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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Cirrus Logic CLPS711X clocksource driver4 *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