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_restart(struct watchdog_device *wdt_dev) 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 device_node *node = dev->of_node; 93 struct resource *res; 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 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 106 moxart_wdt->base = devm_ioremap_resource(dev, res); 107 if (IS_ERR(moxart_wdt->base)) 108 return PTR_ERR(moxart_wdt->base); 109 110 clk = of_clk_get(node, 0); 111 if (IS_ERR(clk)) { 112 pr_err("%s: of_clk_get failed\n", __func__); 113 return PTR_ERR(clk); 114 } 115 116 moxart_wdt->clock_frequency = clk_get_rate(clk); 117 if (moxart_wdt->clock_frequency == 0) { 118 pr_err("%s: incorrect clock frequency\n", __func__); 119 return -EINVAL; 120 } 121 122 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 123 124 moxart_wdt->dev.info = &moxart_wdt_info; 125 moxart_wdt->dev.ops = &moxart_wdt_ops; 126 moxart_wdt->dev.timeout = max_timeout; 127 moxart_wdt->dev.min_timeout = 1; 128 moxart_wdt->dev.max_timeout = max_timeout; 129 moxart_wdt->dev.parent = dev; 130 131 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 132 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 133 watchdog_set_restart_priority(&moxart_wdt->dev, 128); 134 135 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 136 137 err = watchdog_register_device(&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 int moxart_wdt_remove(struct platform_device *pdev) 148 { 149 struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); 150 151 moxart_wdt_stop(&moxart_wdt->dev); 152 153 return 0; 154 } 155 156 static const struct of_device_id moxart_watchdog_match[] = { 157 { .compatible = "moxa,moxart-watchdog" }, 158 { }, 159 }; 160 MODULE_DEVICE_TABLE(of, moxart_watchdog_match); 161 162 static struct platform_driver moxart_wdt_driver = { 163 .probe = moxart_wdt_probe, 164 .remove = moxart_wdt_remove, 165 .driver = { 166 .name = "moxart-watchdog", 167 .of_match_table = moxart_watchdog_match, 168 }, 169 }; 170 module_platform_driver(moxart_wdt_driver); 171 172 module_param(heartbeat, int, 0); 173 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 174 175 MODULE_DESCRIPTION("MOXART watchdog driver"); 176 MODULE_LICENSE("GPL"); 177 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 178