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