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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * I2C bridge driver for the Greybus "generic" I2C module.
4 *
5 * Copyright 2014 Google Inc.
6 * Copyright 2014 Linaro Ltd.
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/i2c.h>
13#include <linux/greybus.h>
14
15#include "gbphy.h"
16
17struct gb_i2c_device {
18 struct gb_connection *connection;
19 struct gbphy_device *gbphy_dev;
20
21 u32 functionality;
22
23 struct i2c_adapter adapter;
24};
25
26/*
27 * Map Greybus i2c functionality bits into Linux ones
28 */
29static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
30{
31 return gb_i2c_functionality; /* All bits the same for now */
32}
33
34/*
35 * Do initial setup of the i2c device. This includes verifying we
36 * can support it (based on the protocol version it advertises).
37 * If that's OK, we get and cached its functionality bits.
38 *
39 * Note: gb_i2c_dev->connection is assumed to have been valid.
40 */
41static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
42{
43 struct gb_i2c_functionality_response response;
44 u32 functionality;
45 int ret;
46
47 ret = gb_operation_sync(gb_i2c_dev->connection,
48 GB_I2C_TYPE_FUNCTIONALITY,
49 NULL, 0, &response, sizeof(response));
50 if (ret)
51 return ret;
52
53 functionality = le32_to_cpu(response.functionality);
54 gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
55
56 return 0;
57}
58
59/*
60 * Map Linux i2c_msg flags into Greybus i2c transfer op flags.
61 */
62static u16 gb_i2c_transfer_op_flags_map(u16 flags)
63{
64 return flags; /* All flags the same for now */
65}
66
67static void
68gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
69{
70 u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
71
72 op->addr = cpu_to_le16(msg->addr);
73 op->flags = cpu_to_le16(flags);
74 op->size = cpu_to_le16(msg->len);
75}
76
77static struct gb_operation *
78gb_i2c_operation_create(struct gb_connection *connection,
79 struct i2c_msg *msgs, u32 msg_count)
80{
81 struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
82 struct gb_i2c_transfer_request *request;
83 struct gb_operation *operation;
84 struct gb_i2c_transfer_op *op;
85 struct i2c_msg *msg;
86 u32 data_out_size = 0;
87 u32 data_in_size = 0;
88 size_t request_size;
89 void *data;
90 u16 op_count;
91 u32 i;
92
93 if (msg_count > (u32)U16_MAX) {
94 dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
95 msg_count);
96 return NULL;
97 }
98 op_count = (u16)msg_count;
99
100 /*
101 * In addition to space for all message descriptors we need
102 * to have enough to hold all outbound message data.
103 */
104 msg = msgs;
105 for (i = 0; i < msg_count; i++, msg++)
106 if (msg->flags & I2C_M_RD)
107 data_in_size += (u32)msg->len;
108 else
109 data_out_size += (u32)msg->len;
110
111 request_size = sizeof(*request);
112 request_size += msg_count * sizeof(*op);
113 request_size += data_out_size;
114
115 /* Response consists only of incoming data */
116 operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
117 request_size, data_in_size, GFP_KERNEL);
118 if (!operation)
119 return NULL;
120
121 request = operation->request->payload;
122 request->op_count = cpu_to_le16(op_count);
123 /* Fill in the ops array */
124 op = &request->ops[0];
125 msg = msgs;
126 for (i = 0; i < msg_count; i++)
127 gb_i2c_fill_transfer_op(op++, msg++);
128
129 if (!data_out_size)
130 return operation;
131
132 /* Copy over the outgoing data; it starts after the last op */
133 data = op;
134 msg = msgs;
135 for (i = 0; i < msg_count; i++) {
136 if (!(msg->flags & I2C_M_RD)) {
137 memcpy(data, msg->buf, msg->len);
138 data += msg->len;
139 }
140 msg++;
141 }
142
143 return operation;
144}
145
146static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
147 struct gb_i2c_transfer_response *response)
148{
149 struct i2c_msg *msg = msgs;
150 u8 *data;
151 u32 i;
152
153 if (!response)
154 return;
155 data = response->data;
156 for (i = 0; i < msg_count; i++) {
157 if (msg->flags & I2C_M_RD) {
158 memcpy(msg->buf, data, msg->len);
159 data += msg->len;
160 }
161 msg++;
162 }
163}
164
165/*
166 * Some i2c transfer operations return results that are expected.
167 */
168static bool gb_i2c_expected_transfer_error(int errno)
169{
170 return errno == -EAGAIN || errno == -ENODEV;
171}
172
173static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
174 struct i2c_msg *msgs, u32 msg_count)
175{
176 struct gb_connection *connection = gb_i2c_dev->connection;
177 struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
178 struct gb_operation *operation;
179 int ret;
180
181 operation = gb_i2c_operation_create(connection, msgs, msg_count);
182 if (!operation)
183 return -ENOMEM;
184
185 ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
186 if (ret)
187 goto exit_operation_put;
188
189 ret = gb_operation_request_send_sync(operation);
190 if (!ret) {
191 struct gb_i2c_transfer_response *response;
192
193 response = operation->response->payload;
194 gb_i2c_decode_response(msgs, msg_count, response);
195 ret = msg_count;
196 } else if (!gb_i2c_expected_transfer_error(ret)) {
197 dev_err(dev, "transfer operation failed (%d)\n", ret);
198 }
199
200 gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);
201
202exit_operation_put:
203 gb_operation_put(operation);
204
205 return ret;
206}
207
208static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
209 int msg_count)
210{
211 struct gb_i2c_device *gb_i2c_dev;
212
213 gb_i2c_dev = i2c_get_adapdata(adap);
214
215 return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
216}
217
218static u32 gb_i2c_functionality(struct i2c_adapter *adap)
219{
220 struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
221
222 return gb_i2c_dev->functionality;
223}
224
225static const struct i2c_algorithm gb_i2c_algorithm = {
226 .master_xfer = gb_i2c_master_xfer,
227 .functionality = gb_i2c_functionality,
228};
229
230static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
231 const struct gbphy_device_id *id)
232{
233 struct gb_connection *connection;
234 struct gb_i2c_device *gb_i2c_dev;
235 struct i2c_adapter *adapter;
236 int ret;
237
238 gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
239 if (!gb_i2c_dev)
240 return -ENOMEM;
241
242 connection =
243 gb_connection_create(gbphy_dev->bundle,
244 le16_to_cpu(gbphy_dev->cport_desc->id),
245 NULL);
246 if (IS_ERR(connection)) {
247 ret = PTR_ERR(connection);
248 goto exit_i2cdev_free;
249 }
250
251 gb_i2c_dev->connection = connection;
252 gb_connection_set_data(connection, gb_i2c_dev);
253 gb_i2c_dev->gbphy_dev = gbphy_dev;
254 gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
255
256 ret = gb_connection_enable(connection);
257 if (ret)
258 goto exit_connection_destroy;
259
260 ret = gb_i2c_device_setup(gb_i2c_dev);
261 if (ret)
262 goto exit_connection_disable;
263
264 /* Looks good; up our i2c adapter */
265 adapter = &gb_i2c_dev->adapter;
266 adapter->owner = THIS_MODULE;
267 adapter->class = I2C_CLASS_HWMON;
268 adapter->algo = &gb_i2c_algorithm;
269
270 adapter->dev.parent = &gbphy_dev->dev;
271 snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
272 i2c_set_adapdata(adapter, gb_i2c_dev);
273
274 ret = i2c_add_adapter(adapter);
275 if (ret)
276 goto exit_connection_disable;
277
278 gbphy_runtime_put_autosuspend(gbphy_dev);
279 return 0;
280
281exit_connection_disable:
282 gb_connection_disable(connection);
283exit_connection_destroy:
284 gb_connection_destroy(connection);
285exit_i2cdev_free:
286 kfree(gb_i2c_dev);
287
288 return ret;
289}
290
291static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
292{
293 struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
294 struct gb_connection *connection = gb_i2c_dev->connection;
295 int ret;
296
297 ret = gbphy_runtime_get_sync(gbphy_dev);
298 if (ret)
299 gbphy_runtime_get_noresume(gbphy_dev);
300
301 i2c_del_adapter(&gb_i2c_dev->adapter);
302 gb_connection_disable(connection);
303 gb_connection_destroy(connection);
304 kfree(gb_i2c_dev);
305}
306
307static const struct gbphy_device_id gb_i2c_id_table[] = {
308 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
309 { },
310};
311MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
312
313static struct gbphy_driver i2c_driver = {
314 .name = "i2c",
315 .probe = gb_i2c_probe,
316 .remove = gb_i2c_remove,
317 .id_table = gb_i2c_id_table,
318};
319
320module_gbphy_driver(i2c_driver);
321MODULE_DESCRIPTION("I2C bridge driver for the Greybus 'generic' I2C module");
322MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * I2C bridge driver for the Greybus "generic" I2C module.
4 *
5 * Copyright 2014 Google Inc.
6 * Copyright 2014 Linaro Ltd.
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/i2c.h>
13#include <linux/greybus.h>
14
15#include "gbphy.h"
16
17struct gb_i2c_device {
18 struct gb_connection *connection;
19 struct gbphy_device *gbphy_dev;
20
21 u32 functionality;
22
23 struct i2c_adapter adapter;
24};
25
26/*
27 * Map Greybus i2c functionality bits into Linux ones
28 */
29static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
30{
31 return gb_i2c_functionality; /* All bits the same for now */
32}
33
34/*
35 * Do initial setup of the i2c device. This includes verifying we
36 * can support it (based on the protocol version it advertises).
37 * If that's OK, we get and cached its functionality bits.
38 *
39 * Note: gb_i2c_dev->connection is assumed to have been valid.
40 */
41static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
42{
43 struct gb_i2c_functionality_response response;
44 u32 functionality;
45 int ret;
46
47 ret = gb_operation_sync(gb_i2c_dev->connection,
48 GB_I2C_TYPE_FUNCTIONALITY,
49 NULL, 0, &response, sizeof(response));
50 if (ret)
51 return ret;
52
53 functionality = le32_to_cpu(response.functionality);
54 gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
55
56 return 0;
57}
58
59/*
60 * Map Linux i2c_msg flags into Greybus i2c transfer op flags.
61 */
62static u16 gb_i2c_transfer_op_flags_map(u16 flags)
63{
64 return flags; /* All flags the same for now */
65}
66
67static void
68gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
69{
70 u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
71
72 op->addr = cpu_to_le16(msg->addr);
73 op->flags = cpu_to_le16(flags);
74 op->size = cpu_to_le16(msg->len);
75}
76
77static struct gb_operation *
78gb_i2c_operation_create(struct gb_connection *connection,
79 struct i2c_msg *msgs, u32 msg_count)
80{
81 struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
82 struct gb_i2c_transfer_request *request;
83 struct gb_operation *operation;
84 struct gb_i2c_transfer_op *op;
85 struct i2c_msg *msg;
86 u32 data_out_size = 0;
87 u32 data_in_size = 0;
88 size_t request_size;
89 void *data;
90 u16 op_count;
91 u32 i;
92
93 if (msg_count > (u32)U16_MAX) {
94 dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
95 msg_count);
96 return NULL;
97 }
98 op_count = (u16)msg_count;
99
100 /*
101 * In addition to space for all message descriptors we need
102 * to have enough to hold all outbound message data.
103 */
104 msg = msgs;
105 for (i = 0; i < msg_count; i++, msg++)
106 if (msg->flags & I2C_M_RD)
107 data_in_size += (u32)msg->len;
108 else
109 data_out_size += (u32)msg->len;
110
111 request_size = sizeof(*request);
112 request_size += msg_count * sizeof(*op);
113 request_size += data_out_size;
114
115 /* Response consists only of incoming data */
116 operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
117 request_size, data_in_size, GFP_KERNEL);
118 if (!operation)
119 return NULL;
120
121 request = operation->request->payload;
122 request->op_count = cpu_to_le16(op_count);
123 /* Fill in the ops array */
124 op = &request->ops[0];
125 msg = msgs;
126 for (i = 0; i < msg_count; i++)
127 gb_i2c_fill_transfer_op(op++, msg++);
128
129 if (!data_out_size)
130 return operation;
131
132 /* Copy over the outgoing data; it starts after the last op */
133 data = op;
134 msg = msgs;
135 for (i = 0; i < msg_count; i++) {
136 if (!(msg->flags & I2C_M_RD)) {
137 memcpy(data, msg->buf, msg->len);
138 data += msg->len;
139 }
140 msg++;
141 }
142
143 return operation;
144}
145
146static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
147 struct gb_i2c_transfer_response *response)
148{
149 struct i2c_msg *msg = msgs;
150 u8 *data;
151 u32 i;
152
153 if (!response)
154 return;
155 data = response->data;
156 for (i = 0; i < msg_count; i++) {
157 if (msg->flags & I2C_M_RD) {
158 memcpy(msg->buf, data, msg->len);
159 data += msg->len;
160 }
161 msg++;
162 }
163}
164
165/*
166 * Some i2c transfer operations return results that are expected.
167 */
168static bool gb_i2c_expected_transfer_error(int errno)
169{
170 return errno == -EAGAIN || errno == -ENODEV;
171}
172
173static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
174 struct i2c_msg *msgs, u32 msg_count)
175{
176 struct gb_connection *connection = gb_i2c_dev->connection;
177 struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
178 struct gb_operation *operation;
179 int ret;
180
181 operation = gb_i2c_operation_create(connection, msgs, msg_count);
182 if (!operation)
183 return -ENOMEM;
184
185 ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
186 if (ret)
187 goto exit_operation_put;
188
189 ret = gb_operation_request_send_sync(operation);
190 if (!ret) {
191 struct gb_i2c_transfer_response *response;
192
193 response = operation->response->payload;
194 gb_i2c_decode_response(msgs, msg_count, response);
195 ret = msg_count;
196 } else if (!gb_i2c_expected_transfer_error(ret)) {
197 dev_err(dev, "transfer operation failed (%d)\n", ret);
198 }
199
200 gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);
201
202exit_operation_put:
203 gb_operation_put(operation);
204
205 return ret;
206}
207
208static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
209 int msg_count)
210{
211 struct gb_i2c_device *gb_i2c_dev;
212
213 gb_i2c_dev = i2c_get_adapdata(adap);
214
215 return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
216}
217
218static u32 gb_i2c_functionality(struct i2c_adapter *adap)
219{
220 struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
221
222 return gb_i2c_dev->functionality;
223}
224
225static const struct i2c_algorithm gb_i2c_algorithm = {
226 .master_xfer = gb_i2c_master_xfer,
227 .functionality = gb_i2c_functionality,
228};
229
230static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
231 const struct gbphy_device_id *id)
232{
233 struct gb_connection *connection;
234 struct gb_i2c_device *gb_i2c_dev;
235 struct i2c_adapter *adapter;
236 int ret;
237
238 gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
239 if (!gb_i2c_dev)
240 return -ENOMEM;
241
242 connection =
243 gb_connection_create(gbphy_dev->bundle,
244 le16_to_cpu(gbphy_dev->cport_desc->id),
245 NULL);
246 if (IS_ERR(connection)) {
247 ret = PTR_ERR(connection);
248 goto exit_i2cdev_free;
249 }
250
251 gb_i2c_dev->connection = connection;
252 gb_connection_set_data(connection, gb_i2c_dev);
253 gb_i2c_dev->gbphy_dev = gbphy_dev;
254 gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
255
256 ret = gb_connection_enable(connection);
257 if (ret)
258 goto exit_connection_destroy;
259
260 ret = gb_i2c_device_setup(gb_i2c_dev);
261 if (ret)
262 goto exit_connection_disable;
263
264 /* Looks good; up our i2c adapter */
265 adapter = &gb_i2c_dev->adapter;
266 adapter->owner = THIS_MODULE;
267 adapter->class = I2C_CLASS_HWMON;
268 adapter->algo = &gb_i2c_algorithm;
269
270 adapter->dev.parent = &gbphy_dev->dev;
271 snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
272 i2c_set_adapdata(adapter, gb_i2c_dev);
273
274 ret = i2c_add_adapter(adapter);
275 if (ret)
276 goto exit_connection_disable;
277
278 gbphy_runtime_put_autosuspend(gbphy_dev);
279 return 0;
280
281exit_connection_disable:
282 gb_connection_disable(connection);
283exit_connection_destroy:
284 gb_connection_destroy(connection);
285exit_i2cdev_free:
286 kfree(gb_i2c_dev);
287
288 return ret;
289}
290
291static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
292{
293 struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
294 struct gb_connection *connection = gb_i2c_dev->connection;
295 int ret;
296
297 ret = gbphy_runtime_get_sync(gbphy_dev);
298 if (ret)
299 gbphy_runtime_get_noresume(gbphy_dev);
300
301 i2c_del_adapter(&gb_i2c_dev->adapter);
302 gb_connection_disable(connection);
303 gb_connection_destroy(connection);
304 kfree(gb_i2c_dev);
305}
306
307static const struct gbphy_device_id gb_i2c_id_table[] = {
308 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
309 { },
310};
311MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
312
313static struct gbphy_driver i2c_driver = {
314 .name = "i2c",
315 .probe = gb_i2c_probe,
316 .remove = gb_i2c_remove,
317 .id_table = gb_i2c_id_table,
318};
319
320module_gbphy_driver(i2c_driver);
321MODULE_LICENSE("GPL v2");