LXR linux/drivers/clocksource/clps711x-timer.c

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