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linux/drivers/watchdog/jz4740_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

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/*
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 Watchdog driver
*
* 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; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <asm/mach-jz4740/timer.h>
#define JZ_REG_WDT_TIMER_DATA 0x0
#define JZ_REG_WDT_COUNTER_ENABLE 0x4
#define JZ_REG_WDT_TIMER_COUNTER 0x8
#define JZ_REG_WDT_TIMER_CONTROL 0xC
#define JZ_WDT_CLOCK_PCLK 0x1
#define JZ_WDT_CLOCK_RTC 0x2
#define JZ_WDT_CLOCK_EXT 0x4
#define JZ_WDT_CLOCK_DIV_SHIFT 3
#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
#define DEFAULT_HEARTBEAT 5
#define MAX_HEARTBEAT 2048
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 heartbeat = DEFAULT_HEARTBEAT;
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
struct jz4740_wdt_drvdata {
struct watchdog_device wdt;
void __iomem *base;
struct clk *rtc_clk;
};
static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
return 0;
}
static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
unsigned int rtc_clk_rate;
unsigned int timeout_value;
unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
timeout_value = rtc_clk_rate * new_timeout;
while (timeout_value > 0xffff) {
if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
/* Requested timeout too high;
* use highest possible value. */
timeout_value = 0xffff;
break;
}
timeout_value >>= 2;
clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
}
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
writew(clock_div | JZ_WDT_CLOCK_RTC,
drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
wdt_dev->timeout = new_timeout;
return 0;
}
static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
{
jz4740_timer_enable_watchdog();
jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
return 0;
}
static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
jz4740_timer_disable_watchdog();
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
return 0;
}
static const struct watchdog_info jz4740_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "jz4740 Watchdog",
};
static const struct watchdog_ops jz4740_wdt_ops = {
.owner = THIS_MODULE,
.start = jz4740_wdt_start,
.stop = jz4740_wdt_stop,
.ping = jz4740_wdt_ping,
.set_timeout = jz4740_wdt_set_timeout,
};
static int jz4740_wdt_probe(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata;
struct watchdog_device *jz4740_wdt;
struct resource *res;
int ret;
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
GFP_KERNEL);
if (!drvdata) {
dev_err(&pdev->dev, "Unable to alloacate watchdog device\n");
return -ENOMEM;
}
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
jz4740_wdt = &drvdata->wdt;
jz4740_wdt->info = &jz4740_wdt_info;
jz4740_wdt->ops = &jz4740_wdt_ops;
jz4740_wdt->timeout = heartbeat;
jz4740_wdt->min_timeout = 1;
jz4740_wdt->max_timeout = MAX_HEARTBEAT;
watchdog_set_nowayout(jz4740_wdt, nowayout);
watchdog_set_drvdata(jz4740_wdt, drvdata);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
drvdata->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(drvdata->base)) {
ret = PTR_ERR(drvdata->base);
goto err_out;
}
drvdata->rtc_clk = clk_get(&pdev->dev, "rtc");
if (IS_ERR(drvdata->rtc_clk)) {
dev_err(&pdev->dev, "cannot find RTC clock\n");
ret = PTR_ERR(drvdata->rtc_clk);
goto err_out;
}
ret = watchdog_register_device(&drvdata->wdt);
if (ret < 0)
goto err_disable_clk;
platform_set_drvdata(pdev, drvdata);
return 0;
err_disable_clk:
clk_put(drvdata->rtc_clk);
err_out:
return ret;
}
static int jz4740_wdt_remove(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
jz4740_wdt_stop(&drvdata->wdt);
watchdog_unregister_device(&drvdata->wdt);
clk_put(drvdata->rtc_clk);
return 0;
}
static struct platform_driver jz4740_wdt_driver = {
.probe = jz4740_wdt_probe,
.remove = jz4740_wdt_remove,
.driver = {
.name = "jz4740-wdt",
.owner = THIS_MODULE,
},
};
module_platform_driver(jz4740_wdt_driver);
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("jz4740 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:jz4740-wdt");
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