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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * MOXA ART SoCs watchdog driver.4 *5 * Copyright (C) 2013 Jonas Jensen6 *7 * Jonas Jensen <jonas.jensen@gmail.com>8 *9 */10 11#include <linux/clk.h>12#include <linux/io.h>13#include <linux/module.h>14#include <linux/mod_devicetable.h>15#include <linux/err.h>16#include <linux/kernel.h>17#include <linux/platform_device.h>18#include <linux/watchdog.h>19#include <linux/moduleparam.h>20 21#define REG_COUNT 0x422#define REG_MODE 0x823#define REG_ENABLE 0xC24 25struct moxart_wdt_dev {26 struct watchdog_device dev;27 void __iomem *base;28 unsigned int clock_frequency;29};30 31static int heartbeat;32 33static int moxart_wdt_restart(struct watchdog_device *wdt_dev,34 unsigned long action, void *data)35{36 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);37 38 writel(1, moxart_wdt->base + REG_COUNT);39 writel(0x5ab9, moxart_wdt->base + REG_MODE);40 writel(0x03, moxart_wdt->base + REG_ENABLE);41 42 return 0;43}44 45static int moxart_wdt_stop(struct watchdog_device *wdt_dev)46{47 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);48 49 writel(0, moxart_wdt->base + REG_ENABLE);50 51 return 0;52}53 54static int moxart_wdt_start(struct watchdog_device *wdt_dev)55{56 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);57 58 writel(moxart_wdt->clock_frequency * wdt_dev->timeout,59 moxart_wdt->base + REG_COUNT);60 writel(0x5ab9, moxart_wdt->base + REG_MODE);61 writel(0x03, moxart_wdt->base + REG_ENABLE);62 63 return 0;64}65 66static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,67 unsigned int timeout)68{69 wdt_dev->timeout = timeout;70 71 return 0;72}73 74static const struct watchdog_info moxart_wdt_info = {75 .identity = "moxart-wdt",76 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |77 WDIOF_MAGICCLOSE,78};79 80static const struct watchdog_ops moxart_wdt_ops = {81 .owner = THIS_MODULE,82 .start = moxart_wdt_start,83 .stop = moxart_wdt_stop,84 .set_timeout = moxart_wdt_set_timeout,85 .restart = moxart_wdt_restart,86};87 88static int moxart_wdt_probe(struct platform_device *pdev)89{90 struct moxart_wdt_dev *moxart_wdt;91 struct device *dev = &pdev->dev;92 struct clk *clk;93 int err;94 unsigned int max_timeout;95 bool nowayout = WATCHDOG_NOWAYOUT;96 97 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);98 if (!moxart_wdt)99 return -ENOMEM;100 101 platform_set_drvdata(pdev, moxart_wdt);102 103 moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0);104 if (IS_ERR(moxart_wdt->base))105 return PTR_ERR(moxart_wdt->base);106 107 clk = devm_clk_get(dev, NULL);108 if (IS_ERR(clk)) {109 pr_err("%s: of_clk_get failed\n", __func__);110 return PTR_ERR(clk);111 }112 113 moxart_wdt->clock_frequency = clk_get_rate(clk);114 if (moxart_wdt->clock_frequency == 0) {115 pr_err("%s: incorrect clock frequency\n", __func__);116 return -EINVAL;117 }118 119 max_timeout = UINT_MAX / moxart_wdt->clock_frequency;120 121 moxart_wdt->dev.info = &moxart_wdt_info;122 moxart_wdt->dev.ops = &moxart_wdt_ops;123 moxart_wdt->dev.timeout = max_timeout;124 moxart_wdt->dev.min_timeout = 1;125 moxart_wdt->dev.max_timeout = max_timeout;126 moxart_wdt->dev.parent = dev;127 128 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);129 watchdog_set_nowayout(&moxart_wdt->dev, nowayout);130 watchdog_set_restart_priority(&moxart_wdt->dev, 128);131 132 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);133 134 watchdog_stop_on_unregister(&moxart_wdt->dev);135 err = devm_watchdog_register_device(dev, &moxart_wdt->dev);136 if (err)137 return err;138 139 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",140 moxart_wdt->dev.timeout, nowayout);141 142 return 0;143}144 145static const struct of_device_id moxart_watchdog_match[] = {146 { .compatible = "moxa,moxart-watchdog" },147 { },148};149MODULE_DEVICE_TABLE(of, moxart_watchdog_match);150 151static struct platform_driver moxart_wdt_driver = {152 .probe = moxart_wdt_probe,153 .driver = {154 .name = "moxart-watchdog",155 .of_match_table = moxart_watchdog_match,156 },157};158module_platform_driver(moxart_wdt_driver);159 160module_param(heartbeat, int, 0);161MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");162 163MODULE_DESCRIPTION("MOXART watchdog driver");164MODULE_LICENSE("GPL");165MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");166