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 = be64_to_cpu(msg.params[1]); 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