[U-Boot] [PATCH 1/3] i2c: add i2c_core and prepare for new multibus support

[Tabi Timur-B04825]

On Tue, Jan 17, 2012 at 1:12 AM, Simon Glass <sjg at chromium.org> wrote:
> From: Heiko Schocher <hs at denx.de>
>
> This Patch introduce the new i2c_core file, which holds
> the I2C core functions, for the rework of the multibus/
> multiadapter support.
> Also adds changes in i2c.h for the new I2C multibus/multiadapter
> support. This new support can be activated with the
> CONFIG_SYS_I2C define.
>
> Signed-off-by: Heiko Schocher <hs at denx.de>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>  arch/arm/include/asm/global_data.h        |    3 +
>  arch/avr32/include/asm/global_data.h      |    3 +
>  arch/blackfin/include/asm/global_data.h   |    4 +-
>  arch/m68k/include/asm/global_data.h       |    3 +
>  arch/microblaze/include/asm/global_data.h |    3 +
>  arch/mips/include/asm/global_data.h       |    3 +
>  arch/nios2/include/asm/global_data.h      |    3 +
>  arch/powerpc/include/asm/global_data.h    |    3 +
>  arch/sh/include/asm/global_data.h         |    3 +
>  arch/sparc/include/asm/global_data.h      |    3 +
>  arch/x86/include/asm/global_data.h        |    3 +
>  drivers/i2c/Makefile                      |    1 +
>  drivers/i2c/i2c_core.c                    |  360 +++++++++++++++++++++++++++++
>  include/i2c.h                             |  199 +++++++++++++++-
>  14 files changed, 584 insertions(+), 10 deletions(-)
>  create mode 100644 drivers/i2c/i2c_core.c
>
> diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
> index 23a6077..924cea2 100644
> --- a/arch/arm/include/asm/global_data.h
> +++ b/arch/arm/include/asm/global_data.h
> @@ -87,6 +87,9 @@ typedef       struct  global_data {
>        unsigned long   post_log_res; /* success of POST test */
>        unsigned long   post_init_f_time; /* When post_init_f started */
>  #endif
> +#if defined(CONFIG_SYS_I2C)
> +       void            *cur_adap;      /* current used i2c adapter */
> +#endif

I was really hoping we could get rid of the concept of a "current" i2c
adapter, and just force all drivers to specify the I2C adapter they
want to use for a given I2C operation.  That's how Linux operates, and
it will prevent stuff like this:

void *old;
void *new;


old = get_current_i2c_adapter();
set_i2c_adapter(new);
// do I2C stuff
set_i2c_adapter(old);

-- 
Timur Tabi
Linux kernel developer at Freescale