linux/drivers/watchdog/atlas7_wdt.c
Guenter Roeck f332ce5d88 watchdog: atlas7_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

- Drop assignments to otherwise unused variables
- Drop unnecessary braces around conditional return statements
- Drop empty remove function
- Use devm_add_action_or_reset() for calls to clk_disable_unprepare
- Replace 'of_clk_get(np, 0)' with 'devm_clk_get(dev, NULL)'
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
- Replace shutdown function with call to watchdog_stop_on_reboot()

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:15 +02:00

223 lines
5.4 KiB
C

/*
* Watchdog driver for CSR Atlas7
*
* Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define ATLAS7_TIMER_WDT_INDEX 5
#define ATLAS7_WDT_DEFAULT_TIMEOUT 20
#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_MATCH (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT (0x48 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_EN (BIT(0) | BIT(1))
#define ATLAS7_WDT_EN 0x64
static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(timeout, uint, 0);
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct atlas7_wdog {
struct device *dev;
void __iomem *base;
unsigned long tick_rate;
struct clk *clk;
};
static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
u32 counter, match, delta;
counter = readl(wdt->base + ATLAS7_WDT_CNT);
match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);
delta = match - counter;
return delta / wdt->tick_rate;
}
static int atlas7_wdt_ping(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
u32 counter, match, delta;
counter = readl(wdt->base + ATLAS7_WDT_CNT);
delta = wdd->timeout * wdt->tick_rate;
match = counter + delta;
writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);
return 0;
}
static int atlas7_wdt_enable(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
atlas7_wdt_ping(wdd);
writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,
wdt->base + ATLAS7_WDT_CNT_CTRL);
writel(1, wdt->base + ATLAS7_WDT_EN);
return 0;
}
static int atlas7_wdt_disable(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
writel(0, wdt->base + ATLAS7_WDT_EN);
writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,
wdt->base + ATLAS7_WDT_CNT_CTRL);
return 0;
}
static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
{
wdd->timeout = to;
return 0;
}
#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
static const struct watchdog_info atlas7_wdt_ident = {
.options = OPTIONS,
.firmware_version = 0,
.identity = "atlas7 Watchdog",
};
static const struct watchdog_ops atlas7_wdt_ops = {
.owner = THIS_MODULE,
.start = atlas7_wdt_enable,
.stop = atlas7_wdt_disable,
.get_timeleft = atlas7_wdt_gettimeleft,
.ping = atlas7_wdt_ping,
.set_timeout = atlas7_wdt_settimeout,
};
static struct watchdog_device atlas7_wdd = {
.info = &atlas7_wdt_ident,
.ops = &atlas7_wdt_ops,
.timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
};
static const struct of_device_id atlas7_wdt_ids[] = {
{ .compatible = "sirf,atlas7-tick"},
{}
};
static void atlas7_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int atlas7_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct atlas7_wdog *wdt;
struct clk *clk;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "clk enable failed\n");
return ret;
}
ret = devm_add_action_or_reset(dev, atlas7_clk_disable_unprepare, clk);
if (ret)
return ret;
/* disable watchdog hardware */
writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL);
wdt->tick_rate = clk_get_rate(clk);
if (!wdt->tick_rate)
return -EINVAL;
wdt->clk = clk;
atlas7_wdd.min_timeout = 1;
atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;
watchdog_init_timeout(&atlas7_wdd, 0, dev);
watchdog_set_nowayout(&atlas7_wdd, nowayout);
watchdog_set_drvdata(&atlas7_wdd, wdt);
platform_set_drvdata(pdev, &atlas7_wdd);
watchdog_stop_on_reboot(&atlas7_wdd);
watchdog_stop_on_unregister(&atlas7_wdd);
return devm_watchdog_register_device(dev, &atlas7_wdd);
}
static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
{
/*
* NOTE:timer controller registers settings are saved
* and restored back by the timer-atlas7.c
*/
return 0;
}
static int __maybe_unused atlas7_wdt_resume(struct device *dev)
{
struct watchdog_device *wdd = dev_get_drvdata(dev);
/*
* NOTE: Since timer controller registers settings are saved
* and restored back by the timer-atlas7.c, so we need not
* update WD settings except refreshing timeout.
*/
atlas7_wdt_ping(wdd);
return 0;
}
static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
atlas7_wdt_suspend, atlas7_wdt_resume);
MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);
static struct platform_driver atlas7_wdt_driver = {
.driver = {
.name = "atlas7-wdt",
.pm = &atlas7_wdt_pm_ops,
.of_match_table = atlas7_wdt_ids,
},
.probe = atlas7_wdt_probe,
};
module_platform_driver(atlas7_wdt_driver);
MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:atlas7-wdt");