[PATCH] i2c-parport: Make type parameter mandatory

This patch forces the user to specify what type of adapter is present when
loading i2c-parport or i2c-parport-light.  If none is specified, the driver
init simply fails - instead of assuming adapter type 0.

This alleviates the sometimes lengthy boot time delays which can be caused
by accidentally building one of these into a kernel along with several i2c
slave drivers that have lengthy probe routines (e.g. hwmon drivers).

Kconfig and documentation updated accordingly.

Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 19 insertions, 6 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 089c6f5b24de..d6d44946a283 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -286,7 +286,10 @@ config I2C_PARPORT
           This driver is a replacement for (and was inspired by) an older
           driver named i2c-philips-par.  The new driver supports more devices,
           and makes it easier to add support for new devices.
-          
+
+          An adapter type parameter is now mandatory.  Please read the file
+          Documentation/i2c/busses/i2c-parport for details.
+
           Another driver exists, named i2c-parport-light, which doesn't depend
           on the parport driver.  This is meant for embedded systems. Don't say
           Y here if you intend to say Y or M there.
diff --git a/drivers/i2c/busses/i2c-parport-light.c b/drivers/i2c/busses/i2c-parport-light.c
index c63025a4c861..e09ebbb2f9f0 100644
--- a/drivers/i2c/busses/i2c-parport-light.c
+++ b/drivers/i2c/busses/i2c-parport-light.c
@@ -121,9 +121,14 @@ static struct i2c_adapter parport_adapter = {
 
 static int __init i2c_parport_init(void)
 {
-        if (type < 0 || type >= ARRAY_SIZE(adapter_parm)) {
+        if (type < 0) {
+                printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
+                return -ENODEV;
+        }
+
+        if (type >= ARRAY_SIZE(adapter_parm)) {
                 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
-                type = 0;
+                return -ENODEV;
         }
 
         if (base == 0) {
diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c
index 7e2e8cd1c14a..934bd55bae15 100644
--- a/drivers/i2c/busses/i2c-parport.c
+++ b/drivers/i2c/busses/i2c-parport.c
@@ -241,9 +241,14 @@ static struct parport_driver i2c_parport_driver = {
 
 static int __init i2c_parport_init(void)
 {
-        if (type < 0 || type >= ARRAY_SIZE(adapter_parm)) {
+        if (type < 0) {
+                printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
+                return -ENODEV;
+        }
+
+        if (type >= ARRAY_SIZE(adapter_parm)) {
                 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
-                type = 0;
+                return -ENODEV;
         }
 
         return parport_register_driver(&i2c_parport_driver);
diff --git a/drivers/i2c/busses/i2c-parport.h b/drivers/i2c/busses/i2c-parport.h
index d702e5e0388d..9ddd816d5d0f 100644
--- a/drivers/i2c/busses/i2c-parport.h
+++ b/drivers/i2c/busses/i2c-parport.h
@@ -90,7 +90,7 @@ static struct adapter_parm adapter_parm[] = {
         },
 };
 
-static int type;
+static int type = -1;
 module_param(type, int, 0);
 MODULE_PARM_DESC(type,
         "Type of adapter:\n"