clk: Versatile Express clock generators ("osc") driver

obj-$(CONFIG_ICST)		+= clk-icst.o

obj-$(CONFIG_ARCH_INTEGRATOR)	+= clk-integrator.o

obj-$(CONFIG_ARCH_REALVIEW)	+= clk-realview.o

obj-$(CONFIG_VEXPRESS_CONFIG)	+= clk-vexpress-osc.o

/*

 * 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);

}