usb: dwc3: Support option to disable USB2 LPM

Support the option to disable USB2 LPM. Set xhci "usb2-lpm-disable"
property via "snps,usb2-lpm-disable" property.
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -1248,6 +1248,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				&hird_threshold);
 	dwc->usb3_lpm_capable = device_property_read_bool(dev,
 				"snps,usb3_lpm_capable");
+	dwc->usb2_lpm_disable = device_property_read_bool(dev,
+				"snps,usb2-lpm-disable");
 	device_property_read_u8(dev, "snps,rx-thr-num-pkt-prd",
 				&rx_thr_num_pkt_prd);
 	device_property_read_u8(dev, "snps,rx-max-burst-prd",

drivers/usb/dwc3/core.h

@@ -982,6 +982,7 @@ struct dwc3_scratchpad_array {
  * @setup_packet_pending: true when there's a Setup Packet in FIFO. Workaround
  * @three_stage_setup: set if we perform a three phase setup
  * @usb3_lpm_capable: set if hadrware supports Link Power Management
+ * @usb2_lpm_disable: set to disable usb2 lpm
  * @disable_scramble_quirk: set if we enable the disable scramble quirk
  * @u2exit_lfps_quirk: set if we enable u2exit lfps quirk
  * @u2ss_inp3_quirk: set if we enable P3 OK for U2/SS Inactive quirk
@@ -1159,6 +1160,7 @@ struct dwc3 {
 	unsigned		setup_packet_pending:1;
 	unsigned		three_stage_setup:1;
 	unsigned		usb3_lpm_capable:1;
+	unsigned		usb2_lpm_disable:1;
 
 	unsigned		disable_scramble_quirk:1;
 	unsigned		u2exit_lfps_quirk:1;

drivers/usb/dwc3/host.c

@@ -46,7 +46,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
 
 int dwc3_host_init(struct dwc3 *dwc)
 {
-	struct property_entry	props[3];
+	struct property_entry	props[4];
 	struct platform_device	*xhci;
 	int			ret, irq;
 	struct resource		*res;
@@ -93,6 +93,9 @@ int dwc3_host_init(struct dwc3 *dwc)
 	if (dwc->usb3_lpm_capable)
 		props[prop_idx++].name = "usb3-lpm-capable";
 
+	if (dwc->usb2_lpm_disable)
+		props[prop_idx++].name = "usb2-lpm-disable";
+
 	/**
 	 * WORKAROUND: dwc3 revisions <=3.00a have a limitation
 	 * where Port Disable command doesn't work.