Re: [PATCH] usbnet: ipheth: Simplify device detection

[Guenter Roeck <linux@xxxxxxxxxxxx>]

On 4/26/19 4:27 AM, Simon Horman wrote:
> On Wed, Apr 24, 2019 at 10:58:24AM -0700, Guenter Roeck wrote:
> > All Apple products use the same protocol for tethering over USB.
> > To simplify the code and make it future proof, use
> > USB_VENDOR_AND_INTERFACE_INFO() instead of
> > USB_DEVICE_AND_INTERFACE_INFO() to automatically detect and support
> > all existing and future Apple products using the same interface.
>
> What if future Apple products behave differently?

Sure, Apple may decide to use the same device/class/subclass/protocol
identifier for a different protocol. That is unlikely but possible.

If the associated risk is considered higher than the benefit of supporting
new devices announcing the same protocol with a different product id,
please feel free to ignore (or nack) this patch.

Thanks,
Guenter

> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> > Tested with various iPads and iPhones up to X. iPhone 6 and later
> > up to and including X all use product ID 0x12a8, so this patch is
> > not strictly required, but it does simplify the code.
> >
> >   drivers/net/usb/ipheth.c | 58 +++---------------------------------------------
> >   1 file changed, 3 insertions(+), 55 deletions(-)
> >
> > diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
> > index 3d8a70d3ea9b..a01a71a7e48d 100644
> > --- a/drivers/net/usb/ipheth.c
> > +++ b/drivers/net/usb/ipheth.c
> > @@ -54,17 +54,6 @@
> >   #include <linux/workqueue.h>
> >   
> >   #define USB_VENDOR_APPLE        0x05ac
> > -#define USB_PRODUCT_IPHONE      0x1290
> > -#define USB_PRODUCT_IPHONE_3G   0x1292
> > -#define USB_PRODUCT_IPHONE_3GS  0x1294
> > -#define USB_PRODUCT_IPHONE_4	0x1297
> > -#define USB_PRODUCT_IPAD 0x129a
> > -#define USB_PRODUCT_IPAD_2	0x12a2
> > -#define USB_PRODUCT_IPAD_3	0x12a6
> > -#define USB_PRODUCT_IPAD_MINI    0x12ab
> > -#define USB_PRODUCT_IPHONE_4_VZW 0x129c
> > -#define USB_PRODUCT_IPHONE_4S	0x12a0
> > -#define USB_PRODUCT_IPHONE_5	0x12a8
> >   
> >   #define IPHETH_USBINTF_CLASS    255
> >   #define IPHETH_USBINTF_SUBCLASS 253
> > @@ -88,50 +77,9 @@
> >   #define IPHETH_CARRIER_ON       0x04
> >   
> >   static const struct usb_device_id ipheth_table[] = {
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_3G,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_3GS,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPAD,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPAD_2,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPAD_3,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPAD_MINI,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4_VZW,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_4S,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > -	{ USB_DEVICE_AND_INTERFACE_INFO(
> > -		USB_VENDOR_APPLE, USB_PRODUCT_IPHONE_5,
> > -		IPHETH_USBINTF_CLASS, IPHETH_USBINTF_SUBCLASS,
> > -		IPHETH_USBINTF_PROTO) },
> > +	{ USB_VENDOR_AND_INTERFACE_INFO(USB_VENDOR_APPLE, IPHETH_USBINTF_CLASS,
> > +					IPHETH_USBINTF_SUBCLASS,
> > +					IPHETH_USBINTF_PROTO) },
> >   	{ }
> >   };
> >   MODULE_DEVICE_TABLE(usb, ipheth_table);
> > --
> > 2.7.4