// SPDX-License-Identifier: GPL-2.0
/*
 * MacBook (Pro) SPI keyboard and touchpad driver
 *
 * Copyright (c) 2015-2018 Federico Lorenzi
 * Copyright (c) 2017-2018 Ronald Tschalär
 */

/*
 * The keyboard and touchpad controller on the MacBookAir6, MacBookPro12,
 * MacBook8 and newer can be driven either by USB or SPI. However the USB
 * pins are only connected on the MacBookAir6 and 7 and the MacBookPro12.
 * All others need this driver. The interface is selected using ACPI methods:
 *
 * * UIEN ("USB Interface Enable"): If invoked with argument 1, disables SPI
 *   and enables USB. If invoked with argument 0, disables USB.
 * * UIST ("USB Interface Status"): Returns 1 if USB is enabled, 0 otherwise.
 * * SIEN ("SPI Interface Enable"): If invoked with argument 1, disables USB
 *   and enables SPI. If invoked with argument 0, disables SPI.
 * * SIST ("SPI Interface Status"): Returns 1 if SPI is enabled, 0 otherwise.
 * * ISOL: Resets the four GPIO pins used for SPI. Intended to be invoked with
 *   argument 1, then once more with argument 0.
 *
 * UIEN and UIST are only provided on models where the USB pins are connected.
 *
 * SPI-based Protocol
 * ------------------
 *
 * The device and driver exchange messages (struct message); each message is
 * encapsulated in one or more packets (struct spi_packet). There are two types
 * of exchanges: reads, and writes. A read is signaled by a GPE, upon which one
 * message can be read from the device. A write exchange consists of writing a
 * command message, immediately reading a short status packet, and then, upon
 * receiving a GPE, reading the response message. Write exchanges cannot be
 * interleaved, i.e. a new write exchange must not be started till the previous
 * write exchange is complete. Whether a received message is part of a read or
 * write exchange is indicated in the encapsulating packet's flags field.
 *
 * A single message may be too large to fit in a single packet (which has a
 * fixed, 256-byte size). In that case it will be split over multiple,
 * consecutive packets.
 */

#include <linux/acpi.h>
#include <linux/crc16.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/efi.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/ktime.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/spi/spi.h>
#include <linux/wait.h>
#include <linux/workqueue.h>

#include <asm/barrier.h>
#include <asm/unaligned.h>

#define CREATE_TRACE_POINTS
#include "applespi.h"
#include "applespi_trace.h"

#define APPLESPI_PACKET_SIZE    256
#define APPLESPI_STATUS_SIZE    4

#define PACKET_TYPE_READ        0x20
#define PACKET_TYPE_WRITE       0x40
#define PACKET_DEV_KEYB         0x01
#define PACKET_DEV_TPAD         0x02
#define PACKET_DEV_INFO         0xd0

#define MAX_ROLLOVER            6

#define MAX_FINGERS             11
#define MAX_FINGER_ORIENTATION  16384
#define MAX_PKTS_PER_MSG        2

#define KBD_BL_LEVEL_MIN        32U
#define KBD_BL_LEVEL_MAX        255U
#define KBD_BL_LEVEL_SCALE      1000000U
#define KBD_BL_LEVEL_ADJ        \
        ((KBD_BL_LEVEL_MAX - KBD_BL_LEVEL_MIN) * KBD_BL_LEVEL_SCALE / 255U)

#define EFI_BL_LEVEL_NAME       L"KeyboardBacklightLevel"
#define EFI_BL_LEVEL_GUID       EFI_GUID(0xa076d2af, 0x9678, 0x4386, 0x8b, 0x58, 0x1f, 0xc8, 0xef, 0x04, 0x16, 0x19)

#define APPLE_FLAG_FKEY         0x01

#define SPI_RW_CHG_DELAY_US     100     /* from experimentation, in µs */

#define SYNAPTICS_VENDOR_ID     0x06cb

static unsigned int fnmode = 1;
module_param(fnmode, uint, 0644);
MODULE_PARM_DESC(fnmode, "Mode of Fn key on Apple keyboards (0 = disabled, [1] = fkeyslast, 2 = fkeysfirst)");

static unsigned int fnremap;
module_param(fnremap, uint, 0644);
MODULE_PARM_DESC(fnremap, "Remap Fn key ([0] = no-remap; 1 = left-ctrl, 2 = left-shift, 3 = left-alt, 4 = left-meta, 6 = right-shift, 7 = right-alt, 8 = right-meta)");

static bool iso_layout;
module_param(iso_layout, bool, 0644);
MODULE_PARM_DESC(iso_layout, "Enable/Disable hardcoded ISO-layout of the keyboard. ([0] = disabled, 1 = enabled)");

static char touchpad_dimensions[40];
module_param_string(touchpad_dimensions, touchpad_dimensions,
                    sizeof(touchpad_dimensions), 0444);
MODULE_PARM_DESC(touchpad_dimensions, "The pixel dimensions of the touchpad, as XxY+W+H .");

/**
 * struct keyboard_protocol - keyboard message.
 * message.type = 0x0110, message.length = 0x000a
 *
 * @unknown1:           unknown
 * @modifiers:          bit-set of modifier/control keys pressed
 * @unknown2:           unknown
 * @keys_pressed:       the (non-modifier) keys currently pressed
 * @fn_pressed:         whether the fn key is currently pressed
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct keyboard_protocol {
        u8                      unknown1;
        u8                      modifiers;
        u8                      unknown2;
        u8                      keys_pressed[MAX_ROLLOVER];
        u8                      fn_pressed;
        __le16                  crc16;
};

/**
 * struct tp_finger - single trackpad finger structure, le16-aligned
 *
 * @origin:             zero when switching track finger
 * @abs_x:              absolute x coordinate
 * @abs_y:              absolute y coordinate
 * @rel_x:              relative x coordinate
 * @rel_y:              relative y coordinate
 * @tool_major:         tool area, major axis
 * @tool_minor:         tool area, minor axis
 * @orientation:        16384 when point, else 15 bit angle
 * @touch_major:        touch area, major axis
 * @touch_minor:        touch area, minor axis
 * @unused:             zeros
 * @pressure:           pressure on forcetouch touchpad
 * @multi:              one finger: varies, more fingers: constant
 * @crc16:              on last finger: crc over the whole message struct
 *                      (i.e. message header + this struct) minus the last
 *                      @crc16 field; unknown on all other fingers.
 */
struct tp_finger {
        __le16 origin;
        __le16 abs_x;
        __le16 abs_y;
        __le16 rel_x;
        __le16 rel_y;
        __le16 tool_major;
        __le16 tool_minor;
        __le16 orientation;
        __le16 touch_major;
        __le16 touch_minor;
        __le16 unused[2];
        __le16 pressure;
        __le16 multi;
        __le16 crc16;
};

/**
 * struct touchpad_protocol - touchpad message.
 * message.type = 0x0210
 *
 * @unknown1:           unknown
 * @clicked:            1 if a button-click was detected, 0 otherwise
 * @unknown2:           unknown
 * @number_of_fingers:  the number of fingers being reported in @fingers
 * @clicked2:           same as @clicked
 * @unknown3:           unknown
 * @fingers:            the data for each finger
 */
struct touchpad_protocol {
        u8                      unknown1[1];
        u8                      clicked;
        u8                      unknown2[28];
        u8                      number_of_fingers;
        u8                      clicked2;
        u8                      unknown3[16];
        struct tp_finger        fingers[];
};

/**
 * struct command_protocol_tp_info - get touchpad info.
 * message.type = 0x1020, message.length = 0x0000
 *
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct command_protocol_tp_info {
        __le16                  crc16;
};

/**
 * struct touchpad_info - touchpad info response.
 * message.type = 0x1020, message.length = 0x006e
 *
 * @unknown1:           unknown
 * @model_flags:        flags (vary by model number, but significance otherwise
 *                      unknown)
 * @model_no:           the touchpad model number
 * @unknown2:           unknown
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct touchpad_info_protocol {
        u8                      unknown1[105];
        u8                      model_flags;
        u8                      model_no;
        u8                      unknown2[3];
        __le16                  crc16;
};

/**
 * struct command_protocol_mt_init - initialize multitouch.
 * message.type = 0x0252, message.length = 0x0002
 *
 * @cmd:                value: 0x0102
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct command_protocol_mt_init {
        __le16                  cmd;
        __le16                  crc16;
};

/**
 * struct command_protocol_capsl - toggle caps-lock led
 * message.type = 0x0151, message.length = 0x0002
 *
 * @unknown:            value: 0x01 (length?)
 * @led:                0 off, 2 on
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct command_protocol_capsl {
        u8                      unknown;
        u8                      led;
        __le16                  crc16;
};

/**
 * struct command_protocol_bl - set keyboard backlight brightness
 * message.type = 0xB051, message.length = 0x0006
 *
 * @const1:             value: 0x01B0
 * @level:              the brightness level to set
 * @const2:             value: 0x0001 (backlight off), 0x01F4 (backlight on)
 * @crc16:              crc over the whole message struct (message header +
 *                      this struct) minus this @crc16 field
 */
struct command_protocol_bl {
        __le16                  const1;
        __le16                  level;
        __le16                  const2;
        __le16                  crc16;
};

/**
 * struct message - a complete spi message.
 *
 * Each message begins with fixed header, followed by a message-type specific
 * payload, and ends with a 16-bit crc. Because of the varying lengths of the
 * payload, the crc is defined at the end of each payload struct, rather than
 * in this struct.
 *
 * @type:       the message type
 * @zero:       always 0
 * @counter:    incremented on each message, rolls over after 255; there is a
 *              separate counter for each message type.
 * @rsp_buf_len:response buffer length (the exact nature of this field is quite
 *              speculative). On a request/write this is often the same as
 *              @length, though in some cases it has been seen to be much larger
 *              (e.g. 0x400); on a response/read this the same as on the
 *              request; for reads that are not responses it is 0.
 * @length:     length of the remainder of the data in the whole message
 *              structure (after re-assembly in case of being split over
 *              multiple spi-packets), minus the trailing crc. The total size
 *              of the message struct is therefore @length + 10.
 *
 * @keyboard:           Keyboard message
 * @touchpad:           Touchpad message
 * @tp_info:            Touchpad info (response)
 * @tp_info_command:    Touchpad info (CRC)
 * @init_mt_command:    Initialise Multitouch
 * @capsl_command:      Toggle caps-lock LED
 * @bl_command:         Keyboard brightness
 * @data:               Buffer data
 */
struct message {
        __le16          type;
        u8              zero;
        u8              counter;
        __le16          rsp_buf_len;
        __le16          length;
        union {
                struct keyboard_protocol        keyboard;
                struct touchpad_protocol        touchpad;
                struct touchpad_info_protocol   tp_info;
                struct command_protocol_tp_info tp_info_command;
                struct command_protocol_mt_init init_mt_command;
                struct command_protocol_capsl   capsl_command;
                struct command_protocol_bl      bl_command;
                u8                              data[0];
        };
};

/* type + zero + counter + rsp_buf_len + length */
#define MSG_HEADER_SIZE         8

/**
 * struct spi_packet - a complete spi packet; always 256 bytes. This carries
 * the (parts of the) message in the data. But note that this does not
 * necessarily contain a complete message, as in some cases (e.g. many
 * fingers pressed) the message is split over multiple packets (see the
 * @offset, @remaining, and @length fields). In general the data parts in
 * spi_packet's are concatenated until @remaining is 0, and the result is an
 * message.
 *
 * @flags:      0x40 = write (to device), 0x20 = read (from device); note that
 *              the response to a write still has 0x40.
 * @device:     1 = keyboard, 2 = touchpad
 * @offset:     specifies the offset of this packet's data in the complete
 *              message; i.e. > 0 indicates this is a continuation packet (in
 *              the second packet for a message split over multiple packets
 *              this would then be the same as the @length in the first packet)
 * @remaining:  number of message bytes remaining in subsequents packets (in
 *              the first packet of a message split over two packets this would
 *              then be the same as the @length in the second packet)
 * @length:     length of the valid data in the @data in this packet
 * @data:       all or part of a message
 * @crc16:      crc over this whole structure minus this @crc16 field. This
 *              covers just this packet, even on multi-packet messages (in
 *              contrast to the crc in the message).
 */
struct spi_packet {
        u8                      flags;
        u8                      device;
        __le16                  offset;
        __le16                  remaining;
        __le16                  length;
        u8                      data[246];
        __le16                  crc16;
};

struct spi_settings {
        u64     spi_cs_delay;           /* cs-to-clk delay in us */
        u64     reset_a2r_usec;         /* active-to-receive delay? */
        u64     reset_rec_usec;         /* ? (cur val: 10) */
};

/* this mimics struct drm_rect */
struct applespi_tp_info {
        int     x_min;
        int     y_min;
        int     x_max;
        int     y_max;
};

struct applespi_data {
        struct spi_device               *spi;
        struct spi_settings             spi_settings;
        struct input_dev                *keyboard_input_dev;
        struct input_dev                *touchpad_input_dev;

        u8                              *tx_buffer;
        u8                              *tx_status;
        u8                              *rx_buffer;

        u8                              *msg_buf;
        unsigned int                    saved_msg_len;

        struct applespi_tp_info         tp_info;

        u8                              last_keys_pressed[MAX_ROLLOVER];
        u8                              last_keys_fn_pressed[MAX_ROLLOVER];
        u8                              last_fn_pressed;
        struct input_mt_pos             pos[MAX_FINGERS];
        int                             slots[MAX_FINGERS];
        int                             gpe;
        acpi_handle                     sien;
        acpi_handle                     sist;

        struct spi_transfer             dl_t;
        struct spi_transfer             rd_t;
        struct spi_message              rd_m;

        struct spi_transfer             ww_t;
        struct spi_transfer             wd_t;
        struct spi_transfer             wr_t;
        struct spi_transfer             st_t;
        struct spi_message              wr_m;

        bool                            want_tp_info_cmd;
        bool                            want_mt_init_cmd;
        bool                            want_cl_led_on;
        bool                            have_cl_led_on;
        unsigned int                    want_bl_level;
        unsigned int                    have_bl_level;
        unsigned int                    cmd_msg_cntr;
        /* lock to protect the above parameters and flags below */
        spinlock_t                      cmd_msg_lock;
        ktime_t                         cmd_msg_queued;
        enum applespi_evt_type          cmd_evt_type;

        struct led_classdev             backlight_info;

        bool                            suspended;
        bool                            drain;
        wait_queue_head_t               drain_complete;
        bool                            read_active;
        bool                            write_active;

        struct work_struct              work;
        struct touchpad_info_protocol   rcvd_tp_info;

        struct dentry                   *debugfs_root;
        bool                            debug_tp_dim;
        char                            tp_dim_val[40];
        int                             tp_dim_min_x;
        int                             tp_dim_max_x;
        int                             tp_dim_min_y;
        int                             tp_dim_max_y;
};

static const unsigned char applespi_scancodes[] = {
        0, 0, 0, 0,
        KEY_A, KEY_B, KEY_C, KEY_D, KEY_E, KEY_F, KEY_G, KEY_H, KEY_I, KEY_J,
        KEY_K, KEY_L, KEY_M, KEY_N, KEY_O, KEY_P, KEY_Q, KEY_R, KEY_S, KEY_T,
        KEY_U, KEY_V, KEY_W, KEY_X, KEY_Y, KEY_Z,
        KEY_1, KEY_2, KEY_3, KEY_4, KEY_5, KEY_6, KEY_7, KEY_8, KEY_9, KEY_0,
        KEY_ENTER, KEY_ESC, KEY_BACKSPACE, KEY_TAB, KEY_SPACE, KEY_MINUS,
        KEY_EQUAL, KEY_LEFTBRACE, KEY_RIGHTBRACE, KEY_BACKSLASH, 0,
        KEY_SEMICOLON, KEY_APOSTROPHE, KEY_GRAVE, KEY_COMMA, KEY_DOT, KEY_SLASH,
        KEY_CAPSLOCK,
        KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5, KEY_F6, KEY_F7, KEY_F8, KEY_F9,
        KEY_F10, KEY_F11, KEY_F12, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        KEY_RIGHT, KEY_LEFT, KEY_DOWN, KEY_UP,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, KEY_102ND,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, KEY_RO, 0, KEY_YEN, 0, 0, 0, 0, 0,
        0, KEY_KATAKANAHIRAGANA, KEY_MUHENKAN
};

/*
 * This must have exactly as many entries as there are bits in
 * struct keyboard_protocol.modifiers .
 */
static const unsigned char applespi_controlcodes[] = {
        KEY_LEFTCTRL,
        KEY_LEFTSHIFT,
        KEY_LEFTALT,
        KEY_LEFTMETA,
        0,
        KEY_RIGHTSHIFT,
        KEY_RIGHTALT,
        KEY_RIGHTMETA
};

struct applespi_key_translation {
        u16 from;
        u16 to;
        u8 flags;
};

static const struct applespi_key_translation applespi_fn_codes[] = {
        { KEY_BACKSPACE, KEY_DELETE },
        { KEY_ENTER,    KEY_INSERT },
        { KEY_F1,       KEY_BRIGHTNESSDOWN,     APPLE_FLAG_FKEY },
        { KEY_F2,       KEY_BRIGHTNESSUP,       APPLE_FLAG_FKEY },
        { KEY_F3,       KEY_SCALE,              APPLE_FLAG_FKEY },
        { KEY_F4,       KEY_DASHBOARD,          APPLE_FLAG_FKEY },
        { KEY_F5,       KEY_KBDILLUMDOWN,       APPLE_FLAG_FKEY },
        { KEY_F6,       KEY_KBDILLUMUP,         APPLE_FLAG_FKEY },
        { KEY_F7,       KEY_PREVIOUSSONG,       APPLE_FLAG_FKEY },
        { KEY_F8,       KEY_PLAYPAUSE,          APPLE_FLAG_FKEY },
        { KEY_F9,       KEY_NEXTSONG,           APPLE_FLAG_FKEY },
        { KEY_F10,      KEY_MUTE,               APPLE_FLAG_FKEY },
        { KEY_F11,      KEY_VOLUMEDOWN,         APPLE_FLAG_FKEY },
        { KEY_F12,      KEY_VOLUMEUP,           APPLE_FLAG_FKEY },
        { KEY_RIGHT,    KEY_END },
        { KEY_LEFT,     KEY_HOME },
        { KEY_DOWN,     KEY_PAGEDOWN },
        { KEY_UP,       KEY_PAGEUP },
        { }
};

static const struct applespi_key_translation apple_iso_keyboard[] = {
        { KEY_GRAVE,    KEY_102ND },
        { KEY_102ND,    KEY_GRAVE },
        { }
};

struct applespi_tp_model_info {
        u16                     model;
        struct applespi_tp_info tp_info;
};

static const struct applespi_tp_model_info applespi_tp_models[] = {
        {
                .model = 0x04,  /* MB8 MB9 MB10 */
                .tp_info = { -5087, -182, 5579, 6089 },
        },
        {
                .model = 0x05,  /* MBP13,1 MBP13,2 MBP14,1 MBP14,2 */
                .tp_info = { -6243, -170, 6749, 7685 },
        },
        {
                .model = 0x06,  /* MBP13,3 MBP14,3 */
                .tp_info = { -7456, -163, 7976, 9283 },
        },
        {}
};

typedef void (*applespi_trace_fun)(enum applespi_evt_type,
                                   enum applespi_pkt_type, u8 *, size_t);

static applespi_trace_fun applespi_get_trace_fun(enum applespi_evt_type type)
{
        switch (type) {
        case ET_CMD_TP_INI:
                return trace_applespi_tp_ini_cmd;
        case ET_CMD_BL:
                return trace_applespi_backlight_cmd;
        case ET_CMD_CL:
                return trace_applespi_caps_lock_cmd;
        case ET_RD_KEYB:
                return trace_applespi_keyboard_data;
        case ET_RD_TPAD:
                return trace_applespi_touchpad_data;
        case ET_RD_UNKN:
                return trace_applespi_unknown_data;
        default:
                WARN_ONCE(1, "Unknown msg type %d", type);
                return trace_applespi_unknown_data;
        }
}

static void applespi_setup_read_txfrs(struct applespi_data *applespi)
{
        struct spi_message *msg = &applespi->rd_m;
        struct spi_transfer *dl_t = &applespi->dl_t;
        struct spi_transfer *rd_t = &applespi->rd_t;

        memset(dl_t, 0, sizeof(*dl_t));
        memset(rd_t, 0, sizeof(*rd_t));

        dl_t->delay.value = applespi->spi_settings.spi_cs_delay;
        dl_t->delay.unit = SPI_DELAY_UNIT_USECS;

        rd_t->rx_buf = applespi->rx_buffer;
        rd_t->len = APPLESPI_PACKET_SIZE;

        spi_message_init(msg);
        spi_message_add_tail(dl_t, msg);
        spi_message_add_tail(rd_t, msg);
}

static void applespi_setup_write_txfrs(struct applespi_data *applespi)
{
        struct spi_message *msg = &applespi->wr_m;
        struct spi_transfer *wt_t = &applespi->ww_t;
        struct spi_transfer *dl_t = &applespi->wd_t;
        struct spi_transfer *wr_t = &applespi->wr_t;
        struct spi_transfer *st_t = &applespi->st_t;

        memset(wt_t, 0, sizeof(*wt_t));
        memset(dl_t, 0, sizeof(*dl_t));
        memset(wr_t, 0, sizeof(*wr_t));
        memset(st_t, 0, sizeof(*st_t));

        /*
         * All we need here is a delay at the beginning of the message before
         * asserting cs. But the current spi API doesn't support this, so we
         * end up with an extra unnecessary (but harmless) cs assertion and
         * deassertion.
         */
        wt_t->delay.value = SPI_RW_CHG_DELAY_US;
        wt_t->delay.unit = SPI_DELAY_UNIT_USECS;
        wt_t->cs_change = 1;

        dl_t->delay.value = applespi->spi_settings.spi_cs_delay;
        dl_t->delay.unit = SPI_DELAY_UNIT_USECS;

        wr_t->tx_buf = applespi->tx_buffer;
        wr_t->len = APPLESPI_PACKET_SIZE;
        wr_t->delay.value = SPI_RW_CHG_DELAY_US;
        wr_t->delay.unit = SPI_DELAY_UNIT_USECS;

        st_t->rx_buf = applespi->tx_status;
        st_t->len = APPLESPI_STATUS_SIZE;

        spi_message_init(msg);
        spi_message_add_tail(wt_t, msg);
        spi_message_add_tail(dl_t, msg);
        spi_message_add_tail(wr_t, msg);
        spi_message_add_tail(st_t, msg);
}

static int applespi_async(struct applespi_data *applespi,
                          struct spi_message *message, void (*complete)(void *))
{
        message->complete = complete;
        message->context = applespi;

        return spi_async(applespi->spi, message);
}

static inline bool applespi_check_write_status(struct applespi_data *applespi,
                                               int sts)
{
        static u8 status_ok[] = { 0xac, 0x27, 0x68, 0xd5 };

        if (sts < 0) {
                dev_warn(&applespi->spi->dev, "Error writing to device: %d\n",
                         sts);
                return false;
        }

        if (memcmp(applespi->tx_status, status_ok, APPLESPI_STATUS_SIZE)) {
                dev_warn(&applespi->spi->dev, "Error writing to device: %*ph\n",
                         APPLESPI_STATUS_SIZE, applespi->tx_status);
                return false;
        }

        return true;
}

static int applespi_get_spi_settings(struct applespi_data *applespi)
{
        struct acpi_device *adev = ACPI_COMPANION(&applespi->spi->dev);
        const union acpi_object *o;
        struct spi_settings *settings = &applespi->spi_settings;

        if (!acpi_dev_get_property(adev, "spiCSDelay", ACPI_TYPE_BUFFER, &o))
                settings->spi_cs_delay = *(u64 *)o->buffer.pointer;
        else
                dev_warn(&applespi->spi->dev,
                         "Property spiCSDelay not found\n");

        if (!acpi_dev_get_property(adev, "resetA2RUsec", ACPI_TYPE_BUFFER, &o))
                settings->reset_a2r_usec = *(u64 *)o->buffer.pointer;
        else
                dev_warn(&applespi->spi->dev,
                         "Property resetA2RUsec not found\n");

        if (!acpi_dev_get_property(adev, "resetRecUsec", ACPI_TYPE_BUFFER, &o))
                settings->reset_rec_usec = *(u64 *)o->buffer.pointer;
        else
                dev_warn(&applespi->spi->dev,
                         "Property resetRecUsec not found\n");

        dev_dbg(&applespi->spi->dev,
                "SPI settings: spi_cs_delay=%llu reset_a2r_usec=%llu reset_rec_usec=%llu\n",
                settings->spi_cs_delay, settings->reset_a2r_usec,
                settings->reset_rec_usec);

        return 0;
}

static int applespi_setup_spi(struct applespi_data *applespi)
{
        int sts;

        sts = applespi_get_spi_settings(applespi);
        if (sts)
                return sts;

        spin_lock_init(&applespi->cmd_msg_lock);
        init_waitqueue_head(&applespi->drain_complete);

        return 0;
}

static int applespi_enable_spi(struct applespi_data *applespi)
{
        acpi_status acpi_sts;
        unsigned long long spi_status;

        /* check if SPI is already enabled, so we can skip the delay below */
        acpi_sts = acpi_evaluate_integer(applespi->sist, NULL, NULL,
                                         &spi_status);
        if (ACPI_SUCCESS(acpi_sts) && spi_status)
                return 0;

        /* SIEN(1) will enable SPI communication */
        acpi_sts = acpi_execute_simple_method(applespi->sien, NULL, 1);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev, "SIEN failed: %s\n",
                        acpi_format_exception(acpi_sts));
                return -ENODEV;
        }

        /*
         * Allow the SPI interface to come up before returning. Without this
         * delay, the SPI commands to enable multitouch mode may not reach
         * the trackpad controller, causing pointer movement to break upon
         * resume from sleep.
         */
        msleep(50);

        return 0;
}

static int applespi_send_cmd_msg(struct applespi_data *applespi);

static void applespi_msg_complete(struct applespi_data *applespi,
                                  bool is_write_msg, bool is_read_compl)
{
        unsigned long flags;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        if (is_read_compl)
                applespi->read_active = false;
        if (is_write_msg)
                applespi->write_active = false;

        if (applespi->drain && !applespi->write_active)
                wake_up_all(&applespi->drain_complete);

        if (is_write_msg) {
                applespi->cmd_msg_queued = 0;
                applespi_send_cmd_msg(applespi);
        }

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
}

static void applespi_async_write_complete(void *context)
{
        struct applespi_data *applespi = context;
        enum applespi_evt_type evt_type = applespi->cmd_evt_type;

        applespi_get_trace_fun(evt_type)(evt_type, PT_WRITE,
                                         applespi->tx_buffer,
                                         APPLESPI_PACKET_SIZE);
        applespi_get_trace_fun(evt_type)(evt_type, PT_STATUS,
                                         applespi->tx_status,
                                         APPLESPI_STATUS_SIZE);

        udelay(SPI_RW_CHG_DELAY_US);

        if (!applespi_check_write_status(applespi, applespi->wr_m.status)) {
                /*
                 * If we got an error, we presumably won't get the expected
                 * response message either.
                 */
                applespi_msg_complete(applespi, true, false);
        }
}

static int applespi_send_cmd_msg(struct applespi_data *applespi)
{
        u16 crc;
        int sts;
        struct spi_packet *packet = (struct spi_packet *)applespi->tx_buffer;
        struct message *message = (struct message *)packet->data;
        u16 msg_len;
        u8 device;

        /* check if draining */
        if (applespi->drain)
                return 0;

        /* check whether send is in progress */
        if (applespi->cmd_msg_queued) {
                if (ktime_ms_delta(ktime_get(), applespi->cmd_msg_queued) < 1000)
                        return 0;

                dev_warn(&applespi->spi->dev, "Command %d timed out\n",
                         applespi->cmd_evt_type);

                applespi->cmd_msg_queued = 0;
                applespi->write_active = false;
        }

        /* set up packet */
        memset(packet, 0, APPLESPI_PACKET_SIZE);

        /* are we processing init commands? */
        if (applespi->want_tp_info_cmd) {
                applespi->want_tp_info_cmd = false;
                applespi->want_mt_init_cmd = true;
                applespi->cmd_evt_type = ET_CMD_TP_INI;

                /* build init command */
                device = PACKET_DEV_INFO;

                message->type = cpu_to_le16(0x1020);
                msg_len = sizeof(message->tp_info_command);

                message->zero = 0x02;
                message->rsp_buf_len = cpu_to_le16(0x0200);

        } else if (applespi->want_mt_init_cmd) {
                applespi->want_mt_init_cmd = false;
                applespi->cmd_evt_type = ET_CMD_TP_INI;

                /* build init command */
                device = PACKET_DEV_TPAD;

                message->type = cpu_to_le16(0x0252);
                msg_len = sizeof(message->init_mt_command);

                message->init_mt_command.cmd = cpu_to_le16(0x0102);

        /* do we need caps-lock command? */
        } else if (applespi->want_cl_led_on != applespi->have_cl_led_on) {
                applespi->have_cl_led_on = applespi->want_cl_led_on;
                applespi->cmd_evt_type = ET_CMD_CL;

                /* build led command */
                device = PACKET_DEV_KEYB;

                message->type = cpu_to_le16(0x0151);
                msg_len = sizeof(message->capsl_command);

                message->capsl_command.unknown = 0x01;
                message->capsl_command.led = applespi->have_cl_led_on ? 2 : 0;

        /* do we need backlight command? */
        } else if (applespi->want_bl_level != applespi->have_bl_level) {
                applespi->have_bl_level = applespi->want_bl_level;
                applespi->cmd_evt_type = ET_CMD_BL;

                /* build command buffer */
                device = PACKET_DEV_KEYB;

                message->type = cpu_to_le16(0xB051);
                msg_len = sizeof(message->bl_command);

                message->bl_command.const1 = cpu_to_le16(0x01B0);
                message->bl_command.level =
                                cpu_to_le16(applespi->have_bl_level);

                if (applespi->have_bl_level > 0)
                        message->bl_command.const2 = cpu_to_le16(0x01F4);
                else
                        message->bl_command.const2 = cpu_to_le16(0x0001);

        /* everything's up-to-date */
        } else {
                return 0;
        }

        /* finalize packet */
        packet->flags = PACKET_TYPE_WRITE;
        packet->device = device;
        packet->length = cpu_to_le16(MSG_HEADER_SIZE + msg_len);

        message->counter = applespi->cmd_msg_cntr++ % (U8_MAX + 1);

        message->length = cpu_to_le16(msg_len - 2);
        if (!message->rsp_buf_len)
                message->rsp_buf_len = message->length;

        crc = crc16(0, (u8 *)message, le16_to_cpu(packet->length) - 2);
        put_unaligned_le16(crc, &message->data[msg_len - 2]);

        crc = crc16(0, (u8 *)packet, sizeof(*packet) - 2);
        packet->crc16 = cpu_to_le16(crc);

        /* send command */
        sts = applespi_async(applespi, &applespi->wr_m,
                             applespi_async_write_complete);
        if (sts) {
                dev_warn(&applespi->spi->dev,
                         "Error queueing async write to device: %d\n", sts);
                return sts;
        }

        applespi->cmd_msg_queued = ktime_get_coarse();
        applespi->write_active = true;

        return 0;
}

static void applespi_init(struct applespi_data *applespi, bool is_resume)
{
        unsigned long flags;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        if (is_resume)
                applespi->want_mt_init_cmd = true;
        else
                applespi->want_tp_info_cmd = true;
        applespi_send_cmd_msg(applespi);

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
}

static int applespi_set_capsl_led(struct applespi_data *applespi,
                                  bool capslock_on)
{
        unsigned long flags;
        int sts;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        applespi->want_cl_led_on = capslock_on;
        sts = applespi_send_cmd_msg(applespi);

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);

        return sts;
}

static void applespi_set_bl_level(struct led_classdev *led_cdev,
                                  enum led_brightness value)
{
        struct applespi_data *applespi =
                container_of(led_cdev, struct applespi_data, backlight_info);
        unsigned long flags;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        if (value == 0) {
                applespi->want_bl_level = value;
        } else {
                /*
                 * The backlight does not turn on till level 32, so we scale
                 * the range here so that from a user's perspective it turns
                 * on at 1.
                 */
                applespi->want_bl_level =
                        ((value * KBD_BL_LEVEL_ADJ) / KBD_BL_LEVEL_SCALE +
                         KBD_BL_LEVEL_MIN);
        }

        applespi_send_cmd_msg(applespi);

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
}

static int applespi_event(struct input_dev *dev, unsigned int type,
                          unsigned int code, int value)
{
        struct applespi_data *applespi = input_get_drvdata(dev);

        switch (type) {
        case EV_LED:
                applespi_set_capsl_led(applespi, !!test_bit(LED_CAPSL, dev->led));
                return 0;
        }

        return -EINVAL;
}

/* lifted from the BCM5974 driver and renamed from raw2int */
/* convert 16-bit little endian to signed integer */
static inline int le16_to_int(__le16 x)
{
        return (signed short)le16_to_cpu(x);
}

static void applespi_debug_update_dimensions(struct applespi_data *applespi,
                                             const struct tp_finger *f)
{
        applespi->tp_dim_min_x = min(applespi->tp_dim_min_x,
                                     le16_to_int(f->abs_x));
        applespi->tp_dim_max_x = max(applespi->tp_dim_max_x,
                                     le16_to_int(f->abs_x));
        applespi->tp_dim_min_y = min(applespi->tp_dim_min_y,
                                     le16_to_int(f->abs_y));
        applespi->tp_dim_max_y = max(applespi->tp_dim_max_y,
                                     le16_to_int(f->abs_y));
}

static int applespi_tp_dim_open(struct inode *inode, struct file *file)
{
        struct applespi_data *applespi = inode->i_private;

        file->private_data = applespi;

        snprintf(applespi->tp_dim_val, sizeof(applespi->tp_dim_val),
                 "0x%.4x %dx%d+%u+%u\n",
                 applespi->touchpad_input_dev->id.product,
                 applespi->tp_dim_min_x, applespi->tp_dim_min_y,
                 applespi->tp_dim_max_x - applespi->tp_dim_min_x,
                 applespi->tp_dim_max_y - applespi->tp_dim_min_y);

        return nonseekable_open(inode, file);
}

static ssize_t applespi_tp_dim_read(struct file *file, char __user *buf,
                                    size_t len, loff_t *off)
{
        struct applespi_data *applespi = file->private_data;

        return simple_read_from_buffer(buf, len, off, applespi->tp_dim_val,
                                       strlen(applespi->tp_dim_val));
}

static const struct file_operations applespi_tp_dim_fops = {
        .owner = THIS_MODULE,
        .open = applespi_tp_dim_open,
        .read = applespi_tp_dim_read,
        .llseek = no_llseek,
};

static void report_finger_data(struct input_dev *input, int slot,
                               const struct input_mt_pos *pos,
                               const struct tp_finger *f)
{
        input_mt_slot(input, slot);
        input_mt_report_slot_state(input, MT_TOOL_FINGER, true);

        input_report_abs(input, ABS_MT_TOUCH_MAJOR,
                         le16_to_int(f->touch_major) << 1);
        input_report_abs(input, ABS_MT_TOUCH_MINOR,
                         le16_to_int(f->touch_minor) << 1);
        input_report_abs(input, ABS_MT_WIDTH_MAJOR,
                         le16_to_int(f->tool_major) << 1);
        input_report_abs(input, ABS_MT_WIDTH_MINOR,
                         le16_to_int(f->tool_minor) << 1);
        input_report_abs(input, ABS_MT_ORIENTATION,
                         MAX_FINGER_ORIENTATION - le16_to_int(f->orientation));
        input_report_abs(input, ABS_MT_POSITION_X, pos->x);
        input_report_abs(input, ABS_MT_POSITION_Y, pos->y);
}

static void report_tp_state(struct applespi_data *applespi,
                            struct touchpad_protocol *t)
{
        const struct tp_finger *f;
        struct input_dev *input;
        const struct applespi_tp_info *tp_info = &applespi->tp_info;
        int i, n;

        /* touchpad_input_dev is set async in worker */
        input = smp_load_acquire(&applespi->touchpad_input_dev);
        if (!input)
                return; /* touchpad isn't initialized yet */

        n = 0;

        for (i = 0; i < t->number_of_fingers; i++) {
                f = &t->fingers[i];
                if (le16_to_int(f->touch_major) == 0)
                        continue;
                applespi->pos[n].x = le16_to_int(f->abs_x);
                applespi->pos[n].y = tp_info->y_min + tp_info->y_max -
                                     le16_to_int(f->abs_y);
                n++;

                if (applespi->debug_tp_dim)
                        applespi_debug_update_dimensions(applespi, f);
        }

        input_mt_assign_slots(input, applespi->slots, applespi->pos, n, 0);

        for (i = 0; i < n; i++)
                report_finger_data(input, applespi->slots[i],
                                   &applespi->pos[i], &t->fingers[i]);

        input_mt_sync_frame(input);
        input_report_key(input, BTN_LEFT, t->clicked);

        input_sync(input);
}

static const struct applespi_key_translation *
applespi_find_translation(const struct applespi_key_translation *table, u16 key)
{
        const struct applespi_key_translation *trans;

        for (trans = table; trans->from; trans++)
                if (trans->from == key)
                        return trans;

        return NULL;
}

static unsigned int applespi_translate_fn_key(unsigned int key, int fn_pressed)
{
        const struct applespi_key_translation *trans;
        int do_translate;

        trans = applespi_find_translation(applespi_fn_codes, key);
        if (trans) {
                if (trans->flags & APPLE_FLAG_FKEY)
                        do_translate = (fnmode == 2 && fn_pressed) ||
                                       (fnmode == 1 && !fn_pressed);
                else
                        do_translate = fn_pressed;

                if (do_translate)
                        key = trans->to;
        }

        return key;
}

static unsigned int applespi_translate_iso_layout(unsigned int key)
{
        const struct applespi_key_translation *trans;

        trans = applespi_find_translation(apple_iso_keyboard, key);
        if (trans)
                key = trans->to;

        return key;
}

static unsigned int applespi_code_to_key(u8 code, int fn_pressed)
{
        unsigned int key = applespi_scancodes[code];

        if (fnmode)
                key = applespi_translate_fn_key(key, fn_pressed);
        if (iso_layout)
                key = applespi_translate_iso_layout(key);
        return key;
}

static void
applespi_remap_fn_key(struct keyboard_protocol *keyboard_protocol)
{
        unsigned char tmp;
        u8 bit = BIT((fnremap - 1) & 0x07);

        if (!fnremap || fnremap > ARRAY_SIZE(applespi_controlcodes) ||
            !applespi_controlcodes[fnremap - 1])
                return;

        tmp = keyboard_protocol->fn_pressed;
        keyboard_protocol->fn_pressed = !!(keyboard_protocol->modifiers & bit);
        if (tmp)
                keyboard_protocol->modifiers |= bit;
        else
                keyboard_protocol->modifiers &= ~bit;
}

static void
applespi_handle_keyboard_event(struct applespi_data *applespi,
                               struct keyboard_protocol *keyboard_protocol)
{
        unsigned int key;
        int i;

        compiletime_assert(ARRAY_SIZE(applespi_controlcodes) ==
                           sizeof_field(struct keyboard_protocol, modifiers) * 8,
                           "applespi_controlcodes has wrong number of entries");

        /* check for rollover overflow, which is signalled by all keys == 1 */
        if (!memchr_inv(keyboard_protocol->keys_pressed, 1, MAX_ROLLOVER))
                return;

        /* remap fn key if desired */
        applespi_remap_fn_key(keyboard_protocol);

        /* check released keys */
        for (i = 0; i < MAX_ROLLOVER; i++) {
                if (memchr(keyboard_protocol->keys_pressed,
                           applespi->last_keys_pressed[i], MAX_ROLLOVER))
                        continue;       /* key is still pressed */

                key = applespi_code_to_key(applespi->last_keys_pressed[i],
                                           applespi->last_keys_fn_pressed[i]);
                input_report_key(applespi->keyboard_input_dev, key, 0);
                applespi->last_keys_fn_pressed[i] = 0;
        }

        /* check pressed keys */
        for (i = 0; i < MAX_ROLLOVER; i++) {
                if (keyboard_protocol->keys_pressed[i] <
                                ARRAY_SIZE(applespi_scancodes) &&
                    keyboard_protocol->keys_pressed[i] > 0) {
                        key = applespi_code_to_key(
                                        keyboard_protocol->keys_pressed[i],
                                        keyboard_protocol->fn_pressed);
                        input_report_key(applespi->keyboard_input_dev, key, 1);
                        applespi->last_keys_fn_pressed[i] =
                                        keyboard_protocol->fn_pressed;
                }
        }

        /* check control keys */
        for (i = 0; i < ARRAY_SIZE(applespi_controlcodes); i++) {
                if (keyboard_protocol->modifiers & BIT(i))
                        input_report_key(applespi->keyboard_input_dev,
                                         applespi_controlcodes[i], 1);
                else
                        input_report_key(applespi->keyboard_input_dev,
                                         applespi_controlcodes[i], 0);
        }

        /* check function key */
        if (keyboard_protocol->fn_pressed && !applespi->last_fn_pressed)
                input_report_key(applespi->keyboard_input_dev, KEY_FN, 1);
        else if (!keyboard_protocol->fn_pressed && applespi->last_fn_pressed)
                input_report_key(applespi->keyboard_input_dev, KEY_FN, 0);
        applespi->last_fn_pressed = keyboard_protocol->fn_pressed;

        /* done */
        input_sync(applespi->keyboard_input_dev);
        memcpy(&applespi->last_keys_pressed, keyboard_protocol->keys_pressed,
               sizeof(applespi->last_keys_pressed));
}

static const struct applespi_tp_info *applespi_find_touchpad_info(u8 model)
{
        const struct applespi_tp_model_info *info;

        for (info = applespi_tp_models; info->model; info++) {
                if (info->model == model)
                        return &info->tp_info;
        }

        return NULL;
}

static int
applespi_register_touchpad_device(struct applespi_data *applespi,
                                  struct touchpad_info_protocol *rcvd_tp_info)
{
        const struct applespi_tp_info *tp_info;
        struct input_dev *touchpad_input_dev;
        int sts;

        /* set up touchpad dimensions */
        tp_info = applespi_find_touchpad_info(rcvd_tp_info->model_no);
        if (!tp_info) {
                dev_warn(&applespi->spi->dev,
                         "Unknown touchpad model %x - falling back to MB8 touchpad\n",
                         rcvd_tp_info->model_no);
                tp_info = &applespi_tp_models[0].tp_info;
        }

        applespi->tp_info = *tp_info;

        if (touchpad_dimensions[0]) {
                int x, y, w, h;

                sts = sscanf(touchpad_dimensions, "%dx%d+%u+%u", &x, &y, &w, &h);
                if (sts == 4) {
                        dev_info(&applespi->spi->dev,
                                 "Overriding touchpad dimensions from module param\n");
                        applespi->tp_info.x_min = x;
                        applespi->tp_info.y_min = y;
                        applespi->tp_info.x_max = x + w;
                        applespi->tp_info.y_max = y + h;
                } else {
                        dev_warn(&applespi->spi->dev,
                                 "Invalid touchpad dimensions '%s': must be in the form XxY+W+H\n",
                                 touchpad_dimensions);
                        touchpad_dimensions[0] = '\0';
                }
        }
        if (!touchpad_dimensions[0]) {
                snprintf(touchpad_dimensions, sizeof(touchpad_dimensions),
                         "%dx%d+%u+%u",
                         applespi->tp_info.x_min,
                         applespi->tp_info.y_min,
                         applespi->tp_info.x_max - applespi->tp_info.x_min,
                         applespi->tp_info.y_max - applespi->tp_info.y_min);
        }

        /* create touchpad input device */
        touchpad_input_dev = devm_input_allocate_device(&applespi->spi->dev);
        if (!touchpad_input_dev) {
                dev_err(&applespi->spi->dev,
                        "Failed to allocate touchpad input device\n");
                return -ENOMEM;
        }

        touchpad_input_dev->name = "Apple SPI Touchpad";
        touchpad_input_dev->phys = "applespi/input1";
        touchpad_input_dev->dev.parent = &applespi->spi->dev;
        touchpad_input_dev->id.bustype = BUS_SPI;
        touchpad_input_dev->id.vendor = SYNAPTICS_VENDOR_ID;
        touchpad_input_dev->id.product =
                        rcvd_tp_info->model_no << 8 | rcvd_tp_info->model_flags;

        /* basic properties */
        input_set_capability(touchpad_input_dev, EV_REL, REL_X);
        input_set_capability(touchpad_input_dev, EV_REL, REL_Y);

        __set_bit(INPUT_PROP_POINTER, touchpad_input_dev->propbit);
        __set_bit(INPUT_PROP_BUTTONPAD, touchpad_input_dev->propbit);

        /* finger touch area */
        input_set_abs_params(touchpad_input_dev, ABS_MT_TOUCH_MAJOR,
                             0, 5000, 0, 0);
        input_set_abs_params(touchpad_input_dev, ABS_MT_TOUCH_MINOR,
                             0, 5000, 0, 0);

        /* finger approach area */
        input_set_abs_params(touchpad_input_dev, ABS_MT_WIDTH_MAJOR,
                             0, 5000, 0, 0);
        input_set_abs_params(touchpad_input_dev, ABS_MT_WIDTH_MINOR,
                             0, 5000, 0, 0);

        /* finger orientation */
        input_set_abs_params(touchpad_input_dev, ABS_MT_ORIENTATION,
                             -MAX_FINGER_ORIENTATION, MAX_FINGER_ORIENTATION,
                             0, 0);

        /* finger position */
        input_set_abs_params(touchpad_input_dev, ABS_MT_POSITION_X,
                             applespi->tp_info.x_min, applespi->tp_info.x_max,
                             0, 0);
        input_set_abs_params(touchpad_input_dev, ABS_MT_POSITION_Y,
                             applespi->tp_info.y_min, applespi->tp_info.y_max,
                             0, 0);

        /* touchpad button */
        input_set_capability(touchpad_input_dev, EV_KEY, BTN_LEFT);

        /* multitouch */
        sts = input_mt_init_slots(touchpad_input_dev, MAX_FINGERS,
                                  INPUT_MT_POINTER | INPUT_MT_DROP_UNUSED |
                                        INPUT_MT_TRACK);
        if (sts) {
                dev_err(&applespi->spi->dev,
                        "failed to initialize slots: %d", sts);
                return sts;
        }

        /* register input device */
        sts = input_register_device(touchpad_input_dev);
        if (sts) {
                dev_err(&applespi->spi->dev,
                        "Unable to register touchpad input device (%d)\n", sts);
                return sts;
        }

        /* touchpad_input_dev is read async in spi callback */
        smp_store_release(&applespi->touchpad_input_dev, touchpad_input_dev);

        return 0;
}

static void applespi_worker(struct work_struct *work)
{
        struct applespi_data *applespi =
                container_of(work, struct applespi_data, work);

        applespi_register_touchpad_device(applespi, &applespi->rcvd_tp_info);
}

static void applespi_handle_cmd_response(struct applespi_data *applespi,
                                         struct spi_packet *packet,
                                         struct message *message)
{
        if (packet->device == PACKET_DEV_INFO &&
            le16_to_cpu(message->type) == 0x1020) {
                /*
                 * We're not allowed to sleep here, but registering an input
                 * device can sleep.
                 */
                applespi->rcvd_tp_info = message->tp_info;
                schedule_work(&applespi->work);
                return;
        }

        if (le16_to_cpu(message->length) != 0x0000) {
                dev_warn_ratelimited(&applespi->spi->dev,
                                     "Received unexpected write response: length=%x\n",
                                     le16_to_cpu(message->length));
                return;
        }

        if (packet->device == PACKET_DEV_TPAD &&
            le16_to_cpu(message->type) == 0x0252 &&
            le16_to_cpu(message->rsp_buf_len) == 0x0002)
                dev_info(&applespi->spi->dev, "modeswitch done.\n");
}

static bool applespi_verify_crc(struct applespi_data *applespi, u8 *buffer,
                                size_t buflen)
{
        u16 crc;

        crc = crc16(0, buffer, buflen);
        if (crc) {
                dev_warn_ratelimited(&applespi->spi->dev,
                                     "Received corrupted packet (crc mismatch)\n");
                trace_applespi_bad_crc(ET_RD_CRC, READ, buffer, buflen);

                return false;
        }

        return true;
}

static void applespi_debug_print_read_packet(struct applespi_data *applespi,
                                             struct spi_packet *packet)
{
        unsigned int evt_type;

        if (packet->flags == PACKET_TYPE_READ &&
            packet->device == PACKET_DEV_KEYB)
                evt_type = ET_RD_KEYB;
        else if (packet->flags == PACKET_TYPE_READ &&
                 packet->device == PACKET_DEV_TPAD)
                evt_type = ET_RD_TPAD;
        else if (packet->flags == PACKET_TYPE_WRITE)
                evt_type = applespi->cmd_evt_type;
        else
                evt_type = ET_RD_UNKN;

        applespi_get_trace_fun(evt_type)(evt_type, PT_READ, applespi->rx_buffer,
                                         APPLESPI_PACKET_SIZE);
}

static void applespi_got_data(struct applespi_data *applespi)
{
        struct spi_packet *packet;
        struct message *message;
        unsigned int msg_len;
        unsigned int off;
        unsigned int rem;
        unsigned int len;

        /* process packet header */
        if (!applespi_verify_crc(applespi, applespi->rx_buffer,
                                 APPLESPI_PACKET_SIZE)) {
                unsigned long flags;

                spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

                if (applespi->drain) {
                        applespi->read_active = false;
                        applespi->write_active = false;

                        wake_up_all(&applespi->drain_complete);
                }

                spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);

                return;
        }

        packet = (struct spi_packet *)applespi->rx_buffer;

        applespi_debug_print_read_packet(applespi, packet);

        off = le16_to_cpu(packet->offset);
        rem = le16_to_cpu(packet->remaining);
        len = le16_to_cpu(packet->length);

        if (len > sizeof(packet->data)) {
                dev_warn_ratelimited(&applespi->spi->dev,
                                     "Received corrupted packet (invalid packet length %u)\n",
                                     len);
                goto msg_complete;
        }

        /* handle multi-packet messages */
        if (rem > 0 || off > 0) {
                if (off != applespi->saved_msg_len) {
                        dev_warn_ratelimited(&applespi->spi->dev,
                                             "Received unexpected offset (got %u, expected %u)\n",
                                             off, applespi->saved_msg_len);
                        goto msg_complete;
                }

                if (off + rem > MAX_PKTS_PER_MSG * APPLESPI_PACKET_SIZE) {
                        dev_warn_ratelimited(&applespi->spi->dev,
                                             "Received message too large (size %u)\n",
                                             off + rem);
                        goto msg_complete;
                }

                if (off + len > MAX_PKTS_PER_MSG * APPLESPI_PACKET_SIZE) {
                        dev_warn_ratelimited(&applespi->spi->dev,
                                             "Received message too large (size %u)\n",
                                             off + len);
                        goto msg_complete;
                }

                memcpy(applespi->msg_buf + off, &packet->data, len);
                applespi->saved_msg_len += len;

                if (rem > 0)
                        return;

                message = (struct message *)applespi->msg_buf;
                msg_len = applespi->saved_msg_len;
        } else {
                message = (struct message *)&packet->data;
                msg_len = len;
        }

        /* got complete message - verify */
        if (!applespi_verify_crc(applespi, (u8 *)message, msg_len))
                goto msg_complete;

        if (le16_to_cpu(message->length) != msg_len - MSG_HEADER_SIZE - 2) {
                dev_warn_ratelimited(&applespi->spi->dev,
                                     "Received corrupted packet (invalid message length %u - expected %u)\n",
                                     le16_to_cpu(message->length),
                                     msg_len - MSG_HEADER_SIZE - 2);
                goto msg_complete;
        }

        /* handle message */
        if (packet->flags == PACKET_TYPE_READ &&
            packet->device == PACKET_DEV_KEYB) {
                applespi_handle_keyboard_event(applespi, &message->keyboard);

        } else if (packet->flags == PACKET_TYPE_READ &&
                   packet->device == PACKET_DEV_TPAD) {
                struct touchpad_protocol *tp;
                size_t tp_len;

                tp = &message->touchpad;
                tp_len = struct_size(tp, fingers, tp->number_of_fingers);

                if (le16_to_cpu(message->length) + 2 != tp_len) {
                        dev_warn_ratelimited(&applespi->spi->dev,
                                             "Received corrupted packet (invalid message length %u - num-fingers %u, tp-len %zu)\n",
                                             le16_to_cpu(message->length),
                                             tp->number_of_fingers, tp_len);
                        goto msg_complete;
                }

                if (tp->number_of_fingers > MAX_FINGERS) {
                        dev_warn_ratelimited(&applespi->spi->dev,
                                             "Number of reported fingers (%u) exceeds max (%u))\n",
                                             tp->number_of_fingers,
                                             MAX_FINGERS);
                        tp->number_of_fingers = MAX_FINGERS;
                }

                report_tp_state(applespi, tp);

        } else if (packet->flags == PACKET_TYPE_WRITE) {
                applespi_handle_cmd_response(applespi, packet, message);
        }

msg_complete:
        applespi->saved_msg_len = 0;

        applespi_msg_complete(applespi, packet->flags == PACKET_TYPE_WRITE,
                              true);
}

static void applespi_async_read_complete(void *context)
{
        struct applespi_data *applespi = context;

        if (applespi->rd_m.status < 0) {
                dev_warn(&applespi->spi->dev, "Error reading from device: %d\n",
                         applespi->rd_m.status);
                /*
                 * We don't actually know if this was a pure read, or a response
                 * to a write. But this is a rare error condition that should
                 * never occur, so clearing both flags to avoid deadlock.
                 */
                applespi_msg_complete(applespi, true, true);
        } else {
                applespi_got_data(applespi);
        }

        acpi_finish_gpe(NULL, applespi->gpe);
}

static u32 applespi_notify(acpi_handle gpe_device, u32 gpe, void *context)
{
        struct applespi_data *applespi = context;
        int sts;
        unsigned long flags;

        trace_applespi_irq_received(ET_RD_IRQ, PT_READ);

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        if (!applespi->suspended) {
                sts = applespi_async(applespi, &applespi->rd_m,
                                     applespi_async_read_complete);
                if (sts)
                        dev_warn(&applespi->spi->dev,
                                 "Error queueing async read to device: %d\n",
                                 sts);
                else
                        applespi->read_active = true;
        }

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);

        return ACPI_INTERRUPT_HANDLED;
}

static int applespi_get_saved_bl_level(struct applespi_data *applespi)
{
        struct efivar_entry *efivar_entry;
        u16 efi_data = 0;
        unsigned long efi_data_len;
        int sts;

        efivar_entry = kmalloc(sizeof(*efivar_entry), GFP_KERNEL);
        if (!efivar_entry)
                return -ENOMEM;

        memcpy(efivar_entry->var.VariableName, EFI_BL_LEVEL_NAME,
               sizeof(EFI_BL_LEVEL_NAME));
        efivar_entry->var.VendorGuid = EFI_BL_LEVEL_GUID;
        efi_data_len = sizeof(efi_data);

        sts = efivar_entry_get(efivar_entry, NULL, &efi_data_len, &efi_data);
        if (sts && sts != -ENOENT)
                dev_warn(&applespi->spi->dev,
                         "Error getting backlight level from EFI vars: %d\n",
                         sts);

        kfree(efivar_entry);

        return sts ? sts : efi_data;
}

static void applespi_save_bl_level(struct applespi_data *applespi,
                                   unsigned int level)
{
        efi_guid_t efi_guid;
        u32 efi_attr;
        unsigned long efi_data_len;
        u16 efi_data;
        int sts;

        /* Save keyboard backlight level */
        efi_guid = EFI_BL_LEVEL_GUID;
        efi_data = (u16)level;
        efi_data_len = sizeof(efi_data);
        efi_attr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS |
                   EFI_VARIABLE_RUNTIME_ACCESS;

        sts = efivar_entry_set_safe((efi_char16_t *)EFI_BL_LEVEL_NAME, efi_guid,
                                    efi_attr, true, efi_data_len, &efi_data);
        if (sts)
                dev_warn(&applespi->spi->dev,
                         "Error saving backlight level to EFI vars: %d\n", sts);
}

static int applespi_probe(struct spi_device *spi)
{
        struct applespi_data *applespi;
        acpi_handle spi_handle = ACPI_HANDLE(&spi->dev);
        acpi_status acpi_sts;
        int sts, i;
        unsigned long long gpe, usb_status;

        /* check if the USB interface is present and enabled already */
        acpi_sts = acpi_evaluate_integer(spi_handle, "UIST", NULL, &usb_status);
        if (ACPI_SUCCESS(acpi_sts) && usb_status) {
                /* let the USB driver take over instead */
                dev_info(&spi->dev, "USB interface already enabled\n");
                return -ENODEV;
        }

        /* allocate driver data */
        applespi = devm_kzalloc(&spi->dev, sizeof(*applespi), GFP_KERNEL);
        if (!applespi)
                return -ENOMEM;

        applespi->spi = spi;

        INIT_WORK(&applespi->work, applespi_worker);

        /* store the driver data */
        spi_set_drvdata(spi, applespi);

        /* create our buffers */
        applespi->tx_buffer = devm_kmalloc(&spi->dev, APPLESPI_PACKET_SIZE,
                                           GFP_KERNEL);
        applespi->tx_status = devm_kmalloc(&spi->dev, APPLESPI_STATUS_SIZE,
                                           GFP_KERNEL);
        applespi->rx_buffer = devm_kmalloc(&spi->dev, APPLESPI_PACKET_SIZE,
                                           GFP_KERNEL);
        applespi->msg_buf = devm_kmalloc_array(&spi->dev, MAX_PKTS_PER_MSG,
                                               APPLESPI_PACKET_SIZE,
                                               GFP_KERNEL);

        if (!applespi->tx_buffer || !applespi->tx_status ||
            !applespi->rx_buffer || !applespi->msg_buf)
                return -ENOMEM;

        /* set up our spi messages */
        applespi_setup_read_txfrs(applespi);
        applespi_setup_write_txfrs(applespi);

        /* cache ACPI method handles */
        acpi_sts = acpi_get_handle(spi_handle, "SIEN", &applespi->sien);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev,
                        "Failed to get SIEN ACPI method handle: %s\n",
                        acpi_format_exception(acpi_sts));
                return -ENODEV;
        }

        acpi_sts = acpi_get_handle(spi_handle, "SIST", &applespi->sist);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev,
                        "Failed to get SIST ACPI method handle: %s\n",
                        acpi_format_exception(acpi_sts));
                return -ENODEV;
        }

        /* switch on the SPI interface */
        sts = applespi_setup_spi(applespi);
        if (sts)
                return sts;

        sts = applespi_enable_spi(applespi);
        if (sts)
                return sts;

        /* setup the keyboard input dev */
        applespi->keyboard_input_dev = devm_input_allocate_device(&spi->dev);

        if (!applespi->keyboard_input_dev)
                return -ENOMEM;

        applespi->keyboard_input_dev->name = "Apple SPI Keyboard";
        applespi->keyboard_input_dev->phys = "applespi/input0";
        applespi->keyboard_input_dev->dev.parent = &spi->dev;
        applespi->keyboard_input_dev->id.bustype = BUS_SPI;

        applespi->keyboard_input_dev->evbit[0] =
                        BIT_MASK(EV_KEY) | BIT_MASK(EV_LED) | BIT_MASK(EV_REP);
        applespi->keyboard_input_dev->ledbit[0] = BIT_MASK(LED_CAPSL);

        input_set_drvdata(applespi->keyboard_input_dev, applespi);
        applespi->keyboard_input_dev->event = applespi_event;

        for (i = 0; i < ARRAY_SIZE(applespi_scancodes); i++)
                if (applespi_scancodes[i])
                        input_set_capability(applespi->keyboard_input_dev,
                                             EV_KEY, applespi_scancodes[i]);

        for (i = 0; i < ARRAY_SIZE(applespi_controlcodes); i++)
                if (applespi_controlcodes[i])
                        input_set_capability(applespi->keyboard_input_dev,
                                             EV_KEY, applespi_controlcodes[i]);

        for (i = 0; i < ARRAY_SIZE(applespi_fn_codes); i++)
                if (applespi_fn_codes[i].to)
                        input_set_capability(applespi->keyboard_input_dev,
                                             EV_KEY, applespi_fn_codes[i].to);

        input_set_capability(applespi->keyboard_input_dev, EV_KEY, KEY_FN);

        sts = input_register_device(applespi->keyboard_input_dev);
        if (sts) {
                dev_err(&applespi->spi->dev,
                        "Unable to register keyboard input device (%d)\n", sts);
                return -ENODEV;
        }

        /*
         * The applespi device doesn't send interrupts normally (as is described
         * in its DSDT), but rather seems to use ACPI GPEs.
         */
        acpi_sts = acpi_evaluate_integer(spi_handle, "_GPE", NULL, &gpe);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev,
                        "Failed to obtain GPE for SPI slave device: %s\n",
                        acpi_format_exception(acpi_sts));
                return -ENODEV;
        }
        applespi->gpe = (int)gpe;

        acpi_sts = acpi_install_gpe_handler(NULL, applespi->gpe,
                                            ACPI_GPE_LEVEL_TRIGGERED,
                                            applespi_notify, applespi);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev,
                        "Failed to install GPE handler for GPE %d: %s\n",
                        applespi->gpe, acpi_format_exception(acpi_sts));
                return -ENODEV;
        }

        applespi->suspended = false;

        acpi_sts = acpi_enable_gpe(NULL, applespi->gpe);
        if (ACPI_FAILURE(acpi_sts)) {
                dev_err(&applespi->spi->dev,
                        "Failed to enable GPE handler for GPE %d: %s\n",
                        applespi->gpe, acpi_format_exception(acpi_sts));
                acpi_remove_gpe_handler(NULL, applespi->gpe, applespi_notify);
                return -ENODEV;
        }

        /* trigger touchpad setup */
        applespi_init(applespi, false);

        /*
         * By default this device is not enabled for wakeup; but USB keyboards
         * generally are, so the expectation is that by default the keyboard
         * will wake the system.
         */
        device_wakeup_enable(&spi->dev);

        /* set up keyboard-backlight */
        sts = applespi_get_saved_bl_level(applespi);
        if (sts >= 0)
                applespi_set_bl_level(&applespi->backlight_info, sts);

        applespi->backlight_info.name            = "spi::kbd_backlight";
        applespi->backlight_info.default_trigger = "kbd-backlight";
        applespi->backlight_info.brightness_set  = applespi_set_bl_level;

        sts = devm_led_classdev_register(&spi->dev, &applespi->backlight_info);
        if (sts)
                dev_warn(&applespi->spi->dev,
                         "Unable to register keyboard backlight class dev (%d)\n",
                         sts);

        /* set up debugfs entries for touchpad dimensions logging */
        applespi->debugfs_root = debugfs_create_dir("applespi", NULL);

        debugfs_create_bool("enable_tp_dim", 0600, applespi->debugfs_root,
                            &applespi->debug_tp_dim);

        debugfs_create_file("tp_dim", 0400, applespi->debugfs_root, applespi,
                            &applespi_tp_dim_fops);

        return 0;
}

static void applespi_drain_writes(struct applespi_data *applespi)
{
        unsigned long flags;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        applespi->drain = true;
        wait_event_lock_irq(applespi->drain_complete, !applespi->write_active,
                            applespi->cmd_msg_lock);

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
}

static void applespi_drain_reads(struct applespi_data *applespi)
{
        unsigned long flags;

        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        wait_event_lock_irq(applespi->drain_complete, !applespi->read_active,
                            applespi->cmd_msg_lock);

        applespi->suspended = true;

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
}

static int applespi_remove(struct spi_device *spi)
{
        struct applespi_data *applespi = spi_get_drvdata(spi);

        applespi_drain_writes(applespi);

        acpi_disable_gpe(NULL, applespi->gpe);
        acpi_remove_gpe_handler(NULL, applespi->gpe, applespi_notify);
        device_wakeup_disable(&spi->dev);

        applespi_drain_reads(applespi);

        debugfs_remove_recursive(applespi->debugfs_root);

        return 0;
}

static void applespi_shutdown(struct spi_device *spi)
{
        struct applespi_data *applespi = spi_get_drvdata(spi);

        applespi_save_bl_level(applespi, applespi->have_bl_level);
}

static int applespi_poweroff_late(struct device *dev)
{
        struct spi_device *spi = to_spi_device(dev);
        struct applespi_data *applespi = spi_get_drvdata(spi);

        applespi_save_bl_level(applespi, applespi->have_bl_level);

        return 0;
}

static int __maybe_unused applespi_suspend(struct device *dev)
{
        struct spi_device *spi = to_spi_device(dev);
        struct applespi_data *applespi = spi_get_drvdata(spi);
        acpi_status acpi_sts;
        int sts;

        /* turn off caps-lock - it'll stay on otherwise */
        sts = applespi_set_capsl_led(applespi, false);
        if (sts)
                dev_warn(&applespi->spi->dev,
                         "Failed to turn off caps-lock led (%d)\n", sts);

        applespi_drain_writes(applespi);

        /* disable the interrupt */
        acpi_sts = acpi_disable_gpe(NULL, applespi->gpe);
        if (ACPI_FAILURE(acpi_sts))
                dev_err(&applespi->spi->dev,
                        "Failed to disable GPE handler for GPE %d: %s\n",
                        applespi->gpe, acpi_format_exception(acpi_sts));

        applespi_drain_reads(applespi);

        return 0;
}

static int __maybe_unused applespi_resume(struct device *dev)
{
        struct spi_device *spi = to_spi_device(dev);
        struct applespi_data *applespi = spi_get_drvdata(spi);
        acpi_status acpi_sts;
        unsigned long flags;

        /* ensure our flags and state reflect a newly resumed device */
        spin_lock_irqsave(&applespi->cmd_msg_lock, flags);

        applespi->drain = false;
        applespi->have_cl_led_on = false;
        applespi->have_bl_level = 0;
        applespi->cmd_msg_queued = 0;
        applespi->read_active = false;
        applespi->write_active = false;

        applespi->suspended = false;

        spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);

        /* switch on the SPI interface */
        applespi_enable_spi(applespi);

        /* re-enable the interrupt */
        acpi_sts = acpi_enable_gpe(NULL, applespi->gpe);
        if (ACPI_FAILURE(acpi_sts))
                dev_err(&applespi->spi->dev,
                        "Failed to re-enable GPE handler for GPE %d: %s\n",
                        applespi->gpe, acpi_format_exception(acpi_sts));

        /* switch the touchpad into multitouch mode */
        applespi_init(applespi, true);

        return 0;
}

static const struct acpi_device_id applespi_acpi_match[] = {
        { "APP000D", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, applespi_acpi_match);

static const struct dev_pm_ops applespi_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(applespi_suspend, applespi_resume)
        .poweroff_late  = applespi_poweroff_late,
};

static struct spi_driver applespi_driver = {
        .driver         = {
                .name                   = "applespi",
                .acpi_match_table       = applespi_acpi_match,
                .pm                     = &applespi_pm_ops,
        },
        .probe          = applespi_probe,
        .remove         = applespi_remove,
        .shutdown       = applespi_shutdown,
};

module_spi_driver(applespi_driver)

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MacBook(Pro) SPI Keyboard/Touchpad driver");
MODULE_AUTHOR("Federico Lorenzi");
MODULE_AUTHOR("Ronald Tschalär");