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gerrit-public.fairphone.software / kernel / msm-4.9 / 69aa40e276c79fc4d6b47b3126ce475aa3d09de1 / . / drivers / clocksource / clps711x-timer.c
blob: cdd86e3525bbb04107bb964c357f07d8588a934d [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
Alexander Shiyanf0b7fab2014-07-13 08:45:13 +0400[diff] [blame]64static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
65 unsigned int irq)
66{
67 struct clock_event_device *clkevt;
68 unsigned long rate;
69
70 if (!irq)
71 return -EINVAL;
72 if (!base)
73 return -ENOMEM;
74 if (IS_ERR(clock))
75 return PTR_ERR(clock);
76
77 clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
78 if (!clkevt)
79 return -ENOMEM;
80
81 rate = clk_get_rate(clock);
82
83 /* Set Timer prescaler */
84 writew(DIV_ROUND_CLOSEST(rate, HZ), base);
85
86 clkevt->name = "clps711x-clockevent";
87 clkevt->rating = 300;
88 clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
Alexander Shiyanf0b7fab2014-07-13 08:45:13 +0400[diff] [blame]89 clkevt->cpumask = cpumask_of(0);
90 clockevents_config_and_register(clkevt, HZ, 0, 0);
91
92 return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
93 "clps711x-timer", clkevt);
94}
95
96void __init clps711x_clksrc_init(void __iomem *tc1_base, void __iomem *tc2_base,
97 unsigned int irq)
98{
99 struct clk *tc1 = clk_get_sys("clps711x-timer.0", NULL);
100 struct clk *tc2 = clk_get_sys("clps711x-timer.1", NULL);
101
102 BUG_ON(_clps711x_clksrc_init(tc1, tc1_base));
103 BUG_ON(_clps711x_clkevt_init(tc2, tc2_base, irq));
104}
105
106#ifdef CONFIG_CLKSRC_OF
107static void __init clps711x_timer_init(struct device_node *np)
108{
109 unsigned int irq = irq_of_parse_and_map(np, 0);
110 struct clk *clock = of_clk_get(np, 0);
111 void __iomem *base = of_iomap(np, 0);
112
113 switch (of_alias_get_id(np, "timer")) {
114 case CLPS711X_CLKSRC_CLOCKSOURCE:
115 BUG_ON(_clps711x_clksrc_init(clock, base));
116 break;
117 case CLPS711X_CLKSRC_CLOCKEVENT:
118 BUG_ON(_clps711x_clkevt_init(clock, base, irq));
119 break;
120 default:
121 break;
122 }
123}
124CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init);
125#endif