drivers/acpi/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
  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
  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
  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
  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
 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
 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
 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
 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
 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
 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
 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
 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
 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");