greybus: control: add interface suspend prepare operation

Add the AP implementation for the Greybus Control Interface Suspend
Prepare Operation. AP uses this Operation during the Suspend transition
to request the Interface to enter a low-power mode after it detects a
subsequent UniPro link hibernation.

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/control.c b/drivers/staging/greybus/control.c
index a53fa3d68280de2886e7085983cd757790f1f455..252352ce366459300f83206ceda524b3a6d4038b 100644 (file)
--- a/drivers/staging/greybus/control.c
+++ b/drivers/staging/greybus/control.c
@@ -348,6 +348,41 @@ int gb_control_bundle_activate(struct gb_control *control, u8 bundle_id)
        return 0;
 }
 
+static int gb_control_interface_pm_status_map(u8 status)
+{
+       switch (status) {
+       case GB_CONTROL_INTF_PM_BUSY:
+               return -EBUSY;
+       case GB_CONTROL_INTF_PM_NA:
+               return -ENOMSG;
+       default:
+               return -EREMOTEIO;
+       }
+}
+
+int gb_control_interface_suspend_prepare(struct gb_control *control)
+{
+       struct gb_control_intf_pm_response response;
+       int ret;
+
+       ret = gb_operation_sync(control->connection,
+                               GB_CONTROL_TYPE_INTF_SUSPEND_PREPARE, NULL, 0,
+                               &response, sizeof(response));
+       if (ret) {
+               dev_err(&control->dev,
+                       "failed to send interface suspend prepare: %d\n", ret);
+               return ret;
+       }
+
+       if (response.status != GB_CONTROL_INTF_PM_OK) {
+               dev_err(&control->dev, "interface error while preparing suspend: %d\n",
+                       response.status);
+               return gb_control_interface_pm_status_map(response.status);
+       }
+
+       return 0;
+}
+
 static ssize_t vendor_string_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
 {

diff --git a/drivers/staging/greybus/control.h b/drivers/staging/greybus/control.h
index 5ddf0138c6c5538895bd982c446f2b829c54baca..bc32ca78d2256e7d33b62484abc72e963fb72a47 100644 (file)
--- a/drivers/staging/greybus/control.h
+++ b/drivers/staging/greybus/control.h
@@ -56,4 +56,5 @@ int gb_control_bundle_suspend(struct gb_control *control, u8 bundle_id);
 int gb_control_bundle_resume(struct gb_control *control, u8 bundle_id);
 int gb_control_bundle_deactivate(struct gb_control *control, u8 bundle_id);
 int gb_control_bundle_activate(struct gb_control *control, u8 bundle_id);
+int gb_control_interface_suspend_prepare(struct gb_control *control);
 #endif /* __CONTROL_H */

diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h
index 1ae335040139854c31aefc12e545476a4bbff8d4..cd64a99debfa113d692be44dccedf93794a27a07 100644 (file)
--- a/drivers/staging/greybus/greybus_protocols.h
+++ b/drivers/staging/greybus/greybus_protocols.h
@@ -130,6 +130,7 @@ struct gb_protocol_version_response {
 #define GB_CONTROL_TYPE_BUNDLE_RESUME          0x10
 #define GB_CONTROL_TYPE_BUNDLE_DEACTIVATE      0x11
 #define GB_CONTROL_TYPE_BUNDLE_ACTIVATE                0x12
+#define GB_CONTROL_TYPE_INTF_SUSPEND_PREPARE           0x13
 
 struct gb_control_version_request {
        __u8    major;
@@ -214,6 +215,20 @@ struct gb_control_bundle_pm_response {
        __u8    status;
 } __packed;
 
+/*
+ * Interface Suspend Prepare and Deactivate Prepare operations use the same
+ * response layout and error codes. Define a single response structure and reuse
+ * it. Both operations have no payload.
+ */
+
+#define GB_CONTROL_INTF_PM_OK          0x00
+#define GB_CONTROL_INTF_PM_BUSY                0x01
+#define GB_CONTROL_INTF_PM_NA          0x02
+
+struct gb_control_intf_pm_response {
+       __u8    status;
+} __packed;
+
 /* APBridge protocol */
 
 /* request APB1 log */