Re: [PATCH] OMAP: MMC: Move set_power to platform data

["Juha Yrjölä" <juha.yrjola@nokia.com>]

On Fri, Mar 03, 2006 at 05:24:21AM -0800, ext Komal Shah wrote:

>  #include "omap.h"
> @@ -102,6 +100,7 @@ struct mmc_omap_host {
>  	struct work_struct	switch_work;
>  	struct timer_list	switch_timer;
>  	int			switch_last_state;
> +	void (*set_power)(void __iomem *base, int on);
>  };

Note that just "on" is not enough; some power supplies have support for
setting the voltage to several different values.

> diff --git a/include/asm-arm/arch-omap/board.h b/include/asm-arm/arch-omap/board.h
> index 6d6240a..168662f 100644
> --- a/include/asm-arm/arch-omap/board.h
> +++ b/include/asm-arm/arch-omap/board.h
> @@ -46,6 +46,7 @@ struct omap_mmc_conf {
>  	s16 power_pin;
>  	s16 switch_pin;
>  	s16 wp_pin;
> +	void (*set_power)(void __iomem *base, int on);
>  };

You shouldn't use the struct in board.h for this.  It is meant for passing
data from the bootloader, and passing a kernel function pointer from the
bootloader is problematic, to say the least. =)

The proper way to solve this is to introde the concept of a voltage framework,
so that we can reference voltages by name instead of a function.

Cheers,
Juha