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
i2c_opal_translate_error(int rc)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
i2c_opal_send_request(u32 bus_id,struct opal_i2c_request * req)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
i2c_opal_master_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)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
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)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
i2c_opal_func(struct i2c_adapter * adapter)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
i2c_opal_probe(struct platform_device * pdev)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
i2c_opal_remove(struct platform_device * pdev)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
i2c_opal_init(void)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
i2c_opal_exit(void)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
