GNU Linux-libre 5.10.219-gnu1
[releases.git] / drivers / platform / olpc / olpc-xo175-ec.c
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
27 struct ec_cmd_t {
28         u8 cmd;
29         u8 bytes_returned;
30 };
31
32 enum 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  */
131 static 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
198 enum 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
207 struct 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
214 struct olpc_xo175_ec_resp {
215         u8 channel;
216         u8 byte;
217 };
218
219 struct 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
252 static struct platform_device *olpc_ec;
253
254 static 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
266 static 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
273 static void olpc_xo175_ec_complete(void *arg);
274
275 static 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
293 static 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
300 static 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  */
473 static 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
575 static 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
584 static 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
592 static 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
621 static 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
630 static 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
647 static struct olpc_ec_driver olpc_xo175_ec_driver = {
648         .ec_cmd = olpc_xo175_ec_cmd,
649 };
650
651 static 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
664 static 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
728 static 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
733 static const struct of_device_id olpc_xo175_ec_of_match[] = {
734         { .compatible = "olpc,xo1.75-ec" },
735         { }
736 };
737 MODULE_DEVICE_TABLE(of, olpc_xo175_ec_of_match);
738
739 static const struct spi_device_id olpc_xo175_ec_id_table[] = {
740         { "xo1.75-ec", 0 },
741         {}
742 };
743 MODULE_DEVICE_TABLE(spi, olpc_xo175_ec_id_table);
744
745 static 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 };
754 module_spi_driver(olpc_xo175_ec_spi_driver);
755
756 MODULE_DESCRIPTION("OLPC XO-1.75 Embedded Controller driver");
757 MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>"); /* Functionality */
758 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); /* Bugs */
759 MODULE_LICENSE("GPL");