linux/drivers/platform/olpc/olpc-xo175-ec.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Driver for the OLPC XO-1.75 Embedded Controller.
   4 *
   5 * The EC protocol is documented at:
   6 * http://wiki.laptop.org/go/XO_1.75_HOST_to_EC_Protocol
   7 *
   8 * Copyright (C) 2010 One Laptop per Child Foundation.
   9 * Copyright (C) 2018 Lubomir Rintel <lkundrak@v3.sk>
  10 */
  11
  12#include <linux/completion.h>
  13#include <linux/ctype.h>
  14#include <linux/delay.h>
  15#include <linux/gpio/consumer.h>
  16#include <linux/input.h>
  17#include <linux/kfifo.h>
  18#include <linux/module.h>
  19#include <linux/olpc-ec.h>
  20#include <linux/platform_device.h>
  21#include <linux/power_supply.h>
  22#include <linux/reboot.h>
  23#include <linux/slab.h>
  24#include <linux/spinlock.h>
  25#include <linux/spi/spi.h>
  26
  27struct ec_cmd_t {
  28        u8 cmd;
  29        u8 bytes_returned;
  30};
  31
  32enum ec_chan_t {
  33        CHAN_NONE = 0,
  34        CHAN_SWITCH,
  35        CHAN_CMD_RESP,
  36        CHAN_KEYBOARD,
  37        CHAN_TOUCHPAD,
  38        CHAN_EVENT,
  39        CHAN_DEBUG,
  40        CHAN_CMD_ERROR,
  41};
  42
  43/*
  44 * EC events
  45 */
  46#define EVENT_AC_CHANGE                 1  /* AC plugged/unplugged */
  47#define EVENT_BATTERY_STATUS            2  /* Battery low/full/error/gone */
  48#define EVENT_BATTERY_CRITICAL          3  /* Battery critical voltage */
  49#define EVENT_BATTERY_SOC_CHANGE        4  /* 1% SOC Change */
  50#define EVENT_BATTERY_ERROR             5  /* Abnormal error, query for cause */
  51#define EVENT_POWER_PRESSED             6  /* Power button was pressed */
  52#define EVENT_POWER_PRESS_WAKE          7  /* Woken up with a power button */
  53#define EVENT_TIMED_HOST_WAKE           8  /* Host wake timer */
  54#define EVENT_OLS_HIGH_LIMIT            9  /* OLS crossed dark threshold */
  55#define EVENT_OLS_LOW_LIMIT             10 /* OLS crossed light threshold */
  56
  57/*
  58 * EC commands
  59 * (from http://dev.laptop.org/git/users/rsmith/ec-1.75/tree/ec_cmd.h)
  60 */
  61#define CMD_GET_API_VERSION             0x08 /* out: u8 */
  62#define CMD_READ_VOLTAGE                0x10 /* out: u16, *9.76/32, mV */
  63#define CMD_READ_CURRENT                0x11 /* out: s16, *15.625/120, mA */
  64#define CMD_READ_ACR                    0x12 /* out: s16, *6250/15, uAh */
  65#define CMD_READ_BATT_TEMPERATURE       0x13 /* out: u16, *100/256, deg C */
  66#define CMD_READ_AMBIENT_TEMPERATURE    0x14 /* unimplemented, no hardware */
  67#define CMD_READ_BATTERY_STATUS         0x15 /* out: u8, bitmask */
  68#define CMD_READ_SOC                    0x16 /* out: u8, percentage */
  69#define CMD_READ_GAUGE_ID               0x17 /* out: u8 * 8 */
  70#define CMD_READ_GAUGE_DATA             0x18 /* in: u8 addr, out: u8 data */
  71#define CMD_READ_BOARD_ID               0x19 /* out: u16 (platform id) */
  72#define CMD_READ_BATT_ERR_CODE          0x1f /* out: u8, error bitmask */
  73#define CMD_SET_DCON_POWER              0x26 /* in: u8 */
  74#define CMD_RESET_EC                    0x28 /* none */
  75#define CMD_READ_BATTERY_TYPE           0x2c /* out: u8 */
  76#define CMD_SET_AUTOWAK                 0x33 /* out: u8 */
  77#define CMD_SET_EC_WAKEUP_TIMER         0x36 /* in: u32, out: ? */
  78#define CMD_READ_EXT_SCI_MASK           0x37 /* ? */
  79#define CMD_WRITE_EXT_SCI_MASK          0x38 /* ? */
  80#define CMD_CLEAR_EC_WAKEUP_TIMER       0x39 /* none */
  81#define CMD_ENABLE_RUNIN_DISCHARGE      0x3B /* none */
  82#define CMD_DISABLE_RUNIN_DISCHARGE     0x3C /* none */
  83#define CMD_READ_MPPT_ACTIVE            0x3d /* out: u8 */
  84#define CMD_READ_MPPT_LIMIT             0x3e /* out: u8 */
  85#define CMD_SET_MPPT_LIMIT              0x3f /* in: u8 */
  86#define CMD_DISABLE_MPPT                0x40 /* none */
  87#define CMD_ENABLE_MPPT                 0x41 /* none */
  88#define CMD_READ_VIN                    0x42 /* out: u16 */
  89#define CMD_EXT_SCI_QUERY               0x43 /* ? */
  90#define RSP_KEYBOARD_DATA               0x48 /* ? */
  91#define RSP_TOUCHPAD_DATA               0x49 /* ? */
  92#define CMD_GET_FW_VERSION              0x4a /* out: u8 * 16 */
  93#define CMD_POWER_CYCLE                 0x4b /* none */
  94#define CMD_POWER_OFF                   0x4c /* none */
  95#define CMD_RESET_EC_SOFT               0x4d /* none */
  96#define CMD_READ_GAUGE_U16              0x4e /* ? */
  97#define CMD_ENABLE_MOUSE                0x4f /* ? */
  98#define CMD_ECHO                        0x52 /* in: u8 * 5, out: u8 * 5 */
  99#define CMD_GET_FW_DATE                 0x53 /* out: u8 * 16 */
 100#define CMD_GET_FW_USER                 0x54 /* out: u8 * 16 */
 101#define CMD_TURN_OFF_POWER              0x55 /* none (same as 0x4c) */
 102#define CMD_READ_OLS                    0x56 /* out: u16 */
 103#define CMD_OLS_SMT_LEDON               0x57 /* none */
 104#define CMD_OLS_SMT_LEDOFF              0x58 /* none */
 105#define CMD_START_OLS_ASSY              0x59 /* none */
 106#define CMD_STOP_OLS_ASSY               0x5a /* none */
 107#define CMD_OLS_SMTTEST_STOP            0x5b /* none */
 108#define CMD_READ_VIN_SCALED             0x5c /* out: u16 */
 109#define CMD_READ_BAT_MIN_W              0x5d /* out: u16 */
 110#define CMD_READ_BAR_MAX_W              0x5e /* out: u16 */
 111#define CMD_RESET_BAT_MINMAX_W          0x5f /* none */
 112#define CMD_READ_LOCATION               0x60 /* in: u16 addr, out: u8 data */
 113#define CMD_WRITE_LOCATION              0x61 /* in: u16 addr, u8 data */
 114#define CMD_KEYBOARD_CMD                0x62 /* in: u8, out: ? */
 115#define CMD_TOUCHPAD_CMD                0x63 /* in: u8, out: ? */
 116#define CMD_GET_FW_HASH                 0x64 /* out: u8 * 16 */
 117#define CMD_SUSPEND_HINT                0x65 /* in: u8 */
 118#define CMD_ENABLE_WAKE_TIMER           0x66 /* in: u8 */
 119#define CMD_SET_WAKE_TIMER              0x67 /* in: 32 */
 120#define CMD_ENABLE_WAKE_AUTORESET       0x68 /* in: u8 */
 121#define CMD_OLS_SET_LIMITS              0x69 /* in: u16, u16 */
 122#define CMD_OLS_GET_LIMITS              0x6a /* out: u16, u16 */
 123#define CMD_OLS_SET_CEILING             0x6b /* in: u16 */
 124#define CMD_OLS_GET_CEILING             0x6c /* out: u16 */
 125
 126/*
 127 * Accepted EC commands, and how many bytes they return. There are plenty
 128 * of EC commands that are no longer implemented, or are implemented only on
 129 * certain older boards.
 130 */
 131static const struct ec_cmd_t olpc_xo175_ec_cmds[] = {
 132        { CMD_GET_API_VERSION, 1 },
 133        { CMD_READ_VOLTAGE, 2 },
 134        { CMD_READ_CURRENT, 2 },
 135        { CMD_READ_ACR, 2 },
 136        { CMD_READ_BATT_TEMPERATURE, 2 },
 137        { CMD_READ_BATTERY_STATUS, 1 },
 138        { CMD_READ_SOC, 1 },
 139        { CMD_READ_GAUGE_ID, 8 },
 140        { CMD_READ_GAUGE_DATA, 1 },
 141        { CMD_READ_BOARD_ID, 2 },
 142        { CMD_READ_BATT_ERR_CODE, 1 },
 143        { CMD_SET_DCON_POWER, 0 },
 144        { CMD_RESET_EC, 0 },
 145        { CMD_READ_BATTERY_TYPE, 1 },
 146        { CMD_ENABLE_RUNIN_DISCHARGE, 0 },
 147        { CMD_DISABLE_RUNIN_DISCHARGE, 0 },
 148        { CMD_READ_MPPT_ACTIVE, 1 },
 149        { CMD_READ_MPPT_LIMIT, 1 },
 150        { CMD_SET_MPPT_LIMIT, 0 },
 151        { CMD_DISABLE_MPPT, 0 },
 152        { CMD_ENABLE_MPPT, 0 },
 153        { CMD_READ_VIN, 2 },
 154        { CMD_GET_FW_VERSION, 16 },
 155        { CMD_POWER_CYCLE, 0 },
 156        { CMD_POWER_OFF, 0 },
 157        { CMD_RESET_EC_SOFT, 0 },
 158        { CMD_ECHO, 5 },
 159        { CMD_GET_FW_DATE, 16 },
 160        { CMD_GET_FW_USER, 16 },
 161        { CMD_TURN_OFF_POWER, 0 },
 162        { CMD_READ_OLS, 2 },
 163        { CMD_OLS_SMT_LEDON, 0 },
 164        { CMD_OLS_SMT_LEDOFF, 0 },
 165        { CMD_START_OLS_ASSY, 0 },
 166        { CMD_STOP_OLS_ASSY, 0 },
 167        { CMD_OLS_SMTTEST_STOP, 0 },
 168        { CMD_READ_VIN_SCALED, 2 },
 169        { CMD_READ_BAT_MIN_W, 2 },
 170        { CMD_READ_BAR_MAX_W, 2 },
 171        { CMD_RESET_BAT_MINMAX_W, 0 },
 172        { CMD_READ_LOCATION, 1 },
 173        { CMD_WRITE_LOCATION, 0 },
 174        { CMD_GET_FW_HASH, 16 },
 175        { CMD_SUSPEND_HINT, 0 },
 176        { CMD_ENABLE_WAKE_TIMER, 0 },
 177        { CMD_SET_WAKE_TIMER, 0 },
 178        { CMD_ENABLE_WAKE_AUTORESET, 0 },
 179        { CMD_OLS_SET_LIMITS, 0 },
 180        { CMD_OLS_GET_LIMITS, 4 },
 181        { CMD_OLS_SET_CEILING, 0 },
 182        { CMD_OLS_GET_CEILING, 2 },
 183        { CMD_READ_EXT_SCI_MASK, 2 },
 184        { CMD_WRITE_EXT_SCI_MASK, 0 },
 185
 186        { }
 187};
 188
 189#define EC_MAX_CMD_DATA_LEN     5
 190#define EC_MAX_RESP_LEN         16
 191
 192#define LOG_BUF_SIZE            128
 193
 194#define PM_WAKEUP_TIME          1000
 195
 196#define EC_ALL_EVENTS           GENMASK(15, 0)
 197
 198enum ec_state_t {
 199        CMD_STATE_IDLE = 0,
 200        CMD_STATE_WAITING_FOR_SWITCH,
 201        CMD_STATE_CMD_IN_TX_FIFO,
 202        CMD_STATE_CMD_SENT,
 203        CMD_STATE_RESP_RECEIVED,
 204        CMD_STATE_ERROR_RECEIVED,
 205};
 206
 207struct olpc_xo175_ec_cmd {
 208        u8 command;
 209        u8 nr_args;
 210        u8 data_len;
 211        u8 args[EC_MAX_CMD_DATA_LEN];
 212};
 213
 214struct olpc_xo175_ec_resp {
 215        u8 channel;
 216        u8 byte;
 217};
 218
 219struct olpc_xo175_ec {
 220        bool suspended;
 221
 222        /* SPI related stuff. */
 223        struct spi_device *spi;
 224        struct spi_transfer xfer;
 225        struct spi_message msg;
 226        union {
 227                struct olpc_xo175_ec_cmd cmd;
 228                struct olpc_xo175_ec_resp resp;
 229        } tx_buf, rx_buf;
 230
 231        /* GPIO for the CMD signals. */
 232        struct gpio_desc *gpio_cmd;
 233
 234        /* Command handling related state. */
 235        spinlock_t cmd_state_lock;
 236        int cmd_state;
 237        bool cmd_running;
 238        struct completion cmd_done;
 239        struct olpc_xo175_ec_cmd cmd;
 240        u8 resp_data[EC_MAX_RESP_LEN];
 241        int expected_resp_len;
 242        int resp_len;
 243
 244        /* Power button. */
 245        struct input_dev *pwrbtn;
 246
 247        /* Debug handling. */
 248        char logbuf[LOG_BUF_SIZE];
 249        int logbuf_len;
 250};
 251
 252static struct platform_device *olpc_ec;
 253
 254static int olpc_xo175_ec_resp_len(u8 cmd)
 255{
 256        const struct ec_cmd_t *p;
 257
 258        for (p = olpc_xo175_ec_cmds; p->cmd; p++) {
 259                if (p->cmd == cmd)
 260                        return p->bytes_returned;
 261        }
 262
 263        return -EINVAL;
 264}
 265
 266static void olpc_xo175_ec_flush_logbuf(struct olpc_xo175_ec *priv)
 267{
 268        dev_dbg(&priv->spi->dev, "got debug string [%*pE]\n",
 269                                priv->logbuf_len, priv->logbuf);
 270        priv->logbuf_len = 0;
 271}
 272
 273static void olpc_xo175_ec_complete(void *arg);
 274
 275static void olpc_xo175_ec_send_command(struct olpc_xo175_ec *priv, void *cmd,
 276                                                                size_t cmdlen)
 277{
 278        int ret;
 279
 280        memcpy(&priv->tx_buf, cmd, cmdlen);
 281        priv->xfer.len = cmdlen;
 282
 283        spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
 284
 285        priv->msg.complete = olpc_xo175_ec_complete;
 286        priv->msg.context = priv;
 287
 288        ret = spi_async(priv->spi, &priv->msg);
 289        if (ret)
 290                dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);
 291}
 292
 293static void olpc_xo175_ec_read_packet(struct olpc_xo175_ec *priv)
 294{
 295        u8 nonce[] = {0xA5, 0x5A};
 296
 297        olpc_xo175_ec_send_command(priv, nonce, sizeof(nonce));
 298}
 299
 300static void olpc_xo175_ec_complete(void *arg)
 301{
 302        struct olpc_xo175_ec *priv = arg;
 303        struct device *dev = &priv->spi->dev;
 304        struct power_supply *psy;
 305        unsigned long flags;
 306        u8 channel;
 307        u8 byte;
 308        int ret;
 309
 310        ret = priv->msg.status;
 311        if (ret) {
 312                dev_err(dev, "SPI transfer failed: %d\n", ret);
 313
 314                spin_lock_irqsave(&priv->cmd_state_lock, flags);
 315                if (priv->cmd_running) {
 316                        priv->resp_len = 0;
 317                        priv->cmd_state = CMD_STATE_ERROR_RECEIVED;
 318                        complete(&priv->cmd_done);
 319                }
 320                spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 321
 322                if (ret != -EINTR)
 323                        olpc_xo175_ec_read_packet(priv);
 324
 325                return;
 326        }
 327
 328        channel = priv->rx_buf.resp.channel;
 329        byte = priv->rx_buf.resp.byte;
 330
 331        switch (channel) {
 332        case CHAN_NONE:
 333                spin_lock_irqsave(&priv->cmd_state_lock, flags);
 334
 335                if (!priv->cmd_running) {
 336                        /* We can safely ignore these */
 337                        dev_err(dev, "spurious FIFO read packet\n");
 338                        spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 339                        return;
 340                }
 341
 342                priv->cmd_state = CMD_STATE_CMD_SENT;
 343                if (!priv->expected_resp_len)
 344                        complete(&priv->cmd_done);
 345                olpc_xo175_ec_read_packet(priv);
 346
 347                spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 348                return;
 349
 350        case CHAN_SWITCH:
 351                spin_lock_irqsave(&priv->cmd_state_lock, flags);
 352
 353                if (!priv->cmd_running) {
 354                        /* Just go with the flow */
 355                        dev_err(dev, "spurious SWITCH packet\n");
 356                        memset(&priv->cmd, 0, sizeof(priv->cmd));
 357                        priv->cmd.command = CMD_ECHO;
 358                }
 359
 360                priv->cmd_state = CMD_STATE_CMD_IN_TX_FIFO;
 361
 362                /* Throw command into TxFIFO */
 363                gpiod_set_value_cansleep(priv->gpio_cmd, 0);
 364                olpc_xo175_ec_send_command(priv, &priv->cmd, sizeof(priv->cmd));
 365
 366                spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 367                return;
 368
 369        case CHAN_CMD_RESP:
 370                spin_lock_irqsave(&priv->cmd_state_lock, flags);
 371
 372                if (!priv->cmd_running) {
 373                        dev_err(dev, "spurious response packet\n");
 374                } else if (priv->resp_len >= priv->expected_resp_len) {
 375                        dev_err(dev, "too many response packets\n");
 376                } else {
 377                        priv->resp_data[priv->resp_len++] = byte;
 378                        if (priv->resp_len == priv->expected_resp_len) {
 379                                priv->cmd_state = CMD_STATE_RESP_RECEIVED;
 380                                complete(&priv->cmd_done);
 381                        }
 382                }
 383
 384                spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 385                break;
 386
 387        case CHAN_CMD_ERROR:
 388                spin_lock_irqsave(&priv->cmd_state_lock, flags);
 389
 390                if (!priv->cmd_running) {
 391                        dev_err(dev, "spurious cmd error packet\n");
 392                } else {
 393                        priv->resp_data[0] = byte;
 394                        priv->resp_len = 1;
 395                        priv->cmd_state = CMD_STATE_ERROR_RECEIVED;
 396                        complete(&priv->cmd_done);
 397                }
 398                spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 399                break;
 400
 401        case CHAN_KEYBOARD:
 402                dev_warn(dev, "keyboard is not supported\n");
 403                break;
 404
 405        case CHAN_TOUCHPAD:
 406                dev_warn(dev, "touchpad is not supported\n");
 407                break;
 408
 409        case CHAN_EVENT:
 410                dev_dbg(dev, "got event %.2x\n", byte);
 411                switch (byte) {
 412                case EVENT_AC_CHANGE:
 413                        psy = power_supply_get_by_name("olpc_ac");
 414                        if (psy) {
 415                                power_supply_changed(psy);
 416                                power_supply_put(psy);
 417                        }
 418                        break;
 419                case EVENT_BATTERY_STATUS:
 420                case EVENT_BATTERY_CRITICAL:
 421                case EVENT_BATTERY_SOC_CHANGE:
 422                case EVENT_BATTERY_ERROR:
 423                        psy = power_supply_get_by_name("olpc_battery");
 424                        if (psy) {
 425                                power_supply_changed(psy);
 426                                power_supply_put(psy);
 427                        }
 428                        break;
 429                case EVENT_POWER_PRESSED:
 430                        input_report_key(priv->pwrbtn, KEY_POWER, 1);
 431                        input_sync(priv->pwrbtn);
 432                        input_report_key(priv->pwrbtn, KEY_POWER, 0);
 433                        input_sync(priv->pwrbtn);
 434                        fallthrough;
 435                case EVENT_POWER_PRESS_WAKE:
 436                case EVENT_TIMED_HOST_WAKE:
 437                        pm_wakeup_event(priv->pwrbtn->dev.parent,
 438                                                PM_WAKEUP_TIME);
 439                        break;
 440                default:
 441                        dev_dbg(dev, "ignored unknown event %.2x\n", byte);
 442                        break;
 443                }
 444                break;
 445
 446        case CHAN_DEBUG:
 447                if (byte == '\n') {
 448                        olpc_xo175_ec_flush_logbuf(priv);
 449                } else if (isprint(byte)) {
 450                        priv->logbuf[priv->logbuf_len++] = byte;
 451                        if (priv->logbuf_len == LOG_BUF_SIZE)
 452                                olpc_xo175_ec_flush_logbuf(priv);
 453                }
 454                break;
 455
 456        default:
 457                dev_warn(dev, "unknown channel: %d, %.2x\n", channel, byte);
 458                break;
 459        }
 460
 461        /* Most non-command packets get the TxFIFO refilled and an ACK. */
 462        olpc_xo175_ec_read_packet(priv);
 463}
 464
 465/*
 466 * This function is protected with a mutex. We can safely assume that
 467 * there will be only one instance of this function running at a time.
 468 * One of the ways in which we enforce this is by waiting until we get
 469 * all response bytes back from the EC, rather than just the number that
 470 * the caller requests (otherwise, we might start a new command while an
 471 * old command's response bytes are still incoming).
 472 */
 473static int olpc_xo175_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *resp,
 474                                        size_t resp_len, void *ec_cb_arg)
 475{
 476        struct olpc_xo175_ec *priv = ec_cb_arg;
 477        struct device *dev = &priv->spi->dev;
 478        unsigned long flags;
 479        size_t nr_bytes;
 480        int ret = 0;
 481
 482        dev_dbg(dev, "CMD %x, %zd bytes expected\n", cmd, resp_len);
 483
 484        if (inlen > 5) {
 485                dev_err(dev, "command len %zd too big!\n", resp_len);
 486                return -EOVERFLOW;
 487        }
 488
 489        /* Suspending in the middle of an EC command hoses things badly! */
 490        if (WARN_ON(priv->suspended))
 491                return -EBUSY;
 492
 493        /* Ensure a valid command and return bytes */
 494        ret = olpc_xo175_ec_resp_len(cmd);
 495        if (ret < 0) {
 496                dev_err_ratelimited(dev, "unknown command 0x%x\n", cmd);
 497
 498                /*
 499                 * Assume the best in our callers, and allow unknown commands
 500                 * through. I'm not the charitable type, but it was beaten
 501                 * into me. Just maintain a minimum standard of sanity.
 502                 */
 503                if (resp_len > sizeof(priv->resp_data)) {
 504                        dev_err(dev, "response too big: %zd!\n", resp_len);
 505                        return -EOVERFLOW;
 506                }
 507                nr_bytes = resp_len;
 508        } else {
 509                nr_bytes = (size_t)ret;
 510                ret = 0;
 511        }
 512        resp_len = min(resp_len, nr_bytes);
 513
 514        spin_lock_irqsave(&priv->cmd_state_lock, flags);
 515
 516        /* Initialize the state machine */
 517        init_completion(&priv->cmd_done);
 518        priv->cmd_running = true;
 519        priv->cmd_state = CMD_STATE_WAITING_FOR_SWITCH;
 520        memset(&priv->cmd, 0, sizeof(priv->cmd));
 521        priv->cmd.command = cmd;
 522        priv->cmd.nr_args = inlen;
 523        priv->cmd.data_len = 0;
 524        memcpy(priv->cmd.args, inbuf, inlen);
 525        priv->expected_resp_len = nr_bytes;
 526        priv->resp_len = 0;
 527
 528        /* Tickle the cmd gpio to get things started */
 529        gpiod_set_value_cansleep(priv->gpio_cmd, 1);
 530
 531        spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 532
 533        /* The irq handler should do the rest */
 534        if (!wait_for_completion_timeout(&priv->cmd_done,
 535                        msecs_to_jiffies(4000))) {
 536                dev_err(dev, "EC cmd error: timeout in STATE %d\n",
 537                                priv->cmd_state);
 538                gpiod_set_value_cansleep(priv->gpio_cmd, 0);
 539                spi_slave_abort(priv->spi);
 540                olpc_xo175_ec_read_packet(priv);
 541                return -ETIMEDOUT;
 542        }
 543
 544        spin_lock_irqsave(&priv->cmd_state_lock, flags);
 545
 546        /* Deal with the results. */
 547        if (priv->cmd_state == CMD_STATE_ERROR_RECEIVED) {
 548                /* EC-provided error is in the single response byte */
 549                dev_err(dev, "command 0x%x returned error 0x%x\n",
 550                                                cmd, priv->resp_data[0]);
 551                ret = -EREMOTEIO;
 552        } else if (priv->resp_len != nr_bytes) {
 553                dev_err(dev, "command 0x%x returned %d bytes, expected %zd bytes\n",
 554                                                cmd, priv->resp_len, nr_bytes);
 555                ret = -EREMOTEIO;
 556        } else {
 557                /*
 558                 * We may have 8 bytes in priv->resp, but we only care about
 559                 * what we've been asked for. If the caller asked for only 2
 560                 * bytes, give them that. We've guaranteed that
 561                 * resp_len <= priv->resp_len and priv->resp_len == nr_bytes.
 562                 */
 563                memcpy(resp, priv->resp_data, resp_len);
 564        }
 565
 566        /* This should already be low, but just in case. */
 567        gpiod_set_value_cansleep(priv->gpio_cmd, 0);
 568        priv->cmd_running = false;
 569
 570        spin_unlock_irqrestore(&priv->cmd_state_lock, flags);
 571
 572        return ret;
 573}
 574
 575static int olpc_xo175_ec_set_event_mask(unsigned int mask)
 576{
 577        u8 args[2];
 578
 579        args[0] = mask >> 0;
 580        args[1] = mask >> 8;
 581        return olpc_ec_cmd(CMD_WRITE_EXT_SCI_MASK, args, 2, NULL, 0);
 582}
 583
 584static void olpc_xo175_ec_power_off(void)
 585{
 586        while (1) {
 587                olpc_ec_cmd(CMD_POWER_OFF, NULL, 0, NULL, 0);
 588                mdelay(1000);
 589        }
 590}
 591
 592static int __maybe_unused olpc_xo175_ec_suspend(struct device *dev)
 593{
 594        struct olpc_xo175_ec *priv = dev_get_drvdata(dev);
 595        static struct {
 596                u8 suspend;
 597                u32 suspend_count;
 598        } __packed hintargs;
 599        static unsigned int suspend_count;
 600
 601        /*
 602         * SOC_SLEEP is not wired to the EC on B3 and earlier boards.
 603         * This command lets the EC know instead. The suspend count doesn't seem
 604         * to be used anywhere but in the EC debug output.
 605         */
 606        hintargs.suspend = 1;
 607        hintargs.suspend_count = suspend_count++;
 608        olpc_ec_cmd(CMD_SUSPEND_HINT, (void *)&hintargs, sizeof(hintargs),
 609                                                                NULL, 0);
 610
 611        /*
 612         * After we've sent the suspend hint, don't allow further EC commands
 613         * to be run until we've resumed. Userspace tasks should be frozen,
 614         * but kernel threads and interrupts could still schedule EC commands.
 615         */
 616        priv->suspended = true;
 617
 618        return 0;
 619}
 620
 621static int __maybe_unused olpc_xo175_ec_resume_noirq(struct device *dev)
 622{
 623        struct olpc_xo175_ec *priv = dev_get_drvdata(dev);
 624
 625        priv->suspended = false;
 626
 627        return 0;
 628}
 629
 630static int __maybe_unused olpc_xo175_ec_resume(struct device *dev)
 631{
 632        u8 x = 0;
 633
 634        /*
 635         * The resume hint is only needed if no other commands are
 636         * being sent during resume. all it does is tell the EC
 637         * the SoC is definitely awake.
 638         */
 639        olpc_ec_cmd(CMD_SUSPEND_HINT, &x, 1, NULL, 0);
 640
 641        /* Enable all EC events while we're awake */
 642        olpc_xo175_ec_set_event_mask(EC_ALL_EVENTS);
 643
 644        return 0;
 645}
 646
 647static struct olpc_ec_driver olpc_xo175_ec_driver = {
 648        .ec_cmd = olpc_xo175_ec_cmd,
 649};
 650
 651static int olpc_xo175_ec_remove(struct spi_device *spi)
 652{
 653        if (pm_power_off == olpc_xo175_ec_power_off)
 654                pm_power_off = NULL;
 655
 656        spi_slave_abort(spi);
 657
 658        platform_device_unregister(olpc_ec);
 659        olpc_ec = NULL;
 660
 661        return 0;
 662}
 663
 664static int olpc_xo175_ec_probe(struct spi_device *spi)
 665{
 666        struct olpc_xo175_ec *priv;
 667        int ret;
 668
 669        if (olpc_ec) {
 670                dev_err(&spi->dev, "OLPC EC already registered.\n");
 671                return -EBUSY;
 672        }
 673
 674        priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
 675        if (!priv)
 676                return -ENOMEM;
 677
 678        priv->gpio_cmd = devm_gpiod_get(&spi->dev, "cmd", GPIOD_OUT_LOW);
 679        if (IS_ERR(priv->gpio_cmd)) {
 680                dev_err(&spi->dev, "failed to get cmd gpio: %ld\n",
 681                                        PTR_ERR(priv->gpio_cmd));
 682                return PTR_ERR(priv->gpio_cmd);
 683        }
 684
 685        priv->spi = spi;
 686
 687        spin_lock_init(&priv->cmd_state_lock);
 688        priv->cmd_state = CMD_STATE_IDLE;
 689        init_completion(&priv->cmd_done);
 690
 691        priv->logbuf_len = 0;
 692
 693        /* Set up power button input device */
 694        priv->pwrbtn = devm_input_allocate_device(&spi->dev);
 695        if (!priv->pwrbtn)
 696                return -ENOMEM;
 697        priv->pwrbtn->name = "Power Button";
 698        priv->pwrbtn->dev.parent = &spi->dev;
 699        input_set_capability(priv->pwrbtn, EV_KEY, KEY_POWER);
 700        ret = input_register_device(priv->pwrbtn);
 701        if (ret) {
 702                dev_err(&spi->dev, "error registering input device: %d\n", ret);
 703                return ret;
 704        }
 705
 706        spi_set_drvdata(spi, priv);
 707
 708        priv->xfer.rx_buf = &priv->rx_buf;
 709        priv->xfer.tx_buf = &priv->tx_buf;
 710
 711        olpc_xo175_ec_read_packet(priv);
 712
 713        olpc_ec_driver_register(&olpc_xo175_ec_driver, priv);
 714        olpc_ec = platform_device_register_resndata(&spi->dev, "olpc-ec", -1,
 715                                                        NULL, 0, NULL, 0);
 716
 717        /* Enable all EC events while we're awake */
 718        olpc_xo175_ec_set_event_mask(EC_ALL_EVENTS);
 719
 720        if (pm_power_off == NULL)
 721                pm_power_off = olpc_xo175_ec_power_off;
 722
 723        dev_info(&spi->dev, "OLPC XO-1.75 Embedded Controller driver\n");
 724
 725        return 0;
 726}
 727
 728static const struct dev_pm_ops olpc_xo175_ec_pm_ops = {
 729        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, olpc_xo175_ec_resume_noirq)
 730        SET_RUNTIME_PM_OPS(olpc_xo175_ec_suspend, olpc_xo175_ec_resume, NULL)
 731};
 732
 733static const struct of_device_id olpc_xo175_ec_of_match[] = {
 734        { .compatible = "olpc,xo1.75-ec" },
 735        { }
 736};
 737MODULE_DEVICE_TABLE(of, olpc_xo175_ec_of_match);
 738
 739static const struct spi_device_id olpc_xo175_ec_id_table[] = {
 740        { "xo1.75-ec", 0 },
 741        {}
 742};
 743MODULE_DEVICE_TABLE(spi, olpc_xo175_ec_id_table);
 744
 745static struct spi_driver olpc_xo175_ec_spi_driver = {
 746        .driver = {
 747                .name   = "olpc-xo175-ec",
 748                .of_match_table = olpc_xo175_ec_of_match,
 749                .pm = &olpc_xo175_ec_pm_ops,
 750        },
 751        .probe          = olpc_xo175_ec_probe,
 752        .remove         = olpc_xo175_ec_remove,
 753};
 754module_spi_driver(olpc_xo175_ec_spi_driver);
 755
 756MODULE_DESCRIPTION("OLPC XO-1.75 Embedded Controller driver");
 757MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>"); /* Functionality */
 758MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); /* Bugs */
 759MODULE_LICENSE("GPL");
 760