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