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         char gpiostr[16];
 236         const char *owner;
 237         int ret;
 238
 239         /* Conjure some name stating what chip and pin this is taken by */
 240         snprintf(gpiostr, 15, "%s:%d", range->name, gpio);
 241
 242         owner = kstrdup(gpiostr, GFP_KERNEL);
 243         if (!owner)
 244                 return -EINVAL;
 245
 246         ret = pin_request(pctldev, pin, owner, range);
 247         if (ret < 0)
 248                 kfree(owner);
 249
 250         return ret;
 251 }
 252
 253 /**
 254  * pinmux_free_gpio() - release a pin from GPIO muxing
 255  * @pctldev: the pin controller device for the pin
 256  * @pin: the affected currently GPIO-muxed in pin
 257  * @range: applicable GPIO range
 258  */
 259 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 260                       struct pinctrl_gpio_range *range)
 261 {
 262         const char *owner;
 263
 264         owner = pin_free(pctldev, pin, range);
 265         kfree(owner);
 266 }
 267
 268 /**
 269  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 270  * @pctldev: the pin controller handling this pin
 271  * @range: applicable GPIO range
 272  * @pin: the affected GPIO pin in this controller
 273  * @input: true if we set the pin as input, false for output
 274  */
 275 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 276                           struct pinctrl_gpio_range *range,
 277                           unsigned pin, bool input)
 278 {
 279         const struct pinmux_ops *ops;
 280         int ret;
 281
 282         ops = pctldev->desc->pmxops;
 283
 284         if (ops->gpio_set_direction)
 285                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 286         else
 287                 ret = 0;
 288
 289         return ret;
 290 }
 291
 292 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 293                                         const char *function)
 294 {
 295         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 296         unsigned nfuncs = ops->get_functions_count(pctldev);
 297         unsigned selector = 0;
 298
 299         /* See if this pctldev has this function */
 300         while (selector < nfuncs) {
 301                 const char *fname = ops->get_function_name(pctldev,
 302                                                            selector);
 303
 304                 if (!strcmp(function, fname))
 305                         return selector;
 306
 307                 selector++;
 308         }
 309
 310         pr_err("%s does not support function %s\n",
 311                pinctrl_dev_get_name(pctldev), function);
 312         return -EINVAL;
 313 }
 314
 315 int pinmux_map_to_setting(struct pinctrl_map const *map,
 316                           struct pinctrl_setting *setting)
 317 {
 318         struct pinctrl_dev *pctldev = setting->pctldev;
 319         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 320         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 321         char const * const *groups;
 322         unsigned num_groups;
 323         int ret;
 324         const char *group;
 325         int i;
 326         const unsigned *pins;
 327         unsigned num_pins;
 328
 329         if (!pmxops) {
 330                 dev_err(pctldev->dev, "does not support mux function\n");
 331                 return -EINVAL;
 332         }
 333
 334         ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 335         if (ret < 0) {
 336                 dev_err(pctldev->dev, "invalid function %s in map table\n",
 337                         map->data.mux.function);
 338                 return ret;
 339         }
 340         setting->data.mux.func = ret;
 341
 342         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 343                                           &groups, &num_groups);
 344         if (ret < 0) {
 345                 dev_err(pctldev->dev, "can't query groups for function %s\n",
 346                         map->data.mux.function);
 347                 return ret;
 348         }
 349         if (!num_groups) {
 350                 dev_err(pctldev->dev,
 351                         "function %s can't be selected on any group\n",
 352                         map->data.mux.function);
 353                 return -EINVAL;
 354         }
 355         if (map->data.mux.group) {
 356                 bool found = false;
 357                 group = map->data.mux.group;
 358                 for (i = 0; i < num_groups; i++) {
 359                         if (!strcmp(group, groups[i])) {
 360                                 found = true;
 361                                 break;
 362                         }
 363                 }
 364                 if (!found) {
 365                         dev_err(pctldev->dev,
 366                                 "invalid group \"%s\" for function \"%s\"\n",
 367                                 group, map->data.mux.function);
 368                         return -EINVAL;
 369                 }
 370         } else {
 371                 group = groups[0];
 372         }
 373
 374         ret = pinctrl_get_group_selector(pctldev, group);
 375         if (ret < 0) {
 376                 dev_err(pctldev->dev, "invalid group %s in map table\n",
 377                         map->data.mux.group);
 378                 return ret;
 379         }
 380         setting->data.mux.group = ret;
 381
 382         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 383                                       &num_pins);
 384         if (ret) {
 385                 dev_err(pctldev->dev,
 386                         "could not get pins for device %s group selector %d\n",
 387                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 388                         return -ENODEV;
 389         }
 390
 391         /* Try to allocate all pins in this group, one by one */
 392         for (i = 0; i < num_pins; i++) {
 393                 ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
 394                 if (ret) {
 395                         dev_err(pctldev->dev,
 396                                 "could not request pin %d on device %s\n",
 397                                 pins[i], pinctrl_dev_get_name(pctldev));
 398                         /* On error release all taken pins */
 399                         i--; /* this pin just failed */
 400                         for (; i >= 0; i--)
 401                                 pin_free(pctldev, pins[i], NULL);
 402                         return -ENODEV;
 403                 }
 404         }
 405
 406         return 0;
 407 }
 408
 409 void pinmux_free_setting(struct pinctrl_setting const *setting)
 410 {
 411         struct pinctrl_dev *pctldev = setting->pctldev;
 412         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 413         const unsigned *pins;
 414         unsigned num_pins;
 415         int ret;
 416         int i;
 417
 418         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 419                                       &pins, &num_pins);
 420         if (ret) {
 421                 dev_err(pctldev->dev,
 422                         "could not get pins for device %s group selector %d\n",
 423                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 424                 return;
 425         }
 426
 427         for (i = 0; i < num_pins; i++)
 428                 pin_free(pctldev, pins[i], NULL);
 429 }
 430
 431 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 432 {
 433         struct pinctrl_dev *pctldev = setting->pctldev;
 434         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 435         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 436         int ret;
 437         const unsigned *pins;
 438         unsigned num_pins;
 439         int i;
 440         struct pin_desc *desc;
 441
 442         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 443                                       &pins, &num_pins);
 444         if (ret) {
 445                 /* errors only affect debug data, so just warn */
 446                 dev_warn(pctldev->dev,
 447                          "could not get pins for group selector %d\n",
 448                          setting->data.mux.group);
 449                 num_pins = 0;
 450         }
 451
 452         for (i = 0; i < num_pins; i++) {
 453                 desc = pin_desc_get(pctldev, pins[i]);
 454                 if (desc == NULL) {
 455                         dev_warn(pctldev->dev,
 456                                  "could not get pin desc for pin %d\n",
 457                                  pins[i]);
 458                         continue;
 459                 }
 460                 desc->mux_setting = &(setting->data.mux);
 461         }
 462
 463         return ops->enable(pctldev, setting->data.mux.func,
 464                            setting->data.mux.group);
 465 }
 466
 467 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 468 {
 469         struct pinctrl_dev *pctldev = setting->pctldev;
 470         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 471         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 472         int ret;
 473         const unsigned *pins;
 474         unsigned num_pins;
 475         int i;
 476         struct pin_desc *desc;
 477
 478         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 479                                       &pins, &num_pins);
 480         if (ret) {
 481                 /* errors only affect debug data, so just warn */
 482                 dev_warn(pctldev->dev,
 483                          "could not get pins for group selector %d\n",
 484                          setting->data.mux.group);
 485                 num_pins = 0;
 486         }
 487
 488         for (i = 0; i < num_pins; i++) {
 489                 desc = pin_desc_get(pctldev, pins[i]);
 490                 if (desc == NULL) {
 491                         dev_warn(pctldev->dev,
 492                                  "could not get pin desc for pin %d\n",
 493                                  pins[i]);
 494                         continue;
 495                 }
 496                 desc->mux_setting = NULL;
 497         }
 498
 499         if (ops->disable)
 500                 ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 501 }
 502
 503 #ifdef CONFIG_DEBUG_FS
 504
 505 /* Called from pincontrol core */
 506 static int pinmux_functions_show(struct seq_file *s, void *what)
 507 {
 508         struct pinctrl_dev *pctldev = s->private;
 509         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 510         unsigned nfuncs;
 511         unsigned func_selector = 0;
 512
 513         if (!pmxops)
 514                 return 0;
 515
 516         mutex_lock(&pinctrl_mutex);
 517         nfuncs = pmxops->get_functions_count(pctldev);
 518         while (func_selector < nfuncs) {
 519                 const char *func = pmxops->get_function_name(pctldev,
 520                                                           func_selector);
 521                 const char * const *groups;
 522                 unsigned num_groups;
 523                 int ret;
 524                 int i;
 525
 526                 ret = pmxops->get_function_groups(pctldev, func_selector,
 527                                                   &groups, &num_groups);
 528                 if (ret)
 529                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 530                                    func);
 531
 532                 seq_printf(s, "function: %s, groups = [ ", func);
 533                 for (i = 0; i < num_groups; i++)
 534                         seq_printf(s, "%s ", groups[i]);
 535                 seq_puts(s, "]\n");
 536
 537                 func_selector++;
 538         }
 539
 540         mutex_unlock(&pinctrl_mutex);
 541
 542         return 0;
 543 }
 544
 545 static int pinmux_pins_show(struct seq_file *s, void *what)
 546 {
 547         struct pinctrl_dev *pctldev = s->private;
 548         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 549         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 550         unsigned i, pin;
 551
 552         if (!pmxops)
 553                 return 0;
 554
 555         seq_puts(s, "Pinmux settings per pin\n");
 556         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 557
 558         mutex_lock(&pinctrl_mutex);
 559
 560         /* The pin number can be retrived from the pin controller descriptor */
 561         for (i = 0; i < pctldev->desc->npins; i++) {
 562                 struct pin_desc *desc;
 563                 bool is_hog = false;
 564
 565                 pin = pctldev->desc->pins[i].number;
 566                 desc = pin_desc_get(pctldev, pin);
 567                 /* Skip if we cannot search the pin */
 568                 if (desc == NULL)
 569                         continue;
 570
 571                 if (desc->mux_owner &&
 572                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 573                         is_hog = true;
 574
 575                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 576                            desc->name ? desc->name : "unnamed",
 577                            desc->mux_owner ? desc->mux_owner
 578                                 : "(MUX UNCLAIMED)",
 579                            desc->gpio_owner ? desc->gpio_owner
 580                                 : "(GPIO UNCLAIMED)",
 581                            is_hog ? " (HOG)" : "");
 582
 583                 if (desc->mux_setting)
 584                         seq_printf(s, " function %s group %s\n",
 585                                    pmxops->get_function_name(pctldev,
 586                                         desc->mux_setting->func),
 587                                    pctlops->get_group_name(pctldev,
 588                                         desc->mux_setting->group));
 589                 else
 590                         seq_printf(s, "\n");
 591         }
 592
 593         mutex_unlock(&pinctrl_mutex);
 594
 595         return 0;
 596 }
 597
 598 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 599 {
 600         seq_printf(s, "group %s\nfunction %s\n",
 601                 map->data.mux.group ? map->data.mux.group : "(default)",
 602                 map->data.mux.function);
 603 }
 604
 605 void pinmux_show_setting(struct seq_file *s,
 606                          struct pinctrl_setting const *setting)
 607 {
 608         struct pinctrl_dev *pctldev = setting->pctldev;
 609         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 610         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 611
 612         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 613                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 614                    setting->data.mux.group,
 615                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 616                    setting->data.mux.func);
 617 }
 618
 619 static int pinmux_functions_open(struct inode *inode, struct file *file)
 620 {
 621         return single_open(file, pinmux_functions_show, inode->i_private);
 622 }
 623
 624 static int pinmux_pins_open(struct inode *inode, struct file *file)
 625 {
 626         return single_open(file, pinmux_pins_show, inode->i_private);
 627 }
 628
 629 static const struct file_operations pinmux_functions_ops = {
 630         .open           = pinmux_functions_open,
 631         .read           = seq_read,
 632         .llseek         = seq_lseek,
 633         .release        = single_release,
 634 };
 635
 636 static const struct file_operations pinmux_pins_ops = {
 637         .open           = pinmux_pins_open,
 638         .read           = seq_read,
 639         .llseek         = seq_lseek,
 640         .release        = single_release,
 641 };
 642
 643 void pinmux_init_device_debugfs(struct dentry *devroot,
 644                          struct pinctrl_dev *pctldev)
 645 {
 646         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 647                             devroot, pctldev, &pinmux_functions_ops);
 648         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 649                             devroot, pctldev, &pinmux_pins_ops);
 650 }
 651
 652 #endif /* CONFIG_DEBUG_FS */