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
i2c_opal_translate_error(int rc)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
i2c_opal_send_request(u32 bus_id,struct opal_i2c_request * req)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
i2c_opal_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)73 static 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 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
i2c_opal_smbus_xfer(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)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
i2c_opal_func(struct i2c_adapter * adapter)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 .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 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
i2c_opal_probe(struct platform_device * pdev)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
i2c_opal_remove(struct platform_device * pdev)235 static 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
242 static const struct of_device_id i2c_opal_of_match[] = {
243 {
244 .compatible = "ibm,opal-i2c",
245 },
246 { }
247 };
248 MODULE_DEVICE_TABLE(of, i2c_opal_of_match);
249
250 static 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
i2c_opal_init(void)259 static 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 }
266 module_init(i2c_opal_init);
267
i2c_opal_exit(void)268 static void __exit i2c_opal_exit(void)
269 {
270 return platform_driver_unregister(&i2c_opal_driver);
271 }
272 module_exit(i2c_opal_exit);
273
274 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
275 MODULE_DESCRIPTION("IBM OPAL I2C driver");
276 MODULE_LICENSE("GPL");
277