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, 6 insertions, 0 deletions

diff --git a/drivers/staging/greybus/hd.c b/drivers/staging/greybus/hd.c
index 8ef849a..185ae3f 100644
--- a/drivers/staging/greybus/hd.c
+++ b/drivers/staging/greybus/hd.c
@@ -232,6 +232,12 @@ void gb_hd_del(struct gb_host_device *hd)
 }
 EXPORT_SYMBOL_GPL(gb_hd_del);
 
+void gb_hd_shutdown(struct gb_host_device *hd)
+{
+	gb_svc_del(hd->svc);
+}
+EXPORT_SYMBOL_GPL(gb_hd_shutdown);
+
 void gb_hd_put(struct gb_host_device *hd)
 {
 	put_device(&hd->dev);