// SPDX-License-Identifier: GPL-2.0+
/*
 * This is a driver for the keyboard, touchpad and USB port of the
 * keyboard dock for the Asus TF103C 2-in-1 tablet.
 *
 * This keyboard dock has its own I2C attached embedded controller
 * and the keyboard and touchpad are also connected over I2C,
 * instead of using the usual USB connection. This means that the
 * keyboard dock requires this special driver to function.
 *
 * Copyright (C) 2021 Hans de Goede <hdegoede@redhat.com>
 */

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/machine.h>
#include <linux/hid.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/mod_devicetable.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/workqueue.h>
#include <linux/unaligned.h>

static bool fnlock;
module_param(fnlock, bool, 0644);
MODULE_PARM_DESC(fnlock,
                 "By default the kbd toprow sends multimedia key presses. AltGr "
                 "can be pressed to change this to F1-F12. Set this to 1 to "
                 "change the default. Press AltGr + Esc to toggle at runtime.");

#define TF103C_DOCK_DEV_NAME                            "NPCE69A:00"

#define TF103C_DOCK_HPD_DEBOUNCE                        msecs_to_jiffies(20)

/*** Touchpad I2C device defines ***/
#define TF103C_DOCK_TP_ADDR                             0x15

/*** Keyboard I2C device defines **A*/
#define TF103C_DOCK_KBD_ADDR                            0x16

#define TF103C_DOCK_KBD_DATA_REG                        0x73
#define TF103C_DOCK_KBD_DATA_MIN_LENGTH                 4
#define TF103C_DOCK_KBD_DATA_MAX_LENGTH                 11
#define TF103C_DOCK_KBD_DATA_MODIFIERS                  3
#define TF103C_DOCK_KBD_DATA_KEYS                       5
#define TF103C_DOCK_KBD_CMD_REG                         0x75

#define TF103C_DOCK_KBD_CMD_ENABLE                      0x0800

/*** EC innterrupt data I2C device defines ***/
#define TF103C_DOCK_INTR_ADDR                           0x19
#define TF103C_DOCK_INTR_DATA_REG                       0x6a

#define TF103C_DOCK_INTR_DATA1_OBF_MASK                 0x01
#define TF103C_DOCK_INTR_DATA1_KEY_MASK                 0x04
#define TF103C_DOCK_INTR_DATA1_KBC_MASK                 0x08
#define TF103C_DOCK_INTR_DATA1_AUX_MASK                 0x20
#define TF103C_DOCK_INTR_DATA1_SCI_MASK                 0x40
#define TF103C_DOCK_INTR_DATA1_SMI_MASK                 0x80
/* Special values for the OOB data on kbd_client / tp_client */
#define TF103C_DOCK_INTR_DATA1_OOB_VALUE                0xc1
#define TF103C_DOCK_INTR_DATA2_OOB_VALUE                0x04

#define TF103C_DOCK_SMI_AC_EVENT                        0x31
#define TF103C_DOCK_SMI_HANDSHAKING                     0x50
#define TF103C_DOCK_SMI_EC_WAKEUP                       0x53
#define TF103C_DOCK_SMI_BOOTBLOCK_RESET                 0x5e
#define TF103C_DOCK_SMI_WATCHDOG_RESET                  0x5f
#define TF103C_DOCK_SMI_ADAPTER_CHANGE                  0x60
#define TF103C_DOCK_SMI_DOCK_INSERT                     0x61
#define TF103C_DOCK_SMI_DOCK_REMOVE                     0x62
#define TF103C_DOCK_SMI_PAD_BL_CHANGE                   0x63
#define TF103C_DOCK_SMI_HID_STATUS_CHANGED              0x64
#define TF103C_DOCK_SMI_HID_WAKEUP                      0x65
#define TF103C_DOCK_SMI_S3                              0x83
#define TF103C_DOCK_SMI_S5                              0x85
#define TF103C_DOCK_SMI_NOTIFY_SHUTDOWN                 0x90
#define TF103C_DOCK_SMI_RESUME                          0x91

/*** EC (dockram) I2C device defines ***/
#define TF103C_DOCK_EC_ADDR                             0x1b

#define TF103C_DOCK_EC_CMD_REG                          0x0a
#define TF103C_DOCK_EC_CMD_LEN                          9

enum {
        TF103C_DOCK_FLAG_HID_OPEN,
};

struct tf103c_dock_data {
        struct delayed_work hpd_work;
        struct irq_chip tp_irqchip;
        struct irq_domain *tp_irq_domain;
        struct i2c_client *ec_client;
        struct i2c_client *intr_client;
        struct i2c_client *kbd_client;
        struct i2c_client *tp_client;
        struct gpio_desc *pwr_en;
        struct gpio_desc *irq_gpio;
        struct gpio_desc *hpd_gpio;
        struct input_dev *input;
        struct hid_device *hid;
        unsigned long flags;
        int board_rev;
        int irq;
        int hpd_irq;
        int tp_irq;
        int last_press_0x13;
        int last_press_0x14;
        bool enabled;
        bool tp_enabled;
        bool altgr_pressed;
        bool esc_pressed;
        bool filter_esc;
        u8 kbd_buf[TF103C_DOCK_KBD_DATA_MAX_LENGTH];
};

static struct gpiod_lookup_table tf103c_dock_gpios = {
        .dev_id = "i2c-" TF103C_DOCK_DEV_NAME,
        .table = {
                GPIO_LOOKUP("INT33FC:00",      55, "dock_pwr_en", GPIO_ACTIVE_HIGH),
                GPIO_LOOKUP("INT33FC:02",       1, "dock_irq", GPIO_ACTIVE_HIGH),
                GPIO_LOOKUP("INT33FC:02",      29, "dock_hpd", GPIO_ACTIVE_HIGH),
                GPIO_LOOKUP("gpio_crystalcove", 2, "board_rev", GPIO_ACTIVE_HIGH),
                {}
        },
};

/* Byte 0 is the length of the rest of the packet */
static const u8 tf103c_dock_enable_cmd[9] = { 8, 0x20, 0, 0, 0, 0, 0x20, 0, 0 };
static const u8 tf103c_dock_usb_enable_cmd[9] = { 8, 0, 0, 0, 0, 0, 0, 0x40, 0 };
static const u8 tf103c_dock_suspend_cmd[9] = { 8, 0, 0x20, 0, 0, 0x22, 0, 0, 0 };

/*** keyboard related code ***/

static u8 tf103c_dock_kbd_hid_desc[] = {
        0x05, 0x01,         /*  Usage Page (Desktop),               */
        0x09, 0x06,         /*  Usage (Keyboard),                   */
        0xA1, 0x01,         /*  Collection (Application),           */
        0x85, 0x11,         /*      Report ID (17),                 */
        0x95, 0x08,         /*      Report Count (8),               */
        0x75, 0x01,         /*      Report Size (1),                */
        0x15, 0x00,         /*      Logical Minimum (0),            */
        0x25, 0x01,         /*      Logical Maximum (1),            */
        0x05, 0x07,         /*      Usage Page (Keyboard),          */
        0x19, 0xE0,         /*      Usage Minimum (KB Leftcontrol), */
        0x29, 0xE7,         /*      Usage Maximum (KB Right GUI),   */
        0x81, 0x02,         /*      Input (Variable),               */
        0x95, 0x01,         /*      Report Count (1),               */
        0x75, 0x08,         /*      Report Size (8),                */
        0x81, 0x01,         /*      Input (Constant),               */
        0x95, 0x06,         /*      Report Count (6),               */
        0x75, 0x08,         /*      Report Size (8),                */
        0x15, 0x00,         /*      Logical Minimum (0),            */
        0x26, 0xFF, 0x00,   /*      Logical Maximum (255),          */
        0x05, 0x07,         /*      Usage Page (Keyboard),          */
        0x19, 0x00,         /*      Usage Minimum (None),           */
        0x2A, 0xFF, 0x00,   /*      Usage Maximum (FFh),            */
        0x81, 0x00,         /*      Input,                          */
        0xC0                /*  End Collection                      */
};

static int tf103c_dock_kbd_read(struct tf103c_dock_data *dock)
{
        struct i2c_client *client = dock->kbd_client;
        struct device *dev = &dock->ec_client->dev;
        struct i2c_msg msgs[2];
        u8 reg[2];
        int ret;

        reg[0] = TF103C_DOCK_KBD_DATA_REG & 0xff;
        reg[1] = TF103C_DOCK_KBD_DATA_REG >> 8;

        msgs[0].addr = client->addr;
        msgs[0].flags = 0;
        msgs[0].len = sizeof(reg);
        msgs[0].buf = reg;

        msgs[1].addr = client->addr;
        msgs[1].flags = I2C_M_RD;
        msgs[1].len = TF103C_DOCK_KBD_DATA_MAX_LENGTH;
        msgs[1].buf = dock->kbd_buf;

        ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
        if (ret != ARRAY_SIZE(msgs)) {
                dev_err(dev, "error %d reading kbd data\n", ret);
                return -EIO;
        }

        return 0;
}

static void tf103c_dock_kbd_write(struct tf103c_dock_data *dock, u16 cmd)
{
        struct device *dev = &dock->ec_client->dev;
        u8 buf[4];
        int ret;

        put_unaligned_le16(TF103C_DOCK_KBD_CMD_REG, &buf[0]);
        put_unaligned_le16(cmd, &buf[2]);

        ret = i2c_master_send(dock->kbd_client, buf, sizeof(buf));
        if (ret != sizeof(buf))
                dev_err(dev, "error %d writing kbd cmd\n", ret);
}

/* HID ll_driver functions for forwarding input-reports from the kbd_client */
static int tf103c_dock_hid_parse(struct hid_device *hid)
{
        return hid_parse_report(hid, tf103c_dock_kbd_hid_desc,
                                sizeof(tf103c_dock_kbd_hid_desc));
}

static int tf103c_dock_hid_start(struct hid_device *hid)
{
        return 0;
}

static void tf103c_dock_hid_stop(struct hid_device *hid)
{
        hid->claimed = 0;
}

static int tf103c_dock_hid_open(struct hid_device *hid)
{
        struct tf103c_dock_data *dock = hid->driver_data;

        set_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags);
        return 0;
}

static void tf103c_dock_hid_close(struct hid_device *hid)
{
        struct tf103c_dock_data *dock = hid->driver_data;

        clear_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags);
}

/* Mandatory, but not used */
static int tf103c_dock_hid_raw_request(struct hid_device *hid, u8 reportnum,
                                       u8 *buf, size_t len, u8 rtype, int reqtype)
{
        return 0;
}

static const struct hid_ll_driver tf103c_dock_hid_ll_driver = {
        .parse = tf103c_dock_hid_parse,
        .start = tf103c_dock_hid_start,
        .stop = tf103c_dock_hid_stop,
        .open = tf103c_dock_hid_open,
        .close = tf103c_dock_hid_close,
        .raw_request = tf103c_dock_hid_raw_request,
};

static const int tf103c_dock_toprow_codes[13][2] = {
        /* Normal,            AltGr pressed */
        { KEY_POWER,          KEY_F1 },
        { KEY_RFKILL,         KEY_F2 },
        { KEY_F21,            KEY_F3 }, /* Touchpad toggle, userspace expects F21 */
        { KEY_BRIGHTNESSDOWN, KEY_F4 },
        { KEY_BRIGHTNESSUP,   KEY_F5 },
        { KEY_CAMERA,         KEY_F6 },
        { KEY_CONFIG,         KEY_F7 },
        { KEY_PREVIOUSSONG,   KEY_F8 },
        { KEY_PLAYPAUSE,      KEY_F9 },
        { KEY_NEXTSONG,       KEY_F10 },
        { KEY_MUTE,           KEY_F11 },
        { KEY_VOLUMEDOWN,     KEY_F12 },
        { KEY_VOLUMEUP,       KEY_SYSRQ },
};

static void tf103c_dock_report_toprow_kbd_hook(struct tf103c_dock_data *dock)
{
        u8 *esc, *buf = dock->kbd_buf;
        int size;

        /*
         * Stop AltGr reports from getting reported on the "Asus TF103C Dock
         * Keyboard" input_dev, since this gets used as "Fn" key for the toprow
         * keys. Instead we report this on the "Asus TF103C Dock Top Row Keys"
         * input_dev, when not used to modify the toprow keys.
         */
        dock->altgr_pressed = buf[TF103C_DOCK_KBD_DATA_MODIFIERS] & 0x40;
        buf[TF103C_DOCK_KBD_DATA_MODIFIERS] &= ~0x40;

        input_report_key(dock->input, KEY_RIGHTALT, dock->altgr_pressed);
        input_sync(dock->input);

        /* Toggle fnlock on AltGr + Esc press */
        buf = buf + TF103C_DOCK_KBD_DATA_KEYS;
        size = TF103C_DOCK_KBD_DATA_MAX_LENGTH - TF103C_DOCK_KBD_DATA_KEYS;
        esc = memchr(buf, 0x29, size);
        if (!dock->esc_pressed && esc) {
                if (dock->altgr_pressed) {
                        fnlock = !fnlock;
                        dock->filter_esc = true;
                }
        }
        if (esc && dock->filter_esc)
                *esc = 0;
        else
                dock->filter_esc = false;

        dock->esc_pressed = esc != NULL;
}

static void tf103c_dock_toprow_press(struct tf103c_dock_data *dock, int key_code)
{
        /*
         * Release AltGr before reporting the toprow key, so that userspace
         * sees e.g. just KEY_SUSPEND and not AltGr + KEY_SUSPEND.
         */
        if (dock->altgr_pressed) {
                input_report_key(dock->input, KEY_RIGHTALT, false);
                input_sync(dock->input);
        }

        input_report_key(dock->input, key_code, true);
        input_sync(dock->input);
}

static void tf103c_dock_toprow_release(struct tf103c_dock_data *dock, int key_code)
{
        input_report_key(dock->input, key_code, false);
        input_sync(dock->input);

        if (dock->altgr_pressed) {
                input_report_key(dock->input, KEY_RIGHTALT, true);
                input_sync(dock->input);
        }
}

static void tf103c_dock_toprow_event(struct tf103c_dock_data *dock,
                                            int toprow_index, int *last_press)
{
        int key_code, fn = dock->altgr_pressed ^ fnlock;

        if (last_press && *last_press) {
                tf103c_dock_toprow_release(dock, *last_press);
                *last_press = 0;
        }

        if (toprow_index < 0)
                return;

        key_code = tf103c_dock_toprow_codes[toprow_index][fn];
        tf103c_dock_toprow_press(dock, key_code);

        if (last_press)
                *last_press = key_code;
        else
                tf103c_dock_toprow_release(dock, key_code);
}

/*
 * The keyboard sends what appears to be standard I2C-HID input-reports,
 * except that a 16 bit register address of where the I2C-HID format
 * input-reports are stored must be send before reading it in a single
 * (I2C repeated-start) I2C transaction.
 *
 * Its unknown how to get the HID descriptors but they are easy to reconstruct:
 *
 * Input report id 0x11 is 8 bytes long and contain standard USB HID intf-class,
 * Boot Interface Subclass reports.
 * Input report id 0x13 is 2 bytes long and sends Consumer Control events
 * Input report id 0x14 is 1 byte long and sends System Control events
 *
 * However the top row keys (where a normal keyboard has F1-F12 + Print-Screen)
 * are a mess, using a mix of the 0x13 and 0x14 input reports as well as EC SCI
 * events; and these need special handling to allow actually sending F1-F12,
 * since the Fn key on the keyboard only works on the cursor keys and the top
 * row keys always send their special "Multimedia hotkey" codes.
 *
 * So only forward the 0x11 reports to HID and handle the top-row keys here.
 */
static void tf103c_dock_kbd_interrupt(struct tf103c_dock_data *dock)
{
        struct device *dev = &dock->ec_client->dev;
        u8 *buf = dock->kbd_buf;
        int size;

        if (tf103c_dock_kbd_read(dock))
                return;

        size = buf[0] | buf[1] << 8;
        if (size < TF103C_DOCK_KBD_DATA_MIN_LENGTH ||
            size > TF103C_DOCK_KBD_DATA_MAX_LENGTH) {
                dev_err(dev, "error reported kbd pkt size %d is out of range %d-%d\n", size,
                        TF103C_DOCK_KBD_DATA_MIN_LENGTH,
                        TF103C_DOCK_KBD_DATA_MAX_LENGTH);
                return;
        }

        switch (buf[2]) {
        case 0x11:
                if (size != 11)
                        break;

                tf103c_dock_report_toprow_kbd_hook(dock);

                if (test_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags))
                        hid_input_report(dock->hid, HID_INPUT_REPORT, buf + 2, size - 2, 1);
                return;
        case 0x13:
                if (size != 5)
                        break;

                switch (buf[3] | buf[4] << 8) {
                case 0:
                        tf103c_dock_toprow_event(dock, -1, &dock->last_press_0x13);
                        return;
                case 0x70:
                        tf103c_dock_toprow_event(dock, 3, &dock->last_press_0x13);
                        return;
                case 0x6f:
                        tf103c_dock_toprow_event(dock, 4, &dock->last_press_0x13);
                        return;
                case 0xb6:
                        tf103c_dock_toprow_event(dock, 7, &dock->last_press_0x13);
                        return;
                case 0xcd:
                        tf103c_dock_toprow_event(dock, 8, &dock->last_press_0x13);
                        return;
                case 0xb5:
                        tf103c_dock_toprow_event(dock, 9, &dock->last_press_0x13);
                        return;
                case 0xe2:
                        tf103c_dock_toprow_event(dock, 10, &dock->last_press_0x13);
                        return;
                case 0xea:
                        tf103c_dock_toprow_event(dock, 11, &dock->last_press_0x13);
                        return;
                case 0xe9:
                        tf103c_dock_toprow_event(dock, 12, &dock->last_press_0x13);
                        return;
                }
                break;
        case 0x14:
                if (size != 4)
                        break;

                switch (buf[3]) {
                case 0:
                        tf103c_dock_toprow_event(dock, -1, &dock->last_press_0x14);
                        return;
                case 1:
                        tf103c_dock_toprow_event(dock, 0, &dock->last_press_0x14);
                        return;
                }
                break;
        }

        dev_warn(dev, "warning unknown kbd data: %*ph\n", size, buf);
}

/*** touchpad related code ***/

static const struct property_entry tf103c_dock_touchpad_props[] = {
        PROPERTY_ENTRY_BOOL("elan,clickpad"),
        { }
};

static const struct software_node tf103c_dock_touchpad_sw_node = {
        .properties = tf103c_dock_touchpad_props,
};

/*
 * tf103c_enable_touchpad() is only called from the threaded interrupt handler
 * and tf103c_disable_touchpad() is only called after the irq is disabled,
 * so no locking is necessary.
 */
static void tf103c_dock_enable_touchpad(struct tf103c_dock_data *dock)
{
        struct i2c_board_info board_info = { };
        struct device *dev = &dock->ec_client->dev;
        int ret;

        if (dock->tp_enabled) {
                /* Happens after resume, the tp needs to be reinitialized */
                ret = device_reprobe(&dock->tp_client->dev);
                if (ret)
                        dev_err_probe(dev, ret, "reprobing tp-client\n");
                return;
        }

        strscpy(board_info.type, "elan_i2c");
        board_info.addr = TF103C_DOCK_TP_ADDR;
        board_info.dev_name = TF103C_DOCK_DEV_NAME "-tp";
        board_info.irq = dock->tp_irq;
        board_info.swnode = &tf103c_dock_touchpad_sw_node;

        dock->tp_client = i2c_new_client_device(dock->ec_client->adapter, &board_info);
        if (IS_ERR(dock->tp_client)) {
                dev_err(dev, "error %ld creating tp client\n", PTR_ERR(dock->tp_client));
                return;
        }

        dock->tp_enabled = true;
}

static void tf103c_dock_disable_touchpad(struct tf103c_dock_data *dock)
{
        if (!dock->tp_enabled)
                return;

        i2c_unregister_device(dock->tp_client);

        dock->tp_enabled = false;
}

/*** interrupt handling code ***/
static void tf103c_dock_ec_cmd(struct tf103c_dock_data *dock, const u8 *cmd)
{
        struct device *dev = &dock->ec_client->dev;
        int ret;

        ret = i2c_smbus_write_i2c_block_data(dock->ec_client, TF103C_DOCK_EC_CMD_REG,
                                             TF103C_DOCK_EC_CMD_LEN, cmd);
        if (ret)
                dev_err(dev, "error %d sending %*ph cmd\n", ret,
                        TF103C_DOCK_EC_CMD_LEN, cmd);
}

static void tf103c_dock_sci(struct tf103c_dock_data *dock, u8 val)
{
        struct device *dev = &dock->ec_client->dev;

        switch (val) {
        case 2:
                tf103c_dock_toprow_event(dock, 1, NULL);
                return;
        case 4:
                tf103c_dock_toprow_event(dock, 2, NULL);
                return;
        case 8:
                tf103c_dock_toprow_event(dock, 5, NULL);
                return;
        case 17:
                tf103c_dock_toprow_event(dock, 6, NULL);
                return;
        }

        dev_warn(dev, "warning unknown SCI value: 0x%02x\n", val);
}

static void tf103c_dock_smi(struct tf103c_dock_data *dock, u8 val)
{
        struct device *dev = &dock->ec_client->dev;

        switch (val) {
        case TF103C_DOCK_SMI_EC_WAKEUP:
                tf103c_dock_ec_cmd(dock, tf103c_dock_enable_cmd);
                tf103c_dock_ec_cmd(dock, tf103c_dock_usb_enable_cmd);
                tf103c_dock_kbd_write(dock, TF103C_DOCK_KBD_CMD_ENABLE);
                break;
        case TF103C_DOCK_SMI_PAD_BL_CHANGE:
                /* There is no backlight, but the EC still sends this */
                break;
        case TF103C_DOCK_SMI_HID_STATUS_CHANGED:
                tf103c_dock_enable_touchpad(dock);
                break;
        default:
                dev_warn(dev, "warning unknown SMI value: 0x%02x\n", val);
                break;
        }
}

static irqreturn_t tf103c_dock_irq(int irq, void *data)
{
        struct tf103c_dock_data *dock = data;
        struct device *dev = &dock->ec_client->dev;
        u8 intr_data[8];
        int ret;

        ret = i2c_smbus_read_i2c_block_data(dock->intr_client, TF103C_DOCK_INTR_DATA_REG,
                                            sizeof(intr_data), intr_data);
        if (ret != sizeof(intr_data)) {
                dev_err(dev, "error %d reading intr data\n", ret);
                return IRQ_NONE;
        }

        if (!(intr_data[1] & TF103C_DOCK_INTR_DATA1_OBF_MASK))
                return IRQ_NONE;

        /* intr_data[0] is the length of the rest of the packet */
        if (intr_data[0] == 3 && intr_data[1] == TF103C_DOCK_INTR_DATA1_OOB_VALUE &&
                                 intr_data[2] == TF103C_DOCK_INTR_DATA2_OOB_VALUE) {
                /* intr_data[3] seems to contain a HID input report id */
                switch (intr_data[3]) {
                case 0x01:
                        handle_nested_irq(dock->tp_irq);
                        break;
                case 0x11:
                case 0x13:
                case 0x14:
                        tf103c_dock_kbd_interrupt(dock);
                        break;
                default:
                        dev_warn(dev, "warning unknown intr_data[3]: 0x%02x\n", intr_data[3]);
                        break;
                }
                return IRQ_HANDLED;
        }

        if (intr_data[1] & TF103C_DOCK_INTR_DATA1_SCI_MASK) {
                tf103c_dock_sci(dock, intr_data[2]);
                return IRQ_HANDLED;
        }

        if (intr_data[1] & TF103C_DOCK_INTR_DATA1_SMI_MASK) {
                tf103c_dock_smi(dock, intr_data[2]);
                return IRQ_HANDLED;
        }

        dev_warn(dev, "warning unknown intr data: %*ph\n", 8, intr_data);
        return IRQ_NONE;
}

/*
 * tf103c_dock_[dis|en]able only run from hpd_work or at times when
 * hpd_work cannot run (hpd_irq disabled), so no locking is necessary.
 */
static void tf103c_dock_enable(struct tf103c_dock_data *dock)
{
        if (dock->enabled)
                return;

        if (dock->board_rev != 2)
                gpiod_set_value(dock->pwr_en, 1);

        msleep(500);
        enable_irq(dock->irq);

        dock->enabled = true;
}

static void tf103c_dock_disable(struct tf103c_dock_data *dock)
{
        if (!dock->enabled)
                return;

        disable_irq(dock->irq);
        tf103c_dock_disable_touchpad(dock);
        if (dock->board_rev != 2)
                gpiod_set_value(dock->pwr_en, 0);

        dock->enabled = false;
}

static void tf103c_dock_hpd_work(struct work_struct *work)
{
        struct tf103c_dock_data *dock =
                container_of(work, struct tf103c_dock_data, hpd_work.work);

        if (gpiod_get_value(dock->hpd_gpio))
                tf103c_dock_enable(dock);
        else
                tf103c_dock_disable(dock);
}

static irqreturn_t tf103c_dock_hpd_irq(int irq, void *data)
{
        struct tf103c_dock_data *dock = data;

        mod_delayed_work(system_long_wq, &dock->hpd_work, TF103C_DOCK_HPD_DEBOUNCE);
        return IRQ_HANDLED;
}

static void tf103c_dock_start_hpd(struct tf103c_dock_data *dock)
{
        enable_irq(dock->hpd_irq);
        /* Sync current HPD status */
        queue_delayed_work(system_long_wq, &dock->hpd_work, TF103C_DOCK_HPD_DEBOUNCE);
}

static void tf103c_dock_stop_hpd(struct tf103c_dock_data *dock)
{
        disable_irq(dock->hpd_irq);
        cancel_delayed_work_sync(&dock->hpd_work);
}

/*** probe ***/

static const struct dmi_system_id tf103c_dock_dmi_ids[] = {
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "TF103C"),
                },
        },
        { }
};

static void tf103c_dock_non_devm_cleanup(void *data)
{
        struct tf103c_dock_data *dock = data;

        if (dock->tp_irq_domain)
                irq_domain_remove(dock->tp_irq_domain);

        if (!IS_ERR_OR_NULL(dock->hid))
                hid_destroy_device(dock->hid);

        i2c_unregister_device(dock->kbd_client);
        i2c_unregister_device(dock->intr_client);
        gpiod_remove_lookup_table(&tf103c_dock_gpios);
}

static int tf103c_dock_probe(struct i2c_client *client)
{
        struct i2c_board_info board_info = { };
        struct device *dev = &client->dev;
        struct gpio_desc *board_rev_gpio;
        struct tf103c_dock_data *dock;
        enum gpiod_flags flags;
        int i, ret;

        /* GPIOs are hardcoded for the Asus TF103C, don't bind on other devs */
        if (!dmi_check_system(tf103c_dock_dmi_ids))
                return -ENODEV;

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

        INIT_DELAYED_WORK(&dock->hpd_work, tf103c_dock_hpd_work);

        /* 1. Get GPIOs and their IRQs */
        gpiod_add_lookup_table(&tf103c_dock_gpios);

        ret = devm_add_action_or_reset(dev, tf103c_dock_non_devm_cleanup, dock);
        if (ret)
                return ret;

        /*
         * The pin is configured as input by default, use ASIS because otherwise
         * the gpio-crystalcove.c switches off the internal pull-down replacing
         * it with a pull-up.
         */
        board_rev_gpio = gpiod_get(dev, "board_rev", GPIOD_ASIS);
        if (IS_ERR(board_rev_gpio))
                return dev_err_probe(dev, PTR_ERR(board_rev_gpio), "requesting board_rev GPIO\n");
        dock->board_rev = gpiod_get_value_cansleep(board_rev_gpio) + 1;
        gpiod_put(board_rev_gpio);

        /*
         * The Android driver drives the dock-pwr-en pin high at probe for
         * revision 2 boards and then never touches it again?
         * This code has only been tested on a revision 1 board, so for now
         * just mimick what Android does on revision 2 boards.
         */
        flags = (dock->board_rev == 2) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
        dock->pwr_en = devm_gpiod_get(dev, "dock_pwr_en", flags);
        if (IS_ERR(dock->pwr_en))
                return dev_err_probe(dev, PTR_ERR(dock->pwr_en), "requesting pwr_en GPIO\n");

        dock->irq_gpio = devm_gpiod_get(dev, "dock_irq", GPIOD_IN);
        if (IS_ERR(dock->irq_gpio))
                return dev_err_probe(dev, PTR_ERR(dock->irq_gpio), "requesting IRQ GPIO\n");

        dock->irq = gpiod_to_irq(dock->irq_gpio);
        if (dock->irq < 0)
                return dev_err_probe(dev, dock->irq, "getting dock IRQ");

        ret = devm_request_threaded_irq(dev, dock->irq, NULL, tf103c_dock_irq,
                                        IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_NO_AUTOEN,
                                        "dock_irq", dock);
        if (ret)
                return dev_err_probe(dev, ret, "requesting dock IRQ");

        dock->hpd_gpio = devm_gpiod_get(dev, "dock_hpd", GPIOD_IN);
        if (IS_ERR(dock->hpd_gpio))
                return dev_err_probe(dev, PTR_ERR(dock->hpd_gpio), "requesting HPD GPIO\n");

        dock->hpd_irq = gpiod_to_irq(dock->hpd_gpio);
        if (dock->hpd_irq < 0)
                return dev_err_probe(dev, dock->hpd_irq, "getting HPD IRQ");

        ret = devm_request_irq(dev, dock->hpd_irq, tf103c_dock_hpd_irq,
                               IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN,
                               "dock_hpd", dock);
        if (ret)
                return ret;

        /*
         * 2. Create I2C clients. The dock uses 4 different i2c addresses,
         * the ACPI NPCE69A node being probed points to the EC address.
         */
        dock->ec_client = client;

        strscpy(board_info.type, "tf103c-dock-intr");
        board_info.addr = TF103C_DOCK_INTR_ADDR;
        board_info.dev_name = TF103C_DOCK_DEV_NAME "-intr";

        dock->intr_client = i2c_new_client_device(client->adapter, &board_info);
        if (IS_ERR(dock->intr_client))
                return dev_err_probe(dev, PTR_ERR(dock->intr_client), "creating intr client\n");

        strscpy(board_info.type, "tf103c-dock-kbd");
        board_info.addr = TF103C_DOCK_KBD_ADDR;
        board_info.dev_name = TF103C_DOCK_DEV_NAME "-kbd";

        dock->kbd_client = i2c_new_client_device(client->adapter, &board_info);
        if (IS_ERR(dock->kbd_client))
                return dev_err_probe(dev, PTR_ERR(dock->kbd_client), "creating kbd client\n");

        /* 3. Create input_dev for the top row of the keyboard */
        dock->input = devm_input_allocate_device(dev);
        if (!dock->input)
                return -ENOMEM;

        dock->input->name = "Asus TF103C Dock Top Row Keys";
        dock->input->phys = dev_name(dev);
        dock->input->dev.parent = dev;
        dock->input->id.bustype = BUS_I2C;
        dock->input->id.vendor = /* USB_VENDOR_ID_ASUSTEK */
        dock->input->id.product = /* From TF-103-C */
        dock->input->id.version = 0x0100;  /* 1.0 */

        for (i = 0; i < ARRAY_SIZE(tf103c_dock_toprow_codes); i++) {
                input_set_capability(dock->input, EV_KEY, tf103c_dock_toprow_codes[i][0]);
                input_set_capability(dock->input, EV_KEY, tf103c_dock_toprow_codes[i][1]);
        }
        input_set_capability(dock->input, EV_KEY, KEY_RIGHTALT);

        ret = input_register_device(dock->input);
        if (ret)
                return ret;

        /* 4. Create HID device for the keyboard */
        dock->hid = hid_allocate_device();
        if (IS_ERR(dock->hid))
                return dev_err_probe(dev, PTR_ERR(dock->hid), "allocating hid dev\n");

        dock->hid->driver_data = dock;
        dock->hid->ll_driver = &tf103c_dock_hid_ll_driver;
        dock->hid->dev.parent = &client->dev;
        dock->hid->bus = BUS_I2C;
        dock->hid->vendor = 0x0b05;  /* USB_VENDOR_ID_ASUSTEK */
        dock->hid->product = 0x0103; /* From TF-103-C */
        dock->hid->version = 0x0100; /* 1.0 */
        strscpy(dock->hid->name, "Asus TF103C Dock Keyboard");
        strscpy(dock->hid->phys, dev_name(dev));

        ret = hid_add_device(dock->hid);
        if (ret)
                return dev_err_probe(dev, ret, "adding hid dev\n");

        /* 5. Setup irqchip for touchpad IRQ pass-through */
        dock->tp_irqchip.name = KBUILD_MODNAME;

        dock->tp_irq_domain = irq_domain_create_linear(NULL, 1, &irq_domain_simple_ops, NULL);
        if (!dock->tp_irq_domain)
                return -ENOMEM;

        dock->tp_irq = irq_create_mapping(dock->tp_irq_domain, 0);
        if (!dock->tp_irq)
                return -ENOMEM;

        irq_set_chip_data(dock->tp_irq, dock);
        irq_set_chip_and_handler(dock->tp_irq, &dock->tp_irqchip, handle_simple_irq);
        irq_set_nested_thread(dock->tp_irq, true);
        irq_set_noprobe(dock->tp_irq);

        dev_info(dev, "Asus TF103C board-revision: %d\n", dock->board_rev);

        tf103c_dock_start_hpd(dock);

        device_init_wakeup(dev, true);
        i2c_set_clientdata(client, dock);
        return 0;
}

static void tf103c_dock_remove(struct i2c_client *client)
{
        struct tf103c_dock_data *dock = i2c_get_clientdata(client);

        tf103c_dock_stop_hpd(dock);
        tf103c_dock_disable(dock);
}

static int __maybe_unused tf103c_dock_suspend(struct device *dev)
{
        struct tf103c_dock_data *dock = dev_get_drvdata(dev);

        tf103c_dock_stop_hpd(dock);

        if (dock->enabled) {
                tf103c_dock_ec_cmd(dock, tf103c_dock_suspend_cmd);

                if (device_may_wakeup(dev))
                        enable_irq_wake(dock->irq);
        }

        return 0;
}

static int __maybe_unused tf103c_dock_resume(struct device *dev)
{
        struct tf103c_dock_data *dock = dev_get_drvdata(dev);

        if (dock->enabled) {
                if (device_may_wakeup(dev))
                        disable_irq_wake(dock->irq);

                /* Don't try to resume if the dock was unplugged during suspend */
                if (gpiod_get_value(dock->hpd_gpio))
                        tf103c_dock_ec_cmd(dock, tf103c_dock_enable_cmd);
        }

        tf103c_dock_start_hpd(dock);
        return 0;
}

static SIMPLE_DEV_PM_OPS(tf103c_dock_pm_ops, tf103c_dock_suspend, tf103c_dock_resume);

static const struct acpi_device_id tf103c_dock_acpi_match[] = {
        {"NPCE69A"},
        { }
};
MODULE_DEVICE_TABLE(acpi, tf103c_dock_acpi_match);

static struct i2c_driver tf103c_dock_driver = {
        .driver = {
                .name = "asus-tf103c-dock",
                .pm = &tf103c_dock_pm_ops,
                .acpi_match_table = tf103c_dock_acpi_match,
        },
        .probe = tf103c_dock_probe,
        .remove = tf103c_dock_remove,
};
module_i2c_driver(tf103c_dock_driver);

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
MODULE_DESCRIPTION("X86 Android tablets DSDT fixups driver");
MODULE_LICENSE("GPL");