1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SMBus driver for ACPI Embedded Controller (v0.1)
4 *
5 * Copyright (c) 2007 Alexey Starikovskiy
6 */
7
8#define pr_fmt(fmt) "ACPI: " fmt
9
10#include <linux/acpi.h>
11#include <linux/wait.h>
12#include <linux/slab.h>
13#include <linux/delay.h>
14#include <linux/module.h>
15#include <linux/interrupt.h>
16#include "sbshc.h"
17
18#define ACPI_SMB_HC_CLASS	"smbus_host_ctl"
19#define ACPI_SMB_HC_DEVICE_NAME	"ACPI SMBus HC"
20
21struct acpi_smb_hc {
22	struct acpi_ec *ec;
23	struct mutex lock;
24	wait_queue_head_t wait;
25	u8 offset;
26	u8 query_bit;
27	smbus_alarm_callback callback;
28	void *context;
29	bool done;
30};
31
32static int acpi_smbus_hc_add(struct acpi_device *device);
33static void acpi_smbus_hc_remove(struct acpi_device *device);
34
35static const struct acpi_device_id sbs_device_ids[] = {
36	{"ACPI0001", 0},
37	{"ACPI0005", 0},
38	{"", 0},
39};
40
41MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
42
43static struct acpi_driver acpi_smb_hc_driver = {
44	.name = "smbus_hc",
45	.class = ACPI_SMB_HC_CLASS,
46	.ids = sbs_device_ids,
47	.ops = {
48		.add = acpi_smbus_hc_add,
49		.remove = acpi_smbus_hc_remove,
50		},
51};
52
53union acpi_smb_status {
54	u8 raw;
55	struct {
56		u8 status:5;
57		u8 reserved:1;
58		u8 alarm:1;
59		u8 done:1;
60	} fields;
61};
62
63enum acpi_smb_status_codes {
64	SMBUS_OK = 0,
65	SMBUS_UNKNOWN_FAILURE = 0x07,
66	SMBUS_DEVICE_ADDRESS_NACK = 0x10,
67	SMBUS_DEVICE_ERROR = 0x11,
68	SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
69	SMBUS_UNKNOWN_ERROR = 0x13,
70	SMBUS_DEVICE_ACCESS_DENIED = 0x17,
71	SMBUS_TIMEOUT = 0x18,
72	SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
73	SMBUS_BUSY = 0x1a,
74	SMBUS_PEC_ERROR = 0x1f,
75};
76
77enum acpi_smb_offset {
78	ACPI_SMB_PROTOCOL = 0,	/* protocol, PEC */
79	ACPI_SMB_STATUS = 1,	/* status */
80	ACPI_SMB_ADDRESS = 2,	/* address */
81	ACPI_SMB_COMMAND = 3,	/* command */
82	ACPI_SMB_DATA = 4,	/* 32 data registers */
83	ACPI_SMB_BLOCK_COUNT = 0x24,	/* number of data bytes */
84	ACPI_SMB_ALARM_ADDRESS = 0x25,	/* alarm address */
85	ACPI_SMB_ALARM_DATA = 0x26,	/* 2 bytes alarm data */
86};
87
88static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
89{
90	return ec_read(hc->offset + address, data);
91}
92
93static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
94{
95	return ec_write(hc->offset + address, data);
96}
97
98static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
99{
100	if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
101		return 0;
102	return -ETIME;
103}
104
105static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
106				  u8 address, u8 command, u8 *data, u8 length)
107{
108	int ret = -EFAULT, i;
109	u8 temp, sz = 0;
110
111	if (!hc) {
112		pr_err("host controller is not configured\n");
113		return ret;
114	}
115
116	mutex_lock(&hc->lock);
117	hc->done = false;
118	if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
119		goto end;
120	if (temp) {
121		ret = -EBUSY;
122		goto end;
123	}
124	smb_hc_write(hc, ACPI_SMB_COMMAND, command);
125	if (!(protocol & 0x01)) {
126		smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
127		for (i = 0; i < length; ++i)
128			smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
129	}
130	smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
131	smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
132	/*
133	 * Wait for completion. Save the status code, data size,
134	 * and data into the return package (if required by the protocol).
135	 */
136	ret = wait_transaction_complete(hc, 1000);
137	if (ret || !(protocol & 0x01))
138		goto end;
139	switch (protocol) {
140	case SMBUS_RECEIVE_BYTE:
141	case SMBUS_READ_BYTE:
142		sz = 1;
143		break;
144	case SMBUS_READ_WORD:
145		sz = 2;
146		break;
147	case SMBUS_READ_BLOCK:
148		if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
149			ret = -EFAULT;
150			goto end;
151		}
152		sz &= 0x1f;
153		break;
154	}
155	for (i = 0; i < sz; ++i)
156		smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
157      end:
158	mutex_unlock(&hc->lock);
159	return ret;
160}
161
162int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
163		    u8 command, u8 *data)
164{
165	return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
166}
167
168EXPORT_SYMBOL_GPL(acpi_smbus_read);
169
170int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
171		     u8 command, u8 *data, u8 length)
172{
173	return acpi_smbus_transaction(hc, protocol, address, command, data, length);
174}
175
176EXPORT_SYMBOL_GPL(acpi_smbus_write);
177
178int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
179				 smbus_alarm_callback callback, void *context)
180{
181	mutex_lock(&hc->lock);
182	hc->callback = callback;
183	hc->context = context;
184	mutex_unlock(&hc->lock);
185	return 0;
186}
187
188EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
189
190int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
191{
192	mutex_lock(&hc->lock);
193	hc->callback = NULL;
194	hc->context = NULL;
195	mutex_unlock(&hc->lock);
196	acpi_os_wait_events_complete();
197	return 0;
198}
199
200EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
201
202static inline void acpi_smbus_callback(void *context)
203{
204	struct acpi_smb_hc *hc = context;
205	if (hc->callback)
206		hc->callback(hc->context);
207}
208
209static int smbus_alarm(void *context)
210{
211	struct acpi_smb_hc *hc = context;
212	union acpi_smb_status status;
213	u8 address;
214	if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
215		return 0;
216	/* Check if it is only a completion notify */
217	if (status.fields.done && status.fields.status == SMBUS_OK) {
218		hc->done = true;
219		wake_up(&hc->wait);
220	}
221	if (!status.fields.alarm)
222		return 0;
223	mutex_lock(&hc->lock);
224	smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
225	status.fields.alarm = 0;
226	smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
227	/* We are only interested in events coming from known devices */
228	switch (address >> 1) {
229		case ACPI_SBS_CHARGER:
230		case ACPI_SBS_MANAGER:
231		case ACPI_SBS_BATTERY:
232			acpi_os_execute(OSL_NOTIFY_HANDLER,
233					acpi_smbus_callback, hc);
234	}
235	mutex_unlock(&hc->lock);
236	return 0;
237}
238
239typedef int (*acpi_ec_query_func) (void *data);
240
241extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
242			      acpi_handle handle, acpi_ec_query_func func,
243			      void *data);
244
245static int acpi_smbus_hc_add(struct acpi_device *device)
246{
247	int status;
248	unsigned long long val;
249	struct acpi_smb_hc *hc;
250
251	if (!device)
252		return -EINVAL;
253
254	status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
255	if (ACPI_FAILURE(status)) {
256		pr_err("error obtaining _EC.\n");
257		return -EIO;
258	}
259
260	strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
261	strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
262
263	hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
264	if (!hc)
265		return -ENOMEM;
266	mutex_init(&hc->lock);
267	init_waitqueue_head(&hc->wait);
268
269	hc->ec = acpi_driver_data(acpi_dev_parent(device));
270	hc->offset = (val >> 8) & 0xff;
271	hc->query_bit = val & 0xff;
272	device->driver_data = hc;
273
274	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
275	dev_info(&device->dev, "SBS HC: offset = 0x%0x, query_bit = 0x%0x\n",
276		 hc->offset, hc->query_bit);
277
278	return 0;
279}
280
281extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
282
283static void acpi_smbus_hc_remove(struct acpi_device *device)
284{
285	struct acpi_smb_hc *hc;
286
287	if (!device)
288		return;
289
290	hc = acpi_driver_data(device);
291	acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
292	acpi_os_wait_events_complete();
293	kfree(hc);
294	device->driver_data = NULL;
295}
296
297module_acpi_driver(acpi_smb_hc_driver);
298
299MODULE_LICENSE("GPL");
300MODULE_AUTHOR("Alexey Starikovskiy");
301MODULE_DESCRIPTION("ACPI SMBus HC driver");
302