linux/drivers/clk/zynqmp/clk-mux-zynqmp.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Zynq UltraScale+ MPSoC mux
 *
 *  Copyright (C) 2016-2018 Xilinx
 */

#include <linux/clk-provider.h>
#include <linux/slab.h>
#include "clk-zynqmp.h"

/*
 * DOC: basic adjustable multiplexer clock that cannot gate
 *
 * Traits of this clock:
 * prepare - clk_prepare only ensures that parents are prepared
 * enable - clk_enable only ensures that parents are enabled
 * rate - rate is only affected by parent switching.  No clk_set_rate support
 * parent - parent is adjustable through clk_set_parent
 */

/**
 * struct zynqmp_clk_mux - multiplexer clock
 *
 * @hw:		handle between common and hardware-specific interfaces
 * @flags:	hardware-specific flags
 * @clk_id:	Id of clock
 */
struct zynqmp_clk_mux {
	struct clk_hw hw;
	u8 flags;
	u32 clk_id;
};

#define to_zynqmp_clk_mux(_hw) container_of(_hw, struct zynqmp_clk_mux, hw)

/**
 * zynqmp_clk_mux_get_parent() - Get parent of clock
 * @hw:		handle between common and hardware-specific interfaces
 *
 * Return: Parent index on success or number of parents in case of error
 */
static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
{
	struct zynqmp_clk_mux *mux = to_zynqmp_clk_mux(hw);
	const char *clk_name = clk_hw_get_name(hw);
	u32 clk_id = mux->clk_id;
	u32 val;
	int ret;

	ret = zynqmp_pm_clock_getparent(clk_id, &val);

	if (ret) {
		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
			     __func__, clk_name, ret);
		/*
		 * clk_core_get_parent_by_index() takes num_parents as incorrect
		 * index which is exactly what I want to return here
		 */
		return clk_hw_get_num_parents(hw);
	}

	return val;
}

/**
 * zynqmp_clk_mux_set_parent() - Set parent of clock
 * @hw:		handle between common and hardware-specific interfaces
 * @index:	Parent index
 *
 * Return: 0 on success else error+reason
 */
static int zynqmp_clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
	struct zynqmp_clk_mux *mux = to_zynqmp_clk_mux(hw);
	const char *clk_name = clk_hw_get_name(hw);
	u32 clk_id = mux->clk_id;
	int ret;

	ret = zynqmp_pm_clock_setparent(clk_id, index);

	if (ret)
		pr_warn_once("%s() set parent failed for clock: %s, ret = %d\n",
			     __func__, clk_name, ret);

	return ret;
}

static const struct clk_ops zynqmp_clk_mux_ops = {
	.get_parent = zynqmp_clk_mux_get_parent,
	.set_parent = zynqmp_clk_mux_set_parent,
	.determine_rate = __clk_mux_determine_rate,
};

static const struct clk_ops zynqmp_clk_mux_ro_ops = {
	.get_parent = zynqmp_clk_mux_get_parent,
};

/**
 * zynqmp_clk_register_mux() - Register a mux table with the clock
 *			       framework
 * @name:		Name of this clock
 * @clk_id:		Id of this clock
 * @parents:		Name of this clock's parents
 * @num_parents:	Number of parents
 * @nodes:		Clock topology node
 *
 * Return: clock hardware of the registered clock mux
 */
struct clk_hw *zynqmp_clk_register_mux(const char *name, u32 clk_id,
				       const char * const *parents,
				       u8 num_parents,
				       const struct clock_topology *nodes)
{
	struct zynqmp_clk_mux *mux;
	struct clk_hw *hw;
	struct clk_init_data init;
	int ret;

	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
	if (!mux)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	if (nodes->type_flag & CLK_MUX_READ_ONLY)
		init.ops = &zynqmp_clk_mux_ro_ops;
	else
		init.ops = &zynqmp_clk_mux_ops;
	init.flags = nodes->flag;
	init.parent_names = parents;
	init.num_parents = num_parents;
	mux->flags = nodes->type_flag;
	mux->hw.init = &init;
	mux->clk_id = clk_id;

	hw = &mux->hw;
	ret = clk_hw_register(NULL, hw);
	if (ret) {
		kfree(hw);
		hw = ERR_PTR(ret);
	}

	return hw;
}