/*
   * Driver core interface to the pinctrl subsystem.
   *
   * Copyright (C) 2012 ST-Ericsson SA
   * Written on behalf of Linaro for ST-Ericsson
   * Based on bits of regulator core, gpio core and clk core
   *
   * Author: Linus Walleij <linus.walleij@linaro.org>
   *
   * License terms: GNU General Public License (GPL) version 2
   */
  
  #include <linux/device.h>
  #include <linux/pinctrl/devinfo.h>
  #include <linux/pinctrl/consumer.h>
  #include <linux/slab.h>
  
  /**
   * pinctrl_bind_pins() - called by the device core before probe
   * @dev: the device that is just about to probe
   */
  int pinctrl_bind_pins(struct device *dev)
  {
  	int ret;

  	if (dev->of_node_reused)
  		return 0;

  	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
  	if (!dev->pins)
  		return -ENOMEM;
  
  	dev->pins->p = devm_pinctrl_get(dev);
  	if (IS_ERR(dev->pins->p)) {
  		dev_dbg(dev, "no pinctrl handle
  ");
  		ret = PTR_ERR(dev->pins->p);
  		goto cleanup_alloc;
  	}
  
  	dev->pins->default_state = pinctrl_lookup_state(dev->pins->p,
  					PINCTRL_STATE_DEFAULT);
  	if (IS_ERR(dev->pins->default_state)) {
  		dev_dbg(dev, "no default pinctrl state
  ");
  		ret = 0;
  		goto cleanup_get;
  	}

  	dev->pins->init_state = pinctrl_lookup_state(dev->pins->p,
  					PINCTRL_STATE_INIT);
  	if (IS_ERR(dev->pins->init_state)) {
  		/* Not supplying this state is perfectly legal */
  		dev_dbg(dev, "no init pinctrl state
  ");
  
  		ret = pinctrl_select_state(dev->pins->p,
  					   dev->pins->default_state);
  	} else {
  		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
  	}

  	if (ret) {

  		dev_dbg(dev, "failed to activate initial pinctrl state
  ");

  		goto cleanup_get;
  	}

  #ifdef CONFIG_PM
  	/*
  	 * If power management is enabled, we also look for the optional
  	 * sleep and idle pin states, with semantics as defined in
  	 * <linux/pinctrl/pinctrl-state.h>
  	 */
  	dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
  					PINCTRL_STATE_SLEEP);
  	if (IS_ERR(dev->pins->sleep_state))
  		/* Not supplying this state is perfectly legal */
  		dev_dbg(dev, "no sleep pinctrl state
  ");
  
  	dev->pins->idle_state = pinctrl_lookup_state(dev->pins->p,
  					PINCTRL_STATE_IDLE);
  	if (IS_ERR(dev->pins->idle_state))
  		/* Not supplying this state is perfectly legal */
  		dev_dbg(dev, "no idle pinctrl state
  ");
  #endif

  	return 0;
  
  	/*
  	 * If no pinctrl handle or default state was found for this device,
  	 * let's explicitly free the pin container in the device, there is
  	 * no point in keeping it around.
  	 */
  cleanup_get:
  	devm_pinctrl_put(dev->pins->p);
  cleanup_alloc:
  	devm_kfree(dev, dev->pins);
  	dev->pins = NULL;

  	/* Return deferrals */
  	if (ret == -EPROBE_DEFER)
  		return ret;
  	/* Return serious errors */
  	if (ret == -EINVAL)
  		return ret;
  	/* We ignore errors like -ENOENT meaning no pinctrl state */

  	return 0;

  }