linux_i2c.c revision 1.4
1/* $NetBSD: linux_i2c.c,v 1.4 2021/12/19 00:59:25 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 1.4 2021/12/19 00:59:25 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 46static int netbsd_i2c_transfer(i2c_tag_t, struct i2c_msg *, int); 47static i2c_op_t linux_i2c_flags_op(uint16_t, bool); 48static int linux_i2c_flags_flags(uint16_t); 49static uint32_t linux_i2cbb_functionality(struct i2c_adapter *); 50static int linux_i2cbb_xfer(struct i2c_adapter *, struct i2c_msg *, int); 51static void linux_i2cbb_set_bits(void *, uint32_t); 52static uint32_t linux_i2cbb_read_bits(void *); 53static void linux_i2cbb_set_dir(void *, uint32_t); 54static int linux_i2cbb_send_start(void *, int); 55static int linux_i2cbb_send_stop(void *, int); 56static int linux_i2cbb_initiate_xfer(void *, i2c_addr_t, int); 57static int linux_i2cbb_read_byte(void *, uint8_t *, int); 58static int linux_i2cbb_write_byte(void *, uint8_t, int); 59 60/* 61 * Client operations: operations with a particular i2c slave device. 62 */ 63 64struct i2c_client * 65i2c_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 77void 78i2c_unregister_device(struct i2c_client *client) 79{ 80 81 kmem_free(client, sizeof(*client)); 82} 83 84int 85i2c_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 104int 105i2c_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 127int 128i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 129{ 130 int ret; 131 132 if (adapter->lock_ops) 133 (*adapter->lock_ops->lock_bus)(adapter, 0); 134 ret = (*adapter->algo->master_xfer)(adapter, msgs, n); 135 if (adapter->lock_ops) 136 (*adapter->lock_ops->unlock_bus)(adapter, 0); 137 138 return ret; 139} 140 141static int 142netbsd_i2c_transfer(i2c_tag_t i2c, struct i2c_msg *msgs, int n) 143{ 144 int i; 145 int error; 146 147 for (i = 0; i < n; i++) { 148 const i2c_op_t op = linux_i2c_flags_op(msgs[i].flags, 149 ((i + 1) == n)); 150 const int flags = linux_i2c_flags_flags(msgs[i].flags); 151 152 switch (op) { 153 case I2C_OP_READ: 154 case I2C_OP_READ_WITH_STOP: 155 error = iic_exec(i2c, op, msgs[i].addr, 156 NULL, 0, msgs[i].buf, msgs[i].len, flags); 157 break; 158 159 case I2C_OP_WRITE: 160 case I2C_OP_WRITE_WITH_STOP: 161 error = iic_exec(i2c, op, msgs[i].addr, 162 msgs[i].buf, msgs[i].len, NULL, 0, flags); 163 break; 164 165 default: 166 error = EINVAL; 167 } 168 169 if (error) 170 /* XXX errno NetBSD->Linux */ 171 return -error; 172 } 173 174 return n; 175} 176 177static i2c_op_t 178linux_i2c_flags_op(uint16_t flags, bool stop) 179{ 180 181 if (ISSET(flags, I2C_M_RD)) 182 return (stop? I2C_OP_READ_WITH_STOP : I2C_OP_READ); 183 else 184 return (stop? I2C_OP_WRITE_WITH_STOP : I2C_OP_WRITE); 185} 186 187static int 188linux_i2c_flags_flags(uint16_t flags __unused) 189{ 190 191 return 0; 192} 193 194/* Bit-banging */ 195 196const struct i2c_algorithm i2c_bit_algo = { 197 .master_xfer = linux_i2cbb_xfer, 198 .functionality = linux_i2cbb_functionality, 199}; 200 201static uint32_t 202linux_i2cbb_functionality(struct i2c_adapter *adapter __unused) 203{ 204 uint32_t functions = 0; 205 206 functions |= I2C_FUNC_I2C; 207 functions |= I2C_FUNC_NOSTART; 208 functions |= I2C_FUNC_SMBUS_EMUL; 209 functions |= I2C_FUNC_SMBUS_READ_BLOCK_DATA; 210 functions |= I2C_FUNC_SMBUS_BLOCK_PROC_CALL; 211#if 0 212 functions |= I2C_FUNC_10BIT_ADDR; 213 functions |= I2C_FUNC_PROTOCOL_MANGLING; 214#endif 215 216 return functions; 217} 218 219static int 220linux_i2cbb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int n) 221{ 222 struct i2c_algo_bit_data *const abd = adapter->algo_data; 223 struct i2c_controller controller = { 224 .ic_cookie = abd, 225 .ic_send_start = linux_i2cbb_send_start, 226 .ic_send_stop = linux_i2cbb_send_stop, 227 .ic_initiate_xfer = linux_i2cbb_initiate_xfer, 228 .ic_read_byte = linux_i2cbb_read_byte, 229 .ic_write_byte = linux_i2cbb_write_byte, 230 }; 231 i2c_tag_t i2c = &controller; 232 int error; 233 234 if (abd->pre_xfer) { 235 error = (*abd->pre_xfer)(adapter); 236 if (error) 237 return error; 238 } 239 240 error = netbsd_i2c_transfer(i2c, msgs, n); 241 242 if (abd->post_xfer) 243 (*abd->post_xfer)(adapter); 244 245 return error; 246} 247 248#define LI2CBB_SDA 0x01 249#define LI2CBB_SCL 0x02 250#define LI2CBB_INPUT 0x04 251#define LI2CBB_OUTPUT 0x08 252 253static struct i2c_bitbang_ops linux_i2cbb_ops = { 254 .ibo_set_bits = linux_i2cbb_set_bits, 255 .ibo_set_dir = linux_i2cbb_set_dir, 256 .ibo_read_bits = linux_i2cbb_read_bits, 257 .ibo_bits = { 258 [I2C_BIT_SDA] = LI2CBB_SDA, 259 [I2C_BIT_SCL] = LI2CBB_SCL, 260 [I2C_BIT_INPUT] = LI2CBB_INPUT, 261 [I2C_BIT_OUTPUT] = LI2CBB_OUTPUT, 262 }, 263}; 264 265static void 266linux_i2cbb_set_bits(void *cookie, uint32_t bits) 267{ 268 struct i2c_algo_bit_data *const abd = cookie; 269 270 (*abd->setsda)(abd->data, (ISSET(bits, LI2CBB_SDA)? 1 : 0)); 271 (*abd->setscl)(abd->data, (ISSET(bits, LI2CBB_SCL)? 1 : 0)); 272} 273 274static uint32_t 275linux_i2cbb_read_bits(void *cookie) 276{ 277 struct i2c_algo_bit_data *const abd = cookie; 278 uint32_t bits = 0; 279 280 if ((*abd->getsda)(abd->data)) 281 bits |= LI2CBB_SDA; 282 if ((*abd->getscl)(abd->data)) 283 bits |= LI2CBB_SCL; 284 285 return bits; 286} 287 288static void 289linux_i2cbb_set_dir(void *cookie __unused, uint32_t bits __unused) 290{ 291 /* Linux doesn't do anything here... */ 292} 293 294static int 295linux_i2cbb_send_start(void *cookie, int flags) 296{ 297 298 return i2c_bitbang_send_start(cookie, flags, &linux_i2cbb_ops); 299} 300 301static int 302linux_i2cbb_send_stop(void *cookie, int flags) 303{ 304 305 return i2c_bitbang_send_stop(cookie, flags, &linux_i2cbb_ops); 306} 307 308static int 309linux_i2cbb_initiate_xfer(void *cookie, i2c_addr_t addr, int flags) 310{ 311 312 return i2c_bitbang_initiate_xfer(cookie, addr, flags, 313 &linux_i2cbb_ops); 314} 315 316static int 317linux_i2cbb_read_byte(void *cookie, uint8_t *bytep, int flags) 318{ 319 320 return i2c_bitbang_read_byte(cookie, bytep, flags, &linux_i2cbb_ops); 321} 322 323static int 324linux_i2cbb_write_byte(void *cookie, uint8_t byte, int flags) 325{ 326 327 return i2c_bitbang_write_byte(cookie, byte, flags, &linux_i2cbb_ops); 328} 329