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229 lines
5.5 KiB
229 lines
5.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* sl28cpld watchdog driver |
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* |
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* Copyright 2020 Kontron Europe GmbH |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/property.h> |
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#include <linux/regmap.h> |
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#include <linux/watchdog.h> |
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/* |
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* Watchdog timer block registers. |
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*/ |
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#define WDT_CTRL 0x00 |
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#define WDT_CTRL_EN BIT(0) |
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#define WDT_CTRL_LOCK BIT(2) |
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#define WDT_CTRL_ASSERT_SYS_RESET BIT(6) |
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#define WDT_CTRL_ASSERT_WDT_TIMEOUT BIT(7) |
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#define WDT_TIMEOUT 0x01 |
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#define WDT_KICK 0x02 |
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#define WDT_KICK_VALUE 0x6b |
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#define WDT_COUNT 0x03 |
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#define WDT_DEFAULT_TIMEOUT 10 |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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static int timeout; |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds"); |
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struct sl28cpld_wdt { |
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struct watchdog_device wdd; |
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struct regmap *regmap; |
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u32 offset; |
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bool assert_wdt_timeout; |
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}; |
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static int sl28cpld_wdt_ping(struct watchdog_device *wdd) |
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{ |
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struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd); |
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return regmap_write(wdt->regmap, wdt->offset + WDT_KICK, |
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WDT_KICK_VALUE); |
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} |
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static int sl28cpld_wdt_start(struct watchdog_device *wdd) |
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{ |
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struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd); |
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unsigned int val; |
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val = WDT_CTRL_EN | WDT_CTRL_ASSERT_SYS_RESET; |
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if (wdt->assert_wdt_timeout) |
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val |= WDT_CTRL_ASSERT_WDT_TIMEOUT; |
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if (nowayout) |
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val |= WDT_CTRL_LOCK; |
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return regmap_update_bits(wdt->regmap, wdt->offset + WDT_CTRL, |
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val, val); |
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} |
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static int sl28cpld_wdt_stop(struct watchdog_device *wdd) |
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{ |
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struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd); |
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return regmap_update_bits(wdt->regmap, wdt->offset + WDT_CTRL, |
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WDT_CTRL_EN, 0); |
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} |
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static unsigned int sl28cpld_wdt_get_timeleft(struct watchdog_device *wdd) |
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{ |
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struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd); |
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unsigned int val; |
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int ret; |
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ret = regmap_read(wdt->regmap, wdt->offset + WDT_COUNT, &val); |
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if (ret) |
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return 0; |
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return val; |
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} |
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static int sl28cpld_wdt_set_timeout(struct watchdog_device *wdd, |
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unsigned int timeout) |
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{ |
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struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd); |
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int ret; |
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ret = regmap_write(wdt->regmap, wdt->offset + WDT_TIMEOUT, timeout); |
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if (ret) |
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return ret; |
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wdd->timeout = timeout; |
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return 0; |
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} |
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static const struct watchdog_info sl28cpld_wdt_info = { |
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
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.identity = "sl28cpld watchdog", |
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}; |
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static struct watchdog_ops sl28cpld_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = sl28cpld_wdt_start, |
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.stop = sl28cpld_wdt_stop, |
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.ping = sl28cpld_wdt_ping, |
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.set_timeout = sl28cpld_wdt_set_timeout, |
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.get_timeleft = sl28cpld_wdt_get_timeleft, |
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}; |
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static int sl28cpld_wdt_probe(struct platform_device *pdev) |
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{ |
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struct watchdog_device *wdd; |
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struct sl28cpld_wdt *wdt; |
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unsigned int status; |
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unsigned int val; |
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int ret; |
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if (!pdev->dev.parent) |
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return -ENODEV; |
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wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); |
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if (!wdt) |
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return -ENOMEM; |
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wdt->regmap = dev_get_regmap(pdev->dev.parent, NULL); |
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if (!wdt->regmap) |
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return -ENODEV; |
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ret = device_property_read_u32(&pdev->dev, "reg", &wdt->offset); |
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if (ret) |
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return -EINVAL; |
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wdt->assert_wdt_timeout = device_property_read_bool(&pdev->dev, |
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"kontron,assert-wdt-timeout-pin"); |
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/* initialize struct watchdog_device */ |
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wdd = &wdt->wdd; |
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wdd->parent = &pdev->dev; |
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wdd->info = &sl28cpld_wdt_info; |
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wdd->ops = &sl28cpld_wdt_ops; |
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wdd->min_timeout = 1; |
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wdd->max_timeout = 255; |
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watchdog_set_drvdata(wdd, wdt); |
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watchdog_stop_on_reboot(wdd); |
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/* |
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* Read the status early, in case of an error, we haven't modified the |
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* hardware. |
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*/ |
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ret = regmap_read(wdt->regmap, wdt->offset + WDT_CTRL, &status); |
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if (ret) |
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return ret; |
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/* |
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* Initial timeout value, may be overwritten by device tree or module |
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* parmeter in watchdog_init_timeout(). |
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* |
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* Reading a zero here means that either the hardware has a default |
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* value of zero (which is very unlikely and definitely a hardware |
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* bug) or the bootloader set it to zero. In any case, we handle |
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* this case gracefully and set out own timeout. |
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*/ |
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ret = regmap_read(wdt->regmap, wdt->offset + WDT_TIMEOUT, &val); |
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if (ret) |
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return ret; |
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if (val) |
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wdd->timeout = val; |
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else |
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wdd->timeout = WDT_DEFAULT_TIMEOUT; |
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watchdog_init_timeout(wdd, timeout, &pdev->dev); |
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sl28cpld_wdt_set_timeout(wdd, wdd->timeout); |
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/* if the watchdog is locked, we set nowayout */ |
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if (status & WDT_CTRL_LOCK) |
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nowayout = true; |
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watchdog_set_nowayout(wdd, nowayout); |
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/* |
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* If watchdog is already running, keep it enabled, but make |
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* sure its mode is set correctly. |
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*/ |
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if (status & WDT_CTRL_EN) { |
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sl28cpld_wdt_start(wdd); |
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set_bit(WDOG_HW_RUNNING, &wdd->status); |
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} |
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ret = devm_watchdog_register_device(&pdev->dev, wdd); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "failed to register watchdog device\n"); |
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return ret; |
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} |
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dev_info(&pdev->dev, "initial timeout %d sec%s\n", |
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wdd->timeout, nowayout ? ", nowayout" : ""); |
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return 0; |
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} |
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static const struct of_device_id sl28cpld_wdt_of_match[] = { |
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{ .compatible = "kontron,sl28cpld-wdt" }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, sl28cpld_wdt_of_match); |
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static struct platform_driver sl28cpld_wdt_driver = { |
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.probe = sl28cpld_wdt_probe, |
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.driver = { |
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.name = "sl28cpld-wdt", |
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.of_match_table = sl28cpld_wdt_of_match, |
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}, |
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}; |
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module_platform_driver(sl28cpld_wdt_driver); |
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MODULE_DESCRIPTION("sl28cpld Watchdog Driver"); |
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MODULE_AUTHOR("Michael Walle <[email protected]>"); |
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MODULE_LICENSE("GPL");
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