drivers/watchdog/loongson1_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/module.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/watchdog.h>
  10 #include <loongson1.h>
  11
  12 #define DEFAULT_HEARTBEAT       30
  13
  14 static bool nowayout = WATCHDOG_NOWAYOUT;
  15 module_param(nowayout, bool, 0444);
  16
  17 static unsigned int heartbeat;
  18 module_param(heartbeat, uint, 0444);
  19
  20 struct ls1x_wdt_drvdata {
  21         void __iomem *base;
  22         struct clk *clk;
  23         unsigned long clk_rate;
  24         struct watchdog_device wdt;
  25 };
  26
  27 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
  28 {
  29         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  30
  31         writel(0x1, drvdata->base + WDT_SET);
  32
  33         return 0;
  34 }
  35
  36 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
  37                                 unsigned int timeout)
  38 {
  39         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  40         unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
  41         unsigned int counts;
  42
  43         wdt_dev->timeout = timeout;
  44
  45         counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
  46         writel(counts, drvdata->base + WDT_TIMER);
  47
  48         return 0;
  49 }
  50
  51 static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
  52 {
  53         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  54
  55         writel(0x1, drvdata->base + WDT_EN);
  56
  57         return 0;
  58 }
  59
  60 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
  61 {
  62         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  63
  64         writel(0x0, drvdata->base + WDT_EN);
  65
  66         return 0;
  67 }
  68
  69 static const struct watchdog_info ls1x_wdt_info = {
  70         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  71         .identity = "Loongson1 Watchdog",
  72 };
  73
  74 static const struct watchdog_ops ls1x_wdt_ops = {
  75         .owner = THIS_MODULE,
  76         .start = ls1x_wdt_start,
  77         .stop = ls1x_wdt_stop,
  78         .ping = ls1x_wdt_ping,
  79         .set_timeout = ls1x_wdt_set_timeout,
  80 };
  81
  82 static void ls1x_clk_disable_unprepare(void *data)
  83 {
  84         clk_disable_unprepare(data);
  85 }
  86
  87 static int ls1x_wdt_probe(struct platform_device *pdev)
  88 {
  89         struct device *dev = &pdev->dev;
  90         struct ls1x_wdt_drvdata *drvdata;
  91         struct watchdog_device *ls1x_wdt;
  92         unsigned long clk_rate;
  93         int err;
  94
  95         drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
  96         if (!drvdata)
  97                 return -ENOMEM;
  98
  99         drvdata->base = devm_platform_ioremap_resource(pdev, 0);
 100         if (IS_ERR(drvdata->base))
 101                 return PTR_ERR(drvdata->base);
 102
 103         drvdata->clk = devm_clk_get(dev, pdev->name);
 104         if (IS_ERR(drvdata->clk))
 105                 return PTR_ERR(drvdata->clk);
 106
 107         err = clk_prepare_enable(drvdata->clk);
 108         if (err) {
 109                 dev_err(dev, "clk enable failed\n");
 110                 return err;
 111         }
 112         err = devm_add_action_or_reset(dev, ls1x_clk_disable_unprepare,
 113                                        drvdata->clk);
 114         if (err)
 115                 return err;
 116
 117         clk_rate = clk_get_rate(drvdata->clk);
 118         if (!clk_rate)
 119                 return -EINVAL;
 120         drvdata->clk_rate = clk_rate;
 121
 122         ls1x_wdt = &drvdata->wdt;
 123         ls1x_wdt->info = &ls1x_wdt_info;
 124         ls1x_wdt->ops = &ls1x_wdt_ops;
 125         ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
 126         ls1x_wdt->min_timeout = 1;
 127         ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
 128         ls1x_wdt->parent = dev;
 129
 130         watchdog_init_timeout(ls1x_wdt, heartbeat, dev);
 131         watchdog_set_nowayout(ls1x_wdt, nowayout);
 132         watchdog_set_drvdata(ls1x_wdt, drvdata);
 133
 134         err = devm_watchdog_register_device(dev, &drvdata->wdt);
 135         if (err)
 136                 return err;
 137
 138         platform_set_drvdata(pdev, drvdata);
 139
 140         dev_info(dev, "Loongson1 Watchdog driver registered\n");
 141
 142         return 0;
 143 }
 144
 145 static struct platform_driver ls1x_wdt_driver = {
 146         .probe = ls1x_wdt_probe,
 147         .driver = {
 148                 .name = "ls1x-wdt",
 149         },
 150 };
 151
 152 module_platform_driver(ls1x_wdt_driver);
 153
 154 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
 155 MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
 156 MODULE_LICENSE("GPL");