| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [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 | |
| 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_TIMER_OF |
| 107 | static int __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 | return _clps711x_clksrc_init(clock, base); |
| 116 | case CLPS711X_CLKSRC_CLOCKEVENT: |
| 117 | return _clps711x_clkevt_init(clock, base, irq); |
| 118 | default: |
| 119 | return -EINVAL; |
| 120 | } |
| 121 | } |
| 122 | TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init); |
| 123 | #endif |