[PATCH 05/15] omap: hsmmc: add virtual card detect support

[Roger Quadros]

On 07/06/2010 01:22 PM, ext Ohad Ben-Cohen wrote:
> Hi Nicolas,
>
> On Tue, Jul 6, 2010 at 4:45 AM, Nicolas Pitre<nico at fluxnic.net>  wrote:
>> On Tue, 6 Jul 2010, Ohad Ben-Cohen wrote:
>>
>>> From: Ohad Ben-Cohen<ohadb at ti.com>
>>>
>>> Add support for software emulation of card detect
>>> events.
>>>
>>> This is required for specific controllers
>>> that are hard wired with embedded SDIO devices
>>> (such as TI's wl1271 WLAN device).
>>
>> Why?
>>
>> Many instances of hardwired SDIO based WLAN devices do exist already,
>> and they don't need extra card detect events to be generated.  The core
>> MMC code already triggers a probe for cards whenever a new host
>> controller is registered.
>
> We prefer not to power up the chip as early as boot time; instead, we
Why? if the card is hard wired with no card detect then it should be powered up. 
The function driver should power it down later if required. no?

> would like to have it powered off until the wlan interface is brought
> up, power it on when the interface is brought up,

If it was powered OFF then how did the wlan interface come into picture?

> and power it off again as soon as the interface is brought down again
> (to minimize power consumption when the wlan is not in use).
I agree, we some how need to power down the card when not in use in the right way.