Re: [PATCH 11/15] wireless: wl1271: introduce platform device support

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On 07/06/2010 03:53 PM, ext Ohad Ben-Cohen wrote:
Hi Roger,

On Tue, Jul 6, 2010 at 1:35 PM, Roger Quadros<roger.quadros@xxxxxxxxx>  wrote:
My point is that shouldn't this be handled by SDIO core?

Care to explain what you mean / give a code example ?

If the Power enable GPIO can be treated as SDIO slot supply (i.e. vmmc), then the SDIO/MMC core should tackle it, just like it deals with supply for slots with removable cards.

see mmc_regulator_set_ocr()
mmc_power_up()
mmc_set_ios()

in drivers/mmc/core/core.c

and omap_hsmmc_set_ios()

in drivers/mmc/host/omap_hsmmc.c


If there are no users for the SDIO function and the card, doesn't the SDIO
core power down the slot and take care of re-initialization when it is
powered up?

You need card detect events in order to trigger card&  sdio function
initialization and removals.

Please share any alternative approach you may be thinking on.

OK, this is how I see it.

- Treat the non-removable card as non-removable. So no need to do card detect emulation.

- Treat the GPIO power enable on wl1271 as VMMC supply. Use fixed regulator framework to define this regulator & supply. Even though you mention that it is not actually a supply, it fits well in the fixed supply framework.

- When the host controller is enumerated, the mmc core will power up the slot, find the sdio card, and probe the function driver (i.e. wl1271_sdio).

- if interface is not in use, the function driver must release the sdio host, and this should eventually disable the vmmc supply.

- Whenever the wlan interface must be brought up, wl1271_sdio, can claim the sdio host. this will cause the vmmc supply to be enabled, for as long as the interface is up.

Does this address all issues?

regards,
-roger
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