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Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module which can be used as a watchdog. This IP provides a support for windowed watchdog mode, in which the watchdog must be petted within a certain time window. If it is petted either too soon, or too late, a watchdog error will be triggered. Signed-off-by: Tero Kristo <t-kristo@ti.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200312095808.19907-4-t-kristo@ti.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
256 lines
6.0 KiB
C
256 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Watchdog driver for the K3 RTI module
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*
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* (c) Copyright 2019-2020 Texas Instruments Inc.
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* All rights reserved.
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*/
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#include <linux/clk.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#define DEFAULT_HEARTBEAT 60
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/* Max heartbeat is calculated at 32kHz source clock */
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#define MAX_HEARTBEAT 1000
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/* Timer register set definition */
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#define RTIDWDCTRL 0x90
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#define RTIDWDPRLD 0x94
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#define RTIWDSTATUS 0x98
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#define RTIWDKEY 0x9c
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#define RTIDWDCNTR 0xa0
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#define RTIWWDRXCTRL 0xa4
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#define RTIWWDSIZECTRL 0xa8
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#define RTIWWDRX_NMI 0xa
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#define RTIWWDSIZE_50P 0x50
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#define WDENABLE_KEY 0xa98559da
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#define WDKEY_SEQ0 0xe51a
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#define WDKEY_SEQ1 0xa35c
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#define WDT_PRELOAD_SHIFT 13
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#define WDT_PRELOAD_MAX 0xfff
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#define DWDST BIT(1)
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static int heartbeat;
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/*
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* struct to hold data for each WDT device
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* @base - base io address of WD device
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* @freq - source clock frequency of WDT
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* @wdd - hold watchdog device as is in WDT core
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*/
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struct rti_wdt_device {
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void __iomem *base;
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unsigned long freq;
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struct watchdog_device wdd;
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};
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static int rti_wdt_start(struct watchdog_device *wdd)
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{
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u32 timer_margin;
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struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
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/* set timeout period */
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timer_margin = (u64)wdd->timeout * wdt->freq;
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timer_margin >>= WDT_PRELOAD_SHIFT;
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if (timer_margin > WDT_PRELOAD_MAX)
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timer_margin = WDT_PRELOAD_MAX;
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writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
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/*
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* RTI only supports a windowed mode, where the watchdog can only
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* be petted during the open window; not too early or not too late.
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* The HW configuration options only allow for the open window size
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* to be 50% or less than that; we obviouly want to configure the open
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* window as large as possible so we select the 50% option. To avoid
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* any glitches, we accommodate 5% safety margin also, so we setup
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* the min_hw_hearbeat at 55% of the timeout period.
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*/
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wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
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/* Generate NMI when wdt expires */
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writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
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/* Open window size 50%; this is the largest window size available */
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writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
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readl_relaxed(wdt->base + RTIWWDSIZECTRL);
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/* enable watchdog */
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writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
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return 0;
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}
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static int rti_wdt_ping(struct watchdog_device *wdd)
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{
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struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
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/* put watchdog in service state */
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writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
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/* put watchdog in active state */
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writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
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return 0;
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}
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static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
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{
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u64 timer_counter;
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u32 val;
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struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
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/* if timeout has occurred then return 0 */
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val = readl_relaxed(wdt->base + RTIWDSTATUS);
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if (val & DWDST)
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return 0;
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timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
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do_div(timer_counter, wdt->freq);
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return timer_counter;
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}
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static const struct watchdog_info rti_wdt_info = {
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.options = WDIOF_KEEPALIVEPING,
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.identity = "K3 RTI Watchdog",
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};
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static const struct watchdog_ops rti_wdt_ops = {
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.owner = THIS_MODULE,
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.start = rti_wdt_start,
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.ping = rti_wdt_ping,
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.get_timeleft = rti_wdt_get_timeleft,
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};
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static int rti_wdt_probe(struct platform_device *pdev)
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{
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int ret = 0;
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struct device *dev = &pdev->dev;
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struct resource *wdt_mem;
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struct watchdog_device *wdd;
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struct rti_wdt_device *wdt;
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struct clk *clk;
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wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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clk = clk_get(dev, NULL);
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if (IS_ERR(clk)) {
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if (PTR_ERR(clk) != -EPROBE_DEFER)
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dev_err(dev, "failed to get clock\n");
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return PTR_ERR(clk);
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}
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wdt->freq = clk_get_rate(clk);
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clk_put(clk);
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if (!wdt->freq) {
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dev_err(dev, "Failed to get fck rate.\n");
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return -EINVAL;
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}
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pm_runtime_enable(dev);
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ret = pm_runtime_get_sync(dev);
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if (ret) {
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if (ret != -EPROBE_DEFER)
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dev_err(&pdev->dev, "runtime pm failed\n");
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return ret;
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}
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platform_set_drvdata(pdev, wdt);
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wdd = &wdt->wdd;
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wdd->info = &rti_wdt_info;
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wdd->ops = &rti_wdt_ops;
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wdd->min_timeout = 1;
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wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
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wdt->freq * 1000;
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wdd->timeout = DEFAULT_HEARTBEAT;
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wdd->parent = dev;
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watchdog_init_timeout(wdd, heartbeat, dev);
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watchdog_set_drvdata(wdd, wdt);
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watchdog_set_nowayout(wdd, 1);
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watchdog_set_restart_priority(wdd, 128);
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wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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wdt->base = devm_ioremap_resource(dev, wdt_mem);
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if (IS_ERR(wdt->base)) {
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ret = PTR_ERR(wdt->base);
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goto err_iomap;
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}
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ret = watchdog_register_device(wdd);
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if (ret) {
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dev_err(dev, "cannot register watchdog device\n");
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goto err_iomap;
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}
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return 0;
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err_iomap:
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pm_runtime_put_sync(&pdev->dev);
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return ret;
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}
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static int rti_wdt_remove(struct platform_device *pdev)
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{
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struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
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watchdog_unregister_device(&wdt->wdd);
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pm_runtime_put(&pdev->dev);
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return 0;
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}
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static const struct of_device_id rti_wdt_of_match[] = {
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{ .compatible = "ti,j7-rti-wdt", },
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{},
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};
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MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
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static struct platform_driver rti_wdt_driver = {
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.driver = {
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.name = "rti-wdt",
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.of_match_table = rti_wdt_of_match,
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},
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.probe = rti_wdt_probe,
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.remove = rti_wdt_remove,
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};
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module_platform_driver(rti_wdt_driver);
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MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
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MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat,
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"Watchdog heartbeat period in seconds from 1 to "
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__MODULE_STRING(MAX_HEARTBEAT) ", default "
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__MODULE_STRING(DEFAULT_HEARTBEAT));
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:rti-wdt");
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