1 /* 2 * I2C multiplexer 3 * 4 * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> 5 * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> 6 * 7 * This module supports the PCA954x and PCA954x series of I2C multiplexer/switch 8 * chips made by NXP Semiconductors. 9 * This includes the: 10 * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547, 11 * PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849. 12 * 13 * These chips are all controlled via the I2C bus itself, and all have a 14 * single 8-bit register. The upstream "parent" bus fans out to two, 15 * four, or eight downstream busses or channels; which of these 16 * are selected is determined by the chip type and register contents. A 17 * mux can select only one sub-bus at a time; a switch can select any 18 * combination simultaneously. 19 * 20 * Based on: 21 * pca954x.c from Kumar Gala <galak@kernel.crashing.org> 22 * Copyright (C) 2006 23 * 24 * Based on: 25 * pca954x.c from Ken Harrenstien 26 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) 27 * 28 * Based on: 29 * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> 30 * and 31 * pca9540.c from Jean Delvare <jdelvare@suse.de>. 32 * 33 * This file is licensed under the terms of the GNU General Public 34 * License version 2. This program is licensed "as is" without any 35 * warranty of any kind, whether express or implied. 36 */ 37 38 #include <linux/device.h> 39 #include <linux/delay.h> 40 #include <linux/gpio/consumer.h> 41 #include <linux/i2c.h> 42 #include <linux/i2c-mux.h> 43 #include <linux/interrupt.h> 44 #include <linux/irq.h> 45 #include <linux/module.h> 46 #include <linux/of.h> 47 #include <linux/of_device.h> 48 #include <linux/of_irq.h> 49 #include <linux/platform_data/pca954x.h> 50 #include <linux/pm.h> 51 #include <linux/slab.h> 52 #include <linux/spinlock.h> 53 54 #define PCA954X_MAX_NCHANS 8 55 56 #define PCA954X_IRQ_OFFSET 4 57 58 enum pca_type { 59 pca_9540, 60 pca_9542, 61 pca_9543, 62 pca_9544, 63 pca_9545, 64 pca_9546, 65 pca_9547, 66 pca_9548, 67 pca_9846, 68 pca_9847, 69 pca_9848, 70 pca_9849, 71 }; 72 73 struct chip_desc { 74 u8 nchans; 75 u8 enable; /* used for muxes only */ 76 u8 has_irq; 77 enum muxtype { 78 pca954x_ismux = 0, 79 pca954x_isswi 80 } muxtype; 81 struct i2c_device_identity id; 82 }; 83 84 struct pca954x { 85 const struct chip_desc *chip; 86 87 u8 last_chan; /* last register value */ 88 u8 deselect; 89 struct i2c_client *client; 90 91 struct irq_domain *irq; 92 unsigned int irq_mask; 93 raw_spinlock_t lock; 94 }; 95 96 /* Provide specs for the PCA954x types we know about */ 97 static const struct chip_desc chips[] = { 98 [pca_9540] = { 99 .nchans = 2, 100 .enable = 0x4, 101 .muxtype = pca954x_ismux, 102 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 103 }, 104 [pca_9542] = { 105 .nchans = 2, 106 .enable = 0x4, 107 .has_irq = 1, 108 .muxtype = pca954x_ismux, 109 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 110 }, 111 [pca_9543] = { 112 .nchans = 2, 113 .has_irq = 1, 114 .muxtype = pca954x_isswi, 115 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 116 }, 117 [pca_9544] = { 118 .nchans = 4, 119 .enable = 0x4, 120 .has_irq = 1, 121 .muxtype = pca954x_ismux, 122 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 123 }, 124 [pca_9545] = { 125 .nchans = 4, 126 .has_irq = 1, 127 .muxtype = pca954x_isswi, 128 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 129 }, 130 [pca_9546] = { 131 .nchans = 4, 132 .muxtype = pca954x_isswi, 133 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 134 }, 135 [pca_9547] = { 136 .nchans = 8, 137 .enable = 0x8, 138 .muxtype = pca954x_ismux, 139 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 140 }, 141 [pca_9548] = { 142 .nchans = 8, 143 .muxtype = pca954x_isswi, 144 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 145 }, 146 [pca_9846] = { 147 .nchans = 4, 148 .muxtype = pca954x_isswi, 149 .id = { 150 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 151 .part_id = 0x10b, 152 }, 153 }, 154 [pca_9847] = { 155 .nchans = 8, 156 .enable = 0x8, 157 .muxtype = pca954x_ismux, 158 .id = { 159 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 160 .part_id = 0x108, 161 }, 162 }, 163 [pca_9848] = { 164 .nchans = 8, 165 .muxtype = pca954x_isswi, 166 .id = { 167 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 168 .part_id = 0x10a, 169 }, 170 }, 171 [pca_9849] = { 172 .nchans = 4, 173 .enable = 0x4, 174 .muxtype = pca954x_ismux, 175 .id = { 176 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 177 .part_id = 0x109, 178 }, 179 }, 180 }; 181 182 static const struct i2c_device_id pca954x_id[] = { 183 { "pca9540", pca_9540 }, 184 { "pca9542", pca_9542 }, 185 { "pca9543", pca_9543 }, 186 { "pca9544", pca_9544 }, 187 { "pca9545", pca_9545 }, 188 { "pca9546", pca_9546 }, 189 { "pca9547", pca_9547 }, 190 { "pca9548", pca_9548 }, 191 { "pca9846", pca_9846 }, 192 { "pca9847", pca_9847 }, 193 { "pca9848", pca_9848 }, 194 { "pca9849", pca_9849 }, 195 { } 196 }; 197 MODULE_DEVICE_TABLE(i2c, pca954x_id); 198 199 #ifdef CONFIG_OF 200 static const struct of_device_id pca954x_of_match[] = { 201 { .compatible = "nxp,pca9540", .data = &chips[pca_9540] }, 202 { .compatible = "nxp,pca9542", .data = &chips[pca_9542] }, 203 { .compatible = "nxp,pca9543", .data = &chips[pca_9543] }, 204 { .compatible = "nxp,pca9544", .data = &chips[pca_9544] }, 205 { .compatible = "nxp,pca9545", .data = &chips[pca_9545] }, 206 { .compatible = "nxp,pca9546", .data = &chips[pca_9546] }, 207 { .compatible = "nxp,pca9547", .data = &chips[pca_9547] }, 208 { .compatible = "nxp,pca9548", .data = &chips[pca_9548] }, 209 { .compatible = "nxp,pca9846", .data = &chips[pca_9846] }, 210 { .compatible = "nxp,pca9847", .data = &chips[pca_9847] }, 211 { .compatible = "nxp,pca9848", .data = &chips[pca_9848] }, 212 { .compatible = "nxp,pca9849", .data = &chips[pca_9849] }, 213 {} 214 }; 215 MODULE_DEVICE_TABLE(of, pca954x_of_match); 216 #endif 217 218 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() 219 for this as they will try to lock adapter a second time */ 220 static int pca954x_reg_write(struct i2c_adapter *adap, 221 struct i2c_client *client, u8 val) 222 { 223 union i2c_smbus_data dummy; 224 225 return __i2c_smbus_xfer(adap, client->addr, client->flags, 226 I2C_SMBUS_WRITE, val, 227 I2C_SMBUS_BYTE, &dummy); 228 } 229 230 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) 231 { 232 struct pca954x *data = i2c_mux_priv(muxc); 233 struct i2c_client *client = data->client; 234 const struct chip_desc *chip = data->chip; 235 u8 regval; 236 int ret = 0; 237 238 /* we make switches look like muxes, not sure how to be smarter */ 239 if (chip->muxtype == pca954x_ismux) 240 regval = chan | chip->enable; 241 else 242 regval = 1 << chan; 243 244 /* Only select the channel if its different from the last channel */ 245 if (data->last_chan != regval) { 246 ret = pca954x_reg_write(muxc->parent, client, regval); 247 data->last_chan = ret < 0 ? 0 : regval; 248 } 249 250 return ret; 251 } 252 253 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) 254 { 255 struct pca954x *data = i2c_mux_priv(muxc); 256 struct i2c_client *client = data->client; 257 258 if (!(data->deselect & (1 << chan))) 259 return 0; 260 261 /* Deselect active channel */ 262 data->last_chan = 0; 263 return pca954x_reg_write(muxc->parent, client, data->last_chan); 264 } 265 266 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) 267 { 268 struct pca954x *data = dev_id; 269 unsigned int child_irq; 270 int ret, i, handled = 0; 271 272 ret = i2c_smbus_read_byte(data->client); 273 if (ret < 0) 274 return IRQ_NONE; 275 276 for (i = 0; i < data->chip->nchans; i++) { 277 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) { 278 child_irq = irq_linear_revmap(data->irq, i); 279 handle_nested_irq(child_irq); 280 handled++; 281 } 282 } 283 return handled ? IRQ_HANDLED : IRQ_NONE; 284 } 285 286 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type) 287 { 288 if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW) 289 return -EINVAL; 290 return 0; 291 } 292 293 static struct irq_chip pca954x_irq_chip = { 294 .name = "i2c-mux-pca954x", 295 .irq_set_type = pca954x_irq_set_type, 296 }; 297 298 static int pca954x_irq_setup(struct i2c_mux_core *muxc) 299 { 300 struct pca954x *data = i2c_mux_priv(muxc); 301 struct i2c_client *client = data->client; 302 int c, irq; 303 304 if (!data->chip->has_irq || client->irq <= 0) 305 return 0; 306 307 raw_spin_lock_init(&data->lock); 308 309 data->irq = irq_domain_add_linear(client->dev.of_node, 310 data->chip->nchans, 311 &irq_domain_simple_ops, data); 312 if (!data->irq) 313 return -ENODEV; 314 315 for (c = 0; c < data->chip->nchans; c++) { 316 irq = irq_create_mapping(data->irq, c); 317 if (!irq) { 318 dev_err(&client->dev, "failed irq create map\n"); 319 return -EINVAL; 320 } 321 irq_set_chip_data(irq, data); 322 irq_set_chip_and_handler(irq, &pca954x_irq_chip, 323 handle_simple_irq); 324 } 325 326 return 0; 327 } 328 329 static void pca954x_cleanup(struct i2c_mux_core *muxc) 330 { 331 struct pca954x *data = i2c_mux_priv(muxc); 332 int c, irq; 333 334 if (data->irq) { 335 for (c = 0; c < data->chip->nchans; c++) { 336 irq = irq_find_mapping(data->irq, c); 337 irq_dispose_mapping(irq); 338 } 339 irq_domain_remove(data->irq); 340 } 341 i2c_mux_del_adapters(muxc); 342 } 343 344 /* 345 * I2C init/probing/exit functions 346 */ 347 static int pca954x_probe(struct i2c_client *client, 348 const struct i2c_device_id *id) 349 { 350 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); 351 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev); 352 struct device *dev = &client->dev; 353 struct device_node *np = dev->of_node; 354 bool idle_disconnect_dt; 355 struct gpio_desc *gpio; 356 int num, force, class; 357 struct i2c_mux_core *muxc; 358 struct pca954x *data; 359 int ret; 360 361 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) 362 return -ENODEV; 363 364 muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0, 365 pca954x_select_chan, pca954x_deselect_mux); 366 if (!muxc) 367 return -ENOMEM; 368 data = i2c_mux_priv(muxc); 369 370 i2c_set_clientdata(client, muxc); 371 data->client = client; 372 373 /* Reset the mux if a reset GPIO is specified. */ 374 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 375 if (IS_ERR(gpio)) 376 return PTR_ERR(gpio); 377 if (gpio) { 378 udelay(1); 379 gpiod_set_value_cansleep(gpio, 0); 380 /* Give the chip some time to recover. */ 381 udelay(1); 382 } 383 384 data->chip = of_device_get_match_data(dev); 385 if (!data->chip) 386 data->chip = &chips[id->driver_data]; 387 388 if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) { 389 struct i2c_device_identity id; 390 391 ret = i2c_get_device_id(client, &id); 392 if (ret && ret != -EOPNOTSUPP) 393 return ret; 394 395 if (!ret && 396 (id.manufacturer_id != data->chip->id.manufacturer_id || 397 id.part_id != data->chip->id.part_id)) { 398 dev_warn(dev, "unexpected device id %03x-%03x-%x\n", 399 id.manufacturer_id, id.part_id, 400 id.die_revision); 401 return -ENODEV; 402 } 403 } 404 405 /* Write the mux register at addr to verify 406 * that the mux is in fact present. This also 407 * initializes the mux to disconnected state. 408 */ 409 if (i2c_smbus_write_byte(client, 0) < 0) { 410 dev_warn(dev, "probe failed\n"); 411 return -ENODEV; 412 } 413 414 data->last_chan = 0; /* force the first selection */ 415 416 idle_disconnect_dt = np && 417 of_property_read_bool(np, "i2c-mux-idle-disconnect"); 418 419 ret = pca954x_irq_setup(muxc); 420 if (ret) 421 goto fail_cleanup; 422 423 /* Now create an adapter for each channel */ 424 for (num = 0; num < data->chip->nchans; num++) { 425 bool idle_disconnect_pd = false; 426 427 force = 0; /* dynamic adap number */ 428 class = 0; /* no class by default */ 429 if (pdata) { 430 if (num < pdata->num_modes) { 431 /* force static number */ 432 force = pdata->modes[num].adap_id; 433 class = pdata->modes[num].class; 434 } else 435 /* discard unconfigured channels */ 436 break; 437 idle_disconnect_pd = pdata->modes[num].deselect_on_exit; 438 } 439 data->deselect |= (idle_disconnect_pd || 440 idle_disconnect_dt) << num; 441 442 ret = i2c_mux_add_adapter(muxc, force, num, class); 443 if (ret) 444 goto fail_cleanup; 445 } 446 447 if (data->irq) { 448 ret = devm_request_threaded_irq(dev, data->client->irq, 449 NULL, pca954x_irq_handler, 450 IRQF_ONESHOT | IRQF_SHARED, 451 "pca954x", data); 452 if (ret) 453 goto fail_cleanup; 454 } 455 456 dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n", 457 num, data->chip->muxtype == pca954x_ismux 458 ? "mux" : "switch", client->name); 459 460 return 0; 461 462 fail_cleanup: 463 pca954x_cleanup(muxc); 464 return ret; 465 } 466 467 static int pca954x_remove(struct i2c_client *client) 468 { 469 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 470 471 pca954x_cleanup(muxc); 472 return 0; 473 } 474 475 #ifdef CONFIG_PM_SLEEP 476 static int pca954x_resume(struct device *dev) 477 { 478 struct i2c_client *client = to_i2c_client(dev); 479 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 480 struct pca954x *data = i2c_mux_priv(muxc); 481 482 data->last_chan = 0; 483 return i2c_smbus_write_byte(client, 0); 484 } 485 #endif 486 487 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); 488 489 static struct i2c_driver pca954x_driver = { 490 .driver = { 491 .name = "pca954x", 492 .pm = &pca954x_pm, 493 .of_match_table = of_match_ptr(pca954x_of_match), 494 }, 495 .probe = pca954x_probe, 496 .remove = pca954x_remove, 497 .id_table = pca954x_id, 498 }; 499 500 module_i2c_driver(pca954x_driver); 501 502 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); 503 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); 504 MODULE_LICENSE("GPL v2"); 505