sbshc.c

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