Re: [PATCH 3/4] HSMMC: Add support for the second controller

[David Brownell <david-b@pacbell.net>]

On Thursday 30 October 2008, Tony Lindgren wrote:
> * David Brownell <david-b@pacbell.net> [081030 20:12]:
> >
> > Related:  shouldn't hsmmc_init() accept a set of params, maybe even a struct,
> > describing how each controller is wired?
> > 
> > 	- which controller (1, 2, 3)
> > 	- how many data wires are used (1, 4, 8)
> > 	- supported voltages (mask)
> > 	- card detect gpio (or negative) ... assume gpio_to_irq(gpio) works
> > 	- write protect gpio (or negative)
> > 	- callback for updating the voltages
> > 
> > That would support more complete functionality ... and get away from
> > the current hard-wiring of most of those parameters.
> 
> Yeah I don't know what the right solution is.. I was thinking about
> passing the struct omap_mmc_platform_data to hsmmc_init, but then
> again hsmmc.c does not know anything about the custom configurations
> and the power functions. So right now hsmmc.c would only call
> omap2_init_mmc() with the custom struct omap_mmc_platform_data.

Part of it is that "hsmmc.c" is really twl4030-specific glue,
but it's misnamed as being more generic.

Glue to other kinds of interface should call omap2_init_mmc()
directly ... the issue here is that the twl-specific stuff isn't
quite generic enough yet.


> Maybe we should just let the boards with non-standarad wiring additionally
> initialize the other mmc controllers from board-*.c by calling
> omap2_init_mmc()?

How about this instead:  boards pass an __initdata struct in, not a
mask, and it's used to set up the current omap_mmc_platform_data.
Struct should handle common TWL wiring options; maybe:

	struct twl4030_hsmmc_info {
		u8	mmc;		/* controller 1/2/3 */
		u8	wires;		/* 1/4/8 wires */
		u8	twl_reg;	/* vmmc1/vmmc2 */
		bool	cd_debounce;	/* in case cd isn't on twl4030 */
		int	gpio_cd;	/* or -EINVAL */
		int	gpio_wp;	/* or -EINVAL */
	};

So for example Beagle would only set up MMC-1, 8-wires, VMMC1,
debounced TWL GPIO-0 for CD, and some OMAP GPIO for WP ... while
Overo would do the same with 4-wires and a different GPIO, then
call hsmmc_init() again with a second struct for MMC-2, 4-wires,
VMMC2, no CD, no WP.

That should be a simple tweak on top of what you've just sent,

- Dave