linux_i2c.c revision 1.6
1 /* $NetBSD: linux_i2c.c,v 1.6 2021/12/19 11:49:12 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 1.6 2021/12/19 11:49:12 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 /* 62 * Client operations: operations with a particular i2c slave device. 63 */ 64 65 struct i2c_client * 66 i2c_new_device(struct i2c_adapter *adapter, const struct i2c_board_info *info) 67 { 68 struct i2c_client *client; 69 70 client = kmem_alloc(sizeof(*client), KM_SLEEP); 71 client->adapter = adapter; 72 client->addr = info->addr; 73 client->flags = info->flags; 74 75 return client; 76 } 77 78 void 79 i2c_unregister_device(struct i2c_client *client) 80 { 81 82 kmem_free(client, sizeof(*client)); 83 } 84 85 int 86 i2c_master_send(const struct i2c_client *client, const char *buf, int count) 87 { 88 struct i2c_msg msg = { 89 .addr = client->addr, 90 .flags = client->flags & I2C_M_TEN, 91 .len = count, 92 .buf = __UNCONST(buf), 93 }; 94 int ret; 95 96 KASSERT(0 <= count); 97 98 ret = i2c_transfer(client->adapter, &msg, 1); 99 if (ret <= 0) 100 return ret; 101 102 return count; 103 } 104 105 int 106 i2c_master_recv(const struct i2c_client *client, char *buf, int count) 107 { 108 struct i2c_msg msg = { 109 .addr = client->addr, 110 .flags = (client->flags & I2C_M_TEN) | I2C_M_RD, 111 .len = count, 112 .buf = buf, 113 }; 114 int ret; 115 116 ret = i2c_transfer(client->adapter, &msg, 1); 117 if (ret <= 0) 118 return ret; 119 120 return count; 121 } 122 123 /* 125 * Adapter operations: operations over an i2c bus via a particular 126 * controller. 127 */ 128 129 int 130 __i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 131 { 132 133 return (*adapter->algo->master_xfer)(adapter, msgs, n); 134 } 135 136 int 137 i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 138 { 139 int ret; 140 141 if (adapter->lock_ops) 142 (*adapter->lock_ops->lock_bus)(adapter, 0); 143 ret = __i2c_transfer(adapter, msgs, n); 144 if (adapter->lock_ops) 145 (*adapter->lock_ops->unlock_bus)(adapter, 0); 146 147 return ret; 148 } 149 150 static int 151 netbsd_i2c_transfer(i2c_tag_t i2c, struct i2c_msg *msgs, int n) 152 { 153 int i; 154 int error; 155 156 for (i = 0; i < n; i++) { 157 const i2c_op_t op = linux_i2c_flags_op(msgs[i].flags, 158 ((i + 1) == n)); 159 const int flags = linux_i2c_flags_flags(msgs[i].flags); 160 161 switch (op) { 162 case I2C_OP_READ: 163 case I2C_OP_READ_WITH_STOP: 164 error = iic_exec(i2c, op, msgs[i].addr, 165 NULL, 0, msgs[i].buf, msgs[i].len, flags); 166 break; 167 168 case I2C_OP_WRITE: 169 case I2C_OP_WRITE_WITH_STOP: 170 error = iic_exec(i2c, op, msgs[i].addr, 171 msgs[i].buf, msgs[i].len, NULL, 0, flags); 172 break; 173 174 default: 175 error = EINVAL; 176 } 177 178 if (error) 179 /* XXX errno NetBSD->Linux */ 180 return -error; 181 } 182 183 return n; 184 } 185 186 static i2c_op_t 187 linux_i2c_flags_op(uint16_t flags, bool stop) 188 { 189 190 if (ISSET(flags, I2C_M_STOP)) 191 stop = true; 192 193 if (ISSET(flags, I2C_M_RD)) 194 return (stop? I2C_OP_READ_WITH_STOP : I2C_OP_READ); 195 else 196 return (stop? I2C_OP_WRITE_WITH_STOP : I2C_OP_WRITE); 197 } 198 199 static int 200 linux_i2c_flags_flags(uint16_t flags __unused) 201 { 202 203 return 0; 204 } 205 206 /* Bit-banging */ 208 209 const struct i2c_algorithm i2c_bit_algo = { 210 .master_xfer = linux_i2cbb_xfer, 211 .functionality = linux_i2cbb_functionality, 212 }; 213 214 static uint32_t 215 linux_i2cbb_functionality(struct i2c_adapter *adapter __unused) 216 { 217 uint32_t functions = 0; 218 219 functions |= I2C_FUNC_I2C; 220 functions |= I2C_FUNC_NOSTART; 221 functions |= I2C_FUNC_SMBUS_EMUL; 222 functions |= I2C_FUNC_SMBUS_READ_BLOCK_DATA; 223 functions |= I2C_FUNC_SMBUS_BLOCK_PROC_CALL; 224 #if 0 225 functions |= I2C_FUNC_10BIT_ADDR; 226 functions |= I2C_FUNC_PROTOCOL_MANGLING; 227 #endif 228 229 return functions; 230 } 231 232 static int 233 linux_i2cbb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 234 { 235 struct i2c_algo_bit_data *const abd = adapter->algo_data; 236 struct i2c_controller controller = { 237 .ic_cookie = abd, 238 .ic_send_start = linux_i2cbb_send_start, 239 .ic_send_stop = linux_i2cbb_send_stop, 240 .ic_initiate_xfer = linux_i2cbb_initiate_xfer, 241 .ic_read_byte = linux_i2cbb_read_byte, 242 .ic_write_byte = linux_i2cbb_write_byte, 243 }; 244 i2c_tag_t i2c = &controller; 245 int error; 246 247 if (abd->pre_xfer) { 248 error = (*abd->pre_xfer)(adapter); 249 if (error) 250 return error; 251 } 252 253 error = netbsd_i2c_transfer(i2c, msgs, n); 254 255 if (abd->post_xfer) 256 (*abd->post_xfer)(adapter); 257 258 return error; 259 } 260 261 #define LI2CBB_SDA 0x01 263 #define LI2CBB_SCL 0x02 264 #define LI2CBB_INPUT 0x04 265 #define LI2CBB_OUTPUT 0x08 266 267 static struct i2c_bitbang_ops linux_i2cbb_ops = { 268 .ibo_set_bits = linux_i2cbb_set_bits, 269 .ibo_set_dir = linux_i2cbb_set_dir, 270 .ibo_read_bits = linux_i2cbb_read_bits, 271 .ibo_bits = { 272 [I2C_BIT_SDA] = LI2CBB_SDA, 273 [I2C_BIT_SCL] = LI2CBB_SCL, 274 [I2C_BIT_INPUT] = LI2CBB_INPUT, 275 [I2C_BIT_OUTPUT] = LI2CBB_OUTPUT, 276 }, 277 }; 278 279 static void 280 linux_i2cbb_set_bits(void *cookie, uint32_t bits) 281 { 282 struct i2c_algo_bit_data *const abd = cookie; 283 284 (*abd->setsda)(abd->data, (ISSET(bits, LI2CBB_SDA)? 1 : 0)); 285 (*abd->setscl)(abd->data, (ISSET(bits, LI2CBB_SCL)? 1 : 0)); 286 } 287 288 static uint32_t 289 linux_i2cbb_read_bits(void *cookie) 290 { 291 struct i2c_algo_bit_data *const abd = cookie; 292 uint32_t bits = 0; 293 294 if ((*abd->getsda)(abd->data)) 295 bits |= LI2CBB_SDA; 296 if ((*abd->getscl)(abd->data)) 297 bits |= LI2CBB_SCL; 298 299 return bits; 300 } 301 302 static void 303 linux_i2cbb_set_dir(void *cookie __unused, uint32_t bits __unused) 304 { 305 /* Linux doesn't do anything here... */ 306 } 307 308 static int 310 linux_i2cbb_send_start(void *cookie, int flags) 311 { 312 313 return i2c_bitbang_send_start(cookie, flags, &linux_i2cbb_ops); 314 } 315 316 static int 317 linux_i2cbb_send_stop(void *cookie, int flags) 318 { 319 320 return i2c_bitbang_send_stop(cookie, flags, &linux_i2cbb_ops); 321 } 322 323 static int 324 linux_i2cbb_initiate_xfer(void *cookie, i2c_addr_t addr, int flags) 325 { 326 327 return i2c_bitbang_initiate_xfer(cookie, addr, flags, 328 &linux_i2cbb_ops); 329 } 330 331 static int 332 linux_i2cbb_read_byte(void *cookie, uint8_t *bytep, int flags) 333 { 334 335 return i2c_bitbang_read_byte(cookie, bytep, flags, &linux_i2cbb_ops); 336 } 337 338 static int 339 linux_i2cbb_write_byte(void *cookie, uint8_t byte, int flags) 340 { 341 342 return i2c_bitbang_write_byte(cookie, byte, flags, &linux_i2cbb_ops); 343 } 344
Indexes created Tue Sep 30 20:09:53 GMT 2025