1 /* $NetBSD: linux_i2c.c,v 1.7 2022/05/22 18:41:14 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2015 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: linux_i2c.c,v 1.7 2022/05/22 18:41:14 riastradh Exp $");
34
35 #include <sys/types.h>
36 #include <sys/errno.h>
37 #include <sys/kmem.h>
38 #include <sys/queue.h> /* XXX include order botch: i2cvar.h needs */
39
40 #include <dev/i2c/i2cvar.h>
41 #include <dev/i2c/i2c_bitbang.h> /* XXX include order botch */
42
43 #include <linux/i2c.h>
44 #include <linux/i2c-algo-bit.h>
45
46 static int netbsd_i2c_transfer(i2c_tag_t, struct i2c_msg *, int);
47 static i2c_op_t linux_i2c_flags_op(uint16_t, bool);
48 static int linux_i2c_flags_flags(uint16_t);
49 static uint32_t linux_i2cbb_functionality(struct i2c_adapter *);
50 static int linux_i2cbb_xfer(struct i2c_adapter *, struct i2c_msg *, int);
51 static void linux_i2cbb_set_bits(void *, uint32_t);
52 static uint32_t linux_i2cbb_read_bits(void *);
53 static void linux_i2cbb_set_dir(void *, uint32_t);
54 static int linux_i2cbb_send_start(void *, int);
55 static int linux_i2cbb_send_stop(void *, int);
56 static int linux_i2cbb_initiate_xfer(void *, i2c_addr_t, int);
57 static int linux_i2cbb_read_byte(void *, uint8_t *, int);
58 static int linux_i2cbb_write_byte(void *, uint8_t, int);
59
60 /*
61 * Client operations: operations with a particular i2c slave device.
62 */
63
64 struct i2c_client *
i2c_new_device(struct i2c_adapter * adapter,const struct i2c_board_info * info)65 i2c_new_device(struct i2c_adapter *adapter, const struct i2c_board_info *info)
66 {
67 struct i2c_client *client;
68
69 client = kmem_alloc(sizeof(*client), KM_SLEEP);
70 client->adapter = adapter;
71 client->addr = info->addr;
72 client->flags = info->flags;
73
74 return client;
75 }
76
77 void
i2c_unregister_device(struct i2c_client * client)78 i2c_unregister_device(struct i2c_client *client)
79 {
80
81 kmem_free(client, sizeof(*client));
82 }
83
84 int
i2c_master_send(const struct i2c_client * client,const char * buf,int count)85 i2c_master_send(const struct i2c_client *client, const char *buf, int count)
86 {
87 struct i2c_msg msg = {
88 .addr = client->addr,
89 .flags = client->flags & I2C_M_TEN,
90 .len = count,
91 .buf = __UNCONST(buf),
92 };
93 int ret;
94
95 KASSERT(0 <= count);
96
97 ret = i2c_transfer(client->adapter, &msg, 1);
98 if (ret <= 0)
99 return ret;
100
101 return count;
102 }
103
104 int
i2c_master_recv(const struct i2c_client * client,char * buf,int count)105 i2c_master_recv(const struct i2c_client *client, char *buf, int count)
106 {
107 struct i2c_msg msg = {
108 .addr = client->addr,
109 .flags = (client->flags & I2C_M_TEN) | I2C_M_RD,
110 .len = count,
111 .buf = buf,
112 };
113 int ret;
114
115 ret = i2c_transfer(client->adapter, &msg, 1);
116 if (ret <= 0)
117 return ret;
118
119 return count;
120 }
121
122 /*
123 * Adapter operations: operations over an i2c bus via a particular
124 * controller.
125 */
126
127 int
__i2c_transfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int n)128 __i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n)
129 {
130 unsigned timeout = hz; /* XXX adapter->timeout */
131 unsigned start = getticks();
132 int ret, nretries = 0;
133
134 do {
135 ret = (*adapter->algo->master_xfer)(adapter, msgs, n);
136 if (ret != -EAGAIN)
137 break;
138 } while (nretries++ < adapter->retries &&
139 getticks() - start < timeout);
140
141 return ret;
142 }
143
144 int
i2c_transfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int n)145 i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n)
146 {
147 int ret;
148
149 if (adapter->lock_ops)
150 (*adapter->lock_ops->lock_bus)(adapter, 0);
151 ret = __i2c_transfer(adapter, msgs, n);
152 if (adapter->lock_ops)
153 (*adapter->lock_ops->unlock_bus)(adapter, 0);
154
155 return ret;
156 }
157
158 static int
netbsd_i2c_transfer(i2c_tag_t i2c,struct i2c_msg * msgs,int n)159 netbsd_i2c_transfer(i2c_tag_t i2c, struct i2c_msg *msgs, int n)
160 {
161 int i;
162 int error;
163
164 for (i = 0; i < n; i++) {
165 const i2c_op_t op = linux_i2c_flags_op(msgs[i].flags,
166 ((i + 1) == n));
167 const int flags = linux_i2c_flags_flags(msgs[i].flags);
168
169 switch (op) {
170 case I2C_OP_READ:
171 case I2C_OP_READ_WITH_STOP:
172 error = iic_exec(i2c, op, msgs[i].addr,
173 NULL, 0, msgs[i].buf, msgs[i].len, flags);
174 break;
175
176 case I2C_OP_WRITE:
177 case I2C_OP_WRITE_WITH_STOP:
178 error = iic_exec(i2c, op, msgs[i].addr,
179 msgs[i].buf, msgs[i].len, NULL, 0, flags);
180 break;
181
182 default:
183 error = EINVAL;
184 }
185
186 if (error)
187 /* XXX errno NetBSD->Linux */
188 return -error;
189 }
190
191 return n;
192 }
193
194 static i2c_op_t
linux_i2c_flags_op(uint16_t flags,bool stop)195 linux_i2c_flags_op(uint16_t flags, bool stop)
196 {
197
198 if (ISSET(flags, I2C_M_STOP))
199 stop = true;
200
201 if (ISSET(flags, I2C_M_RD))
202 return (stop? I2C_OP_READ_WITH_STOP : I2C_OP_READ);
203 else
204 return (stop? I2C_OP_WRITE_WITH_STOP : I2C_OP_WRITE);
205 }
206
207 static int
linux_i2c_flags_flags(uint16_t flags __unused)208 linux_i2c_flags_flags(uint16_t flags __unused)
209 {
210
211 return 0;
212 }
213
214 /* Bit-banging */
215
216 const struct i2c_algorithm i2c_bit_algo = {
217 .master_xfer = linux_i2cbb_xfer,
218 .functionality = linux_i2cbb_functionality,
219 };
220
221 static uint32_t
linux_i2cbb_functionality(struct i2c_adapter * adapter __unused)222 linux_i2cbb_functionality(struct i2c_adapter *adapter __unused)
223 {
224 uint32_t functions = 0;
225
226 functions |= I2C_FUNC_I2C;
227 functions |= I2C_FUNC_NOSTART;
228 functions |= I2C_FUNC_SMBUS_EMUL;
229 functions |= I2C_FUNC_SMBUS_READ_BLOCK_DATA;
230 functions |= I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
231 #if 0
232 functions |= I2C_FUNC_10BIT_ADDR;
233 functions |= I2C_FUNC_PROTOCOL_MANGLING;
234 #endif
235
236 return functions;
237 }
238
239 static int
linux_i2cbb_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int n)240 linux_i2cbb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n)
241 {
242 struct i2c_algo_bit_data *const abd = adapter->algo_data;
243 struct i2c_controller controller = {
244 .ic_cookie = abd,
245 .ic_send_start = linux_i2cbb_send_start,
246 .ic_send_stop = linux_i2cbb_send_stop,
247 .ic_initiate_xfer = linux_i2cbb_initiate_xfer,
248 .ic_read_byte = linux_i2cbb_read_byte,
249 .ic_write_byte = linux_i2cbb_write_byte,
250 };
251 i2c_tag_t i2c = &controller;
252 int error;
253
254 if (abd->pre_xfer) {
255 error = (*abd->pre_xfer)(adapter);
256 if (error)
257 return error;
258 }
259
260 error = netbsd_i2c_transfer(i2c, msgs, n);
261
262 if (abd->post_xfer)
263 (*abd->post_xfer)(adapter);
264
265 return error;
266 }
267
268 #define LI2CBB_SDA 0x01
269 #define LI2CBB_SCL 0x02
270 #define LI2CBB_INPUT 0x04
271 #define LI2CBB_OUTPUT 0x08
272
273 static struct i2c_bitbang_ops linux_i2cbb_ops = {
274 .ibo_set_bits = linux_i2cbb_set_bits,
275 .ibo_set_dir = linux_i2cbb_set_dir,
276 .ibo_read_bits = linux_i2cbb_read_bits,
277 .ibo_bits = {
278 [I2C_BIT_SDA] = LI2CBB_SDA,
279 [I2C_BIT_SCL] = LI2CBB_SCL,
280 [I2C_BIT_INPUT] = LI2CBB_INPUT,
281 [I2C_BIT_OUTPUT] = LI2CBB_OUTPUT,
282 },
283 };
284
285 static void
linux_i2cbb_set_bits(void * cookie,uint32_t bits)286 linux_i2cbb_set_bits(void *cookie, uint32_t bits)
287 {
288 struct i2c_algo_bit_data *const abd = cookie;
289
290 (*abd->setsda)(abd->data, (ISSET(bits, LI2CBB_SDA)? 1 : 0));
291 (*abd->setscl)(abd->data, (ISSET(bits, LI2CBB_SCL)? 1 : 0));
292 }
293
294 static uint32_t
linux_i2cbb_read_bits(void * cookie)295 linux_i2cbb_read_bits(void *cookie)
296 {
297 struct i2c_algo_bit_data *const abd = cookie;
298 uint32_t bits = 0;
299
300 if ((*abd->getsda)(abd->data))
301 bits |= LI2CBB_SDA;
302 if ((*abd->getscl)(abd->data))
303 bits |= LI2CBB_SCL;
304
305 return bits;
306 }
307
308 static void
linux_i2cbb_set_dir(void * cookie __unused,uint32_t bits __unused)309 linux_i2cbb_set_dir(void *cookie __unused, uint32_t bits __unused)
310 {
311 /* Linux doesn't do anything here... */
312 }
313
314 static int
linux_i2cbb_send_start(void * cookie,int flags)315 linux_i2cbb_send_start(void *cookie, int flags)
316 {
317
318 return i2c_bitbang_send_start(cookie, flags, &linux_i2cbb_ops);
319 }
320
321 static int
linux_i2cbb_send_stop(void * cookie,int flags)322 linux_i2cbb_send_stop(void *cookie, int flags)
323 {
324
325 return i2c_bitbang_send_stop(cookie, flags, &linux_i2cbb_ops);
326 }
327
328 static int
linux_i2cbb_initiate_xfer(void * cookie,i2c_addr_t addr,int flags)329 linux_i2cbb_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
330 {
331
332 return i2c_bitbang_initiate_xfer(cookie, addr, flags,
333 &linux_i2cbb_ops);
334 }
335
336 static int
linux_i2cbb_read_byte(void * cookie,uint8_t * bytep,int flags)337 linux_i2cbb_read_byte(void *cookie, uint8_t *bytep, int flags)
338 {
339
340 return i2c_bitbang_read_byte(cookie, bytep, flags, &linux_i2cbb_ops);
341 }
342
343 static int
linux_i2cbb_write_byte(void * cookie,uint8_t byte,int flags)344 linux_i2cbb_write_byte(void *cookie, uint8_t byte, int flags)
345 {
346
347 return i2c_bitbang_write_byte(cookie, byte, flags, &linux_i2cbb_ops);
348 }
349