281 lines
6.3 KiB
C
281 lines
6.3 KiB
C
/*
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* Driver for Atmel SAMA5D4 Watchdog Timer
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*
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* Copyright (C) 2015 Atmel Corporation
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*
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* Licensed under GPLv2.
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*/
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/platform_device.h>
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#include <linux/reboot.h>
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#include <linux/watchdog.h>
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#include "at91sam9_wdt.h"
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/* minimum and maximum watchdog timeout, in seconds */
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#define MIN_WDT_TIMEOUT 1
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#define MAX_WDT_TIMEOUT 16
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#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
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#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
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struct sama5d4_wdt {
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struct watchdog_device wdd;
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void __iomem *reg_base;
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u32 config;
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};
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static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(wdt_timeout, int, 0);
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MODULE_PARM_DESC(wdt_timeout,
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"Watchdog timeout in seconds. (default = "
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__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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#define wdt_read(wdt, field) \
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readl_relaxed((wdt)->reg_base + (field))
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#define wdt_write(wtd, field, val) \
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writel_relaxed((val), (wdt)->reg_base + (field))
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static int sama5d4_wdt_start(struct watchdog_device *wdd)
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{
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struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
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u32 reg;
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reg = wdt_read(wdt, AT91_WDT_MR);
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reg &= ~AT91_WDT_WDDIS;
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wdt_write(wdt, AT91_WDT_MR, reg);
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return 0;
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}
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static int sama5d4_wdt_stop(struct watchdog_device *wdd)
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{
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struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
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u32 reg;
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reg = wdt_read(wdt, AT91_WDT_MR);
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reg |= AT91_WDT_WDDIS;
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wdt_write(wdt, AT91_WDT_MR, reg);
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return 0;
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}
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static int sama5d4_wdt_ping(struct watchdog_device *wdd)
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{
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struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
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wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
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return 0;
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}
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static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
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u32 value = WDT_SEC2TICKS(timeout);
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u32 reg;
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reg = wdt_read(wdt, AT91_WDT_MR);
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reg &= ~AT91_WDT_WDV;
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reg &= ~AT91_WDT_WDD;
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reg |= AT91_WDT_SET_WDV(value);
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reg |= AT91_WDT_SET_WDD(value);
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wdt_write(wdt, AT91_WDT_MR, reg);
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wdd->timeout = timeout;
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return 0;
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}
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static const struct watchdog_info sama5d4_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
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.identity = "Atmel SAMA5D4 Watchdog",
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};
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static struct watchdog_ops sama5d4_wdt_ops = {
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.owner = THIS_MODULE,
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.start = sama5d4_wdt_start,
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.stop = sama5d4_wdt_stop,
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.ping = sama5d4_wdt_ping,
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.set_timeout = sama5d4_wdt_set_timeout,
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};
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static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
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{
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struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
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if (wdt_read(wdt, AT91_WDT_SR)) {
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pr_crit("Atmel Watchdog Software Reset\n");
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emergency_restart();
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pr_crit("Reboot didn't succeed\n");
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}
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return IRQ_HANDLED;
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}
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static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
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{
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const char *tmp;
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wdt->config = AT91_WDT_WDDIS;
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if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
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!strcmp(tmp, "software"))
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wdt->config |= AT91_WDT_WDFIEN;
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else
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wdt->config |= AT91_WDT_WDRSTEN;
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if (of_property_read_bool(np, "atmel,idle-halt"))
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wdt->config |= AT91_WDT_WDIDLEHLT;
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if (of_property_read_bool(np, "atmel,dbg-halt"))
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wdt->config |= AT91_WDT_WDDBGHLT;
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return 0;
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}
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static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
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{
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struct watchdog_device *wdd = &wdt->wdd;
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u32 value = WDT_SEC2TICKS(wdd->timeout);
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u32 reg;
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/*
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* Because the fields WDV and WDD must not be modified when the WDDIS
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* bit is set, so clear the WDDIS bit before writing the WDT_MR.
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*/
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reg = wdt_read(wdt, AT91_WDT_MR);
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reg &= ~AT91_WDT_WDDIS;
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wdt_write(wdt, AT91_WDT_MR, reg);
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reg = wdt->config;
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reg |= AT91_WDT_SET_WDD(value);
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reg |= AT91_WDT_SET_WDV(value);
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wdt_write(wdt, AT91_WDT_MR, reg);
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return 0;
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}
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static int sama5d4_wdt_probe(struct platform_device *pdev)
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{
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struct watchdog_device *wdd;
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struct sama5d4_wdt *wdt;
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struct resource *res;
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void __iomem *regs;
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u32 irq = 0;
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int ret;
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wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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wdd = &wdt->wdd;
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wdd->timeout = wdt_timeout;
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wdd->info = &sama5d4_wdt_info;
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wdd->ops = &sama5d4_wdt_ops;
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wdd->min_timeout = MIN_WDT_TIMEOUT;
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wdd->max_timeout = MAX_WDT_TIMEOUT;
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watchdog_set_drvdata(wdd, wdt);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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regs = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(regs))
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return PTR_ERR(regs);
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wdt->reg_base = regs;
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if (pdev->dev.of_node) {
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irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
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if (!irq)
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dev_warn(&pdev->dev, "failed to get IRQ from DT\n");
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ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt);
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if (ret)
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return ret;
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}
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if ((wdt->config & AT91_WDT_WDFIEN) && irq) {
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ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
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IRQF_SHARED | IRQF_IRQPOLL |
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IRQF_NO_SUSPEND, pdev->name, pdev);
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if (ret) {
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dev_err(&pdev->dev,
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"cannot register interrupt handler\n");
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return ret;
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}
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}
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ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev);
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if (ret) {
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dev_err(&pdev->dev, "unable to set timeout value\n");
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return ret;
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}
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ret = sama5d4_wdt_init(wdt);
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if (ret)
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return ret;
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watchdog_set_nowayout(wdd, nowayout);
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ret = watchdog_register_device(wdd);
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if (ret) {
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dev_err(&pdev->dev, "failed to register watchdog device\n");
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return ret;
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}
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platform_set_drvdata(pdev, wdt);
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dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d)\n",
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wdt_timeout, nowayout);
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return 0;
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}
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static int sama5d4_wdt_remove(struct platform_device *pdev)
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{
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struct sama5d4_wdt *wdt = platform_get_drvdata(pdev);
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sama5d4_wdt_stop(&wdt->wdd);
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watchdog_unregister_device(&wdt->wdd);
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return 0;
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}
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static const struct of_device_id sama5d4_wdt_of_match[] = {
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{ .compatible = "atmel,sama5d4-wdt", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
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static struct platform_driver sama5d4_wdt_driver = {
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.probe = sama5d4_wdt_probe,
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.remove = sama5d4_wdt_remove,
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.driver = {
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.name = "sama5d4_wdt",
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.of_match_table = sama5d4_wdt_of_match,
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}
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};
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module_platform_driver(sama5d4_wdt_driver);
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MODULE_AUTHOR("Atmel Corporation");
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MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
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MODULE_LICENSE("GPL v2");
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