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 <[email protected]>
   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         if (dev->of_node_reused)
  27                 return 0;
  28
  29         dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
  30         if (!dev->pins)
  31                 return -ENOMEM;
  32
  33         dev->pins->p = devm_pinctrl_get(dev);
  34         if (IS_ERR(dev->pins->p)) {
  35                 dev_dbg(dev, "no pinctrl handle\n");
  36                 ret = PTR_ERR(dev->pins->p);
  37                 goto cleanup_alloc;
  38         }
  39
  40         dev->pins->default_state = pinctrl_lookup_state(dev->pins->p,
  41                                         PINCTRL_STATE_DEFAULT);
  42         if (IS_ERR(dev->pins->default_state)) {
  43                 dev_dbg(dev, "no default pinctrl state\n");
  44                 ret = 0;
  45                 goto cleanup_get;
  46         }
  47
  48         dev->pins->init_state = pinctrl_lookup_state(dev->pins->p,
  49                                         PINCTRL_STATE_INIT);
  50         if (IS_ERR(dev->pins->init_state)) {
  51                 /* Not supplying this state is perfectly legal */
  52                 dev_dbg(dev, "no init pinctrl state\n");
  53
  54                 ret = pinctrl_select_state(dev->pins->p,
  55                                            dev->pins->default_state);
  56         } else {
  57                 ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
  58         }
  59
  60         if (ret) {
  61                 dev_dbg(dev, "failed to activate initial pinctrl state\n");
  62                 goto cleanup_get;
  63         }
  64
  65 #ifdef CONFIG_PM
  66         /*
  67          * If power management is enabled, we also look for the optional
  68          * sleep and idle pin states, with semantics as defined in
  69          * <linux/pinctrl/pinctrl-state.h>
  70          */
  71         dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
  72                                         PINCTRL_STATE_SLEEP);
  73         if (IS_ERR(dev->pins->sleep_state))
  74                 /* Not supplying this state is perfectly legal */
  75                 dev_dbg(dev, "no sleep pinctrl state\n");
  76
  77         dev->pins->idle_state = pinctrl_lookup_state(dev->pins->p,
  78                                         PINCTRL_STATE_IDLE);
  79         if (IS_ERR(dev->pins->idle_state))
  80                 /* Not supplying this state is perfectly legal */
  81                 dev_dbg(dev, "no idle pinctrl state\n");
  82 #endif
  83
  84         return 0;
  85
  86         /*
  87          * If no pinctrl handle or default state was found for this device,
  88          * let's explicitly free the pin container in the device, there is
  89          * no point in keeping it around.
  90          */
  91 cleanup_get:
  92         devm_pinctrl_put(dev->pins->p);
  93 cleanup_alloc:
  94         devm_kfree(dev, dev->pins);
  95         dev->pins = NULL;
  96
  97         /* Return deferrals */
  98         if (ret == -EPROBE_DEFER)
  99                 return ret;
 100         /* Return serious errors */
 101         if (ret == -EINVAL)
 102                 return ret;
 103         /* We ignore errors like -ENOENT meaning no pinctrl state */
 104
 105         return 0;
 106 }