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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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