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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Cirrus Logic CLPS711X clocksource driver
4 *
5 * Copyright (C) 2014 Alexander Shiyan <[email protected]>
6 */
7
8#include <linux/clk.h>
9#include <linux/clockchips.h>
10#include <linux/clocksource.h>
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/of_address.h>
14#include <linux/of_irq.h>
15#include <linux/sched_clock.h>
16#include <linux/slab.h>
17
18enum {
19 CLPS711X_CLKSRC_CLOCKSOURCE,
20 CLPS711X_CLKSRC_CLOCKEVENT,
21};
22
23static void __iomem *tcd;
24
25static u64 notrace clps711x_sched_clock_read(void)
26{
27 return ~readw(tcd);
28}
29
30static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base)
31{
32 unsigned long rate = clk_get_rate(clock);
33
34 tcd = base;
35
36 clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
37 clocksource_mmio_readw_down);
38
39 sched_clock_register(clps711x_sched_clock_read, 16, rate);
40}
41
42static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
43{
44 struct clock_event_device *evt = dev_id;
45
46 evt->event_handler(evt);
47
48 return IRQ_HANDLED;
49}
50
51static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
52 unsigned int irq)
53{
54 struct clock_event_device *clkevt;
55 unsigned long rate;
56
57 clkevt = kzalloc_obj(*clkevt);
58 if (!clkevt)
59 return -ENOMEM;
60
61 rate = clk_get_rate(clock);
62
63 /* Set Timer prescaler */
64 writew(DIV_ROUND_CLOSEST(rate, HZ), base);
65
66 clkevt->name = "clps711x-clockevent";
67 clkevt->rating = 300;
68 clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
69 clkevt->cpumask = cpumask_of(0);
70 clockevents_config_and_register(clkevt, HZ, 0, 0);
71
72 return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
73 "clps711x-timer", clkevt);
74}
75
76static int __init clps711x_timer_init(struct device_node *np)
77{
78 unsigned int irq = irq_of_parse_and_map(np, 0);
79 struct clk *clock = of_clk_get(np, 0);
80 void __iomem *base = of_iomap(np, 0);
81 int ret = 0;
82
83 if (!base)
84 return -ENOMEM;
85 if (!irq) {
86 ret = -EINVAL;
87 goto unmap_io;
88 }
89 if (IS_ERR(clock)) {
90 ret = PTR_ERR(clock);
91 goto unmap_io;
92 }
93
94 switch (of_alias_get_id(np, "timer")) {
95 case CLPS711X_CLKSRC_CLOCKSOURCE:
96 clps711x_clksrc_init(clock, base);
97 return 0;
98 case CLPS711X_CLKSRC_CLOCKEVENT:
99 ret = _clps711x_clkevt_init(clock, base, irq);
100 break;
101 default:
102 ret = -EINVAL;
103 break;
104 }
105
106unmap_io:
107 iounmap(base);
108 return ret;
109}
110TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);