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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * IBM OPAL I2C driver4 * Copyright (C) 2014 IBM5 */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 19static 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 39static 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 68exit:69 opal_async_release_token(token);70 return rc;71}72 73static int i2c_opal_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 one81 * or two messages82 */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 112static 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 174static 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 181static const struct i2c_algorithm i2c_opal_algo = {182 .xfer = i2c_opal_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 a189 * write-then-anything.190 */191static 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 196static 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 else225 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 235static void 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 242static const struct of_device_id i2c_opal_of_match[] = {243 {244 .compatible = "ibm,opal-i2c",245 },246 { }247};248MODULE_DEVICE_TABLE(of, i2c_opal_of_match);249 250static struct platform_driver i2c_opal_driver = {251 .probe = i2c_opal_probe,252 .remove_new = i2c_opal_remove,253 .driver = {254 .name = "i2c-opal",255 .of_match_table = i2c_opal_of_match,256 },257};258 259static int __init i2c_opal_init(void)260{261 if (!firmware_has_feature(FW_FEATURE_OPAL))262 return -ENODEV;263 264 return platform_driver_register(&i2c_opal_driver);265}266module_init(i2c_opal_init);267 268static void __exit i2c_opal_exit(void)269{270 return platform_driver_unregister(&i2c_opal_driver);271}272module_exit(i2c_opal_exit);273 274MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");275MODULE_DESCRIPTION("IBM OPAL I2C driver");276MODULE_LICENSE("GPL");277