linux/drivers/i2c/busses/i2c-opal.c
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   1/*
   2 * IBM OPAL I2C driver
   3 * Copyright (C) 2014 IBM
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program.
  17 */
  18
  19#include <linux/device.h>
  20#include <linux/i2c.h>
  21#include <linux/kernel.h>
  22#include <linux/mm.h>
  23#include <linux/module.h>
  24#include <linux/of.h>
  25#include <linux/platform_device.h>
  26#include <linux/slab.h>
  27
  28#include <asm/firmware.h>
  29#include <asm/opal.h>
  30
  31static int i2c_opal_translate_error(int rc)
  32{
  33        switch (rc) {
  34        case OPAL_NO_MEM:
  35                return -ENOMEM;
  36        case OPAL_PARAMETER:
  37                return -EINVAL;
  38        case OPAL_I2C_ARBT_LOST:
  39                return -EAGAIN;
  40        case OPAL_I2C_TIMEOUT:
  41                return -ETIMEDOUT;
  42        case OPAL_I2C_NACK_RCVD:
  43                return -ENXIO;
  44        case OPAL_I2C_STOP_ERR:
  45                return -EBUSY;
  46        default:
  47                return -EIO;
  48        }
  49}
  50
  51static int i2c_opal_send_request(u32 bus_id, struct opal_i2c_request *req)
  52{
  53        struct opal_msg msg;
  54        int token, rc;
  55
  56        token = opal_async_get_token_interruptible();
  57        if (token < 0) {
  58                if (token != -ERESTARTSYS)
  59                        pr_err("Failed to get the async token\n");
  60
  61                return token;
  62        }
  63
  64        rc = opal_i2c_request(token, bus_id, req);
  65        if (rc != OPAL_ASYNC_COMPLETION) {
  66                rc = i2c_opal_translate_error(rc);
  67                goto exit;
  68        }
  69
  70        rc = opal_async_wait_response(token, &msg);
  71        if (rc)
  72                goto exit;
  73
  74        rc = opal_get_async_rc(msg);
  75        if (rc != OPAL_SUCCESS) {
  76                rc = i2c_opal_translate_error(rc);
  77                goto exit;
  78        }
  79
  80exit:
  81        opal_async_release_token(token);
  82        return rc;
  83}
  84
  85static int i2c_opal_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  86                                int num)
  87{
  88        unsigned long opal_id = (unsigned long)adap->algo_data;
  89        struct opal_i2c_request req;
  90        int rc, i;
  91
  92        /* We only support fairly simple combinations here of one
  93         * or two messages
  94         */
  95        memset(&req, 0, sizeof(req));
  96        switch(num) {
  97        case 0:
  98                return 0;
  99        case 1:
 100                req.type = (msgs[0].flags & I2C_M_RD) ?
 101                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
 102                req.addr = cpu_to_be16(msgs[0].addr);
 103                req.size = cpu_to_be32(msgs[0].len);
 104                req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf));
 105                break;
 106        case 2:
 107                req.type = (msgs[1].flags & I2C_M_RD) ?
 108                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 109                req.addr = cpu_to_be16(msgs[0].addr);
 110                req.subaddr_sz = msgs[0].len;
 111                for (i = 0; i < msgs[0].len; i++)
 112                        req.subaddr = (req.subaddr << 8) | msgs[0].buf[i];
 113                req.subaddr = cpu_to_be32(req.subaddr);
 114                req.size = cpu_to_be32(msgs[1].len);
 115                req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf));
 116                break;
 117        default:
 118                return -EOPNOTSUPP;
 119        }
 120
 121        rc = i2c_opal_send_request(opal_id, &req);
 122        if (rc)
 123                return rc;
 124
 125        return num;
 126}
 127
 128static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr,
 129                               unsigned short flags, char read_write,
 130                               u8 command, int size, union i2c_smbus_data *data)
 131{
 132        unsigned long opal_id = (unsigned long)adap->algo_data;
 133        struct opal_i2c_request req;
 134        u8 local[2];
 135        int rc;
 136
 137        memset(&req, 0, sizeof(req));
 138
 139        req.addr = cpu_to_be16(addr);
 140        switch (size) {
 141        case I2C_SMBUS_BYTE:
 142                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
 143                req.size = cpu_to_be32(1);
 144                /* Fall through */
 145        case I2C_SMBUS_QUICK:
 146                req.type = (read_write == I2C_SMBUS_READ) ?
 147                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
 148                break;
 149        case I2C_SMBUS_BYTE_DATA:
 150                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
 151                req.size = cpu_to_be32(1);
 152                req.subaddr = cpu_to_be32(command);
 153                req.subaddr_sz = 1;
 154                req.type = (read_write == I2C_SMBUS_READ) ?
 155                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 156                break;
 157        case I2C_SMBUS_WORD_DATA:
 158                if (!read_write) {
 159                        local[0] = data->word & 0xff;
 160                        local[1] = (data->word >> 8) & 0xff;
 161                }
 162                req.buffer_ra = cpu_to_be64(__pa(local));
 163                req.size = cpu_to_be32(2);
 164                req.subaddr = cpu_to_be32(command);
 165                req.subaddr_sz = 1;
 166                req.type = (read_write == I2C_SMBUS_READ) ?
 167                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 168                break;
 169        case I2C_SMBUS_I2C_BLOCK_DATA:
 170                req.buffer_ra = cpu_to_be64(__pa(&data->block[1]));
 171                req.size = cpu_to_be32(data->block[0]);
 172                req.subaddr = cpu_to_be32(command);
 173                req.subaddr_sz = 1;
 174                req.type = (read_write == I2C_SMBUS_READ) ?
 175                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 176                break;
 177        default:
 178                return -EINVAL;
 179        }
 180
 181        rc = i2c_opal_send_request(opal_id, &req);
 182        if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) {
 183                data->word = ((u16)local[1]) << 8;
 184                data->word |= local[0];
 185        }
 186
 187        return rc;
 188}
 189
 190static u32 i2c_opal_func(struct i2c_adapter *adapter)
 191{
 192        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 193               I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 194               I2C_FUNC_SMBUS_I2C_BLOCK;
 195}
 196
 197static const struct i2c_algorithm i2c_opal_algo = {
 198        .master_xfer    = i2c_opal_master_xfer,
 199        .smbus_xfer     = i2c_opal_smbus_xfer,
 200        .functionality  = i2c_opal_func,
 201};
 202
 203/*
 204 * For two messages, we basically support simple smbus transactions of a
 205 * write-then-anything.
 206 */
 207static struct i2c_adapter_quirks i2c_opal_quirks = {
 208        .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
 209        .max_comb_1st_msg_len = 4,
 210};
 211
 212static int i2c_opal_probe(struct platform_device *pdev)
 213{
 214        struct i2c_adapter      *adapter;
 215        const char              *pname;
 216        u32                     opal_id;
 217        int                     rc;
 218
 219        if (!pdev->dev.of_node)
 220                return -ENODEV;
 221
 222        rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id);
 223        if (rc) {
 224                dev_err(&pdev->dev, "Missing ibm,opal-id property !\n");
 225                return -EIO;
 226        }
 227
 228        adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
 229        if (!adapter)
 230                return -ENOMEM;
 231
 232        adapter->algo = &i2c_opal_algo;
 233        adapter->algo_data = (void *)(unsigned long)opal_id;
 234        adapter->quirks = &i2c_opal_quirks;
 235        adapter->dev.parent = &pdev->dev;
 236        adapter->dev.of_node = of_node_get(pdev->dev.of_node);
 237        pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL);
 238        if (pname)
 239                strlcpy(adapter->name, pname, sizeof(adapter->name));
 240        else
 241                strlcpy(adapter->name, "opal", sizeof(adapter->name));
 242
 243        platform_set_drvdata(pdev, adapter);
 244        rc = i2c_add_adapter(adapter);
 245        if (rc)
 246                dev_err(&pdev->dev, "Failed to register the i2c adapter\n");
 247
 248        return rc;
 249}
 250
 251static int i2c_opal_remove(struct platform_device *pdev)
 252{
 253        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 254
 255        i2c_del_adapter(adapter);
 256
 257        return 0;
 258}
 259
 260static const struct of_device_id i2c_opal_of_match[] = {
 261        {
 262                .compatible = "ibm,opal-i2c",
 263        },
 264        { }
 265};
 266MODULE_DEVICE_TABLE(of, i2c_opal_of_match);
 267
 268static struct platform_driver i2c_opal_driver = {
 269        .probe  = i2c_opal_probe,
 270        .remove = i2c_opal_remove,
 271        .driver = {
 272                .name           = "i2c-opal",
 273                .of_match_table = i2c_opal_of_match,
 274        },
 275};
 276
 277static int __init i2c_opal_init(void)
 278{
 279        if (!firmware_has_feature(FW_FEATURE_OPAL))
 280                return -ENODEV;
 281
 282        return platform_driver_register(&i2c_opal_driver);
 283}
 284module_init(i2c_opal_init);
 285
 286static void __exit i2c_opal_exit(void)
 287{
 288        return platform_driver_unregister(&i2c_opal_driver);
 289}
 290module_exit(i2c_opal_exit);
 291
 292MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 293MODULE_DESCRIPTION("IBM OPAL I2C driver");
 294MODULE_LICENSE("GPL");
 295