02 - Chages to hwmon it87 driver to 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@xxxxxxxxxx>
---
diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 316b648..fa3ff02 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -108,13 +108,20 @@ superio_select(int ldn)
outb(ldn, VAL);
}
-static inline 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
@@ -122,6 +129,7 @@ superio_exit(void)
{
outb(0x02, REG);
outb(0x02, VAL);
+ release_region(REG, 2);
}
/* Logical device 4 registers */
@@ -1546,7 +1554,9 @@ static int __init it87_find(unsigned short *address,
u16 chip_type;
const char *board_vendor, *board_name;
- superio_enter();
+ if (superio_enter())
+ return -EBUSY;
+
chip_type = force_id ? force_id : superio_inw(DEVID);
switch (chip_type) {
--
1.7.3.1
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