[linux-dvb] Re: no pwm entry in sysfs

[Johannes Stezenbach <js@linuxtv.org>]

Holger Waechtler wrote:
> Heikki Manninen wrote:
> >So, wrong answer to my question: How should I be able to have the pwm
> >entries for Fujitsu-Siemens DVB-C cards in sysfs?
> >
> >If there is no such way anymore, please let us know.
> 
> As far I remember from the discussion on the linux-dvb mailing list this 
> has been removed in the overhauling process because it unecessairily 
> complicated the code and the proper solution is trivial to implement -- 
> workarounds for broken EEPROMs that are easy to fix in userspace really 
> don't belong in kernelspace.

I don't remember such a discussion.

My guess is that it was removed because frontend drivers aren't
i2c_clients anymore, so there is no sysfs directory for them.
(There is a sysfs dir for the module, but not for the driver
instantiation, which there would be more than one of if you have
more than one card with that frontend.)

Two possible solutions:
- Add pwm sysfs attr to dvb-ttpci driver.
- Add array with fixed number of pwm values (for card 0..N)
  as a module parameter to ves1820 (will be in sysfs automatically).

The first one doesn't actually work because the pwm value is only
passed to ves1820.c at initialization, later pwm changes are useless.

Actually I'm not sure how arrays are represented in sysfs (if at all),
otherwise the 2nd solution would be fairly simple. (The first solution
could use the code from ves1820.c rev1.50, the second from rev1.43.)

Patches welcome.

Johannes