greybus: loopback: add runtime pm support

Add runtime pm to the loopback driver so that
the module wakes up from suspend while a test
is executed.

Testing Done: Let the module enter standby and
execute a loopback test.

Signed-off-by: Axel Haslam <haslam_axel@projectara.com>
Signed-off-by: David Lin <dtwlin@google.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Alex Elder <elder@linaro.org>

diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
index 702cf069eefd303a8a4cf00094385d762c84dc52..8b0d0dc2ed8bc2c7a6fa8ade74a56d15f9d575bd 100644 (file)
--- a/drivers/staging/greybus/loopback.c
+++ b/drivers/staging/greybus/loopback.c
@@ -25,6 +25,7 @@
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 #include <linux/atomic.h>
+#include <linux/pm_runtime.h>
 
 #include <asm/div64.h>
 
@@ -976,14 +977,26 @@ static int gb_loopback_fn(void *data)
        int error = 0;
        int us_wait = 0;
        int type;
+       int ret;
        u32 size;
 
        struct gb_loopback *gb = data;
+       struct gb_bundle *bundle = gb->connection->bundle;
+
+       ret = gb_pm_runtime_get_sync(bundle);
+       if (ret)
+               return ret;
 
        while (1) {
-               if (!gb->type)
+               if (!gb->type) {
+                       gb_pm_runtime_put_autosuspend(bundle);
                        wait_event_interruptible(gb->wq, gb->type ||
                                                 kthread_should_stop());
+                       ret = gb_pm_runtime_get_sync(bundle);
+                       if (ret)
+                               return ret;
+               }
+
                if (kthread_should_stop())
                        break;
 
@@ -1042,6 +1055,9 @@ static int gb_loopback_fn(void *data)
                if (us_wait)
                        udelay(us_wait);
        }
+
+       gb_pm_runtime_put_autosuspend(bundle);
+
        return 0;
 }
 
@@ -1233,6 +1249,9 @@ static int gb_loopback_probe(struct gb_bundle *bundle,
        spin_unlock_irqrestore(&gb_dev.lock, flags);
 
        gb_connection_latency_tag_enable(connection);
+
+       gb_pm_runtime_put_autosuspend(bundle);
+
        return 0;
 
 out_kfifo1:
@@ -1259,6 +1278,11 @@ static void gb_loopback_disconnect(struct gb_bundle *bundle)
 {
        struct gb_loopback *gb = greybus_get_drvdata(bundle);
        unsigned long flags;
+       int ret;
+
+       ret = gb_pm_runtime_get_sync(bundle);
+       if (ret)
+               gb_pm_runtime_get_noresume(bundle);
 
        gb_connection_disable(gb->connection);