7b8f10da3b
The initialisation of the efm32 clocksource first sets up the irq and only after that initialises the data needed for irq handling. In case this initialisation is delayed the irq handler would dereference a NULL pointer. I'm not aware of anything that could delay the process in such a way, but it's better to be safe than sorry, so setup the irq only when the clock event device is ready. Cc: stable@vger.kernel.org Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Yongbae Park <yongbae2@gmail.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
277 lines
6.5 KiB
C
277 lines
6.5 KiB
C
/*
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* Copyright (C) 2013 Pengutronix
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* Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify it under
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* the terms of the GNU General Public License version 2 as published by the
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* Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/clocksource.h>
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#include <linux/clockchips.h>
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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#include <linux/of.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/clk.h>
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#define TIMERn_CTRL 0x00
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#define TIMERn_CTRL_PRESC(val) (((val) & 0xf) << 24)
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#define TIMERn_CTRL_PRESC_1024 TIMERn_CTRL_PRESC(10)
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#define TIMERn_CTRL_CLKSEL(val) (((val) & 0x3) << 16)
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#define TIMERn_CTRL_CLKSEL_PRESCHFPERCLK TIMERn_CTRL_CLKSEL(0)
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#define TIMERn_CTRL_OSMEN 0x00000010
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#define TIMERn_CTRL_MODE(val) (((val) & 0x3) << 0)
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#define TIMERn_CTRL_MODE_UP TIMERn_CTRL_MODE(0)
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#define TIMERn_CTRL_MODE_DOWN TIMERn_CTRL_MODE(1)
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#define TIMERn_CMD 0x04
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#define TIMERn_CMD_START 0x00000001
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#define TIMERn_CMD_STOP 0x00000002
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#define TIMERn_IEN 0x0c
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#define TIMERn_IF 0x10
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#define TIMERn_IFS 0x14
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#define TIMERn_IFC 0x18
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#define TIMERn_IRQ_UF 0x00000002
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#define TIMERn_TOP 0x1c
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#define TIMERn_CNT 0x24
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struct efm32_clock_event_ddata {
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struct clock_event_device evtdev;
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void __iomem *base;
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unsigned periodic_top;
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};
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static void efm32_clock_event_set_mode(enum clock_event_mode mode,
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struct clock_event_device *evtdev)
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{
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struct efm32_clock_event_ddata *ddata =
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container_of(evtdev, struct efm32_clock_event_ddata, evtdev);
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD);
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writel_relaxed(ddata->periodic_top, ddata->base + TIMERn_TOP);
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writel_relaxed(TIMERn_CTRL_PRESC_1024 |
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TIMERn_CTRL_CLKSEL_PRESCHFPERCLK |
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TIMERn_CTRL_MODE_DOWN,
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ddata->base + TIMERn_CTRL);
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writel_relaxed(TIMERn_CMD_START, ddata->base + TIMERn_CMD);
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD);
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writel_relaxed(TIMERn_CTRL_PRESC_1024 |
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TIMERn_CTRL_CLKSEL_PRESCHFPERCLK |
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TIMERn_CTRL_OSMEN |
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TIMERn_CTRL_MODE_DOWN,
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ddata->base + TIMERn_CTRL);
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break;
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD);
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break;
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case CLOCK_EVT_MODE_RESUME:
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break;
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}
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}
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static int efm32_clock_event_set_next_event(unsigned long evt,
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struct clock_event_device *evtdev)
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{
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struct efm32_clock_event_ddata *ddata =
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container_of(evtdev, struct efm32_clock_event_ddata, evtdev);
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writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD);
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writel_relaxed(evt, ddata->base + TIMERn_CNT);
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writel_relaxed(TIMERn_CMD_START, ddata->base + TIMERn_CMD);
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return 0;
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}
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static irqreturn_t efm32_clock_event_handler(int irq, void *dev_id)
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{
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struct efm32_clock_event_ddata *ddata = dev_id;
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writel_relaxed(TIMERn_IRQ_UF, ddata->base + TIMERn_IFC);
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ddata->evtdev.event_handler(&ddata->evtdev);
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return IRQ_HANDLED;
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}
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static struct efm32_clock_event_ddata clock_event_ddata = {
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.evtdev = {
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.name = "efm32 clockevent",
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.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_MODE_PERIODIC,
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.set_mode = efm32_clock_event_set_mode,
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.set_next_event = efm32_clock_event_set_next_event,
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.rating = 200,
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},
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};
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static struct irqaction efm32_clock_event_irq = {
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.name = "efm32 clockevent",
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.flags = IRQF_TIMER,
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.handler = efm32_clock_event_handler,
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.dev_id = &clock_event_ddata,
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};
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static int __init efm32_clocksource_init(struct device_node *np)
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{
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struct clk *clk;
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void __iomem *base;
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unsigned long rate;
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int ret;
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clk = of_clk_get(np, 0);
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if (IS_ERR(clk)) {
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ret = PTR_ERR(clk);
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pr_err("failed to get clock for clocksource (%d)\n", ret);
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goto err_clk_get;
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}
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ret = clk_prepare_enable(clk);
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if (ret) {
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pr_err("failed to enable timer clock for clocksource (%d)\n",
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ret);
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goto err_clk_enable;
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}
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rate = clk_get_rate(clk);
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base = of_iomap(np, 0);
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if (!base) {
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ret = -EADDRNOTAVAIL;
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pr_err("failed to map registers for clocksource\n");
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goto err_iomap;
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}
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writel_relaxed(TIMERn_CTRL_PRESC_1024 |
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TIMERn_CTRL_CLKSEL_PRESCHFPERCLK |
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TIMERn_CTRL_MODE_UP, base + TIMERn_CTRL);
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writel_relaxed(TIMERn_CMD_START, base + TIMERn_CMD);
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ret = clocksource_mmio_init(base + TIMERn_CNT, "efm32 timer",
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DIV_ROUND_CLOSEST(rate, 1024), 200, 16,
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clocksource_mmio_readl_up);
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if (ret) {
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pr_err("failed to init clocksource (%d)\n", ret);
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goto err_clocksource_init;
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}
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return 0;
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err_clocksource_init:
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iounmap(base);
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err_iomap:
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clk_disable_unprepare(clk);
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err_clk_enable:
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clk_put(clk);
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err_clk_get:
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return ret;
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}
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static int __init efm32_clockevent_init(struct device_node *np)
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{
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struct clk *clk;
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void __iomem *base;
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unsigned long rate;
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int irq;
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int ret;
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clk = of_clk_get(np, 0);
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if (IS_ERR(clk)) {
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ret = PTR_ERR(clk);
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pr_err("failed to get clock for clockevent (%d)\n", ret);
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goto err_clk_get;
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}
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ret = clk_prepare_enable(clk);
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if (ret) {
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pr_err("failed to enable timer clock for clockevent (%d)\n",
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ret);
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goto err_clk_enable;
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}
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rate = clk_get_rate(clk);
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base = of_iomap(np, 0);
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if (!base) {
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ret = -EADDRNOTAVAIL;
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pr_err("failed to map registers for clockevent\n");
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goto err_iomap;
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}
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irq = irq_of_parse_and_map(np, 0);
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if (!irq) {
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ret = -ENOENT;
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pr_err("failed to get irq for clockevent\n");
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goto err_get_irq;
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}
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writel_relaxed(TIMERn_IRQ_UF, base + TIMERn_IEN);
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clock_event_ddata.base = base;
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clock_event_ddata.periodic_top = DIV_ROUND_CLOSEST(rate, 1024 * HZ);
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clockevents_config_and_register(&clock_event_ddata.evtdev,
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DIV_ROUND_CLOSEST(rate, 1024),
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0xf, 0xffff);
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setup_irq(irq, &efm32_clock_event_irq);
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return 0;
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err_get_irq:
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iounmap(base);
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err_iomap:
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clk_disable_unprepare(clk);
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err_clk_enable:
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clk_put(clk);
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err_clk_get:
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return ret;
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}
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/*
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* This function asserts that we have exactly one clocksource and one
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* clock_event_device in the end.
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*/
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static void __init efm32_timer_init(struct device_node *np)
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{
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static int has_clocksource, has_clockevent;
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int ret;
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if (!has_clocksource) {
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ret = efm32_clocksource_init(np);
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if (!ret) {
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has_clocksource = 1;
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return;
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}
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}
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if (!has_clockevent) {
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ret = efm32_clockevent_init(np);
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if (!ret) {
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has_clockevent = 1;
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return;
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}
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}
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}
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CLOCKSOURCE_OF_DECLARE(efm32compat, "efm32,timer", efm32_timer_init);
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CLOCKSOURCE_OF_DECLARE(efm32, "energymicro,efm32-timer", efm32_timer_init);
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