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gerrit-public.fairphone.software / kernel / msm-4.9 / f0b7fabec3273c85fa2c4714762177d04f64c08e / . / drivers / clocksource / clps711x-timer.c
blob: d83ec1f2fddc9d8e04c8bc3f29cb7e8c9e6f6c77 [file] [log] [blame]
Alexander Shiyanf0b7fab2014-07-13 08:45:13 +0400[diff] [blame^]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