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) 2013 ARM Limited
 12 */
 13
 14#include <linux/amba/sp810.h>
 15#include <linux/slab.h>
 16#include <linux/clk.h>
 17#include <linux/clk-provider.h>
 18#include <linux/err.h>
 19#include <linux/of.h>
 20#include <linux/of_address.h>
 21
 22#define to_clk_sp810_timerclken(_hw) \
 23		container_of(_hw, struct clk_sp810_timerclken, hw)
 24
 25struct clk_sp810;
 26
 27struct clk_sp810_timerclken {
 28	struct clk_hw hw;
 29	struct clk *clk;
 30	struct clk_sp810 *sp810;
 31	int channel;
 32};
 33
 34struct clk_sp810 {
 35	struct device_node *node;
 36	void __iomem *base;
 37	spinlock_t lock;
 38	struct clk_sp810_timerclken timerclken[4];
 39};
 40
 41static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
 42{
 43	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
 44	u32 val = readl(timerclken->sp810->base + SCCTRL);
 45
 46	return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
 47}
 48
 49static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
 50{
 51	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
 52	struct clk_sp810 *sp810 = timerclken->sp810;
 53	u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
 54	unsigned long flags = 0;
 55
 56	if (WARN_ON(index > 1))
 57		return -EINVAL;
 58
 59	spin_lock_irqsave(&sp810->lock, flags);
 60
 61	val = readl(sp810->base + SCCTRL);
 62	val &= ~(1 << shift);
 63	val |= index << shift;
 64	writel(val, sp810->base + SCCTRL);
 65
 66	spin_unlock_irqrestore(&sp810->lock, flags);
 67
 68	return 0;
 69}
 70
 71static const struct clk_ops clk_sp810_timerclken_ops = {
 72	.get_parent = clk_sp810_timerclken_get_parent,
 73	.set_parent = clk_sp810_timerclken_set_parent,
 74};
 75
 76static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
 77		void *data)
 78{
 79	struct clk_sp810 *sp810 = data;
 80
 81	if (WARN_ON(clkspec->args_count != 1 ||
 82		    clkspec->args[0] >=	ARRAY_SIZE(sp810->timerclken)))
 83		return NULL;
 84
 85	return sp810->timerclken[clkspec->args[0]].clk;
 86}
 87
 88static void __init clk_sp810_of_setup(struct device_node *node)
 89{
 90	struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
 91	const char *parent_names[2];
 92	int num = ARRAY_SIZE(parent_names);
 93	char name[12];
 94	struct clk_init_data init;
 95	static int instance;
 96	int i;
 97	bool deprecated;
 98
 99	if (!sp810)
100		return;
101
102	if (of_clk_parent_fill(node, parent_names, num) != num) {
103		pr_warn("Failed to obtain parent clocks for SP810!\n");
104		kfree(sp810);
105		return;
106	}
107
108	sp810->node = node;
109	sp810->base = of_iomap(node, 0);
110	spin_lock_init(&sp810->lock);
111
112	init.name = name;
113	init.ops = &clk_sp810_timerclken_ops;
114	init.flags = CLK_IS_BASIC;
115	init.parent_names = parent_names;
116	init.num_parents = num;
117
118	deprecated = !of_find_property(node, "assigned-clock-parents", NULL);
119
120	for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
121		snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);
122
123		sp810->timerclken[i].sp810 = sp810;
124		sp810->timerclken[i].channel = i;
125		sp810->timerclken[i].hw.init = &init;
126
127		/*
128		 * If DT isn't setting the parent, force it to be
129		 * the 1 MHz clock without going through the framework.
130		 * We do this before clk_register() so that it can determine
131		 * the parent and setup the tree properly.
132		 */
133		if (deprecated)
134			init.ops->set_parent(&sp810->timerclken[i].hw, 1);
135
136		sp810->timerclken[i].clk = clk_register(NULL,
137				&sp810->timerclken[i].hw);
138		WARN_ON(IS_ERR(sp810->timerclken[i].clk));
139	}
140
141	of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
142	instance++;
143}
144CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);