2 * I2C bridge driver for the Greybus "generic" I2C module.
4 * Copyright 2014 Google Inc.
5 * Copyright 2014 Linaro Ltd.
7 * Released under the GPLv2 only.
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/i2c.h>
18 struct gb_i2c_device {
19 struct gb_connection *connection;
20 struct gbphy_device *gbphy_dev;
24 struct i2c_adapter adapter;
28 * Map Greybus i2c functionality bits into Linux ones
30 static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
32 return gb_i2c_functionality; /* All bits the same for now */
35 static int gb_i2c_functionality_operation(struct gb_i2c_device *gb_i2c_dev)
37 struct gb_i2c_functionality_response response;
41 ret = gb_operation_sync(gb_i2c_dev->connection,
42 GB_I2C_TYPE_FUNCTIONALITY,
43 NULL, 0, &response, sizeof(response));
47 functionality = le32_to_cpu(response.functionality);
48 gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
54 * Map Linux i2c_msg flags into Greybus i2c transfer op flags.
56 static u16 gb_i2c_transfer_op_flags_map(u16 flags)
58 return flags; /* All flags the same for now */
62 gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
64 u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
66 op->addr = cpu_to_le16(msg->addr);
67 op->flags = cpu_to_le16(flags);
68 op->size = cpu_to_le16(msg->len);
71 static struct gb_operation *
72 gb_i2c_operation_create(struct gb_connection *connection,
73 struct i2c_msg *msgs, u32 msg_count)
75 struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
76 struct gb_i2c_transfer_request *request;
77 struct gb_operation *operation;
78 struct gb_i2c_transfer_op *op;
80 u32 data_out_size = 0;
87 if (msg_count > (u32)U16_MAX) {
88 dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
92 op_count = (u16)msg_count;
95 * In addition to space for all message descriptors we need
96 * to have enough to hold all outbound message data.
99 for (i = 0; i < msg_count; i++, msg++)
100 if (msg->flags & I2C_M_RD)
101 data_in_size += (u32)msg->len;
103 data_out_size += (u32)msg->len;
105 request_size = sizeof(*request);
106 request_size += msg_count * sizeof(*op);
107 request_size += data_out_size;
109 /* Response consists only of incoming data */
110 operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
111 request_size, data_in_size, GFP_KERNEL);
115 request = operation->request->payload;
116 request->op_count = cpu_to_le16(op_count);
117 /* Fill in the ops array */
118 op = &request->ops[0];
120 for (i = 0; i < msg_count; i++)
121 gb_i2c_fill_transfer_op(op++, msg++);
126 /* Copy over the outgoing data; it starts after the last op */
129 for (i = 0; i < msg_count; i++) {
130 if (!(msg->flags & I2C_M_RD)) {
131 memcpy(data, msg->buf, msg->len);
140 static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
141 struct gb_i2c_transfer_response *response)
143 struct i2c_msg *msg = msgs;
149 data = response->data;
150 for (i = 0; i < msg_count; i++) {
151 if (msg->flags & I2C_M_RD) {
152 memcpy(msg->buf, data, msg->len);
160 * Some i2c transfer operations return results that are expected.
162 static bool gb_i2c_expected_transfer_error(int errno)
164 return errno == -EAGAIN || errno == -ENODEV;
167 static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
168 struct i2c_msg *msgs, u32 msg_count)
170 struct gb_connection *connection = gb_i2c_dev->connection;
171 struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
172 struct gb_operation *operation;
175 operation = gb_i2c_operation_create(connection, msgs, msg_count);
179 ret = gb_operation_request_send_sync(operation);
181 struct gb_i2c_transfer_response *response;
183 response = operation->response->payload;
184 gb_i2c_decode_response(msgs, msg_count, response);
186 } else if (!gb_i2c_expected_transfer_error(ret)) {
187 dev_err(dev, "transfer operation failed (%d)\n", ret);
190 gb_operation_put(operation);
195 static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
198 struct gb_i2c_device *gb_i2c_dev;
200 gb_i2c_dev = i2c_get_adapdata(adap);
202 return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
207 static int gb_i2c_smbus_xfer(struct i2c_adapter *adap,
208 u16 addr, unsigned short flags, char read_write,
209 u8 command, int size, union i2c_smbus_data *data)
211 struct gb_i2c_device *gb_i2c_dev;
213 gb_i2c_dev = i2c_get_adapdata(adap);
219 static u32 gb_i2c_functionality(struct i2c_adapter *adap)
221 struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
223 return gb_i2c_dev->functionality;
226 static const struct i2c_algorithm gb_i2c_algorithm = {
227 .master_xfer = gb_i2c_master_xfer,
228 /* .smbus_xfer = gb_i2c_smbus_xfer, */
229 .functionality = gb_i2c_functionality,
233 * Do initial setup of the i2c device. This includes verifying we
234 * can support it (based on the protocol version it advertises).
235 * If that's OK, we get and cached its functionality bits.
237 * Note: gb_i2c_dev->connection is assumed to have been valid.
239 static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
241 /* Assume the functionality never changes, just get it once */
242 return gb_i2c_functionality_operation(gb_i2c_dev);
245 static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
246 const struct gbphy_device_id *id)
248 struct gb_connection *connection;
249 struct gb_i2c_device *gb_i2c_dev;
250 struct i2c_adapter *adapter;
253 gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
257 connection = gb_connection_create(gbphy_dev->bundle,
258 le16_to_cpu(gbphy_dev->cport_desc->id),
260 if (IS_ERR(connection)) {
261 ret = PTR_ERR(connection);
262 goto exit_i2cdev_free;
265 gb_i2c_dev->connection = connection;
266 gb_connection_set_data(connection, gb_i2c_dev);
267 gb_i2c_dev->gbphy_dev = gbphy_dev;
268 gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
270 ret = gb_connection_enable(connection);
272 goto exit_connection_destroy;
274 ret = gb_gbphy_get_version(connection);
276 goto exit_connection_disable;
278 ret = gb_i2c_device_setup(gb_i2c_dev);
280 goto exit_connection_disable;
282 /* Looks good; up our i2c adapter */
283 adapter = &gb_i2c_dev->adapter;
284 adapter->owner = THIS_MODULE;
285 adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
286 adapter->algo = &gb_i2c_algorithm;
287 /* adapter->algo_data = what? */
289 adapter->dev.parent = &gbphy_dev->dev;
290 snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
291 i2c_set_adapdata(adapter, gb_i2c_dev);
293 ret = i2c_add_adapter(adapter);
295 goto exit_connection_disable;
299 exit_connection_disable:
300 gb_connection_disable(connection);
301 exit_connection_destroy:
302 gb_connection_destroy(connection);
309 static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
311 struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
312 struct gb_connection *connection = gb_i2c_dev->connection;
314 i2c_del_adapter(&gb_i2c_dev->adapter);
315 gb_connection_disable(connection);
316 gb_connection_destroy(connection);
320 static const struct gbphy_device_id gb_i2c_id_table[] = {
321 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
324 MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
326 static struct gbphy_driver i2c_driver = {
328 .probe = gb_i2c_probe,
329 .remove = gb_i2c_remove,
330 .id_table = gb_i2c_id_table,
333 module_gbphy_driver(i2c_driver);
334 MODULE_LICENSE("GPL v2");