xref: /openbmc/linux/drivers/acpi/sbshc.c (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
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  
21  struct 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  
32  static int acpi_smbus_hc_add(struct acpi_device *device);
33  static void acpi_smbus_hc_remove(struct acpi_device *device);
34  
35  static const struct acpi_device_id sbs_device_ids[] = {
36  	{"ACPI0001", 0},
37  	{"ACPI0005", 0},
38  	{"", 0},
39  };
40  
41  MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
42  
43  static 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  
53  union 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  
63  enum 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  
77  enum 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  
smb_hc_read(struct acpi_smb_hc * hc,u8 address,u8 * data)88  static 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  
smb_hc_write(struct acpi_smb_hc * hc,u8 address,u8 data)93  static 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  
wait_transaction_complete(struct acpi_smb_hc * hc,int timeout)98  static 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  
acpi_smbus_transaction(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)105  static 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  
acpi_smbus_read(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data)162  int 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  
168  EXPORT_SYMBOL_GPL(acpi_smbus_read);
169  
acpi_smbus_write(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)170  int 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  
176  EXPORT_SYMBOL_GPL(acpi_smbus_write);
177  
acpi_smbus_register_callback(struct acpi_smb_hc * hc,smbus_alarm_callback callback,void * context)178  int 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  
188  EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
189  
acpi_smbus_unregister_callback(struct acpi_smb_hc * hc)190  int 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  
200  EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
201  
acpi_smbus_callback(void * context)202  static 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  
smbus_alarm(void * context)209  static 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  
239  typedef int (*acpi_ec_query_func) (void *data);
240  
241  extern 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  
acpi_smbus_hc_add(struct acpi_device * device)245  static 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  
281  extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
282  
acpi_smbus_hc_remove(struct acpi_device * device)283  static 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  
297  module_acpi_driver(acpi_smb_hc_driver);
298  
299  MODULE_LICENSE("GPL");
300  MODULE_AUTHOR("Alexey Starikovskiy");
301  MODULE_DESCRIPTION("ACPI SMBus HC driver");
302