xref: /linux/drivers/i2c/busses/i2c-opal.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
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