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 (desc->usecount && strcmp(desc->owner, owner)) {
  98                 dev_err(pctldev->dev,
  99                         "pin already requested\n");
 100                 goto out;
 101         }
 102
 103         desc->usecount++;
 104         if (desc->usecount > 1)
 105                 return 0;
 106
 107         desc->owner = owner;
 108
 109         /* Let each pin increase references to this module */
 110         if (!try_module_get(pctldev->owner)) {
 111                 dev_err(pctldev->dev,
 112                         "could not increase module refcount for pin %d\n",
 113                         pin);
 114                 status = -EINVAL;
 115                 goto out_free_pin;
 116         }
 117
 118         /*
 119          * If there is no kind of request function for the pin we just assume
 120          * we got it by default and proceed.
 121          */
 122         if (gpio_range && ops->gpio_request_enable)
 123                 /* This requests and enables a single GPIO pin */
 124                 status = ops->gpio_request_enable(pctldev, gpio_range, pin);
 125         else if (ops->request)
 126                 status = ops->request(pctldev, pin);
 127         else
 128                 status = 0;
 129
 130         if (status) {
 131                 dev_err(pctldev->dev, "->request on device %s failed for pin %d\n",
 132                        pctldev->desc->name, pin);
 133                 module_put(pctldev->owner);
 134         }
 135
 136 out_free_pin:
 137         if (status) {
 138                 desc->usecount--;
 139                 if (!desc->usecount)
 140                         desc->owner = NULL;
 141         }
 142 out:
 143         if (status)
 144                 dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
 145                        pin, owner, status);
 146
 147         return status;
 148 }
 149
 150 /**
 151  * pin_free() - release a single muxed in pin so something else can be muxed
 152  * @pctldev: pin controller device handling this pin
 153  * @pin: the pin to free
 154  * @gpio_range: the range matching the GPIO pin if this is a request for a
 155  *      single GPIO pin
 156  *
 157  * This function returns a pointer to the previous owner. This is used
 158  * for callers that dynamically allocate an owner name so it can be freed
 159  * once the pin is free. This is done for GPIO request functions.
 160  */
 161 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 162                             struct pinctrl_gpio_range *gpio_range)
 163 {
 164         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 165         struct pin_desc *desc;
 166         const char *owner;
 167
 168         desc = pin_desc_get(pctldev, pin);
 169         if (desc == NULL) {
 170                 dev_err(pctldev->dev,
 171                         "pin is not registered so it cannot be freed\n");
 172                 return NULL;
 173         }
 174
 175         desc->usecount--;
 176         if (desc->usecount)
 177                 return NULL;
 178
 179         /*
 180          * If there is no kind of request function for the pin we just assume
 181          * we got it by default and proceed.
 182          */
 183         if (gpio_range && ops->gpio_disable_free)
 184                 ops->gpio_disable_free(pctldev, gpio_range, pin);
 185         else if (ops->free)
 186                 ops->free(pctldev, pin);
 187
 188         owner = desc->owner;
 189         desc->owner = NULL;
 190         module_put(pctldev->owner);
 191
 192         return owner;
 193 }
 194
 195 /**
 196  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 197  * @pctldev: pin controller device affected
 198  * @pin: the pin to mux in for GPIO
 199  * @range: the applicable GPIO range
 200  */
 201 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 202                         struct pinctrl_gpio_range *range,
 203                         unsigned pin, unsigned gpio)
 204 {
 205         char gpiostr[16];
 206         const char *owner;
 207         int ret;
 208
 209         /* Conjure some name stating what chip and pin this is taken by */
 210         snprintf(gpiostr, 15, "%s:%d", range->name, gpio);
 211
 212         owner = kstrdup(gpiostr, GFP_KERNEL);
 213         if (!owner)
 214                 return -EINVAL;
 215
 216         ret = pin_request(pctldev, pin, owner, range);
 217         if (ret < 0)
 218                 kfree(owner);
 219
 220         return ret;
 221 }
 222
 223 /**
 224  * pinmux_free_gpio() - release a pin from GPIO muxing
 225  * @pctldev: the pin controller device for the pin
 226  * @pin: the affected currently GPIO-muxed in pin
 227  * @range: applicable GPIO range
 228  */
 229 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
 230                       struct pinctrl_gpio_range *range)
 231 {
 232         const char *owner;
 233
 234         owner = pin_free(pctldev, pin, range);
 235         kfree(owner);
 236 }
 237
 238 /**
 239  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 240  * @pctldev: the pin controller handling this pin
 241  * @range: applicable GPIO range
 242  * @pin: the affected GPIO pin in this controller
 243  * @input: true if we set the pin as input, false for output
 244  */
 245 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 246                           struct pinctrl_gpio_range *range,
 247                           unsigned pin, bool input)
 248 {
 249         const struct pinmux_ops *ops;
 250         int ret;
 251
 252         ops = pctldev->desc->pmxops;
 253
 254         if (ops->gpio_set_direction)
 255                 ret = ops->gpio_set_direction(pctldev, range, pin, input);
 256         else
 257                 ret = 0;
 258
 259         return ret;
 260 }
 261
 262 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 263                                         const char *function)
 264 {
 265         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 266         unsigned selector = 0;
 267
 268         /* See if this pctldev has this function */
 269         while (ops->list_functions(pctldev, selector) >= 0) {
 270                 const char *fname = ops->get_function_name(pctldev,
 271                                                            selector);
 272
 273                 if (!strcmp(function, fname))
 274                         return selector;
 275
 276                 selector++;
 277         }
 278
 279         pr_err("%s does not support function %s\n",
 280                pinctrl_dev_get_name(pctldev), function);
 281         return -EINVAL;
 282 }
 283
 284 int pinmux_map_to_setting(struct pinctrl_map const *map,
 285                           struct pinctrl_setting *setting)
 286 {
 287         struct pinctrl_dev *pctldev = setting->pctldev;
 288         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 289         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 290         char const * const *groups;
 291         unsigned num_groups;
 292         int ret;
 293         const char *group;
 294         int i;
 295         const unsigned *pins;
 296         unsigned num_pins;
 297
 298         setting->data.mux.func =
 299                 pinmux_func_name_to_selector(pctldev, map->data.mux.function);
 300         if (setting->data.mux.func < 0)
 301                 return setting->data.mux.func;
 302
 303         ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 304                                           &groups, &num_groups);
 305         if (ret < 0)
 306                 return ret;
 307         if (!num_groups)
 308                 return -EINVAL;
 309
 310         if (map->data.mux.group) {
 311                 bool found = false;
 312                 group = map->data.mux.group;
 313                 for (i = 0; i < num_groups; i++) {
 314                         if (!strcmp(group, groups[i])) {
 315                                 found = true;
 316                                 break;
 317                         }
 318                 }
 319                 if (!found)
 320                         return -EINVAL;
 321         } else {
 322                 group = groups[0];
 323         }
 324
 325         setting->data.mux.group = pinctrl_get_group_selector(pctldev, group);
 326         if (setting->data.mux.group < 0)
 327                 return setting->data.mux.group;
 328
 329         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 330                                       &num_pins);
 331         if (ret) {
 332                 dev_err(pctldev->dev,
 333                         "could not get pins for device %s group selector %d\n",
 334                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 335                         return -ENODEV;
 336         }
 337
 338         /* Try to allocate all pins in this group, one by one */
 339         for (i = 0; i < num_pins; i++) {
 340                 ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
 341                 if (ret) {
 342                         dev_err(pctldev->dev,
 343                                 "could not get request pin %d on device %s\n",
 344                                 pins[i], pinctrl_dev_get_name(pctldev));
 345                         /* On error release all taken pins */
 346                         i--; /* this pin just failed */
 347                         for (; i >= 0; i--)
 348                                 pin_free(pctldev, pins[i], NULL);
 349                         return -ENODEV;
 350                 }
 351         }
 352
 353         return 0;
 354 }
 355
 356 void pinmux_free_setting(struct pinctrl_setting const *setting)
 357 {
 358         struct pinctrl_dev *pctldev = setting->pctldev;
 359         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 360         const unsigned *pins;
 361         unsigned num_pins;
 362         int ret;
 363         int i;
 364
 365         ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
 366                                       &pins, &num_pins);
 367         if (ret) {
 368                 dev_err(pctldev->dev,
 369                         "could not get pins for device %s group selector %d\n",
 370                         pinctrl_dev_get_name(pctldev), setting->data.mux.group);
 371                 return;
 372         }
 373
 374         for (i = 0; i < num_pins; i++)
 375                 pin_free(pctldev, pins[i], NULL);
 376 }
 377
 378 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 379 {
 380         struct pinctrl_dev *pctldev = setting->pctldev;
 381         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 382
 383         return ops->enable(pctldev, setting->data.mux.func,
 384                            setting->data.mux.group);
 385 }
 386
 387 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 388 {
 389         struct pinctrl_dev *pctldev = setting->pctldev;
 390         const struct pinmux_ops *ops = pctldev->desc->pmxops;
 391
 392         ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 393 }
 394
 395 #ifdef CONFIG_DEBUG_FS
 396
 397 /* Called from pincontrol core */
 398 static int pinmux_functions_show(struct seq_file *s, void *what)
 399 {
 400         struct pinctrl_dev *pctldev = s->private;
 401         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 402         unsigned func_selector = 0;
 403
 404         mutex_lock(&pinctrl_mutex);
 405
 406         while (pmxops->list_functions(pctldev, func_selector) >= 0) {
 407                 const char *func = pmxops->get_function_name(pctldev,
 408                                                           func_selector);
 409                 const char * const *groups;
 410                 unsigned num_groups;
 411                 int ret;
 412                 int i;
 413
 414                 ret = pmxops->get_function_groups(pctldev, func_selector,
 415                                                   &groups, &num_groups);
 416                 if (ret)
 417                         seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 418                                    func);
 419
 420                 seq_printf(s, "function: %s, groups = [ ", func);
 421                 for (i = 0; i < num_groups; i++)
 422                         seq_printf(s, "%s ", groups[i]);
 423                 seq_puts(s, "]\n");
 424
 425                 func_selector++;
 426         }
 427
 428         mutex_unlock(&pinctrl_mutex);
 429
 430         return 0;
 431 }
 432
 433 static int pinmux_pins_show(struct seq_file *s, void *what)
 434 {
 435         struct pinctrl_dev *pctldev = s->private;
 436         unsigned i, pin;
 437
 438         seq_puts(s, "Pinmux settings per pin\n");
 439         seq_puts(s, "Format: pin (name): owner\n");
 440
 441         mutex_lock(&pinctrl_mutex);
 442
 443         /* The pin number can be retrived from the pin controller descriptor */
 444         for (i = 0; i < pctldev->desc->npins; i++) {
 445                 struct pin_desc *desc;
 446                 bool is_hog = false;
 447
 448                 pin = pctldev->desc->pins[i].number;
 449                 desc = pin_desc_get(pctldev, pin);
 450                 /* Skip if we cannot search the pin */
 451                 if (desc == NULL)
 452                         continue;
 453
 454                 if (desc->owner &&
 455                     !strcmp(desc->owner, pinctrl_dev_get_name(pctldev)))
 456                         is_hog = true;
 457
 458                 seq_printf(s, "pin %d (%s): %s%s\n", pin,
 459                            desc->name ? desc->name : "unnamed",
 460                            desc->owner ? desc->owner : "UNCLAIMED",
 461                            is_hog ? " (HOG)" : "");
 462         }
 463
 464         mutex_unlock(&pinctrl_mutex);
 465
 466         return 0;
 467 }
 468
 469 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 470 {
 471         seq_printf(s, "group %s\nfunction %s\n",
 472                 map->data.mux.group ? map->data.mux.group : "(default)",
 473                 map->data.mux.function);
 474 }
 475
 476 void pinmux_show_setting(struct seq_file *s,
 477                          struct pinctrl_setting const *setting)
 478 {
 479         struct pinctrl_dev *pctldev = setting->pctldev;
 480         const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 481         const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 482
 483         seq_printf(s, "group: %s (%u) function: %s (%u)\n",
 484                    pctlops->get_group_name(pctldev, setting->data.mux.group),
 485                    setting->data.mux.group,
 486                    pmxops->get_function_name(pctldev, setting->data.mux.func),
 487                    setting->data.mux.func);
 488 }
 489
 490 static int pinmux_functions_open(struct inode *inode, struct file *file)
 491 {
 492         return single_open(file, pinmux_functions_show, inode->i_private);
 493 }
 494
 495 static int pinmux_pins_open(struct inode *inode, struct file *file)
 496 {
 497         return single_open(file, pinmux_pins_show, inode->i_private);
 498 }
 499
 500 static const struct file_operations pinmux_functions_ops = {
 501         .open           = pinmux_functions_open,
 502         .read           = seq_read,
 503         .llseek         = seq_lseek,
 504         .release        = single_release,
 505 };
 506
 507 static const struct file_operations pinmux_pins_ops = {
 508         .open           = pinmux_pins_open,
 509         .read           = seq_read,
 510         .llseek         = seq_lseek,
 511         .release        = single_release,
 512 };
 513
 514 void pinmux_init_device_debugfs(struct dentry *devroot,
 515                          struct pinctrl_dev *pctldev)
 516 {
 517         debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
 518                             devroot, pctldev, &pinmux_functions_ops);
 519         debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
 520                             devroot, pctldev, &pinmux_pins_ops);
 521 }
 522
 523 #endif /* CONFIG_DEBUG_FS */