1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IBM OPAL I2C driver 4 * Copyright (C) 2014 IBM 5 */ 6 7 #include <linux/device.h> 8 #include <linux/i2c.h> 9 #include <linux/kernel.h> 10 #include <linux/mm.h> 11 #include <linux/module.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 16 #include <asm/firmware.h> 17 #include <asm/opal.h> 18 19 static int i2c_opal_translate_error(int rc) 20 { 21 switch (rc) { 22 case OPAL_NO_MEM: 23 return -ENOMEM; 24 case OPAL_PARAMETER: 25 return -EINVAL; 26 case OPAL_I2C_ARBT_LOST: 27 return -EAGAIN; 28 case OPAL_I2C_TIMEOUT: 29 return -ETIMEDOUT; 30 case OPAL_I2C_NACK_RCVD: 31 return -ENXIO; 32 case OPAL_I2C_STOP_ERR: 33 return -EBUSY; 34 default: 35 return -EIO; 36 } 37 } 38 39 static int i2c_opal_send_request(u32 bus_id, struct opal_i2c_request *req) 40 { 41 struct opal_msg msg; 42 int token, rc; 43 44 token = opal_async_get_token_interruptible(); 45 if (token < 0) { 46 if (token != -ERESTARTSYS) 47 pr_err("Failed to get the async token\n"); 48 49 return token; 50 } 51 52 rc = opal_i2c_request(token, bus_id, req); 53 if (rc != OPAL_ASYNC_COMPLETION) { 54 rc = i2c_opal_translate_error(rc); 55 goto exit; 56 } 57 58 rc = opal_async_wait_response(token, &msg); 59 if (rc) 60 goto exit; 61 62 rc = opal_get_async_rc(msg); 63 if (rc != OPAL_SUCCESS) { 64 rc = i2c_opal_translate_error(rc); 65 goto exit; 66 } 67 68 exit: 69 opal_async_release_token(token); 70 return rc; 71 } 72 73 static int i2c_opal_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 74 int num) 75 { 76 unsigned long opal_id = (unsigned long)adap->algo_data; 77 struct opal_i2c_request req; 78 int rc, i; 79 80 /* We only support fairly simple combinations here of one 81 * or two messages 82 */ 83 memset(&req, 0, sizeof(req)); 84 switch(num) { 85 case 1: 86 req.type = (msgs[0].flags & I2C_M_RD) ? 87 OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE; 88 req.addr = cpu_to_be16(msgs[0].addr); 89 req.size = cpu_to_be32(msgs[0].len); 90 req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf)); 91 break; 92 case 2: 93 req.type = (msgs[1].flags & I2C_M_RD) ? 94 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 95 req.addr = cpu_to_be16(msgs[0].addr); 96 req.subaddr_sz = msgs[0].len; 97 for (i = 0; i < msgs[0].len; i++) 98 req.subaddr = (req.subaddr << 8) | msgs[0].buf[i]; 99 req.subaddr = cpu_to_be32(req.subaddr); 100 req.size = cpu_to_be32(msgs[1].len); 101 req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf)); 102 break; 103 } 104 105 rc = i2c_opal_send_request(opal_id, &req); 106 if (rc) 107 return rc; 108 109 return num; 110 } 111 112 static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr, 113 unsigned short flags, char read_write, 114 u8 command, int size, union i2c_smbus_data *data) 115 { 116 unsigned long opal_id = (unsigned long)adap->algo_data; 117 struct opal_i2c_request req; 118 u8 local[2]; 119 int rc; 120 121 memset(&req, 0, sizeof(req)); 122 123 req.addr = cpu_to_be16(addr); 124 switch (size) { 125 case I2C_SMBUS_BYTE: 126 req.buffer_ra = cpu_to_be64(__pa(&data->byte)); 127 req.size = cpu_to_be32(1); 128 fallthrough; 129 case I2C_SMBUS_QUICK: 130 req.type = (read_write == I2C_SMBUS_READ) ? 131 OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE; 132 break; 133 case I2C_SMBUS_BYTE_DATA: 134 req.buffer_ra = cpu_to_be64(__pa(&data->byte)); 135 req.size = cpu_to_be32(1); 136 req.subaddr = cpu_to_be32(command); 137 req.subaddr_sz = 1; 138 req.type = (read_write == I2C_SMBUS_READ) ? 139 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 140 break; 141 case I2C_SMBUS_WORD_DATA: 142 if (!read_write) { 143 local[0] = data->word & 0xff; 144 local[1] = (data->word >> 8) & 0xff; 145 } 146 req.buffer_ra = cpu_to_be64(__pa(local)); 147 req.size = cpu_to_be32(2); 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_I2C_BLOCK_DATA: 154 req.buffer_ra = cpu_to_be64(__pa(&data->block[1])); 155 req.size = cpu_to_be32(data->block[0]); 156 req.subaddr = cpu_to_be32(command); 157 req.subaddr_sz = 1; 158 req.type = (read_write == I2C_SMBUS_READ) ? 159 OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; 160 break; 161 default: 162 return -EINVAL; 163 } 164 165 rc = i2c_opal_send_request(opal_id, &req); 166 if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) { 167 data->word = ((u16)local[1]) << 8; 168 data->word |= local[0]; 169 } 170 171 return rc; 172 } 173 174 static u32 i2c_opal_func(struct i2c_adapter *adapter) 175 { 176 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 177 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 178 I2C_FUNC_SMBUS_I2C_BLOCK; 179 } 180 181 static const struct i2c_algorithm i2c_opal_algo = { 182 .master_xfer = i2c_opal_master_xfer, 183 .smbus_xfer = i2c_opal_smbus_xfer, 184 .functionality = i2c_opal_func, 185 }; 186 187 /* 188 * For two messages, we basically support simple smbus transactions of a 189 * write-then-anything. 190 */ 191 static const struct i2c_adapter_quirks i2c_opal_quirks = { 192 .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR, 193 .max_comb_1st_msg_len = 4, 194 }; 195 196 static int i2c_opal_probe(struct platform_device *pdev) 197 { 198 struct i2c_adapter *adapter; 199 const char *pname; 200 u32 opal_id; 201 int rc; 202 203 if (!pdev->dev.of_node) 204 return -ENODEV; 205 206 rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id); 207 if (rc) { 208 dev_err(&pdev->dev, "Missing ibm,opal-id property !\n"); 209 return -EIO; 210 } 211 212 adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL); 213 if (!adapter) 214 return -ENOMEM; 215 216 adapter->algo = &i2c_opal_algo; 217 adapter->algo_data = (void *)(unsigned long)opal_id; 218 adapter->quirks = &i2c_opal_quirks; 219 adapter->dev.parent = &pdev->dev; 220 adapter->dev.of_node = of_node_get(pdev->dev.of_node); 221 pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL); 222 if (pname) 223 strscpy(adapter->name, pname, sizeof(adapter->name)); 224 else 225 strscpy(adapter->name, "opal", sizeof(adapter->name)); 226 227 platform_set_drvdata(pdev, adapter); 228 rc = i2c_add_adapter(adapter); 229 if (rc) 230 dev_err(&pdev->dev, "Failed to register the i2c adapter\n"); 231 232 return rc; 233 } 234 235 static int i2c_opal_remove(struct platform_device *pdev) 236 { 237 struct i2c_adapter *adapter = platform_get_drvdata(pdev); 238 239 i2c_del_adapter(adapter); 240 241 return 0; 242 } 243 244 static const struct of_device_id i2c_opal_of_match[] = { 245 { 246 .compatible = "ibm,opal-i2c", 247 }, 248 { } 249 }; 250 MODULE_DEVICE_TABLE(of, i2c_opal_of_match); 251 252 static struct platform_driver i2c_opal_driver = { 253 .probe = i2c_opal_probe, 254 .remove = i2c_opal_remove, 255 .driver = { 256 .name = "i2c-opal", 257 .of_match_table = i2c_opal_of_match, 258 }, 259 }; 260 261 static int __init i2c_opal_init(void) 262 { 263 if (!firmware_has_feature(FW_FEATURE_OPAL)) 264 return -ENODEV; 265 266 return platform_driver_register(&i2c_opal_driver); 267 } 268 module_init(i2c_opal_init); 269 270 static void __exit i2c_opal_exit(void) 271 { 272 return platform_driver_unregister(&i2c_opal_driver); 273 } 274 module_exit(i2c_opal_exit); 275 276 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>"); 277 MODULE_DESCRIPTION("IBM OPAL I2C driver"); 278 MODULE_LICENSE("GPL"); 279