[i2c] Can not find sensors since kernel 2.6.18

[Wang Xu]

On Sun, Apr 29, 2007 at 11:58:54AM +0800, gnawux wrote:
> I have a ASUS M2Ne Laptop, which has Intel ICH4 (i2c-i801) SMBus.
> 
> But under 2.6.18 and 2.6.20 kernel, no sensors could be found,
> I enable the debug option of 2.6.20 kernel, and found the following
> error message of i2c bus:
>  | PCI: Unable to reserve I/O region #5:20 at e800 for device 0000:00:1f.3
>  | i801_smbus 0000:00:1f.3: Failed to request SMBus region 0xe800-0xe81f
>  | i801_smbus: probe of 0000:00:1f.3 failed with error -16
> 
It works again!

I reviewed the codes and found they employed different PCI access way
between 2.6.16 and later kernel. I did not know the different the ways,
and had never written kernel modules before.

Anyway, I changed i2c-i801.c codes in 2.6.20 to 2.6.16 ways and the 
now the sensor data could be read again! Just the same as under 2.6.16 
kernel:
 | gnawux at inspiration:~$ sensors 
 | max6657-i2c-0-4c
 | Adapter: SMBus I801 adapter at e800
 | M/B Temp:    +49°C  (low  =   -55°C, high =  +127°C)   
 | CPU Temp:  +48.8°C  (low  = -54.1°C, high = +51.1°C)   
 | M/B Crit:   +127°C  (hyst =  +117°C)                   
 | CPU Crit:   +127°C  (hyst =  +117°C)   

Could anyone tell the different of the two ways? 

And the diff file are attached. (Actually I onle introduced some
2.6.16 codes to 2.6.20)

Thank you!

Wang Xu
-------------- next part --------------
--- i2c-i801.c.bak	2007-04-30 11:31:02.000000000 +0800
+++ i2c-i801.c	2007-05-01 07:49:29.000000000 +0800
@@ -69,6 +69,9 @@
 /* PCI Address Constants */
 #define SMBBAR		4
 #define SMBHSTCFG	0x040
+/* The following 2 lines are from 2.6.16 kernel. --gnawux */
+#define SMBBA		0x020
+#define SMBREV		0x008
 
 /* Host configuration bits for SMBHSTCFG */
 #define SMBHSTCFG_HST_EN	1
@@ -97,7 +100,10 @@
 static int i801_block_transaction(union i2c_smbus_data *data, char read_write,
 				  int command, int hwpec);
 
+/* it's short in 2.6.16 kernel. --gnawux 
 static unsigned long i801_smba;
+*/
+static unsigned short i801_smba;
 static struct pci_driver i801_driver;
 static struct pci_dev *I801_dev;
 static int isich4;
@@ -485,14 +491,33 @@
 		isich4 = 0;
 	}
 
+	pci_read_config_word(I801_dev, SMBBA, &i801_smba);
+	i801_smba &= 0xfff0;
+	if(i801_smba == 0) {
+		dev_err(&dev->dev, "SMB base address uninitialized "
+				"- upgrade BIOS or use force_addr=0xaddr\n");
+		return -ENODEV;
+	}/* above lines are copied from 2.6.16. --gnawux */
+
+	if (!request_region(i801_smba, (isich4 ? 16 : 8), i801_driver.name)) {
+		dev_err(&dev->dev, "I801_smb region 0x%x already in use!\n",
+				i801_smba);
+		err = -EBUSY;
+		goto exit;
+	} /* if section from 2.6.16, with changing END to exit. --gnawux */
+
+/*
 	err = pci_enable_device(dev);
 	if (err) {
 		dev_err(&dev->dev, "Failed to enable SMBus PCI device (%d)\n",
 			err);
 		goto exit;
 	}
+comment out. --gnawux
+*/
 
 	/* Determine the address of the SMBus area */
+/*
 	i801_smba = pci_resource_start(dev, SMBBAR);
 	if (!i801_smba) {
 		dev_err(&dev->dev, "SMBus base address uninitialized, "
@@ -500,7 +525,10 @@
 		err = -ENODEV;
 		goto exit;
 	}
+comment out. --gnawux
+*/
 
+/*
 	err = pci_request_region(dev, SMBBAR, i801_driver.name);
 	if (err) {
 		dev_err(&dev->dev, "Failed to request SMBus region "
@@ -508,6 +536,8 @@
 			(unsigned long long)pci_resource_end(dev, SMBBAR));
 		goto exit;
 	}
+comment out. --gnawux
+*/
 
 	pci_read_config_byte(I801_dev, SMBHSTCFG, &temp);
 	temp &= ~SMBHSTCFG_I2C_EN;	/* SMBus timing */
@@ -526,7 +556,7 @@
 	i801_adapter.dev.parent = &dev->dev;
 
 	snprintf(i801_adapter.name, I2C_NAME_SIZE,
-		"SMBus I801 adapter at %04lx", i801_smba);
+		"SMBus I801 adapter at %04x", i801_smba); /* change 04lx to 04x. --gnawux */
 	err = i2c_add_adapter(&i801_adapter);
 	if (err) {
 		dev_err(&dev->dev, "Failed to add SMBus adapter\n");
@@ -543,7 +573,14 @@
 static void __devexit i801_remove(struct pci_dev *dev)
 {
 	i2c_del_adapter(&i801_adapter);
+	
+	release_region(i801_smba, (isich4 ? 16 : 8));
+	/* the above line is copied from 2.6.16. --gnawux */
+
+/*
 	pci_release_region(dev, SMBBAR);
+comment out. --gnawux
+*/
 	/*
 	 * do not call pci_disable_device(dev) since it can cause hard hangs on
 	 * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010)