drivers/pinctrl/pinmux.c

   1 /*
   2  * Core driver for the pin muxing portions of the pin control subsystem
   3  *
   4  * Copyright (C) 2011-2012 ST-Ericsson SA
   5  * Written on behalf of Linaro for ST-Ericsson
   6  * Based on bits of regulator core, gpio core and clk core
   7  *
   8  * Author: Linus Walleij <linus.walleij@linaro.org>
   9  *
  10  * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
  11  *
  12  * License terms: GNU General Public License (GPL) version 2
  13  */
  14 #define pr_fmt(fmt) "pinmux core: " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/device.h>
  20 #include <linux/slab.h>
  21 #include <linux/radix-tree.h>
  22 #include <linux/err.h>
  23 #include <linux/list.h>
  24 #include <linux/string.h>
  25 #include <linux/sysfs.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/pinctrl/machine.h>
  29 #include <linux/pinctrl/pinmux.h>
  30 #include "core.h"
  31 #include "pinmux.h"
  32
  33 int pinmux_check_ops(struct pinctrl_dev *pctldev)
  34 {
  35         const struct pinmux_ops *ops = pctldev->desc->pmxops;
  36         unsigned nfuncs;
  37         unsigned selector = 0;
  38
  39         /* Check that we implement required operations */
  40         if (!ops ||
  41             !ops->get_functions_count ||
  42             !ops->get_function_name ||
  43             !ops->get_function_groups ||
  44             !ops->enable ||
  45             !ops->disable)
  46                 return -EINVAL;
  47
  48         /* Check that all functions registered have names */
  49         nfuncs = ops->get_functions_count(pctldev);
  50         while (selector < nfuncs) {
  51                 const char *fname = ops->get_function_name(pctldev,
  52                                                            selector);
  53                 if (!fname) {
  54                         dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
  55                                 selector);
  56                         return -EINVAL;
  57                 }
  58                 selector++;
  59         }
  60
  61         return 0;
  62 }
  63
  64 int pinmux_validate_map(struct pinctrl_map const *map, int i)
  65 {
  66         if (!map->data.mux.function) {
  67                 pr_err("failed to register map %s (%d): no function given\n",
  68                        map->name, i);
  69                 return -EINVAL;
  70         }
  71
  72         return 0;
  73 }
  74
  75 /**
  76  * pin_request() - request a single pin to be muxed in, typically for GPIO
  77  * @pin: the pin number in the global pin space
  78  * @owner: a representation of the owner of this pin; typically the device
  79  *      name that controls its mux function, or the requested GPIO name
  80  * @gpio_range: the range matching the GPIO pin if this is a request for a
  81  *      single GPIO pin
  82  */
  83 static int pin_request(struct pinctrl_dev *pctldev,
  84                        int pin, const char *owner,
  85                        struct pinctrl_gpio_range *gpio_range)
  86 {
  87         struct pin_desc *desc;
  88         const struct pinmux_ops *ops = pctldev->desc->pmxops;
  89         int status = -EINVAL;
  90
  91         desc = pin_desc_get(pctldev, pin);
  92         if (desc == NULL) {
  93                 dev_err(pctldev->dev,
  94                         "pin is not registered so it cannot be requested\n");
  95                 goto out;
  96         }
  97
  98         dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
  99                 pin, desc->name, owner);
 100
 101         if (gpio_range) {
 102                 /* There's no need to support multiple GPIO requests */
 103                 if (desc->gpio_owner) {
 104                         dev_err(pctldev->dev,
 105                                 "pin already requested\n");
 106                         goto out;
 107                 }
 108
 109                 desc->gpio_owner = owner;
 110         } else {
 111                 if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
 112                         dev_err(pctldev->dev,
 113                                 "pin already requested\n");
 114                         goto out;
 115                 }
 116
 117                 desc->mux_usecount++;
 118                 if (desc->mux_usecount > 1)
 119                         return 0;
 120
 121                 desc->mux_owner = owner;
 122         }
 123
 124         /* Let each pin increase references to this module */
 125         if (!try_module_get(pctldev->owner)) {
 126                 dev_err(pctldev->dev,
 127                         "could not increase module refcount for pin %d\n",
 128                         pin);
 129                 status = -EINVAL;
 130                 goto out_free_pin;
 131         }
 132
 133         /*
 134          * If there is no kind of request function for the pin we just assume
 135          * we got it by default and proceed.
 136          */
 137         if (gpio_range && ops->gpio_request_enable)
 138                 /* This requests and enables a single GPIO pin */
 139                 status = ops->gpio_request_enable(pctldev, gpio_range, pin);
 140         else if (ops->request)
 141                 status = ops->request(pctldev, pin);
 142         else
 143                 status = 0;
 144
 145         if (status) {
 146                 dev_err(pctldev->dev, "->request on device %s failed for pin %d\n",
 147                        pctldev->desc->name, pin);
 148                 module_put(pctldev->owner);
 149         }
 150
 151 out_free_pin:
 152         if (status) {
 153                 if (gpio_range) {
 154                         desc->gpio_owner = NULL;
 155                 } else {
 156                         desc->mux_usecount--;
 157                         if (!desc->mux_usecount)
 158                                 desc->mux_owner = NULL;
 159                 }
 160         }
 161 out:
 162         if (status)
 163                 dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
 164                        pin, owner, status);
 165
 166         return status;
 167 }
 168
 169 /**
 170  * pin_free() - release a single muxed in pin so something else can be muxed
 171  * @pctldev: pin controller device handling this pin
 172  * @pin: the pin to free
 173  * @gpio_range: the range matching the GPIO pin if this is a request for a
 174  *      single GPIO pin
 175  *
 176  * This function returns a pointer to the previous owner. This is used
 177  * for callers that dynamically allocate an owner name so it can be freed
 178  * once the pin is free. This is done for GPIO request functions.
 179  */
 180 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 181                             struct pinctrl_gpio_range *gpio_range)
 182 {
 183         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 184         struct pin_desc *desc;
 185         const char *owner;
 186
 187         desc = pin_desc_get(pctldev, pin);
 188         if (desc == NULL) {
 189                 dev_err(pctldev->dev,
 190                         "pin is not registered so it cannot be freed\n");
 191                 return NULL;
 192         }
 193
 194         if (!gpio_range) {
 195                 desc->mux_usecount--;
 196                 if (desc->mux_usecount)
 197                         return NULL;
 198         }
 199
 200         /*
 201          * If there is no kind of request function for the pin we just assume
 202          * we got it by default and proceed.
 203          */
 204         if (gpio_range && ops->gpio_disable_free)
 205                 ops->gpio_disable_free(pctldev, gpio_range, pin);
 206         else if (ops->free)
 207                 ops->free(pctldev, pin);
 208
 209         if (gpio_range) {
 210                 owner = desc->gpio_owner;
 211                 desc->gpio_owner = NULL;
 212         } else {
 213                 owner = desc->mux_owner;
 214                 desc->mux_owner = NULL;
 215                 desc->mux_setting = NULL;
 216         }
 217
 218         module_put(pctldev->owner);
 219
 220         return owner;
 221 }
 222
 223 /**
 224  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 225  * @pctldev: pin controller device affected
 226  * @pin: the pin to mux in for GPIO
 227  * @range: the applicable GPIO range
 228  */
 229 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 230                         struct pinctrl_gpio_range *range,
 231                         unsigned pin, unsigned gpio)
 232 {
 233         char gpiostr[16];
 234         const char *owner;
 235         int ret;
 236
 237         /* Conjure some name stating what chip and pin this is taken by */
 238         snprintf(gpiostr, 15, "%s:%d", range->name, gpio);
 239
 240         owner = kstrdup(gpiostr, GFP_KERNEL);
 241         if (!owner)
 242                 return -EINVAL;
 243
 244         ret = pin_request(pctldev, pin, owner, range);
 245         if (ret < 0)
 246                 kfree(owner);
 247
 248         return ret;
 249 }
 250
 251 /**
 252  * pinmux_free_gpio() - release a pin from GPIO muxing
 253  * @pctldev: the pin controller device for the pin
 254  * @pin: the affected currently GPIO-muxed in pin
 255  * @range: applicable GPIO range
 256  */
 257 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 258                       struct pinctrl_gpio_range *range)
 259 {
 260         const char *owner;
 261
 262         owner = pin_free(pctldev, pin, range);
 263         kfree(owner);
 264 }
 265
 266 /**
 267  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 268  * @pctldev: the pin controller handling this pin
 269  * @range: applicable GPIO range
 270  * @pin: the affected GPIO pin in this controller
 271  * @input: true if we set the pin as input, false for output
 272  */
 273 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 274                           struct pinctrl_gpio_range *range,
 275                           unsigned pin, bool input)
 276 {
 277         const struct pinmux_ops *ops;
 278         int ret;
 279
 280         ops = pctldev->desc->pmxops;
 281
 282         if (ops->gpio_set_direction)
 283                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 284         else
 285                 ret = 0;
 286
 287         return ret;
 288 }
 289
 290 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 291                                         const char *function)
 292 {
 293         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 294         unsigned nfuncs = ops->get_functions_count(pctldev);
 295         unsigned selector = 0;
 296
 297         /* See if this pctldev has this function */
 298         while (selector < nfuncs) {
 299                 const char *fname = ops->get_function_name(pctldev,
 300                                                            selector);
 301
 302                 if (!strcmp(function, fname))
 303                         return selector;
 304
 305                 selector++;
 306         }
 307
 308         pr_err("%s does not support function %s\n",
 309                pinctrl_dev_get_name(pctldev), function);
 310         return -EINVAL;
 311 }
 312
 313 int pinmux_map_to_setting(struct pinctrl_map const *map,
 314                           struct pinctrl_setting *setting)
 315 {
 316         struct pinctrl_dev *pctldev = setting->pctldev;
 317         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 318         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 319         char const * const *groups;
 320         unsigned num_groups;
 321         int ret;
 322         const char *group;
 323         int i;
 324         const unsigned *pins;
 325         unsigned num_pins;
 326
 327         if (!pmxops) {
 328                 dev_err(pctldev->dev, "does not support mux function\n");
 329                 return -EINVAL;
 330         }
 331
 332         setting->data.mux.func =
 333                 pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 334         if (setting->data.mux.func < 0)
 335                 return setting->data.mux.func;
 336
 337         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 338                                           &groups, &num_groups);
 339         if (ret < 0)
 340                 return ret;
 341         if (!num_groups)
 342                 return -EINVAL;
 343
 344         if (map->data.mux.group) {
 345                 bool found = false;
 346                 group = map->data.mux.group;
 347                 for (i = 0; i < num_groups; i++) {
 348                         if (!strcmp(group, groups[i])) {
 349                                 found = true;
 350                                 break;
 351                         }
 352                 }
 353                 if (!found)
 354                         return -EINVAL;
 355         } else {
 356                 group = groups[0];
 357         }
 358
 359         setting->data.mux.group = pinctrl_get_group_selector(pctldev, group);
 360         if (setting->data.mux.group < 0)
 361                 return setting->data.mux.group;
 362
 363         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 364                                       &num_pins);
 365         if (ret) {
 366                 dev_err(pctldev->dev,
 367                         "could not get pins for device %s group selector %d\n",
 368                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 369                         return -ENODEV;
 370         }
 371
 372         /* Try to allocate all pins in this group, one by one */
 373         for (i = 0; i < num_pins; i++) {
 374                 ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
 375                 if (ret) {
 376                         dev_err(pctldev->dev,
 377                                 "could not get request pin %d on device %s\n",
 378                                 pins[i], pinctrl_dev_get_name(pctldev));
 379                         /* On error release all taken pins */
 380                         i--; /* this pin just failed */
 381                         for (; i >= 0; i--)
 382                                 pin_free(pctldev, pins[i], NULL);
 383                         return -ENODEV;
 384                 }
 385         }
 386
 387         return 0;
 388 }
 389
 390 void pinmux_free_setting(struct pinctrl_setting const *setting)
 391 {
 392         struct pinctrl_dev *pctldev = setting->pctldev;
 393         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 394         const unsigned *pins;
 395         unsigned num_pins;
 396         int ret;
 397         int i;
 398
 399         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 400                                       &pins, &num_pins);
 401         if (ret) {
 402                 dev_err(pctldev->dev,
 403                         "could not get pins for device %s group selector %d\n",
 404                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 405                 return;
 406         }
 407
 408         for (i = 0; i < num_pins; i++)
 409                 pin_free(pctldev, pins[i], NULL);
 410 }
 411
 412 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 413 {
 414         struct pinctrl_dev *pctldev = setting->pctldev;
 415         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 416         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 417         int ret;
 418         const unsigned *pins;
 419         unsigned num_pins;
 420         int i;
 421         struct pin_desc *desc;
 422
 423         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 424                                       &pins, &num_pins);
 425         if (ret) {
 426                 /* errors only affect debug data, so just warn */
 427                 dev_warn(pctldev->dev,
 428                          "could not get pins for group selector %d\n",
 429                          setting->data.mux.group);
 430                 num_pins = 0;
 431         }
 432
 433         for (i = 0; i < num_pins; i++) {
 434                 desc = pin_desc_get(pctldev, pins[i]);
 435                 if (desc == NULL) {
 436                         dev_warn(pctldev->dev,
 437                                  "could not get pin desc for pin %d\n",
 438                                  pins[i]);
 439                         continue;
 440                 }
 441                 desc->mux_setting = &(setting->data.mux);
 442         }
 443
 444         return ops->enable(pctldev, setting->data.mux.func,
 445                            setting->data.mux.group);
 446 }
 447
 448 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 449 {
 450         struct pinctrl_dev *pctldev = setting->pctldev;
 451         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 452         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 453         int ret;
 454         const unsigned *pins;
 455         unsigned num_pins;
 456         int i;
 457         struct pin_desc *desc;
 458
 459         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 460                                       &pins, &num_pins);
 461         if (ret) {
 462                 /* errors only affect debug data, so just warn */
 463                 dev_warn(pctldev->dev,
 464                          "could not get pins for group selector %d\n",
 465                          setting->data.mux.group);
 466                 num_pins = 0;
 467         }
 468
 469         for (i = 0; i < num_pins; i++) {
 470                 desc = pin_desc_get(pctldev, pins[i]);
 471                 if (desc == NULL) {
 472                         dev_warn(pctldev->dev,
 473                                  "could not get pin desc for pin %d\n",
 474                                  pins[i]);
 475                         continue;
 476                 }
 477                 desc->mux_setting = NULL;
 478         }
 479
 480         ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 481 }
 482
 483 #ifdef CONFIG_DEBUG_FS
 484
 485 /* Called from pincontrol core */
 486 static int pinmux_functions_show(struct seq_file *s, void *what)
 487 {
 488         struct pinctrl_dev *pctldev = s->private;
 489         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 490         unsigned nfuncs;
 491         unsigned func_selector = 0;
 492
 493         if (!pmxops)
 494                 return 0;
 495
 496         mutex_lock(&pinctrl_mutex);
 497         nfuncs = pmxops->get_functions_count(pctldev);
 498         while (func_selector < nfuncs) {
 499                 const char *func = pmxops->get_function_name(pctldev,
 500                                                           func_selector);
 501                 const char * const *groups;
 502                 unsigned num_groups;
 503                 int ret;
 504                 int i;
 505
 506                 ret = pmxops->get_function_groups(pctldev, func_selector,
 507                                                   &groups, &num_groups);
 508                 if (ret)
 509                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 510                                    func);
 511
 512                 seq_printf(s, "function: %s, groups = [ ", func);
 513                 for (i = 0; i < num_groups; i++)
 514                         seq_printf(s, "%s ", groups[i]);
 515                 seq_puts(s, "]\n");
 516
 517                 func_selector++;
 518         }
 519
 520         mutex_unlock(&pinctrl_mutex);
 521
 522         return 0;
 523 }
 524
 525 static int pinmux_pins_show(struct seq_file *s, void *what)
 526 {
 527         struct pinctrl_dev *pctldev = s->private;
 528         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 529         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 530         unsigned i, pin;
 531
 532         if (!pmxops)
 533                 return 0;
 534
 535         seq_puts(s, "Pinmux settings per pin\n");
 536         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 537
 538         mutex_lock(&pinctrl_mutex);
 539
 540         /* The pin number can be retrived from the pin controller descriptor */
 541         for (i = 0; i < pctldev->desc->npins; i++) {
 542                 struct pin_desc *desc;
 543                 bool is_hog = false;
 544
 545                 pin = pctldev->desc->pins[i].number;
 546                 desc = pin_desc_get(pctldev, pin);
 547                 /* Skip if we cannot search the pin */
 548                 if (desc == NULL)
 549                         continue;
 550
 551                 if (desc->mux_owner &&
 552                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 553                         is_hog = true;
 554
 555                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 556                            desc->name ? desc->name : "unnamed",
 557                            desc->mux_owner ? desc->mux_owner
 558                                 : "(MUX UNCLAIMED)",
 559                            desc->gpio_owner ? desc->gpio_owner
 560                                 : "(GPIO UNCLAIMED)",
 561                            is_hog ? " (HOG)" : "");
 562
 563                 if (desc->mux_setting)
 564                         seq_printf(s, " function %s group %s\n",
 565                                    pmxops->get_function_name(pctldev,
 566                                         desc->mux_setting->func),
 567                                    pctlops->get_group_name(pctldev,
 568                                         desc->mux_setting->group));
 569                 else
 570                         seq_printf(s, "\n");
 571         }
 572
 573         mutex_unlock(&pinctrl_mutex);
 574
 575         return 0;
 576 }
 577
 578 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 579 {
 580         seq_printf(s, "group %s\nfunction %s\n",
 581                 map->data.mux.group ? map->data.mux.group : "(default)",
 582                 map->data.mux.function);
 583 }
 584
 585 void pinmux_show_setting(struct seq_file *s,
 586                          struct pinctrl_setting const *setting)
 587 {
 588         struct pinctrl_dev *pctldev = setting->pctldev;
 589         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 590         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 591
 592         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 593                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 594                    setting->data.mux.group,
 595                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 596                    setting->data.mux.func);
 597 }
 598
 599 static int pinmux_functions_open(struct inode *inode, struct file *file)
 600 {
 601         return single_open(file, pinmux_functions_show, inode->i_private);
 602 }
 603
 604 static int pinmux_pins_open(struct inode *inode, struct file *file)
 605 {
 606         return single_open(file, pinmux_pins_show, inode->i_private);
 607 }
 608
 609 static const struct file_operations pinmux_functions_ops = {
 610         .open           = pinmux_functions_open,
 611         .read           = seq_read,
 612         .llseek         = seq_lseek,
 613         .release        = single_release,
 614 };
 615
 616 static const struct file_operations pinmux_pins_ops = {
 617         .open           = pinmux_pins_open,
 618         .read           = seq_read,
 619         .llseek         = seq_lseek,
 620         .release        = single_release,
 621 };
 622
 623 void pinmux_init_device_debugfs(struct dentry *devroot,
 624                          struct pinctrl_dev *pctldev)
 625 {
 626         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 627                             devroot, pctldev, &pinmux_functions_ops);
 628         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 629                             devroot, pctldev, &pinmux_pins_ops);
 630 }
 631
 632 #endif /* CONFIG_DEBUG_FS */