summaryrefslogtreecommitdiffstats
path: root/drivers/staging/greybus/i2c.c
blob: c2a50087000c716f2f6a1dcf3d27263e7549f266 (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
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
/*
 * I2C bridge driver for the Greybus "generic" I2C module.
 *
 * Copyright 2014 Google Inc.
 * Copyright 2014 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>

#include "greybus.h"
#include "gbphy.h"

struct gb_i2c_device {
	struct gb_connection	*connection;
	struct gbphy_device	*gbphy_dev;

	u32			functionality;

	struct i2c_adapter	adapter;
};

/*
 * Map Greybus i2c functionality bits into Linux ones
 */
static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
{
	return gb_i2c_functionality;	/* All bits the same for now */
}

static int gb_i2c_functionality_operation(struct gb_i2c_device *gb_i2c_dev)
{
	struct gb_i2c_functionality_response response;
	u32 functionality;
	int ret;

	ret = gb_operation_sync(gb_i2c_dev->connection,
				GB_I2C_TYPE_FUNCTIONALITY,
				NULL, 0, &response, sizeof(response));
	if (ret)
		return ret;

	functionality = le32_to_cpu(response.functionality);
	gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);

	return 0;
}

/*
 * Map Linux i2c_msg flags into Greybus i2c transfer op flags.
 */
static u16 gb_i2c_transfer_op_flags_map(u16 flags)
{
	return flags;	/* All flags the same for now */
}

static void
gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
{
	u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);

	op->addr = cpu_to_le16(msg->addr);
	op->flags = cpu_to_le16(flags);
	op->size = cpu_to_le16(msg->len);
}

static struct gb_operation *
gb_i2c_operation_create(struct gb_connection *connection,
			struct i2c_msg *msgs, u32 msg_count)
{
	struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
	struct gb_i2c_transfer_request *request;
	struct gb_operation *operation;
	struct gb_i2c_transfer_op *op;
	struct i2c_msg *msg;
	u32 data_out_size = 0;
	u32 data_in_size = 0;
	size_t request_size;
	void *data;
	u16 op_count;
	u32 i;

	if (msg_count > (u32)U16_MAX) {
		dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
			msg_count);
		return NULL;
	}
	op_count = (u16)msg_count;

	/*
	 * In addition to space for all message descriptors we need
	 * to have enough to hold all outbound message data.
	 */
	msg = msgs;
	for (i = 0; i < msg_count; i++, msg++)
		if (msg->flags & I2C_M_RD)
			data_in_size += (u32)msg->len;
		else
			data_out_size += (u32)msg->len;

	request_size = sizeof(*request);
	request_size += msg_count * sizeof(*op);
	request_size += data_out_size;

	/* Response consists only of incoming data */
	operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
				request_size, data_in_size, GFP_KERNEL);
	if (!operation)
		return NULL;

	request = operation->request->payload;
	request->op_count = cpu_to_le16(op_count);
	/* Fill in the ops array */
	op = &request->ops[0];
	msg = msgs;
	for (i = 0; i < msg_count; i++)
		gb_i2c_fill_transfer_op(op++, msg++);

	if (!data_out_size)
		return operation;

	/* Copy over the outgoing data; it starts after the last op */
	data = op;
	msg = msgs;
	for (i = 0; i < msg_count; i++) {
		if (!(msg->flags & I2C_M_RD)) {
			memcpy(data, msg->buf, msg->len);
			data += msg->len;
		}
		msg++;
	}

	return operation;
}

static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
				struct gb_i2c_transfer_response *response)
{
	struct i2c_msg *msg = msgs;
	u8 *data;
	u32 i;

	if (!response)
		return;
	data = response->data;
	for (i = 0; i < msg_count; i++) {
		if (msg->flags & I2C_M_RD) {
			memcpy(msg->buf, data, msg->len);
			data += msg->len;
		}
		msg++;
	}
}

/*
 * Some i2c transfer operations return results that are expected.
 */
static bool gb_i2c_expected_transfer_error(int errno)
{
	return errno == -EAGAIN || errno == -ENODEV;
}

static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
					struct i2c_msg *msgs, u32 msg_count)
{
	struct gb_connection *connection = gb_i2c_dev->connection;
	struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
	struct gb_operation *operation;
	int ret;

	operation = gb_i2c_operation_create(connection, msgs, msg_count);
	if (!operation)
		return -ENOMEM;

	ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
	if (ret)
		goto exit_operation_put;

	ret = gb_operation_request_send_sync(operation);
	if (!ret) {
		struct gb_i2c_transfer_response *response;

		response = operation->response->payload;
		gb_i2c_decode_response(msgs, msg_count, response);
		ret = msg_count;
	} else if (!gb_i2c_expected_transfer_error(ret)) {
		dev_err(dev, "transfer operation failed (%d)\n", ret);
	}

	gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);

exit_operation_put:
	gb_operation_put(operation);

	return ret;
}

static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
		int msg_count)
{
	struct gb_i2c_device *gb_i2c_dev;

	gb_i2c_dev = i2c_get_adapdata(adap);

	return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
}

#if 0
/* Later */
static int gb_i2c_smbus_xfer(struct i2c_adapter *adap,
			u16 addr, unsigned short flags, char read_write,
			u8 command, int size, union i2c_smbus_data *data)
{
	struct gb_i2c_device *gb_i2c_dev;

	gb_i2c_dev = i2c_get_adapdata(adap);

	return 0;
}
#endif

static u32 gb_i2c_functionality(struct i2c_adapter *adap)
{
	struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);

	return gb_i2c_dev->functionality;
}

static const struct i2c_algorithm gb_i2c_algorithm = {
	.master_xfer	= gb_i2c_master_xfer,
	/* .smbus_xfer	= gb_i2c_smbus_xfer, */
	.functionality	= gb_i2c_functionality,
};

/*
 * Do initial setup of the i2c device.  This includes verifying we
 * can support it (based on the protocol version it advertises).
 * If that's OK, we get and cached its functionality bits.
 *
 * Note: gb_i2c_dev->connection is assumed to have been valid.
 */
static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
{
	/* Assume the functionality never changes, just get it once */
	return gb_i2c_functionality_operation(gb_i2c_dev);
}

static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
			 const struct gbphy_device_id *id)
{
	struct gb_connection *connection;
	struct gb_i2c_device *gb_i2c_dev;
	struct i2c_adapter *adapter;
	int ret;

	gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
	if (!gb_i2c_dev)
		return -ENOMEM;

	connection = gb_connection_create(gbphy_dev->bundle,
					  le16_to_cpu(gbphy_dev->cport_desc->id),
					  NULL);
	if (IS_ERR(connection)) {
		ret = PTR_ERR(connection);
		goto exit_i2cdev_free;
	}

	gb_i2c_dev->connection = connection;
	gb_connection_set_data(connection, gb_i2c_dev);
	gb_i2c_dev->gbphy_dev = gbphy_dev;
	gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);

	ret = gb_connection_enable(connection);
	if (ret)
		goto exit_connection_destroy;

	ret = gb_i2c_device_setup(gb_i2c_dev);
	if (ret)
		goto exit_connection_disable;

	/* Looks good; up our i2c adapter */
	adapter = &gb_i2c_dev->adapter;
	adapter->owner = THIS_MODULE;
	adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
	adapter->algo = &gb_i2c_algorithm;
	/* adapter->algo_data = what? */

	adapter->dev.parent = &gbphy_dev->dev;
	snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
	i2c_set_adapdata(adapter, gb_i2c_dev);

	ret = i2c_add_adapter(adapter);
	if (ret)
		goto exit_connection_disable;

	gbphy_runtime_put_autosuspend(gbphy_dev);
	return 0;

exit_connection_disable:
	gb_connection_disable(connection);
exit_connection_destroy:
	gb_connection_destroy(connection);
exit_i2cdev_free:
	kfree(gb_i2c_dev);

	return ret;
}

static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
{
	struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
	struct gb_connection *connection = gb_i2c_dev->connection;
	int ret;

	ret = gbphy_runtime_get_sync(gbphy_dev);
	if (ret)
		gbphy_runtime_get_noresume(gbphy_dev);

	i2c_del_adapter(&gb_i2c_dev->adapter);
	gb_connection_disable(connection);
	gb_connection_destroy(connection);
	kfree(gb_i2c_dev);
}

static const struct gbphy_device_id gb_i2c_id_table[] = {
	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
	{ },
};
MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);

static struct gbphy_driver i2c_driver = {
	.name		= "i2c",
	.probe		= gb_i2c_probe,
	.remove		= gb_i2c_remove,
	.id_table	= gb_i2c_id_table,
};

module_gbphy_driver(i2c_driver);
MODULE_LICENSE("GPL v2");