1/*
  2 * This program is free software; you can redistribute it and/or modify
  3 * it under the terms of the GNU General Public License version 2 as
  4 * published by the Free Software Foundation.
  5 *
  6 * This program is distributed in the hope that it will be useful,
  7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  9 * GNU General Public License for more details.
 10 *
 11 * Copyright (C) 2012 ARM Limited
 12 */
 13
 14#include <linux/clkdev.h>
 15#include <linux/clk-provider.h>
 16#include <linux/err.h>
 17#include <linux/of.h>
 18#include <linux/platform_device.h>
 19#include <linux/slab.h>
 20#include <linux/vexpress.h>
 21
 22struct vexpress_osc {
 23	struct regmap *reg;
 24	struct clk_hw hw;
 25	unsigned long rate_min;
 26	unsigned long rate_max;
 27};
 28
 29#define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
 30
 31static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
 32		unsigned long parent_rate)
 33{
 34	struct vexpress_osc *osc = to_vexpress_osc(hw);
 35	u32 rate;
 36
 37	regmap_read(osc->reg, 0, &rate);
 38
 39	return rate;
 40}
 41
 42static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
 43		unsigned long *parent_rate)
 44{
 45	struct vexpress_osc *osc = to_vexpress_osc(hw);
 46
 47	if (WARN_ON(osc->rate_min && rate < osc->rate_min))
 48		rate = osc->rate_min;
 49
 50	if (WARN_ON(osc->rate_max && rate > osc->rate_max))
 51		rate = osc->rate_max;
 52
 53	return rate;
 54}
 55
 56static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
 57		unsigned long parent_rate)
 58{
 59	struct vexpress_osc *osc = to_vexpress_osc(hw);
 60
 61	return regmap_write(osc->reg, 0, rate);
 62}
 63
 64static struct clk_ops vexpress_osc_ops = {
 65	.recalc_rate = vexpress_osc_recalc_rate,
 66	.round_rate = vexpress_osc_round_rate,
 67	.set_rate = vexpress_osc_set_rate,
 68};
 69
 70
 71static int vexpress_osc_probe(struct platform_device *pdev)
 72{
 73	struct clk_init_data init;
 74	struct vexpress_osc *osc;
 75	struct clk *clk;
 76	u32 range[2];
 77
 78	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
 79	if (!osc)
 80		return -ENOMEM;
 81
 82	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
 83	if (IS_ERR(osc->reg))
 84		return PTR_ERR(osc->reg);
 85
 86	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
 87			ARRAY_SIZE(range)) == 0) {
 88		osc->rate_min = range[0];
 89		osc->rate_max = range[1];
 90	}
 91
 92	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
 93			&init.name) != 0)
 94		init.name = dev_name(&pdev->dev);
 95
 96	init.ops = &vexpress_osc_ops;
 97	init.flags = 0;
 98	init.num_parents = 0;
 99
100	osc->hw.init = &init;
101
102	clk = clk_register(NULL, &osc->hw);
103	if (IS_ERR(clk))
104		return PTR_ERR(clk);
105
106	of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
107
108	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
109
110	return 0;
111}
112
113static const struct of_device_id vexpress_osc_of_match[] = {
114	{ .compatible = "arm,vexpress-osc", },
115	{}
116};
117
118static struct platform_driver vexpress_osc_driver = {
119	.driver	= {
120		.name = "vexpress-osc",
121		.of_match_table = vexpress_osc_of_match,
122	},
123	.probe = vexpress_osc_probe,
124};
125
126static int __init vexpress_osc_init(void)
127{
128	return platform_driver_register(&vexpress_osc_driver);
129}
130core_initcall(vexpress_osc_init);