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

Manu Abraham abraham.manu at gmail.com
Mon Aug 20 06:50:53 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.

It looks fine, althought one aspect i would like to mention:


       67 struct analog_parameters {
       68 	unsigned int frequency;
       69 	unsigned int mode;
       70 	unsigned int audmode;
       71 	__u64 std;
       72 };

       84 	int (*set_analog_params)(struct dvb_frontend *fe, struct
analog_parameters *p);

Rather than having the analog operations/data structures into
dvb_frontend (which is supposed to be purely digital for anyone reading
the code), you can move the operations/struct into the hybrid tuner
header (below) where the operations are really meant for.


       28 #include "dvb_frontend.h"

This would allow not to add in dvb_frontend header into the tuner header
unnecessarily as well.

The whole point being if we keep adding all stuff to dvb_frontend, in
the end it ends up with lot of stuff which aren't directly related.

Looks fine otherwise.

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