drivers/i2c/busses/i2c-opal.c

   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
  31 static 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
  51 static 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
  80 exit:
  81         opal_async_release_token(token);
  82         return rc;
  83 }
  84
  85 static 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 1:
  98                 req.type = (msgs[0].flags & I2C_M_RD) ?
  99                         OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
 100                 req.addr = cpu_to_be16(msgs[0].addr);
 101                 req.size = cpu_to_be32(msgs[0].len);
 102                 req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf));
 103                 break;
 104         case 2:
 105                 req.type = (msgs[1].flags & I2C_M_RD) ?
 106                         OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 107                 req.addr = cpu_to_be16(msgs[0].addr);
 108                 req.subaddr_sz = msgs[0].len;
 109                 for (i = 0; i < msgs[0].len; i++)
 110                         req.subaddr = (req.subaddr << 8) | msgs[0].buf[i];
 111                 req.subaddr = cpu_to_be32(req.subaddr);
 112                 req.size = cpu_to_be32(msgs[1].len);
 113                 req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf));
 114                 break;
 115         }
 116
 117         rc = i2c_opal_send_request(opal_id, &req);
 118         if (rc)
 119                 return rc;
 120
 121         return num;
 122 }
 123
 124 static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr,
 125                                unsigned short flags, char read_write,
 126                                u8 command, int size, union i2c_smbus_data *data)
 127 {
 128         unsigned long opal_id = (unsigned long)adap->algo_data;
 129         struct opal_i2c_request req;
 130         u8 local[2];
 131         int rc;
 132
 133         memset(&req, 0, sizeof(req));
 134
 135         req.addr = cpu_to_be16(addr);
 136         switch (size) {
 137         case I2C_SMBUS_BYTE:
 138                 req.buffer_ra = cpu_to_be64(__pa(&data->byte));
 139                 req.size = cpu_to_be32(1);
 140                 /* Fall through */
 141         case I2C_SMBUS_QUICK:
 142                 req.type = (read_write == I2C_SMBUS_READ) ?
 143                         OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
 144                 break;
 145         case I2C_SMBUS_BYTE_DATA:
 146                 req.buffer_ra = cpu_to_be64(__pa(&data->byte));
 147                 req.size = cpu_to_be32(1);
 148                 req.subaddr = cpu_to_be32(command);
 149                 req.subaddr_sz = 1;
 150                 req.type = (read_write == I2C_SMBUS_READ) ?
 151                         OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 152                 break;
 153         case I2C_SMBUS_WORD_DATA:
 154                 if (!read_write) {
 155                         local[0] = data->word & 0xff;
 156                         local[1] = (data->word >> 8) & 0xff;
 157                 }
 158                 req.buffer_ra = cpu_to_be64(__pa(local));
 159                 req.size = cpu_to_be32(2);
 160                 req.subaddr = cpu_to_be32(command);
 161                 req.subaddr_sz = 1;
 162                 req.type = (read_write == I2C_SMBUS_READ) ?
 163                         OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 164                 break;
 165         case I2C_SMBUS_I2C_BLOCK_DATA:
 166                 req.buffer_ra = cpu_to_be64(__pa(&data->block[1]));
 167                 req.size = cpu_to_be32(data->block[0]);
 168                 req.subaddr = cpu_to_be32(command);
 169                 req.subaddr_sz = 1;
 170                 req.type = (read_write == I2C_SMBUS_READ) ?
 171                         OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
 172                 break;
 173         default:
 174                 return -EINVAL;
 175         }
 176
 177         rc = i2c_opal_send_request(opal_id, &req);
 178         if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) {
 179                 data->word = ((u16)local[1]) << 8;
 180                 data->word |= local[0];
 181         }
 182
 183         return rc;
 184 }
 185
 186 static u32 i2c_opal_func(struct i2c_adapter *adapter)
 187 {
 188         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 189                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 190                I2C_FUNC_SMBUS_I2C_BLOCK;
 191 }
 192
 193 static const struct i2c_algorithm i2c_opal_algo = {
 194         .master_xfer    = i2c_opal_master_xfer,
 195         .smbus_xfer     = i2c_opal_smbus_xfer,
 196         .functionality  = i2c_opal_func,
 197 };
 198
 199 /*
 200  * For two messages, we basically support simple smbus transactions of a
 201  * write-then-anything.
 202  */
 203 static const struct i2c_adapter_quirks i2c_opal_quirks = {
 204         .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
 205         .max_comb_1st_msg_len = 4,
 206 };
 207
 208 static int i2c_opal_probe(struct platform_device *pdev)
 209 {
 210         struct i2c_adapter      *adapter;
 211         const char              *pname;
 212         u32                     opal_id;
 213         int                     rc;
 214
 215         if (!pdev->dev.of_node)
 216                 return -ENODEV;
 217
 218         rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id);
 219         if (rc) {
 220                 dev_err(&pdev->dev, "Missing ibm,opal-id property !\n");
 221                 return -EIO;
 222         }
 223
 224         adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
 225         if (!adapter)
 226                 return -ENOMEM;
 227
 228         adapter->algo = &i2c_opal_algo;
 229         adapter->algo_data = (void *)(unsigned long)opal_id;
 230         adapter->quirks = &i2c_opal_quirks;
 231         adapter->dev.parent = &pdev->dev;
 232         adapter->dev.of_node = of_node_get(pdev->dev.of_node);
 233         pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL);
 234         if (pname)
 235                 strlcpy(adapter->name, pname, sizeof(adapter->name));
 236         else
 237                 strlcpy(adapter->name, "opal", sizeof(adapter->name));
 238
 239         platform_set_drvdata(pdev, adapter);
 240         rc = i2c_add_adapter(adapter);
 241         if (rc)
 242                 dev_err(&pdev->dev, "Failed to register the i2c adapter\n");
 243
 244         return rc;
 245 }
 246
 247 static int i2c_opal_remove(struct platform_device *pdev)
 248 {
 249         struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 250
 251         i2c_del_adapter(adapter);
 252
 253         return 0;
 254 }
 255
 256 static const struct of_device_id i2c_opal_of_match[] = {
 257         {
 258                 .compatible = "ibm,opal-i2c",
 259         },
 260         { }
 261 };
 262 MODULE_DEVICE_TABLE(of, i2c_opal_of_match);
 263
 264 static struct platform_driver i2c_opal_driver = {
 265         .probe  = i2c_opal_probe,
 266         .remove = i2c_opal_remove,
 267         .driver = {
 268                 .name           = "i2c-opal",
 269                 .of_match_table = i2c_opal_of_match,
 270         },
 271 };
 272
 273 static int __init i2c_opal_init(void)
 274 {
 275         if (!firmware_has_feature(FW_FEATURE_OPAL))
 276                 return -ENODEV;
 277
 278         return platform_driver_register(&i2c_opal_driver);
 279 }
 280 module_init(i2c_opal_init);
 281
 282 static void __exit i2c_opal_exit(void)
 283 {
 284         return platform_driver_unregister(&i2c_opal_driver);
 285 }
 286 module_exit(i2c_opal_exit);
 287
 288 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 289 MODULE_DESCRIPTION("IBM OPAL I2C driver");
 290 MODULE_LICENSE("GPL");