, "DSI device registration failed: %ld\n",
                        PTR_ERR(ts->dsi));
                return PTR_ERR(ts->dsi);
        }

        /* This appears last, as it's what will unblock the DSI host
         * driver's component bind function.
         */
        drm_panel_add(&ts->base);

        return 0;

error:
        of_node_put(endpoint);
        return -ENODEV;
}

static void rpi_touchscreen_remove(struct i2c_client *i2c)
{
        struct rpi_touchscreen *ts = i2c_get_clientdata(i2c);

        mipi_dsi_detach(ts->dsi);

        drm_panel_remove(&ts->base);

        mipi_dsi_device_unregister(ts->dsi);
}

static int rpi_touchscreen_dsi_probe(struct mipi_dsi_device *dsi)
{
        int ret;

        dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |
                           MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
                           MIPI_DSI_MODE_LPM);
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->lanes = 1;

        ret = mipi_dsi_attach(dsi);

        if (ret)
                dev_err(&dsi->dev, "failed to attach dsi to host: %d\n", ret);

        return ret;
}

static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {
        .driver.name = RPI_DSI_DRIVER_NAME,
        .probe = rpi_touchscreen_dsi_probe,
};

static const struct of_device_id rpi_touchscreen_of_ids[] = {
        { .compatible = "raspberrypi,7inch-touchscreen-panel" },
        { } /* sentinel */
};
MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);

static struct i2c_driver rpi_touchscreen_driver = {
        .driver = {
                .name = "rpi_touchscreen",
                .of_match_table = rpi_touchscreen_of_ids,
        },
        .probe = rpi_touchscreen_probe,
        .remove = rpi_touchscreen_remove,
};

static int __init rpi_touchscreen_init(void)
{
        mipi_dsi_driver_register(&rpi_touchscreen_dsi_driver);
        return i2c_add_driver(&rpi_touchscreen_driver);
}
module_init(rpi_touchscreen_init);

static void __exit rpi_touchscreen_exit(void)
{
        i2c_del_driver(&rpi_touchscreen_driver);
        mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);
}
module_exit(rpi_touchscreen_exit);

MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");
MODULE_LICENSE("GPL v2");