linux/drivers/watchdog/max63xx_wdt.c
Guenter Roeck 80cb6bddeb watchdog: max63xx_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 empty remove function
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:22 +02:00

287 lines
6.8 KiB
C

/*
* drivers/char/watchdog/max63xx_wdt.c
*
* Driver for max63{69,70,71,72,73,74} watchdog timers
*
* Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
*
* 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 driver assumes the watchdog pins are memory mapped (as it is
* the case for the Arcom Zeus). Should it be connected over GPIOs or
* another interface, some abstraction will have to be introduced.
*/
#include <linux/err.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mod_devicetable.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/slab.h>
#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT 60
static unsigned int heartbeat = DEFAULT_HEARTBEAT;
static bool nowayout = WATCHDOG_NOWAYOUT;
/*
* Memory mapping: a single byte, 3 first lower bits to select bit 3
* to ping the watchdog.
*/
#define MAX6369_WDSET (7 << 0)
#define MAX6369_WDI (1 << 3)
#define MAX6369_WDSET_DISABLED 3
static int nodelay;
struct max63xx_wdt {
struct watchdog_device wdd;
const struct max63xx_timeout *timeout;
/* memory mapping */
void __iomem *base;
spinlock_t lock;
/* WDI and WSET bits write access routines */
void (*ping)(struct max63xx_wdt *wdt);
void (*set)(struct max63xx_wdt *wdt, u8 set);
};
/*
* The timeout values used are actually the absolute minimum the chip
* offers. Typical values on my board are slightly over twice as long
* (10s setting ends up with a 25s timeout), and can be up to 3 times
* the nominal setting (according to the datasheet). So please take
* these values with a grain of salt. Same goes for the initial delay
* "feature". Only max6373/74 have a few settings without this initial
* delay (selected with the "nodelay" parameter).
*
* I also decided to remove from the tables any timeout smaller than a
* second, as it looked completly overkill...
*/
/* Timeouts in second */
struct max63xx_timeout {
const u8 wdset;
const u8 tdelay;
const u8 twd;
};
static const struct max63xx_timeout max6369_table[] = {
{ 5, 1, 1 },
{ 6, 10, 10 },
{ 7, 60, 60 },
{ },
};
static const struct max63xx_timeout max6371_table[] = {
{ 6, 60, 3 },
{ 7, 60, 60 },
{ },
};
static const struct max63xx_timeout max6373_table[] = {
{ 2, 60, 1 },
{ 5, 0, 1 },
{ 1, 3, 3 },
{ 7, 60, 10 },
{ 6, 0, 10 },
{ },
};
static struct max63xx_timeout *
max63xx_select_timeout(struct max63xx_timeout *table, int value)
{
while (table->twd) {
if (value <= table->twd) {
if (nodelay && table->tdelay == 0)
return table;
if (!nodelay)
return table;
}
table++;
}
return NULL;
}
static int max63xx_wdt_ping(struct watchdog_device *wdd)
{
struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
wdt->ping(wdt);
return 0;
}
static int max63xx_wdt_start(struct watchdog_device *wdd)
{
struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
wdt->set(wdt, wdt->timeout->wdset);
/* check for a edge triggered startup */
if (wdt->timeout->tdelay == 0)
wdt->ping(wdt);
return 0;
}
static int max63xx_wdt_stop(struct watchdog_device *wdd)
{
struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
wdt->set(wdt, MAX6369_WDSET_DISABLED);
return 0;
}
static const struct watchdog_ops max63xx_wdt_ops = {
.owner = THIS_MODULE,
.start = max63xx_wdt_start,
.stop = max63xx_wdt_stop,
.ping = max63xx_wdt_ping,
};
static const struct watchdog_info max63xx_wdt_info = {
.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "max63xx Watchdog",
};
static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
{
u8 val;
spin_lock(&wdt->lock);
val = __raw_readb(wdt->base);
__raw_writeb(val | MAX6369_WDI, wdt->base);
__raw_writeb(val & ~MAX6369_WDI, wdt->base);
spin_unlock(&wdt->lock);
}
static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
{
u8 val;
spin_lock(&wdt->lock);
val = __raw_readb(wdt->base);
val &= ~MAX6369_WDSET;
val |= set & MAX6369_WDSET;
__raw_writeb(val, wdt->base);
spin_unlock(&wdt->lock);
}
static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt)
{
wdt->base = devm_platform_ioremap_resource(p, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
spin_lock_init(&wdt->lock);
wdt->ping = max63xx_mmap_ping;
wdt->set = max63xx_mmap_set;
return 0;
}
static int max63xx_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct max63xx_wdt *wdt;
struct max63xx_timeout *table;
int err;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
wdt->timeout = max63xx_select_timeout(table, heartbeat);
if (!wdt->timeout) {
dev_err(dev, "unable to satisfy %ds heartbeat request\n",
heartbeat);
return -EINVAL;
}
err = max63xx_mmap_init(pdev, wdt);
if (err)
return err;
platform_set_drvdata(pdev, &wdt->wdd);
watchdog_set_drvdata(&wdt->wdd, wdt);
wdt->wdd.parent = dev;
wdt->wdd.timeout = wdt->timeout->twd;
wdt->wdd.info = &max63xx_wdt_info;
wdt->wdd.ops = &max63xx_wdt_ops;
watchdog_set_nowayout(&wdt->wdd, nowayout);
err = devm_watchdog_register_device(dev, &wdt->wdd);
if (err)
return err;
dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
wdt->timeout->twd, wdt->timeout->tdelay);
return 0;
}
static const struct platform_device_id max63xx_id_table[] = {
{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
{ },
};
MODULE_DEVICE_TABLE(platform, max63xx_id_table);
static struct platform_driver max63xx_wdt_driver = {
.probe = max63xx_wdt_probe,
.id_table = max63xx_id_table,
.driver = {
.name = "max63xx_wdt",
},
};
module_platform_driver(max63xx_wdt_driver);
MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
MODULE_DESCRIPTION("max63xx Watchdog Driver");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
module_param(nodelay, int, 0);
MODULE_PARM_DESC(nodelay,
"Force selection of a timeout setting without initial delay "
"(max6373/74 only, default=0)");
MODULE_LICENSE("GPL v2");