drivers/pinctrl/pinmux.c

   1 /*
   2  * Core driver for the pin muxing portions of the pin control subsystem
   3  *
   4  * Copyright (C) 2011-2012 ST-Ericsson SA
   5  * Written on behalf of Linaro for ST-Ericsson
   6  * Based on bits of regulator core, gpio core and clk core
   7  *
   8  * Author: Linus Walleij <linus.walleij@linaro.org>
   9  *
  10  * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
  11  *
  12  * License terms: GNU General Public License (GPL) version 2
  13  */
  14 #define pr_fmt(fmt) "pinmux core: " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/device.h>
  20 #include <linux/slab.h>
  21 #include <linux/radix-tree.h>
  22 #include <linux/err.h>
  23 #include <linux/list.h>
  24 #include <linux/string.h>
  25 #include <linux/sysfs.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/pinctrl/machine.h>
  29 #include <linux/pinctrl/pinmux.h>
  30 #include "core.h"
  31 #include "pinmux.h"
  32
  33 int pinmux_check_ops(struct pinctrl_dev *pctldev)
  34 {
  35         const struct pinmux_ops *ops = pctldev->desc->pmxops;
  36         unsigned selector = 0;
  37
  38         /* Check that we implement required operations */
  39         if (!ops->list_functions ||
  40             !ops->get_function_name ||
  41             !ops->get_function_groups ||
  42             !ops->enable ||
  43             !ops->disable)
  44                 return -EINVAL;
  45
  46         /* Check that all functions registered have names */
  47         while (ops->list_functions(pctldev, selector) >= 0) {
  48                 const char *fname = ops->get_function_name(pctldev,
  49                                                            selector);
  50                 if (!fname) {
  51                         pr_err("pinmux ops has no name for function%u\n",
  52                                 selector);
  53                         return -EINVAL;
  54                 }
  55                 selector++;
  56         }
  57
  58         return 0;
  59 }
  60
  61 int pinmux_validate_map(struct pinctrl_map const *map, int i)
  62 {
  63         if (!map->data.mux.function) {
  64                 pr_err("failed to register map %s (%d): no function given\n",
  65                        map->name, i);
  66                 return -EINVAL;
  67         }
  68
  69         return 0;
  70 }
  71
  72 /**
  73  * pin_request() - request a single pin to be muxed in, typically for GPIO
  74  * @pin: the pin number in the global pin space
  75  * @owner: a representation of the owner of this pin; typically the device
  76  *      name that controls its mux function, or the requested GPIO name
  77  * @gpio_range: the range matching the GPIO pin if this is a request for a
  78  *      single GPIO pin
  79  */
  80 static int pin_request(struct pinctrl_dev *pctldev,
  81                        int pin, const char *owner,
  82                        struct pinctrl_gpio_range *gpio_range)
  83 {
  84         struct pin_desc *desc;
  85         const struct pinmux_ops *ops = pctldev->desc->pmxops;
  86         int status = -EINVAL;
  87
  88         dev_dbg(pctldev->dev, "request pin %d for %s\n", pin, owner);
  89
  90         desc = pin_desc_get(pctldev, pin);
  91         if (desc == NULL) {
  92                 dev_err(pctldev->dev,
  93                         "pin is not registered so it cannot be requested\n");
  94                 goto out;
  95         }
  96
  97         if (gpio_range) {
  98                 /* There's no need to support multiple GPIO requests */
  99                 if (desc->gpio_owner) {
 100                         dev_err(pctldev->dev,
 101                                 "pin already requested\n");
 102                         goto out;
 103                 }
 104
 105                 desc->gpio_owner = owner;
 106         } else {
 107                 if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
 108                         dev_err(pctldev->dev,
 109                                 "pin already requested\n");
 110                         goto out;
 111                 }
 112
 113                 desc->mux_usecount++;
 114                 if (desc->mux_usecount > 1)
 115                         return 0;
 116
 117                 desc->mux_owner = owner;
 118         }
 119
 120         /* Let each pin increase references to this module */
 121         if (!try_module_get(pctldev->owner)) {
 122                 dev_err(pctldev->dev,
 123                         "could not increase module refcount for pin %d\n",
 124                         pin);
 125                 status = -EINVAL;
 126                 goto out_free_pin;
 127         }
 128
 129         /*
 130          * If there is no kind of request function for the pin we just assume
 131          * we got it by default and proceed.
 132          */
 133         if (gpio_range && ops->gpio_request_enable)
 134                 /* This requests and enables a single GPIO pin */
 135                 status = ops->gpio_request_enable(pctldev, gpio_range, pin);
 136         else if (ops->request)
 137                 status = ops->request(pctldev, pin);
 138         else
 139                 status = 0;
 140
 141         if (status) {
 142                 dev_err(pctldev->dev, "->request on device %s failed for pin %d\n",
 143                        pctldev->desc->name, pin);
 144                 module_put(pctldev->owner);
 145         }
 146
 147 out_free_pin:
 148         if (status) {
 149                 if (gpio_range) {
 150                         desc->gpio_owner = NULL;
 151                 } else {
 152                         desc->mux_usecount--;
 153                         if (!desc->mux_usecount)
 154                                 desc->mux_owner = NULL;
 155                 }
 156         }
 157 out:
 158         if (status)
 159                 dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
 160                        pin, owner, status);
 161
 162         return status;
 163 }
 164
 165 /**
 166  * pin_free() - release a single muxed in pin so something else can be muxed
 167  * @pctldev: pin controller device handling this pin
 168  * @pin: the pin to free
 169  * @gpio_range: the range matching the GPIO pin if this is a request for a
 170  *      single GPIO pin
 171  *
 172  * This function returns a pointer to the previous owner. This is used
 173  * for callers that dynamically allocate an owner name so it can be freed
 174  * once the pin is free. This is done for GPIO request functions.
 175  */
 176 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 177                             struct pinctrl_gpio_range *gpio_range)
 178 {
 179         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 180         struct pin_desc *desc;
 181         const char *owner;
 182
 183         desc = pin_desc_get(pctldev, pin);
 184         if (desc == NULL) {
 185                 dev_err(pctldev->dev,
 186                         "pin is not registered so it cannot be freed\n");
 187                 return NULL;
 188         }
 189
 190         if (!gpio_range) {
 191                 desc->mux_usecount--;
 192                 if (desc->mux_usecount)
 193                         return NULL;
 194         }
 195
 196         /*
 197          * If there is no kind of request function for the pin we just assume
 198          * we got it by default and proceed.
 199          */
 200         if (gpio_range && ops->gpio_disable_free)
 201                 ops->gpio_disable_free(pctldev, gpio_range, pin);
 202         else if (ops->free)
 203                 ops->free(pctldev, pin);
 204
 205         if (gpio_range) {
 206                 owner = desc->gpio_owner;
 207                 desc->gpio_owner = NULL;
 208         } else {
 209                 owner = desc->mux_owner;
 210                 desc->mux_owner = NULL;
 211                 desc->mux_setting = NULL;
 212         }
 213
 214         module_put(pctldev->owner);
 215
 216         return owner;
 217 }
 218
 219 /**
 220  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 221  * @pctldev: pin controller device affected
 222  * @pin: the pin to mux in for GPIO
 223  * @range: the applicable GPIO range
 224  */
 225 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 226                         struct pinctrl_gpio_range *range,
 227                         unsigned pin, unsigned gpio)
 228 {
 229         char gpiostr[16];
 230         const char *owner;
 231         int ret;
 232
 233         /* Conjure some name stating what chip and pin this is taken by */
 234         snprintf(gpiostr, 15, "%s:%d", range->name, gpio);
 235
 236         owner = kstrdup(gpiostr, GFP_KERNEL);
 237         if (!owner)
 238                 return -EINVAL;
 239
 240         ret = pin_request(pctldev, pin, owner, range);
 241         if (ret < 0)
 242                 kfree(owner);
 243
 244         return ret;
 245 }
 246
 247 /**
 248  * pinmux_free_gpio() - release a pin from GPIO muxing
 249  * @pctldev: the pin controller device for the pin
 250  * @pin: the affected currently GPIO-muxed in pin
 251  * @range: applicable GPIO range
 252  */
 253 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 254                       struct pinctrl_gpio_range *range)
 255 {
 256         const char *owner;
 257
 258         owner = pin_free(pctldev, pin, range);
 259         kfree(owner);
 260 }
 261
 262 /**
 263  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 264  * @pctldev: the pin controller handling this pin
 265  * @range: applicable GPIO range
 266  * @pin: the affected GPIO pin in this controller
 267  * @input: true if we set the pin as input, false for output
 268  */
 269 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 270                           struct pinctrl_gpio_range *range,
 271                           unsigned pin, bool input)
 272 {
 273         const struct pinmux_ops *ops;
 274         int ret;
 275
 276         ops = pctldev->desc->pmxops;
 277
 278         if (ops->gpio_set_direction)
 279                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 280         else
 281                 ret = 0;
 282
 283         return ret;
 284 }
 285
 286 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 287                                         const char *function)
 288 {
 289         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 290         unsigned selector = 0;
 291
 292         /* See if this pctldev has this function */
 293         while (ops->list_functions(pctldev, selector) >= 0) {
 294                 const char *fname = ops->get_function_name(pctldev,
 295                                                            selector);
 296
 297                 if (!strcmp(function, fname))
 298                         return selector;
 299
 300                 selector++;
 301         }
 302
 303         pr_err("%s does not support function %s\n",
 304                pinctrl_dev_get_name(pctldev), function);
 305         return -EINVAL;
 306 }
 307
 308 int pinmux_map_to_setting(struct pinctrl_map const *map,
 309                           struct pinctrl_setting *setting)
 310 {
 311         struct pinctrl_dev *pctldev = setting->pctldev;
 312         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 313         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 314         char const * const *groups;
 315         unsigned num_groups;
 316         int ret;
 317         const char *group;
 318         int i;
 319         const unsigned *pins;
 320         unsigned num_pins;
 321
 322         setting->data.mux.func =
 323                 pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 324         if (setting->data.mux.func < 0)
 325                 return setting->data.mux.func;
 326
 327         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 328                                           &groups, &num_groups);
 329         if (ret < 0)
 330                 return ret;
 331         if (!num_groups)
 332                 return -EINVAL;
 333
 334         if (map->data.mux.group) {
 335                 bool found = false;
 336                 group = map->data.mux.group;
 337                 for (i = 0; i < num_groups; i++) {
 338                         if (!strcmp(group, groups[i])) {
 339                                 found = true;
 340                                 break;
 341                         }
 342                 }
 343                 if (!found)
 344                         return -EINVAL;
 345         } else {
 346                 group = groups[0];
 347         }
 348
 349         setting->data.mux.group = pinctrl_get_group_selector(pctldev, group);
 350         if (setting->data.mux.group < 0)
 351                 return setting->data.mux.group;
 352
 353         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 354                                       &num_pins);
 355         if (ret) {
 356                 dev_err(pctldev->dev,
 357                         "could not get pins for device %s group selector %d\n",
 358                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 359                         return -ENODEV;
 360         }
 361
 362         /* Try to allocate all pins in this group, one by one */
 363         for (i = 0; i < num_pins; i++) {
 364                 ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
 365                 if (ret) {
 366                         dev_err(pctldev->dev,
 367                                 "could not get request pin %d on device %s\n",
 368                                 pins[i], pinctrl_dev_get_name(pctldev));
 369                         /* On error release all taken pins */
 370                         i--; /* this pin just failed */
 371                         for (; i >= 0; i--)
 372                                 pin_free(pctldev, pins[i], NULL);
 373                         return -ENODEV;
 374                 }
 375         }
 376
 377         return 0;
 378 }
 379
 380 void pinmux_free_setting(struct pinctrl_setting const *setting)
 381 {
 382         struct pinctrl_dev *pctldev = setting->pctldev;
 383         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 384         const unsigned *pins;
 385         unsigned num_pins;
 386         int ret;
 387         int i;
 388
 389         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 390                                       &pins, &num_pins);
 391         if (ret) {
 392                 dev_err(pctldev->dev,
 393                         "could not get pins for device %s group selector %d\n",
 394                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 395                 return;
 396         }
 397
 398         for (i = 0; i < num_pins; i++)
 399                 pin_free(pctldev, pins[i], NULL);
 400 }
 401
 402 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 403 {
 404         struct pinctrl_dev *pctldev = setting->pctldev;
 405         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 406         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 407         int ret;
 408         const unsigned *pins;
 409         unsigned num_pins;
 410         int i;
 411         struct pin_desc *desc;
 412
 413         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 414                                       &pins, &num_pins);
 415         if (ret) {
 416                 /* errors only affect debug data, so just warn */
 417                 dev_warn(pctldev->dev,
 418                          "could not get pins for group selector %d\n",
 419                          setting->data.mux.group);
 420                 num_pins = 0;
 421         }
 422
 423         for (i = 0; i < num_pins; i++) {
 424                 desc = pin_desc_get(pctldev, pins[i]);
 425                 if (desc == NULL) {
 426                         dev_warn(pctldev->dev,
 427                                  "could not get pin desc for pin %d\n",
 428                                  pins[i]);
 429                         continue;
 430                 }
 431                 desc->mux_setting = &(setting->data.mux);
 432         }
 433
 434         return ops->enable(pctldev, setting->data.mux.func,
 435                            setting->data.mux.group);
 436 }
 437
 438 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 439 {
 440         struct pinctrl_dev *pctldev = setting->pctldev;
 441         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 442         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 443         int ret;
 444         const unsigned *pins;
 445         unsigned num_pins;
 446         int i;
 447         struct pin_desc *desc;
 448
 449         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 450                                       &pins, &num_pins);
 451         if (ret) {
 452                 /* errors only affect debug data, so just warn */
 453                 dev_warn(pctldev->dev,
 454                          "could not get pins for group selector %d\n",
 455                          setting->data.mux.group);
 456                 num_pins = 0;
 457         }
 458
 459         for (i = 0; i < num_pins; i++) {
 460                 desc = pin_desc_get(pctldev, pins[i]);
 461                 if (desc == NULL) {
 462                         dev_warn(pctldev->dev,
 463                                  "could not get pin desc for pin %d\n",
 464                                  pins[i]);
 465                         continue;
 466                 }
 467                 desc->mux_setting = NULL;
 468         }
 469
 470         ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 471 }
 472
 473 #ifdef CONFIG_DEBUG_FS
 474
 475 /* Called from pincontrol core */
 476 static int pinmux_functions_show(struct seq_file *s, void *what)
 477 {
 478         struct pinctrl_dev *pctldev = s->private;
 479         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 480         unsigned func_selector = 0;
 481
 482         mutex_lock(&pinctrl_mutex);
 483
 484         while (pmxops->list_functions(pctldev, func_selector) >= 0) {
 485                 const char *func = pmxops->get_function_name(pctldev,
 486                                                           func_selector);
 487                 const char * const *groups;
 488                 unsigned num_groups;
 489                 int ret;
 490                 int i;
 491
 492                 ret = pmxops->get_function_groups(pctldev, func_selector,
 493                                                   &groups, &num_groups);
 494                 if (ret)
 495                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 496                                    func);
 497
 498                 seq_printf(s, "function: %s, groups = [ ", func);
 499                 for (i = 0; i < num_groups; i++)
 500                         seq_printf(s, "%s ", groups[i]);
 501                 seq_puts(s, "]\n");
 502
 503                 func_selector++;
 504         }
 505
 506         mutex_unlock(&pinctrl_mutex);
 507
 508         return 0;
 509 }
 510
 511 static int pinmux_pins_show(struct seq_file *s, void *what)
 512 {
 513         struct pinctrl_dev *pctldev = s->private;
 514         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 515         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 516         unsigned i, pin;
 517
 518         seq_puts(s, "Pinmux settings per pin\n");
 519         seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
 520
 521         mutex_lock(&pinctrl_mutex);
 522
 523         /* The pin number can be retrived from the pin controller descriptor */
 524         for (i = 0; i < pctldev->desc->npins; i++) {
 525                 struct pin_desc *desc;
 526                 bool is_hog = false;
 527
 528                 pin = pctldev->desc->pins[i].number;
 529                 desc = pin_desc_get(pctldev, pin);
 530                 /* Skip if we cannot search the pin */
 531                 if (desc == NULL)
 532                         continue;
 533
 534                 if (desc->mux_owner &&
 535                     !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
 536                         is_hog = true;
 537
 538                 seq_printf(s, "pin %d (%s): %s %s%s", pin,
 539                            desc->name ? desc->name : "unnamed",
 540                            desc->mux_owner ? desc->mux_owner
 541                                 : "(MUX UNCLAIMED)",
 542                            desc->gpio_owner ? desc->gpio_owner
 543                                 : "(GPIO UNCLAIMED)",
 544                            is_hog ? " (HOG)" : "");
 545
 546                 if (desc->mux_setting)
 547                         seq_printf(s, " function %s group %s\n",
 548                                    pmxops->get_function_name(pctldev,
 549                                         desc->mux_setting->func),
 550                                    pctlops->get_group_name(pctldev,
 551                                         desc->mux_setting->group));
 552                 else
 553                         seq_printf(s, "\n");
 554         }
 555
 556         mutex_unlock(&pinctrl_mutex);
 557
 558         return 0;
 559 }
 560
 561 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 562 {
 563         seq_printf(s, "group %s\nfunction %s\n",
 564                 map->data.mux.group ? map->data.mux.group : "(default)",
 565                 map->data.mux.function);
 566 }
 567
 568 void pinmux_show_setting(struct seq_file *s,
 569                          struct pinctrl_setting const *setting)
 570 {
 571         struct pinctrl_dev *pctldev = setting->pctldev;
 572         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 573         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 574
 575         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 576                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 577                    setting->data.mux.group,
 578                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 579                    setting->data.mux.func);
 580 }
 581
 582 static int pinmux_functions_open(struct inode *inode, struct file *file)
 583 {
 584         return single_open(file, pinmux_functions_show, inode->i_private);
 585 }
 586
 587 static int pinmux_pins_open(struct inode *inode, struct file *file)
 588 {
 589         return single_open(file, pinmux_pins_show, inode->i_private);
 590 }
 591
 592 static const struct file_operations pinmux_functions_ops = {
 593         .open           = pinmux_functions_open,
 594         .read           = seq_read,
 595         .llseek         = seq_lseek,
 596         .release        = single_release,
 597 };
 598
 599 static const struct file_operations pinmux_pins_ops = {
 600         .open           = pinmux_pins_open,
 601         .read           = seq_read,
 602         .llseek         = seq_lseek,
 603         .release        = single_release,
 604 };
 605
 606 void pinmux_init_device_debugfs(struct dentry *devroot,
 607                          struct pinctrl_dev *pctldev)
 608 {
 609         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 610                             devroot, pctldev, &pinmux_functions_ops);
 611         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 612                             devroot, pctldev, &pinmux_pins_ops);
 613 }
 614
 615 #endif /* CONFIG_DEBUG_FS */