usb: ohci-at91: Forcibly suspend ports while USB suspend

The usb controller does not manage correctly the suspend mode for
the ehci. In echi mode, there is no way to suspend without any
device connected to it. This is why this specific control is added
to fix this issue. Since the suspend mode works in ohci mode, this
specific control works by suspend the usb controller in ohci mode.

This specific control is by setting the SUSPEND_A/B/C fields of
SFR_OHCIICR(OHCI Interrupt Configuration Register) in the SFR
while the OHCI USB suspend.

This set operation must be done before the USB clock disabled,
clear operation after the USB clock enabled.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index d177372..3110217 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -21,8 +21,11 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <soc/at91/atmel-sfr.h>
 
 #include "ohci.h"
 
@@ -51,6 +54,7 @@
 	struct clk *hclk;
 	bool clocked;
 	bool wakeup;		/* Saved wake-up state for resume */
+	struct regmap *sfr_regmap;
 };
 /* interface and function clocks; sometimes also an AHB clock */
 
@@ -134,6 +138,17 @@
 
 static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
 
+struct regmap *at91_dt_syscon_sfr(void)
+{
+	struct regmap *regmap;
+
+	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
+	if (IS_ERR(regmap))
+		regmap = NULL;
+
+	return regmap;
+}
+
 /* configure so an HC device and id are always provided */
 /* always called with process context; sleeping is OK */
 
@@ -197,6 +212,10 @@
 		goto err;
 	}
 
+	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
+	if (!ohci_at91->sfr_regmap)
+		dev_warn(dev, "failed to find sfr node\n");
+
 	board = hcd->self.controller->platform_data;
 	ohci = hcd_to_ohci(hcd);
 	ohci->num_ports = board->ports;
@@ -282,6 +301,28 @@
 	return length;
 }
 
+static int ohci_at91_port_suspend(struct regmap *regmap, u8 set)
+{
+	u32 regval;
+	int ret;
+
+	if (!regmap)
+		return 0;
+
+	ret = regmap_read(regmap, AT91_SFR_OHCIICR, &regval);
+	if (ret)
+		return ret;
+
+	if (set)
+		regval |= AT91_OHCIICR_USB_SUSPEND;
+	else
+		regval &= ~AT91_OHCIICR_USB_SUSPEND;
+
+	regmap_write(regmap, AT91_SFR_OHCIICR, regval);
+
+	return 0;
+}
+
 /*
  * Look at the control requests to the root hub and see if we need to override.
  */
@@ -289,6 +330,7 @@
 				 u16 wIndex, char *buf, u16 wLength)
 {
 	struct at91_usbh_data *pdata = dev_get_platdata(hcd->self.controller);
+	struct ohci_at91_priv *ohci_at91 = hcd_to_ohci_at91_priv(hcd);
 	struct usb_hub_descriptor *desc;
 	int ret = -EINVAL;
 	u32 *data = (u32 *)buf;
@@ -301,7 +343,8 @@
 
 	switch (typeReq) {
 	case SetPortFeature:
-		if (wValue == USB_PORT_FEAT_POWER) {
+		switch (wValue) {
+		case USB_PORT_FEAT_POWER:
 			dev_dbg(hcd->self.controller, "SetPortFeat: POWER\n");
 			if (valid_port(wIndex)) {
 				ohci_at91_usb_set_power(pdata, wIndex, 1);
@@ -309,6 +352,15 @@
 			}
 
 			goto out;
+
+		case USB_PORT_FEAT_SUSPEND:
+			dev_dbg(hcd->self.controller, "SetPortFeat: SUSPEND\n");
+			if (valid_port(wIndex)) {
+				ohci_at91_port_suspend(ohci_at91->sfr_regmap,
+						       1);
+				return 0;
+			}
+			break;
 		}
 		break;
 
@@ -342,6 +394,16 @@
 				ohci_at91_usb_set_power(pdata, wIndex, 0);
 				return 0;
 			}
+			break;
+
+		case USB_PORT_FEAT_SUSPEND:
+			dev_dbg(hcd->self.controller, "ClearPortFeature: SUSPEND\n");
+			if (valid_port(wIndex)) {
+				ohci_at91_port_suspend(ohci_at91->sfr_regmap,
+						       0);
+				return 0;
+			}
+			break;
 		}
 		break;
 	}
@@ -599,6 +661,8 @@
 	if (ohci_at91->wakeup)
 		enable_irq_wake(hcd->irq);
 
+	ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
+
 	ret = ohci_suspend(hcd, ohci_at91->wakeup);
 	if (ret) {
 		if (ohci_at91->wakeup)
@@ -638,6 +702,9 @@
 	at91_start_clock(ohci_at91);
 
 	ohci_resume(hcd, false);
+
+	ohci_at91_port_suspend(ohci_at91->sfr_regmap, 0);
+
 	return 0;
 }