linux/drivers/acpi/sbshc.c
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   1/*
   2 * SMBus driver for ACPI Embedded Controller (v0.1)
   3 *
   4 * Copyright (c) 2007 Alexey Starikovskiy
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation version 2.
   9 */
  10
  11#include <acpi/acpi_bus.h>
  12#include <acpi/acpi_drivers.h>
  13#include <linux/wait.h>
  14#include <linux/slab.h>
  15#include <linux/delay.h>
  16#include <linux/module.h>
  17#include <linux/interrupt.h>
  18#include "sbshc.h"
  19
  20#define PREFIX "ACPI: "
  21
  22#define ACPI_SMB_HC_CLASS       "smbus_host_ctl"
  23#define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
  24
  25struct acpi_smb_hc {
  26        struct acpi_ec *ec;
  27        struct mutex lock;
  28        wait_queue_head_t wait;
  29        u8 offset;
  30        u8 query_bit;
  31        smbus_alarm_callback callback;
  32        void *context;
  33};
  34
  35static int acpi_smbus_hc_add(struct acpi_device *device);
  36static int acpi_smbus_hc_remove(struct acpi_device *device, int type);
  37
  38static const struct acpi_device_id sbs_device_ids[] = {
  39        {"ACPI0001", 0},
  40        {"ACPI0005", 0},
  41        {"", 0},
  42};
  43
  44MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
  45
  46static struct acpi_driver acpi_smb_hc_driver = {
  47        .name = "smbus_hc",
  48        .class = ACPI_SMB_HC_CLASS,
  49        .ids = sbs_device_ids,
  50        .ops = {
  51                .add = acpi_smbus_hc_add,
  52                .remove = acpi_smbus_hc_remove,
  53                },
  54};
  55
  56union acpi_smb_status {
  57        u8 raw;
  58        struct {
  59                u8 status:5;
  60                u8 reserved:1;
  61                u8 alarm:1;
  62                u8 done:1;
  63        } fields;
  64};
  65
  66enum acpi_smb_status_codes {
  67        SMBUS_OK = 0,
  68        SMBUS_UNKNOWN_FAILURE = 0x07,
  69        SMBUS_DEVICE_ADDRESS_NACK = 0x10,
  70        SMBUS_DEVICE_ERROR = 0x11,
  71        SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
  72        SMBUS_UNKNOWN_ERROR = 0x13,
  73        SMBUS_DEVICE_ACCESS_DENIED = 0x17,
  74        SMBUS_TIMEOUT = 0x18,
  75        SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
  76        SMBUS_BUSY = 0x1a,
  77        SMBUS_PEC_ERROR = 0x1f,
  78};
  79
  80enum acpi_smb_offset {
  81        ACPI_SMB_PROTOCOL = 0,  /* protocol, PEC */
  82        ACPI_SMB_STATUS = 1,    /* status */
  83        ACPI_SMB_ADDRESS = 2,   /* address */
  84        ACPI_SMB_COMMAND = 3,   /* command */
  85        ACPI_SMB_DATA = 4,      /* 32 data registers */
  86        ACPI_SMB_BLOCK_COUNT = 0x24,    /* number of data bytes */
  87        ACPI_SMB_ALARM_ADDRESS = 0x25,  /* alarm address */
  88        ACPI_SMB_ALARM_DATA = 0x26,     /* 2 bytes alarm data */
  89};
  90
  91static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
  92{
  93        return ec_read(hc->offset + address, data);
  94}
  95
  96static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
  97{
  98        return ec_write(hc->offset + address, data);
  99}
 100
 101static inline int smb_check_done(struct acpi_smb_hc *hc)
 102{
 103        union acpi_smb_status status = {.raw = 0};
 104        smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
 105        return status.fields.done && (status.fields.status == SMBUS_OK);
 106}
 107
 108static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
 109{
 110        if (wait_event_timeout(hc->wait, smb_check_done(hc),
 111                               msecs_to_jiffies(timeout)))
 112                return 0;
 113        /*
 114         * After the timeout happens, OS will try to check the status of SMbus.
 115         * If the status is what OS expected, it will be regarded as the bogus
 116         * timeout.
 117         */
 118        if (smb_check_done(hc))
 119                return 0;
 120        else
 121                return -ETIME;
 122}
 123
 124static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
 125                                  u8 address, u8 command, u8 *data, u8 length)
 126{
 127        int ret = -EFAULT, i;
 128        u8 temp, sz = 0;
 129
 130        if (!hc) {
 131                printk(KERN_ERR PREFIX "host controller is not configured\n");
 132                return ret;
 133        }
 134
 135        mutex_lock(&hc->lock);
 136        if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
 137                goto end;
 138        if (temp) {
 139                ret = -EBUSY;
 140                goto end;
 141        }
 142        smb_hc_write(hc, ACPI_SMB_COMMAND, command);
 143        if (!(protocol & 0x01)) {
 144                smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
 145                for (i = 0; i < length; ++i)
 146                        smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
 147        }
 148        smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
 149        smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
 150        /*
 151         * Wait for completion. Save the status code, data size,
 152         * and data into the return package (if required by the protocol).
 153         */
 154        ret = wait_transaction_complete(hc, 1000);
 155        if (ret || !(protocol & 0x01))
 156                goto end;
 157        switch (protocol) {
 158        case SMBUS_RECEIVE_BYTE:
 159        case SMBUS_READ_BYTE:
 160                sz = 1;
 161                break;
 162        case SMBUS_READ_WORD:
 163                sz = 2;
 164                break;
 165        case SMBUS_READ_BLOCK:
 166                if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
 167                        ret = -EFAULT;
 168                        goto end;
 169                }
 170                sz &= 0x1f;
 171                break;
 172        }
 173        for (i = 0; i < sz; ++i)
 174                smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
 175      end:
 176        mutex_unlock(&hc->lock);
 177        return ret;
 178}
 179
 180int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 181                    u8 command, u8 *data)
 182{
 183        return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
 184}
 185
 186EXPORT_SYMBOL_GPL(acpi_smbus_read);
 187
 188int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 189                     u8 command, u8 *data, u8 length)
 190{
 191        return acpi_smbus_transaction(hc, protocol, address, command, data, length);
 192}
 193
 194EXPORT_SYMBOL_GPL(acpi_smbus_write);
 195
 196int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
 197                                 smbus_alarm_callback callback, void *context)
 198{
 199        mutex_lock(&hc->lock);
 200        hc->callback = callback;
 201        hc->context = context;
 202        mutex_unlock(&hc->lock);
 203        return 0;
 204}
 205
 206EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
 207
 208int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
 209{
 210        mutex_lock(&hc->lock);
 211        hc->callback = NULL;
 212        hc->context = NULL;
 213        mutex_unlock(&hc->lock);
 214        return 0;
 215}
 216
 217EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
 218
 219static inline void acpi_smbus_callback(void *context)
 220{
 221        struct acpi_smb_hc *hc = context;
 222        if (hc->callback)
 223                hc->callback(hc->context);
 224}
 225
 226static int smbus_alarm(void *context)
 227{
 228        struct acpi_smb_hc *hc = context;
 229        union acpi_smb_status status;
 230        u8 address;
 231        if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
 232                return 0;
 233        /* Check if it is only a completion notify */
 234        if (status.fields.done)
 235                wake_up(&hc->wait);
 236        if (!status.fields.alarm)
 237                return 0;
 238        mutex_lock(&hc->lock);
 239        smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
 240        status.fields.alarm = 0;
 241        smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
 242        /* We are only interested in events coming from known devices */
 243        switch (address >> 1) {
 244                case ACPI_SBS_CHARGER:
 245                case ACPI_SBS_MANAGER:
 246                case ACPI_SBS_BATTERY:
 247                        acpi_os_execute(OSL_NOTIFY_HANDLER,
 248                                        acpi_smbus_callback, hc);
 249                default:;
 250        }
 251        mutex_unlock(&hc->lock);
 252        return 0;
 253}
 254
 255typedef int (*acpi_ec_query_func) (void *data);
 256
 257extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 258                              acpi_handle handle, acpi_ec_query_func func,
 259                              void *data);
 260
 261static int acpi_smbus_hc_add(struct acpi_device *device)
 262{
 263        int status;
 264        unsigned long long val;
 265        struct acpi_smb_hc *hc;
 266
 267        if (!device)
 268                return -EINVAL;
 269
 270        status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
 271        if (ACPI_FAILURE(status)) {
 272                printk(KERN_ERR PREFIX "error obtaining _EC.\n");
 273                return -EIO;
 274        }
 275
 276        strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
 277        strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
 278
 279        hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
 280        if (!hc)
 281                return -ENOMEM;
 282        mutex_init(&hc->lock);
 283        init_waitqueue_head(&hc->wait);
 284
 285        hc->ec = acpi_driver_data(device->parent);
 286        hc->offset = (val >> 8) & 0xff;
 287        hc->query_bit = val & 0xff;
 288        device->driver_data = hc;
 289
 290        acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
 291        printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
 292                hc->ec, hc->offset, hc->query_bit);
 293
 294        return 0;
 295}
 296
 297extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
 298
 299static int acpi_smbus_hc_remove(struct acpi_device *device, int type)
 300{
 301        struct acpi_smb_hc *hc;
 302
 303        if (!device)
 304                return -EINVAL;
 305
 306        hc = acpi_driver_data(device);
 307        acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
 308        kfree(hc);
 309        device->driver_data = NULL;
 310        return 0;
 311}
 312
 313module_acpi_driver(acpi_smb_hc_driver);
 314
 315MODULE_LICENSE("GPL");
 316MODULE_AUTHOR("Alexey Starikovskiy");
 317MODULE_DESCRIPTION("ACPI SMBus HC driver");
 318
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