1 /* 2 * MOXA ART SoCs watchdog driver. 3 * 4 * Copyright (C) 2013 Jonas Jensen 5 * 6 * Jonas Jensen <jonas.jensen@gmail.com> 7 * 8 * This file is licensed under the terms of the GNU General Public 9 * License version 2. This program is licensed "as is" without any 10 * warranty of any kind, whether express or implied. 11 */ 12 13 #include <linux/clk.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/err.h> 17 #include <linux/kernel.h> 18 #include <linux/platform_device.h> 19 #include <linux/watchdog.h> 20 #include <linux/moduleparam.h> 21 22 #define REG_COUNT 0x4 23 #define REG_MODE 0x8 24 #define REG_ENABLE 0xC 25 26 struct moxart_wdt_dev { 27 struct watchdog_device dev; 28 void __iomem *base; 29 unsigned int clock_frequency; 30 }; 31 32 static int heartbeat; 33 34 static int moxart_wdt_stop(struct watchdog_device *wdt_dev) 35 { 36 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 37 38 writel(0, moxart_wdt->base + REG_ENABLE); 39 40 return 0; 41 } 42 43 static int moxart_wdt_start(struct watchdog_device *wdt_dev) 44 { 45 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 46 47 writel(moxart_wdt->clock_frequency * wdt_dev->timeout, 48 moxart_wdt->base + REG_COUNT); 49 writel(0x5ab9, moxart_wdt->base + REG_MODE); 50 writel(0x03, moxart_wdt->base + REG_ENABLE); 51 52 return 0; 53 } 54 55 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, 56 unsigned int timeout) 57 { 58 wdt_dev->timeout = timeout; 59 60 return 0; 61 } 62 63 static const struct watchdog_info moxart_wdt_info = { 64 .identity = "moxart-wdt", 65 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 66 WDIOF_MAGICCLOSE, 67 }; 68 69 static const struct watchdog_ops moxart_wdt_ops = { 70 .owner = THIS_MODULE, 71 .start = moxart_wdt_start, 72 .stop = moxart_wdt_stop, 73 .set_timeout = moxart_wdt_set_timeout, 74 }; 75 76 static int moxart_wdt_probe(struct platform_device *pdev) 77 { 78 struct moxart_wdt_dev *moxart_wdt; 79 struct device *dev = &pdev->dev; 80 struct device_node *node = dev->of_node; 81 struct resource *res; 82 struct clk *clk; 83 int err; 84 unsigned int max_timeout; 85 bool nowayout = WATCHDOG_NOWAYOUT; 86 87 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); 88 if (!moxart_wdt) 89 return -ENOMEM; 90 91 platform_set_drvdata(pdev, moxart_wdt); 92 93 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 94 moxart_wdt->base = devm_ioremap_resource(dev, res); 95 if (IS_ERR(moxart_wdt->base)) 96 return PTR_ERR(moxart_wdt->base); 97 98 clk = of_clk_get(node, 0); 99 if (IS_ERR(clk)) { 100 pr_err("%s: of_clk_get failed\n", __func__); 101 return PTR_ERR(clk); 102 } 103 104 moxart_wdt->clock_frequency = clk_get_rate(clk); 105 if (moxart_wdt->clock_frequency == 0) { 106 pr_err("%s: incorrect clock frequency\n", __func__); 107 return -EINVAL; 108 } 109 110 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 111 112 moxart_wdt->dev.info = &moxart_wdt_info; 113 moxart_wdt->dev.ops = &moxart_wdt_ops; 114 moxart_wdt->dev.timeout = max_timeout; 115 moxart_wdt->dev.min_timeout = 1; 116 moxart_wdt->dev.max_timeout = max_timeout; 117 moxart_wdt->dev.parent = dev; 118 119 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 120 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 121 122 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 123 124 err = watchdog_register_device(&moxart_wdt->dev); 125 if (err) 126 return err; 127 128 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", 129 moxart_wdt->dev.timeout, nowayout); 130 131 return 0; 132 } 133 134 static int moxart_wdt_remove(struct platform_device *pdev) 135 { 136 struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); 137 138 moxart_wdt_stop(&moxart_wdt->dev); 139 watchdog_unregister_device(&moxart_wdt->dev); 140 141 return 0; 142 } 143 144 static const struct of_device_id moxart_watchdog_match[] = { 145 { .compatible = "moxa,moxart-watchdog" }, 146 { }, 147 }; 148 149 static struct platform_driver moxart_wdt_driver = { 150 .probe = moxart_wdt_probe, 151 .remove = moxart_wdt_remove, 152 .driver = { 153 .name = "moxart-watchdog", 154 .owner = THIS_MODULE, 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