linux/drivers/watchdog/mena21_wdt.c
Guenter Roeck cb5c14ea57 watchdog: mena21_wdt: Convert to use device managed functions and other improvements
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts used
to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Replace 'goto l; ... l: return e;' with 'return e;'
- Drop assignments to otherwise unused variables
- Drop remove function
- Drop unnecessary mutex_destroy() on allocated data
- Use devm_watchdog_register_driver() to register watchdog device

Acked-by: Johannes Thumshirn <morbidrsa@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00

254 lines
5.5 KiB
C

/*
* Watchdog driver for the A21 VME CPU Boards
*
* Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation
*/
#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.h>
#include <linux/of_gpio.h>
#include <linux/delay.h>
#include <linux/bitops.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 mutex lock;
unsigned 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 |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
reset |= gpio_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);
mutex_lock(&drv->lock);
gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1);
mutex_unlock(&drv->lock);
return 0;
}
static int a21_wdt_stop(struct watchdog_device *wdt)
{
struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
mutex_lock(&drv->lock);
gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
mutex_unlock(&drv->lock);
return 0;
}
static int a21_wdt_ping(struct watchdog_device *wdt)
{
struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
mutex_lock(&drv->lock);
gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0);
ndelay(10);
gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1);
mutex_unlock(&drv->lock);
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;
}
mutex_lock(&drv->lock);
if (timeout == 1)
gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
else
gpio_set_value(drv->gpios[GPIO_WD_FAST], 0);
wdt->timeout = timeout;
mutex_unlock(&drv->lock);
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_node *node;
struct a21_wdt_drv *drv;
unsigned int reset = 0;
int num_gpios;
int ret;
int i;
drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
if (!drv)
return -ENOMEM;
/* Fill GPIO pin array */
node = pdev->dev.of_node;
num_gpios = of_gpio_count(node);
if (num_gpios != NUM_GPIOS) {
dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
num_gpios, NUM_GPIOS);
return -ENODEV;
}
for (i = 0; i < num_gpios; i++) {
int val;
val = of_get_gpio(node, i);
if (val < 0)
return val;
drv->gpios[i] = val;
}
/* Request the used GPIOs */
for (i = 0; i < num_gpios; i++) {
ret = devm_gpio_request(&pdev->dev, drv->gpios[i],
"MEN A21 Watchdog");
if (ret)
return ret;
if (i < GPIO_WD_RST0)
ret = gpio_direction_output(drv->gpios[i],
gpio_get_value(drv->gpios[i]));
else /* GPIO_WD_RST[0..2] are inputs */
ret = gpio_direction_input(drv->gpios[i]);
if (ret)
return ret;
}
mutex_init(&drv->lock);
watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
watchdog_set_nowayout(&a21_wdt, nowayout);
watchdog_set_drvdata(&a21_wdt, drv);
a21_wdt.parent = &pdev->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(&pdev->dev, drv);
ret = devm_watchdog_register_device(&pdev->dev, &a21_wdt);
if (ret) {
dev_err(&pdev->dev, "Cannot register watchdog device\n");
return ret;
}
dev_info(&pdev->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);
gpio_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");