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 | |
18 | enum { |
19 | CLPS711X_CLKSRC_CLOCKSOURCE, |
20 | CLPS711X_CLKSRC_CLOCKEVENT, |
21 | }; |
22 | |
23 | static void __iomem *tcd; |
24 | |
25 | static u64 notrace clps711x_sched_clock_read(void) |
26 | { |
27 | return ~readw(addr: tcd); |
28 | } |
29 | |
30 | static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base) |
31 | { |
32 | unsigned long rate = clk_get_rate(clk: 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(read: clps711x_sched_clock_read, bits: 16, rate); |
40 | } |
41 | |
42 | static 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 | |
51 | static 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(size: sizeof(*clkevt), GFP_KERNEL); |
58 | if (!clkevt) |
59 | return -ENOMEM; |
60 | |
61 | rate = clk_get_rate(clk: clock); |
62 | |
63 | /* Set Timer prescaler */ |
64 | writew(DIV_ROUND_CLOSEST(rate, HZ), addr: 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(dev: clkevt, HZ, min_delta: 0, max_delta: 0); |
71 | |
72 | return request_irq(irq, handler: clps711x_timer_interrupt, IRQF_TIMER, |
73 | name: "clps711x-timer" , dev: clkevt); |
74 | } |
75 | |
76 | static int __init clps711x_timer_init(struct device_node *np) |
77 | { |
78 | unsigned int irq = irq_of_parse_and_map(node: np, index: 0); |
79 | struct clk *clock = of_clk_get(np, index: 0); |
80 | void __iomem *base = of_iomap(node: np, index: 0); |
81 | |
82 | if (!base) |
83 | return -ENOMEM; |
84 | if (!irq) |
85 | return -EINVAL; |
86 | if (IS_ERR(ptr: clock)) |
87 | return PTR_ERR(ptr: clock); |
88 | |
89 | switch (of_alias_get_id(np, stem: "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 | } |
101 | TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer" , clps711x_timer_init); |
102 | |