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linux/drivers/watchdog/da9062_wdt.c
Stefan Riedmueller a0948ddba6 watchdog: da9062: No need to ping manually before setting timeout 
There is actually no need to ping the watchdog before disabling it
during timeout change. Disabling the watchdog already takes care of
resetting the counter.

This fixes an issue during boot when the userspace watchdog handler takes
over and the watchdog is already running. Opening the watchdog in this case
leads to the first ping and directly after that without the required
heartbeat delay a second ping issued by the set_timeout call. Due to the
missing delay this resulted in a reset.

Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Link: https://lore.kernel.org/r/20200403130728.39260-3-s.riedmueller@phytec.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-25 08:55:44 +02:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog device driver for DA9062 and DA9061 PMICs
* Copyright (C) 2015 Dialog Semiconductor Ltd.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/mfd/da9062/registers.h>
#include <linux/mfd/da9062/core.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/of.h>
static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
#define DA9062_TWDSCALE_DISABLE 0
#define DA9062_TWDSCALE_MIN 1
#define DA9062_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
#define DA9062_WDT_MIN_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MIN]
#define DA9062_WDT_MAX_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX]
#define DA9062_WDG_DEFAULT_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX-1]
#define DA9062_RESET_PROTECTION_MS 300
struct da9062_watchdog {
struct da9062 *hw;
struct watchdog_device wdtdev;
bool use_sw_pm;
};
static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
{
unsigned int val;
regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
}
static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
{
unsigned int i;
for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
if (wdt_timeout[i] >= secs)
return i;
}
return DA9062_TWDSCALE_MAX;
}
static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
{
return regmap_update_bits(wdt->hw->regmap, DA9062AA_CONTROL_F,
DA9062AA_WATCHDOG_MASK,
DA9062AA_WATCHDOG_MASK);
}
static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
unsigned int regval)
{
struct da9062 *chip = wdt->hw;
regmap_update_bits(chip->regmap,
DA9062AA_CONTROL_D,
DA9062AA_TWDSCALE_MASK,
DA9062_TWDSCALE_DISABLE);
usleep_range(150, 300);
return regmap_update_bits(chip->regmap,
DA9062AA_CONTROL_D,
DA9062AA_TWDSCALE_MASK,
regval);
}
static int da9062_wdt_start(struct watchdog_device *wdd)
{
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
unsigned int selector;
int ret;
selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
ret = da9062_wdt_update_timeout_register(wdt, selector);
if (ret)
dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
ret);
return ret;
}
static int da9062_wdt_stop(struct watchdog_device *wdd)
{
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_update_bits(wdt->hw->regmap,
DA9062AA_CONTROL_D,
DA9062AA_TWDSCALE_MASK,
DA9062_TWDSCALE_DISABLE);
if (ret)
dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
ret);
return ret;
}
static int da9062_wdt_ping(struct watchdog_device *wdd)
{
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = da9062_reset_watchdog_timer(wdt);
if (ret)
dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
ret);
return ret;
}
static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
unsigned int selector;
int ret;
selector = da9062_wdt_timeout_to_sel(timeout);
ret = da9062_wdt_update_timeout_register(wdt, selector);
if (ret)
dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
ret);
else
wdd->timeout = wdt_timeout[selector];
return ret;
}
static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
struct i2c_client *client = to_i2c_client(wdt->hw->dev);
int ret;
/* Don't use regmap because it is not atomic safe */
ret = i2c_smbus_write_byte_data(client, DA9062AA_CONTROL_F,
DA9062AA_SHUTDOWN_MASK);
if (ret < 0)
dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
ret);
/* wait for reset to assert... */
mdelay(500);
return ret;
}
static const struct watchdog_info da9062_watchdog_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "DA9062 WDT",
};
static const struct watchdog_ops da9062_watchdog_ops = {
.owner = THIS_MODULE,
.start = da9062_wdt_start,
.stop = da9062_wdt_stop,
.ping = da9062_wdt_ping,
.set_timeout = da9062_wdt_set_timeout,
.restart = da9062_wdt_restart,
};
static const struct of_device_id da9062_compatible_id_table[] = {
{ .compatible = "dlg,da9062-watchdog", },
{ },
};
MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
static int da9062_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
unsigned int timeout;
struct da9062 *chip;
struct da9062_watchdog *wdt;
chip = dev_get_drvdata(dev->parent);
if (!chip)
return -EINVAL;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
wdt->hw = chip;
wdt->wdtdev.info = &da9062_watchdog_info;
wdt->wdtdev.ops = &da9062_watchdog_ops;
wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
wdt->wdtdev.parent = dev;
watchdog_set_restart_priority(&wdt->wdtdev, 128);
watchdog_set_drvdata(&wdt->wdtdev, wdt);
dev_set_drvdata(dev, &wdt->wdtdev);
timeout = da9062_wdt_read_timeout(wdt);
if (timeout)
wdt->wdtdev.timeout = timeout;
/* Set timeout from DT value if available */
watchdog_init_timeout(&wdt->wdtdev, 0, dev);
if (timeout) {
da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
}
return devm_watchdog_register_device(dev, &wdt->wdtdev);
}
static int __maybe_unused da9062_wdt_suspend(struct device *dev)
{
struct watchdog_device *wdd = dev_get_drvdata(dev);
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
if (!wdt->use_sw_pm)
return 0;
if (watchdog_active(wdd))
return da9062_wdt_stop(wdd);
return 0;
}
static int __maybe_unused da9062_wdt_resume(struct device *dev)
{
struct watchdog_device *wdd = dev_get_drvdata(dev);
struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
if (!wdt->use_sw_pm)
return 0;
if (watchdog_active(wdd))
return da9062_wdt_start(wdd);
return 0;
}
static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
da9062_wdt_suspend, da9062_wdt_resume);
static struct platform_driver da9062_wdt_driver = {
.probe = da9062_wdt_probe,
.driver = {
.name = "da9062-watchdog",
.pm = &da9062_wdt_pm_ops,
.of_match_table = da9062_compatible_id_table,
},
};
module_platform_driver(da9062_wdt_driver);
MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9062-watchdog");
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