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