i2c-tiny-usb: Fix on big-endian systems

The functionality bit vector is always returned as a little-endian
32-bit number by the device, so it must be byte-swapped to the host
endianness.

On the other hand, the delay value is handled by the USB stack, so no
byte swapping is needed on our side.

This fixes bug #15105:
http://bugzilla.kernel.org/show_bug.cgi?id=15105

Reported-by: Jens Richter <jens@richter-stutensee.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Jens Richter <jens@richter-stutensee.de>
Cc: Till Harbaum <till@harbaum.org>
Cc: stable@kernel.org

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c
index b1c050ff311d..e29b6d5ba8ef 100644
--- a/drivers/i2c/busses/i2c-tiny-usb.c
+++ b/drivers/i2c/busses/i2c-tiny-usb.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/types.h>
 
 /* include interfaces to usb layer */
 #include <linux/usb.h>
@@ -31,8 +32,8 @@
 #define CMD_I2C_IO_END          (1<<1)
 
 /* i2c bit delay, default is 10us -> 100kHz */
-static int delay = 10;
-module_param(delay, int, 0);
+static unsigned short delay = 10;
+module_param(delay, ushort, 0);
 MODULE_PARM_DESC(delay, "bit delay in microseconds, "
                  "e.g. 10 for 100kHz (default is 100kHz)");
 
@@ -109,7 +110,7 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 
 static u32 usb_func(struct i2c_adapter *adapter)
 {
-        u32 func;
+        __le32 func;
 
         /* get functionality from adapter */
         if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
@@ -118,7 +119,7 @@ static u32 usb_func(struct i2c_adapter *adapter)
                 return 0;
         }
 
-        return func;
+        return le32_to_cpu(func);
 }
 
 /* This is the actual algorithm we define */
@@ -216,8 +217,7 @@ static int i2c_tiny_usb_probe(struct usb_interface *interface,
                  "i2c-tiny-usb at bus %03d device %03d",
                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 
-        if (usb_write(&dev->adapter, CMD_SET_DELAY,
-                      cpu_to_le16(delay), 0, NULL, 0) != 0) {
+        if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
                 dev_err(&dev->adapter.dev,
                         "failure setting delay to %dus\n", delay);
                 retval = -EIO;