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 /* 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 { 130 131 return (*adapter->algo->master_xfer)(adapter, msgs, n); 132 } 133 134 int 135 i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 136 { 137 int ret; 138 139 if (adapter->lock_ops) 140 (*adapter->lock_ops->lock_bus)(adapter, 0); 141 ret = __i2c_transfer(adapter, msgs, n); 142 if (adapter->lock_ops) 143 (*adapter->lock_ops->unlock_bus)(adapter, 0); 144 145 return ret; 146 } 147 148 static int 149 netbsd_i2c_transfer(i2c_tag_t i2c, struct i2c_msg *msgs, int n) 150 { 151 int i; 152 int error; 153 154 for (i = 0; i < n; i++) { 155 const i2c_op_t op = linux_i2c_flags_op(msgs[i].flags, 156 ((i + 1) == n)); 157 const int flags = linux_i2c_flags_flags(msgs[i].flags); 158 159 switch (op) { 160 case I2C_OP_READ: 161 case I2C_OP_READ_WITH_STOP: 162 error = iic_exec(i2c, op, msgs[i].addr, 163 NULL, 0, msgs[i].buf, msgs[i].len, flags); 164 break; 165 166 case I2C_OP_WRITE: 167 case I2C_OP_WRITE_WITH_STOP: 168 error = iic_exec(i2c, op, msgs[i].addr, 169 msgs[i].buf, msgs[i].len, NULL, 0, flags); 170 break; 171 172 default: 173 error = EINVAL; 174 } 175 176 if (error) 177 /* XXX errno NetBSD->Linux */ 178 return -error; 179 } 180 181 return n; 182 } 183 184 static i2c_op_t 185 linux_i2c_flags_op(uint16_t flags, bool stop) 186 { 187 188 if (ISSET(flags, I2C_M_STOP)) 189 stop = true; 190 191 if (ISSET(flags, I2C_M_RD)) 192 return (stop? I2C_OP_READ_WITH_STOP : I2C_OP_READ); 193 else 194 return (stop? I2C_OP_WRITE_WITH_STOP : I2C_OP_WRITE); 195 } 196 197 static int 198 linux_i2c_flags_flags(uint16_t flags __unused) 199 { 200 201 return 0; 202 } 203 204 /* Bit-banging */ 205 206 const struct i2c_algorithm i2c_bit_algo = { 207 .master_xfer = linux_i2cbb_xfer, 208 .functionality = linux_i2cbb_functionality, 209 }; 210 211 static uint32_t 212 linux_i2cbb_functionality(struct i2c_adapter *adapter __unused) 213 { 214 uint32_t functions = 0; 215 216 functions |= I2C_FUNC_I2C; 217 functions |= I2C_FUNC_NOSTART; 218 functions |= I2C_FUNC_SMBUS_EMUL; 219 functions |= I2C_FUNC_SMBUS_READ_BLOCK_DATA; 220 functions |= I2C_FUNC_SMBUS_BLOCK_PROC_CALL; 221 #if 0 222 functions |= I2C_FUNC_10BIT_ADDR; 223 functions |= I2C_FUNC_PROTOCOL_MANGLING; 224 #endif 225 226 return functions; 227 } 228 229 static int 230 linux_i2cbb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 231 { 232 struct i2c_algo_bit_data *const abd = adapter->algo_data; 233 struct i2c_controller controller = { 234 .ic_cookie = abd, 235 .ic_send_start = linux_i2cbb_send_start, 236 .ic_send_stop = linux_i2cbb_send_stop, 237 .ic_initiate_xfer = linux_i2cbb_initiate_xfer, 238 .ic_read_byte = linux_i2cbb_read_byte, 239 .ic_write_byte = linux_i2cbb_write_byte, 240 }; 241 i2c_tag_t i2c = &controller; 242 int error; 243 244 if (abd->pre_xfer) { 245 error = (*abd->pre_xfer)(adapter); 246 if (error) 247 return error; 248 } 249 250 error = netbsd_i2c_transfer(i2c, msgs, n); 251 252 if (abd->post_xfer) 253 (*abd->post_xfer)(adapter); 254 255 return error; 256 } 257 258 #define LI2CBB_SDA 0x01 259 #define LI2CBB_SCL 0x02 260 #define LI2CBB_INPUT 0x04 261 #define LI2CBB_OUTPUT 0x08 262 263 static struct i2c_bitbang_ops linux_i2cbb_ops = { 264 .ibo_set_bits = linux_i2cbb_set_bits, 265 .ibo_set_dir = linux_i2cbb_set_dir, 266 .ibo_read_bits = linux_i2cbb_read_bits, 267 .ibo_bits = { 268 [I2C_BIT_SDA] = LI2CBB_SDA, 269 [I2C_BIT_SCL] = LI2CBB_SCL, 270 [I2C_BIT_INPUT] = LI2CBB_INPUT, 271 [I2C_BIT_OUTPUT] = LI2CBB_OUTPUT, 272 }, 273 }; 274 275 static void 276 linux_i2cbb_set_bits(void *cookie, uint32_t bits) 277 { 278 struct i2c_algo_bit_data *const abd = cookie; 279 280 (*abd->setsda)(abd->data, (ISSET(bits, LI2CBB_SDA)? 1 : 0)); 281 (*abd->setscl)(abd->data, (ISSET(bits, LI2CBB_SCL)? 1 : 0)); 282 } 283 284 static uint32_t 285 linux_i2cbb_read_bits(void *cookie) 286 { 287 struct i2c_algo_bit_data *const abd = cookie; 288 uint32_t bits = 0; 289 290 if ((*abd->getsda)(abd->data)) 291 bits |= LI2CBB_SDA; 292 if ((*abd->getscl)(abd->data)) 293 bits |= LI2CBB_SCL; 294 295 return bits; 296 } 297 298 static void 299 linux_i2cbb_set_dir(void *cookie __unused, uint32_t bits __unused) 300 { 301 /* Linux doesn't do anything here... */ 302 } 303 304 static int 305 linux_i2cbb_send_start(void *cookie, int flags) 306 { 307 308 return i2c_bitbang_send_start(cookie, flags, &linux_i2cbb_ops); 309 } 310 311 static int 312 linux_i2cbb_send_stop(void *cookie, int flags) 313 { 314 315 return i2c_bitbang_send_stop(cookie, flags, &linux_i2cbb_ops); 316 } 317 318 static int 319 linux_i2cbb_initiate_xfer(void *cookie, i2c_addr_t addr, int flags) 320 { 321 322 return i2c_bitbang_initiate_xfer(cookie, addr, flags, 323 &linux_i2cbb_ops); 324 } 325 326 static int 327 linux_i2cbb_read_byte(void *cookie, uint8_t *bytep, int flags) 328 { 329 330 return i2c_bitbang_read_byte(cookie, bytep, flags, &linux_i2cbb_ops); 331 } 332 333 static int 334 linux_i2cbb_write_byte(void *cookie, uint8_t byte, int flags) 335 { 336 337 return i2c_bitbang_write_byte(cookie, byte, flags, &linux_i2cbb_ops); 338 } 339