[RFC PATCH 1/4] power: reset: reboot-mode: Allow magic to be 0

[Elliot Berman]

Allow magic from the reboot-mode driver to be defined, but 0. This is
useful when the register/command to trigger reboot needs 0 to be
written. This is the case when the "default" reboot mode is to enter a
crash dump collection mode (e.g. when triggered by a watchdog) and Linux
doing a normal reboot requires the setting to be explicitly reset to
zero.

Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
 drivers/power/reset/reboot-mode.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index b4076b10b893..a646aefa041b 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -19,11 +19,10 @@ struct mode_info {
 	struct list_head list;
 };
 
-static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
-					  const char *cmd)
+static bool get_reboot_mode_magic(struct reboot_mode_driver *reboot,
+					  const char *cmd, unsigned int *magic)
 {
 	const char *normal = "normal";
-	int magic = 0;
 	struct mode_info *info;
 
 	if (!cmd)
@@ -31,12 +30,12 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 
 	list_for_each_entry(info, &reboot->head, list) {
 		if (!strcmp(info->mode, cmd)) {
-			magic = info->magic;
-			break;
+			*magic = info->magic;
+			return true;
 		}
 	}
 
-	return magic;
+	return false;
 }
 
 static int reboot_mode_notify(struct notifier_block *this,
@@ -46,8 +45,7 @@ static int reboot_mode_notify(struct notifier_block *this,
 	unsigned int magic;
 
 	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
-	magic = get_reboot_mode_magic(reboot, cmd);
-	if (magic)
+	if (get_reboot_mode_magic(reboot, cmd, &magic))
 		reboot->write(reboot, magic);
 
 	return NOTIFY_DONE;
-- 
2.41.0