hwmon: f71882fg: use a muxed resource lock for the Super I/O port

Sleep while acquiring a resource lock on the Super I/O port. This should
prevent collisions from causing the hardware probe to fail with -EBUSY.

Signed-off-by: Giel van Schijndel <me@mortis.eu>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

1 files changed, 19 insertions, 13 deletions

diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c
index 537841ef44b9..75afb3b0e076 100644
--- a/drivers/hwmon/f71882fg.c
+++ b/drivers/hwmon/f71882fg.c
@@ -111,7 +111,7 @@ static struct platform_device *f71882fg_pdev;
 /* Super-I/O Function prototypes */
 static inline int superio_inb(int base, int reg);
 static inline int superio_inw(int base, int reg);
-static inline void superio_enter(int base);
+static inline int superio_enter(int base);
 static inline void superio_select(int base, int ld);
 static inline void superio_exit(int base);
 
@@ -861,11 +861,20 @@ static int superio_inw(int base, int reg)
         return val;
 }
 
-static inline void superio_enter(int base)
+static inline int superio_enter(int base)
 {
+        /* Don't step on other drivers' I/O space by accident */
+        if (!request_muxed_region(base, 2, DRVNAME)) {
+                printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
+                                base);
+                return -EBUSY;
+        }
+
         /* according to the datasheet the key must be send twice! */
         outb(SIO_UNLOCK_KEY, base);
         outb(SIO_UNLOCK_KEY, base);
+
+        return 0;
 }
 
 static inline void superio_select(int base, int ld)
@@ -877,6 +886,7 @@ static inline void superio_select(int base, int ld)
 static inline void superio_exit(int base)
 {
         outb(SIO_LOCK_KEY, base);
+        release_region(base, 2);
 }
 
 static inline int fan_from_reg(u16 reg)
@@ -2175,21 +2185,15 @@ static int f71882fg_remove(struct platform_device *pdev)
 static int __init f71882fg_find(int sioaddr, unsigned short *address,
         struct f71882fg_sio_data *sio_data)
 {
-        int err = -ENODEV;
         u16 devid;
-
-        /* Don't step on other drivers' I/O space by accident */
-        if (!request_region(sioaddr, 2, DRVNAME)) {
-                printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
-                                (int)sioaddr);
-                return -EBUSY;
-        }
-
-        superio_enter(sioaddr);
+        int err = superio_enter(sioaddr);
+        if (err)
+                return err;
 
         devid = superio_inw(sioaddr, SIO_REG_MANID);
         if (devid != SIO_FINTEK_ID) {
                 pr_debug(DRVNAME ": Not a Fintek device\n");
+                err = -ENODEV;
                 goto exit;
         }
 
@@ -2213,6 +2217,7 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
         default:
                 printk(KERN_INFO DRVNAME ": Unsupported Fintek device: %04x\n",
                        (unsigned int)devid);
+                err = -ENODEV;
                 goto exit;
         }
 
@@ -2223,12 +2228,14 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
 
         if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
                 printk(KERN_WARNING DRVNAME ": Device not activated\n");
+                err = -ENODEV;
                 goto exit;
         }
 
         *address = superio_inw(sioaddr, SIO_REG_ADDR);
         if (*address == 0) {
                 printk(KERN_WARNING DRVNAME ": Base address not set\n");
+                err = -ENODEV;
                 goto exit;
         }
         *address &= ~(REGION_LENGTH - 1);       /* Ignore 3 LSB */
@@ -2239,7 +2246,6 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
                 (int)superio_inb(sioaddr, SIO_REG_DEVREV));
 exit:
         superio_exit(sioaddr);
-        release_region(sioaddr, 2);
         return err;
 }