1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * MStar WDT driver 4 * 5 * Copyright (C) 2019 - 2021 Daniel Palmer 6 * Copyright (C) 2021 Romain Perier 7 * 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/io.h> 12 #include <linux/mod_devicetable.h> 13 #include <linux/module.h> 14 #include <linux/platform_device.h> 15 #include <linux/watchdog.h> 16 17 #define REG_WDT_CLR 0x0 18 #define REG_WDT_MAX_PRD_L 0x10 19 #define REG_WDT_MAX_PRD_H 0x14 20 21 #define MSC313E_WDT_MIN_TIMEOUT 1 22 #define MSC313E_WDT_DEFAULT_TIMEOUT 30 23 24 static unsigned int timeout; 25 26 module_param(timeout, int, 0); 27 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); 28 29 struct msc313e_wdt_priv { 30 void __iomem *base; 31 struct watchdog_device wdev; 32 struct clk *clk; 33 }; 34 35 static int msc313e_wdt_start(struct watchdog_device *wdev) 36 { 37 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); 38 u32 timeout; 39 int err; 40 41 err = clk_prepare_enable(priv->clk); 42 if (err) 43 return err; 44 45 timeout = wdev->timeout * clk_get_rate(priv->clk); 46 writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L); 47 writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H); 48 writew(1, priv->base + REG_WDT_CLR); 49 return 0; 50 } 51 52 static int msc313e_wdt_ping(struct watchdog_device *wdev) 53 { 54 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); 55 56 writew(1, priv->base + REG_WDT_CLR); 57 return 0; 58 } 59 60 static int msc313e_wdt_stop(struct watchdog_device *wdev) 61 { 62 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); 63 64 writew(0, priv->base + REG_WDT_MAX_PRD_L); 65 writew(0, priv->base + REG_WDT_MAX_PRD_H); 66 writew(0, priv->base + REG_WDT_CLR); 67 clk_disable_unprepare(priv->clk); 68 return 0; 69 } 70 71 static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time) 72 { 73 wdev->timeout = new_time; 74 75 return msc313e_wdt_start(wdev); 76 } 77 78 static const struct watchdog_info msc313e_wdt_ident = { 79 .identity = "MSC313e watchdog", 80 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, 81 }; 82 83 static const struct watchdog_ops msc313e_wdt_ops = { 84 .owner = THIS_MODULE, 85 .start = msc313e_wdt_start, 86 .stop = msc313e_wdt_stop, 87 .ping = msc313e_wdt_ping, 88 .set_timeout = msc313e_wdt_settimeout, 89 }; 90 91 static const struct of_device_id msc313e_wdt_of_match[] = { 92 { .compatible = "mstar,msc313e-wdt", }, 93 { /* sentinel */ } 94 }; 95 MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match); 96 97 static int msc313e_wdt_probe(struct platform_device *pdev) 98 { 99 struct device *dev = &pdev->dev; 100 struct msc313e_wdt_priv *priv; 101 102 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 103 if (!priv) 104 return -ENOMEM; 105 106 priv->base = devm_platform_ioremap_resource(pdev, 0); 107 if (IS_ERR(priv->base)) 108 return PTR_ERR(priv->base); 109 110 priv->clk = devm_clk_get(dev, NULL); 111 if (IS_ERR(priv->clk)) { 112 dev_err(dev, "No input clock\n"); 113 return PTR_ERR(priv->clk); 114 } 115 116 priv->wdev.info = &msc313e_wdt_ident, 117 priv->wdev.ops = &msc313e_wdt_ops, 118 priv->wdev.parent = dev; 119 priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT; 120 priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk); 121 priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT; 122 123 /* If the period is non-zero the WDT is running */ 124 if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16)) 125 set_bit(WDOG_HW_RUNNING, &priv->wdev.status); 126 127 watchdog_set_drvdata(&priv->wdev, priv); 128 129 watchdog_init_timeout(&priv->wdev, timeout, dev); 130 watchdog_stop_on_reboot(&priv->wdev); 131 watchdog_stop_on_unregister(&priv->wdev); 132 133 return devm_watchdog_register_device(dev, &priv->wdev); 134 } 135 136 static int __maybe_unused msc313e_wdt_suspend(struct device *dev) 137 { 138 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev); 139 140 if (watchdog_active(&priv->wdev)) 141 msc313e_wdt_stop(&priv->wdev); 142 143 return 0; 144 } 145 146 static int __maybe_unused msc313e_wdt_resume(struct device *dev) 147 { 148 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev); 149 150 if (watchdog_active(&priv->wdev)) 151 msc313e_wdt_start(&priv->wdev); 152 153 return 0; 154 } 155 156 static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume); 157 158 static struct platform_driver msc313e_wdt_driver = { 159 .driver = { 160 .name = "msc313e-wdt", 161 .of_match_table = msc313e_wdt_of_match, 162 .pm = &msc313e_wdt_pm_ops, 163 }, 164 .probe = msc313e_wdt_probe, 165 }; 166 module_platform_driver(msc313e_wdt_driver); 167 168 MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>"); 169 MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e"); 170 MODULE_LICENSE("GPL v2"); 171