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authorNat Gurumoorthy <natg@google.com>2011-05-25 22:43:33 +0400
committerJean Delvare <khali@endymion.delvare>2011-05-25 22:43:33 +0400
commit5b0380c94a2e888b7858fbec6fc3ac623bc9b05a (patch)
tree25bfaf2ab49a7b5284dd0bb04f5d6b100fe65282 /drivers/hwmon/it87.c
parent357b9dc6c2dbb01e835415355b70d6b47c43a102 (diff)
downloadlinux-5b0380c94a2e888b7858fbec6fc3ac623bc9b05a.tar.xz
hwmon: (it87) Use request_muxed_region
Serialize access to the hardware by using "request_muxed_region" macro defined by Alan Cox. Call to this macro will hold off the requestor if the resource is currently busy. "superio_enter" will return an error if call to "request_muxed_region" fails. Rest of the code change is to ripple an error return from superio_enter to the top level. Signed-off-by: Nat Gurumoorthy <natg@google.com> Acked-by: Guenter Roeck <guenter.roeck@ericsson.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/hwmon/it87.c')
-rw-r--r--drivers/hwmon/it87.c31
1 files changed, 19 insertions, 12 deletions
diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 316b64823f7b..bb6405b92007 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -77,15 +77,13 @@ static struct platform_device *pdev;
#define DEVID 0x20 /* Register: Device ID */
#define DEVREV 0x22 /* Register: Device Revision */
-static inline int
-superio_inb(int reg)
+static inline int superio_inb(int reg)
{
outb(reg, REG);
return inb(VAL);
}
-static inline void
-superio_outb(int reg, int val)
+static inline void superio_outb(int reg, int val)
{
outb(reg, REG);
outb(val, VAL);
@@ -101,27 +99,32 @@ static int superio_inw(int reg)
return val;
}
-static inline void
-superio_select(int ldn)
+static inline void superio_select(int ldn)
{
outb(DEV, REG);
outb(ldn, VAL);
}
-static inline void
-superio_enter(void)
+static inline int superio_enter(void)
{
+ /*
+ * Try to reserve REG and REG + 1 for exclusive access.
+ */
+ if (!request_muxed_region(REG, 2, DRVNAME))
+ return -EBUSY;
+
outb(0x87, REG);
outb(0x01, REG);
outb(0x55, REG);
outb(0x55, REG);
+ return 0;
}
-static inline void
-superio_exit(void)
+static inline void superio_exit(void)
{
outb(0x02, REG);
outb(0x02, VAL);
+ release_region(REG, 2);
}
/* Logical device 4 registers */
@@ -1542,11 +1545,15 @@ static const struct attribute_group it87_group_label = {
static int __init it87_find(unsigned short *address,
struct it87_sio_data *sio_data)
{
- int err = -ENODEV;
+ int err;
u16 chip_type;
const char *board_vendor, *board_name;
- superio_enter();
+ err = superio_enter();
+ if (err)
+ return err;
+
+ err = -ENODEV;
chip_type = force_id ? force_id : superio_inw(DEVID);
switch (chip_type) {