regulator: Use driver_deferred_probe_timeout for regulator_init_complete_work

The regulator_init_complete_work logic defers the cleanup for an
arbitrary 30 seconds of time to allow modules loaded by userland
to start.

This arbitrary timeout is similar to the
driver_deferred_probe_timeout value, and its been suggested we
align these so users have a method to extend the timeouts as
needed.

So this patch changes the logic to use the
driver_deferred_probe_timeout value for the delay value if it
is set (using a delay of 0 if it is not).

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-7-john.stultz@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/regulator/core.c

@@ -5757,6 +5757,10 @@ static DECLARE_DELAYED_WORK(regulator_init_complete_work,
 
 static int __init regulator_init_complete(void)
 {
+	int delay = driver_deferred_probe_timeout;
+
+	if (delay < 0)
+		delay = 0;
 	/*
 	 * Since DT doesn't provide an idiomatic mechanism for
 	 * enabling full constraints and since it's much more natural
@@ -5767,18 +5771,17 @@ static int __init regulator_init_complete(void)
 		has_full_constraints = true;
 
 	/*
-	 * We punt completion for an arbitrary amount of time since
-	 * systems like distros will load many drivers from userspace
-	 * so consumers might not always be ready yet, this is
-	 * particularly an issue with laptops where this might bounce
-	 * the display off then on.  Ideally we'd get a notification
-	 * from userspace when this happens but we don't so just wait
-	 * a bit and hope we waited long enough.  It'd be better if
-	 * we'd only do this on systems that need it, and a kernel
-	 * command line option might be useful.
+	 * If driver_deferred_probe_timeout is set, we punt
+	 * completion for that many seconds since systems like
+	 * distros will load many drivers from userspace so consumers
+	 * might not always be ready yet, this is particularly an
+	 * issue with laptops where this might bounce the display off
+	 * then on.  Ideally we'd get a notification from userspace
+	 * when this happens but we don't so just wait a bit and hope
+	 * we waited long enough.  It'd be better if we'd only do
+	 * this on systems that need it.
 	 */
-	schedule_delayed_work(&regulator_init_complete_work,
-			      msecs_to_jiffies(30000));
+	schedule_delayed_work(&regulator_init_complete_work, delay * HZ);
 
 	return 0;
 }