linux/drivers/acpi/sbshc.c
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   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
  21struct 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
  32static int acpi_smbus_hc_add(struct acpi_device *device);
  33static int acpi_smbus_hc_remove(struct acpi_device *device);
  34
  35static const struct acpi_device_id sbs_device_ids[] = {
  36        {"ACPI0001", 0},
  37        {"ACPI0005", 0},
  38        {"", 0},
  39};
  40
  41MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
  42
  43static 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
  53union 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
  63enum 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
  77enum 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
  88static 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
  93static 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
  98static 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
 105static 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
 162int 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
 168EXPORT_SYMBOL_GPL(acpi_smbus_read);
 169
 170int 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
 176EXPORT_SYMBOL_GPL(acpi_smbus_write);
 177
 178int 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
 188EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
 189
 190int 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
 200EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
 201
 202static 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
 209static 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
 239typedef int (*acpi_ec_query_func) (void *data);
 240
 241extern 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
 245static 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(device->parent);
 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
 281extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
 282
 283static int acpi_smbus_hc_remove(struct acpi_device *device)
 284{
 285        struct acpi_smb_hc *hc;
 286
 287        if (!device)
 288                return -EINVAL;
 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        return 0;
 296}
 297
 298module_acpi_driver(acpi_smb_hc_driver);
 299
 300MODULE_LICENSE("GPL");
 301MODULE_AUTHOR("Alexey Starikovskiy");
 302MODULE_DESCRIPTION("ACPI SMBus HC driver");
 303
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