watchdog: New watchdog driver for MEN A21 watchdogs

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>
This commit is contained in:
Johannes Thumshirn 2013-06-18 17:19:45 +02:00 committed by Wim Van Sebroeck
parent 6910ceb5ca
commit 26c57ef1ea
5 changed files with 314 additions and 0 deletions

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@ -0,0 +1,25 @@
Bindings for MEN A21 Watchdog device connected to GPIO lines
Required properties:
- compatible: "men,a021-wdt"
- gpios: Specifies the pins that control the Watchdog, order:
1: Watchdog enable
2: Watchdog fast-mode
3: Watchdog trigger
4: Watchdog reset cause bit 0
5: Watchdog reset cause bit 1
6: Watchdog reset cause bit 2
Optional properties:
- None
Example:
watchdog {
compatible ="men,a021-wdt";
gpios = <&gpio3 9 1 /* WD_EN */
&gpio3 10 1 /* WD_FAST */
&gpio3 11 1 /* WD_TRIG */
&gpio3 6 1 /* RST_CAUSE[0] */
&gpio3 7 1 /* RST_CAUSE[1] */
&gpio3 8 1>; /* RST_CAUSE[2] */
};

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@ -5394,6 +5394,12 @@ F: drivers/mtd/
F: include/linux/mtd/
F: include/uapi/mtd/
MEN A21 WATCHDOG DRIVER
M: Johannes Thumshirn <johannes.thumshirn@men.de>
L: linux-watchdog@vger.kernel.org
S: Supported
F: drivers/watchdog/mena21_wdt.c
METAG ARCHITECTURE
M: James Hogan <james.hogan@imgtec.com>
S: Supported

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@ -1185,6 +1185,18 @@ config BOOKE_WDT_DEFAULT_TIMEOUT
The value can be overridden by the wdt_period command-line parameter.
config MEN_A21_WDT
tristate "MEN A21 VME CPU Carrier Board Watchdog Timer"
select WATCHDOG_CORE
depends on GPIOLIB
help
Watchdog driver for MEN A21 VMEbus CPU Carrier Boards.
The driver can also be built as a module. If so, the module will be
called mena21_wdt.
If unsure select N here.
# PPC64 Architecture
config WATCHDOG_RTAS

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@ -144,6 +144,7 @@ obj-$(CONFIG_8xxx_WDT) += mpc8xxx_wdt.o
obj-$(CONFIG_MV64X60_WDT) += mv64x60_wdt.o
obj-$(CONFIG_PIKA_WDT) += pika_wdt.o
obj-$(CONFIG_BOOKE_WDT) += booke_wdt.o
obj-$(CONFIG_MEN_A21_WDT) += mena21_wdt.o
# PPC64 Architecture
obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o

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@ -0,0 +1,270 @@
/*
* 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->dev, "Only 1 and 30 allowed as timeout\n");
return -EINVAL;
}
if (timeout == 30 && wdt->timeout == 1) {
dev_err(wdt->dev,
"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);
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;
ret = watchdog_register_device(&a21_wdt);
if (ret) {
dev_err(&pdev->dev, "Cannot register watchdog device\n");
goto err_register_wd;
}
dev_set_drvdata(&pdev->dev, drv);
dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
return 0;
err_register_wd:
mutex_destroy(&drv->lock);
return ret;
}
static int a21_wdt_remove(struct platform_device *pdev)
{
struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
dev_warn(&pdev->dev,
"Unregistering A21 watchdog driver, board may reboot\n");
watchdog_unregister_device(&drv->wdt);
mutex_destroy(&drv->lock);
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" },
{ },
};
static struct platform_driver a21_wdt_driver = {
.probe = a21_wdt_probe,
.remove = a21_wdt_remove,
.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");