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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>
This commit is contained in:
Nat Gurumoorthy 2011-05-25 20:43:33 +02:00 committed by Jean Delvare
parent 357b9dc6c2
commit 5b0380c94a
1 changed files with 19 additions and 12 deletions
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31
drivers/hwmon/it87.c
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@ -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) {