LXR linux/drivers/acpi/sbshc.c

   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 <linux/acpi.h>
  12#include <linux/wait.h>
  13#include <linux/slab.h>
  14#include <linux/delay.h>
  15#include <linux/module.h>
  16#include <linux/interrupt.h>
  17#include "sbshc.h"
  18
  19#define PREFIX "ACPI: "
  20
  21#define ACPI_SMB_HC_CLASS       "smbus_host_ctl"
  22#define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
  23
  24struct acpi_smb_hc {
  25        struct acpi_ec *ec;
  26        struct mutex lock;
  27        wait_queue_head_t wait;
  28        u8 offset;
  29        u8 query_bit;
  30        smbus_alarm_callback callback;
  31        void *context;
  32        bool done;
  33};
  34
  35static int acpi_smbus_hc_add(struct acpi_device *device);
  36static int acpi_smbus_hc_remove(struct acpi_device *device);
  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 int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
 102{
 103        if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
 104                return 0;
 105        return -ETIME;
 106}
 107
 108static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
 109                                  u8 address, u8 command, u8 *data, u8 length)
 110{
 111        int ret = -EFAULT, i;
 112        u8 temp, sz = 0;
 113
 114        if (!hc) {
 115                printk(KERN_ERR PREFIX "host controller is not configured\n");
 116                return ret;
 117        }
 118
 119        mutex_lock(&hc->lock);
 120        hc->done = false;
 121        if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
 122                goto end;
 123        if (temp) {
 124                ret = -EBUSY;
 125                goto end;
 126        }
 127        smb_hc_write(hc, ACPI_SMB_COMMAND, command);
 128        if (!(protocol & 0x01)) {
 129                smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
 130                for (i = 0; i < length; ++i)
 131                        smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
 132        }
 133        smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
 134        smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
 135        /*
 136         * Wait for completion. Save the status code, data size,
 137         * and data into the return package (if required by the protocol).
 138         */
 139        ret = wait_transaction_complete(hc, 1000);
 140        if (ret || !(protocol & 0x01))
 141                goto end;
 142        switch (protocol) {
 143        case SMBUS_RECEIVE_BYTE:
 144        case SMBUS_READ_BYTE:
 145                sz = 1;
 146                break;
 147        case SMBUS_READ_WORD:
 148                sz = 2;
 149                break;
 150        case SMBUS_READ_BLOCK:
 151                if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
 152                        ret = -EFAULT;
 153                        goto end;
 154                }
 155                sz &= 0x1f;
 156                break;
 157        }
 158        for (i = 0; i < sz; ++i)
 159                smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
 160      end:
 161        mutex_unlock(&hc->lock);
 162        return ret;
 163}
 164
 165int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 166                    u8 command, u8 *data)
 167{
 168        return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
 169}
 170
 171EXPORT_SYMBOL_GPL(acpi_smbus_read);
 172
 173int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 174                     u8 command, u8 *data, u8 length)
 175{
 176        return acpi_smbus_transaction(hc, protocol, address, command, data, length);
 177}
 178
 179EXPORT_SYMBOL_GPL(acpi_smbus_write);
 180
 181int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
 182                                 smbus_alarm_callback callback, void *context)
 183{
 184        mutex_lock(&hc->lock);
 185        hc->callback = callback;
 186        hc->context = context;
 187        mutex_unlock(&hc->lock);
 188        return 0;
 189}
 190
 191EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
 192
 193int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
 194{
 195        mutex_lock(&hc->lock);
 196        hc->callback = NULL;
 197        hc->context = NULL;
 198        mutex_unlock(&hc->lock);
 199        return 0;
 200}
 201
 202EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
 203
 204static inline void acpi_smbus_callback(void *context)
 205{
 206        struct acpi_smb_hc *hc = context;
 207        if (hc->callback)
 208                hc->callback(hc->context);
 209}
 210
 211static int smbus_alarm(void *context)
 212{
 213        struct acpi_smb_hc *hc = context;
 214        union acpi_smb_status status;
 215        u8 address;
 216        if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
 217                return 0;
 218        /* Check if it is only a completion notify */
 219        if (status.fields.done && status.fields.status == SMBUS_OK) {
 220                hc->done = true;
 221                wake_up(&hc->wait);
 222        }
 223        if (!status.fields.alarm)
 224                return 0;
 225        mutex_lock(&hc->lock);
 226        smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
 227        status.fields.alarm = 0;
 228        smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
 229        /* We are only interested in events coming from known devices */
 230        switch (address >> 1) {
 231                case ACPI_SBS_CHARGER:
 232                case ACPI_SBS_MANAGER:
 233                case ACPI_SBS_BATTERY:
 234                        acpi_os_execute(OSL_NOTIFY_HANDLER,
 235                                        acpi_smbus_callback, hc);
 236                default:;
 237        }
 238        mutex_unlock(&hc->lock);
 239        return 0;
 240}
 241
 242typedef int (*acpi_ec_query_func) (void *data);
 243
 244extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 245                              acpi_handle handle, acpi_ec_query_func func,
 246                              void *data);
 247
 248static int acpi_smbus_hc_add(struct acpi_device *device)
 249{
 250        int status;
 251        unsigned long long val;
 252        struct acpi_smb_hc *hc;
 253
 254        if (!device)
 255                return -EINVAL;
 256
 257        status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
 258        if (ACPI_FAILURE(status)) {
 259                printk(KERN_ERR PREFIX "error obtaining _EC.\n");
 260                return -EIO;
 261        }
 262
 263        strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
 264        strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
 265
 266        hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
 267        if (!hc)
 268                return -ENOMEM;
 269        mutex_init(&hc->lock);
 270        init_waitqueue_head(&hc->wait);
 271
 272        hc->ec = acpi_driver_data(device->parent);
 273        hc->offset = (val >> 8) & 0xff;
 274        hc->query_bit = val & 0xff;
 275        device->driver_data = hc;
 276
 277        acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
 278        printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
 279                hc->ec, hc->offset, hc->query_bit);
 280
 281        return 0;
 282}
 283
 284extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
 285
 286static int acpi_smbus_hc_remove(struct acpi_device *device)
 287{
 288        struct acpi_smb_hc *hc;
 289
 290        if (!device)
 291                return -EINVAL;
 292
 293        hc = acpi_driver_data(device);
 294        acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
 295        kfree(hc);
 296        device->driver_data = NULL;
 297        return 0;
 298}
 299
 300module_acpi_driver(acpi_smb_hc_driver);
 301
 302MODULE_LICENSE("GPL");
 303MODULE_AUTHOR("Alexey Starikovskiy");
 304MODULE_DESCRIPTION("ACPI SMBus HC driver");
 305