1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Cirrus Logic CLPS711X clocksource driver
4 *
5 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
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(sizeof(*clkevt), GFP_KERNEL);
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
82	if (!base)
83		return -ENOMEM;
84	if (!irq)
85		return -EINVAL;
86	if (IS_ERR(clock))
87		return PTR_ERR(clock);
88
89	switch (of_alias_get_id(np, "timer")) {
90	case CLPS711X_CLKSRC_CLOCKSOURCE:
91		clps711x_clksrc_init(clock, base);
92		break;
93	case CLPS711X_CLKSRC_CLOCKEVENT:
94		return _clps711x_clkevt_init(clock, base, irq);
95	default:
96		return -EINVAL;
97	}
98
99	return 0;
100}
101TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);
102