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 * 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 78 i2c_unregister_device(struct i2c_client *client) 79 { 80 81 kmem_free(client, sizeof(*client)); 82 } 83 84 int 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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