1/*
2 *  Cirrus Logic CLPS711X clocksource driver
3 *
4 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12#include <linux/clk.h>
13#include <linux/clockchips.h>
14#include <linux/clocksource.h>
15#include <linux/interrupt.h>
16#include <linux/io.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19#include <linux/sched_clock.h>
20#include <linux/slab.h>
21
22enum {
23	CLPS711X_CLKSRC_CLOCKSOURCE,
24	CLPS711X_CLKSRC_CLOCKEVENT,
25};
26
27static void __iomem *tcd;
28
29static u64 notrace clps711x_sched_clock_read(void)
30{
31	return ~readw(tcd);
32}
33
34static int __init _clps711x_clksrc_init(struct clk *clock, void __iomem *base)
35{
36	unsigned long rate;
37
38	if (!base)
39		return -ENOMEM;
40	if (IS_ERR(clock))
41		return PTR_ERR(clock);
42
43	rate = clk_get_rate(clock);
44
45	tcd = base;
46
47	clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
48			      clocksource_mmio_readw_down);
49
50	sched_clock_register(clps711x_sched_clock_read, 16, rate);
51
52	return 0;
53}
54
55static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
56{
57	struct clock_event_device *evt = dev_id;
58
59	evt->event_handler(evt);
60
61	return IRQ_HANDLED;
62}
63
64static void clps711x_clockevent_set_mode(enum clock_event_mode mode,
65					 struct clock_event_device *evt)
66{
67}
68
69static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
70					unsigned int irq)
71{
72	struct clock_event_device *clkevt;
73	unsigned long rate;
74
75	if (!irq)
76		return -EINVAL;
77	if (!base)
78		return -ENOMEM;
79	if (IS_ERR(clock))
80		return PTR_ERR(clock);
81
82	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
83	if (!clkevt)
84		return -ENOMEM;
85
86	rate = clk_get_rate(clock);
87
88	/* Set Timer prescaler */
89	writew(DIV_ROUND_CLOSEST(rate, HZ), base);
90
91	clkevt->name = "clps711x-clockevent";
92	clkevt->rating = 300;
93	clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
94	clkevt->set_mode = clps711x_clockevent_set_mode;
95	clkevt->cpumask = cpumask_of(0);
96	clockevents_config_and_register(clkevt, HZ, 0, 0);
97
98	return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
99			   "clps711x-timer", clkevt);
100}
101
102void __init clps711x_clksrc_init(void __iomem *tc1_base, void __iomem *tc2_base,
103				 unsigned int irq)
104{
105	struct clk *tc1 = clk_get_sys("clps711x-timer.0", NULL);
106	struct clk *tc2 = clk_get_sys("clps711x-timer.1", NULL);
107
108	BUG_ON(_clps711x_clksrc_init(tc1, tc1_base));
109	BUG_ON(_clps711x_clkevt_init(tc2, tc2_base, irq));
110}
111
112#ifdef CONFIG_CLKSRC_OF
113static void __init clps711x_timer_init(struct device_node *np)
114{
115	unsigned int irq = irq_of_parse_and_map(np, 0);
116	struct clk *clock = of_clk_get(np, 0);
117	void __iomem *base = of_iomap(np, 0);
118
119	switch (of_alias_get_id(np, "timer")) {
120	case CLPS711X_CLKSRC_CLOCKSOURCE:
121		BUG_ON(_clps711x_clksrc_init(clock, base));
122		break;
123	case CLPS711X_CLKSRC_CLOCKEVENT:
124		BUG_ON(_clps711x_clkevt_init(clock, base, irq));
125		break;
126	default:
127		break;
128	}
129}
130CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init);
131#endif
132