linux/drivers/pinctrl/pinmux.c
<<
>>
Prefs
   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
  33int 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
  64int 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 */
  83static 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
 153out_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        }
 163out:
 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 */
 182static 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 */
 236int 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 */
 261void 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 */
 277int 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
 294static 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
 317int 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
 384void pinmux_free_setting(struct pinctrl_setting const *setting)
 385{
 386        /* This function is currently unused */
 387}
 388
 389int 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;
 395        const unsigned *pins;
 396        unsigned num_pins;
 397        int i;
 398        struct pin_desc *desc;
 399
 400        ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 401                                      &pins, &num_pins);
 402        if (ret) {
 403                const char *gname;
 404
 405                /* errors only affect debug data, so just warn */
 406                gname = pctlops->get_group_name(pctldev,
 407                                                setting->data.mux.group);
 408                dev_warn(pctldev->dev,
 409                         "could not get pins for group %s\n",
 410                         gname);
 411                num_pins = 0;
 412        }
 413
 414        /* Try to allocate all pins in this group, one by one */
 415        for (i = 0; i < num_pins; i++) {
 416                ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
 417                if (ret) {
 418                        const char *gname;
 419                        const char *pname;
 420
 421                        desc = pin_desc_get(pctldev, pins[i]);
 422                        pname = desc ? desc->name : "non-existing";
 423                        gname = pctlops->get_group_name(pctldev,
 424                                                setting->data.mux.group);
 425                        dev_err(pctldev->dev,
 426                                "could not request pin %d (%s) from group %s "
 427                                " on device %s\n",
 428                                pins[i], pname, gname,
 429                                pinctrl_dev_get_name(pctldev));
 430                        goto err_pin_request;
 431                }
 432        }
 433
 434        /* Now that we have acquired the pins, encode the mux setting */
 435        for (i = 0; i < num_pins; i++) {
 436                desc = pin_desc_get(pctldev, pins[i]);
 437                if (desc == NULL) {
 438                        dev_warn(pctldev->dev,
 439                                 "could not get pin desc for pin %d\n",
 440                                 pins[i]);
 441                        continue;
 442                }
 443                desc->mux_setting = &(setting->data.mux);
 444        }
 445
 446        ret = ops->enable(pctldev, setting->data.mux.func,
 447                          setting->data.mux.group);
 448
 449        if (ret)
 450                goto err_enable;
 451
 452        return 0;
 453
 454err_enable:
 455        for (i = 0; i < num_pins; i++) {
 456                desc = pin_desc_get(pctldev, pins[i]);
 457                if (desc)
 458                        desc->mux_setting = NULL;
 459        }
 460err_pin_request:
 461        /* On error release all taken pins */
 462        while (--i >= 0)
 463                pin_free(pctldev, pins[i], NULL);
 464
 465        return ret;
 466}
 467
 468void pinmux_disable_setting(struct pinctrl_setting const *setting)
 469{
 470        struct pinctrl_dev *pctldev = setting->pctldev;
 471        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 472        const struct pinmux_ops *ops = pctldev->desc->pmxops;
 473        int ret;
 474        const unsigned *pins;
 475        unsigned num_pins;
 476        int i;
 477        struct pin_desc *desc;
 478
 479        ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 480                                      &pins, &num_pins);
 481        if (ret) {
 482                const char *gname;
 483
 484                /* errors only affect debug data, so just warn */
 485                gname = pctlops->get_group_name(pctldev,
 486                                                setting->data.mux.group);
 487                dev_warn(pctldev->dev,
 488                         "could not get pins for group %s\n",
 489                         gname);
 490                num_pins = 0;
 491        }
 492
 493        /* Flag the descs that no setting is active */
 494        for (i = 0; i < num_pins; i++) {
 495                desc = pin_desc_get(pctldev, pins[i]);
 496                if (desc == NULL) {
 497                        dev_warn(pctldev->dev,
 498                                 "could not get pin desc for pin %d\n",
 499                                 pins[i]);
 500                        continue;
 501                }
 502                if (desc->mux_setting == &(setting->data.mux)) {
 503                        desc->mux_setting = NULL;
 504                        /* And release the pin */
 505                        pin_free(pctldev, pins[i], NULL);
 506                } else {
 507                        const char *gname;
 508                        const char *pname;
 509
 510                        pname = desc ? desc->name : "non-existing";
 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], pname, gname);
 518                }
 519        }
 520
 521        if (ops->disable)
 522                ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 523}
 524
 525#ifdef CONFIG_DEBUG_FS
 526
 527/* Called from pincontrol core */
 528static int pinmux_functions_show(struct seq_file *s, void *what)
 529{
 530        struct pinctrl_dev *pctldev = s->private;
 531        const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 532        unsigned nfuncs;
 533        unsigned func_selector = 0;
 534
 535        if (!pmxops)
 536                return 0;
 537
 538        mutex_lock(&pctldev->mutex);
 539        nfuncs = pmxops->get_functions_count(pctldev);
 540        while (func_selector < nfuncs) {
 541                const char *func = pmxops->get_function_name(pctldev,
 542                                                          func_selector);
 543                const char * const *groups;
 544                unsigned num_groups;
 545                int ret;
 546                int i;
 547
 548                ret = pmxops->get_function_groups(pctldev, func_selector,
 549                                                  &groups, &num_groups);
 550                if (ret)
 551                        seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 552                                   func);
 553
 554                seq_printf(s, "function: %s, groups = [ ", func);
 555                for (i = 0; i < num_groups; i++)
 556                        seq_printf(s, "%s ", groups[i]);
 557                seq_puts(s, "]\n");
 558
 559                func_selector++;
 560        }
 561
 562        mutex_unlock(&pctldev->mutex);
 563
 564        return 0;
 565}
 566
 567static int pinmux_pins_show(struct seq_file *s, void *what)
 568{
 569        struct pinctrl_dev *pctldev = s->private;
 570        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 571        const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 572        unsigned i, pin;
 573
 574        if (!pmxops)
 575                return 0;
 576
 577        seq_puts(s, "Pinmux settings per pin\n");
 578        seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 579
 580        mutex_lock(&pctldev->mutex);
 581
 582        /* The pin number can be retrived from the pin controller descriptor */
 583        for (i = 0; i < pctldev->desc->npins; i++) {
 584                struct pin_desc *desc;
 585                bool is_hog = false;
 586
 587                pin = pctldev->desc->pins[i].number;
 588                desc = pin_desc_get(pctldev, pin);
 589                /* Skip if we cannot search the pin */
 590                if (desc == NULL)
 591                        continue;
 592
 593                if (desc->mux_owner &&
 594                    !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 595                        is_hog = true;
 596
 597                seq_printf(s, "pin %d (%s): %s %s%s", pin,
 598                           desc->name ? desc->name : "unnamed",
 599                           desc->mux_owner ? desc->mux_owner
 600                                : "(MUX UNCLAIMED)",
 601                           desc->gpio_owner ? desc->gpio_owner
 602                                : "(GPIO UNCLAIMED)",
 603                           is_hog ? " (HOG)" : "");
 604
 605                if (desc->mux_setting)
 606                        seq_printf(s, " function %s group %s\n",
 607                                   pmxops->get_function_name(pctldev,
 608                                        desc->mux_setting->func),
 609                                   pctlops->get_group_name(pctldev,
 610                                        desc->mux_setting->group));
 611                else
 612                        seq_printf(s, "\n");
 613        }
 614
 615        mutex_unlock(&pctldev->mutex);
 616
 617        return 0;
 618}
 619
 620void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 621{
 622        seq_printf(s, "group %s\nfunction %s\n",
 623                map->data.mux.group ? map->data.mux.group : "(default)",
 624                map->data.mux.function);
 625}
 626
 627void pinmux_show_setting(struct seq_file *s,
 628                         struct pinctrl_setting const *setting)
 629{
 630        struct pinctrl_dev *pctldev = setting->pctldev;
 631        const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 632        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 633
 634        seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 635                   pctlops->get_group_name(pctldev, setting->data.mux.group),
 636                   setting->data.mux.group,
 637                   pmxops->get_function_name(pctldev, setting->data.mux.func),
 638                   setting->data.mux.func);
 639}
 640
 641static int pinmux_functions_open(struct inode *inode, struct file *file)
 642{
 643        return single_open(file, pinmux_functions_show, inode->i_private);
 644}
 645
 646static int pinmux_pins_open(struct inode *inode, struct file *file)
 647{
 648        return single_open(file, pinmux_pins_show, inode->i_private);
 649}
 650
 651static const struct file_operations pinmux_functions_ops = {
 652        .open           = pinmux_functions_open,
 653        .read           = seq_read,
 654        .llseek         = seq_lseek,
 655        .release        = single_release,
 656};
 657
 658static const struct file_operations pinmux_pins_ops = {
 659        .open           = pinmux_pins_open,
 660        .read           = seq_read,
 661        .llseek         = seq_lseek,
 662        .release        = single_release,
 663};
 664
 665void pinmux_init_device_debugfs(struct dentry *devroot,
 666                         struct pinctrl_dev *pctldev)
 667{
 668        debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 669                            devroot, pctldev, &pinmux_functions_ops);
 670        debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 671                            devroot, pctldev, &pinmux_pins_ops);
 672}
 673
 674#endif /* CONFIG_DEBUG_FS */
 675
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.