linux/drivers/watchdog/ep93xx_wdt.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

182 lines
4.5 KiB
C

/*
* Watchdog driver for Cirrus Logic EP93xx family of devices.
*
* Copyright (c) 2004 Ray Lehtiniemi
* Copyright (c) 2006 Tower Technologies
* Based on ep93xx driver, bits from alim7101_wdt.c
*
* Authors: Ray Lehtiniemi <rayl@mail.com>,
* Alessandro Zummo <a.zummo@towertech.it>
*
* Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
* Convert to a platform device and use the watchdog framework API
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* This watchdog fires after 250msec, which is a too short interval
* for us to rely on the user space daemon alone. So we ping the
* wdt each ~200msec and eventually stop doing it if the user space
* daemon dies.
*
* TODO:
*
* - Test last reset from watchdog status
* - Add a few missing ioctls
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/io.h>
#define WDT_VERSION "0.4"
/* default timeout (secs) */
#define WDT_TIMEOUT 30
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
static unsigned int timeout = WDT_TIMEOUT;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (1<=timeout<=3600, default="
__MODULE_STRING(WDT_TIMEOUT) ")");
static void __iomem *mmio_base;
static struct timer_list timer;
static unsigned long next_heartbeat;
#define EP93XX_WATCHDOG 0x00
#define EP93XX_WDSTATUS 0x04
/* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/
#define WDT_INTERVAL (HZ/5)
static void ep93xx_wdt_timer_ping(unsigned long data)
{
if (time_before(jiffies, next_heartbeat))
writel(0x5555, mmio_base + EP93XX_WATCHDOG);
/* Re-set the timer interval */
mod_timer(&timer, jiffies + WDT_INTERVAL);
}
static int ep93xx_wdt_start(struct watchdog_device *wdd)
{
next_heartbeat = jiffies + (timeout * HZ);
writel(0xaaaa, mmio_base + EP93XX_WATCHDOG);
mod_timer(&timer, jiffies + WDT_INTERVAL);
return 0;
}
static int ep93xx_wdt_stop(struct watchdog_device *wdd)
{
del_timer_sync(&timer);
writel(0xaa55, mmio_base + EP93XX_WATCHDOG);
return 0;
}
static int ep93xx_wdt_keepalive(struct watchdog_device *wdd)
{
/* user land ping */
next_heartbeat = jiffies + (timeout * HZ);
return 0;
}
static const struct watchdog_info ep93xx_wdt_ident = {
.options = WDIOF_CARDRESET |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.identity = "EP93xx Watchdog",
};
static struct watchdog_ops ep93xx_wdt_ops = {
.owner = THIS_MODULE,
.start = ep93xx_wdt_start,
.stop = ep93xx_wdt_stop,
.ping = ep93xx_wdt_keepalive,
};
static struct watchdog_device ep93xx_wdt_wdd = {
.info = &ep93xx_wdt_ident,
.ops = &ep93xx_wdt_ops,
};
static int ep93xx_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
unsigned long val;
int err;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENXIO;
if (!devm_request_mem_region(&pdev->dev, res->start,
resource_size(res), pdev->name))
return -EBUSY;
mmio_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!mmio_base)
return -ENXIO;
if (timeout < 1 || timeout > 3600) {
timeout = WDT_TIMEOUT;
dev_warn(&pdev->dev,
"timeout value must be 1<=x<=3600, using %d\n",
timeout);
}
val = readl(mmio_base + EP93XX_WATCHDOG);
ep93xx_wdt_wdd.bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
ep93xx_wdt_wdd.timeout = timeout;
watchdog_set_nowayout(&ep93xx_wdt_wdd, nowayout);
setup_timer(&timer, ep93xx_wdt_timer_ping, 1);
err = watchdog_register_device(&ep93xx_wdt_wdd);
if (err)
return err;
dev_info(&pdev->dev,
"EP93XX watchdog, driver version " WDT_VERSION "%s\n",
(val & 0x08) ? " (nCS1 disable detected)" : "");
return 0;
}
static int ep93xx_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&ep93xx_wdt_wdd);
return 0;
}
static struct platform_driver ep93xx_wdt_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "ep93xx-wdt",
},
.probe = ep93xx_wdt_probe,
.remove = ep93xx_wdt_remove,
};
module_platform_driver(ep93xx_wdt_driver);
MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
"Alessandro Zummo <a.zummo@towertech.it>,"
"H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_DESCRIPTION("EP93xx Watchdog");
MODULE_LICENSE("GPL");
MODULE_VERSION(WDT_VERSION);