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                 dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
  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 %d is not registered so it cannot be requested\n",
  95                         pin);
  96                 goto out;
  97         }
  98
  99         dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
 100                 pin, desc->name, owner);
 101
 102         if (gpio_range) {
 103                 /* There's no need to support multiple GPIO requests */
 104                 if (desc->gpio_owner) {
 105                         dev_err(pctldev->dev,
 106                                 "pin %s already requested by %s; cannot claim for %s\n",
 107                                 desc->name, desc->gpio_owner, owner);
 108                         goto out;
 109                 }
 110
 111                 desc->gpio_owner = owner;
 112         } else {
 113                 if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
 114                         dev_err(pctldev->dev,
 115                                 "pin %s already requested by %s; cannot claim for %s\n",
 116                                 desc->name, desc->mux_owner, owner);
 117                         goto out;
 118                 }
 119
 120                 desc->mux_usecount++;
 121                 if (desc->mux_usecount > 1)
 122                         return 0;
 123
 124                 desc->mux_owner = owner;
 125         }
 126
 127         /* Let each pin increase references to this module */
 128         if (!try_module_get(pctldev->owner)) {
 129                 dev_err(pctldev->dev,
 130                         "could not increase module refcount for pin %d\n",
 131                         pin);
 132                 status = -EINVAL;
 133                 goto out_free_pin;
 134         }
 135
 136         /*
 137          * If there is no kind of request function for the pin we just assume
 138          * we got it by default and proceed.
 139          */
 140         if (gpio_range && ops->gpio_request_enable)
 141                 /* This requests and enables a single GPIO pin */
 142                 status = ops->gpio_request_enable(pctldev, gpio_range, pin);
 143         else if (ops->request)
 144                 status = ops->request(pctldev, pin);
 145         else
 146                 status = 0;
 147
 148         if (status) {
 149                 dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
 150                 module_put(pctldev->owner);
 151         }
 152
 153 out_free_pin:
 154         if (status) {
 155                 if (gpio_range) {
 156                         desc->gpio_owner = NULL;
 157                 } else {
 158                         desc->mux_usecount--;
 159                         if (!desc->mux_usecount)
 160                                 desc->mux_owner = NULL;
 161                 }
 162         }
 163 out:
 164         if (status)
 165                 dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
 166                         pin, owner, status);
 167
 168         return status;
 169 }
 170
 171 /**
 172  * pin_free() - release a single muxed in pin so something else can be muxed
 173  * @pctldev: pin controller device handling this pin
 174  * @pin: the pin to free
 175  * @gpio_range: the range matching the GPIO pin if this is a request for a
 176  *      single GPIO pin
 177  *
 178  * This function returns a pointer to the previous owner. This is used
 179  * for callers that dynamically allocate an owner name so it can be freed
 180  * once the pin is free. This is done for GPIO request functions.
 181  */
 182 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 183                             struct pinctrl_gpio_range *gpio_range)
 184 {
 185         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 186         struct pin_desc *desc;
 187         const char *owner;
 188
 189         desc = pin_desc_get(pctldev, pin);
 190         if (desc == NULL) {
 191                 dev_err(pctldev->dev,
 192                         "pin is not registered so it cannot be freed\n");
 193                 return NULL;
 194         }
 195
 196         if (!gpio_range) {
 197                 desc->mux_usecount--;
 198                 if (desc->mux_usecount)
 199                         return NULL;
 200         }
 201
 202         /*
 203          * If there is no kind of request function for the pin we just assume
 204          * we got it by default and proceed.
 205          */
 206         if (gpio_range && ops->gpio_disable_free)
 207                 ops->gpio_disable_free(pctldev, gpio_range, pin);
 208         else if (ops->free)
 209                 ops->free(pctldev, pin);
 210
 211         if (gpio_range) {
 212                 owner = desc->gpio_owner;
 213                 desc->gpio_owner = NULL;
 214         } else {
 215                 owner = desc->mux_owner;
 216                 desc->mux_owner = NULL;
 217                 desc->mux_setting = NULL;
 218         }
 219
 220         module_put(pctldev->owner);
 221
 222         return owner;
 223 }
 224
 225 /**
 226  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 227  * @pctldev: pin controller device affected
 228  * @pin: the pin to mux in for GPIO
 229  * @range: the applicable GPIO range
 230  */
 231 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 232                         struct pinctrl_gpio_range *range,
 233                         unsigned pin, unsigned gpio)
 234 {
 235         const char *owner;
 236         int ret;
 237
 238         /* Conjure some name stating what chip and pin this is taken by */
 239         owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
 240         if (!owner)
 241                 return -EINVAL;
 242
 243         ret = pin_request(pctldev, pin, owner, range);
 244         if (ret < 0)
 245                 kfree(owner);
 246
 247         return ret;
 248 }
 249
 250 /**
 251  * pinmux_free_gpio() - release a pin from GPIO muxing
 252  * @pctldev: the pin controller device for the pin
 253  * @pin: the affected currently GPIO-muxed in pin
 254  * @range: applicable GPIO range
 255  */
 256 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 257                       struct pinctrl_gpio_range *range)
 258 {
 259         const char *owner;
 260
 261         owner = pin_free(pctldev, pin, range);
 262         kfree(owner);
 263 }
 264
 265 /**
 266  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 267  * @pctldev: the pin controller handling this pin
 268  * @range: applicable GPIO range
 269  * @pin: the affected GPIO pin in this controller
 270  * @input: true if we set the pin as input, false for output
 271  */
 272 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 273                           struct pinctrl_gpio_range *range,
 274                           unsigned pin, bool input)
 275 {
 276         const struct pinmux_ops *ops;
 277         int ret;
 278
 279         ops = pctldev->desc->pmxops;
 280
 281         if (ops->gpio_set_direction)
 282                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 283         else
 284                 ret = 0;
 285
 286         return ret;
 287 }
 288
 289 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 290                                         const char *function)
 291 {
 292         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 293         unsigned nfuncs = ops->get_functions_count(pctldev);
 294         unsigned selector = 0;
 295
 296         /* See if this pctldev has this function */
 297         while (selector < nfuncs) {
 298                 const char *fname = ops->get_function_name(pctldev,
 299                                                            selector);
 300
 301                 if (!strcmp(function, fname))
 302                         return selector;
 303
 304                 selector++;
 305         }
 306
 307         pr_err("%s does not support function %s\n",
 308                pinctrl_dev_get_name(pctldev), function);
 309         return -EINVAL;
 310 }
 311
 312 int pinmux_map_to_setting(struct pinctrl_map const *map,
 313                           struct pinctrl_setting *setting)
 314 {
 315         struct pinctrl_dev *pctldev = setting->pctldev;
 316         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 317         char const * const *groups;
 318         unsigned num_groups;
 319         int ret;
 320         const char *group;
 321         int i;
 322
 323         if (!pmxops) {
 324                 dev_err(pctldev->dev, "does not support mux function\n");
 325                 return -EINVAL;
 326         }
 327
 328         ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 329         if (ret < 0) {
 330                 dev_err(pctldev->dev, "invalid function %s in map table\n",
 331                         map->data.mux.function);
 332                 return ret;
 333         }
 334         setting->data.mux.func = ret;
 335
 336         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 337                                           &groups, &num_groups);
 338         if (ret < 0) {
 339                 dev_err(pctldev->dev, "can't query groups for function %s\n",
 340                         map->data.mux.function);
 341                 return ret;
 342         }
 343         if (!num_groups) {
 344                 dev_err(pctldev->dev,
 345                         "function %s can't be selected on any group\n",
 346                         map->data.mux.function);
 347                 return -EINVAL;
 348         }
 349         if (map->data.mux.group) {
 350                 bool found = false;
 351                 group = map->data.mux.group;
 352                 for (i = 0; i < num_groups; i++) {
 353                         if (!strcmp(group, groups[i])) {
 354                                 found = true;
 355                                 break;
 356                         }
 357                 }
 358                 if (!found) {
 359                         dev_err(pctldev->dev,
 360                                 "invalid group \"%s\" for function \"%s\"\n",
 361                                 group, map->data.mux.function);
 362                         return -EINVAL;
 363                 }
 364         } else {
 365                 group = groups[0];
 366         }
 367
 368         ret = pinctrl_get_group_selector(pctldev, group);
 369         if (ret < 0) {
 370                 dev_err(pctldev->dev, "invalid group %s in map table\n",
 371                         map->data.mux.group);
 372                 return ret;
 373         }
 374         setting->data.mux.group = ret;
 375
 376         return 0;
 377 }
 378
 379 void pinmux_free_setting(struct pinctrl_setting const *setting)
 380 {
 381         /* This function is currently unused */
 382 }
 383
 384 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 385 {
 386         struct pinctrl_dev *pctldev = setting->pctldev;
 387         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 388         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 389         int ret;
 390         const unsigned *pins;
 391         unsigned num_pins;
 392         int i;
 393         struct pin_desc *desc;
 394
 395         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 396                                       &pins, &num_pins);
 397         if (ret) {
 398                 /* errors only affect debug data, so just warn */
 399                 dev_warn(pctldev->dev,
 400                          "could not get pins for group selector %d\n",
 401                          setting->data.mux.group);
 402                 num_pins = 0;
 403         }
 404
 405         /* Try to allocate all pins in this group, one by one */
 406         for (i = 0; i < num_pins; i++) {
 407                 ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
 408                 if (ret) {
 409                         dev_err(pctldev->dev,
 410                                 "could not request pin %d on device %s\n",
 411                                 pins[i], pinctrl_dev_get_name(pctldev));
 412                         goto err_pin_request;
 413                 }
 414         }
 415
 416         /* Now that we have acquired the pins, encode the mux setting */
 417         for (i = 0; i < num_pins; i++) {
 418                 desc = pin_desc_get(pctldev, pins[i]);
 419                 if (desc == NULL) {
 420                         dev_warn(pctldev->dev,
 421                                  "could not get pin desc for pin %d\n",
 422                                  pins[i]);
 423                         continue;
 424                 }
 425                 desc->mux_setting = &(setting->data.mux);
 426         }
 427
 428         ret = ops->enable(pctldev, setting->data.mux.func,
 429                           setting->data.mux.group);
 430
 431         if (ret)
 432                 goto err_enable;
 433
 434         return 0;
 435
 436 err_enable:
 437         for (i = 0; i < num_pins; i++) {
 438                 desc = pin_desc_get(pctldev, pins[i]);
 439                 if (desc)
 440                         desc->mux_setting = NULL;
 441         }
 442 err_pin_request:
 443         /* On error release all taken pins */
 444         while (--i >= 0)
 445                 pin_free(pctldev, pins[i], NULL);
 446
 447         return ret;
 448 }
 449
 450 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 451 {
 452         struct pinctrl_dev *pctldev = setting->pctldev;
 453         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 454         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 455         int ret;
 456         const unsigned *pins;
 457         unsigned num_pins;
 458         int i;
 459         struct pin_desc *desc;
 460
 461         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 462                                       &pins, &num_pins);
 463         if (ret) {
 464                 /* errors only affect debug data, so just warn */
 465                 dev_warn(pctldev->dev,
 466                          "could not get pins for group selector %d\n",
 467                          setting->data.mux.group);
 468                 num_pins = 0;
 469         }
 470
 471         /* Flag the descs that no setting is active */
 472         for (i = 0; i < num_pins; i++) {
 473                 desc = pin_desc_get(pctldev, pins[i]);
 474                 if (desc == NULL) {
 475                         dev_warn(pctldev->dev,
 476                                  "could not get pin desc for pin %d\n",
 477                                  pins[i]);
 478                         continue;
 479                 }
 480                 desc->mux_setting = NULL;
 481         }
 482
 483         /* And release the pins */
 484         for (i = 0; i < num_pins; i++)
 485                 pin_free(pctldev, pins[i], NULL);
 486
 487         if (ops->disable)
 488                 ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 489 }
 490
 491 #ifdef CONFIG_DEBUG_FS
 492
 493 /* Called from pincontrol core */
 494 static int pinmux_functions_show(struct seq_file *s, void *what)
 495 {
 496         struct pinctrl_dev *pctldev = s->private;
 497         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 498         unsigned nfuncs;
 499         unsigned func_selector = 0;
 500
 501         if (!pmxops)
 502                 return 0;
 503
 504         mutex_lock(&pinctrl_mutex);
 505         nfuncs = pmxops->get_functions_count(pctldev);
 506         while (func_selector < nfuncs) {
 507                 const char *func = pmxops->get_function_name(pctldev,
 508                                                           func_selector);
 509                 const char * const *groups;
 510                 unsigned num_groups;
 511                 int ret;
 512                 int i;
 513
 514                 ret = pmxops->get_function_groups(pctldev, func_selector,
 515                                                   &groups, &num_groups);
 516                 if (ret)
 517                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 518                                    func);
 519
 520                 seq_printf(s, "function: %s, groups = [ ", func);
 521                 for (i = 0; i < num_groups; i++)
 522                         seq_printf(s, "%s ", groups[i]);
 523                 seq_puts(s, "]\n");
 524
 525                 func_selector++;
 526         }
 527
 528         mutex_unlock(&pinctrl_mutex);
 529
 530         return 0;
 531 }
 532
 533 static int pinmux_pins_show(struct seq_file *s, void *what)
 534 {
 535         struct pinctrl_dev *pctldev = s->private;
 536         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 537         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 538         unsigned i, pin;
 539
 540         if (!pmxops)
 541                 return 0;
 542
 543         seq_puts(s, "Pinmux settings per pin\n");
 544         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 545
 546         mutex_lock(&pinctrl_mutex);
 547
 548         /* The pin number can be retrived from the pin controller descriptor */
 549         for (i = 0; i < pctldev->desc->npins; i++) {
 550                 struct pin_desc *desc;
 551                 bool is_hog = false;
 552
 553                 pin = pctldev->desc->pins[i].number;
 554                 desc = pin_desc_get(pctldev, pin);
 555                 /* Skip if we cannot search the pin */
 556                 if (desc == NULL)
 557                         continue;
 558
 559                 if (desc->mux_owner &&
 560                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 561                         is_hog = true;
 562
 563                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 564                            desc->name ? desc->name : "unnamed",
 565                            desc->mux_owner ? desc->mux_owner
 566                                 : "(MUX UNCLAIMED)",
 567                            desc->gpio_owner ? desc->gpio_owner
 568                                 : "(GPIO UNCLAIMED)",
 569                            is_hog ? " (HOG)" : "");
 570
 571                 if (desc->mux_setting)
 572                         seq_printf(s, " function %s group %s\n",
 573                                    pmxops->get_function_name(pctldev,
 574                                         desc->mux_setting->func),
 575                                    pctlops->get_group_name(pctldev,
 576                                         desc->mux_setting->group));
 577                 else
 578                         seq_printf(s, "\n");
 579         }
 580
 581         mutex_unlock(&pinctrl_mutex);
 582
 583         return 0;
 584 }
 585
 586 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 587 {
 588         seq_printf(s, "group %s\nfunction %s\n",
 589                 map->data.mux.group ? map->data.mux.group : "(default)",
 590                 map->data.mux.function);
 591 }
 592
 593 void pinmux_show_setting(struct seq_file *s,
 594                          struct pinctrl_setting const *setting)
 595 {
 596         struct pinctrl_dev *pctldev = setting->pctldev;
 597         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 598         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 599
 600         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 601                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 602                    setting->data.mux.group,
 603                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 604                    setting->data.mux.func);
 605 }
 606
 607 static int pinmux_functions_open(struct inode *inode, struct file *file)
 608 {
 609         return single_open(file, pinmux_functions_show, inode->i_private);
 610 }
 611
 612 static int pinmux_pins_open(struct inode *inode, struct file *file)
 613 {
 614         return single_open(file, pinmux_pins_show, inode->i_private);
 615 }
 616
 617 static const struct file_operations pinmux_functions_ops = {
 618         .open           = pinmux_functions_open,
 619         .read           = seq_read,
 620         .llseek         = seq_lseek,
 621         .release        = single_release,
 622 };
 623
 624 static const struct file_operations pinmux_pins_ops = {
 625         .open           = pinmux_pins_open,
 626         .read           = seq_read,
 627         .llseek         = seq_lseek,
 628         .release        = single_release,
 629 };
 630
 631 void pinmux_init_device_debugfs(struct dentry *devroot,
 632                          struct pinctrl_dev *pctldev)
 633 {
 634         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 635                             devroot, pctldev, &pinmux_functions_ops);
 636         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 637                             devroot, pctldev, &pinmux_pins_ops);
 638 }
 639
 640 #endif /* CONFIG_DEBUG_FS */