summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-opal.c
blob: 75dd6d04124128957e95a2bf8a0d1b18eeda34dc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
 * IBM OPAL I2C driver
 * Copyright (C) 2014 IBM
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.
 */

#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <asm/firmware.h>
#include <asm/opal.h>

static int i2c_opal_translate_error(int rc)
{
	switch (rc) {
	case OPAL_NO_MEM:
		return -ENOMEM;
	case OPAL_PARAMETER:
		return -EINVAL;
	case OPAL_I2C_ARBT_LOST:
		return -EAGAIN;
	case OPAL_I2C_TIMEOUT:
		return -ETIMEDOUT;
	case OPAL_I2C_NACK_RCVD:
		return -ENXIO;
	case OPAL_I2C_STOP_ERR:
		return -EBUSY;
	default:
		return -EIO;
	}
}

static int i2c_opal_send_request(u32 bus_id, struct opal_i2c_request *req)
{
	struct opal_msg msg;
	int token, rc;

	token = opal_async_get_token_interruptible();
	if (token < 0) {
		if (token != -ERESTARTSYS)
			pr_err("Failed to get the async token\n");

		return token;
	}

	rc = opal_i2c_request(token, bus_id, req);
	if (rc != OPAL_ASYNC_COMPLETION) {
		rc = i2c_opal_translate_error(rc);
		goto exit;
	}

	rc = opal_async_wait_response(token, &msg);
	if (rc)
		goto exit;

	rc = be64_to_cpu(msg.params[1]);
	if (rc != OPAL_SUCCESS) {
		rc = i2c_opal_translate_error(rc);
		goto exit;
	}

exit:
	opal_async_release_token(token);
	return rc;
}

static int i2c_opal_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
				int num)
{
	unsigned long opal_id = (unsigned long)adap->algo_data;
	struct opal_i2c_request req;
	int rc, i;

	/* We only support fairly simple combinations here of one
	 * or two messages
	 */
	memset(&req, 0, sizeof(req));
	switch(num) {
	case 0:
		return 0;
	case 1:
		req.type = (msgs[0].flags & I2C_M_RD) ?
			OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
		req.addr = cpu_to_be16(msgs[0].addr);
		req.size = cpu_to_be32(msgs[0].len);
		req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf));
		break;
	case 2:
		req.type = (msgs[1].flags & I2C_M_RD) ?
			OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
		req.addr = cpu_to_be16(msgs[0].addr);
		req.subaddr_sz = msgs[0].len;
		for (i = 0; i < msgs[0].len; i++)
			req.subaddr = (req.subaddr << 8) | msgs[0].buf[i];
		req.subaddr = cpu_to_be32(req.subaddr);
		req.size = cpu_to_be32(msgs[1].len);
		req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf));
		break;
	default:
		return -EOPNOTSUPP;
	}

	rc = i2c_opal_send_request(opal_id, &req);
	if (rc)
		return rc;

	return num;
}

static int 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)
{
	unsigned long opal_id = (unsigned long)adap->algo_data;
	struct opal_i2c_request req;
	u8 local[2];
	int rc;

	memset(&req, 0, sizeof(req));

	req.addr = cpu_to_be16(addr);
	switch (size) {
	case I2C_SMBUS_BYTE:
		req.buffer_ra = cpu_to_be64(__pa(&data->byte));
		req.size = cpu_to_be32(1);
		/* Fall through */
	case I2C_SMBUS_QUICK:
		req.type = (read_write == I2C_SMBUS_READ) ?
			OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
		break;
	case I2C_SMBUS_BYTE_DATA:
		req.buffer_ra = cpu_to_be64(__pa(&data->byte));
		req.size = cpu_to_be32(1);
		req.subaddr = cpu_to_be32(command);
		req.subaddr_sz = 1;
		req.type = (read_write == I2C_SMBUS_READ) ?
			OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
		break;
	case I2C_SMBUS_WORD_DATA:
		if (!read_write) {
			local[0] = data->word & 0xff;
			local[1] = (data->word >> 8) & 0xff;
		}
		req.buffer_ra = cpu_to_be64(__pa(local));
		req.size = cpu_to_be32(2);
		req.subaddr = cpu_to_be32(command);
		req.subaddr_sz = 1;
		req.type = (read_write == I2C_SMBUS_READ) ?
			OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
		break;
	case I2C_SMBUS_I2C_BLOCK_DATA:
		req.buffer_ra = cpu_to_be64(__pa(&data->block[1]));
		req.size = cpu_to_be32(data->block[0]);
		req.subaddr = cpu_to_be32(command);
		req.subaddr_sz = 1;
		req.type = (read_write == I2C_SMBUS_READ) ?
			OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
		break;
	default:
		return -EINVAL;
	}

	rc = i2c_opal_send_request(opal_id, &req);
	if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) {
		data->word = ((u16)local[1]) << 8;
		data->word |= local[0];
	}

	return rc;
}

static u32 i2c_opal_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
	       I2C_FUNC_SMBUS_I2C_BLOCK;
}

static const struct i2c_algorithm i2c_opal_algo = {
	.master_xfer	= i2c_opal_master_xfer,
	.smbus_xfer	= i2c_opal_smbus_xfer,
	.functionality	= i2c_opal_func,
};

/*
 * For two messages, we basically support simple smbus transactions of a
 * write-then-anything.
 */
static struct i2c_adapter_quirks i2c_opal_quirks = {
	.flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
	.max_comb_1st_msg_len = 4,
};

static int i2c_opal_probe(struct platform_device *pdev)
{
	struct i2c_adapter	*adapter;
	const char		*pname;
	u32			opal_id;
	int			rc;

	if (!pdev->dev.of_node)
		return -ENODEV;

	rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id);
	if (rc) {
		dev_err(&pdev->dev, "Missing ibm,opal-id property !\n");
		return -EIO;
	}

	adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
	if (!adapter)
		return -ENOMEM;

	adapter->algo = &i2c_opal_algo;
	adapter->algo_data = (void *)(unsigned long)opal_id;
	adapter->quirks = &i2c_opal_quirks;
	adapter->dev.parent = &pdev->dev;
	adapter->dev.of_node = of_node_get(pdev->dev.of_node);
	pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL);
	if (pname)
		strlcpy(adapter->name, pname, sizeof(adapter->name));
	else
		strlcpy(adapter->name, "opal", sizeof(adapter->name));

	platform_set_drvdata(pdev, adapter);
	rc = i2c_add_adapter(adapter);
	if (rc)
		dev_err(&pdev->dev, "Failed to register the i2c adapter\n");

	return rc;
}

static int i2c_opal_remove(struct platform_device *pdev)
{
	struct i2c_adapter *adapter = platform_get_drvdata(pdev);

	i2c_del_adapter(adapter);

	return 0;
}

static const struct of_device_id i2c_opal_of_match[] = {
	{
		.compatible = "ibm,opal-i2c",
	},
	{ }
};
MODULE_DEVICE_TABLE(of, i2c_opal_of_match);

static struct platform_driver i2c_opal_driver = {
	.probe	= i2c_opal_probe,
	.remove	= i2c_opal_remove,
	.driver	= {
		.name		= "i2c-opal",
		.of_match_table	= i2c_opal_of_match,
	},
};

static int __init i2c_opal_init(void)
{
	if (!firmware_has_feature(FW_FEATURE_OPAL))
		return -ENODEV;

	return platform_driver_register(&i2c_opal_driver);
}
module_init(i2c_opal_init);

static void __exit i2c_opal_exit(void)
{
	return platform_driver_unregister(&i2c_opal_driver);
}
module_exit(i2c_opal_exit);

MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("IBM OPAL I2C driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud