266 lines
6.4 KiB
C
266 lines
6.4 KiB
C
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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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 version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/clk.h>
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#include <linux/delay.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/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/of_device.h>
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enum wdt_reg {
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WDT_RST,
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WDT_EN,
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WDT_STS,
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WDT_BARK_TIME,
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WDT_BITE_TIME,
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};
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static const u32 reg_offset_data_apcs_tmr[] = {
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[WDT_RST] = 0x38,
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[WDT_EN] = 0x40,
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[WDT_STS] = 0x44,
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[WDT_BARK_TIME] = 0x4C,
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[WDT_BITE_TIME] = 0x5C,
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};
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static const u32 reg_offset_data_kpss[] = {
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[WDT_RST] = 0x4,
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[WDT_EN] = 0x8,
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[WDT_STS] = 0xC,
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[WDT_BARK_TIME] = 0x10,
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[WDT_BITE_TIME] = 0x14,
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};
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struct qcom_wdt {
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struct watchdog_device wdd;
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struct clk *clk;
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unsigned long rate;
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void __iomem *base;
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const u32 *layout;
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};
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static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
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{
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return wdt->base + wdt->layout[reg];
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}
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static inline
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struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
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{
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return container_of(wdd, struct qcom_wdt, wdd);
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}
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static int qcom_wdt_start(struct watchdog_device *wdd)
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{
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struct qcom_wdt *wdt = to_qcom_wdt(wdd);
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writel(0, wdt_addr(wdt, WDT_EN));
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writel(1, wdt_addr(wdt, WDT_RST));
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writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
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writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
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writel(1, wdt_addr(wdt, WDT_EN));
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return 0;
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}
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static int qcom_wdt_stop(struct watchdog_device *wdd)
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{
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struct qcom_wdt *wdt = to_qcom_wdt(wdd);
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writel(0, wdt_addr(wdt, WDT_EN));
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return 0;
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}
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static int qcom_wdt_ping(struct watchdog_device *wdd)
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{
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struct qcom_wdt *wdt = to_qcom_wdt(wdd);
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writel(1, wdt_addr(wdt, WDT_RST));
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return 0;
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}
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static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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wdd->timeout = timeout;
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return qcom_wdt_start(wdd);
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}
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static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
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void *data)
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{
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struct qcom_wdt *wdt = to_qcom_wdt(wdd);
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u32 timeout;
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/*
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* Trigger watchdog bite:
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* Setup BITE_TIME to be 128ms, and enable WDT.
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*/
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timeout = 128 * wdt->rate / 1000;
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writel(0, wdt_addr(wdt, WDT_EN));
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writel(1, wdt_addr(wdt, WDT_RST));
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writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
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writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
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writel(1, wdt_addr(wdt, WDT_EN));
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/*
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* Actually make sure the above sequence hits hardware before sleeping.
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*/
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wmb();
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msleep(150);
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return 0;
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}
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static const struct watchdog_ops qcom_wdt_ops = {
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.start = qcom_wdt_start,
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.stop = qcom_wdt_stop,
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.ping = qcom_wdt_ping,
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.set_timeout = qcom_wdt_set_timeout,
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.restart = qcom_wdt_restart,
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.owner = THIS_MODULE,
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};
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static const struct watchdog_info qcom_wdt_info = {
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.options = WDIOF_KEEPALIVEPING
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| WDIOF_MAGICCLOSE
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| WDIOF_SETTIMEOUT
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| WDIOF_CARDRESET,
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.identity = KBUILD_MODNAME,
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};
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static int qcom_wdt_probe(struct platform_device *pdev)
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{
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struct qcom_wdt *wdt;
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struct resource *res;
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struct device_node *np = pdev->dev.of_node;
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const u32 *regs;
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u32 percpu_offset;
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int ret;
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regs = of_device_get_match_data(&pdev->dev);
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if (!regs) {
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dev_err(&pdev->dev, "Unsupported QCOM WDT module\n");
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return -ENODEV;
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}
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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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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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/* We use CPU0's DGT for the watchdog */
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if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
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percpu_offset = 0;
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res->start += percpu_offset;
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res->end += percpu_offset;
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wdt->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(wdt->base))
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return PTR_ERR(wdt->base);
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wdt->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(wdt->clk)) {
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dev_err(&pdev->dev, "failed to get input clock\n");
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return PTR_ERR(wdt->clk);
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}
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ret = clk_prepare_enable(wdt->clk);
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if (ret) {
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dev_err(&pdev->dev, "failed to setup clock\n");
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return ret;
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}
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/*
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* We use the clock rate to calculate the max timeout, so ensure it's
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* not zero to avoid a divide-by-zero exception.
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*
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* WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
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* that it would bite before a second elapses it's usefulness is
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* limited. Bail if this is the case.
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*/
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wdt->rate = clk_get_rate(wdt->clk);
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if (wdt->rate == 0 ||
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wdt->rate > 0x10000000U) {
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dev_err(&pdev->dev, "invalid clock rate\n");
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ret = -EINVAL;
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goto err_clk_unprepare;
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}
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wdt->wdd.info = &qcom_wdt_info;
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wdt->wdd.ops = &qcom_wdt_ops;
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wdt->wdd.min_timeout = 1;
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wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
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wdt->wdd.parent = &pdev->dev;
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wdt->layout = regs;
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if (readl(wdt->base + WDT_STS) & 1)
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wdt->wdd.bootstatus = WDIOF_CARDRESET;
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/*
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* If 'timeout-sec' unspecified in devicetree, assume a 30 second
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* default, unless the max timeout is less than 30 seconds, then use
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* the max instead.
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*/
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wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
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watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
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ret = watchdog_register_device(&wdt->wdd);
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if (ret) {
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dev_err(&pdev->dev, "failed to register watchdog\n");
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goto err_clk_unprepare;
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}
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platform_set_drvdata(pdev, wdt);
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return 0;
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err_clk_unprepare:
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clk_disable_unprepare(wdt->clk);
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return ret;
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}
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static int qcom_wdt_remove(struct platform_device *pdev)
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{
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struct qcom_wdt *wdt = platform_get_drvdata(pdev);
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watchdog_unregister_device(&wdt->wdd);
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clk_disable_unprepare(wdt->clk);
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return 0;
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}
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static const struct of_device_id qcom_wdt_of_table[] = {
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{ .compatible = "qcom,kpss-timer", .data = reg_offset_data_apcs_tmr },
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{ .compatible = "qcom,scss-timer", .data = reg_offset_data_apcs_tmr },
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{ .compatible = "qcom,kpss-wdt", .data = reg_offset_data_kpss },
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{ },
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};
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MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
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static struct platform_driver qcom_watchdog_driver = {
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.probe = qcom_wdt_probe,
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.remove = qcom_wdt_remove,
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.driver = {
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.name = KBUILD_MODNAME,
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.of_match_table = qcom_wdt_of_table,
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},
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};
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module_platform_driver(qcom_watchdog_driver);
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MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
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MODULE_LICENSE("GPL v2");
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