List:       linux-video
Subject:    [video4linux] I2C
From:       Mike Frisch <mfrisch () saturn ! tlug ! org>
Date:       1998-06-16 17:31:13


I am trying to write a driver for a Bt829 interfaced (through the I2C
'bus') to a BtV2115.  Are there any common I2C APIs or is each
manufacturer's implementation different (and implemented indepdently for
each driver in the kernel)?

Please go easy on me...  this is/will be my first driver.  I've got tech
docs and a reference card.  If anybody wants to help, I can get the cards
for around $50 USD (combination TV tuner/video card w/2MB VRAM).

Thanks.

Mike.

======================================================================
  Mike Frisch                         Email: mfrisch@saturn.tlug.org
  Northstar Technologies        WWW: http://saturn.tlug.org/~mfrisch
  Newmarket, Ontario, CANADA
======================================================================

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List:       linux-video
Subject:    Re: [video4linux] I2C
From:       Philip Blundell < Philip.Blundell () pobox ! com>
Date:       1998-06-16 17:49:17

>I am trying to write a driver for a Bt829 interfaced (through the I2C
>'bus') to a BtV2115.  Are there any common I2C APIs or is each
>manufacturer's implementation different (and implemented indepdently for
>each driver in the kernel)?

The I2C interface is pretty standard.  There's a generic I2C implementation in 
drivers/char/i2c.[ch].  You need to provide it with low-level functions to do 
bit banging and it provides you with read/write-byte functionality on top of 
this.

p.


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List:       linux-video
Subject:    Re: [video4linux] I2C
From:       Alan Cox < alan () cymru ! net>
Date:       1998-06-16 18:55:40

> 'bus') to a BtV2115.  Are there any common I2C APIs or is each
> manufacturer's implementation different (and implemented indepdently for
> each driver in the kernel)?
> 
> Please go easy on me...  this is/will be my first driver.  I've got tech
> docs and a reference card.  If anybody wants to help, I can get the cards
> for around $50 USD (combination TV tuner/video card w/2MB VRAM).

Gerd has an i2c layer (see drivers/char/i2c.c) you plug your card drivers
into that on one side (ie how do you send bits to the bus) and you write
chip drivers using that layer too - eg if your tuner is the same as one
of the BT848 tuners then insmod tuner.o will already have provided your
tuner. Similarly your BT829 driver can be an i2c driver and hopefully
once/if we ever get specs will also be usable for the ATI junk
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List:       linux-video
Subject:    Re: [video4linux] I2C
From:       Gerd Knorr <kraxel () goldbach ! isdn ! cs ! tu-berlin ! de>
Date:       1998-06-16 22:55:04

Alan Cox <alan@cymru.net> writes:

>> 'bus') to a BtV2115.  Are there any common I2C APIs or is each
>> manufacturer's implementation different (and implemented indepdently for
>> each driver in the kernel)?
>> 
>> Please go easy on me...  this is/will be my first driver.  I've got tech
>> docs and a reference card.  If anybody wants to help, I can get the cards
>> for around $50 USD (combination TV tuner/video card w/2MB VRAM).

>Gerd has an i2c layer (see drivers/char/i2c.c) you plug your card drivers
>into that on one side (ie how do you send bits to the bus) and you write
>chip drivers using that layer too - eg if your tuner is the same as one
>of the BT848 tuners then insmod tuner.o will already have provided your
>tuner. Similarly your BT829 driver can be an i2c driver and hopefully
>once/if we ever get specs will also be usable for the ATI junk

Just FYI:  I'm working with Simon Vogl (he wrote the i2c package which uses
major 89) on a i2c layer rewrite.

  Gerd

-- 
Gerd Knorr <kraxel@cs.tu-berlin.de>
Es muß in der Seele etwas geben, ähnlich den Jahresringen der Bäume.
				-- Gerhart Hauptmann
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List:       linux-video
Subject:    Re: [video4linux] I2C
From:       Alan Cox < alan () cymru ! net>
Date:       1998-06-17 11:46:51

> >Gerd has an i2c layer (see drivers/char/i2c.c) you plug your card drivers
> >into that on one side (ie how do you send bits to the bus) and you write
> >chip drivers using that layer too - eg if your tuner is the same as one
> >of the BT848 tuners then insmod tuner.o will already have provided your
> >tuner. Similarly your BT829 driver can be an i2c driver and hopefully
> >once/if we ever get specs will also be usable for the ATI junk
> 
> Just FYI:  I'm working with Simon Vogl (he wrote the i2c package which uses
> major 89) on a i2c layer rewrite.

Excellent. That will make it a lot nicer. Now we can have a drivers/i2c
for arbitary i2c weirdnesses (i2c thermometer and panel drivers anyone 8))
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List:       linux-video
Subject:    Re: [video4linux] I2C
From:       Gerd Knorr <kraxel () goldbach ! isdn ! cs ! tu-berlin ! de>
Date:       1998-06-18 14:09:04

On Wed, 17 Jun 1998, Alan Cox wrote:

> > Just FYI:  I'm working with Simon Vogl (he wrote the i2c package which uses
> > major 89) on a i2c layer rewrite.
> 
> Excellent. That will make it a lot nicer. Now we can have a drivers/i2c
> for arbitary i2c weirdnesses (i2c thermometer and panel drivers anyone 8))

xawtv-2.14 is out of the door, with a very first alpha version of the new
i2c code included (directory bttv/experimental).  So if someone wants to
have a look...

The tuner module is ported to the new i2c layer, msp3400 not yet.

  Gerd

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