1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Intel La Jolla Cove Adapter USB-I2C driver
4 *
5 * Copyright (c) 2023, Intel Corporation.
6 */
7
8 #include <linux/acpi.h>
9 #include <linux/auxiliary_bus.h>
10 #include <linux/bitfield.h>
11 #include <linux/bits.h>
12 #include <linux/dev_printk.h>
13 #include <linux/i2c.h>
14 #include <linux/module.h>
15 #include <linux/usb/ljca.h>
16
17 /* I2C init flags */
18 #define LJCA_I2C_INIT_FLAG_MODE BIT(0)
19 #define LJCA_I2C_INIT_FLAG_MODE_POLLING FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 0)
20 #define LJCA_I2C_INIT_FLAG_MODE_INTERRUPT FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 1)
21
22 #define LJCA_I2C_INIT_FLAG_ADDR_16BIT BIT(0)
23
24 #define LJCA_I2C_INIT_FLAG_FREQ GENMASK(2, 1)
25 #define LJCA_I2C_INIT_FLAG_FREQ_100K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 0)
26 #define LJCA_I2C_INIT_FLAG_FREQ_400K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 1)
27 #define LJCA_I2C_INIT_FLAG_FREQ_1M FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 2)
28
29 #define LJCA_I2C_BUF_SIZE 60u
30 #define LJCA_I2C_MAX_XFER_SIZE (LJCA_I2C_BUF_SIZE - sizeof(struct ljca_i2c_rw_packet))
31
32 /* I2C commands */
33 enum ljca_i2c_cmd {
34 LJCA_I2C_INIT = 1,
35 LJCA_I2C_XFER,
36 LJCA_I2C_START,
37 LJCA_I2C_STOP,
38 LJCA_I2C_READ,
39 LJCA_I2C_WRITE,
40 };
41
42 enum ljca_xfer_type {
43 LJCA_I2C_WRITE_XFER_TYPE,
44 LJCA_I2C_READ_XFER_TYPE,
45 };
46
47 /* I2C raw commands: Init/Start/Read/Write/Stop */
48 struct ljca_i2c_rw_packet {
49 u8 id;
50 __le16 len;
51 u8 data[] __counted_by(len);
52 } __packed;
53
54 struct ljca_i2c_dev {
55 struct ljca_client *ljca;
56 struct ljca_i2c_info *i2c_info;
57 struct i2c_adapter adap;
58
59 u8 obuf[LJCA_I2C_BUF_SIZE];
60 u8 ibuf[LJCA_I2C_BUF_SIZE];
61 };
62
ljca_i2c_init(struct ljca_i2c_dev * ljca_i2c,u8 id)63 static int ljca_i2c_init(struct ljca_i2c_dev *ljca_i2c, u8 id)
64 {
65 struct ljca_i2c_rw_packet *w_packet =
66 (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
67 int ret;
68
69 w_packet->id = id;
70 w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
71 w_packet->data[0] = LJCA_I2C_INIT_FLAG_FREQ_400K;
72
73 ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_INIT, (u8 *)w_packet,
74 struct_size(w_packet, data, 1), NULL, 0);
75
76 return ret < 0 ? ret : 0;
77 }
78
ljca_i2c_start(struct ljca_i2c_dev * ljca_i2c,u8 target_addr,enum ljca_xfer_type type)79 static int ljca_i2c_start(struct ljca_i2c_dev *ljca_i2c, u8 target_addr,
80 enum ljca_xfer_type type)
81 {
82 struct ljca_i2c_rw_packet *w_packet =
83 (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
84 struct ljca_i2c_rw_packet *r_packet =
85 (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
86 s16 rp_len;
87 int ret;
88
89 w_packet->id = ljca_i2c->i2c_info->id;
90 w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
91 w_packet->data[0] = (target_addr << 1) | type;
92
93 ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_START, (u8 *)w_packet,
94 struct_size(w_packet, data, 1), (u8 *)r_packet,
95 LJCA_I2C_BUF_SIZE);
96 if (ret < 0 || ret < sizeof(*r_packet))
97 return ret < 0 ? ret : -EIO;
98
99 rp_len = le16_to_cpu(r_packet->len);
100 if (rp_len < 0 || r_packet->id != w_packet->id) {
101 dev_dbg(&ljca_i2c->adap.dev,
102 "i2c start failed len: %d id: %d %d\n",
103 rp_len, r_packet->id, w_packet->id);
104 return -EIO;
105 }
106
107 return 0;
108 }
109
ljca_i2c_stop(struct ljca_i2c_dev * ljca_i2c)110 static void ljca_i2c_stop(struct ljca_i2c_dev *ljca_i2c)
111 {
112 struct ljca_i2c_rw_packet *w_packet =
113 (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
114 struct ljca_i2c_rw_packet *r_packet =
115 (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
116 s16 rp_len;
117 int ret;
118
119 w_packet->id = ljca_i2c->i2c_info->id;
120 w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
121 w_packet->data[0] = 0;
122
123 ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_STOP, (u8 *)w_packet,
124 struct_size(w_packet, data, 1), (u8 *)r_packet,
125 LJCA_I2C_BUF_SIZE);
126 if (ret < 0 || ret < sizeof(*r_packet)) {
127 dev_dbg(&ljca_i2c->adap.dev,
128 "i2c stop failed ret: %d id: %d\n",
129 ret, w_packet->id);
130 return;
131 }
132
133 rp_len = le16_to_cpu(r_packet->len);
134 if (rp_len < 0 || r_packet->id != w_packet->id)
135 dev_dbg(&ljca_i2c->adap.dev,
136 "i2c stop failed len: %d id: %d %d\n",
137 rp_len, r_packet->id, w_packet->id);
138 }
139
ljca_i2c_pure_read(struct ljca_i2c_dev * ljca_i2c,u8 * data,u8 len)140 static int ljca_i2c_pure_read(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
141 {
142 struct ljca_i2c_rw_packet *w_packet =
143 (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
144 struct ljca_i2c_rw_packet *r_packet =
145 (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
146 s16 rp_len;
147 int ret;
148
149 w_packet->id = ljca_i2c->i2c_info->id;
150 w_packet->len = cpu_to_le16(len);
151 w_packet->data[0] = 0;
152
153 ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_READ, (u8 *)w_packet,
154 struct_size(w_packet, data, 1), (u8 *)r_packet,
155 LJCA_I2C_BUF_SIZE);
156 if (ret < 0 || ret < sizeof(*r_packet))
157 return ret < 0 ? ret : -EIO;
158
159 rp_len = le16_to_cpu(r_packet->len);
160 if (rp_len != len || r_packet->id != w_packet->id) {
161 dev_dbg(&ljca_i2c->adap.dev,
162 "i2c raw read failed len: %d id: %d %d\n",
163 rp_len, r_packet->id, w_packet->id);
164 return -EIO;
165 }
166
167 memcpy(data, r_packet->data, len);
168
169 return 0;
170 }
171
ljca_i2c_read(struct ljca_i2c_dev * ljca_i2c,u8 target_addr,u8 * data,u8 len)172 static int ljca_i2c_read(struct ljca_i2c_dev *ljca_i2c, u8 target_addr, u8 *data,
173 u8 len)
174 {
175 int ret;
176
177 ret = ljca_i2c_start(ljca_i2c, target_addr, LJCA_I2C_READ_XFER_TYPE);
178 if (!ret)
179 ret = ljca_i2c_pure_read(ljca_i2c, data, len);
180
181 ljca_i2c_stop(ljca_i2c);
182
183 return ret;
184 }
185
ljca_i2c_pure_write(struct ljca_i2c_dev * ljca_i2c,u8 * data,u8 len)186 static int ljca_i2c_pure_write(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
187 {
188 struct ljca_i2c_rw_packet *w_packet =
189 (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
190 struct ljca_i2c_rw_packet *r_packet =
191 (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
192 s16 rplen;
193 int ret;
194
195 w_packet->id = ljca_i2c->i2c_info->id;
196 w_packet->len = cpu_to_le16(len);
197 memcpy(w_packet->data, data, len);
198
199 ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_WRITE, (u8 *)w_packet,
200 struct_size(w_packet, data, len), (u8 *)r_packet,
201 LJCA_I2C_BUF_SIZE);
202 if (ret < 0 || ret < sizeof(*r_packet))
203 return ret < 0 ? ret : -EIO;
204
205 rplen = le16_to_cpu(r_packet->len);
206 if (rplen != len || r_packet->id != w_packet->id) {
207 dev_dbg(&ljca_i2c->adap.dev,
208 "i2c write failed len: %d id: %d/%d\n",
209 rplen, r_packet->id, w_packet->id);
210 return -EIO;
211 }
212
213 return 0;
214 }
215
ljca_i2c_write(struct ljca_i2c_dev * ljca_i2c,u8 target_addr,u8 * data,u8 len)216 static int ljca_i2c_write(struct ljca_i2c_dev *ljca_i2c, u8 target_addr,
217 u8 *data, u8 len)
218 {
219 int ret;
220
221 ret = ljca_i2c_start(ljca_i2c, target_addr, LJCA_I2C_WRITE_XFER_TYPE);
222 if (!ret)
223 ret = ljca_i2c_pure_write(ljca_i2c, data, len);
224
225 ljca_i2c_stop(ljca_i2c);
226
227 return ret;
228 }
229
ljca_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msg,int num)230 static int ljca_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msg,
231 int num)
232 {
233 struct ljca_i2c_dev *ljca_i2c;
234 struct i2c_msg *cur_msg;
235 int i, ret;
236
237 ljca_i2c = i2c_get_adapdata(adapter);
238 if (!ljca_i2c)
239 return -EINVAL;
240
241 for (i = 0; i < num; i++) {
242 cur_msg = &msg[i];
243 if (cur_msg->flags & I2C_M_RD)
244 ret = ljca_i2c_read(ljca_i2c, cur_msg->addr,
245 cur_msg->buf, cur_msg->len);
246 else
247 ret = ljca_i2c_write(ljca_i2c, cur_msg->addr,
248 cur_msg->buf, cur_msg->len);
249
250 if (ret)
251 return ret;
252 }
253
254 return num;
255 }
256
ljca_i2c_func(struct i2c_adapter * adap)257 static u32 ljca_i2c_func(struct i2c_adapter *adap)
258 {
259 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
260 }
261
262 static const struct i2c_adapter_quirks ljca_i2c_quirks = {
263 .flags = I2C_AQ_NO_ZERO_LEN,
264 .max_read_len = LJCA_I2C_MAX_XFER_SIZE,
265 .max_write_len = LJCA_I2C_MAX_XFER_SIZE,
266 };
267
268 static const struct i2c_algorithm ljca_i2c_algo = {
269 .xfer = ljca_i2c_xfer,
270 .functionality = ljca_i2c_func,
271 };
272
ljca_i2c_probe(struct auxiliary_device * auxdev,const struct auxiliary_device_id * aux_dev_id)273 static int ljca_i2c_probe(struct auxiliary_device *auxdev,
274 const struct auxiliary_device_id *aux_dev_id)
275 {
276 struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
277 struct ljca_i2c_dev *ljca_i2c;
278 int ret;
279
280 ljca_i2c = devm_kzalloc(&auxdev->dev, sizeof(*ljca_i2c), GFP_KERNEL);
281 if (!ljca_i2c)
282 return -ENOMEM;
283
284 ljca_i2c->ljca = ljca;
285 ljca_i2c->i2c_info = dev_get_platdata(&auxdev->dev);
286
287 ljca_i2c->adap.owner = THIS_MODULE;
288 ljca_i2c->adap.class = I2C_CLASS_HWMON;
289 ljca_i2c->adap.algo = &ljca_i2c_algo;
290 ljca_i2c->adap.quirks = &ljca_i2c_quirks;
291 ljca_i2c->adap.dev.parent = &auxdev->dev;
292
293 snprintf(ljca_i2c->adap.name, sizeof(ljca_i2c->adap.name), "%s-%s-%d",
294 dev_name(&auxdev->dev), dev_name(auxdev->dev.parent),
295 ljca_i2c->i2c_info->id);
296
297 device_set_node(&ljca_i2c->adap.dev, dev_fwnode(&auxdev->dev));
298
299 i2c_set_adapdata(&ljca_i2c->adap, ljca_i2c);
300 auxiliary_set_drvdata(auxdev, ljca_i2c);
301
302 ret = ljca_i2c_init(ljca_i2c, ljca_i2c->i2c_info->id);
303 if (ret)
304 return dev_err_probe(&auxdev->dev, -EIO,
305 "i2c init failed id: %d\n",
306 ljca_i2c->i2c_info->id);
307
308 ret = devm_i2c_add_adapter(&auxdev->dev, &ljca_i2c->adap);
309 if (ret)
310 return ret;
311
312 if (has_acpi_companion(&ljca_i2c->adap.dev))
313 acpi_dev_clear_dependencies(ACPI_COMPANION(&ljca_i2c->adap.dev));
314
315 return 0;
316 }
317
ljca_i2c_remove(struct auxiliary_device * auxdev)318 static void ljca_i2c_remove(struct auxiliary_device *auxdev)
319 {
320 struct ljca_i2c_dev *ljca_i2c = auxiliary_get_drvdata(auxdev);
321
322 i2c_del_adapter(&ljca_i2c->adap);
323 }
324
325 static const struct auxiliary_device_id ljca_i2c_id_table[] = {
326 { "usb_ljca.ljca-i2c", 0 },
327 { /* sentinel */ }
328 };
329 MODULE_DEVICE_TABLE(auxiliary, ljca_i2c_id_table);
330
331 static struct auxiliary_driver ljca_i2c_driver = {
332 .probe = ljca_i2c_probe,
333 .remove = ljca_i2c_remove,
334 .id_table = ljca_i2c_id_table,
335 };
336 module_auxiliary_driver(ljca_i2c_driver);
337
338 MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
339 MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
340 MODULE_AUTHOR("Lixu Zhang <lixu.zhang@intel.com>");
341 MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-I2C driver");
342 MODULE_LICENSE("GPL");
343 MODULE_IMPORT_NS("LJCA");
344