1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Supports for the power IC on the Surface 3 tablet.
4 *
5 * (C) Copyright 2016-2018 Red Hat, Inc
6 * (C) Copyright 2016-2018 Benjamin Tissoires <benjamin.tissoires@gmail.com>
7 * (C) Copyright 2016 Stephen Just <stephenjust@gmail.com>
8 *
9 * This driver has been reverse-engineered by parsing the DSDT of the Surface 3
10 * and looking at the registers of the chips.
11 *
12 * The DSDT allowed to find out that:
13 * - the driver is required for the ACPI BAT0 device to communicate to the chip
14 * through an operation region.
15 * - the various defines for the operation region functions to communicate with
16 * this driver
17 * - the DSM 3f99e367-6220-4955-8b0f-06ef2ae79412 allows to trigger ACPI
18 * events to BAT0 (the code is all available in the DSDT).
19 *
20 * Further findings regarding the 2 chips declared in the MSHW0011 are:
21 * - there are 2 chips declared:
22 * . 0x22 seems to control the ADP1 line status (and probably the charger)
23 * . 0x55 controls the battery directly
24 * - the battery chip uses a SMBus protocol (using plain SMBus allows non
25 * destructive commands):
26 * . the commands/registers used are in the range 0x00..0x7F
27 * . if bit 8 (0x80) is set in the SMBus command, the returned value is the
28 * same as when it is not set. There is a high chance this bit is the
29 * read/write
30 * . the various registers semantic as been deduced by observing the register
31 * dumps.
32 */
33
34 #include <linux/acpi.h>
35 #include <linux/bits.h>
36 #include <linux/freezer.h>
37 #include <linux/i2c.h>
38 #include <linux/kernel.h>
39 #include <linux/kthread.h>
40 #include <linux/slab.h>
41 #include <linux/types.h>
42 #include <linux/uuid.h>
43 #include <asm/unaligned.h>
44
45 #define SURFACE_3_POLL_INTERVAL (2 * HZ)
46 #define SURFACE_3_STRLEN 10
47
48 struct mshw0011_data {
49 struct i2c_client *adp1;
50 struct i2c_client *bat0;
51 unsigned short notify_mask;
52 struct task_struct *poll_task;
53 bool kthread_running;
54
55 bool charging;
56 bool bat_charging;
57 u8 trip_point;
58 s32 full_capacity;
59 };
60
61 struct mshw0011_handler_data {
62 struct acpi_connection_info info;
63 struct i2c_client *client;
64 };
65
66 struct bix {
67 u32 revision;
68 u32 power_unit;
69 u32 design_capacity;
70 u32 last_full_charg_capacity;
71 u32 battery_technology;
72 u32 design_voltage;
73 u32 design_capacity_of_warning;
74 u32 design_capacity_of_low;
75 u32 cycle_count;
76 u32 measurement_accuracy;
77 u32 max_sampling_time;
78 u32 min_sampling_time;
79 u32 max_average_interval;
80 u32 min_average_interval;
81 u32 battery_capacity_granularity_1;
82 u32 battery_capacity_granularity_2;
83 char model[SURFACE_3_STRLEN];
84 char serial[SURFACE_3_STRLEN];
85 char type[SURFACE_3_STRLEN];
86 char OEM[SURFACE_3_STRLEN];
87 } __packed;
88
89 struct bst {
90 u32 battery_state;
91 s32 battery_present_rate;
92 u32 battery_remaining_capacity;
93 u32 battery_present_voltage;
94 } __packed;
95
96 struct gsb_command {
97 u8 arg0;
98 u8 arg1;
99 u8 arg2;
100 } __packed;
101
102 struct gsb_buffer {
103 u8 status;
104 u8 len;
105 u8 ret;
106 union {
107 struct gsb_command cmd;
108 struct bst bst;
109 struct bix bix;
110 } __packed;
111 } __packed;
112
113 #define ACPI_BATTERY_STATE_DISCHARGING BIT(0)
114 #define ACPI_BATTERY_STATE_CHARGING BIT(1)
115 #define ACPI_BATTERY_STATE_CRITICAL BIT(2)
116
117 #define MSHW0011_CMD_DEST_BAT0 0x01
118 #define MSHW0011_CMD_DEST_ADP1 0x03
119
120 #define MSHW0011_CMD_BAT0_STA 0x01
121 #define MSHW0011_CMD_BAT0_BIX 0x02
122 #define MSHW0011_CMD_BAT0_BCT 0x03
123 #define MSHW0011_CMD_BAT0_BTM 0x04
124 #define MSHW0011_CMD_BAT0_BST 0x05
125 #define MSHW0011_CMD_BAT0_BTP 0x06
126 #define MSHW0011_CMD_ADP1_PSR 0x07
127 #define MSHW0011_CMD_BAT0_PSOC 0x09
128 #define MSHW0011_CMD_BAT0_PMAX 0x0a
129 #define MSHW0011_CMD_BAT0_PSRC 0x0b
130 #define MSHW0011_CMD_BAT0_CHGI 0x0c
131 #define MSHW0011_CMD_BAT0_ARTG 0x0d
132
133 #define MSHW0011_NOTIFY_GET_VERSION 0x00
134 #define MSHW0011_NOTIFY_ADP1 0x01
135 #define MSHW0011_NOTIFY_BAT0_BST 0x02
136 #define MSHW0011_NOTIFY_BAT0_BIX 0x05
137
138 #define MSHW0011_ADP1_REG_PSR 0x04
139
140 #define MSHW0011_BAT0_REG_CAPACITY 0x0c
141 #define MSHW0011_BAT0_REG_FULL_CHG_CAPACITY 0x0e
142 #define MSHW0011_BAT0_REG_DESIGN_CAPACITY 0x40
143 #define MSHW0011_BAT0_REG_VOLTAGE 0x08
144 #define MSHW0011_BAT0_REG_RATE 0x14
145 #define MSHW0011_BAT0_REG_OEM 0x45
146 #define MSHW0011_BAT0_REG_TYPE 0x4e
147 #define MSHW0011_BAT0_REG_SERIAL_NO 0x56
148 #define MSHW0011_BAT0_REG_CYCLE_CNT 0x6e
149
150 #define MSHW0011_EV_2_5_MASK GENMASK(8, 0)
151
152 /* 3f99e367-6220-4955-8b0f-06ef2ae79412 */
153 static const guid_t mshw0011_guid =
154 GUID_INIT(0x3F99E367, 0x6220, 0x4955, 0x8B, 0x0F, 0x06, 0xEF,
155 0x2A, 0xE7, 0x94, 0x12);
156
157 static int
mshw0011_notify(struct mshw0011_data * cdata,u8 arg1,u8 arg2,unsigned int * ret_value)158 mshw0011_notify(struct mshw0011_data *cdata, u8 arg1, u8 arg2,
159 unsigned int *ret_value)
160 {
161 union acpi_object *obj;
162 acpi_handle handle;
163 unsigned int i;
164
165 handle = ACPI_HANDLE(&cdata->adp1->dev);
166 if (!handle)
167 return -ENODEV;
168
169 obj = acpi_evaluate_dsm_typed(handle, &mshw0011_guid, arg1, arg2, NULL,
170 ACPI_TYPE_BUFFER);
171 if (!obj) {
172 dev_err(&cdata->adp1->dev, "device _DSM execution failed\n");
173 return -ENODEV;
174 }
175
176 *ret_value = 0;
177 for (i = 0; i < obj->buffer.length; i++)
178 *ret_value |= obj->buffer.pointer[i] << (i * 8);
179
180 ACPI_FREE(obj);
181 return 0;
182 }
183
184 static const struct bix default_bix = {
185 .revision = 0x00,
186 .power_unit = 0x01,
187 .design_capacity = 0x1dca,
188 .last_full_charg_capacity = 0x1dca,
189 .battery_technology = 0x01,
190 .design_voltage = 0x10df,
191 .design_capacity_of_warning = 0x8f,
192 .design_capacity_of_low = 0x47,
193 .cycle_count = 0xffffffff,
194 .measurement_accuracy = 0x00015f90,
195 .max_sampling_time = 0x03e8,
196 .min_sampling_time = 0x03e8,
197 .max_average_interval = 0x03e8,
198 .min_average_interval = 0x03e8,
199 .battery_capacity_granularity_1 = 0x45,
200 .battery_capacity_granularity_2 = 0x11,
201 .model = "P11G8M",
202 .serial = "",
203 .type = "LION",
204 .OEM = "",
205 };
206
mshw0011_bix(struct mshw0011_data * cdata,struct bix * bix)207 static int mshw0011_bix(struct mshw0011_data *cdata, struct bix *bix)
208 {
209 struct i2c_client *client = cdata->bat0;
210 char buf[SURFACE_3_STRLEN];
211 int ret;
212
213 *bix = default_bix;
214
215 /* get design capacity */
216 ret = i2c_smbus_read_word_data(client,
217 MSHW0011_BAT0_REG_DESIGN_CAPACITY);
218 if (ret < 0) {
219 dev_err(&client->dev, "Error reading design capacity: %d\n",
220 ret);
221 return ret;
222 }
223 bix->design_capacity = ret;
224
225 /* get last full charge capacity */
226 ret = i2c_smbus_read_word_data(client,
227 MSHW0011_BAT0_REG_FULL_CHG_CAPACITY);
228 if (ret < 0) {
229 dev_err(&client->dev,
230 "Error reading last full charge capacity: %d\n", ret);
231 return ret;
232 }
233 bix->last_full_charg_capacity = ret;
234
235 /* get serial number */
236 ret = i2c_smbus_read_i2c_block_data(client, MSHW0011_BAT0_REG_SERIAL_NO,
237 sizeof(buf), buf);
238 if (ret != sizeof(buf)) {
239 dev_err(&client->dev, "Error reading serial no: %d\n", ret);
240 return ret;
241 }
242 snprintf(bix->serial, ARRAY_SIZE(bix->serial), "%3pE%6pE", buf + 7, buf);
243
244 /* get cycle count */
245 ret = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_CYCLE_CNT);
246 if (ret < 0) {
247 dev_err(&client->dev, "Error reading cycle count: %d\n", ret);
248 return ret;
249 }
250 bix->cycle_count = ret;
251
252 /* get OEM name */
253 ret = i2c_smbus_read_i2c_block_data(client, MSHW0011_BAT0_REG_OEM,
254 4, buf);
255 if (ret != 4) {
256 dev_err(&client->dev, "Error reading cycle count: %d\n", ret);
257 return ret;
258 }
259 snprintf(bix->OEM, ARRAY_SIZE(bix->OEM), "%3pE", buf);
260
261 return 0;
262 }
263
mshw0011_bst(struct mshw0011_data * cdata,struct bst * bst)264 static int mshw0011_bst(struct mshw0011_data *cdata, struct bst *bst)
265 {
266 struct i2c_client *client = cdata->bat0;
267 int rate, capacity, voltage, state;
268 s16 tmp;
269
270 rate = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_RATE);
271 if (rate < 0)
272 return rate;
273
274 capacity = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_CAPACITY);
275 if (capacity < 0)
276 return capacity;
277
278 voltage = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_VOLTAGE);
279 if (voltage < 0)
280 return voltage;
281
282 tmp = rate;
283 bst->battery_present_rate = abs((s32)tmp);
284
285 state = 0;
286 if ((s32) tmp > 0)
287 state |= ACPI_BATTERY_STATE_CHARGING;
288 else if ((s32) tmp < 0)
289 state |= ACPI_BATTERY_STATE_DISCHARGING;
290 bst->battery_state = state;
291
292 bst->battery_remaining_capacity = capacity;
293 bst->battery_present_voltage = voltage;
294
295 return 0;
296 }
297
mshw0011_adp_psr(struct mshw0011_data * cdata)298 static int mshw0011_adp_psr(struct mshw0011_data *cdata)
299 {
300 return i2c_smbus_read_byte_data(cdata->adp1, MSHW0011_ADP1_REG_PSR);
301 }
302
mshw0011_isr(struct mshw0011_data * cdata)303 static int mshw0011_isr(struct mshw0011_data *cdata)
304 {
305 struct bst bst;
306 struct bix bix;
307 int ret;
308 bool status, bat_status;
309
310 ret = mshw0011_adp_psr(cdata);
311 if (ret < 0)
312 return ret;
313
314 status = ret;
315 if (status != cdata->charging)
316 mshw0011_notify(cdata, cdata->notify_mask,
317 MSHW0011_NOTIFY_ADP1, &ret);
318
319 cdata->charging = status;
320
321 ret = mshw0011_bst(cdata, &bst);
322 if (ret < 0)
323 return ret;
324
325 bat_status = bst.battery_state;
326 if (bat_status != cdata->bat_charging)
327 mshw0011_notify(cdata, cdata->notify_mask,
328 MSHW0011_NOTIFY_BAT0_BST, &ret);
329
330 cdata->bat_charging = bat_status;
331
332 ret = mshw0011_bix(cdata, &bix);
333 if (ret < 0)
334 return ret;
335
336 if (bix.last_full_charg_capacity != cdata->full_capacity)
337 mshw0011_notify(cdata, cdata->notify_mask,
338 MSHW0011_NOTIFY_BAT0_BIX, &ret);
339
340 cdata->full_capacity = bix.last_full_charg_capacity;
341
342 return 0;
343 }
344
mshw0011_poll_task(void * data)345 static int mshw0011_poll_task(void *data)
346 {
347 struct mshw0011_data *cdata = data;
348 int ret = 0;
349
350 cdata->kthread_running = true;
351
352 set_freezable();
353
354 while (!kthread_should_stop()) {
355 schedule_timeout_interruptible(SURFACE_3_POLL_INTERVAL);
356 try_to_freeze();
357 ret = mshw0011_isr(data);
358 if (ret)
359 break;
360 }
361
362 cdata->kthread_running = false;
363 return ret;
364 }
365
366 static acpi_status
mshw0011_space_handler(u32 function,acpi_physical_address command,u32 bits,u64 * value64,void * handler_context,void * region_context)367 mshw0011_space_handler(u32 function, acpi_physical_address command,
368 u32 bits, u64 *value64,
369 void *handler_context, void *region_context)
370 {
371 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
372 struct mshw0011_handler_data *data = handler_context;
373 struct acpi_connection_info *info = &data->info;
374 struct acpi_resource_i2c_serialbus *sb;
375 struct i2c_client *client = data->client;
376 struct mshw0011_data *cdata = i2c_get_clientdata(client);
377 struct acpi_resource *ares;
378 u32 accessor_type = function >> 16;
379 acpi_status ret;
380 int status = 1;
381
382 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
383 if (ACPI_FAILURE(ret))
384 return ret;
385
386 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
387 ret = AE_BAD_PARAMETER;
388 goto err;
389 }
390
391 if (accessor_type != ACPI_GSB_ACCESS_ATTRIB_RAW_PROCESS) {
392 ret = AE_BAD_PARAMETER;
393 goto err;
394 }
395
396 if (gsb->cmd.arg0 == MSHW0011_CMD_DEST_ADP1 &&
397 gsb->cmd.arg1 == MSHW0011_CMD_ADP1_PSR) {
398 status = mshw0011_adp_psr(cdata);
399 if (status >= 0) {
400 ret = AE_OK;
401 goto out;
402 } else {
403 ret = AE_ERROR;
404 goto err;
405 }
406 }
407
408 if (gsb->cmd.arg0 != MSHW0011_CMD_DEST_BAT0) {
409 ret = AE_BAD_PARAMETER;
410 goto err;
411 }
412
413 switch (gsb->cmd.arg1) {
414 case MSHW0011_CMD_BAT0_STA:
415 break;
416 case MSHW0011_CMD_BAT0_BIX:
417 ret = mshw0011_bix(cdata, &gsb->bix);
418 break;
419 case MSHW0011_CMD_BAT0_BTP:
420 cdata->trip_point = gsb->cmd.arg2;
421 break;
422 case MSHW0011_CMD_BAT0_BST:
423 ret = mshw0011_bst(cdata, &gsb->bst);
424 break;
425 default:
426 dev_info(&cdata->bat0->dev, "command(0x%02x) is not supported.\n", gsb->cmd.arg1);
427 ret = AE_BAD_PARAMETER;
428 goto err;
429 }
430
431 out:
432 gsb->ret = status;
433 gsb->status = 0;
434
435 err:
436 ACPI_FREE(ares);
437 return ret;
438 }
439
mshw0011_install_space_handler(struct i2c_client * client)440 static int mshw0011_install_space_handler(struct i2c_client *client)
441 {
442 struct acpi_device *adev;
443 struct mshw0011_handler_data *data;
444 acpi_status status;
445
446 adev = ACPI_COMPANION(&client->dev);
447 if (!adev)
448 return -ENODEV;
449
450 data = kzalloc(sizeof(struct mshw0011_handler_data),
451 GFP_KERNEL);
452 if (!data)
453 return -ENOMEM;
454
455 data->client = client;
456 status = acpi_bus_attach_private_data(adev->handle, (void *)data);
457 if (ACPI_FAILURE(status)) {
458 kfree(data);
459 return -ENOMEM;
460 }
461
462 status = acpi_install_address_space_handler(adev->handle,
463 ACPI_ADR_SPACE_GSBUS,
464 &mshw0011_space_handler,
465 NULL,
466 data);
467 if (ACPI_FAILURE(status)) {
468 dev_err(&client->dev, "Error installing i2c space handler\n");
469 acpi_bus_detach_private_data(adev->handle);
470 kfree(data);
471 return -ENOMEM;
472 }
473
474 acpi_dev_clear_dependencies(adev);
475 return 0;
476 }
477
mshw0011_remove_space_handler(struct i2c_client * client)478 static void mshw0011_remove_space_handler(struct i2c_client *client)
479 {
480 struct mshw0011_handler_data *data;
481 acpi_handle handle;
482 acpi_status status;
483
484 handle = ACPI_HANDLE(&client->dev);
485 if (!handle)
486 return;
487
488 acpi_remove_address_space_handler(handle,
489 ACPI_ADR_SPACE_GSBUS,
490 &mshw0011_space_handler);
491
492 status = acpi_bus_get_private_data(handle, (void **)&data);
493 if (ACPI_SUCCESS(status))
494 kfree(data);
495
496 acpi_bus_detach_private_data(handle);
497 }
498
mshw0011_probe(struct i2c_client * client)499 static int mshw0011_probe(struct i2c_client *client)
500 {
501 struct i2c_board_info board_info;
502 struct device *dev = &client->dev;
503 struct i2c_client *bat0;
504 struct mshw0011_data *data;
505 int error, mask;
506
507 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
508 if (!data)
509 return -ENOMEM;
510
511 data->adp1 = client;
512 i2c_set_clientdata(client, data);
513
514 memset(&board_info, 0, sizeof(board_info));
515 strlcpy(board_info.type, "MSHW0011-bat0", I2C_NAME_SIZE);
516
517 bat0 = i2c_acpi_new_device(dev, 1, &board_info);
518 if (IS_ERR(bat0))
519 return PTR_ERR(bat0);
520
521 data->bat0 = bat0;
522 i2c_set_clientdata(bat0, data);
523
524 error = mshw0011_notify(data, 1, MSHW0011_NOTIFY_GET_VERSION, &mask);
525 if (error)
526 goto out_err;
527
528 data->notify_mask = mask == MSHW0011_EV_2_5_MASK;
529
530 data->poll_task = kthread_run(mshw0011_poll_task, data, "mshw0011_adp");
531 if (IS_ERR(data->poll_task)) {
532 error = PTR_ERR(data->poll_task);
533 dev_err(&client->dev, "Unable to run kthread err %d\n", error);
534 goto out_err;
535 }
536
537 error = mshw0011_install_space_handler(client);
538 if (error)
539 goto out_err;
540
541 return 0;
542
543 out_err:
544 if (data->kthread_running)
545 kthread_stop(data->poll_task);
546 i2c_unregister_device(data->bat0);
547 return error;
548 }
549
mshw0011_remove(struct i2c_client * client)550 static int mshw0011_remove(struct i2c_client *client)
551 {
552 struct mshw0011_data *cdata = i2c_get_clientdata(client);
553
554 mshw0011_remove_space_handler(client);
555
556 if (cdata->kthread_running)
557 kthread_stop(cdata->poll_task);
558
559 i2c_unregister_device(cdata->bat0);
560
561 return 0;
562 }
563
564 static const struct acpi_device_id mshw0011_acpi_match[] = {
565 { "MSHW0011", 0 },
566 { }
567 };
568 MODULE_DEVICE_TABLE(acpi, mshw0011_acpi_match);
569
570 static struct i2c_driver mshw0011_driver = {
571 .probe_new = mshw0011_probe,
572 .remove = mshw0011_remove,
573 .driver = {
574 .name = "mshw0011",
575 .acpi_match_table = mshw0011_acpi_match,
576 },
577 };
578 module_i2c_driver(mshw0011_driver);
579
580 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
581 MODULE_DESCRIPTION("mshw0011 driver");
582 MODULE_LICENSE("GPL v2");
583