Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging

Pull i2c updates from Jean Delvare:
 "The most important changes here are a big cleanup of the i2c-piix4
  driver, cleanups and interrupt support to the i2c-i801 driver, and
  support for the SCCB protocol."

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c-omap: Add support for I2C_M_STOP message flag
  i2c: Fall back to emulated SMBus if the operation isn't supported natively
  i2c: Add SCCB support
  i2c-tiny-usb: Add support for the Robofuzz OSIF USB/I2C converter
  i2c-i801: Enable IRQ for byte_by_byte transactions
  i2c-i801: Enable interrupts on ICH5/7/8/9/10
  i2c-i801: Enable IRQ for SMBus transactions
  i2c-i801: Consolidate polling
  i2c-i801: Drop ENABLE_INT9
  i2c-i801: Rename some SMBHSTCNT bit constants
  i2c-i801: Check and return errors during byte-by-byte transfers
  i2c-i801: Clear only status bits in HST_STS
  i2c-i801: Refactor use of LAST_BYTE in i801_block_transaction_byte_by_byte
  i2c-smbus: Use module_i2c_driver()
  i2c/writing-clients: Mention module_i2c_driver()
  i2c-piix4: Support AMD auxiliary SMBus controller
  i2c-piix4: Separate registration and probing code
  i2c-piix4: Eliminate piix4_smba global variable
  i2c/busses: Use module_pci_driver
  i2c: Update Guenter Roeck's e-mail address

29 files changed, 487 insertions, 366 deletions

diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801
index 71f55bbcefc..615142da4ef 100644
--- a/Documentation/i2c/busses/i2c-i801
+++ b/Documentation/i2c/busses/i2c-i801
@@ -38,9 +38,10 @@ Module Parameters
 Disable selected features normally supported by the device. This makes it
 possible to work around possible driver or hardware bugs if the feature in
 question doesn't work as intended for whatever reason. Bit values:
-  1  disable SMBus PEC
-  2  disable the block buffer
-  8  disable the I2C block read functionality
+ 0x01  disable SMBus PEC
+ 0x02  disable the block buffer
+ 0x08  disable the I2C block read functionality
+ 0x10  don't use interrupts
 
 
 Description
@@ -86,6 +87,12 @@ SMBus 2.0 Support
 The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
 
 
+Interrupt Support
+-----------------
+
+PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
+
+
 Hidden ICH SMBus
 ----------------
 
diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4
index 475bb4ae072..1e6634f54c5 100644
--- a/Documentation/i2c/busses/i2c-piix4
+++ b/Documentation/i2c/busses/i2c-piix4
@@ -8,6 +8,11 @@ Supported adapters:
     Datasheet: Only available via NDA from ServerWorks
   * ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges
     Datasheet: Not publicly available
+    SB700 register reference available at:
+    http://support.amd.com/us/Embedded_TechDocs/43009_sb7xx_rrg_pub_1.00.pdf
+  * AMD SP5100 (SB700 derivative found on some server mainboards)
+    Datasheet: Publicly available at the AMD website
+    http://support.amd.com/us/Embedded_TechDocs/44413.pdf
   * AMD Hudson-2
     Datasheet: Not publicly available
   * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
@@ -68,6 +73,10 @@ this driver on those mainboards.
 The ServerWorks Southbridges, the Intel 440MX, and the Victory66 are
 identical to the PIIX4 in I2C/SMBus support.
 
+The AMD SB700 and SP5100 chipsets implement two PIIX4-compatible SMBus
+controllers. If your BIOS initializes the secondary controller, it will
+be detected by this driver as an "Auxiliary SMBus Host Controller".
+
 If you own Force CPCI735 motherboard or other OSB4 based systems you may need
 to change the SMBus Interrupt Select register so the SMBus controller uses
 the SMI mode.
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index 5aa53374ea2..3a94b0e6f60 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -245,21 +245,17 @@ static int __init foo_init(void)
 {
 	return i2c_add_driver(&foo_driver);
 }
+module_init(foo_init);
 
 static void __exit foo_cleanup(void)
 {
 	i2c_del_driver(&foo_driver);
 }
+module_exit(foo_cleanup);
 
-/* Substitute your own name and email address */
-MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"
-MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices");
-
-/* a few non-GPL license types are also allowed */
-MODULE_LICENSE("GPL");
+The module_i2c_driver() macro can be used to reduce above code.
 
-module_init(foo_init);
-module_exit(foo_cleanup);
+module_i2c_driver(foo_driver);
 
 Note that some functions are marked by `__init'.  These functions can
 be removed after kernel booting (or module loading) is completed.
@@ -267,6 +263,17 @@ Likewise, functions marked by `__exit' are dropped by the compiler when
 the code is built into the kernel, as they would never be called.
 
 
+Driver Information
+==================
+
+/* Substitute your own name and email address */
+MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"
+MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices");
+
+/* a few non-GPL license types are also allowed */
+MODULE_LICENSE("GPL");
+
+
 Power Management
 ================
 
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7244c8be606..2e7530a4e7b 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -133,7 +133,7 @@ config I2C_PIIX4
 	    ATI IXP300
 	    ATI IXP400
 	    ATI SB600
-	    ATI SB700
+	    ATI SB700/SP5100
 	    ATI SB800
 	    AMD Hudson-2
 	    Serverworks OSB4
@@ -143,6 +143,10 @@ config I2C_PIIX4
 	    Serverworks HT-1100
 	    SMSC Victory66
 
+	  Some AMD chipsets contain two PIIX4-compatible SMBus
+	  controllers. This driver will attempt to use both controllers
+	  on the SB700/SP5100, if they have been initialized by the BIOS.
+
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-piix4.
 
diff --git a/drivers/i2c/busses/i2c-ali1535.c b/drivers/i2c/busses/i2c-ali1535.c
index e66d248fc12..125cd8e0ad2 100644
--- a/drivers/i2c/busses/i2c-ali1535.c
+++ b/drivers/i2c/busses/i2c-ali1535.c
@@ -531,15 +531,7 @@ static struct pci_driver ali1535_driver = {
 	.remove		= __devexit_p(ali1535_remove),
 };
 
-static int __init i2c_ali1535_init(void)
-{
-	return pci_register_driver(&ali1535_driver);
-}
-
-static void __exit i2c_ali1535_exit(void)
-{
-	pci_unregister_driver(&ali1535_driver);
-}
+module_pci_driver(ali1535_driver);
 
 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "
 	      "Philip Edelbrock <phil@netroedge.com>, "
@@ -547,6 +539,3 @@ MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "
 	      "and Dan Eaton <dan.eaton@rocketlogix.com>");
 MODULE_DESCRIPTION("ALI1535 SMBus driver");
 MODULE_LICENSE("GPL");
-
-module_init(i2c_ali1535_init);
-module_exit(i2c_ali1535_exit);
diff --git a/drivers/i2c/busses/i2c-ali1563.c b/drivers/i2c/busses/i2c-ali1563.c
index 47ae0091e02..e02d9f86c6a 100644
--- a/drivers/i2c/busses/i2c-ali1563.c
+++ b/drivers/i2c/busses/i2c-ali1563.c
@@ -431,18 +431,6 @@ static struct pci_driver ali1563_pci_driver = {
 	.remove		= __devexit_p(ali1563_remove),
 };
 
-static int __init ali1563_init(void)
-{
-	return pci_register_driver(&ali1563_pci_driver);
-}
-
-module_init(ali1563_init);
-
-static void __exit ali1563_exit(void)
-{
-	pci_unregister_driver(&ali1563_pci_driver);
-}
-
-module_exit(ali1563_exit);
+module_pci_driver(ali1563_pci_driver);
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/i2c/busses/i2c-ali15x3.c b/drivers/i2c/busses/i2c-ali15x3.c
index 087ea9caa74..ce8d26d053a 100644
--- a/drivers/i2c/busses/i2c-ali15x3.c
+++ b/drivers/i2c/busses/i2c-ali15x3.c
@@ -513,21 +513,10 @@ static struct pci_driver ali15x3_driver = {
 	.remove		= __devexit_p(ali15x3_remove),
 };
 
-static int __init i2c_ali15x3_init(void)
-{
-	return pci_register_driver(&ali15x3_driver);
-}
-
-static void __exit i2c_ali15x3_exit(void)
-{
-	pci_unregister_driver(&ali15x3_driver);
-}
+module_pci_driver(ali15x3_driver);
 
 MODULE_AUTHOR ("Frodo Looijaard <frodol@dds.nl>, "
 		"Philip Edelbrock <phil@netroedge.com>, "
 		"and Mark D. Studebaker <mdsxyz123@yahoo.com>");
 MODULE_DESCRIPTION("ALI15X3 SMBus driver");
 MODULE_LICENSE("GPL");
-
-module_init(i2c_ali15x3_init);
-module_exit(i2c_ali15x3_exit);
diff --git a/drivers/i2c/busses/i2c-amd756.c b/drivers/i2c/busses/i2c-amd756.c
index eb778bf15c1..304aa03b57b 100644
--- a/drivers/i2c/busses/i2c-amd756.c
+++ b/drivers/i2c/busses/i2c-amd756.c
@@ -410,21 +410,10 @@ static struct pci_driver amd756_driver = {
 	.remove		= __devexit_p(amd756_remove),
 };
 
-static int __init amd756_init(void)
-{
-	return pci_register_driver(&amd756_driver);
-}
-
-static void __exit amd756_exit(void)
-{
-	pci_unregister_driver(&amd756_driver);
-}
+module_pci_driver(amd756_driver);
 
 MODULE_AUTHOR("Merlin Hughes <merlin@merlin.org>");
 MODULE_DESCRIPTION("AMD756/766/768/8111 and nVidia nForce SMBus driver");
 MODULE_LICENSE("GPL");
 
 EXPORT_SYMBOL(amd756_smbus);
-
-module_init(amd756_init)
-module_exit(amd756_exit)
diff --git a/drivers/i2c/busses/i2c-amd8111.c b/drivers/i2c/busses/i2c-amd8111.c
index e5ac53b99b0..0919ac1d99a 100644
--- a/drivers/i2c/busses/i2c-amd8111.c
+++ b/drivers/i2c/busses/i2c-amd8111.c
@@ -491,15 +491,4 @@ static struct pci_driver amd8111_driver = {
 	.remove		= __devexit_p(amd8111_remove),
 };
 
-static int __init i2c_amd8111_init(void)
-{
-	return pci_register_driver(&amd8111_driver);
-}
-
-static void __exit i2c_amd8111_exit(void)
-{
-	pci_unregister_driver(&amd8111_driver);
-}
-
-module_init(i2c_amd8111_init);
-module_exit(i2c_amd8111_exit);
+module_pci_driver(amd8111_driver);
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index 00e8f213f56..92a1e2c15ba 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -374,17 +374,7 @@ static struct pci_driver dw_i2c_driver = {
 	},
 };
 
-static int __init dw_i2c_init_driver(void)
-{
-	return  pci_register_driver(&dw_i2c_driver);
-}
-module_init(dw_i2c_init_driver);
-
-static void __exit dw_i2c_exit_driver(void)
-{
-	pci_unregister_driver(&dw_i2c_driver);
-}
-module_exit(dw_i2c_exit_driver);
+module_pci_driver(dw_i2c_driver);
 
 MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
 MODULE_DESCRIPTION("Synopsys DesignWare PCI I2C bus adapter");
diff --git a/drivers/i2c/busses/i2c-diolan-u2c.c b/drivers/i2c/busses/i2c-diolan-u2c.c
index 7eb19a5222f..aedb94f34bf 100644
--- a/drivers/i2c/busses/i2c-diolan-u2c.c
+++ b/drivers/i2c/busses/i2c-diolan-u2c.c
@@ -517,6 +517,6 @@ static struct usb_driver diolan_u2c_driver = {
 
 module_usb_driver(diolan_u2c_driver);
 
-MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 MODULE_DESCRIPTION(DRIVER_NAME " driver");
 MODULE_LICENSE("GPL");
diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c
index 2f74ae872e1..259f7697bf2 100644
--- a/drivers/i2c/busses/i2c-eg20t.c
+++ b/drivers/i2c/busses/i2c-eg20t.c
@@ -953,17 +953,7 @@ static struct pci_driver pch_pcidriver = {
 	.resume = pch_i2c_resume
 };
 
-static int __init pch_pci_init(void)
-{
-	return pci_register_driver(&pch_pcidriver);
-}
-module_init(pch_pci_init);
-
-static void __exit pch_pci_exit(void)
-{
-	pci_unregister_driver(&pch_pcidriver);
-}
-module_exit(pch_pci_exit);
+module_pci_driver(pch_pcidriver);
 
 MODULE_DESCRIPTION("Intel EG20T PCH/LAPIS Semico ML7213/ML7223/ML7831 IOH I2C");
 MODULE_LICENSE("GPL");
diff --git a/drivers/i2c/busses/i2c-hydra.c b/drivers/i2c/busses/i2c-hydra.c
index c527de17db4..c9f95e1666a 100644
--- a/drivers/i2c/busses/i2c-hydra.c
+++ b/drivers/i2c/busses/i2c-hydra.c
@@ -156,23 +156,8 @@ static struct pci_driver hydra_driver = {
 	.remove		= __devexit_p(hydra_remove),
 };
 
-static int __init i2c_hydra_init(void)
-{
-	return pci_register_driver(&hydra_driver);
-}
-
-
-static void __exit i2c_hydra_exit(void)
-{
-	pci_unregister_driver(&hydra_driver);
-}
-
-
+module_pci_driver(hydra_driver);
 
 MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
 MODULE_DESCRIPTION("i2c for Apple Hydra Mac I/O");
 MODULE_LICENSE("GPL");
-
-module_init(i2c_hydra_init);
-module_exit(i2c_hydra_exit);
-
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index ae2945a5e00..898dcf9c7ad 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -60,10 +60,12 @@
   Block process call transaction   no
   I2C block read transaction       yes  (doesn't use the block buffer)
   Slave mode                       no
+  Interrupt processing             yes
 
   See the file Documentation/i2c/busses/i2c-i801 for details.
 */
 
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
@@ -76,6 +78,7 @@
 #include <linux/io.h>
 #include <linux/dmi.h>
 #include <linux/slab.h>
+#include <linux/wait.h>
 
 /* I801 SMBus address offsets */
 #define SMBHSTSTS(p)	(0 + (p)->smba)
@@ -91,8 +94,12 @@
 
 /* PCI Address Constants */
 #define SMBBAR		4
+#define SMBPCISTS	0x006
 #define SMBHSTCFG	0x040
 
+/* Host status bits for SMBPCISTS */
+#define SMBPCISTS_INTS		0x08
+
 /* Host configuration bits for SMBHSTCFG */
 #define SMBHSTCFG_HST_EN	1
 #define SMBHSTCFG_SMB_SMI_EN	2
@@ -102,12 +109,8 @@
 #define SMBAUXCTL_CRC		1
 #define SMBAUXCTL_E32B		2
 
-/* kill bit for SMBHSTCNT */
-#define SMBHSTCNT_KILL		2
-
 /* Other settings */
 #define MAX_RETRIES		400
-#define ENABLE_INT9		0	/* set to 0x01 to enable - untested */
 
 /* I801 command constants */
 #define I801_QUICK		0x00
@@ -117,10 +120,13 @@
 #define I801_PROC_CALL		0x10	/* unimplemented */
 #define I801_BLOCK_DATA		0x14
 #define I801_I2C_BLOCK_DATA	0x18	/* ICH5 and later */
-#define I801_BLOCK_LAST		0x34
-#define I801_I2C_BLOCK_LAST	0x38	/* ICH5 and later */
-#define I801_START		0x40
-#define I801_PEC_EN		0x80	/* ICH3 and later */
+
+/* I801 Host Control register bits */
+#define SMBHSTCNT_INTREN	0x01
+#define SMBHSTCNT_KILL		0x02
+#define SMBHSTCNT_LAST_BYTE	0x20
+#define SMBHSTCNT_START		0x40
+#define SMBHSTCNT_PEC_EN	0x80	/* ICH3 and later */
 
 /* I801 Hosts Status register bits */
 #define SMBHSTSTS_BYTE_DONE	0x80
@@ -132,9 +138,11 @@
 #define SMBHSTSTS_INTR		0x02
 #define SMBHSTSTS_HOST_BUSY	0x01
 
-#define STATUS_FLAGS		(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_FAILED | \
-				 SMBHSTSTS_BUS_ERR | SMBHSTSTS_DEV_ERR | \
-				 SMBHSTSTS_INTR)
+#define STATUS_ERROR_FLAGS	(SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
+				 SMBHSTSTS_DEV_ERR)
+
+#define STATUS_FLAGS		(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \
+				 STATUS_ERROR_FLAGS)
 
 /* Older devices have their ID defined in <linux/pci_ids.h> */
 #define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS	0x1c22
@@ -154,6 +162,17 @@ struct i801_priv {
 	unsigned char original_hstcfg;
 	struct pci_dev *pci_dev;
 	unsigned int features;
+
+	/* isr processing */
+	wait_queue_head_t waitq;
+	u8 status;
+
+	/* Command state used by isr for byte-by-byte block transactions */
+	u8 cmd;
+	bool is_read;
+	int count;
+	int len;
+	u8 *data;
 };
 
 static struct pci_driver i801_driver;
@@ -162,6 +181,7 @@ static struct pci_driver i801_driver;
 #define FEATURE_BLOCK_BUFFER	(1 << 1)
 #define FEATURE_BLOCK_PROC	(1 << 2)
 #define FEATURE_I2C_BLOCK_READ	(1 << 3)
+#define FEATURE_IRQ		(1 << 4)
 /* Not really a feature, but it's convenient to handle it as such */
 #define FEATURE_IDF		(1 << 15)
 
@@ -170,6 +190,7 @@ static const char *i801_feature_names[] = {
 	"Block buffer",
 	"Block process call",
 	"I2C block read",
+	"Interrupt",
 };
 
 static unsigned int disable_features;
@@ -205,13 +226,22 @@ static int i801_check_pre(struct i801_priv *priv)
 	return 0;
 }
 
-/* Convert the status register to an error code, and clear it. */
-static int i801_check_post(struct i801_priv *priv, int status, int timeout)
+/*
+ * Convert the status register to an error code, and clear it.
+ * Note that status only contains the bits we want to clear, not the
+ * actual register value.
+ */
+static int i801_check_post(struct i801_priv *priv, int status)
 {
 	int result = 0;
 
-	/* If the SMBus is still busy, we give up */
-	if (timeout) {
+	/*
+	 * If the SMBus is still busy, we give up
+	 * Note: This timeout condition only happens when using polling
+	 * transactions.  For interrupt operation, NAK/timeout is indicated by
+	 * DEV_ERR.
+	 */
+	if (unlikely(status < 0)) {
 		dev_err(&priv->pci_dev->dev, "Transaction timeout\n");
 		/* try to stop the current command */
 		dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n");
@@ -244,64 +274,76 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout)
 		dev_dbg(&priv->pci_dev->dev, "Lost arbitration\n");
 	}
 
-	if (result) {
-		/* Clear error flags */
-		outb_p(status & STATUS_FLAGS, SMBHSTSTS(priv));
-		status = inb_p(SMBHSTSTS(priv)) & STATUS_FLAGS;
-		if (status) {
-			dev_warn(&priv->pci_dev->dev, "Failed clearing status "
-				 "flags at end of transaction (%02x)\n",
-				 status);
-		}
-	}
+	/* Clear status flags except BYTE_DONE, to be cleared by caller */
+	outb_p(status, SMBHSTSTS(priv));
 
 	return result;
 }
 
-static int i801_transaction(struct i801_priv *priv, int xact)
+/* Wait for BUSY being cleared and either INTR or an error flag being set */
+static int i801_wait_intr(struct i801_priv *priv)
 {
-	int status;
-	int result;
 	int timeout = 0;
-
-	result = i801_check_pre(priv);
-	if (result < 0)
-		return result;
-
-	/* the current contents of SMBHSTCNT can be overwritten, since PEC,
-	 * INTREN, SMBSCMD are passed in xact */
-	outb_p(xact | I801_START, SMBHSTCNT(priv));
+	int status;
 
 	/* We will always wait for a fraction of a second! */
 	do {
 		usleep_range(250, 500);
 		status = inb_p(SMBHSTSTS(priv));
-	} while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES));
+	} while (((status & SMBHSTSTS_HOST_BUSY) ||
+		  !(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR))) &&
+		 (timeout++ < MAX_RETRIES));
 
-	result = i801_check_post(priv, status, timeout > MAX_RETRIES);
-	if (result < 0)
-		return result;
-
-	outb_p(SMBHSTSTS_INTR, SMBHSTSTS(priv));
-	return 0;
+	if (timeout > MAX_RETRIES) {
+		dev_dbg(&priv->pci_dev->dev, "INTR Timeout!\n");
+		return -ETIMEDOUT;
+	}
+	return status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR);
 }
 
-/* wait for INTR bit as advised by Intel */
-static void i801_wait_hwpec(struct i801_priv *priv)
+/* Wait for either BYTE_DONE or an error flag being set */
+static int i801_wait_byte_done(struct i801_priv *priv)
 {
 	int timeout = 0;
 	int status;
 
+	/* We will always wait for a fraction of a second! */
 	do {
 		usleep_range(250, 500);
 		status = inb_p(SMBHSTSTS(priv));
-	} while ((!(status & SMBHSTSTS_INTR))
-		 && (timeout++ < MAX_RETRIES));
+	} while (!(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_BYTE_DONE)) &&
+		 (timeout++ < MAX_RETRIES));
 
-	if (timeout > MAX_RETRIES)
-		dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n");
+	if (timeout > MAX_RETRIES) {
+		dev_dbg(&priv->pci_dev->dev, "BYTE_DONE Timeout!\n");
+		return -ETIMEDOUT;
+	}
+	return status & STATUS_ERROR_FLAGS;
+}
 
-	outb_p(status, SMBHSTSTS(priv));
+static int i801_transaction(struct i801_priv *priv, int xact)
+{
+	int status;
+	int result;
+
+	result = i801_check_pre(priv);
+	if (result < 0)
+		return result;
+
+	if (priv->features & FEATURE_IRQ) {
+		outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
+		       SMBHSTCNT(priv));
+		wait_event(priv->waitq, (status = priv->status));
+		priv->status = 0;
+		return i801_check_post(priv, status);
+	}
+
+	/* the current contents of SMBHSTCNT can be overwritten, since PEC,
+	 * SMBSCMD are passed in xact */
+	outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv));
+
+	status = i801_wait_intr(priv);
+	return i801_check_post(priv, status);
 }
 
 static int i801_block_transaction_by_block(struct i801_priv *priv,
@@ -321,8 +363,8 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,
 			outb_p(data->block[i+1], SMBBLKDAT(priv));
 	}
 
-	status = i801_transaction(priv, I801_BLOCK_DATA | ENABLE_INT9 |
-				  I801_PEC_EN * hwpec);
+	status = i801_transaction(priv, I801_BLOCK_DATA |
+				  (hwpec ? SMBHSTCNT_PEC_EN : 0));
 	if (status)
 		return status;
 
@@ -338,6 +380,98 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,
 	return 0;
 }
 
+static void i801_isr_byte_done(struct i801_priv *priv)
+{
+	if (priv->is_read) {
+		/* For SMBus block reads, length is received with first byte */
+		if (((priv->cmd & 0x1c) == I801_BLOCK_DATA) &&
+		    (priv->count == 0)) {
+			priv->len = inb_p(SMBHSTDAT0(priv));
+			if (priv->len < 1 || priv->len > I2C_SMBUS_BLOCK_MAX) {
+				dev_err(&priv->pci_dev->dev,
+					"Illegal SMBus block read size %d\n",
+					priv->len);
+				/* FIXME: Recover */
+				priv->len = I2C_SMBUS_BLOCK_MAX;
+			} else {
+				dev_dbg(&priv->pci_dev->dev,
+					"SMBus block read size is %d\n",
+					priv->len);
+			}
+			priv->data[-1] = priv->len;
+		}
+
+		/* Read next byte */
+		if (priv->count < priv->len)
+			priv->data[priv->count++] = inb(SMBBLKDAT(priv));
+		else
+			dev_dbg(&priv->pci_dev->dev,
+				"Discarding extra byte on block read\n");
+
+		/* Set LAST_BYTE for last byte of read transaction */
+		if (priv->count == priv->len - 1)
+			outb_p(priv->cmd | SMBHSTCNT_LAST_BYTE,
+			       SMBHSTCNT(priv));
+	} else if (priv->count < priv->len - 1) {
+		/* Write next byte, except for IRQ after last byte */
+		outb_p(priv->data[++priv->count], SMBBLKDAT(priv));
+	}
+
+	/* Clear BYTE_DONE to continue with next byte */
+	outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
+}
+
+/*
+ * There are two kinds of interrupts:
+ *
+ * 1) i801 signals transaction completion with one of these interrupts:
+ *      INTR - Success
+ *      DEV_ERR - Invalid command, NAK or communication timeout
+ *      BUS_ERR - SMI# transaction collision
+ *      FAILED - transaction was canceled due to a KILL request
+ *    When any of these occur, update ->status and wake up the waitq.
+ *    ->status must be cleared before kicking off the next transaction.
+ *
+ * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
+ *    occurs for each byte of a byte-by-byte to prepare the next byte.
+ */
+static irqreturn_t i801_isr(int irq, void *dev_id)
+{
+	struct i801_priv *priv = dev_id;
+	u16 pcists;
+	u8 status;
+
+	/* Confirm this is our interrupt */
+	pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists);
+	if (!(pcists & SMBPCISTS_INTS))
+		return IRQ_NONE;
+
+	status = inb_p(SMBHSTSTS(priv));
+	if (status != 0x42)
+		dev_dbg(&priv->pci_dev->dev, "irq: status = %02x\n", status);
+
+	if (status & SMBHSTSTS_BYTE_DONE)
+		i801_isr_byte_done(priv);
+
+	/*
+	 * Clear irq sources and report transaction result.
+	 * ->status must be cleared before the next transaction is started.
+	 */
+	status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS;
+	if (status) {
+		outb_p(status, SMBHSTSTS(priv));
+		priv->status |= status;
+		wake_up(&priv->waitq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * For "byte-by-byte" block transactions:
+ *   I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1
+ *   I2C read uses cmd=I801_I2C_BLOCK_DATA
+ */
 static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 					       union i2c_smbus_data *data,
 					       char read_write, int command,
@@ -347,7 +481,6 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 	int smbcmd;
 	int status;
 	int result;
-	int timeout;
 
 	result = i801_check_pre(priv);
 	if (result < 0)
@@ -360,36 +493,39 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 		outb_p(data->block[1], SMBBLKDAT(priv));
 	}
 
+	if (command == I2C_SMBUS_I2C_BLOCK_DATA &&
+	    read_write == I2C_SMBUS_READ)
+		smbcmd = I801_I2C_BLOCK_DATA;
+	else
+		smbcmd = I801_BLOCK_DATA;
+
+	if (priv->features & FEATURE_IRQ) {
+		priv->is_read = (read_write == I2C_SMBUS_READ);
+		if (len == 1 && priv->is_read)
+			smbcmd |= SMBHSTCNT_LAST_BYTE;
+		priv->cmd = smbcmd | SMBHSTCNT_INTREN;
+		priv->len = len;
+		priv->count = 0;
+		priv->data = &data->block[1];
+
+		outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
+		wait_event(priv->waitq, (status = priv->status));
+		priv->status = 0;
+		return i801_check_post(priv, status);
+	}
+
 	for (i = 1; i <= len; i++) {
-		if (i == len && read_write == I2C_SMBUS_READ) {
-			if (command == I2C_SMBUS_I2C_BLOCK_DATA)
-				smbcmd = I801_I2C_BLOCK_LAST;
-			else
-				smbcmd = I801_BLOCK_LAST;
-		} else {
-			if (command == I2C_SMBUS_I2C_BLOCK_DATA
-			 && read_write == I2C_SMBUS_READ)
-				smbcmd = I801_I2C_BLOCK_DATA;
-			else
-				smbcmd = I801_BLOCK_DATA;
-		}
-		outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT(priv));
+		if (i == len && read_write == I2C_SMBUS_READ)
+			smbcmd |= SMBHSTCNT_LAST_BYTE;
+		outb_p(smbcmd, SMBHSTCNT(priv));
 
 		if (i == 1)
-			outb_p(inb(SMBHSTCNT(priv)) | I801_START,
+			outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
 			       SMBHSTCNT(priv));
 
-		/* We will always wait for a fraction of a second! */
-		timeout = 0;
-		do {
-			usleep_range(250, 500);
-			status = inb_p(SMBHSTSTS(priv));
-		} while ((!(status & SMBHSTSTS_BYTE_DONE))
-			 && (timeout++ < MAX_RETRIES));
-
-		result = i801_check_post(priv, status, timeout > MAX_RETRIES);
-		if (result < 0)
-			return result;
+		status = i801_wait_byte_done(priv);
+		if (status)
+			goto exit;
 
 		if (i == 1 && read_write == I2C_SMBUS_READ
 		 && command != I2C_SMBUS_I2C_BLOCK_DATA) {
@@ -416,10 +552,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 			outb_p(data->block[i+1], SMBBLKDAT(priv));
 
 		/* signals SMBBLKDAT ready */
-		outb_p(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR, SMBHSTSTS(priv));
+		outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
 	}
 
-	return 0;
+	status = i801_wait_intr(priv);
+exit:
+	return i801_check_post(priv, status);
 }
 
 static int i801_set_block_buffer_mode(struct i801_priv *priv)
@@ -474,9 +612,6 @@ static int i801_block_transaction(struct i801_priv *priv,
 							     read_write,
 							     command, hwpec);
 
-	if (result == 0 && hwpec)
-		i801_wait_hwpec(priv);
-
 	if (command == I2C_SMBUS_I2C_BLOCK_DATA
 	 && read_write == I2C_SMBUS_WRITE) {
 		/* restore saved config