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![Johannes Thumshirn](/assets/img/avatar_default.png)
This patch adds the driver for the watchdog devices found on MEN Mikro Elektronik A21 VMEbus CPU Carrier Boards. It has DT-support and uses the watchdog framework. Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
270 lines
5.8 KiB
C
270 lines
5.8 KiB
C
/*
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* Watchdog driver for the A21 VME CPU Boards
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*
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* Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/uaccess.h>
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#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#define NUM_GPIOS 6
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enum a21_wdt_gpios {
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GPIO_WD_ENAB,
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GPIO_WD_FAST,
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GPIO_WD_TRIG,
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GPIO_WD_RST0,
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GPIO_WD_RST1,
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GPIO_WD_RST2,
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};
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struct a21_wdt_drv {
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struct watchdog_device wdt;
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struct mutex lock;
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unsigned gpios[NUM_GPIOS];
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};
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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 unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
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{
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int reset = 0;
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reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
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reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
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reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
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return reset;
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}
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static int a21_wdt_start(struct watchdog_device *wdt)
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{
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struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
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mutex_lock(&drv->lock);
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gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1);
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mutex_unlock(&drv->lock);
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return 0;
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}
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static int a21_wdt_stop(struct watchdog_device *wdt)
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{
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struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
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mutex_lock(&drv->lock);
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gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
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mutex_unlock(&drv->lock);
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return 0;
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}
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static int a21_wdt_ping(struct watchdog_device *wdt)
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{
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struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
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mutex_lock(&drv->lock);
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gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0);
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ndelay(10);
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gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1);
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mutex_unlock(&drv->lock);
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return 0;
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}
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static int a21_wdt_set_timeout(struct watchdog_device *wdt,
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unsigned int timeout)
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{
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struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
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if (timeout != 1 && timeout != 30) {
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dev_err(wdt->dev, "Only 1 and 30 allowed as timeout\n");
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return -EINVAL;
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}
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if (timeout == 30 && wdt->timeout == 1) {
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dev_err(wdt->dev,
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"Transition from fast to slow mode not allowed\n");
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return -EINVAL;
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}
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mutex_lock(&drv->lock);
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if (timeout == 1)
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gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
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else
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gpio_set_value(drv->gpios[GPIO_WD_FAST], 0);
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wdt->timeout = timeout;
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mutex_unlock(&drv->lock);
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return 0;
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}
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static const struct watchdog_info a21_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "MEN A21 Watchdog",
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};
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static const struct watchdog_ops a21_wdt_ops = {
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.owner = THIS_MODULE,
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.start = a21_wdt_start,
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.stop = a21_wdt_stop,
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.ping = a21_wdt_ping,
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.set_timeout = a21_wdt_set_timeout,
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};
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static struct watchdog_device a21_wdt = {
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.info = &a21_wdt_info,
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.ops = &a21_wdt_ops,
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.min_timeout = 1,
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.max_timeout = 30,
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};
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static int a21_wdt_probe(struct platform_device *pdev)
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{
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struct device_node *node;
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struct a21_wdt_drv *drv;
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unsigned int reset = 0;
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int num_gpios;
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int ret;
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int i;
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drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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/* Fill GPIO pin array */
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node = pdev->dev.of_node;
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num_gpios = of_gpio_count(node);
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if (num_gpios != NUM_GPIOS) {
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dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
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num_gpios, NUM_GPIOS);
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return -ENODEV;
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}
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for (i = 0; i < num_gpios; i++) {
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int val;
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val = of_get_gpio(node, i);
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if (val < 0)
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return val;
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drv->gpios[i] = val;
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}
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/* Request the used GPIOs */
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for (i = 0; i < num_gpios; i++) {
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ret = devm_gpio_request(&pdev->dev, drv->gpios[i],
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"MEN A21 Watchdog");
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if (ret)
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return ret;
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if (i < GPIO_WD_RST0)
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ret = gpio_direction_output(drv->gpios[i],
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gpio_get_value(drv->gpios[i]));
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else /* GPIO_WD_RST[0..2] are inputs */
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ret = gpio_direction_input(drv->gpios[i]);
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if (ret)
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return ret;
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}
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mutex_init(&drv->lock);
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watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
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watchdog_set_nowayout(&a21_wdt, nowayout);
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watchdog_set_drvdata(&a21_wdt, drv);
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reset = a21_wdt_get_bootstatus(drv);
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if (reset == 2)
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a21_wdt.bootstatus |= WDIOF_EXTERN1;
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else if (reset == 4)
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a21_wdt.bootstatus |= WDIOF_CARDRESET;
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else if (reset == 5)
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a21_wdt.bootstatus |= WDIOF_POWERUNDER;
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else if (reset == 7)
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a21_wdt.bootstatus |= WDIOF_EXTERN2;
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ret = watchdog_register_device(&a21_wdt);
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if (ret) {
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dev_err(&pdev->dev, "Cannot register watchdog device\n");
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goto err_register_wd;
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}
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dev_set_drvdata(&pdev->dev, drv);
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dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
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return 0;
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err_register_wd:
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mutex_destroy(&drv->lock);
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return ret;
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}
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static int a21_wdt_remove(struct platform_device *pdev)
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{
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struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
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dev_warn(&pdev->dev,
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"Unregistering A21 watchdog driver, board may reboot\n");
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watchdog_unregister_device(&drv->wdt);
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mutex_destroy(&drv->lock);
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return 0;
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}
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static void a21_wdt_shutdown(struct platform_device *pdev)
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{
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struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
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gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
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}
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static const struct of_device_id a21_wdt_ids[] = {
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{ .compatible = "men,a021-wdt" },
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{ },
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};
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static struct platform_driver a21_wdt_driver = {
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.probe = a21_wdt_probe,
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.remove = a21_wdt_remove,
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.shutdown = a21_wdt_shutdown,
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.driver = {
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.name = "a21-watchdog",
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.of_match_table = a21_wdt_ids,
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},
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};
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module_platform_driver(a21_wdt_driver);
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MODULE_AUTHOR("MEN Mikro Elektronik");
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MODULE_DESCRIPTION("MEN A21 Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:a21-watchdog");
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