1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MOXA ART SoCs watchdog driver. 4 * 5 * Copyright (C) 2013 Jonas Jensen 6 * 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 0x4 22 #define REG_MODE 0x8 23 #define REG_ENABLE 0xC 24 25 struct moxart_wdt_dev { 26 struct watchdog_device dev; 27 void __iomem *base; 28 unsigned int clock_frequency; 29 }; 30 31 static int heartbeat; 32 33 static 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 45 static 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 54 static 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 66 static 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 74 static const struct watchdog_info moxart_wdt_info = { 75 .identity = "moxart-wdt", 76 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 77 WDIOF_MAGICCLOSE, 78 }; 79 80 static 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 88 static 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 } 144 145 static const struct of_device_id moxart_watchdog_match[] = { 146 { .compatible = "moxa,moxart-watchdog" }, 147 { }, 148 }; 149 MODULE_DEVICE_TABLE(of, moxart_watchdog_match); 150 151 static 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 }; 158 module_platform_driver(moxart_wdt_driver); 159 160 module_param(heartbeat, int, 0); 161 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 162 163 MODULE_DESCRIPTION("MOXART watchdog driver"); 164 MODULE_LICENSE("GPL"); 165 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 166