[linux-dvb] [RFC] Hybrid tuner refactoring, phase 1

Oliver Endriss o.endriss at gmx.de
Wed Aug 29 03:41:16 CEST 2007


Michael Krufky wrote:
> For the past few months, I've been working on refactoring the analog 
tuner.ko module, such that all hardware-specific code can be separated 
into dvb_frontend style tuner modules.
> 
> This allows for a single module to be used by both the v4l2 tuner 
interface via the tuner.ko i2c_client driver, and directly by the dvb 
subsystem's tuning system.
> 
> This refactoring process has zero impact to the way that v4l and dvb 
functions.
> 
> I have completed phase one of the refactoring process, and now it is 
ready for testing and review.
> 
> http://linuxtv.org/hg/~mkrufky/tuner-refactor-phase-1
> 
> A brief description of the individual changesets follows:
> 
> - tuner: kill i2c_client interface to tuner sub-drivers
> 
> This changeset removes the i2c_client interface between tuner.ko and 
the tuner sub-drivers.
> 
> The i2c_client interface to tuner.ko, itself, remains the same as it 
has been -- this is only an internal change that affects the 
interaction between tuner.ko and the hardware-specific code.
> 
> Some helper functions and macros were added in this changeset, in 
order to ease the conversion process, without causing headaches or 
breakage. (see tuner-i2c.c)  We can remove these extra structs and 
helper functions after the refactoring process is complete.
> 
> - hybrid tuner refactoring core changes, phase 1
> 
> This changeset contains the more interesting work, where tuner-core is 
altered to support attachment of dvb_frontend style tuner modules.  An 
additional method "set_analog_params" was added to struct 
dvb_tuner_ops, so as to avoid altering the DVB subsystem userspace API 
headers.  This change does not create any dependency of the DVB 
subsystem on V4L, nor does it create any dependency of the V4L 
subsystem on DVB.
> 
> - tda8290: convert from tuner sub-driver into dvb_frontend module
> - mt20xx: convert from tuner sub-driver into dvb_frontend module
> - tea5761: convert from tuner sub-driver into dvb_frontend module
> - tea5767: convert from tuner sub-driver into dvb_frontend module
> - tuner-simple: convert from tuner sub-driver into dvb_frontend module
> 
> These changesets handle the conversions of the individual tuner 
sub-drivers into dvb_frontend style tuner modules.
> 
> - tuner: alter Makefile to produce separate modules
> 
> This changeset makes the changes to the build system, required for 
building the tuner sub-drivers as separate modules, and the ability to 
deselect undesired tuner sub-drivers via Kconfig.
> 
> --------------------------------------------------
> 
> What comes next?
> 
> After phase 1 of hybrid tuner refactoring is merged into the master 
branch, there is no change to the behavior of the drivers, apart from 
the fact that users will now have the ability to deselect undesired 
tuner sub-drivers via Kconfig.
> 
> I have the following changes planned for hybrid tuner refactoring, 
phases 2, 3 and 4:
> 
> - analog if demodulator refactoring
> 
> In this step, an internal api for analog IF demods will be created, 
allowing us to refactor the tda9887 module, and also to handle tda8290 
separately from the tda8275 and tda8275a tuners.
> 
> - tda8290 refactoring
> 
> In addition to the analog if demodulator refactoring, duplicated code 
for the tda8275 and tda8275a tuners between tda8290.ko and tda827x.ko 
shall be consolidated.  In addition, support for the tda8295 and 
tda18271 devices will be added.
> 
> - tuner-simple refactoring
> 
> Tuner-simple will be cleaned up to take on more of an object-oriented 
approach, and duplicated code for certain tuners present in both 
tuner-simple and dvb-pll shall be consolidated.
> 
> - miscellaneous work and additional cleanups
> 
> mt20xx shall be cleaned up to properly handle tuning requests from the 
DVB subsystem, rather that going through tuner.ko -- this is a very 
small change, but I decided to wait on this until after phase 1 is 
merged into master.
> 
> Support for new hybrid tuner hardware will now be _much_ easier to 
develop and add into the v4l-dvb codebase.
> 
> --------------------------------------------------
> 
> I'd like to thank all of the people that have looked this over thus 
far, whom have given suggestions on how I can make this better and 
easier to review.
> 
> If there are any other questions, comments or concerns, I would love 
to hear them.  Please don't be shy -- feel free to let me know if you 
like or dislike this approach.  I'd like to have this merged as soon as 
possible, so that I may continue to work on the items mentioned about 
in the "What comes next?" section.
> 
> Now, it's time to go out and party!  I will be able to respond to any 
comments tomorrow afternoon.

While I currently don't have the time to completely review all 
changesets, the proposal looks fine to me.

The dvb_frontend extensions are ok.

Acked-by: Oliver Endriss <o.endriss at gmx.de>

CU
Oliver

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