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
olpc_xo175_ec_resp_len(u8 cmd)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
olpc_xo175_ec_flush_logbuf(struct olpc_xo175_ec * priv)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
olpc_xo175_ec_send_command(struct olpc_xo175_ec * priv,void * cmd,size_t cmdlen)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
olpc_xo175_ec_read_packet(struct olpc_xo175_ec * priv)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
olpc_xo175_ec_complete(void * arg)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 */
olpc_xo175_ec_cmd(u8 cmd,u8 * inbuf,size_t inlen,u8 * resp,size_t resp_len,void * ec_cb_arg)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_target_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
olpc_xo175_ec_set_event_mask(unsigned int mask)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
olpc_xo175_ec_power_off(void)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
olpc_xo175_ec_suspend(struct device * dev)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
olpc_xo175_ec_resume_noirq(struct device * dev)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
olpc_xo175_ec_resume(struct device * dev)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
olpc_xo175_ec_remove(struct spi_device * spi)651 static void 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_target_abort(spi);
657
658 platform_device_unregister(olpc_ec);
659 olpc_ec = NULL;
660 }
661
olpc_xo175_ec_probe(struct spi_device * spi)662 static int olpc_xo175_ec_probe(struct spi_device *spi)
663 {
664 struct olpc_xo175_ec *priv;
665 int ret;
666
667 if (olpc_ec) {
668 dev_err(&spi->dev, "OLPC EC already registered.\n");
669 return -EBUSY;
670 }
671
672 priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
673 if (!priv)
674 return -ENOMEM;
675
676 priv->gpio_cmd = devm_gpiod_get(&spi->dev, "cmd", GPIOD_OUT_LOW);
677 if (IS_ERR(priv->gpio_cmd)) {
678 dev_err(&spi->dev, "failed to get cmd gpio: %ld\n",
679 PTR_ERR(priv->gpio_cmd));
680 return PTR_ERR(priv->gpio_cmd);
681 }
682
683 priv->spi = spi;
684
685 spin_lock_init(&priv->cmd_state_lock);
686 priv->cmd_state = CMD_STATE_IDLE;
687 init_completion(&priv->cmd_done);
688
689 priv->logbuf_len = 0;
690
691 /* Set up power button input device */
692 priv->pwrbtn = devm_input_allocate_device(&spi->dev);
693 if (!priv->pwrbtn)
694 return -ENOMEM;
695 priv->pwrbtn->name = "Power Button";
696 priv->pwrbtn->dev.parent = &spi->dev;
697 input_set_capability(priv->pwrbtn, EV_KEY, KEY_POWER);
698 ret = input_register_device(priv->pwrbtn);
699 if (ret) {
700 dev_err(&spi->dev, "error registering input device: %d\n", ret);
701 return ret;
702 }
703
704 spi_set_drvdata(spi, priv);
705
706 priv->xfer.rx_buf = &priv->rx_buf;
707 priv->xfer.tx_buf = &priv->tx_buf;
708
709 olpc_xo175_ec_read_packet(priv);
710
711 olpc_ec_driver_register(&olpc_xo175_ec_driver, priv);
712 olpc_ec = platform_device_register_resndata(&spi->dev, "olpc-ec", -1,
713 NULL, 0, NULL, 0);
714
715 /* Enable all EC events while we're awake */
716 olpc_xo175_ec_set_event_mask(EC_ALL_EVENTS);
717
718 if (pm_power_off == NULL)
719 pm_power_off = olpc_xo175_ec_power_off;
720
721 dev_info(&spi->dev, "OLPC XO-1.75 Embedded Controller driver\n");
722
723 return 0;
724 }
725
726 static const struct dev_pm_ops olpc_xo175_ec_pm_ops = {
727 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, olpc_xo175_ec_resume_noirq)
728 SET_RUNTIME_PM_OPS(olpc_xo175_ec_suspend, olpc_xo175_ec_resume, NULL)
729 };
730
731 static const struct of_device_id olpc_xo175_ec_of_match[] = {
732 { .compatible = "olpc,xo1.75-ec" },
733 { }
734 };
735 MODULE_DEVICE_TABLE(of, olpc_xo175_ec_of_match);
736
737 static const struct spi_device_id olpc_xo175_ec_id_table[] = {
738 { "xo1.75-ec", 0 },
739 {}
740 };
741 MODULE_DEVICE_TABLE(spi, olpc_xo175_ec_id_table);
742
743 static struct spi_driver olpc_xo175_ec_spi_driver = {
744 .driver = {
745 .name = "olpc-xo175-ec",
746 .of_match_table = olpc_xo175_ec_of_match,
747 .pm = &olpc_xo175_ec_pm_ops,
748 },
749 .id_table = olpc_xo175_ec_id_table,
750 .probe = olpc_xo175_ec_probe,
751 .remove = olpc_xo175_ec_remove,
752 };
753 module_spi_driver(olpc_xo175_ec_spi_driver);
754
755 MODULE_DESCRIPTION("OLPC XO-1.75 Embedded Controller driver");
756 MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>"); /* Functionality */
757 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); /* Bugs */
758 MODULE_LICENSE("GPL");
759