This patch ensures our parent is awake before a reboot takes place. This prevents situations in which the I2C host has been suspended and cannot be safely woken up anymore when it needs to talk to us. Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx> --- Hi! This is supposed to resolve the issue that came up in the review of "[PATCH v2] i2c: sh_mobile: implement atomic transfers" that the parent controller may be suspended when the restart method is called. See https://www.spinics.net/lists/linux-i2c/msg46367.html for details. CU Uli drivers/watchdog/da9063_wdt.c | 21 +++++++++++++++++++++ include/linux/mfd/da9063/core.h | 2 ++ 2 files changed, 23 insertions(+) diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c index 423584252606..89718733491e 100644 --- a/drivers/watchdog/da9063_wdt.c +++ b/drivers/watchdog/da9063_wdt.c @@ -18,6 +18,8 @@ #include <linux/mfd/da9063/registers.h> #include <linux/mfd/da9063/core.h> #include <linux/regmap.h> +#include <linux/pm_runtime.h> +#include <linux/reboot.h> /* * Watchdog selector to timeout in seconds. @@ -158,6 +160,21 @@ static int da9063_wdt_set_timeout(struct watchdog_device *wdd, return ret; } +static int da9063_reboot_notifier(struct notifier_block *nb, + unsigned long code, void *unused) +{ + struct da9063 *da9063 = container_of(nb, struct da9063, reboot_nb); + + /* + * Make sure parent device is running. This cannot be done in the + * restart handler because it is no longer safe to do runtime PM + * there. + */ + pm_runtime_get_sync(da9063->dev->parent); + + return NOTIFY_DONE; +} + static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, void *data) { @@ -233,6 +250,10 @@ static int da9063_wdt_probe(struct platform_device *pdev) set_bit(WDOG_HW_RUNNING, &wdd->status); } + /* Get early notification of reboot so we can wake up the parent. */ + da9063->reboot_nb.notifier_call = da9063_reboot_notifier; + devm_register_reboot_notifier(dev, &da9063->reboot_nb); + return devm_watchdog_register_device(dev, wdd); } diff --git a/include/linux/mfd/da9063/core.h b/include/linux/mfd/da9063/core.h index fa7a43f02f27..9a3283d488b7 100644 --- a/include/linux/mfd/da9063/core.h +++ b/include/linux/mfd/da9063/core.h @@ -85,6 +85,8 @@ struct da9063 { int chip_irq; unsigned int irq_base; struct regmap_irq_chip_data *regmap_irq; + + struct notifier_block reboot_nb; }; int da9063_device_init(struct da9063 *da9063, unsigned int irq); -- 2.20.1
