linux/drivers/platform/x86/apple-gmux.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Gmux driver for Apple laptops
   4 *
   5 *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
   6 *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
   7 *  Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
   8 */
   9
  10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12#include <linux/module.h>
  13#include <linux/kernel.h>
  14#include <linux/init.h>
  15#include <linux/backlight.h>
  16#include <linux/acpi.h>
  17#include <linux/pnp.h>
  18#include <linux/apple_bl.h>
  19#include <linux/apple-gmux.h>
  20#include <linux/slab.h>
  21#include <linux/delay.h>
  22#include <linux/pci.h>
  23#include <linux/vga_switcheroo.h>
  24#include <acpi/video.h>
  25#include <asm/io.h>
  26
  27/**
  28 * DOC: Overview
  29 *
  30 * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
  31 * A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.
  32 *
  33 * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
  34 * dual GPUs but no built-in display.)
  35 *
  36 * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
  37 * accessed differently depending on the microcontroller: Driver functions
  38 * to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux
  39 * are infixed ``_index_``.
  40 *
  41 * .. _Lattice XP2:
  42 *     http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
  43 * .. _Renesas R4F2113:
  44 *     http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
  45 */
  46
  47struct apple_gmux_data {
  48        unsigned long iostart;
  49        unsigned long iolen;
  50        bool indexed;
  51        struct mutex index_lock;
  52
  53        struct backlight_device *bdev;
  54
  55        /* switcheroo data */
  56        acpi_handle dhandle;
  57        int gpe;
  58        bool external_switchable;
  59        enum vga_switcheroo_client_id switch_state_display;
  60        enum vga_switcheroo_client_id switch_state_ddc;
  61        enum vga_switcheroo_client_id switch_state_external;
  62        enum vga_switcheroo_state power_state;
  63        struct completion powerchange_done;
  64};
  65
  66static struct apple_gmux_data *apple_gmux_data;
  67
  68/*
  69 * gmux port offsets. Many of these are not yet used, but may be in the
  70 * future, and it's useful to have them documented here anyhow.
  71 */
  72#define GMUX_PORT_VERSION_MAJOR         0x04
  73#define GMUX_PORT_VERSION_MINOR         0x05
  74#define GMUX_PORT_VERSION_RELEASE       0x06
  75#define GMUX_PORT_SWITCH_DISPLAY        0x10
  76#define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
  77#define GMUX_PORT_INTERRUPT_ENABLE      0x14
  78#define GMUX_PORT_INTERRUPT_STATUS      0x16
  79#define GMUX_PORT_SWITCH_DDC            0x28
  80#define GMUX_PORT_SWITCH_EXTERNAL       0x40
  81#define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
  82#define GMUX_PORT_DISCRETE_POWER        0x50
  83#define GMUX_PORT_MAX_BRIGHTNESS        0x70
  84#define GMUX_PORT_BRIGHTNESS            0x74
  85#define GMUX_PORT_VALUE                 0xc2
  86#define GMUX_PORT_READ                  0xd0
  87#define GMUX_PORT_WRITE                 0xd4
  88
  89#define GMUX_MIN_IO_LEN                 (GMUX_PORT_BRIGHTNESS + 4)
  90
  91#define GMUX_INTERRUPT_ENABLE           0xff
  92#define GMUX_INTERRUPT_DISABLE          0x00
  93
  94#define GMUX_INTERRUPT_STATUS_ACTIVE    0
  95#define GMUX_INTERRUPT_STATUS_DISPLAY   (1 << 0)
  96#define GMUX_INTERRUPT_STATUS_POWER     (1 << 2)
  97#define GMUX_INTERRUPT_STATUS_HOTPLUG   (1 << 3)
  98
  99#define GMUX_BRIGHTNESS_MASK            0x00ffffff
 100#define GMUX_MAX_BRIGHTNESS             GMUX_BRIGHTNESS_MASK
 101
 102static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
 103{
 104        return inb(gmux_data->iostart + port);
 105}
 106
 107static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
 108                               u8 val)
 109{
 110        outb(val, gmux_data->iostart + port);
 111}
 112
 113static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
 114{
 115        return inl(gmux_data->iostart + port);
 116}
 117
 118static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
 119                             u32 val)
 120{
 121        int i;
 122        u8 tmpval;
 123
 124        for (i = 0; i < 4; i++) {
 125                tmpval = (val >> (i * 8)) & 0xff;
 126                outb(tmpval, gmux_data->iostart + port + i);
 127        }
 128}
 129
 130static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
 131{
 132        int i = 200;
 133        u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
 134
 135        while (i && (gwr & 0x01)) {
 136                inb(gmux_data->iostart + GMUX_PORT_READ);
 137                gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
 138                udelay(100);
 139                i--;
 140        }
 141
 142        return !!i;
 143}
 144
 145static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
 146{
 147        int i = 200;
 148        u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
 149
 150        while (i && !(gwr & 0x01)) {
 151                gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
 152                udelay(100);
 153                i--;
 154        }
 155
 156        if (gwr & 0x01)
 157                inb(gmux_data->iostart + GMUX_PORT_READ);
 158
 159        return !!i;
 160}
 161
 162static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
 163{
 164        u8 val;
 165
 166        mutex_lock(&gmux_data->index_lock);
 167        gmux_index_wait_ready(gmux_data);
 168        outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 169        gmux_index_wait_complete(gmux_data);
 170        val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
 171        mutex_unlock(&gmux_data->index_lock);
 172
 173        return val;
 174}
 175
 176static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
 177                              u8 val)
 178{
 179        mutex_lock(&gmux_data->index_lock);
 180        outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
 181        gmux_index_wait_ready(gmux_data);
 182        outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
 183        gmux_index_wait_complete(gmux_data);
 184        mutex_unlock(&gmux_data->index_lock);
 185}
 186
 187static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
 188{
 189        u32 val;
 190
 191        mutex_lock(&gmux_data->index_lock);
 192        gmux_index_wait_ready(gmux_data);
 193        outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 194        gmux_index_wait_complete(gmux_data);
 195        val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
 196        mutex_unlock(&gmux_data->index_lock);
 197
 198        return val;
 199}
 200
 201static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
 202                               u32 val)
 203{
 204        int i;
 205        u8 tmpval;
 206
 207        mutex_lock(&gmux_data->index_lock);
 208
 209        for (i = 0; i < 4; i++) {
 210                tmpval = (val >> (i * 8)) & 0xff;
 211                outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
 212        }
 213
 214        gmux_index_wait_ready(gmux_data);
 215        outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
 216        gmux_index_wait_complete(gmux_data);
 217        mutex_unlock(&gmux_data->index_lock);
 218}
 219
 220static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
 221{
 222        if (gmux_data->indexed)
 223                return gmux_index_read8(gmux_data, port);
 224        else
 225                return gmux_pio_read8(gmux_data, port);
 226}
 227
 228static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
 229{
 230        if (gmux_data->indexed)
 231                gmux_index_write8(gmux_data, port, val);
 232        else
 233                gmux_pio_write8(gmux_data, port, val);
 234}
 235
 236static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
 237{
 238        if (gmux_data->indexed)
 239                return gmux_index_read32(gmux_data, port);
 240        else
 241                return gmux_pio_read32(gmux_data, port);
 242}
 243
 244static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
 245                             u32 val)
 246{
 247        if (gmux_data->indexed)
 248                gmux_index_write32(gmux_data, port, val);
 249        else
 250                gmux_pio_write32(gmux_data, port, val);
 251}
 252
 253static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
 254{
 255        u16 val;
 256
 257        outb(0xaa, gmux_data->iostart + 0xcc);
 258        outb(0x55, gmux_data->iostart + 0xcd);
 259        outb(0x00, gmux_data->iostart + 0xce);
 260
 261        val = inb(gmux_data->iostart + 0xcc) |
 262                (inb(gmux_data->iostart + 0xcd) << 8);
 263
 264        if (val == 0x55aa)
 265                return true;
 266
 267        return false;
 268}
 269
 270/**
 271 * DOC: Backlight control
 272 *
 273 * On single GPU MacBooks, the PWM signal for the backlight is generated by
 274 * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
 275 * to conserve energy. Hence the PWM signal needs to be generated by a separate
 276 * backlight driver which is controlled by gmux. The earliest generation
 277 * MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models
 278 * use a `TI LP8545`_.
 279 *
 280 * .. _TI LP8543: http://www.ti.com/lit/ds/symlink/lp8543.pdf
 281 * .. _TI LP8545: http://www.ti.com/lit/ds/symlink/lp8545.pdf
 282 */
 283
 284static int gmux_get_brightness(struct backlight_device *bd)
 285{
 286        struct apple_gmux_data *gmux_data = bl_get_data(bd);
 287        return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
 288               GMUX_BRIGHTNESS_MASK;
 289}
 290
 291static int gmux_update_status(struct backlight_device *bd)
 292{
 293        struct apple_gmux_data *gmux_data = bl_get_data(bd);
 294        u32 brightness = bd->props.brightness;
 295
 296        if (bd->props.state & BL_CORE_SUSPENDED)
 297                return 0;
 298
 299        gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
 300
 301        return 0;
 302}
 303
 304static const struct backlight_ops gmux_bl_ops = {
 305        .options = BL_CORE_SUSPENDRESUME,
 306        .get_brightness = gmux_get_brightness,
 307        .update_status = gmux_update_status,
 308};
 309
 310/**
 311 * DOC: Graphics mux
 312 *
 313 * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
 314 * either of them to the panel. One of the tricks gmux has up its sleeve is
 315 * to lengthen the blanking interval of its output during a switch to
 316 * synchronize it with the GPU switched to. This allows for a flicker-free
 317 * switch that is imperceptible by the user (`US 8,687,007 B2`_).
 318 *
 319 * On retinas, muxing is no longer done by gmux itself, but by a separate
 320 * chip which is controlled by gmux. The chip is triple sourced, it is
 321 * either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.
 322 * The panel is driven with eDP instead of LVDS since the pixel clock
 323 * required for retina resolution exceeds LVDS' limits.
 324 *
 325 * Pre-retinas are able to switch the panel's DDC pins separately.
 326 * This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.
 327 * The inactive GPU can thus probe the panel's EDID without switching over
 328 * the entire panel. Retinas lack this functionality as the chips used for
 329 * eDP muxing are incapable of switching the AUX channel separately (see
 330 * the linked data sheets, Pericom would be capable but this is unused).
 331 * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
 332 * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
 333 * set up the output with link parameters pre-calibrated by the active GPU.
 334 *
 335 * The external DP port is only fully switchable on the first two unibody
 336 * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
 337 * `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the
 338 * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
 339 *
 340 * The following MacBook Pro generations replaced the external DP port with a
 341 * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
 342 * connecting it either to the discrete GPU or the Thunderbolt controller.
 343 * Oddly enough, while the full port is no longer switchable, AUX and HPD
 344 * are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas
 345 * MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the
 346 * control of gmux. Since the integrated GPU is missing the main link,
 347 * external displays appear to it as phantoms which fail to link-train.
 348 *
 349 * gmux receives the HPD signal of all display connectors and sends an
 350 * interrupt on hotplug. On generations which cannot switch external ports,
 351 * the discrete GPU can then be woken to drive the newly connected display.
 352 * The ability to switch AUX on these generations could be used to improve
 353 * reliability of hotplug detection by having the integrated GPU poll the
 354 * ports while the discrete GPU is asleep, but currently we do not make use
 355 * of this feature.
 356 *
 357 * Our switching policy for the external port is that on those generations
 358 * which are able to switch it fully, the port is switched together with the
 359 * panel when IGD / DIS commands are issued to vga_switcheroo. It is thus
 360 * possible to drive e.g. a beamer on battery power with the integrated GPU.
 361 * The user may manually switch to the discrete GPU if more performance is
 362 * needed.
 363 *
 364 * On all newer generations, the external port can only be driven by the
 365 * discrete GPU. If a display is plugged in while the panel is switched to
 366 * the integrated GPU, *both* GPUs will be in use for maximum performance.
 367 * To decrease power consumption, the user may manually switch to the
 368 * discrete GPU, thereby suspending the integrated GPU.
 369 *
 370 * gmux' initial switch state on bootup is user configurable via the EFI
 371 * variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,
 372 * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
 373 * switch the panel and the external DP connector and allocates a framebuffer
 374 * for the selected GPU.
 375 *
 376 * .. _US 8,687,007 B2: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
 377 * .. _NXP CBTL06141:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
 378 * .. _NXP CBTL06142:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
 379 * .. _TI HD3SS212:     http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
 380 * .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
 381 * .. _TI SN74LV4066A:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
 382 * .. _NXP CBTL03062:   http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
 383 * .. _TI TS3DS10224:   http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
 384 */
 385
 386static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)
 387{
 388        if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DDC) == 1)
 389                gmux_data->switch_state_ddc = VGA_SWITCHEROO_IGD;
 390        else
 391                gmux_data->switch_state_ddc = VGA_SWITCHEROO_DIS;
 392
 393        if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
 394                gmux_data->switch_state_display = VGA_SWITCHEROO_IGD;
 395        else
 396                gmux_data->switch_state_display = VGA_SWITCHEROO_DIS;
 397
 398        if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL) == 2)
 399                gmux_data->switch_state_external = VGA_SWITCHEROO_IGD;
 400        else
 401                gmux_data->switch_state_external = VGA_SWITCHEROO_DIS;
 402}
 403
 404static void gmux_write_switch_state(struct apple_gmux_data *gmux_data)
 405{
 406        if (gmux_data->switch_state_ddc == VGA_SWITCHEROO_IGD)
 407                gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 1);
 408        else
 409                gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 2);
 410
 411        if (gmux_data->switch_state_display == VGA_SWITCHEROO_IGD)
 412                gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
 413        else
 414                gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
 415
 416        if (gmux_data->switch_state_external == VGA_SWITCHEROO_IGD)
 417                gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
 418        else
 419                gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
 420}
 421
 422static int gmux_switchto(enum vga_switcheroo_client_id id)
 423{
 424        apple_gmux_data->switch_state_ddc = id;
 425        apple_gmux_data->switch_state_display = id;
 426        if (apple_gmux_data->external_switchable)
 427                apple_gmux_data->switch_state_external = id;
 428
 429        gmux_write_switch_state(apple_gmux_data);
 430
 431        return 0;
 432}
 433
 434static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
 435{
 436        enum vga_switcheroo_client_id old_ddc_owner =
 437                apple_gmux_data->switch_state_ddc;
 438
 439        if (id == old_ddc_owner)
 440                return id;
 441
 442        pr_debug("Switching DDC from %d to %d\n", old_ddc_owner, id);
 443        apple_gmux_data->switch_state_ddc = id;
 444
 445        if (id == VGA_SWITCHEROO_IGD)
 446                gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
 447        else
 448                gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
 449
 450        return old_ddc_owner;
 451}
 452
 453/**
 454 * DOC: Power control
 455 *
 456 * gmux is able to cut power to the discrete GPU. It automatically takes care
 457 * of the correct sequence to tear down and bring up the power rails for
 458 * core voltage, VRAM and PCIe.
 459 */
 460
 461static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
 462                                   enum vga_switcheroo_state state)
 463{
 464        reinit_completion(&gmux_data->powerchange_done);
 465
 466        if (state == VGA_SWITCHEROO_ON) {
 467                gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
 468                gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
 469                pr_debug("Discrete card powered up\n");
 470        } else {
 471                gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
 472                gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
 473                pr_debug("Discrete card powered down\n");
 474        }
 475
 476        gmux_data->power_state = state;
 477
 478        if (gmux_data->gpe >= 0 &&
 479            !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
 480                                                       msecs_to_jiffies(200)))
 481                pr_warn("Timeout waiting for gmux switch to complete\n");
 482
 483        return 0;
 484}
 485
 486static int gmux_set_power_state(enum vga_switcheroo_client_id id,
 487                                enum vga_switcheroo_state state)
 488{
 489        if (id == VGA_SWITCHEROO_IGD)
 490                return 0;
 491
 492        return gmux_set_discrete_state(apple_gmux_data, state);
 493}
 494
 495static enum vga_switcheroo_client_id gmux_get_client_id(struct pci_dev *pdev)
 496{
 497        /*
 498         * Early Macbook Pros with switchable graphics use nvidia
 499         * integrated graphics. Hardcode that the 9400M is integrated.
 500         */
 501        if (pdev->vendor == PCI_VENDOR_ID_INTEL)
 502                return VGA_SWITCHEROO_IGD;
 503        else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
 504                 pdev->device == 0x0863)
 505                return VGA_SWITCHEROO_IGD;
 506        else
 507                return VGA_SWITCHEROO_DIS;
 508}
 509
 510static const struct vga_switcheroo_handler gmux_handler_indexed = {
 511        .switchto = gmux_switchto,
 512        .power_state = gmux_set_power_state,
 513        .get_client_id = gmux_get_client_id,
 514};
 515
 516static const struct vga_switcheroo_handler gmux_handler_classic = {
 517        .switchto = gmux_switchto,
 518        .switch_ddc = gmux_switch_ddc,
 519        .power_state = gmux_set_power_state,
 520        .get_client_id = gmux_get_client_id,
 521};
 522
 523/**
 524 * DOC: Interrupt
 525 *
 526 * gmux is also connected to a GPIO pin of the southbridge and thereby is able
 527 * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
 528 * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
 529 * The GPE merely signals that an interrupt occurred, the actual type of event
 530 * is identified by reading a gmux register.
 531 */
 532
 533static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
 534{
 535        gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
 536                    GMUX_INTERRUPT_DISABLE);
 537}
 538
 539static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
 540{
 541        gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
 542                    GMUX_INTERRUPT_ENABLE);
 543}
 544
 545static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
 546{
 547        return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
 548}
 549
 550static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
 551{
 552        u8 status;
 553
 554        /* to clear interrupts write back current status */
 555        status = gmux_interrupt_get_status(gmux_data);
 556        gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
 557}
 558
 559static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
 560{
 561        u8 status;
 562        struct pnp_dev *pnp = (struct pnp_dev *)context;
 563        struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
 564
 565        status = gmux_interrupt_get_status(gmux_data);
 566        gmux_disable_interrupts(gmux_data);
 567        pr_debug("Notify handler called: status %d\n", status);
 568
 569        gmux_clear_interrupts(gmux_data);
 570        gmux_enable_interrupts(gmux_data);
 571
 572        if (status & GMUX_INTERRUPT_STATUS_POWER)
 573                complete(&gmux_data->powerchange_done);
 574}
 575
 576static int gmux_suspend(struct device *dev)
 577{
 578        struct pnp_dev *pnp = to_pnp_dev(dev);
 579        struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
 580
 581        gmux_disable_interrupts(gmux_data);
 582        return 0;
 583}
 584
 585static int gmux_resume(struct device *dev)
 586{
 587        struct pnp_dev *pnp = to_pnp_dev(dev);
 588        struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
 589
 590        gmux_enable_interrupts(gmux_data);
 591        gmux_write_switch_state(gmux_data);
 592        if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
 593                gmux_set_discrete_state(gmux_data, gmux_data->power_state);
 594        return 0;
 595}
 596
 597static int is_thunderbolt(struct device *dev, void *data)
 598{
 599        return to_pci_dev(dev)->is_thunderbolt;
 600}
 601
 602static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 603{
 604        struct apple_gmux_data *gmux_data;
 605        struct resource *res;
 606        struct backlight_properties props;
 607        struct backlight_device *bdev;
 608        u8 ver_major, ver_minor, ver_release;
 609        int ret = -ENXIO;
 610        acpi_status status;
 611        unsigned long long gpe;
 612
 613        if (apple_gmux_data)
 614                return -EBUSY;
 615
 616        gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
 617        if (!gmux_data)
 618                return -ENOMEM;
 619        pnp_set_drvdata(pnp, gmux_data);
 620
 621        res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
 622        if (!res) {
 623                pr_err("Failed to find gmux I/O resource\n");
 624                goto err_free;
 625        }
 626
 627        gmux_data->iostart = res->start;
 628        gmux_data->iolen = res->end - res->start;
 629
 630        if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
 631                pr_err("gmux I/O region too small (%lu < %u)\n",
 632                       gmux_data->iolen, GMUX_MIN_IO_LEN);
 633                goto err_free;
 634        }
 635
 636        if (!request_region(gmux_data->iostart, gmux_data->iolen,
 637                            "Apple gmux")) {
 638                pr_err("gmux I/O already in use\n");
 639                goto err_free;
 640        }
 641
 642        /*
 643         * Invalid version information may indicate either that the gmux
 644         * device isn't present or that it's a new one that uses indexed
 645         * io
 646         */
 647
 648        ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
 649        ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
 650        ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
 651        if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
 652                if (gmux_is_indexed(gmux_data)) {
 653                        u32 version;
 654                        mutex_init(&gmux_data->index_lock);
 655                        gmux_data->indexed = true;
 656                        version = gmux_read32(gmux_data,
 657                                GMUX_PORT_VERSION_MAJOR);
 658                        ver_major = (version >> 24) & 0xff;
 659                        ver_minor = (version >> 16) & 0xff;
 660                        ver_release = (version >> 8) & 0xff;
 661                } else {
 662                        pr_info("gmux device not present\n");
 663                        ret = -ENODEV;
 664                        goto err_release;
 665                }
 666        }
 667        pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
 668                ver_release, (gmux_data->indexed ? "indexed" : "classic"));
 669
 670        memset(&props, 0, sizeof(props));
 671        props.type = BACKLIGHT_PLATFORM;
 672        props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
 673
 674        /*
 675         * Currently it's assumed that the maximum brightness is less than
 676         * 2^24 for compatibility with old gmux versions. Cap the max
 677         * brightness at this value, but print a warning if the hardware
 678         * reports something higher so that it can be fixed.
 679         */
 680        if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
 681                props.max_brightness = GMUX_MAX_BRIGHTNESS;
 682
 683        bdev = backlight_device_register("gmux_backlight", &pnp->dev,
 684                                         gmux_data, &gmux_bl_ops, &props);
 685        if (IS_ERR(bdev)) {
 686                ret = PTR_ERR(bdev);
 687                goto err_release;
 688        }
 689
 690        gmux_data->bdev = bdev;
 691        bdev->props.brightness = gmux_get_brightness(bdev);
 692        backlight_update_status(bdev);
 693
 694        /*
 695         * The backlight situation on Macs is complicated. If the gmux is
 696         * present it's the best choice, because it always works for
 697         * backlight control and supports more levels than other options.
 698         * Disable the other backlight choices.
 699         */
 700        acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
 701        apple_bl_unregister();
 702
 703        gmux_data->power_state = VGA_SWITCHEROO_ON;
 704
 705        gmux_data->dhandle = ACPI_HANDLE(&pnp->dev);
 706        if (!gmux_data->dhandle) {
 707                pr_err("Cannot find acpi handle for pnp device %s\n",
 708                       dev_name(&pnp->dev));
 709                ret = -ENODEV;
 710                goto err_notify;
 711        }
 712
 713        status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
 714        if (ACPI_SUCCESS(status)) {
 715                gmux_data->gpe = (int)gpe;
 716
 717                status = acpi_install_notify_handler(gmux_data->dhandle,
 718                                                     ACPI_DEVICE_NOTIFY,
 719                                                     &gmux_notify_handler, pnp);
 720                if (ACPI_FAILURE(status)) {
 721                        pr_err("Install notify handler failed: %s\n",
 722                               acpi_format_exception(status));
 723                        ret = -ENODEV;
 724                        goto err_notify;
 725                }
 726
 727                status = acpi_enable_gpe(NULL, gmux_data->gpe);
 728                if (ACPI_FAILURE(status)) {
 729                        pr_err("Cannot enable gpe: %s\n",
 730                               acpi_format_exception(status));
 731                        goto err_enable_gpe;
 732                }
 733        } else {
 734                pr_warn("No GPE found for gmux\n");
 735                gmux_data->gpe = -1;
 736        }
 737
 738        /*
 739         * If Thunderbolt is present, the external DP port is not fully
 740         * switchable. Force its AUX channel to the discrete GPU.
 741         */
 742        gmux_data->external_switchable =
 743                !bus_for_each_dev(&pci_bus_type, NULL, NULL, is_thunderbolt);
 744        if (!gmux_data->external_switchable)
 745                gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
 746
 747        apple_gmux_data = gmux_data;
 748        init_completion(&gmux_data->powerchange_done);
 749        gmux_enable_interrupts(gmux_data);
 750        gmux_read_switch_state(gmux_data);
 751
 752        /*
 753         * Retina MacBook Pros cannot switch the panel's AUX separately
 754         * and need eDP pre-calibration. They are distinguishable from
 755         * pre-retinas by having an "indexed" gmux.
 756         *
 757         * Pre-retina MacBook Pros can switch the panel's DDC separately.
 758         */
 759        if (gmux_data->indexed)
 760                ret = vga_switcheroo_register_handler(&gmux_handler_indexed,
 761                                              VGA_SWITCHEROO_NEEDS_EDP_CONFIG);
 762        else
 763                ret = vga_switcheroo_register_handler(&gmux_handler_classic,
 764                                              VGA_SWITCHEROO_CAN_SWITCH_DDC);
 765        if (ret) {
 766                pr_err("Failed to register vga_switcheroo handler\n");
 767                goto err_register_handler;
 768        }
 769
 770        return 0;
 771
 772err_register_handler:
 773        gmux_disable_interrupts(gmux_data);
 774        apple_gmux_data = NULL;
 775        if (gmux_data->gpe >= 0)
 776                acpi_disable_gpe(NULL, gmux_data->gpe);
 777err_enable_gpe:
 778        if (gmux_data->gpe >= 0)
 779                acpi_remove_notify_handler(gmux_data->dhandle,
 780                                           ACPI_DEVICE_NOTIFY,
 781                                           &gmux_notify_handler);
 782err_notify:
 783        backlight_device_unregister(bdev);
 784err_release:
 785        release_region(gmux_data->iostart, gmux_data->iolen);
 786err_free:
 787        kfree(gmux_data);
 788        return ret;
 789}
 790
 791static void gmux_remove(struct pnp_dev *pnp)
 792{
 793        struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
 794
 795        vga_switcheroo_unregister_handler();
 796        gmux_disable_interrupts(gmux_data);
 797        if (gmux_data->gpe >= 0) {
 798                acpi_disable_gpe(NULL, gmux_data->gpe);
 799                acpi_remove_notify_handler(gmux_data->dhandle,
 800                                           ACPI_DEVICE_NOTIFY,
 801                                           &gmux_notify_handler);
 802        }
 803
 804        backlight_device_unregister(gmux_data->bdev);
 805
 806        release_region(gmux_data->iostart, gmux_data->iolen);
 807        apple_gmux_data = NULL;
 808        kfree(gmux_data);
 809
 810        acpi_video_register();
 811        apple_bl_register();
 812}
 813
 814static const struct pnp_device_id gmux_device_ids[] = {
 815        {GMUX_ACPI_HID, 0},
 816        {"", 0}
 817};
 818
 819static const struct dev_pm_ops gmux_dev_pm_ops = {
 820        .suspend = gmux_suspend,
 821        .resume = gmux_resume,
 822};
 823
 824static struct pnp_driver gmux_pnp_driver = {
 825        .name           = "apple-gmux",
 826        .probe          = gmux_probe,
 827        .remove         = gmux_remove,
 828        .id_table       = gmux_device_ids,
 829        .driver         = {
 830                        .pm = &gmux_dev_pm_ops,
 831        },
 832};
 833
 834module_pnp_driver(gmux_pnp_driver);
 835MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
 836MODULE_DESCRIPTION("Apple Gmux Driver");
 837MODULE_LICENSE("GPL");
 838MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
 839