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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Watchdog driver for TQMx86 PLD.4 *5 * The watchdog supports power of 2 timeouts from 1 to 4096sec.6 * Once started, it cannot be stopped.7 *8 * Based on the vendor code written by Vadim V.Vlasov9 * <vvlasov@dev.rtsoft.ru>10 */11 12#include <linux/io.h>13#include <linux/log2.h>14#include <linux/module.h>15#include <linux/platform_device.h>16#include <linux/timer.h>17#include <linux/watchdog.h>18 19/* default timeout (secs) */20#define WDT_TIMEOUT 3221 22static unsigned int timeout;23module_param(timeout, uint, 0);24MODULE_PARM_DESC(timeout,25 "Watchdog timeout in seconds. (1<=timeout<=4096, default="26 __MODULE_STRING(WDT_TIMEOUT) ")");27struct tqmx86_wdt {28 struct watchdog_device wdd;29 void __iomem *io_base;30};31 32#define TQMX86_WDCFG 0x00 /* Watchdog Configuration Register */33#define TQMX86_WDCS 0x01 /* Watchdog Config/Status Register */34 35static int tqmx86_wdt_start(struct watchdog_device *wdd)36{37 struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);38 39 iowrite8(0x81, priv->io_base + TQMX86_WDCS);40 41 return 0;42}43 44static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)45{46 struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);47 u8 val;48 49 t = roundup_pow_of_two(t);50 val = ilog2(t) | 0x90;51 val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */52 iowrite8(val, priv->io_base + TQMX86_WDCFG);53 54 wdd->timeout = t;55 56 return 0;57}58 59static const struct watchdog_info tqmx86_wdt_info = {60 .options = WDIOF_SETTIMEOUT |61 WDIOF_KEEPALIVEPING,62 .identity = "TQMx86 Watchdog",63};64 65static const struct watchdog_ops tqmx86_wdt_ops = {66 .owner = THIS_MODULE,67 .start = tqmx86_wdt_start,68 .set_timeout = tqmx86_wdt_set_timeout,69};70 71static int tqmx86_wdt_probe(struct platform_device *pdev)72{73 struct device *dev = &pdev->dev;74 struct tqmx86_wdt *priv;75 struct resource *res;76 int err;77 78 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);79 if (!priv)80 return -ENOMEM;81 82 res = platform_get_resource(pdev, IORESOURCE_IO, 0);83 if (!res)84 return -ENODEV;85 86 priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));87 if (!priv->io_base)88 return -ENOMEM;89 90 watchdog_set_drvdata(&priv->wdd, priv);91 92 priv->wdd.parent = dev;93 priv->wdd.info = &tqmx86_wdt_info;94 priv->wdd.ops = &tqmx86_wdt_ops;95 priv->wdd.min_timeout = 1;96 priv->wdd.max_timeout = 4096;97 priv->wdd.max_hw_heartbeat_ms = 4096*1000;98 priv->wdd.timeout = WDT_TIMEOUT;99 100 watchdog_init_timeout(&priv->wdd, timeout, dev);101 watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);102 103 tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);104 105 err = devm_watchdog_register_device(dev, &priv->wdd);106 if (err)107 return err;108 109 dev_info(dev, "TQMx86 watchdog\n");110 111 return 0;112}113 114static struct platform_driver tqmx86_wdt_driver = {115 .driver = {116 .name = "tqmx86-wdt",117 },118 .probe = tqmx86_wdt_probe,119};120 121module_platform_driver(tqmx86_wdt_driver);122 123MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");124MODULE_DESCRIPTION("TQMx86 Watchdog");125MODULE_ALIAS("platform:tqmx86-wdt");126MODULE_LICENSE("GPL");127