[linux-dvb] [RFC] Hybrid tuner refactoring, phase 1
hverkuil at xs4all.nl
Sun Aug 19 23:38:13 CEST 2007
On Sunday 19 August 2007 00:25:40 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
> I have completed phase one of the refactoring process, and now it is
> ready for testing and review.
> 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
> 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.
I've reviewed your changes and it looks fine to me!
Acked-by: Hans Verkuil <hverkuil at xs4all.nl>
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