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

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging: i2c-nforce2: Remove redundant error messages on ACPI conflict i2c: Use <linux/io.h> instead of <asm/io.h> i2c-algo-pca: Fix coding style issues i2c-dev: Fix all coding style issues i2c-core: Fix some coding style issues i2c-gpio: Move initialization code to subsys_initcall() i2c-parport: Make template structure const i2c-dev: Remove unnecessary casts at24: Fall back to byte or word reads if needed i2c-stub: Expose the default functionality flags i2c/scx200_acb: Make PCI device ids constant i2c-i801: Fix all checkpatch warnings i2c-i801: All newer devices have all the optional features i2c-i801: Let the user disable selected driver features
2010-05-21 10:49:43 -07:00 · 2010-05-21 10:49:43 -07:00 · e0bc5d4a54
parent 7f02ab3ce3 7c4fda1aa1
commit e0bc5d4a54
41 changed files with 216 additions and 166 deletions
--- a/Documentation/i2c/busses/i2c-i801
+++ b/Documentation/i2c/busses/i2c-i801
@ -27,7 +27,13 @@ Authors:
 Module Parameters
 -----------------

-None.
+* disable_features (bit vector)
+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


 Description
--- a/drivers/i2c/busses/i2c-ali1535.c
+++ b/drivers/i2c/busses/i2c-ali1535.c
@ -60,7 +60,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>


 /* ALI1535 SMBus address offsets */
--- a/drivers/i2c/busses/i2c-ali15x3.c
+++ b/drivers/i2c/busses/i2c-ali15x3.c
@ -67,7 +67,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 /* ALI15X3 SMBus address offsets */
 #define SMBHSTSTS	(0 + ali15x3_smba)
--- a/drivers/i2c/busses/i2c-amd756.c
+++ b/drivers/i2c/busses/i2c-amd756.c
@ -43,7 +43,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 /* AMD756 SMBus address offsets */
 #define SMB_ADDR_OFFSET		0xE0
--- a/drivers/i2c/busses/i2c-amd8111.c
+++ b/drivers/i2c/busses/i2c-amd8111.c
@ -18,7 +18,7 @@
 #include <linux/delay.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
-#include <asm/io.h>
+#include <linux/io.h>

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR ("Vojtech Pavlik <vojtech@suse.cz>");
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@ -23,8 +23,7 @@
 #include <linux/init.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
-
-#include <asm/io.h>
+#include <linux/io.h>

 #include <mach/at91_twi.h>
 #include <mach/board.h>
--- a/drivers/i2c/busses/i2c-elektor.c
+++ b/drivers/i2c/busses/i2c-elektor.c
@ -37,8 +37,8 @@
 #include <linux/isa.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-pcf.h>
+#include <linux/io.h>

-#include <asm/io.h>
 #include <asm/irq.h>

 #include "../algos/i2c-algo-pcf.h"
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@ -211,7 +211,7 @@ static int __init i2c_gpio_init(void)

 	return ret;
 }
-module_init(i2c_gpio_init);
+subsys_initcall(i2c_gpio_init);

 static void __exit i2c_gpio_exit(void)
 {
--- a/drivers/i2c/busses/i2c-hydra.c
+++ b/drivers/i2c/busses/i2c-hydra.c
@ -28,7 +28,7 @@
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
 #include <linux/init.h>
-#include <asm/io.h>
+#include <linux/io.h>
 #include <asm/hydra.h>


--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@ -138,6 +138,17 @@ static struct pci_dev *I801_dev;
 #define FEATURE_I2C_BLOCK_READ	(1 << 3)
 static unsigned int i801_features;

+static const char *i801_feature_names[] = {
+	"SMBus PEC",
+	"Block buffer",
+	"Block process call",
+	"I2C block read",
+};
+
+static unsigned int disable_features;
+module_param(disable_features, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(disable_features, "Disable selected driver features");
+
 /* Make sure the SMBus host is ready to start transmitting.
   Return 0 if it is, -EBUSY if it is not. */
 static int i801_check_pre(void)
@ -341,8 +352,7 @@ static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data,
 		do {
 			msleep(1);
 			status = inb_p(SMBHSTSTS);
-		}
-		while ((!(status & SMBHSTSTS_BYTE_DONE))
+		} while ((!(status & SMBHSTSTS_BYTE_DONE))
 			 && (timeout++ < MAX_TIMEOUT));

 		result = i801_check_post(status, timeout > MAX_TIMEOUT);
@ -689,10 +699,11 @@ static void __devinit dmi_check_onboard_devices(const struct dmi_header *dm,
 }
 #endif

-static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
+static int __devinit i801_probe(struct pci_dev *dev,
+				const struct pci_device_id *id)
 {
 	unsigned char temp;
-	int err;
+	int err, i;
 #if defined CONFIG_SENSORS_FSCHMD || defined CONFIG_SENSORS_FSCHMD_MODULE
 	const char *vendor;
 #endif
@ -700,26 +711,28 @@ static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id
 	I801_dev = dev;
 	i801_features = 0;
 	switch (dev->device) {
-	case PCI_DEVICE_ID_INTEL_82801EB_3:
-	case PCI_DEVICE_ID_INTEL_ESB_4:
-	case PCI_DEVICE_ID_INTEL_ICH6_16:
-	case PCI_DEVICE_ID_INTEL_ICH7_17:
-	case PCI_DEVICE_ID_INTEL_ESB2_17:
-	case PCI_DEVICE_ID_INTEL_ICH8_5:
-	case PCI_DEVICE_ID_INTEL_ICH9_6:
-	case PCI_DEVICE_ID_INTEL_TOLAPAI_1:
-	case PCI_DEVICE_ID_INTEL_ICH10_4:
-	case PCI_DEVICE_ID_INTEL_ICH10_5:
-	case PCI_DEVICE_ID_INTEL_PCH_SMBUS:
-	case PCI_DEVICE_ID_INTEL_CPT_SMBUS:
+	default:
 		i801_features |= FEATURE_I2C_BLOCK_READ;
 		/* fall through */
 	case PCI_DEVICE_ID_INTEL_82801DB_3:
 		i801_features |= FEATURE_SMBUS_PEC;
 		i801_features |= FEATURE_BLOCK_BUFFER;
+		/* fall through */
+	case PCI_DEVICE_ID_INTEL_82801CA_3:
+	case PCI_DEVICE_ID_INTEL_82801BA_2:
+	case PCI_DEVICE_ID_INTEL_82801AB_3:
+	case PCI_DEVICE_ID_INTEL_82801AA_3:
 		break;
 	}

+	/* Disable features on user request */
+	for (i = 0; i < ARRAY_SIZE(i801_feature_names); i++) {
+		if (i801_features & disable_features & (1 << i))
+			dev_notice(&dev->dev, "%s disabled by user\n",
+				   i801_feature_names[i]);
+	}
+	i801_features &= ~disable_features;
+
 	err = pci_enable_device(dev);
 	if (err) {
 		dev_err(&dev->dev, "Failed to enable SMBus PCI device (%d)\n",
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@ -39,7 +39,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <asm/irq.h>
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/i2c.h>
 #include <linux/i2c-id.h>
 #include <linux/of_platform.h>
--- a/drivers/i2c/busses/i2c-iop3xx.c
+++ b/drivers/i2c/busses/i2c-iop3xx.c
@ -38,8 +38,7 @@
 #include <linux/errno.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
-
-#include <asm/io.h>
+#include <linux/io.h>

 #include "i2c-iop3xx.h"

--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@ -17,8 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/mv643xx_i2c.h>
 #include <linux/platform_device.h>
-
-#include <asm/io.h>
+#include <linux/io.h>

 /* Register defines */
 #define	MV64XXX_I2C_REG_SLAVE_ADDR			0x00
--- a/drivers/i2c/busses/i2c-nforce2.c
+++ b/drivers/i2c/busses/i2c-nforce2.c
@ -57,7 +57,7 @@
 #include <linux/dmi.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
-#include <asm/io.h>
+#include <linux/io.h>

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR ("Hans-Frieder Vogt <hfvogt@gmx.net>");
@ -404,10 +404,9 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_

 	/* SMBus adapter 1 */
 	res1 = nforce2_probe_smb(dev, 4, NFORCE_PCI_SMB1, &smbuses[0], "SMB1");
-	if (res1 < 0) {
-		dev_err(&dev->dev, "Error probing SMB1.\n");
+	if (res1 < 0)
 		smbuses[0].base = 0;	/* to have a check value */
-	}
+
 	/* SMBus adapter 2 */
 	if (dmi_check_system(nforce2_dmi_blacklist2)) {
 		dev_err(&dev->dev, "Disabling SMB2 for safety reasons.\n");
@ -416,11 +415,10 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_
 	} else {
 		res2 = nforce2_probe_smb(dev, 5, NFORCE_PCI_SMB2, &smbuses[1],
 					 "SMB2");
-		if (res2 < 0) {
-			dev_err(&dev->dev, "Error probing SMB2.\n");
+		if (res2 < 0)
 			smbuses[1].base = 0;	/* to have a check value */
 	}
-	}
+
 	if ((res1 < 0) && (res2 < 0)) {
 		/* we did not find even one of the SMBuses, so we give up */
 		kfree(smbuses);
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@ -19,7 +19,7 @@
 #include <linux/wait.h>
 #include <linux/i2c-ocores.h>
 #include <linux/slab.h>
-#include <asm/io.h>
+#include <linux/io.h>

 struct ocores_i2c {
 	void __iomem *base;
--- a/drivers/i2c/busses/i2c-parport-light.c
+++ b/drivers/i2c/busses/i2c-parport-light.c
@ -33,7 +33,7 @@
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
 #include <linux/i2c-smbus.h>
-#include <asm/io.h>
+#include <linux/io.h>
 #include "i2c-parport.h"

 #define DEFAULT_BASE 0x378
--- a/drivers/i2c/busses/i2c-parport.c
+++ b/drivers/i2c/busses/i2c-parport.c
@ -137,7 +137,7 @@ static int parport_getsda(void *data)
   copied. The attaching code will set getscl to NULL for adapters that
   cannot read SCL back, and will also make the data field point to
   the parallel port structure. */
-static struct i2c_algo_bit_data parport_algo_data = {
+static const struct i2c_algo_bit_data parport_algo_data = {
 	.setsda		= parport_setsda,
 	.setscl		= parport_setscl,
 	.getsda		= parport_getsda,
--- a/drivers/i2c/busses/i2c-pasemi.c
+++ b/drivers/i2c/busses/i2c-pasemi.c
@ -25,7 +25,7 @@
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <asm/io.h>
+#include <linux/io.h>

 static struct pci_driver pasemi_smb_driver;

--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@ -30,8 +30,8 @@
 #include <linux/isa.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-pca.h>
+#include <linux/io.h>

-#include <asm/io.h>
 #include <asm/irq.h>

 #define DRIVER "i2c-pca-isa"
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@ -23,9 +23,9 @@
 #include <linux/i2c-algo-pca.h>
 #include <linux/i2c-pca-platform.h>
 #include <linux/gpio.h>
+#include <linux/io.h>

 #include <asm/irq.h>
-#include <asm/io.h>

 struct i2c_pca_pf_data {
 	void __iomem			*reg_base;
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@ -39,7 +39,7 @@
 #include <linux/init.h>
 #include <linux/dmi.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>


 /* PIIX4 SMBus address offsets */
--- a/drivers/i2c/busses/i2c-pmcmsp.c
+++ b/drivers/i2c/busses/i2c-pmcmsp.c
@ -33,7 +33,7 @@
 #include <linux/completion.h>
 #include <linux/mutex.h>
 #include <linux/delay.h>
-#include <asm/io.h>
+#include <linux/io.h>

 #define DRV_NAME	"pmcmsptwi"

--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@ -34,9 +34,9 @@
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
+#include <linux/io.h>

 #include <asm/irq.h>
-#include <asm/io.h>
 #include <plat/i2c.h>

 /*
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@ -35,9 +35,9 @@
 #include <linux/clk.h>
 #include <linux/cpufreq.h>
 #include <linux/slab.h>
+#include <linux/io.h>

 #include <asm/irq.h>
-#include <asm/io.h>

 #include <plat/regs-iic.h>
 #include <plat/iic.h>
--- a/drivers/i2c/busses/i2c-s6000.c
+++ b/drivers/i2c/busses/i2c-s6000.c
@ -36,8 +36,8 @@
 #include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
+#include <linux/io.h>

-#include <asm/io.h>
 #include "i2c-s6000.h"

 #define DRV_NAME "i2c-s6000"
--- a/drivers/i2c/busses/i2c-sh7760.c
+++ b/drivers/i2c/busses/i2c-sh7760.c
@ -16,10 +16,10 @@
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/io.h>

 #include <asm/clock.h>
 #include <asm/i2c-sh7760.h>
-#include <asm/io.h>

 /* register offsets */
 #define I2CSCR		0x0		/* slave ctrl		*/
--- a/drivers/i2c/busses/i2c-sibyte.c
+++ b/drivers/i2c/busses/i2c-sibyte.c
@ -22,7 +22,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
-#include <asm/io.h>
+#include <linux/io.h>
 #include <asm/sibyte/sb1250_regs.h>
 #include <asm/sibyte/sb1250_smbus.h>

--- a/drivers/i2c/busses/i2c-simtec.c
+++ b/drivers/i2c/busses/i2c-simtec.c
@ -24,12 +24,11 @@
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/io.h>

 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>

-#include <asm/io.h>
-
 struct simtec_i2c_data {
 	struct resource		*ioarea;
 	void __iomem		*reg;
--- a/drivers/i2c/busses/i2c-sis5595.c
+++ b/drivers/i2c/busses/i2c-sis5595.c
@ -61,7 +61,7 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 static int blacklist[] = {
 	PCI_DEVICE_ID_SI_540,
--- a/drivers/i2c/busses/i2c-sis630.c
+++ b/drivers/i2c/busses/i2c-sis630.c
@ -53,7 +53,7 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 /* SIS630 SMBus registers */
 #define SMB_STS			0x80	/* status */
--- a/drivers/i2c/busses/i2c-sis96x.c
+++ b/drivers/i2c/busses/i2c-sis96x.c
@ -38,7 +38,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 /* base address register in PCI config space */
 #define SIS96x_BAR 0x04
--- a/drivers/i2c/busses/i2c-stub.c
+++ b/drivers/i2c/busses/i2c-stub.c
@ -29,13 +29,16 @@
 #include <linux/i2c.h>

 #define MAX_CHIPS 10
+#define STUB_FUNC (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
+		   I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
+		   I2C_FUNC_SMBUS_I2C_BLOCK)

 static unsigned short chip_addr[MAX_CHIPS];
 module_param_array(chip_addr, ushort, NULL, S_IRUGO);
 MODULE_PARM_DESC(chip_addr,
 		 "Chip addresses (up to 10, between 0x03 and 0x77)");

-static unsigned long functionality = ~0UL;
+static unsigned long functionality = STUB_FUNC;
 module_param(functionality, ulong, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(functionality, "Override functionality bitfield");

@ -156,9 +159,7 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,

 static u32 stub_func(struct i2c_adapter *adapter)
 {
-	return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
-		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
-		I2C_FUNC_SMBUS_I2C_BLOCK) & functionality;
+	return STUB_FUNC & functionality;
 }

 static const struct i2c_algorithm smbus_algorithm = {
--- a/drivers/i2c/busses/i2c-versatile.c
+++ b/drivers/i2c/busses/i2c-versatile.c
@ -15,8 +15,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
-
-#include <asm/io.h>
+#include <linux/io.h>

 #define I2C_CONTROL	0x00
 #define I2C_CONTROLS	0x00
--- a/drivers/i2c/busses/i2c-via.c
+++ b/drivers/i2c/busses/i2c-via.c
@ -25,7 +25,7 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
-#include <asm/io.h>
+#include <linux/io.h>

 /* Power management registers */
 #define PM_CFG_REVID	0x08	/* silicon revision code */
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@ -51,7 +51,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
-#include <asm/io.h>
+#include <linux/io.h>

 static struct pci_dev *vt596_pdev;

--- a/drivers/i2c/busses/scx200_acb.c
+++ b/drivers/i2c/busses/scx200_acb.c
@ -32,7 +32,7 @@
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
-#include <asm/io.h>
+#include <linux/io.h>

 #include <linux/scx200.h>

@ -552,7 +552,7 @@ static int __init scx200_create_isa(const char *text, unsigned long base,
 * the name and the BAR where the I/O address resource is located.  ISA
 * devices are flagged with a bar value of -1 */

-static struct pci_device_id scx200_pci[] = {
+static const struct pci_device_id scx200_pci[] __initconst = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE),
 	  .driver_data = 0 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE),
--- a/drivers/i2c/busses/scx200_i2c.c
+++ b/drivers/i2c/busses/scx200_i2c.c
@ -27,7 +27,7 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
-#include <asm/io.h>
+#include <linux/io.h>

 #include <linux/scx200_gpio.h>

--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@ -35,7 +35,7 @@
 #include <linux/i2c.h>
 #include <linux/i2c-dev.h>
 #include <linux/jiffies.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>

 static struct i2c_driver i2cdev_driver;

@ -138,7 +138,7 @@ static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 	char *tmp;
 	int ret;

-	struct i2c_client *client = (struct i2c_client *)file->private_data;
+	struct i2c_client *client = file->private_data;

 	if (count > 8192)
 		count = 8192;
@ -157,12 +157,12 @@ static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 	return ret;
 }

-static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
-                             loff_t *offset)
+static ssize_t i2cdev_write(struct file *file, const char __user *buf,
+		size_t count, loff_t *offset)
 {
 	int ret;
 	char *tmp;
-	struct i2c_client *client = (struct i2c_client *)file->private_data;
+	struct i2c_client *client = file->private_data;

 	if (count > 8192)
 		count = 8192;
@ -369,7 +369,7 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,

 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	struct i2c_client *client = (struct i2c_client *)file->private_data;
+	struct i2c_client *client = file->private_data;
 	unsigned long funcs;

 	dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@ -54,7 +54,7 @@
 struct at24_data {
 	struct at24_platform_data chip;
 	struct memory_accessor macc;
-	bool use_smbus;
+	int use_smbus;

 	/*
 	 * Lock protects against activities from other Linux tasks,
@ -184,11 +184,19 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	if (count > io_limit)
 		count = io_limit;

-	if (at24->use_smbus) {
+	switch (at24->use_smbus) {
+	case I2C_SMBUS_I2C_BLOCK_DATA:
 		/* Smaller eeproms can work given some SMBus extension calls */
 		if (count > I2C_SMBUS_BLOCK_MAX)
 			count = I2C_SMBUS_BLOCK_MAX;
-	} else {
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		count = 2;
+		break;
+	case I2C_SMBUS_BYTE_DATA:
+		count = 1;
+		break;
+	default:
 		/*
 		 * When we have a better choice than SMBus calls, use a
 		 * combined I2C message. Write address; then read up to
@ -219,10 +227,27 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	timeout = jiffies + msecs_to_jiffies(write_timeout);
 	do {
 		read_time = jiffies;
-		if (at24->use_smbus) {
+		switch (at24->use_smbus) {
+		case I2C_SMBUS_I2C_BLOCK_DATA:
 			status = i2c_smbus_read_i2c_block_data(client, offset,
 					count, buf);
-		} else {
+			break;
+		case I2C_SMBUS_WORD_DATA:
+			status = i2c_smbus_read_word_data(client, offset);
+			if (status >= 0) {
+				buf[0] = status & 0xff;
+				buf[1] = status >> 8;
+				status = count;
+			}
+			break;
+		case I2C_SMBUS_BYTE_DATA:
+			status = i2c_smbus_read_byte_data(client, offset);
+			if (status >= 0) {
+				buf[0] = status;
+				status = count;
+			}
+			break;
+		default:
 			status = i2c_transfer(client->adapter, msg, 2);
 			if (status == 2)
 				status = count;
@ -436,7 +461,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct at24_platform_data chip;
 	bool writable;
-	bool use_smbus = false;
+	int use_smbus = 0;
 	struct at24_data *at24;
 	int err;
 	unsigned i, num_addresses;
@ -477,12 +502,19 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 			err = -EPFNOSUPPORT;
 			goto err_out;
 		}
-		if (!i2c_check_functionality(client->adapter,
+		if (i2c_check_functionality(client->adapter,
 				I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+			use_smbus = I2C_SMBUS_I2C_BLOCK_DATA;
+		} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_READ_WORD_DATA)) {
+			use_smbus = I2C_SMBUS_WORD_DATA;
+		} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+			use_smbus = I2C_SMBUS_BYTE_DATA;
+		} else {
 			err = -EPFNOSUPPORT;
 			goto err_out;
 		}
-		use_smbus = true;
 	}

 	if (chip.flags & AT24_FLAG_TAKE8ADDR)
@ -568,11 +600,16 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
 		at24->bin.size, client->name,
 		writable ? "(writable)" : "(read-only)");
+	if (use_smbus == I2C_SMBUS_WORD_DATA ||
+	    use_smbus == I2C_SMBUS_BYTE_DATA) {
+		dev_notice(&client->dev, "Falling back to %s reads, "
+			   "performance will suffer\n", use_smbus ==
+			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
+	}
 	dev_dbg(&client->dev,
-		"page_size %d, num_addresses %d, write_max %d%s\n",
+		"page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
 		chip.page_size, num_addresses,
-		at24->write_max,
-		use_smbus ? ", use_smbus" : "");
+		at24->write_max, use_smbus);

 	/* export data to kernel code */
 	if (chip.setup)