1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * TI clock autoidle support
4 *
5 * Copyright (C) 2013 Texas Instruments, Inc.
6 *
7 * Tero Kristo <t-kristo@ti.com>
8 */
9
10#include <linux/clk-provider.h>
11#include <linux/slab.h>
12#include <linux/io.h>
13#include <linux/of.h>
14#include <linux/of_address.h>
15#include <linux/clk/ti.h>
16
17#include "clock.h"
18
19struct clk_ti_autoidle {
20 struct clk_omap_reg reg;
21 u8 shift;
22 u8 flags;
23 const char *name;
24 struct list_head node;
25};
26
27#define AUTOIDLE_LOW 0x1
28
29static LIST_HEAD(autoidle_clks);
30
31/*
32 * we have some non-atomic read/write
33 * operations behind it, so lets
34 * take one lock for handling autoidle
35 * of all clocks
36 */
37static DEFINE_SPINLOCK(autoidle_spinlock);
38
39static int _omap2_clk_deny_idle(struct clk_hw_omap *clk)
40{
41 if (clk->ops && clk->ops->deny_idle) {
42 unsigned long irqflags;
43
44 spin_lock_irqsave(&autoidle_spinlock, irqflags);
45 clk->autoidle_count++;
46 if (clk->autoidle_count == 1)
47 clk->ops->deny_idle(clk);
48
49 spin_unlock_irqrestore(lock: &autoidle_spinlock, flags: irqflags);
50 }
51 return 0;
52}
53
54static int _omap2_clk_allow_idle(struct clk_hw_omap *clk)
55{
56 if (clk->ops && clk->ops->allow_idle) {
57 unsigned long irqflags;
58
59 spin_lock_irqsave(&autoidle_spinlock, irqflags);
60 clk->autoidle_count--;
61 if (clk->autoidle_count == 0)
62 clk->ops->allow_idle(clk);
63
64 spin_unlock_irqrestore(lock: &autoidle_spinlock, flags: irqflags);
65 }
66 return 0;
67}
68
69/**
70 * omap2_clk_deny_idle - disable autoidle on an OMAP clock
71 * @clk: struct clk * to disable autoidle for
72 *
73 * Disable autoidle on an OMAP clock.
74 */
75int omap2_clk_deny_idle(struct clk *clk)
76{
77 struct clk_hw *hw;
78
79 if (!clk)
80 return -EINVAL;
81
82 hw = __clk_get_hw(clk);
83
84 if (omap2_clk_is_hw_omap(hw)) {
85 struct clk_hw_omap *c = to_clk_hw_omap(hw);
86
87 return _omap2_clk_deny_idle(clk: c);
88 }
89
90 return -EINVAL;
91}
92
93/**
94 * omap2_clk_allow_idle - enable autoidle on an OMAP clock
95 * @clk: struct clk * to enable autoidle for
96 *
97 * Enable autoidle on an OMAP clock.
98 */
99int omap2_clk_allow_idle(struct clk *clk)
100{
101 struct clk_hw *hw;
102
103 if (!clk)
104 return -EINVAL;
105
106 hw = __clk_get_hw(clk);
107
108 if (omap2_clk_is_hw_omap(hw)) {
109 struct clk_hw_omap *c = to_clk_hw_omap(hw);
110
111 return _omap2_clk_allow_idle(clk: c);
112 }
113
114 return -EINVAL;
115}
116
117static void _allow_autoidle(struct clk_ti_autoidle *clk)
118{
119 u32 val;
120
121 val = ti_clk_ll_ops->clk_readl(&clk->reg);
122
123 if (clk->flags & AUTOIDLE_LOW)
124 val &= ~(1 << clk->shift);
125 else
126 val |= (1 << clk->shift);
127
128 ti_clk_ll_ops->clk_writel(val, &clk->reg);
129}
130
131static void _deny_autoidle(struct clk_ti_autoidle *clk)
132{
133 u32 val;
134
135 val = ti_clk_ll_ops->clk_readl(&clk->reg);
136
137 if (clk->flags & AUTOIDLE_LOW)
138 val |= (1 << clk->shift);
139 else
140 val &= ~(1 << clk->shift);
141
142 ti_clk_ll_ops->clk_writel(val, &clk->reg);
143}
144
145/**
146 * _clk_generic_allow_autoidle_all - enable autoidle for all clocks
147 *
148 * Enables hardware autoidle for all registered DT clocks, which have
149 * the feature.
150 */
151static void _clk_generic_allow_autoidle_all(void)
152{
153 struct clk_ti_autoidle *c;
154
155 list_for_each_entry(c, &autoidle_clks, node)
156 _allow_autoidle(clk: c);
157}
158
159/**
160 * _clk_generic_deny_autoidle_all - disable autoidle for all clocks
161 *
162 * Disables hardware autoidle for all registered DT clocks, which have
163 * the feature.
164 */
165static void _clk_generic_deny_autoidle_all(void)
166{
167 struct clk_ti_autoidle *c;
168
169 list_for_each_entry(c, &autoidle_clks, node)
170 _deny_autoidle(clk: c);
171}
172
173/**
174 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
175 * @node: pointer to the clock device node
176 *
177 * Checks if a clock has hardware autoidle support or not (check
178 * for presence of 'ti,autoidle-shift' property in the device tree
179 * node) and sets up the hardware autoidle feature for the clock
180 * if available. If autoidle is available, the clock is also added
181 * to the autoidle list for later processing. Returns 0 on success,
182 * negative error value on failure.
183 */
184int __init of_ti_clk_autoidle_setup(struct device_node *node)
185{
186 u32 shift;
187 struct clk_ti_autoidle *clk;
188 int ret;
189
190 /* Check if this clock has autoidle support or not */
191 if (of_property_read_u32(np: node, propname: "ti,autoidle-shift", out_value: &shift))
192 return 0;
193
194 clk = kzalloc(size: sizeof(*clk), GFP_KERNEL);
195
196 if (!clk)
197 return -ENOMEM;
198
199 clk->shift = shift;
200 clk->name = ti_dt_clk_name(np: node);
201 ret = ti_clk_get_reg_addr(node, index: 0, reg: &clk->reg);
202 if (ret) {
203 kfree(objp: clk);
204 return ret;
205 }
206
207 if (of_property_read_bool(np: node, propname: "ti,invert-autoidle-bit"))
208 clk->flags |= AUTOIDLE_LOW;
209
210 list_add(new: &clk->node, head: &autoidle_clks);
211
212 return 0;
213}
214
215/**
216 * omap2_clk_enable_autoidle_all - enable autoidle on all OMAP clocks that
217 * support it
218 *
219 * Enable clock autoidle on all OMAP clocks that have allow_idle
220 * function pointers associated with them. This function is intended
221 * to be temporary until support for this is added to the common clock
222 * code. Returns 0.
223 */
224int omap2_clk_enable_autoidle_all(void)
225{
226 int ret;
227
228 ret = omap2_clk_for_each(fn: _omap2_clk_allow_idle);
229 if (ret)
230 return ret;
231
232 _clk_generic_allow_autoidle_all();
233
234 return 0;
235}
236
237/**
238 * omap2_clk_disable_autoidle_all - disable autoidle on all OMAP clocks that
239 * support it
240 *
241 * Disable clock autoidle on all OMAP clocks that have allow_idle
242 * function pointers associated with them. This function is intended
243 * to be temporary until support for this is added to the common clock
244 * code. Returns 0.
245 */
246int omap2_clk_disable_autoidle_all(void)
247{
248 int ret;
249
250 ret = omap2_clk_for_each(fn: _omap2_clk_deny_idle);
251 if (ret)
252 return ret;
253
254 _clk_generic_deny_autoidle_all();
255
256 return 0;
257}
258

source code of linux/drivers/clk/ti/autoidle.c