linux-kernel - [PATCH] hwmon: f71882fg: properly acquire I/O regions while probing

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Date:	Tue, 23 Mar 2010 15:12:15 +0100
From:	Giel van Schijndel <me@...tis.eu>
To:	Hans de Goede <hdegoede@...hat.com>
Cc:	Jean Delvare <khali@...ux-fr.org>,
	Giel van Schijndel <me@...tis.eu>,
	Jonathan Cameron <jic23@....ac.uk>,
	Laurens Leemans <laurens@...nips.com>,
	lm-sensors@...sensors.org, linux-kernel@...r.kernel.org
Subject: [PATCH] hwmon: f71882fg: properly acquire I/O regions while probing

Acquire the I/O region for the Super I/O chip while we're working on it.

Further alter the way multiple Super I/O addresses are probed for chips
such that errors in the probing process are passed on from the module
initialisation function.

Some code cleanup: properly using, previously defined, functions rather
than duplicating their code.
---
 drivers/hwmon/f71882fg.c |   38 +++++++++++++++++++++++---------------
 1 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c
index 4230729..25e1cad 100644
--- a/drivers/hwmon/f71882fg.c
+++ b/drivers/hwmon/f71882fg.c
@@ -856,10 +856,8 @@ static inline int superio_inb(int base, int reg)
 static int superio_inw(int base, int reg)
 {
 	int val;
-	outb(reg++, base);
-	val = inb(base + 1) << 8;
-	outb(reg, base);
-	val |= inb(base + 1);
+	val  = superio_inb(base, reg) << 8;
+	val |= superio_inb(base, reg + 1);
 	return val;
 }
 
@@ -905,10 +903,8 @@ static u16 f71882fg_read16(struct f71882fg_data *data, u8 reg)
 {
 	u16 val;
 
-	outb(reg++, data->addr + ADDR_REG_OFFSET);
-	val = inb(data->addr + DATA_REG_OFFSET) << 8;
-	outb(reg, data->addr + ADDR_REG_OFFSET);
-	val |= inb(data->addr + DATA_REG_OFFSET);
+	val  = f71882fg_read8(data, reg) << 8;
+	val |= f71882fg_read8(data, reg + 1);
 
 	return val;
 }
@@ -921,10 +917,8 @@ static void f71882fg_write8(struct f71882fg_data *data, u8 reg, u8 val)
 
 static void f71882fg_write16(struct f71882fg_data *data, u8 reg, u16 val)
 {
-	outb(reg++, data->addr + ADDR_REG_OFFSET);
-	outb(val >> 8, data->addr + DATA_REG_OFFSET);
-	outb(reg, data->addr + ADDR_REG_OFFSET);
-	outb(val & 255, data->addr + DATA_REG_OFFSET);
+	f71882fg_write8(data, reg,     val >> 8);
+	f71882fg_write8(data, reg + 1, val & 0xff);
 }
 
 static u16 f71882fg_read_temp(struct f71882fg_data *data, int nr)
@@ -2184,6 +2178,13 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
 	int err = -ENODEV;
 	u16 devid;
 
+	/* Don't step on other driver's I/O space by accident */
+	if (!request_region(sioaddr, 2, DRVNAME)) {
+		printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
+				(int)sioaddr);
+		return -EIO;
+	}
+
 	superio_enter(sioaddr);
 
 	devid = superio_inw(sioaddr, SIO_REG_MANID);
@@ -2238,6 +2239,7 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
 		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
 exit:
 	superio_exit(sioaddr);
+	release_region(sioaddr, 2);
 	return err;
 }
 
@@ -2289,14 +2291,20 @@ exit_device_put:
 
 static int __init f71882fg_init(void)
 {
+	static const unsigned short addrs[] = { 0x2e, 0x4e };
 	int err = -ENODEV;
-	unsigned short address;
+	unsigned short address = /* shut up compiler */ 0;
 	struct f71882fg_sio_data sio_data;
+	int i;
 
 	memset(&sio_data, 0, sizeof(sio_data));
 
-	if (f71882fg_find(0x2e, &address, &sio_data) &&
-	    f71882fg_find(0x4e, &address, &sio_data))
+	for (i = 0; i < ARRAY_SIZE(addrs); i++) {
+		err = f71882fg_find(addrs[i], &address, &sio_data);
+		if (err == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(addrs))
 		goto exit;
 
 	err = platform_driver_register(&f71882fg_driver);
-- 
1.6.4.4

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