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2f61b3a746
Proper machine resets via da9062/da9063 PMICs are very tricky as they
require special i2c atomic transfers when interrupts are not available
anymore. This is also a reason why both PMIC's restart handlers do not
use regmap but instead opt for i2c_smbus_write_byte_data() which does
i2c transfer in atomic manner. Under the hood, this function tries to
obtain i2c bus lock with call to i2c_adapter_trylock_bus() which will
return -EAGAIN (-11) if lock is not available.
Since commit 982bb70517 ("watchdog: reset last_hw_keepalive time at
start") occasional restart handler failures with "Failed to shutdown
(err = -11)" error messages were observed, indicating that some
process is holding the i2c bus lock. Investigation into the matter
uncovered that sometimes during reboot sequence watchdog ping is issued
late into poweroff/reboot phase which did not happen before mentioned
commit (usually the watchdog ping happened immediately as commit message
suggests). As of now, when watchdog ping usually happens late into
poweroff/reboot stage when interrupts are not available anymore, i2c bus
lock cannot be released anymore and pending restart handler in turn
fails.
Thus, to prevent such late watchdog pings from happening ahead of
pending machine restart and consequently locking up the i2c bus, check
for system_state in watchdog ping handler and consequently do not send
pings anymore in case system_state > SYSTEM_RUNNING.
Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Link: https://lore.kernel.org/r/20210708082128.2832904-1-primoz.fiser@norik.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
258 lines
6.6 KiB
C
258 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Watchdog driver for DA9063 PMICs.
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*
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* Copyright(c) 2012 Dialog Semiconductor Ltd.
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*
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* Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/uaccess.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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#include <linux/mfd/da9063/registers.h>
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#include <linux/mfd/da9063/core.h>
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#include <linux/regmap.h>
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/*
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* Watchdog selector to timeout in seconds.
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* 0: WDT disabled;
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* others: timeout = 2048 ms * 2^(TWDSCALE-1).
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*/
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static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
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#define DA9063_TWDSCALE_DISABLE 0
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#define DA9063_TWDSCALE_MIN 1
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#define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
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#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
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#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
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#define DA9063_WDG_TIMEOUT wdt_timeout[3]
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#define DA9063_RESET_PROTECTION_MS 256
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static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
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{
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unsigned int i;
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for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
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if (wdt_timeout[i] >= secs)
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return i;
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}
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return DA9063_TWDSCALE_MAX;
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}
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/*
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* Read the currently active timeout.
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* Zero means the watchdog is disabled.
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*/
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static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
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{
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unsigned int val;
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regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
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return wdt_timeout[val & DA9063_TWDSCALE_MASK];
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}
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static int da9063_wdt_disable_timer(struct da9063 *da9063)
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{
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return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
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DA9063_TWDSCALE_MASK,
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DA9063_TWDSCALE_DISABLE);
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}
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static int
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da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
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{
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unsigned int regval;
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int ret;
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/*
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* The watchdog triggers a reboot if a timeout value is already
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* programmed because the timeout value combines two functions
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* in one: indicating the counter limit and starting the watchdog.
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* The watchdog must be disabled to be able to change the timeout
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* value if the watchdog is already running. Then we can set the
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* new timeout value which enables the watchdog again.
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*/
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ret = da9063_wdt_disable_timer(da9063);
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if (ret)
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return ret;
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usleep_range(150, 300);
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regval = da9063_wdt_timeout_to_sel(timeout);
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return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
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DA9063_TWDSCALE_MASK, regval);
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}
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static int da9063_wdt_start(struct watchdog_device *wdd)
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{
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struct da9063 *da9063 = watchdog_get_drvdata(wdd);
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int ret;
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ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
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if (ret)
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dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
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ret);
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return ret;
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}
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static int da9063_wdt_stop(struct watchdog_device *wdd)
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{
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struct da9063 *da9063 = watchdog_get_drvdata(wdd);
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int ret;
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ret = da9063_wdt_disable_timer(da9063);
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if (ret)
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dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
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ret);
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return ret;
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}
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static int da9063_wdt_ping(struct watchdog_device *wdd)
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{
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struct da9063 *da9063 = watchdog_get_drvdata(wdd);
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int ret;
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/*
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* Prevent pings from occurring late in system poweroff/reboot sequence
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* and possibly locking out restart handler from accessing i2c bus.
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*/
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if (system_state > SYSTEM_RUNNING)
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return 0;
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ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
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DA9063_WATCHDOG);
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if (ret)
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dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
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ret);
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return ret;
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}
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static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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struct da9063 *da9063 = watchdog_get_drvdata(wdd);
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int ret = 0;
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/*
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* There are two cases when a set_timeout() will be called:
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* 1. The watchdog is off and someone wants to set the timeout for the
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* further use.
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* 2. The watchdog is already running and a new timeout value should be
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* set.
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*
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* The watchdog can't store a timeout value not equal zero without
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* enabling the watchdog, so the timeout must be buffered by the driver.
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*/
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if (watchdog_active(wdd))
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ret = da9063_wdt_update_timeout(da9063, timeout);
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if (ret)
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dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
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ret);
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else
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wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
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return ret;
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}
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static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
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void *data)
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{
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struct da9063 *da9063 = watchdog_get_drvdata(wdd);
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int ret;
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ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
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DA9063_SHUTDOWN);
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if (ret)
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dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
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ret);
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return ret;
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}
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static const struct watchdog_info da9063_watchdog_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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.identity = "DA9063 Watchdog",
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};
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static const struct watchdog_ops da9063_watchdog_ops = {
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.owner = THIS_MODULE,
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.start = da9063_wdt_start,
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.stop = da9063_wdt_stop,
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.ping = da9063_wdt_ping,
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.set_timeout = da9063_wdt_set_timeout,
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.restart = da9063_wdt_restart,
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};
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static int da9063_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct da9063 *da9063;
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struct watchdog_device *wdd;
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unsigned int timeout;
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if (!dev->parent)
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return -EINVAL;
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da9063 = dev_get_drvdata(dev->parent);
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if (!da9063)
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return -EINVAL;
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wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
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if (!wdd)
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return -ENOMEM;
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wdd->info = &da9063_watchdog_info;
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wdd->ops = &da9063_watchdog_ops;
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wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
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wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
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wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
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wdd->parent = dev;
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wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
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watchdog_set_restart_priority(wdd, 128);
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watchdog_set_drvdata(wdd, da9063);
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wdd->timeout = DA9063_WDG_TIMEOUT;
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/* Use pre-configured timeout if watchdog is already running. */
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timeout = da9063_wdt_read_timeout(da9063);
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if (timeout)
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wdd->timeout = timeout;
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/* Set timeout, maybe override it with DT value, scale it */
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watchdog_init_timeout(wdd, 0, dev);
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da9063_wdt_set_timeout(wdd, wdd->timeout);
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/* Update timeout if the watchdog is already running. */
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if (timeout) {
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da9063_wdt_update_timeout(da9063, wdd->timeout);
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set_bit(WDOG_HW_RUNNING, &wdd->status);
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}
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return devm_watchdog_register_device(dev, wdd);
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}
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static struct platform_driver da9063_wdt_driver = {
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.probe = da9063_wdt_probe,
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.driver = {
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.name = DA9063_DRVNAME_WATCHDOG,
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},
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};
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module_platform_driver(da9063_wdt_driver);
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MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
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MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
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