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 #include "internal.h"
  18
  19 #define ACPI_SMB_HC_CLASS       "smbus_host_ctl"
  20 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
  21
  22 struct 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
  33 static int acpi_smbus_hc_add(struct acpi_device *device);
  34 static void acpi_smbus_hc_remove(struct acpi_device *device);
  35
  36 static const struct acpi_device_id sbs_device_ids[] = {
  37         {"ACPI0001", 0},
  38         {"ACPI0005", 0},
  39         {"", 0},
  40 };
  41
  42 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
  43
  44 static 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
  54 union 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
  64 enum 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
  78 enum 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
  89 static 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
  94 static 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
  99 static 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
 106 static 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
 163 int 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
 169 EXPORT_SYMBOL_GPL(acpi_smbus_read);
 170
 171 int 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
 177 EXPORT_SYMBOL_GPL(acpi_smbus_write);
 178
 179 int 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
 189 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
 190
 191 int 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
 201 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
 202
 203 static 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
 210 static 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
 240 static 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
 276 static 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
 290 module_acpi_driver(acpi_smb_hc_driver);
 291
 292 MODULE_LICENSE("GPL");
 293 MODULE_AUTHOR("Alexey Starikovskiy");
 294 MODULE_DESCRIPTION("ACPI SMBus HC driver");