126 lines
2.9 KiB
C
126 lines
2.9 KiB
C
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/*
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* Cirrus Logic CLPS711X clocksource driver
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*
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* Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/sched_clock.h>
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#include <linux/slab.h>
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enum {
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CLPS711X_CLKSRC_CLOCKSOURCE,
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CLPS711X_CLKSRC_CLOCKEVENT,
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};
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static void __iomem *tcd;
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static u64 notrace clps711x_sched_clock_read(void)
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{
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return ~readw(tcd);
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}
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static int __init _clps711x_clksrc_init(struct clk *clock, void __iomem *base)
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{
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unsigned long rate;
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if (!base)
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return -ENOMEM;
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if (IS_ERR(clock))
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return PTR_ERR(clock);
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rate = clk_get_rate(clock);
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tcd = base;
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clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
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clocksource_mmio_readw_down);
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sched_clock_register(clps711x_sched_clock_read, 16, rate);
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return 0;
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}
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static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evt = dev_id;
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
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unsigned int irq)
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{
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struct clock_event_device *clkevt;
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unsigned long rate;
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if (!irq)
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return -EINVAL;
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if (!base)
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return -ENOMEM;
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if (IS_ERR(clock))
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return PTR_ERR(clock);
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clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
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if (!clkevt)
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return -ENOMEM;
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rate = clk_get_rate(clock);
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/* Set Timer prescaler */
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writew(DIV_ROUND_CLOSEST(rate, HZ), base);
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clkevt->name = "clps711x-clockevent";
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clkevt->rating = 300;
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clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
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clkevt->cpumask = cpumask_of(0);
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clockevents_config_and_register(clkevt, HZ, 0, 0);
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return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
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"clps711x-timer", clkevt);
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}
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void __init clps711x_clksrc_init(void __iomem *tc1_base, void __iomem *tc2_base,
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unsigned int irq)
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{
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struct clk *tc1 = clk_get_sys("clps711x-timer.0", NULL);
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struct clk *tc2 = clk_get_sys("clps711x-timer.1", NULL);
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BUG_ON(_clps711x_clksrc_init(tc1, tc1_base));
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BUG_ON(_clps711x_clkevt_init(tc2, tc2_base, irq));
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}
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#ifdef CONFIG_CLKSRC_OF
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static void __init clps711x_timer_init(struct device_node *np)
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{
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unsigned int irq = irq_of_parse_and_map(np, 0);
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struct clk *clock = of_clk_get(np, 0);
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void __iomem *base = of_iomap(np, 0);
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switch (of_alias_get_id(np, "timer")) {
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case CLPS711X_CLKSRC_CLOCKSOURCE:
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BUG_ON(_clps711x_clksrc_init(clock, base));
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break;
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case CLPS711X_CLKSRC_CLOCKEVENT:
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BUG_ON(_clps711x_clkevt_init(clock, base, irq));
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break;
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default:
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break;
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}
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}
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CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init);
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#endif
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