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                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 */
 231int 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 */
 256void 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 */
 272int 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
 289static 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
 312int 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
 406void 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
 428int 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
 464void 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 */
 503static 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
 542static 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
 595void 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
 602void 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
 616static int pinmux_functions_open(struct inode *inode, struct file *file)
 617{
 618        return single_open(file, pinmux_functions_show, inode->i_private);
 619}
 620
 621static int pinmux_pins_open(struct inode *inode, struct file *file)
 622{
 623        return single_open(file, pinmux_pins_show, inode->i_private);
 624}
 625
 626static 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
 633static 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
 640void 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 */
 650
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