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         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 318         char const * const *groups;
 319         unsigned num_groups;
 320         int ret;
 321         const char *group;
 322         int i;
 323         const unsigned *pins;
 324         unsigned num_pins;
 325
 326         if (!pmxops) {
 327                 dev_err(pctldev->dev, "does not support mux function\n");
 328                 return -EINVAL;
 329         }
 330
 331         ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 332         if (ret < 0) {
 333                 dev_err(pctldev->dev, "invalid function %s in map table\n",
 334                         map->data.mux.function);
 335                 return ret;
 336         }
 337         setting->data.mux.func = ret;
 338
 339         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 340                                           &groups, &num_groups);
 341         if (ret < 0) {
 342                 dev_err(pctldev->dev, "can't query groups for function %s\n",
 343                         map->data.mux.function);
 344                 return ret;
 345         }
 346         if (!num_groups) {
 347                 dev_err(pctldev->dev,
 348                         "function %s can't be selected on any group\n",
 349                         map->data.mux.function);
 350                 return -EINVAL;
 351         }
 352         if (map->data.mux.group) {
 353                 bool found = false;
 354                 group = map->data.mux.group;
 355                 for (i = 0; i < num_groups; i++) {
 356                         if (!strcmp(group, groups[i])) {
 357                                 found = true;
 358                                 break;
 359                         }
 360                 }
 361                 if (!found) {
 362                         dev_err(pctldev->dev,
 363                                 "invalid group \"%s\" for function \"%s\"\n",
 364                                 group, map->data.mux.function);
 365                         return -EINVAL;
 366                 }
 367         } else {
 368                 group = groups[0];
 369         }
 370
 371         ret = pinctrl_get_group_selector(pctldev, group);
 372         if (ret < 0) {
 373                 dev_err(pctldev->dev, "invalid group %s in map table\n",
 374                         map->data.mux.group);
 375                 return ret;
 376         }
 377         setting->data.mux.group = ret;
 378
 379         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 380                                       &num_pins);
 381         if (ret) {
 382                 dev_err(pctldev->dev,
 383                         "could not get pins for device %s group selector %d\n",
 384                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 385                         return -ENODEV;
 386         }
 387
 388         /* Try to allocate all pins in this group, one by one */
 389         for (i = 0; i < num_pins; i++) {
 390                 ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
 391                 if (ret) {
 392                         dev_err(pctldev->dev,
 393                                 "could not request pin %d on device %s\n",
 394                                 pins[i], pinctrl_dev_get_name(pctldev));
 395                         /* On error release all taken pins */
 396                         i--; /* this pin just failed */
 397                         for (; i >= 0; i--)
 398                                 pin_free(pctldev, pins[i], NULL);
 399                         return -ENODEV;
 400                 }
 401         }
 402
 403         return 0;
 404 }
 405
 406 void pinmux_free_setting(struct pinctrl_setting const *setting)
 407 {
 408         struct pinctrl_dev *pctldev = setting->pctldev;
 409         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 410         const unsigned *pins;
 411         unsigned num_pins;
 412         int ret;
 413         int i;
 414
 415         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 416                                       &pins, &num_pins);
 417         if (ret) {
 418                 dev_err(pctldev->dev,
 419                         "could not get pins for device %s group selector %d\n",
 420                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 421                 return;
 422         }
 423
 424         for (i = 0; i < num_pins; i++)
 425                 pin_free(pctldev, pins[i], NULL);
 426 }
 427
 428 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 429 {
 430         struct pinctrl_dev *pctldev = setting->pctldev;
 431         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 432         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 433         int ret;
 434         const unsigned *pins;
 435         unsigned num_pins;
 436         int i;
 437         struct pin_desc *desc;
 438
 439         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 440                                       &pins, &num_pins);
 441         if (ret) {
 442                 /* errors only affect debug data, so just warn */
 443                 dev_warn(pctldev->dev,
 444                          "could not get pins for group selector %d\n",
 445                          setting->data.mux.group);
 446                 num_pins = 0;
 447         }
 448
 449         for (i = 0; i < num_pins; i++) {
 450                 desc = pin_desc_get(pctldev, pins[i]);
 451                 if (desc == NULL) {
 452                         dev_warn(pctldev->dev,
 453                                  "could not get pin desc for pin %d\n",
 454                                  pins[i]);
 455                         continue;
 456                 }
 457                 desc->mux_setting = &(setting->data.mux);
 458         }
 459
 460         return ops->enable(pctldev, setting->data.mux.func,
 461                            setting->data.mux.group);
 462 }
 463
 464 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 465 {
 466         struct pinctrl_dev *pctldev = setting->pctldev;
 467         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 468         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 469         int ret;
 470         const unsigned *pins;
 471         unsigned num_pins;
 472         int i;
 473         struct pin_desc *desc;
 474
 475         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 476                                       &pins, &num_pins);
 477         if (ret) {
 478                 /* errors only affect debug data, so just warn */
 479                 dev_warn(pctldev->dev,
 480                          "could not get pins for group selector %d\n",
 481                          setting->data.mux.group);
 482                 num_pins = 0;
 483         }
 484
 485         for (i = 0; i < num_pins; i++) {
 486                 desc = pin_desc_get(pctldev, pins[i]);
 487                 if (desc == NULL) {
 488                         dev_warn(pctldev->dev,
 489                                  "could not get pin desc for pin %d\n",
 490                                  pins[i]);
 491                         continue;
 492                 }
 493                 desc->mux_setting = NULL;
 494         }
 495
 496         if (ops->disable)
 497                 ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 498 }
 499
 500 #ifdef CONFIG_DEBUG_FS
 501
 502 /* Called from pincontrol core */
 503 static int pinmux_functions_show(struct seq_file *s, void *what)
 504 {
 505         struct pinctrl_dev *pctldev = s->private;
 506         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 507         unsigned nfuncs;
 508         unsigned func_selector = 0;
 509
 510         if (!pmxops)
 511                 return 0;
 512
 513         mutex_lock(&pinctrl_mutex);
 514         nfuncs = pmxops->get_functions_count(pctldev);
 515         while (func_selector < nfuncs) {
 516                 const char *func = pmxops->get_function_name(pctldev,
 517                                                           func_selector);
 518                 const char * const *groups;
 519                 unsigned num_groups;
 520                 int ret;
 521                 int i;
 522
 523                 ret = pmxops->get_function_groups(pctldev, func_selector,
 524                                                   &groups, &num_groups);
 525                 if (ret)
 526                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 527                                    func);
 528
 529                 seq_printf(s, "function: %s, groups = [ ", func);
 530                 for (i = 0; i < num_groups; i++)
 531                         seq_printf(s, "%s ", groups[i]);
 532                 seq_puts(s, "]\n");
 533
 534                 func_selector++;
 535         }
 536
 537         mutex_unlock(&pinctrl_mutex);
 538
 539         return 0;
 540 }
 541
 542 static int pinmux_pins_show(struct seq_file *s, void *what)
 543 {
 544         struct pinctrl_dev *pctldev = s->private;
 545         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 546         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 547         unsigned i, pin;
 548
 549         if (!pmxops)
 550                 return 0;
 551
 552         seq_puts(s, "Pinmux settings per pin\n");
 553         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 554
 555         mutex_lock(&pinctrl_mutex);
 556
 557         /* The pin number can be retrived from the pin controller descriptor */
 558         for (i = 0; i < pctldev->desc->npins; i++) {
 559                 struct pin_desc *desc;
 560                 bool is_hog = false;
 561
 562                 pin = pctldev->desc->pins[i].number;
 563                 desc = pin_desc_get(pctldev, pin);
 564                 /* Skip if we cannot search the pin */
 565                 if (desc == NULL)
 566                         continue;
 567
 568                 if (desc->mux_owner &&
 569                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 570                         is_hog = true;
 571
 572                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 573                            desc->name ? desc->name : "unnamed",
 574                            desc->mux_owner ? desc->mux_owner
 575                                 : "(MUX UNCLAIMED)",
 576                            desc->gpio_owner ? desc->gpio_owner
 577                                 : "(GPIO UNCLAIMED)",
 578                            is_hog ? " (HOG)" : "");
 579
 580                 if (desc->mux_setting)
 581                         seq_printf(s, " function %s group %s\n",
 582                                    pmxops->get_function_name(pctldev,
 583                                         desc->mux_setting->func),
 584                                    pctlops->get_group_name(pctldev,
 585                                         desc->mux_setting->group));
 586                 else
 587                         seq_printf(s, "\n");
 588         }
 589
 590         mutex_unlock(&pinctrl_mutex);
 591
 592         return 0;
 593 }
 594
 595 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 596 {
 597         seq_printf(s, "group %s\nfunction %s\n",
 598                 map->data.mux.group ? map->data.mux.group : "(default)",
 599                 map->data.mux.function);
 600 }
 601
 602 void pinmux_show_setting(struct seq_file *s,
 603                          struct pinctrl_setting const *setting)
 604 {
 605         struct pinctrl_dev *pctldev = setting->pctldev;
 606         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 607         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 608
 609         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 610                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 611                    setting->data.mux.group,
 612                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 613                    setting->data.mux.func);
 614 }
 615
 616 static int pinmux_functions_open(struct inode *inode, struct file *file)
 617 {
 618         return single_open(file, pinmux_functions_show, inode->i_private);
 619 }
 620
 621 static int pinmux_pins_open(struct inode *inode, struct file *file)
 622 {
 623         return single_open(file, pinmux_pins_show, inode->i_private);
 624 }
 625
 626 static const struct file_operations pinmux_functions_ops = {
 627         .open           = pinmux_functions_open,
 628         .read           = seq_read,
 629         .llseek         = seq_lseek,
 630         .release        = single_release,
 631 };
 632
 633 static const struct file_operations pinmux_pins_ops = {
 634         .open           = pinmux_pins_open,
 635         .read           = seq_read,
 636         .llseek         = seq_lseek,
 637         .release        = single_release,
 638 };
 639
 640 void pinmux_init_device_debugfs(struct dentry *devroot,
 641                          struct pinctrl_dev *pctldev)
 642 {
 643         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 644                             devroot, pctldev, &pinmux_functions_ops);
 645         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 646                             devroot, pctldev, &pinmux_pins_ops);
 647 }
 648
 649 #endif /* CONFIG_DEBUG_FS */