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->set_mux) {
  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                 /*
 198                  * A pin should not be freed more times than allocated.
 199                  */
 200                 if (WARN_ON(!desc->mux_usecount))
 201                         return NULL;
 202                 desc->mux_usecount--;
 203                 if (desc->mux_usecount)
 204                         return NULL;
 205         }
 206
 207         /*
 208          * If there is no kind of request function for the pin we just assume
 209          * we got it by default and proceed.
 210          */
 211         if (gpio_range && ops->gpio_disable_free)
 212                 ops->gpio_disable_free(pctldev, gpio_range, pin);
 213         else if (ops->free)
 214                 ops->free(pctldev, pin);
 215
 216         if (gpio_range) {
 217                 owner = desc->gpio_owner;
 218                 desc->gpio_owner = NULL;
 219         } else {
 220                 owner = desc->mux_owner;
 221                 desc->mux_owner = NULL;
 222                 desc->mux_setting = NULL;
 223         }
 224
 225         module_put(pctldev->owner);
 226
 227         return owner;
 228 }
 229
 230 /**
 231  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 232  * @pctldev: pin controller device affected
 233  * @pin: the pin to mux in for GPIO
 234  * @range: the applicable GPIO range
 235  */
 236 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 237                         struct pinctrl_gpio_range *range,
 238                         unsigned pin, unsigned gpio)
 239 {
 240         const char *owner;
 241         int ret;
 242
 243         /* Conjure some name stating what chip and pin this is taken by */
 244         owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
 245         if (!owner)
 246                 return -EINVAL;
 247
 248         ret = pin_request(pctldev, pin, owner, range);
 249         if (ret < 0)
 250                 kfree(owner);
 251
 252         return ret;
 253 }
 254
 255 /**
 256  * pinmux_free_gpio() - release a pin from GPIO muxing
 257  * @pctldev: the pin controller device for the pin
 258  * @pin: the affected currently GPIO-muxed in pin
 259  * @range: applicable GPIO range
 260  */
 261 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 262                       struct pinctrl_gpio_range *range)
 263 {
 264         const char *owner;
 265
 266         owner = pin_free(pctldev, pin, range);
 267         kfree(owner);
 268 }
 269
 270 /**
 271  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 272  * @pctldev: the pin controller handling this pin
 273  * @range: applicable GPIO range
 274  * @pin: the affected GPIO pin in this controller
 275  * @input: true if we set the pin as input, false for output
 276  */
 277 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 278                           struct pinctrl_gpio_range *range,
 279                           unsigned pin, bool input)
 280 {
 281         const struct pinmux_ops *ops;
 282         int ret;
 283
 284         ops = pctldev->desc->pmxops;
 285
 286         if (ops->gpio_set_direction)
 287                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 288         else
 289                 ret = 0;
 290
 291         return ret;
 292 }
 293
 294 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 295                                         const char *function)
 296 {
 297         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 298         unsigned nfuncs = ops->get_functions_count(pctldev);
 299         unsigned selector = 0;
 300
 301         /* See if this pctldev has this function */
 302         while (selector < nfuncs) {
 303                 const char *fname = ops->get_function_name(pctldev,
 304                                                            selector);
 305
 306                 if (!strcmp(function, fname))
 307                         return selector;
 308
 309                 selector++;
 310         }
 311
 312         pr_err("%s does not support function %s\n",
 313                pinctrl_dev_get_name(pctldev), function);
 314         return -EINVAL;
 315 }
 316
 317 int pinmux_map_to_setting(struct pinctrl_map const *map,
 318                           struct pinctrl_setting *setting)
 319 {
 320         struct pinctrl_dev *pctldev = setting->pctldev;
 321         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 322         char const * const *groups;
 323         unsigned num_groups;
 324         int ret;
 325         const char *group;
 326         int i;
 327
 328         if (!pmxops) {
 329                 dev_err(pctldev->dev, "does not support mux function\n");
 330                 return -EINVAL;
 331         }
 332
 333         ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 334         if (ret < 0) {
 335                 dev_err(pctldev->dev, "invalid function %s in map table\n",
 336                         map->data.mux.function);
 337                 return ret;
 338         }
 339         setting->data.mux.func = ret;
 340
 341         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 342                                           &groups, &num_groups);
 343         if (ret < 0) {
 344                 dev_err(pctldev->dev, "can't query groups for function %s\n",
 345                         map->data.mux.function);
 346                 return ret;
 347         }
 348         if (!num_groups) {
 349                 dev_err(pctldev->dev,
 350                         "function %s can't be selected on any group\n",
 351                         map->data.mux.function);
 352                 return -EINVAL;
 353         }
 354         if (map->data.mux.group) {
 355                 bool found = false;
 356                 group = map->data.mux.group;
 357                 for (i = 0; i < num_groups; i++) {
 358                         if (!strcmp(group, groups[i])) {
 359                                 found = true;
 360                                 break;
 361                         }
 362                 }
 363                 if (!found) {
 364                         dev_err(pctldev->dev,
 365                                 "invalid group \"%s\" for function \"%s\"\n",
 366                                 group, map->data.mux.function);
 367                         return -EINVAL;
 368                 }
 369         } else {
 370                 group = groups[0];
 371         }
 372
 373         ret = pinctrl_get_group_selector(pctldev, group);
 374         if (ret < 0) {
 375                 dev_err(pctldev->dev, "invalid group %s in map table\n",
 376                         map->data.mux.group);
 377                 return ret;
 378         }
 379         setting->data.mux.group = ret;
 380
 381         return 0;
 382 }
 383
 384 void pinmux_free_setting(struct pinctrl_setting const *setting)
 385 {
 386         /* This function is currently unused */
 387 }
 388
 389 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 390 {
 391         struct pinctrl_dev *pctldev = setting->pctldev;
 392         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 393         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 394         int ret = 0;
 395         const unsigned *pins = NULL;
 396         unsigned num_pins = 0;
 397         int i;
 398         struct pin_desc *desc;
 399
 400         if (pctlops->get_group_pins)
 401                 ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 402                                               &pins, &num_pins);
 403
 404         if (ret) {
 405                 const char *gname;
 406
 407                 /* errors only affect debug data, so just warn */
 408                 gname = pctlops->get_group_name(pctldev,
 409                                                 setting->data.mux.group);
 410                 dev_warn(pctldev->dev,
 411                          "could not get pins for group %s\n",
 412                          gname);
 413                 num_pins = 0;
 414         }
 415
 416         /* Try to allocate all pins in this group, one by one */
 417         for (i = 0; i < num_pins; i++) {
 418                 ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
 419                 if (ret) {
 420                         const char *gname;
 421                         const char *pname;
 422
 423                         desc = pin_desc_get(pctldev, pins[i]);
 424                         pname = desc ? desc->name : "non-existing";
 425                         gname = pctlops->get_group_name(pctldev,
 426                                                 setting->data.mux.group);
 427                         dev_err(pctldev->dev,
 428                                 "could not request pin %d (%s) from group %s "
 429                                 " on device %s\n",
 430                                 pins[i], pname, gname,
 431                                 pinctrl_dev_get_name(pctldev));
 432                         goto err_pin_request;
 433                 }
 434         }
 435
 436         /* Now that we have acquired the pins, encode the mux setting */
 437         for (i = 0; i < num_pins; i++) {
 438                 desc = pin_desc_get(pctldev, pins[i]);
 439                 if (desc == NULL) {
 440                         dev_warn(pctldev->dev,
 441                                  "could not get pin desc for pin %d\n",
 442                                  pins[i]);
 443                         continue;
 444                 }
 445                 desc->mux_setting = &(setting->data.mux);
 446         }
 447
 448         ret = ops->set_mux(pctldev, setting->data.mux.func,
 449                            setting->data.mux.group);
 450
 451         if (ret)
 452                 goto err_set_mux;
 453
 454         return 0;
 455
 456 err_set_mux:
 457         for (i = 0; i < num_pins; i++) {
 458                 desc = pin_desc_get(pctldev, pins[i]);
 459                 if (desc)
 460                         desc->mux_setting = NULL;
 461         }
 462 err_pin_request:
 463         /* On error release all taken pins */
 464         while (--i >= 0)
 465                 pin_free(pctldev, pins[i], NULL);
 466
 467         return ret;
 468 }
 469
 470 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 471 {
 472         struct pinctrl_dev *pctldev = setting->pctldev;
 473         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 474         int ret = 0;
 475         const unsigned *pins = NULL;
 476         unsigned num_pins = 0;
 477         int i;
 478         struct pin_desc *desc;
 479
 480         if (pctlops->get_group_pins)
 481                 ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 482                                               &pins, &num_pins);
 483         if (ret) {
 484                 const char *gname;
 485
 486                 /* errors only affect debug data, so just warn */
 487                 gname = pctlops->get_group_name(pctldev,
 488                                                 setting->data.mux.group);
 489                 dev_warn(pctldev->dev,
 490                          "could not get pins for group %s\n",
 491                          gname);
 492                 num_pins = 0;
 493         }
 494
 495         /* Flag the descs that no setting is active */
 496         for (i = 0; i < num_pins; i++) {
 497                 desc = pin_desc_get(pctldev, pins[i]);
 498                 if (desc == NULL) {
 499                         dev_warn(pctldev->dev,
 500                                  "could not get pin desc for pin %d\n",
 501                                  pins[i]);
 502                         continue;
 503                 }
 504                 if (desc->mux_setting == &(setting->data.mux)) {
 505                         desc->mux_setting = NULL;
 506                         /* And release the pin */
 507                         pin_free(pctldev, pins[i], NULL);
 508                 } else {
 509                         const char *gname;
 510
 511                         gname = pctlops->get_group_name(pctldev,
 512                                                 setting->data.mux.group);
 513                         dev_warn(pctldev->dev,
 514                                  "not freeing pin %d (%s) as part of "
 515                                  "deactivating group %s - it is already "
 516                                  "used for some other setting",
 517                                  pins[i], desc->name, gname);
 518                 }
 519         }
 520 }
 521
 522 #ifdef CONFIG_DEBUG_FS
 523
 524 /* Called from pincontrol core */
 525 static int pinmux_functions_show(struct seq_file *s, void *what)
 526 {
 527         struct pinctrl_dev *pctldev = s->private;
 528         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 529         unsigned nfuncs;
 530         unsigned func_selector = 0;
 531
 532         if (!pmxops)
 533                 return 0;
 534
 535         mutex_lock(&pctldev->mutex);
 536         nfuncs = pmxops->get_functions_count(pctldev);
 537         while (func_selector < nfuncs) {
 538                 const char *func = pmxops->get_function_name(pctldev,
 539                                                           func_selector);
 540                 const char * const *groups;
 541                 unsigned num_groups;
 542                 int ret;
 543                 int i;
 544
 545                 ret = pmxops->get_function_groups(pctldev, func_selector,
 546                                                   &groups, &num_groups);
 547                 if (ret)
 548                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 549                                    func);
 550
 551                 seq_printf(s, "function: %s, groups = [ ", func);
 552                 for (i = 0; i < num_groups; i++)
 553                         seq_printf(s, "%s ", groups[i]);
 554                 seq_puts(s, "]\n");
 555
 556                 func_selector++;
 557         }
 558
 559         mutex_unlock(&pctldev->mutex);
 560
 561         return 0;
 562 }
 563
 564 static int pinmux_pins_show(struct seq_file *s, void *what)
 565 {
 566         struct pinctrl_dev *pctldev = s->private;
 567         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 568         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 569         unsigned i, pin;
 570
 571         if (!pmxops)
 572                 return 0;
 573
 574         seq_puts(s, "Pinmux settings per pin\n");
 575         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 576
 577         mutex_lock(&pctldev->mutex);
 578
 579         /* The pin number can be retrived from the pin controller descriptor */
 580         for (i = 0; i < pctldev->desc->npins; i++) {
 581                 struct pin_desc *desc;
 582                 bool is_hog = false;
 583
 584                 pin = pctldev->desc->pins[i].number;
 585                 desc = pin_desc_get(pctldev, pin);
 586                 /* Skip if we cannot search the pin */
 587                 if (desc == NULL)
 588                         continue;
 589
 590                 if (desc->mux_owner &&
 591                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 592                         is_hog = true;
 593
 594                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 595                            desc->name ? desc->name : "unnamed",
 596                            desc->mux_owner ? desc->mux_owner
 597                                 : "(MUX UNCLAIMED)",
 598                            desc->gpio_owner ? desc->gpio_owner
 599                                 : "(GPIO UNCLAIMED)",
 600                            is_hog ? " (HOG)" : "");
 601
 602                 if (desc->mux_setting)
 603                         seq_printf(s, " function %s group %s\n",
 604                                    pmxops->get_function_name(pctldev,
 605                                         desc->mux_setting->func),
 606                                    pctlops->get_group_name(pctldev,
 607                                         desc->mux_setting->group));
 608                 else
 609                         seq_printf(s, "\n");
 610         }
 611
 612         mutex_unlock(&pctldev->mutex);
 613
 614         return 0;
 615 }
 616
 617 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 618 {
 619         seq_printf(s, "group %s\nfunction %s\n",
 620                 map->data.mux.group ? map->data.mux.group : "(default)",
 621                 map->data.mux.function);
 622 }
 623
 624 void pinmux_show_setting(struct seq_file *s,
 625                          struct pinctrl_setting const *setting)
 626 {
 627         struct pinctrl_dev *pctldev = setting->pctldev;
 628         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 629         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 630
 631         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 632                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 633                    setting->data.mux.group,
 634                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 635                    setting->data.mux.func);
 636 }
 637
 638 static int pinmux_functions_open(struct inode *inode, struct file *file)
 639 {
 640         return single_open(file, pinmux_functions_show, inode->i_private);
 641 }
 642
 643 static int pinmux_pins_open(struct inode *inode, struct file *file)
 644 {
 645         return single_open(file, pinmux_pins_show, inode->i_private);
 646 }
 647
 648 static const struct file_operations pinmux_functions_ops = {
 649         .open           = pinmux_functions_open,
 650         .read           = seq_read,
 651         .llseek         = seq_lseek,
 652         .release        = single_release,
 653 };
 654
 655 static const struct file_operations pinmux_pins_ops = {
 656         .open           = pinmux_pins_open,
 657         .read           = seq_read,
 658         .llseek         = seq_lseek,
 659         .release        = single_release,
 660 };
 661
 662 void pinmux_init_device_debugfs(struct dentry *devroot,
 663                          struct pinctrl_dev *pctldev)
 664 {
 665         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 666                             devroot, pctldev, &pinmux_functions_ops);
 667         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 668                             devroot, pctldev, &pinmux_pins_ops);
 669 }
 670
 671 #endif /* CONFIG_DEBUG_FS */