drivers/base/pinctrl.c

   1 /*
   2  * Driver core interface to the pinctrl subsystem.
   3  *
   4  * Copyright (C) 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  * License terms: GNU General Public License (GPL) version 2
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/pinctrl/devinfo.h>
  15 #include <linux/pinctrl/consumer.h>
  16 #include <linux/slab.h>
  17
  18 /**
  19  * pinctrl_bind_pins() - called by the device core before probe
  20  * @dev: the device that is just about to probe
  21  */
  22 int pinctrl_bind_pins(struct device *dev)
  23 {
  24         int ret;
  25
  26         dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
  27         if (!dev->pins)
  28                 return -ENOMEM;
  29
  30         dev->pins->p = devm_pinctrl_get(dev);
  31         if (IS_ERR(dev->pins->p)) {
  32                 dev_dbg(dev, "no pinctrl handle\n");
  33                 ret = PTR_ERR(dev->pins->p);
  34                 goto cleanup_alloc;
  35         }
  36
  37         dev->pins->default_state = pinctrl_lookup_state(dev->pins->p,
  38                                         PINCTRL_STATE_DEFAULT);
  39         if (IS_ERR(dev->pins->default_state)) {
  40                 dev_dbg(dev, "no default pinctrl state\n");
  41                 ret = 0;
  42                 goto cleanup_get;
  43         }
  44
  45         ret = pinctrl_select_state(dev->pins->p, dev->pins->default_state);
  46         if (ret) {
  47                 dev_dbg(dev, "failed to activate default pinctrl state\n");
  48                 goto cleanup_get;
  49         }
  50
  51 #ifdef CONFIG_PM
  52         /*
  53          * If power management is enabled, we also look for the optional
  54          * sleep and idle pin states, with semantics as defined in
  55          * <linux/pinctrl/pinctrl-state.h>
  56          */
  57         dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
  58                                         PINCTRL_STATE_SLEEP);
  59         if (IS_ERR(dev->pins->sleep_state))
  60                 /* Not supplying this state is perfectly legal */
  61                 dev_dbg(dev, "no sleep pinctrl state\n");
  62
  63         dev->pins->idle_state = pinctrl_lookup_state(dev->pins->p,
  64                                         PINCTRL_STATE_IDLE);
  65         if (IS_ERR(dev->pins->idle_state))
  66                 /* Not supplying this state is perfectly legal */
  67                 dev_dbg(dev, "no idle pinctrl state\n");
  68 #endif
  69
  70         return 0;
  71
  72         /*
  73          * If no pinctrl handle or default state was found for this device,
  74          * let's explicitly free the pin container in the device, there is
  75          * no point in keeping it around.
  76          */
  77 cleanup_get:
  78         devm_pinctrl_put(dev->pins->p);
  79 cleanup_alloc:
  80         devm_kfree(dev, dev->pins);
  81         dev->pins = NULL;
  82
  83         /* Only return deferrals */
  84         if (ret != -EPROBE_DEFER)
  85                 ret = 0;
  86
  87         return ret;
  88 }