mfd: rtsx_usb: Defer autosuspend while card exists

A card insertion happens after the lastest polling before reader is
suspended may never have a chance to be detected. Under current 1-HZ
polling interval setting in mmc_core, the worst case of such
undetectablility is about 1 second.

To further reduce the undetectability, detect card slot again in suspend
method and defer the autosuspend if the slot is loaded. The default 2
second autosuspend delay of USB subsystem should let the next polling
detects the card.

Signed-off-by: Roger Tseng <rogerable@realtek.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/rtsx_usb.c b/drivers/mfd/rtsx_usb.c
index 210d1f85679e50dca4cbb034d4bd4ce91c1bb23f..ede50244f265b14d950fba0448652960304fa971 100644 (file)
--- a/drivers/mfd/rtsx_usb.c
+++ b/drivers/mfd/rtsx_usb.c
@@ -681,9 +681,27 @@ static void rtsx_usb_disconnect(struct usb_interface *intf)
 #ifdef CONFIG_PM
 static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 {
+       struct rtsx_ucr *ucr =
+               (struct rtsx_ucr *)usb_get_intfdata(intf);
+       u16 val = 0;
+
        dev_dbg(&intf->dev, "%s called with pm message 0x%04x\n",
                        __func__, message.event);
 
+       if (PMSG_IS_AUTO(message)) {
+               if (mutex_trylock(&ucr->dev_mutex)) {
+                       rtsx_usb_get_card_status(ucr, &val);
+                       mutex_unlock(&ucr->dev_mutex);
+
+                       /* Defer the autosuspend if card exists */
+                       if (val & (SD_CD | MS_CD))
+                               return -EAGAIN;
+               } else {
+                       /* There is an ongoing operation*/
+                       return -EAGAIN;
+               }
+       }
+
        return 0;
 }