greybus: hd: arche-platform: implement greybus shutdown

Implement platform driver shutdown callback to perform proper greybus
shutdown so that the userspace unipro_shutdown service that shuts down
the APB/SVC abruptly can be removed. The shutdown callback in
arche-platform will first remove SVC so that all the Interface can be
Deactivated in a sequence according to the spec before powering off the
APB:

Before:
 -> Arche/APB power off
 -> SoC power off

After this patch:
 -> HD shutdown
     -> SVC shutdown
         -> Module shutdown
             -> Interface shutdown
                 -> Bundle shutdown
 -> Arche/APB power off
 -> SoC power off

Testing Done:
 - Observe all Interfaces are deactivated in the log during shutdown
 - Measure power off current and make sure no regression

Signed-off-by: David Lin <dtwlin@google.com>
Reviewed-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/staging/greybus/core.c b/drivers/staging/greybus/core.c
index 53d9ba151aeb..2c94bbb1748f 100644
--- a/drivers/staging/greybus/core.c
+++ b/drivers/staging/greybus/core.c
@@ -146,10 +146,21 @@ static int greybus_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static void greybus_shutdown(struct device *dev)
+{
+	if (is_gb_host_device(dev)) {
+		struct gb_host_device *hd;
+
+		hd = to_gb_host_device(dev);
+		gb_hd_shutdown(hd);
+	}
+}
+
 struct bus_type greybus_bus_type = {
 	.name =		"greybus",
 	.match =	greybus_match_device,
 	.uevent =	greybus_uevent,
+	.shutdown =	greybus_shutdown,
 };
 
 static int greybus_probe(struct device *dev)