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Merge tag 'v4.3-rc3' into next
[karo-tx-linux.git] / drivers / clocksource / clps711x-timer.c
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
22 enum {
23         CLPS711X_CLKSRC_CLOCKSOURCE,
24         CLPS711X_CLKSRC_CLOCKEVENT,
25 };
26
27 static void __iomem *tcd;
28
29 static u64 notrace clps711x_sched_clock_read(void)
30 {
31         return ~readw(tcd);
32 }
33
34 static 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
55 static 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
64 static 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;
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
96 void __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
107 static 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 }
124 CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init);
125 #endif