v4l: saa7134 module

["Markus Rechberger" <mrechberger (at) gmail.com>]

Hi Hartmut,

On 2/6/07, Hartmut Hackmann <hartmut.hackmann (at) t-online.de> wrote:
> Hi, Markus
>
> Markus Rechberger schrieb:
> > History (Gerd Knorr: [patch] v4l: saa7134 module):
> > http://lkml.org/lkml/2005/1/20/93
> >
> > There seems to be a general issue with loading submodules within a core
> > module.
> > It won't work until the core module exports its symbols.
> > If sys_init_module would trigger a MODULE_STATE_LIVE at the end of
> > loading the module modprobe would deadlock with holding a file lock on
> > the core module.
> > Attached approach tries to load the module asynchronosly with help of a
> > workqueue.
> >
> > http://linuxtv.org/hg/~mrechberger/v4l-dvb-saa7134
> >
> > Markus
> >
> <snip>
> >
> Should i integrate your changes or will you ask Mauro to pull these?

Mauro should pull it as soon as someone Acked the patch.

> Also: I sent you a mail some days ago, maybe to the wrong address.
> Do you have any comments?

must have missed that mail..

> I will insert it here:
>
>
>  Michael pointed me to to a repository of yours were you defined a GPIO
> callback for the tuner module.
> Looks like i did something very similar: Access the GPIOs of the SAA713x
> in the tuner driver. the code is in
> http://linuxtv.org/hg/~hhackmann/v4l-dvb
>
> In the tuner struct, i declared a pointer to a function with the following
> prototype:
>
>    void (*tuner_gpio_func_t) (void *dev, int bit_no, int value)
>
> The parameters are:
>   void *dev : a pointer to the central device struct of the host
>               (saa713x, cx88 in your case.
>               this already is available in the i2c_client
> ->adapter->algo_data
>   int bit_no : the GPIO bit number to change
>   int value  : how to set the port. currently i defined
>                0 : static 0
>                1 : static 1
>                3 : tristate (just by accident)
>                4 and 5: vsync on GPIO 22. This is a special case for the
> tda8290
>
> My current code assigns this pointer through as extended tuner_setup struct
> via the TUNER_SET_TYPE_ADDR client call (together with an additional int.

I use the similar approach to fully switch the device to another mode,
not only to set up one gpio address.

int  (*gpio_write)(enum v4l2_tuner_type type, void *gpio_priv, int ptr);
enum v4l2_tuner_type type : apropriate video input (DVB/analogue TV)
void *gpio_priv                   : a pointer for a private data
structure (the same as your void *dev)
int ptr                                   : badly named, but it's an
identifier for doing different things currently values 0 and 1 are for
firmware uploads, it's like an ioctl command.
                                              value 2 is for
reinitializing the dvb demod.

There are several gpio writes performed within 1 callback already
(mostly toggling a GPIO bit)
I'd say my approach is more flexible than your one, though we could
make it more generic probably by using (void *dev, int command, void
*arg)?

> I had a glance at your code in
> http://linuxtv.org/hg/~mrechberger/v4l-dvb-kernel
> Your parameters are different, but the rest is similar. Can you please
> explain a bit more what your parameters are good for?
> It would be nice to find a common version of this.

done :)

cheers,
Markus

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