Re: WG: PCAN-USB: new socketCAN driver available

[Grosjean Stephane <s.grosjean@peak-system.com>]

Hi,

First of all, thank you for your time and all your comments.

Le 06/12/2011 22:24, Oliver Hartkopp a écrit :
 > On 06.12.2011 21:47, Sam Ravnborg wrote:
 >
 >> Today it is really recommended to do:
 >>
 >> obj-$(CONFIG_CAN_PEAK_USB) += peak_usb.o
 >> peak_usb-y := pcan_usb_core.o pcan_usb.o
 >>
 >> obj-$(CONFIG_CAN_PEAK_USB_PRO) += peak_usb_pro.o
 >> peak_usb_pro-y := pcan_usb_core.o pcan_usb_pro.o
 >>
 >> Both solutions will work - but the latter allows for some nice
 >> "kbuild" assignments to conditional stuff.
 >>

right...

 > I just tried out the suggestion myself ...
 >
 > As my idea was to link the common functions directly to the module 
binary this
 > may double the needed size. Maybe your approach is really better 8-)
 >
 > But the fact that the select should be omitted is still true.
 >
 > Better you define a
 >
 > config CAN_PEAK_USB
 >     tristate "PEAK System USB adapters"
 >
 > and then
 >
 > config CAN_PCAN_USB
 >     tristate "PEAK PCAN USB adapter"
 >     depends on CAN_PEAK_USB
 >
 >
 > config CAN_PCAN_USB_PRO
 >     tristate "PEAK PCAN USB Pro adapter"
 >     depends on CAN_PEAK_USB
 >
 > ...
 >
 > Regards,
 > Oliver

I thought this was better for memory size and also for easier handling 
of (any) further PEAK USB adapter, never know...
But, what next? According to your below Kconfig and Sam's Kbuild, and if 
I understand well your suggestions, the Kbuild file always builds 2 
module files, while I wanted to build only a single one, capable of 
handling one or both adapters.

Please, confirm that a mainline kernel driver should (must?) handle one 
and only one kind of device.
If it should (must), I will modify the Kbuild file as proposed by Sam, 
in order to build a peak_usb.ko and/or a peak_usb_pro.ko file.

But in that case, I wonder why the Kernel API offers some data 
structures like "struct usb_driver.id_table" which are supposed to 
describe more than one device id.

Regards,

Stéphane