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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Watchdog driver for the A21 VME CPU Boards
- *
- * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
- *
- */
- #include <linux/module.h>
- #include <linux/moduleparam.h>
- #include <linux/types.h>
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/platform_device.h>
- #include <linux/watchdog.h>
- #include <linux/uaccess.h>
- #include <linux/gpio/consumer.h>
- #include <linux/delay.h>
- #include <linux/bitops.h>
- #include <linux/of.h>
- #define NUM_GPIOS 6
- enum a21_wdt_gpios {
- GPIO_WD_ENAB,
- GPIO_WD_FAST,
- GPIO_WD_TRIG,
- GPIO_WD_RST0,
- GPIO_WD_RST1,
- GPIO_WD_RST2,
- };
- struct a21_wdt_drv {
- struct watchdog_device wdt;
- struct gpio_desc *gpios[NUM_GPIOS];
- };
- static bool nowayout = WATCHDOG_NOWAYOUT;
- module_param(nowayout, bool, 0);
- MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
- __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
- static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
- {
- int reset = 0;
- reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
- reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
- reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
- return reset;
- }
- static int a21_wdt_start(struct watchdog_device *wdt)
- {
- struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
- gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);
- return 0;
- }
- static int a21_wdt_stop(struct watchdog_device *wdt)
- {
- struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
- gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
- return 0;
- }
- static int a21_wdt_ping(struct watchdog_device *wdt)
- {
- struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
- gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);
- ndelay(10);
- gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);
- return 0;
- }
- static int a21_wdt_set_timeout(struct watchdog_device *wdt,
- unsigned int timeout)
- {
- struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
- if (timeout != 1 && timeout != 30) {
- dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
- return -EINVAL;
- }
- if (timeout == 30 && wdt->timeout == 1) {
- dev_err(wdt->parent,
- "Transition from fast to slow mode not allowed\n");
- return -EINVAL;
- }
- if (timeout == 1)
- gpiod_set_value(drv->gpios[GPIO_WD_FAST], 1);
- else
- gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);
- wdt->timeout = timeout;
- return 0;
- }
- static const struct watchdog_info a21_wdt_info = {
- .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
- .identity = "MEN A21 Watchdog",
- };
- static const struct watchdog_ops a21_wdt_ops = {
- .owner = THIS_MODULE,
- .start = a21_wdt_start,
- .stop = a21_wdt_stop,
- .ping = a21_wdt_ping,
- .set_timeout = a21_wdt_set_timeout,
- };
- static struct watchdog_device a21_wdt = {
- .info = &a21_wdt_info,
- .ops = &a21_wdt_ops,
- .min_timeout = 1,
- .max_timeout = 30,
- };
- static int a21_wdt_probe(struct platform_device *pdev)
- {
- struct device *dev = &pdev->dev;
- struct a21_wdt_drv *drv;
- unsigned int reset = 0;
- int num_gpios;
- int ret;
- int i;
- drv = devm_kzalloc(dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
- if (!drv)
- return -ENOMEM;
- num_gpios = gpiod_count(dev, NULL);
- if (num_gpios != NUM_GPIOS) {
- dev_err(dev, "gpios DT property wrong, got %d want %d",
- num_gpios, NUM_GPIOS);
- return -ENODEV;
- }
- /* Request the used GPIOs */
- for (i = 0; i < num_gpios; i++) {
- enum gpiod_flags gflags;
- if (i < GPIO_WD_RST0)
- gflags = GPIOD_ASIS;
- else
- gflags = GPIOD_IN;
- drv->gpios[i] = devm_gpiod_get_index(dev, NULL, i, gflags);
- if (IS_ERR(drv->gpios[i]))
- return PTR_ERR(drv->gpios[i]);
- gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");
- /*
- * Retrieve the initial value from the GPIOs that should be
- * output, then set up the line as output with that value.
- */
- if (i < GPIO_WD_RST0) {
- int val;
- val = gpiod_get_value(drv->gpios[i]);
- gpiod_direction_output(drv->gpios[i], val);
- }
- }
- watchdog_init_timeout(&a21_wdt, 30, dev);
- watchdog_set_nowayout(&a21_wdt, nowayout);
- watchdog_set_drvdata(&a21_wdt, drv);
- a21_wdt.parent = dev;
- reset = a21_wdt_get_bootstatus(drv);
- if (reset == 2)
- a21_wdt.bootstatus |= WDIOF_EXTERN1;
- else if (reset == 4)
- a21_wdt.bootstatus |= WDIOF_CARDRESET;
- else if (reset == 5)
- a21_wdt.bootstatus |= WDIOF_POWERUNDER;
- else if (reset == 7)
- a21_wdt.bootstatus |= WDIOF_EXTERN2;
- drv->wdt = a21_wdt;
- dev_set_drvdata(dev, drv);
- ret = devm_watchdog_register_device(dev, &a21_wdt);
- if (ret)
- return ret;
- dev_info(dev, "MEN A21 watchdog timer driver enabled\n");
- return 0;
- }
- static void a21_wdt_shutdown(struct platform_device *pdev)
- {
- struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
- gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
- }
- static const struct of_device_id a21_wdt_ids[] = {
- { .compatible = "men,a021-wdt" },
- { },
- };
- MODULE_DEVICE_TABLE(of, a21_wdt_ids);
- static struct platform_driver a21_wdt_driver = {
- .probe = a21_wdt_probe,
- .shutdown = a21_wdt_shutdown,
- .driver = {
- .name = "a21-watchdog",
- .of_match_table = a21_wdt_ids,
- },
- };
- module_platform_driver(a21_wdt_driver);
- MODULE_AUTHOR("MEN Mikro Elektronik");
- MODULE_DESCRIPTION("MEN A21 Watchdog");
- MODULE_LICENSE("GPL");
- MODULE_ALIAS("platform:a21-watchdog");
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