1. 根目录:
2. drivers
3. clk
4. versatile
5. clk-vexpress-osc.c

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Copyright (C) 2012 ARM Limited
 */

#define pr_fmt(fmt) "vexpress-osc: " fmt

#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/vexpress.h>

struct vexpress_osc {
	struct vexpress_config_func *func;
	struct clk_hw hw;
	unsigned long rate_min;
	unsigned long rate_max;
};

#define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)

static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
		unsigned long parent_rate)
{
	struct vexpress_osc *osc = to_vexpress_osc(hw);
	u32 rate;

	vexpress_config_read(osc->func, 0, &rate);

	return rate;
}

static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
		unsigned long *parent_rate)
{
	struct vexpress_osc *osc = to_vexpress_osc(hw);

	if (WARN_ON(osc->rate_min && rate < osc->rate_min))
		rate = osc->rate_min;

	if (WARN_ON(osc->rate_max && rate > osc->rate_max))
		rate = osc->rate_max;

	return rate;
}

static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
		unsigned long parent_rate)
{
	struct vexpress_osc *osc = to_vexpress_osc(hw);

	return vexpress_config_write(osc->func, 0, rate);
}

static struct clk_ops vexpress_osc_ops = {
	.recalc_rate = vexpress_osc_recalc_rate,
	.round_rate = vexpress_osc_round_rate,
	.set_rate = vexpress_osc_set_rate,
};


struct clk * __init vexpress_osc_setup(struct device *dev)
{
	struct clk_init_data init;
	struct vexpress_osc *osc = kzalloc(sizeof(*osc), GFP_KERNEL);

	if (!osc)
		return NULL;

	osc->func = vexpress_config_func_get_by_dev(dev);
	if (!osc->func) {
		kfree(osc);
		return NULL;
	}

	init.name = dev_name(dev);
	init.ops = &vexpress_osc_ops;
	init.flags = CLK_IS_ROOT;
	init.num_parents = 0;
	osc->hw.init = &init;

	return clk_register(NULL, &osc->hw);
}

void __init vexpress_osc_of_setup(struct device_node *node)
{
	struct clk_init_data init;
	struct vexpress_osc *osc;
	struct clk *clk;
	u32 range[2];

	osc = kzalloc(sizeof(*osc), GFP_KERNEL);
	if (!osc)
		goto error;

	osc->func = vexpress_config_func_get_by_node(node);
	if (!osc->func) {
		pr_err("Failed to obtain config func for node '%s'!\n",
				node->name);
		goto error;
	}

	if (of_property_read_u32_array(node, "freq-range", range,
			ARRAY_SIZE(range)) == 0) {
		osc->rate_min = range[0];
		osc->rate_max = range[1];
	}

	of_property_read_string(node, "clock-output-names", &init.name);
	if (!init.name)
		init.name = node->name;

	init.ops = &vexpress_osc_ops;
	init.flags = CLK_IS_ROOT;
	init.num_parents = 0;

	osc->hw.init = &init;

	clk = clk_register(NULL, &osc->hw);
	if (IS_ERR(clk)) {
		pr_err("Failed to register clock '%s'!\n", init.name);
		goto error;
	}

	of_clk_add_provider(node, of_clk_src_simple_get, clk);

	pr_debug("Registered clock '%s'\n", init.name);

	return;

error:
	if (osc->func)
		vexpress_config_func_put(osc->func);
	kfree(osc);
}
CLK_OF_DECLARE(vexpress_soc, "arm,vexpress-osc", vexpress_osc_of_setup);