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"); 291