/*
   * Copyright (c) 2015 Google, Inc
   * Written by Simon Glass <sjg@chromium.org>

   * Copyright (c) 2016, NVIDIA CORPORATION.

   *
   * SPDX-License-Identifier:	GPL-2.0+
   */

  #ifndef _CLK_H_
  #define _CLK_H_

  #include <linux/errno.h>

  #include <linux/types.h>

  /**
   * A clock is a hardware signal that oscillates autonomously at a specific
   * frequency and duty cycle. Most hardware modules require one or more clock
   * signal to drive their operation. Clock signals are typically generated
   * externally to the HW module consuming them, by an entity this API calls a
   * clock provider. This API provides a standard means for drivers to enable and
   * disable clocks, and to set the rate at which they oscillate.
   *
   * A driver that implements UCLASS_CLOCK is a clock provider. A provider will
   * often implement multiple separate clocks, since the hardware it manages
   * often has this capability. clock_uclass.h describes the interface which
   * clock providers must implement.
   *
   * Clock consumers/clients are the HW modules driven by the clock signals. This
   * header file describes the API used by drivers for those HW modules.
   */

  struct udevice;

  /**
   * struct clk - A handle to (allowing control of) a single clock.
   *
   * Clients provide storage for clock handles. The content of the structure is
   * managed solely by the clock API and clock drivers. A clock struct is
   * initialized by "get"ing the clock struct. The clock struct is passed to all
   * other clock APIs to identify which clock signal to operate upon.
   *
   * @dev: The device which implements the clock signal.
   * @id: The clock signal ID within the provider.
   *
   * Currently, the clock API assumes that a single integer ID is enough to
   * identify and configure any clock signal for any clock provider. If this
   * assumption becomes invalid in the future, the struct could be expanded to
   * either (a) add more fields to allow clock providers to store additional
   * information, or (b) replace the id field with an opaque pointer, which the
   * provider would dynamically allocated during its .of_xlate op, and process
   * during is .request op. This may require the addition of an extra op to clean
   * up the allocation.
   */
  struct clk {
  	struct udevice *dev;
  	/*
  	 * Written by of_xlate. We assume a single id is enough for now. In the
  	 * future, we might add more fields here.

  	 */

  	unsigned long id;

  };

  #if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK)

  struct phandle_1_arg;

  int clk_get_by_index_platdata(struct udevice *dev, int index,

  			      struct phandle_1_arg *cells, struct clk *clk);

  /**
   * clock_get_by_index - Get/request a clock by integer index.
   *
   * This looks up and requests a clock. The index is relative to the client
   * device; each device is assumed to have n clocks associated with it somehow,
   * and this function finds and requests one of them. The mapping of client
   * device clock indices to provider clocks may be via device-tree properties,
   * board-provided mapping tables, or some other mechanism.
   *
   * @dev:	The client device.
   * @index:	The index of the clock to request, within the client's list of
   *		clocks.
   * @clock	A pointer to a clock struct to initialize.
   * @return 0 if OK, or a negative error code.
   */
  int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);

  
  /**

   * clock_get_by_name - Get/request a clock by name.

   *

   * This looks up and requests a clock. The name is relative to the client
   * device; each device is assumed to have n clocks associated with it somehow,
   * and this function finds and requests one of them. The mapping of client
   * device clock names to provider clocks may be via device-tree properties,
   * board-provided mapping tables, or some other mechanism.
   *
   * @dev:	The client device.
   * @name:	The name of the clock to request, within the client's list of
   *		clocks.
   * @clock:	A pointer to a clock struct to initialize.
   * @return 0 if OK, or a negative error code.

   */

  int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);

  
  /**
   * clk_release_all() - Disable (turn off)/Free an array of previously
   * requested clocks.
   *
   * For each clock contained in the clock array, this function will check if
   * clock has been previously requested and then will disable and free it.
   *
   * @clk:	A clock struct array that was previously successfully
   *		requested by clk_request/get_by_*().
   * @count	Number of clock contained in the array
   * @return zero on success, or -ve error code.
   */
  int clk_release_all(struct clk *clk, int count);

  #else
  static inline int clk_get_by_index(struct udevice *dev, int index,
  				   struct clk *clk)
  {
  	return -ENOSYS;
  }
  
  static inline int clk_get_by_name(struct udevice *dev, const char *name,
  			   struct clk *clk)
  {
  	return -ENOSYS;
  }

  
  static inline int clk_release_all(struct clk *clk, int count)
  {
  	return -ENOSYS;
  }

  #endif

  #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
  	CONFIG_IS_ENABLED(CLK)
  /**
   * clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
   *                    properties to configure clocks
   *
   * @dev:        A device to process (the ofnode associated with this device
   *              will be processed).
   */
  int clk_set_defaults(struct udevice *dev);
  #else
  static inline int clk_set_defaults(struct udevice *dev)
  {
  	return 0;
  }
  #endif

  /**

   * clk_request - Request a clock by provider-specific ID.

   *

   * This requests a clock using a provider-specific ID. Generally, this function
   * should not be used, since clk_get_by_index/name() provide an interface that
   * better separates clients from intimate knowledge of clock providers.
   * However, this function may be useful in core SoC-specific code.
   *
   * @dev:	The clock provider device.
   * @clock:	A pointer to a clock struct to initialize. The caller must
   *		have already initialized any field in this struct which the
   *		clock provider uses to identify the clock.
   * @return 0 if OK, or a negative error code.

   */

  int clk_request(struct udevice *dev, struct clk *clk);

  
  /**

   * clock_free - Free a previously requested clock.

   *

   * @clock:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @return 0 if OK, or a negative error code.

   */

  int clk_free(struct clk *clk);

  
  /**

   * clk_get_rate() - Get current clock rate.

   *

   * @clk:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @return clock rate in Hz, or -ve error code.

   */

  ulong clk_get_rate(struct clk *clk);

  
  /**

   * clk_set_rate() - Set current clock rate.

   *

   * @clk:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @rate:	New clock rate in Hz.
   * @return new rate, or -ve error code.

   */

  ulong clk_set_rate(struct clk *clk, ulong rate);

  /**

   * clk_set_parent() - Set current clock parent.
   *
   * @clk:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @parent:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @return new rate, or -ve error code.
   */
  int clk_set_parent(struct clk *clk, struct clk *parent);
  
  /**

   * clk_enable() - Enable (turn on) a clock.

   *

   * @clk:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @return zero on success, or -ve error code.
   */
  int clk_enable(struct clk *clk);
  
  /**
   * clk_disable() - Disable (turn off) a clock.

   *

   * @clk:	A clock struct that was previously successfully requested by
   *		clk_request/get_by_*().
   * @return zero on success, or -ve error code.

   */

  int clk_disable(struct clk *clk);

  int soc_clk_dump(void);
  
  #endif