1/*
2 * TI clock autoidle support
3 *
4 * Copyright (C) 2013 Texas Instruments, Inc.
5 *
6 * Tero Kristo <t-kristo@ti.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
13 * kind, whether express or implied; without even the implied warranty
14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 */
17
18#include <linux/clk-provider.h>
19#include <linux/slab.h>
20#include <linux/io.h>
21#include <linux/of.h>
22#include <linux/of_address.h>
23#include <linux/clk/ti.h>
24
25struct clk_ti_autoidle {
26	void __iomem		*reg;
27	u8			shift;
28	u8			flags;
29	const char		*name;
30	struct list_head	node;
31};
32
33#define AUTOIDLE_LOW		0x1
34
35static LIST_HEAD(autoidle_clks);
36
37static void ti_allow_autoidle(struct clk_ti_autoidle *clk)
38{
39	u32 val;
40
41	val = ti_clk_ll_ops->clk_readl(clk->reg);
42
43	if (clk->flags & AUTOIDLE_LOW)
44		val &= ~(1 << clk->shift);
45	else
46		val |= (1 << clk->shift);
47
48	ti_clk_ll_ops->clk_writel(val, clk->reg);
49}
50
51static void ti_deny_autoidle(struct clk_ti_autoidle *clk)
52{
53	u32 val;
54
55	val = ti_clk_ll_ops->clk_readl(clk->reg);
56
57	if (clk->flags & AUTOIDLE_LOW)
58		val |= (1 << clk->shift);
59	else
60		val &= ~(1 << clk->shift);
61
62	ti_clk_ll_ops->clk_writel(val, clk->reg);
63}
64
65/**
66 * of_ti_clk_allow_autoidle_all - enable autoidle for all clocks
67 *
68 * Enables hardware autoidle for all registered DT clocks, which have
69 * the feature.
70 */
71void of_ti_clk_allow_autoidle_all(void)
72{
73	struct clk_ti_autoidle *c;
74
75	list_for_each_entry(c, &autoidle_clks, node)
76		ti_allow_autoidle(c);
77}
78
79/**
80 * of_ti_clk_deny_autoidle_all - disable autoidle for all clocks
81 *
82 * Disables hardware autoidle for all registered DT clocks, which have
83 * the feature.
84 */
85void of_ti_clk_deny_autoidle_all(void)
86{
87	struct clk_ti_autoidle *c;
88
89	list_for_each_entry(c, &autoidle_clks, node)
90		ti_deny_autoidle(c);
91}
92
93/**
94 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
95 * @node: pointer to the clock device node
96 *
97 * Checks if a clock has hardware autoidle support or not (check
98 * for presence of 'ti,autoidle-shift' property in the device tree
99 * node) and sets up the hardware autoidle feature for the clock
100 * if available. If autoidle is available, the clock is also added
101 * to the autoidle list for later processing. Returns 0 on success,
102 * negative error value on failure.
103 */
104int __init of_ti_clk_autoidle_setup(struct device_node *node)
105{
106	u32 shift;
107	struct clk_ti_autoidle *clk;
108
109	/* Check if this clock has autoidle support or not */
110	if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
111		return 0;
112
113	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
114
115	if (!clk)
116		return -ENOMEM;
117
118	clk->shift = shift;
119	clk->name = node->name;
120	clk->reg = ti_clk_get_reg_addr(node, 0);
121
122	if (IS_ERR(clk->reg)) {
123		kfree(clk);
124		return -EINVAL;
125	}
126
127	if (of_property_read_bool(node, "ti,invert-autoidle-bit"))
128		clk->flags |= AUTOIDLE_LOW;
129
130	list_add(&clk->node, &autoidle_clks);
131
132	return 0;
133}
134