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![Primoz Fiser](/assets/img/avatar_default.png)
Machine resets via da9062/da9063 PMICs are challenging since one needs to use special i2c atomic transfers due to the fact interrupts are disabled in such late system stages. This is the reason both PMICs don't use regmap and have instead opted for i2c_smbus_write_byte_data() in restart handlers. However extensive testing revealed that even using atomic safe function is not enough and occasional resets fail with error message "Failed to shutdown (err = -11)". This is due to the fact that function i2c_smbus_write_byte_data() in turn calls __i2c_lock_bus_helper() which might fail with -EAGAIN when bus lock is already taken and cannot be released anymore. Thus replace i2c_smbus_write_byte_data() with unlocked flavor of i2c_smbus_xfer() function to avoid above dead-lock scenario. At this system stage we don't care about proper locking anymore and only want proper machine reset to be carried out. Signed-off-by: Primoz Fiser <primoz.fiser@norik.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20221216083645.2574077-1-primoz.fiser@norik.com [groeck: Fixed continuation line alignment] Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
308 lines
7.8 KiB
C
308 lines
7.8 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/i2c.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/property.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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static bool use_sw_pm;
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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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struct i2c_client *client = to_i2c_client(da9063->dev);
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union i2c_smbus_data msg;
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int ret;
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/*
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* Don't use regmap because it is not atomic safe. Additionally, use
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* unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
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* might previously be locked by some process unable to release the
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* lock due to interrupts already being disabled at this late stage.
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*/
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msg.byte = DA9063_SHUTDOWN;
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ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
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I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F,
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I2C_SMBUS_BYTE_DATA, &msg);
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if (ret < 0)
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dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
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ret);
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/* wait for reset to assert... */
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mdelay(500);
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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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use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
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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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dev_set_drvdata(dev, wdd);
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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 int __maybe_unused da9063_wdt_suspend(struct device *dev)
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{
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struct watchdog_device *wdd = dev_get_drvdata(dev);
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if (!use_sw_pm)
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return 0;
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if (watchdog_active(wdd))
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return da9063_wdt_stop(wdd);
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return 0;
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}
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static int __maybe_unused da9063_wdt_resume(struct device *dev)
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{
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struct watchdog_device *wdd = dev_get_drvdata(dev);
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if (!use_sw_pm)
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return 0;
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if (watchdog_active(wdd))
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return da9063_wdt_start(wdd);
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return 0;
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}
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static SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops,
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da9063_wdt_suspend, da9063_wdt_resume);
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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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.pm = &da9063_wdt_pm_ops,
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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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