HID: intel_ish-hid: HBM: Use connected standby state bit during suspend/resume

The individual sensor drivers implemented in the ISH firmware needs
capability to take special actions when there is a change in the system
standby state. The ISH core firmware passes this notification to
individual sensor drivers in response to the OS request via connected
standby bit in the SYSTEM_STATE_STATUS command.

This change sets CONNECTED_STANDBY_STATE_BIT bit to 1 during suspend
callback and clears during resume callback.
Signed-off-by: Ye Xiang <xiang.ye@intel.com>
[srinivas.pandruvada@linux.intel.com: changelog rewrite]
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/intel-ish-hid/ishtp/hbm.c

@@ -914,7 +914,7 @@ static inline void fix_cl_hdr(struct ishtp_msg_hdr *hdr, size_t length,
 /*** Suspend and resume notification ***/
 
 static uint32_t current_state;
-static uint32_t supported_states = 0 | SUSPEND_STATE_BIT;
+static uint32_t supported_states = SUSPEND_STATE_BIT | CONNECTED_STANDBY_STATE_BIT;
 
 /**
  * ishtp_send_suspend() - Send suspend message to FW
@@ -933,7 +933,7 @@ void ishtp_send_suspend(struct ishtp_device *dev)
 	memset(&state_status_msg, 0, len);
 	state_status_msg.hdr.cmd = SYSTEM_STATE_STATUS;
 	state_status_msg.supported_states = supported_states;
-	current_state |= SUSPEND_STATE_BIT;
+	current_state |= (SUSPEND_STATE_BIT | CONNECTED_STANDBY_STATE_BIT);
 	dev->print_log(dev, "%s() sends SUSPEND notification\n", __func__);
 	state_status_msg.states_status = current_state;
 
@@ -959,7 +959,7 @@ void ishtp_send_resume(struct ishtp_device *dev)
 	memset(&state_status_msg, 0, len);
 	state_status_msg.hdr.cmd = SYSTEM_STATE_STATUS;
 	state_status_msg.supported_states = supported_states;
-	current_state &= ~SUSPEND_STATE_BIT;
+	current_state &= ~(CONNECTED_STANDBY_STATE_BIT | SUSPEND_STATE_BIT);
 	dev->print_log(dev, "%s() sends RESUME notification\n", __func__);
 	state_status_msg.states_status = current_state;
 

drivers/hid/intel-ish-hid/ishtp/hbm.h

@@ -235,6 +235,7 @@ struct dma_xfer_hbm {
 #define SYSTEM_STATE_QUERY_SUBSCRIBERS		0x3
 #define SYSTEM_STATE_STATE_CHANGE_REQ		0x4
 /*indicates suspend and resume states*/
+#define CONNECTED_STANDBY_STATE_BIT		(1<<0)
 #define SUSPEND_STATE_BIT			(1<<1)
 
 struct ish_system_states_header {