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 = be64_to_cpu(msg.params[1]); 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 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 /* For two messages, we basically support only simple 108 * smbus transactions of a write plus a read. We might 109 * want to allow also two writes but we'd have to bounce 110 * the data into a single buffer. 111 */ 112 if ((msgs[0].flags & I2C_M_RD) || !(msgs[1].flags & I2C_M_RD)) 113 return -EOPNOTSUPP; 114 if (msgs[0].len > 4) 115 return -EOPNOTSUPP; 116 if (msgs[0].addr != msgs[1].addr) 117 return -EOPNOTSUPP; 118 req.type = OPAL_I2C_SM_READ; 119 req.addr = cpu_to_be16(msgs[0].addr); 120 req.subaddr_sz = msgs[0].len; 121 for (i = 0; i < msgs[0].len; i++) 122 req.subaddr = (req.subaddr << 8) | msgs[0].buf[i]; 123 req.subaddr = cpu_to_be32(req.subaddr); 124 req.size = cpu_to_be32(msgs[1].len); 125 req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf)); 126 break; 127 default: 128 return -EOPNOTSUPP; 129 } 130 131 rc = i2c_opal_send_request(opal_id, &req); 132 if (rc) 133 return rc; 134 135 return num; 136 } 137 138 static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr, 139 unsigned short flags, char read_write, 140 u8 command, int size, union i2c_smbus_data *data) 141 { 142 unsigned long opal_id = (unsigned long)adap->algo_data; 143 struct opal_i2c_request req; 144 u8 local[2]; 145 int rc; 146 147 memset(&req, 0, sizeof(req)); 148 149 req.addr = cpu_to_be16(addr); 150 switch (size) { 151 case I2C_SMBUS_BYTE: 152 req.buffer_ra = cpu_to_be64(__pa(&data->byte)); 153 req.size = cpu_to_be32(1); 154 /* Fall through */ 155 case I2C_SMBUS_QUICK: 156 req.type = (read_write == I2C_SMBUS_READ) ? 157 OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE; 158 break; 159 case I2C_SMBUS_BYTE_DATA: 160 req.buffer_ra = cpu_to_be64(__pa(&data->byte)); 161 req.size = cpu_to_be32(1); 162 req.subaddr = cpu_to_be32(command); 163 req.subaddr_sz = 1; 164 req.type = (read_write == I2C_SMBUS_READ) ? 165 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 166 break; 167 case I2C_SMBUS_WORD_DATA: 168 if (!read_write) { 169 local[0] = data->word & 0xff; 170 local[1] = (data->word >> 8) & 0xff; 171 } 172 req.buffer_ra = cpu_to_be64(__pa(local)); 173 req.size = cpu_to_be32(2); 174 req.subaddr = cpu_to_be32(command); 175 req.subaddr_sz = 1; 176 req.type = (read_write == I2C_SMBUS_READ) ? 177 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 178 break; 179 case I2C_SMBUS_I2C_BLOCK_DATA: 180 req.buffer_ra = cpu_to_be64(__pa(&data->block[1])); 181 req.size = cpu_to_be32(data->block[0]); 182 req.subaddr = cpu_to_be32(command); 183 req.subaddr_sz = 1; 184 req.type = (read_write == I2C_SMBUS_READ) ? 185 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 186 break; 187 default: 188 return -EINVAL; 189 } 190 191 rc = i2c_opal_send_request(opal_id, &req); 192 if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) { 193 data->word = ((u16)local[1]) << 8; 194 data->word |= local[0]; 195 } 196 197 return rc; 198 } 199 200 static u32 i2c_opal_func(struct i2c_adapter *adapter) 201 { 202 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 203 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 204 I2C_FUNC_SMBUS_I2C_BLOCK; 205 } 206 207 static const struct i2c_algorithm i2c_opal_algo = { 208 .master_xfer = i2c_opal_master_xfer, 209 .smbus_xfer = i2c_opal_smbus_xfer, 210 .functionality = i2c_opal_func, 211 }; 212 213 static int i2c_opal_probe(struct platform_device *pdev) 214 { 215 struct i2c_adapter *adapter; 216 const char *pname; 217 u32 opal_id; 218 int rc; 219 220 if (!pdev->dev.of_node) 221 return -ENODEV; 222 223 rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id); 224 if (rc) { 225 dev_err(&pdev->dev, "Missing ibm,opal-id property !\n"); 226 return -EIO; 227 } 228 229 adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL); 230 if (!adapter) 231 return -ENOMEM; 232 233 adapter->algo = &i2c_opal_algo; 234 adapter->algo_data = (void *)(unsigned long)opal_id; 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 } 250 251 static 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 } 259 260 static const struct of_device_id i2c_opal_of_match[] = { 261 { 262 .compatible = "ibm,opal-i2c", 263 }, 264 { } 265 }; 266 MODULE_DEVICE_TABLE(of, i2c_opal_of_match); 267 268 static 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 }; 276 277 static 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 } 284 module_init(i2c_opal_init); 285 286 static void __exit i2c_opal_exit(void) 287 { 288 return platform_driver_unregister(&i2c_opal_driver); 289 } 290 module_exit(i2c_opal_exit); 291 292 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>"); 293 MODULE_DESCRIPTION("IBM OPAL I2C driver"); 294 MODULE_LICENSE("GPL"); 295