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From: Nat Gurumoorthy <natg@google.com>
To: Jean Delvare <khali@linux-fr.org>,
	Guenter Roeck <guenter.roeck@ericsson.com>,
	Wim Van Sebroeck <wim@iguana.be>,
	lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org
Cc: mikew@google.com, Nat Gurumoorthy <natg@google.com>
Subject: [PATCH v8 2/2] Use "request_muxed_region" in it87 hwmon drivers
Date: Fri,  6 May 2011 11:55:15 -0700	[thread overview]
Message-ID: <1304708115-10451-1-git-send-email-natg@google.com> (raw)
In-Reply-To: <1304707960-10178-1-git-send-email-natg@google.com>

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@google.com>
---

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


WARNING: multiple messages have this Message-ID (diff)
From: Nat Gurumoorthy <natg@google.com>
To: Jean Delvare <khali@linux-fr.org>,
	Guenter Roeck <guenter.roeck@ericsson.com>,
	Wim Van Sebroeck <wim@iguana.be>,
	lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org
Cc: mikew@google.com, Nat Gurumoorthy <natg@google.com>
Subject: [lm-sensors] [PATCH v8 2/2] Use "request_muxed_region" in it87
Date: Fri, 06 May 2011 18:55:15 +0000	[thread overview]
Message-ID: <1304708115-10451-1-git-send-email-natg@google.com> (raw)
In-Reply-To: <1304707960-10178-1-git-send-email-natg@google.com>

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@google.com>
---

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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  parent reply	other threads:[~2011-05-06 18:55 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-06 18:52 Nat Gurumoorthy
2011-05-06 18:52 ` [lm-sensors] (no subject) Nat Gurumoorthy
2011-05-06 18:54 ` [PATCH v8 1/2] Use "request_muxed_region" in it87 watchdog drivers Nat Gurumoorthy
2011-05-06 18:54   ` [lm-sensors] [PATCH v8 1/2] Use "request_muxed_region" in it87 Nat Gurumoorthy
2011-05-06 18:55 ` Nat Gurumoorthy [this message]
2011-05-06 18:55   ` [lm-sensors] [PATCH v8 2/2] " Nat Gurumoorthy
2011-05-06 19:13 ` Guenter Roeck
2011-05-06 19:13   ` [lm-sensors] (no subject) Guenter Roeck
2011-05-06 20:00   ` Natarajan Gurumoorthy
2011-05-06 20:00     ` [lm-sensors] (no subject) Natarajan Gurumoorthy
  -- strict thread matches above, loose matches on Subject: below --
2005-05-29 14:39 John WICKS
2008-09-23 13:29 ` gaming
2011-05-04  7:03 ` Jeremy Harmon
2011-05-10 18:53 ` Jeremy Harmon
2011-11-26 18:26 ` su_pyrow
2011-12-08 18:31 ` Guenter Roeck
2011-12-08 18:36 ` Guenter Roeck
2012-11-07 20:09 ` 郭�园
2012-12-04  7:22 ` Dok Sander
2013-08-23 23:53 ` Robert Hinson
2013-10-29 17:51 ` morgan chong

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