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/mod_devicetable.h> 17 #include <linux/err.h> 18 #include <linux/kernel.h> 19 #include <linux/platform_device.h> 20 #include <linux/watchdog.h> 21 #include <linux/moduleparam.h> 22 23 #define REG_COUNT 0x4 24 #define REG_MODE 0x8 25 #define REG_ENABLE 0xC 26 27 struct moxart_wdt_dev { 28 struct watchdog_device dev; 29 void __iomem *base; 30 unsigned int clock_frequency; 31 }; 32 33 static int heartbeat; 34 35 static int moxart_wdt_restart(struct watchdog_device *wdt_dev, 36 unsigned long action, void *data) 37 { 38 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 39 40 writel(1, moxart_wdt->base + REG_COUNT); 41 writel(0x5ab9, moxart_wdt->base + REG_MODE); 42 writel(0x03, moxart_wdt->base + REG_ENABLE); 43 44 return 0; 45 } 46 47 static int moxart_wdt_stop(struct watchdog_device *wdt_dev) 48 { 49 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 50 51 writel(0, moxart_wdt->base + REG_ENABLE); 52 53 return 0; 54 } 55 56 static int moxart_wdt_start(struct watchdog_device *wdt_dev) 57 { 58 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 59 60 writel(moxart_wdt->clock_frequency * wdt_dev->timeout, 61 moxart_wdt->base + REG_COUNT); 62 writel(0x5ab9, moxart_wdt->base + REG_MODE); 63 writel(0x03, moxart_wdt->base + REG_ENABLE); 64 65 return 0; 66 } 67 68 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, 69 unsigned int timeout) 70 { 71 wdt_dev->timeout = timeout; 72 73 return 0; 74 } 75 76 static const struct watchdog_info moxart_wdt_info = { 77 .identity = "moxart-wdt", 78 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 79 WDIOF_MAGICCLOSE, 80 }; 81 82 static const struct watchdog_ops moxart_wdt_ops = { 83 .owner = THIS_MODULE, 84 .start = moxart_wdt_start, 85 .stop = moxart_wdt_stop, 86 .set_timeout = moxart_wdt_set_timeout, 87 .restart = moxart_wdt_restart, 88 }; 89 90 static int moxart_wdt_probe(struct platform_device *pdev) 91 { 92 struct moxart_wdt_dev *moxart_wdt; 93 struct device *dev = &pdev->dev; 94 struct clk *clk; 95 int err; 96 unsigned int max_timeout; 97 bool nowayout = WATCHDOG_NOWAYOUT; 98 99 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); 100 if (!moxart_wdt) 101 return -ENOMEM; 102 103 platform_set_drvdata(pdev, moxart_wdt); 104 105 moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0); 106 if (IS_ERR(moxart_wdt->base)) 107 return PTR_ERR(moxart_wdt->base); 108 109 clk = devm_clk_get(dev, NULL); 110 if (IS_ERR(clk)) { 111 pr_err("%s: of_clk_get failed\n", __func__); 112 return PTR_ERR(clk); 113 } 114 115 moxart_wdt->clock_frequency = clk_get_rate(clk); 116 if (moxart_wdt->clock_frequency == 0) { 117 pr_err("%s: incorrect clock frequency\n", __func__); 118 return -EINVAL; 119 } 120 121 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 122 123 moxart_wdt->dev.info = &moxart_wdt_info; 124 moxart_wdt->dev.ops = &moxart_wdt_ops; 125 moxart_wdt->dev.timeout = max_timeout; 126 moxart_wdt->dev.min_timeout = 1; 127 moxart_wdt->dev.max_timeout = max_timeout; 128 moxart_wdt->dev.parent = dev; 129 130 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 131 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 132 watchdog_set_restart_priority(&moxart_wdt->dev, 128); 133 134 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 135 136 watchdog_stop_on_unregister(&moxart_wdt->dev); 137 err = devm_watchdog_register_device(dev, &moxart_wdt->dev); 138 if (err) 139 return err; 140 141 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", 142 moxart_wdt->dev.timeout, nowayout); 143 144 return 0; 145 } 146 147 static const struct of_device_id moxart_watchdog_match[] = { 148 { .compatible = "moxa,moxart-watchdog" }, 149 { }, 150 }; 151 MODULE_DEVICE_TABLE(of, moxart_watchdog_match); 152 153 static struct platform_driver moxart_wdt_driver = { 154 .probe = moxart_wdt_probe, 155 .driver = { 156 .name = "moxart-watchdog", 157 .of_match_table = moxart_watchdog_match, 158 }, 159 }; 160 module_platform_driver(moxart_wdt_driver); 161 162 module_param(heartbeat, int, 0); 163 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 164 165 MODULE_DESCRIPTION("MOXART watchdog driver"); 166 MODULE_LICENSE("GPL"); 167 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 168