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 series of I2C multiplexer/switch chips 8 * made by Philips Semiconductors. 9 * This includes the: 10 * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547 11 * and PCA9548. 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/acpi.h> 39 #include <linux/device.h> 40 #include <linux/gpio/consumer.h> 41 #include <linux/i2c.h> 42 #include <linux/i2c-mux.h> 43 #include <linux/i2c/pca954x.h> 44 #include <linux/interrupt.h> 45 #include <linux/irq.h> 46 #include <linux/module.h> 47 #include <linux/of.h> 48 #include <linux/of_device.h> 49 #include <linux/of_irq.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 }; 68 69 struct chip_desc { 70 u8 nchans; 71 u8 enable; /* used for muxes only */ 72 u8 has_irq; 73 enum muxtype { 74 pca954x_ismux = 0, 75 pca954x_isswi 76 } muxtype; 77 }; 78 79 struct pca954x { 80 const struct chip_desc *chip; 81 82 u8 last_chan; /* last register value */ 83 u8 deselect; 84 struct i2c_client *client; 85 86 struct irq_domain *irq; 87 unsigned int irq_mask; 88 spinlock_t lock; 89 }; 90 91 /* Provide specs for the PCA954x types we know about */ 92 static const struct chip_desc chips[] = { 93 [pca_9540] = { 94 .nchans = 2, 95 .enable = 0x4, 96 .muxtype = pca954x_ismux, 97 }, 98 [pca_9542] = { 99 .nchans = 2, 100 .enable = 0x4, 101 .has_irq = 1, 102 .muxtype = pca954x_ismux, 103 }, 104 [pca_9543] = { 105 .nchans = 2, 106 .has_irq = 1, 107 .muxtype = pca954x_isswi, 108 }, 109 [pca_9544] = { 110 .nchans = 4, 111 .enable = 0x4, 112 .has_irq = 1, 113 .muxtype = pca954x_ismux, 114 }, 115 [pca_9545] = { 116 .nchans = 4, 117 .has_irq = 1, 118 .muxtype = pca954x_isswi, 119 }, 120 [pca_9547] = { 121 .nchans = 8, 122 .enable = 0x8, 123 .muxtype = pca954x_ismux, 124 }, 125 [pca_9548] = { 126 .nchans = 8, 127 .muxtype = pca954x_isswi, 128 }, 129 }; 130 131 static const struct i2c_device_id pca954x_id[] = { 132 { "pca9540", pca_9540 }, 133 { "pca9542", pca_9542 }, 134 { "pca9543", pca_9543 }, 135 { "pca9544", pca_9544 }, 136 { "pca9545", pca_9545 }, 137 { "pca9546", pca_9545 }, 138 { "pca9547", pca_9547 }, 139 { "pca9548", pca_9548 }, 140 { } 141 }; 142 MODULE_DEVICE_TABLE(i2c, pca954x_id); 143 144 #ifdef CONFIG_ACPI 145 static const struct acpi_device_id pca954x_acpi_ids[] = { 146 { .id = "PCA9540", .driver_data = pca_9540 }, 147 { .id = "PCA9542", .driver_data = pca_9542 }, 148 { .id = "PCA9543", .driver_data = pca_9543 }, 149 { .id = "PCA9544", .driver_data = pca_9544 }, 150 { .id = "PCA9545", .driver_data = pca_9545 }, 151 { .id = "PCA9546", .driver_data = pca_9545 }, 152 { .id = "PCA9547", .driver_data = pca_9547 }, 153 { .id = "PCA9548", .driver_data = pca_9548 }, 154 { } 155 }; 156 MODULE_DEVICE_TABLE(acpi, pca954x_acpi_ids); 157 #endif 158 159 #ifdef CONFIG_OF 160 static const struct of_device_id pca954x_of_match[] = { 161 { .compatible = "nxp,pca9540", .data = &chips[pca_9540] }, 162 { .compatible = "nxp,pca9542", .data = &chips[pca_9542] }, 163 { .compatible = "nxp,pca9543", .data = &chips[pca_9543] }, 164 { .compatible = "nxp,pca9544", .data = &chips[pca_9544] }, 165 { .compatible = "nxp,pca9545", .data = &chips[pca_9545] }, 166 { .compatible = "nxp,pca9546", .data = &chips[pca_9546] }, 167 { .compatible = "nxp,pca9547", .data = &chips[pca_9547] }, 168 { .compatible = "nxp,pca9548", .data = &chips[pca_9548] }, 169 {} 170 }; 171 MODULE_DEVICE_TABLE(of, pca954x_of_match); 172 #endif 173 174 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() 175 for this as they will try to lock adapter a second time */ 176 static int pca954x_reg_write(struct i2c_adapter *adap, 177 struct i2c_client *client, u8 val) 178 { 179 int ret = -ENODEV; 180 181 if (adap->algo->master_xfer) { 182 struct i2c_msg msg; 183 char buf[1]; 184 185 msg.addr = client->addr; 186 msg.flags = 0; 187 msg.len = 1; 188 buf[0] = val; 189 msg.buf = buf; 190 ret = __i2c_transfer(adap, &msg, 1); 191 192 if (ret >= 0 && ret != 1) 193 ret = -EREMOTEIO; 194 } else { 195 union i2c_smbus_data data; 196 ret = adap->algo->smbus_xfer(adap, client->addr, 197 client->flags, 198 I2C_SMBUS_WRITE, 199 val, I2C_SMBUS_BYTE, &data); 200 } 201 202 return ret; 203 } 204 205 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) 206 { 207 struct pca954x *data = i2c_mux_priv(muxc); 208 struct i2c_client *client = data->client; 209 const struct chip_desc *chip = data->chip; 210 u8 regval; 211 int ret = 0; 212 213 /* we make switches look like muxes, not sure how to be smarter */ 214 if (chip->muxtype == pca954x_ismux) 215 regval = chan | chip->enable; 216 else 217 regval = 1 << chan; 218 219 /* Only select the channel if its different from the last channel */ 220 if (data->last_chan != regval) { 221 ret = pca954x_reg_write(muxc->parent, client, regval); 222 data->last_chan = ret < 0 ? 0 : regval; 223 } 224 225 return ret; 226 } 227 228 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) 229 { 230 struct pca954x *data = i2c_mux_priv(muxc); 231 struct i2c_client *client = data->client; 232 233 if (!(data->deselect & (1 << chan))) 234 return 0; 235 236 /* Deselect active channel */ 237 data->last_chan = 0; 238 return pca954x_reg_write(muxc->parent, client, data->last_chan); 239 } 240 241 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) 242 { 243 struct pca954x *data = dev_id; 244 unsigned int child_irq; 245 int ret, i, handled = 0; 246 247 ret = i2c_smbus_read_byte(data->client); 248 if (ret < 0) 249 return IRQ_NONE; 250 251 for (i = 0; i < data->chip->nchans; i++) { 252 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) { 253 child_irq = irq_linear_revmap(data->irq, i); 254 handle_nested_irq(child_irq); 255 handled++; 256 } 257 } 258 return handled ? IRQ_HANDLED : IRQ_NONE; 259 } 260 261 static void pca954x_irq_mask(struct irq_data *idata) 262 { 263 struct pca954x *data = irq_data_get_irq_chip_data(idata); 264 unsigned int pos = idata->hwirq; 265 unsigned long flags; 266 267 spin_lock_irqsave(&data->lock, flags); 268 269 data->irq_mask &= ~BIT(pos); 270 if (!data->irq_mask) 271 disable_irq(data->client->irq); 272 273 spin_unlock_irqrestore(&data->lock, flags); 274 } 275 276 static void pca954x_irq_unmask(struct irq_data *idata) 277 { 278 struct pca954x *data = irq_data_get_irq_chip_data(idata); 279 unsigned int pos = idata->hwirq; 280 unsigned long flags; 281 282 spin_lock_irqsave(&data->lock, flags); 283 284 if (!data->irq_mask) 285 enable_irq(data->client->irq); 286 data->irq_mask |= BIT(pos); 287 288 spin_unlock_irqrestore(&data->lock, flags); 289 } 290 291 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type) 292 { 293 if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW) 294 return -EINVAL; 295 return 0; 296 } 297 298 static struct irq_chip pca954x_irq_chip = { 299 .name = "i2c-mux-pca954x", 300 .irq_mask = pca954x_irq_mask, 301 .irq_unmask = pca954x_irq_unmask, 302 .irq_set_type = pca954x_irq_set_type, 303 }; 304 305 static int pca954x_irq_setup(struct i2c_mux_core *muxc) 306 { 307 struct pca954x *data = i2c_mux_priv(muxc); 308 struct i2c_client *client = data->client; 309 int c, err, irq; 310 311 if (!data->chip->has_irq || client->irq <= 0) 312 return 0; 313 314 spin_lock_init(&data->lock); 315 316 data->irq = irq_domain_add_linear(client->dev.of_node, 317 data->chip->nchans, 318 &irq_domain_simple_ops, data); 319 if (!data->irq) 320 return -ENODEV; 321 322 for (c = 0; c < data->chip->nchans; c++) { 323 irq = irq_create_mapping(data->irq, c); 324 irq_set_chip_data(irq, data); 325 irq_set_chip_and_handler(irq, &pca954x_irq_chip, 326 handle_simple_irq); 327 } 328 329 err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL, 330 pca954x_irq_handler, 331 IRQF_ONESHOT | IRQF_SHARED, 332 "pca954x", data); 333 if (err) 334 goto err_req_irq; 335 336 disable_irq(data->client->irq); 337 338 return 0; 339 err_req_irq: 340 for (c = 0; c < data->chip->nchans; c++) { 341 irq = irq_find_mapping(data->irq, c); 342 irq_dispose_mapping(irq); 343 } 344 irq_domain_remove(data->irq); 345 346 return err; 347 } 348 349 /* 350 * I2C init/probing/exit functions 351 */ 352 static int pca954x_probe(struct i2c_client *client, 353 const struct i2c_device_id *id) 354 { 355 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); 356 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev); 357 struct device_node *of_node = client->dev.of_node; 358 bool idle_disconnect_dt; 359 struct gpio_desc *gpio; 360 int num, force, class; 361 struct i2c_mux_core *muxc; 362 struct pca954x *data; 363 const struct of_device_id *match; 364 int ret; 365 366 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) 367 return -ENODEV; 368 369 muxc = i2c_mux_alloc(adap, &client->dev, 370 PCA954X_MAX_NCHANS, sizeof(*data), 0, 371 pca954x_select_chan, pca954x_deselect_mux); 372 if (!muxc) 373 return -ENOMEM; 374 data = i2c_mux_priv(muxc); 375 376 i2c_set_clientdata(client, muxc); 377 data->client = client; 378 379 /* Get the mux out of reset if a reset GPIO is specified. */ 380 gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW); 381 if (IS_ERR(gpio)) 382 return PTR_ERR(gpio); 383 384 /* Write the mux register at addr to verify 385 * that the mux is in fact present. This also 386 * initializes the mux to disconnected state. 387 */ 388 if (i2c_smbus_write_byte(client, 0) < 0) { 389 dev_warn(&client->dev, "probe failed\n"); 390 return -ENODEV; 391 } 392 393 match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev); 394 if (match) 395 data->chip = of_device_get_match_data(&client->dev); 396 else if (id) 397 data->chip = &chips[id->driver_data]; 398 else { 399 const struct acpi_device_id *acpi_id; 400 401 acpi_id = acpi_match_device(ACPI_PTR(pca954x_acpi_ids), 402 &client->dev); 403 if (!acpi_id) 404 return -ENODEV; 405 data->chip = &chips[acpi_id->driver_data]; 406 } 407 408 data->last_chan = 0; /* force the first selection */ 409 410 idle_disconnect_dt = of_node && 411 of_property_read_bool(of_node, "i2c-mux-idle-disconnect"); 412 413 ret = pca954x_irq_setup(muxc); 414 if (ret) 415 goto fail_del_adapters; 416 417 /* Now create an adapter for each channel */ 418 for (num = 0; num < data->chip->nchans; num++) { 419 bool idle_disconnect_pd = false; 420 421 force = 0; /* dynamic adap number */ 422 class = 0; /* no class by default */ 423 if (pdata) { 424 if (num < pdata->num_modes) { 425 /* force static number */ 426 force = pdata->modes[num].adap_id; 427 class = pdata->modes[num].class; 428 } else 429 /* discard unconfigured channels */ 430 break; 431 idle_disconnect_pd = pdata->modes[num].deselect_on_exit; 432 } 433 data->deselect |= (idle_disconnect_pd || 434 idle_disconnect_dt) << num; 435 436 ret = i2c_mux_add_adapter(muxc, force, num, class); 437 438 if (ret) { 439 dev_err(&client->dev, 440 "failed to register multiplexed adapter" 441 " %d as bus %d\n", num, force); 442 goto fail_del_adapters; 443 } 444 } 445 446 dev_info(&client->dev, 447 "registered %d multiplexed busses for I2C %s %s\n", 448 num, data->chip->muxtype == pca954x_ismux 449 ? "mux" : "switch", client->name); 450 451 return 0; 452 453 fail_del_adapters: 454 i2c_mux_del_adapters(muxc); 455 return ret; 456 } 457 458 static int pca954x_remove(struct i2c_client *client) 459 { 460 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 461 struct pca954x *data = i2c_mux_priv(muxc); 462 int c, irq; 463 464 if (data->irq) { 465 for (c = 0; c < data->chip->nchans; c++) { 466 irq = irq_find_mapping(data->irq, c); 467 irq_dispose_mapping(irq); 468 } 469 irq_domain_remove(data->irq); 470 } 471 472 i2c_mux_del_adapters(muxc); 473 return 0; 474 } 475 476 #ifdef CONFIG_PM_SLEEP 477 static int pca954x_resume(struct device *dev) 478 { 479 struct i2c_client *client = to_i2c_client(dev); 480 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 481 struct pca954x *data = i2c_mux_priv(muxc); 482 483 data->last_chan = 0; 484 return i2c_smbus_write_byte(client, 0); 485 } 486 #endif 487 488 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); 489 490 static struct i2c_driver pca954x_driver = { 491 .driver = { 492 .name = "pca954x", 493 .pm = &pca954x_pm, 494 .of_match_table = of_match_ptr(pca954x_of_match), 495 .acpi_match_table = ACPI_PTR(pca954x_acpi_ids), 496 }, 497 .probe = pca954x_probe, 498 .remove = pca954x_remove, 499 .id_table = pca954x_id, 500 }; 501 502 module_i2c_driver(pca954x_driver); 503 504 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); 505 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); 506 MODULE_LICENSE("GPL v2"); 507