On Thu, 22 Nov 2007 05:34:11 -0800 (PST)
Madhusudhan C <[EMAIL PROTECTED]> wrote:
> Hi Pierre,
>
> I have a question on the mmc_select_voltage fn of the mmc core file
> drivers/mmc/core/core.c.
>
> During the power up sequence the mmc_power_up fn sets the OCR bit to setup
> 3V. Subsequentely the mmc_select_voltage fn selects the lowest voltage
> the card can support.The host->ios.power_mode is not changed to MMC_POWER_UP
> before calling mmc_set_ios from this function hence the power_mode remains in
> MMC_POWER_ON state.So my question is, how should the controller driver handle
> this change in volatge. Under which case of power mode should the controller
> driver change the voltage again when a dual voltage card is detected?
>
To be completely correct, the MMC layer should probably power down the card
first, yes. Right now most drivers will handle all of these things as they see
fit. Haven't seen a single bug report about it yet so...
Just change the voltage in whatever way makes sense for your controller.
Rgds
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
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