diff options
| author | Nat Gurumoorthy <natg@google.com> | 2011-05-25 20:43:33 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@endymion.delvare> | 2011-05-25 20:43:33 +0200 |
| commit | 5b0380c94a2e888b7858fbec6fc3ac623bc9b05a (patch) | |
| tree | 25bfaf2ab49a7b5284dd0bb04f5d6b100fe65282 /drivers/hwmon | |
| parent | hwmon: (sch5627) Trigger Vbat measurements (diff) | |
| download | linux-5b0380c94a2e888b7858fbec6fc3ac623bc9b05a.tar.xz linux-5b0380c94a2e888b7858fbec6fc3ac623bc9b05a.zip | |
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')
| -rw-r--r-- | drivers/hwmon/it87.c | 31 |
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) { |